THE QUALITY OF DRINKING WATER IN IRELAND
A REPORT FOR THE YEAR 2001 Environmental Protection Agency
Establishment The Environmental Protection Agency Act, - preparation and implementation of a 1992, was enacted on 23 April, 1992, and national hydrometric programme for the under this legislation the Agency was collection, analysis and publication of formally established on 26 July, 1993. information on the levels, volumes and flows of water in rivers, lakes and Responsibilities groundwaters; and The Agency has a wide range of statutory duties and powers under the Act. The main - generally overseeing the performance by responsibilities of the Agency include the local authorities of their statutory following: environmental protection functions.
- the licensing and regulation of Status large/complex industrial and other The Agency is an independent public body. processes with significant polluting Its sponsor in Government is the potential, on the basis of integrated Department of the Environment and Local pollution control (IPC) and the Government. Independence is assured application of best available technologies through the selection procedures for the for this purpose; Director General and Directors and the freedom, as provided in the legislation, to - the monitoring of environmental quality, act on its own initiative. The assignment, including the establishment of databases under the legislation, of direct responsibility to which the public will have access, for a wide range of functions underpins this and the publication of periodic reports independence. Under the legislation, it is a on the state of the environment; specific offence to attempt to influence the Agency, or anyone acting on its behalf, in - advising public authorities in respect of an improper manner. environmental functions and assisting local authorities in the performance of Organisation their environmental protection functions; The Agency’s headquarters is located in Wexford and it operates five regional - the promotion of environmentally sound inspectorates, located in Dublin, Cork, practices through, for example, the Kilkenny, Castlebar and Monaghan. encouragement of the use of environmental audits, the setting of Management environmental quality objectives and the The Agency is managed by a full-time issuing of codes of practice on matters Executive Board consisting of a Director affecting the environment; General and four Directors. The Executive Board is appointed by the Government - the promotion and co-ordination of following detailed procedures laid down in environmental research; the Act.
- the licensing and regulation of all Advisory Committee significant waste disposal and recovery The Agency is assisted by an Advisory activities, including landfills and the Committee of twelve members. The preparation and periodic updating of a members are appointed by the Minister for national hazardous waste management the Environment and Local Government plan for implementation by other bodies; and are selected mainly from those nominated by organisations with an interest - implementing a system of permitting for in environmental and developmental the control of VOC emissions resulting matters. The Committee has been given a from the storage of significant quantities wide range of advisory functions under the of petrol at terminals; Act, both in relation to the Agency and to the Minister. - implementing and enforcing the GMO Regulations for the contained use and deliberate release of GMOs into the environment; THE QUALITY OF DRINKING WATER IN IRELAND
A REPORT FOR THE YEAR 2001
Environmental Protection Agency An Ghníomhaireacht um Chaomhnú Comhshaoil P.O. Box 3000, Johnstown Castle Estate, Co. Wexford, Ireland.
Telephone : +353-53-60600 Fax : +353-53-60699 e-mail: [email protected] Website: www.epa.ie © Environmental Protection Agency 2002
Although every effort has been made to ensure the accuracy of the material contained in this publication, complete accuracy cannot be guaranteed. Neither the Environmental Protection Agency nor the author(s) accept any responsibility whatsoever for loss or damage occasioned or claimed to have been occasioned, in part or in full, as a consequence of any person acting or refraining from acting, as a result of a matter contained in this publication.
Parts of this publication may be reproduced without further permission, provided the source is acknowledged.
THE QUALITY OF DRINKING WATER IN IRELAND
A REPORT FOR THE YEAR 2001
Authors:- Mr. Darragh Page, Mr. Gerard O’Leary, Ms. Avril Boland, Dr. Conor Clenaghan and Dr. Matt Crowe.
ISBN 1-84095-097-8 Price €26.00 11/02/750 Contents
SUMMARY ...... viii 1. INTRODUCTION ...... 1 1.1. THE EUROPEAN COMMUNITIES (DRINKING WATER) REGULATIONS, 1988...... 1 1.2. THE EUROPEAN COMMUNITIES (DRINKING WATER) REGULATIONS, 2000...... 4 2. PARAMETER BY PARAMETER ANALYSIS OF DRINKING WATER ...... 9 2.1. INTRODUCTION...... 9 2.2. ALUMINIUM ...... 10 2.3. AMMONIUM ...... 13 2.4. TOTAL & FAECAL COLIFORMS ...... 14 2.5. COLOUR ...... 20 2.6. FLUORIDE ...... 21 2.7. HEAVY METALS...... 24 2.8. IRON ...... 25 2.9. MANGANESE ...... 27 2.10. NITRATE ...... 29 2.11. NITRITE ...... 33 2.12. ODOUR...... 34 2.13. TASTE...... 35 2.14. pH ...... 36 2.15. TRIHALOMETHANES ...... 38 2.16. TURBIDITY ...... 39 2.17. CRYPTOSPORIDIUM ...... 41 2.18. NEW PARAMETERS INTRODUCED IN THE 2000 REGULATIONS ...... 42 2.19. PARAMETERS WITH REVISED STANDARDS IN 2000 NEW REGULATIONS ...... 44 3. SANITARY AUTHORITY RESULTS ...... 49 3.1. INTRODUCTION...... 49 3.2. CARLOW ...... 50 3.3. CAVAN ...... 52 3.4. CLARE ...... 54 3.5. CLONMEL ...... 56 3.6. CORK CITY ...... 57 3.7. CORK (NORTHERN AREA)...... 58 3.8. CORK (SOUTH AREA)...... 60 3.9. CORK (WEST AREA) ...... 61 3.10. DONEGAL ...... 62
iii 3.11. DROGHEDA ...... 63 3.12. DUBLIN CITY ...... 64 3.13. DUNDALK ...... 65 3.14. DUN LAOGHAIRE-RATHDOWN ...... 66 3.15. ENNIS ...... 67 3.16. FINGAL ...... 68 3.17. GALWAY CITY ...... 69 3.18. GALWAY (COUNTY) ...... 70 3.19. KERRY ...... 72 3.20. KILDARE ...... 73 3.21. KILKENNY ...... 74 3.22. LAOIS ...... 75 3.23. LEITRIM...... 76 3.24. LIMERICK (COUNTY) ...... 78 3.25. LIMERICK CITY ...... 79 3.26. LONGFORD ...... 80 3.27. LOUTH ...... 81 3.28. MAYO...... 82 3.29. MEATH...... 83 3.30. MONAGHAN ...... 84 3.31. NORTH TIPPERARY...... 85 3.32. OFFALY ...... 86 3.33. ROSCOMMON...... 87 3.34. SLIGO TOWN ...... 88 3.35. SLIGO COUNTY ...... 89 3.36. SOUTH DUBLIN ...... 90 3.37. SOUTH TIPPERARY...... 91 3.38. WATERFORD CITY ...... 92 3.39. WATERFORD COUNTY ...... 93 3.40. WESTMEATH ...... 94 3.41. WEXFORD ...... 95 3.42. WICKLOW ...... 96 4. EPA AUDITS...... 97 4.1. INTRODUCTION...... 97 4.2. AUDITS ...... 97 5. CURRENT ISSUES ...... 100 5.1. INTRODUCTION...... 100 5.2. RESPONSIBILITY FOR PRODUCING AND MONITORING DRINKING WATER ...... 100
iv 5.3. CHLORINATION...... 100 5.4. FLUORIDATION ...... 102 5.5. BOTTLED WATER ...... 104 5.6. QUALITY IN RURAL WATER SCHEMES ...... 105 5.7. IMPLEMENTATION OF THE 2000 DRINKING WATER REGULATIONS AND IMPROVED COMMUNICATION...... 106 6. CONCLUSIONS...... 107 7. RECOMMENDATIONS ...... 109 7.1. MANAGEMENT OF DRINKING WATER...... 109 7.2. MONITORING AND REPORTING...... 110 7.3. COMMUNICATION...... 111 7.4. INFRASTRUCTURE AND PLANNING...... 111 8. SUGGESTED FURTHER READING ...... 112 APPENDIX A Drinking Water Regulations Parameters and Standards...... 114 APPENDIX B Extract from S.I. No 439 of 2000 European Communities (Drinking Water) Regulations, 2000 ...... 115
v Acknowledgements
The help of those sanitary authorities which contributed data to the Environmental Protection Agency for the purposes of this report is gratefully acknowledged. Thanks are also due to EPA staff members Ms. Eileen Carroll, Mr. Frank Clinton, Mr. David Smith, Ms. Deirdre Kirwan, Ms. Caitriona Collins and Ms. Shirley Murphy.
vi Abbreviations & Symbols
Al Aluminium Cd Cadmium Co County Co Co County Council Cr Chromium Cu Copper EPA Environmental Protection Agency F Fluoride Fe Iron Gr Groundwater GWS Group Water Scheme/Schemes HACCP Hazard Analysis Critical Control Points Hg Mercury MAC Maximum Admissible Concentration mg/l Milligrams per litre Mn Manganese MRC Minimum Required Concentration na Information not available to sanitary authority and / or EPA n/a Not applicable NDSC National Disease Surveillance Centre
NH4 Ammonium Ni Nickel
NO3 Nitrate NO2 Nitrite Pb Lead PWS Public Water Supply/Supplies µg/l Micrograms per litre SMP Small Private Supplies/Wells WHO World Health Organisation
vii Quality of Drinking Water in Ireland A Report For The Year 2001
Summary
Overview
The classification of water as fit for human consumption is based on the European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988, which give formal effect in Irish law to the EU Drinking Water Directive [80/778/EEC]. The Drinking Water Regulations cover a total of 53 bacteriological, chemical and physical parameters*. For each of the 53 parameters specified in Irish law, an upper concentration limit (or maximum admissible concentration) is specified. Hence, a comparison between monitoring results from a drinking water tap and the upper concentration limits allows one to judge whether a supply is fit for human consumption.
Persons producing drinking water must provide water which conforms to the quality standards as laid down by the 1988 Ministerial Regulations. Though up to 53 different quality standards exist, there is a smaller group of "core" parameters, between 8 and 14 in all, which form a suitable basis on which the potability of water may be generally assessed in the majority of cases.
In the year 2001, 22,453 samples, which involved 146,352 individual tests of drinking water, were taken by local authorities. The Environmental Protection Agency (EPA) estimate that local authorities (also called sanitary authorities) produced and distributed 92.0% of the sampled drinking water, with 7.9% distributed by group water schemes and a further 0.1% distributed by private sources (see Figure 1).
Group Water Small Private Schemes Supplies 7.9% 0.1%
Public Water Supplies 92.0%
Public Water Supplies Group Water Schemes Small Private Supplies
Figure 1: Population Served by Water Supplies Sampled in 2001.
The drinking waters produced and distributed by local authorities are termed public water supplies (PWS) and during 2001, some 904 individual supplies were sampled. Group water schemes (GWS), on the other hand, obtain their water from either a public authority supply or from a private source (with or without treatment). Though the public supplies distribute vastly greater quantities of water, as outlined above, the group water schemes are more numerous. During 2001, some 1,536 individual group water schemes (of the estimated 5,500 group water schemes in Ireland) were sampled.
* There are two further parameters for softened water which fix Minimum Required Concentrations.
viii Quality of Drinking Water in Ireland A Report For The Year 2001
The significant increase in the monitoring of drinking water in 2000 (34% on average for all parameters analysed), as reported in last years report, was maintained in 2001 and indeed there was a further modest increase of 3% in the number of analyses carried out in 2001 (see Figure 2). It is possible that there would have been a greater increase in the level of sampling were it not for the foot and mouth crisis which restricted sampling in the earlier part of 2001. The overall level of compliance with the standards for public water supplies and group water schemes combined was 94.3% in 2001, which is the same as that reported for 2000 (see Figure 3). For public water supplies, overall compliance in 2001 was 96.0% compared with 95.7% in 2000. For group water schemes, overall compliance in 2001 was 89.5% compared with 91.2% in 2000.
150000 No. of Tests Exceeding the Standards
No. of Compliant Tests 120000
90000
60000 No. of Tests of No.
30000
0 19921993 1994 1995 1996 1997 1998 1999 2000 2001 Year
Figure 2: Overall Summary of Compliance with the Drinking Water Standards 1991-2001.
Tests Exceeding the Standards 5.7%
Compliant Tests 94.3%
Compliant Tests Tests Exceeding the Standards
Figure 3: Overall Percentage Compliance in 2001.
ix Quality of Drinking Water in Ireland A Report For The Year 2001
A compliance rate of 94.3% means that 5.7% of tests conducted failed to comply with a standard. This means that 8,344 exceedances were recorded out of a total of 146,352 tests conducted. Of these exceedances, 4,348 occurred in public water supplies while 3,718 occurred in group water schemes (the remainder occurred in small private supplies). Parameters most frequently exceeded in 2001 were total coliforms (Total1 3,121; PWS 1,124; GWS 1,793), faecal coliforms (Total 1,520; PWS 422; GWS 1,073), colour (Total 1,031, PWS 503; GWS 518), odour (Total 771; PWS 588; GWS 180), iron (Total 606; PWS 324; GWS 258) manganese (Total 594; PWS 259; GWS 315) and aluminium (Total 585; PWS 547; GWS 37). Recent trends in the total number of exceedances for core parameters, in public water supplies and
Table 1: Total Number of Exceedances of the Core Parameters from 1999 to 2001. Public Water Supplies Group Water Schemes 1999 2000 2001 1999 2000 2001 Aluminium 366 382 547 28 159 37 Ammonium 15 29 14 26 89 63 Colour 476 555 503 177 349 518 Faecal Coliforms 501 510 422 598 1,206 1,073 Fluoride 390 427 311 21 38 26 Heavy Metals 17 13 16405 Iron 292 359 324 172 347 258 Manganese 208 266 259 175 387 315 Nitrates 32 38 33 27 39 44 Nitrites 8251663340 Odour 507 418 588 37 139 180 pH 99 141 133 51 81 104 Taste 266 130 276 8 82 101 Total Coliforms 1,038 1,333 1,124 872 1,712 1,793 Turbidity 223 128 204 93 126 234
Table 2: Percentage Compliance of the Core Parameters from 1999 to 2001. Public Water Supplies (%) Group Water Schemes (%) 1999 2000 2001 1999 2000 2001 Aluminium 92.1 92.0 91.2 91.1 88.4 92.1 Ammonium 99.6 99.3 99.7 98.1 97.4 98.1 Colour 94.2 94.1 94.6 88.6 90.5 85.4 Faecal Coliforms 96.2 96.7 97.2 74.1 70.8 74.1 Fluoride 94.5 94.3 95.8 89.1 81.2 89.5 Heavy Metals 99.4 99.6 99.8 99.4 100 99.5 Iron 92.2 91.6 94.7 87.8 88.7 87.6 Manganese 92.3 92.4 95.1 87.3 87.2 84.7 Nitrates 99.2 99.3 99.3 98.2 98.9 98.7 Nitrites 99.8 99.4 99.6 99.5 99.0 98.7 Odour 94.8 96.3 94.7 97.7 96.3 94.5 pH 98.8 98.4 98.6 96.7 97.8 97.1 Taste 96.7 98.5 96.9 98.6 96.6 93.7 Total Coliforms 92.1 91.3 92.6 62.2 58.6 56.8 Turbidity 97.1 98.5 97.7 93.5 96.5 93.3
1 The total number of exceedances includes public water supplies, group water schemes and small private supplies. For the purposes of this report the number of exceedances of the standards in small private supplies is not reported although can be calculated as the difference between the total number of exceedances minus the number of exceedances in public water supplies and group water schemes. x Quality of Drinking Water in Ireland A Report For The Year 2001
group water schemes, are presented in Table 1 for 1999, 2000 and 2001.
Key Indicators
Overall Level of Compliance
Figure 5 presents recent trends in overall compliance with the standards for all water supplies combined, public water supplies and group water schemes. Overall, compliance with the drinking water standards has remained unchanged over the period 1999 to 2001. Compliance with the standards in public water supplies has improved slightly over the same period while the compliance rate for group water schemes improved between 1999 and 2000 only to deteriorate between 2000 and 2001. The higher quality of drinking water from public water supplies compared to that in group water schemes is clearly illustrated on Figure 5.
Total and Faecal Coliforms
The presence of coliforms in a drinking water sample suggests inadequate treatment, post treatment contamination or excessive nutrients. The coliform test is therefore an indicator of treatment efficiency and the integrity of the distribution system. Overall, compliance with the total coliform standard improved slightly by 0.2% in 2001 in comparison to 2000. This was particularly noticeable in public water supplies where there was a reduction in the number of samples containing coliforms (1,124 in 2001 compared to 1,333 in 2000) leading to an improvement in the coliform compliance rate from 91.3% in 2000 to 92.6% in 2001. However, despite an almost identical number of samples from group water schemes being analysed for total coliforms in 2000 and 2001, there was an increase in the number of samples containing coliforms from 1,712 in 2000 to 1,793 in 2001 leading to a decline in the compliance rate from 58.6% in 2000 to 56.8% in 2001. In other words, 43.2% of samples analysed for coliforms originating from group water schemes contained this indicator organism for water quality. Trends in percentage compliance with the total coliform standard, for both public water supplies and group water schemes, are shown on Figure 6. The downward trend for group water schemes is a particular cause for concern.
100
95
90
85
80 Overall Percentage Compliance Overall Percentage 75 Overall PWS GWS
1999 2000 2001
Figure 5: Overall Compliance with the Standards in all Supplies Combined, Public Water Supplies and Group Water Schemes.
xi Quality of Drinking Water in Ireland A Report For The Year 2001
100%
90%
80%
70% centage Compliance
Per 60%
50% 1993 1994 1995 1996 1997 1998 1999 2000 2001
Year Group Water Schemes Public Water Supplies
Figure 6: Percentage of Samples Free From Total Coliforms Over the Period 1993 to 2001.
Not all coliforms are of faecal origin and to obtain a better picture of the quality of water in a supply a test is carried out to determine whether the coliforms detected are of faecal origin. The presence of a faecal coliform in a water supply is a definite indication that faecal contamination (human or animal) of the water supply has occurred. There has been a noticeable decrease in the numbers of samples containing faecal coliforms in 2001 in both public water supplies and group water schemes. Compliance with the faecal coliform standard in public water supplies improved from 96.7% in 2000 to 97.2% in 2001 and there was a reduction in the number of samples containing faecal coliforms from 510 in 2000 to 422 in 2001. Similarly, there has been an improvement in compliance with the faecal coliforms standard in group water schemes with compliance in 2001 at 74.1% compared to 70.8% in 2000. This corresponds to a reduction in samples containing faecal coliforms from 1,206 in 2000 to 1,073 in 2001.
Although this improvement is to be welcomed, it must be noted that compliance with the faecal coliforms standard is still very poor in group water schemes lagging far behind that of public water supplies, and remains unacceptable. The percentage of samples free of faecal coliforms is illustrated in Figure 7. Analysis of the exceedances of the faecal coliforms standard on a scheme by scheme basis indicates that 720 (79.6%) public water supplies and 1,051 (68.4%) group water schemes monitored were free of faecal contamination in 2001. Conversely, 184 public water supplies and 485 group water schemes exhibited some degree of faecal contamination during 2001, although the majority of exceedances recorded were moderate incidents. The actual number of group water schemes exhibiting faecal contamination is probably higher than 485 as only 1,536 schemes out of a total estimate of 5,500 schemes were monitored in 2001.
xii Quality of Drinking Water in Ireland A Report For The Year 2001
100%
90%
80%
70% centage Compliance
Per 60%
50% 1993 1994 1995 1996 1997 1998 1999 2000 2001
Year Group Water Schemes Public Water Supplies
Figure 7: Percentage of Samples Free From Faecal Coliforms Over the Period 1993 to 2001.
Challenges Ahead
Addressing the poor quality of many of the group water schemes and ensuring that public and private water supplies are going to be able to meet the requirements of the new drinking water Regulations, (the European Communities (Drinking Water) Regulations, 2000, which take effect from January 1, 2004) are the priority issues in relation to the quality of drinking water in Ireland. Successive EPA reports have recommended that the necessary works be undertaken to ensure that group schemes in particular will meet the drinking water standards. However, the focus should not entirely be on the group water schemes as some public water supplies have difficulties in meeting some of the current standards. Repeated breaches of the same standards from year to year have been noted in several supplies. The EPA is of the opinion that formal documented procedures, which form part of an overall documented management and control system, are an integral part of ensuring that exceedances are dealt with in an appropriate manner. Such procedures assist the supply in returning to full compliance in as short a period as possible.
The large number of small group water schemes in Ireland, and to a lesser extent, small public supplies, is a significant barrier to improving the quality of drinking water. Large numbers of small supplies results in operational and management difficulties for those responsible for the production and supply of drinking water as each individual supply requires management, maintenance and monitoring. Consideration should therefore be given to rationalising water supply in parts of Ireland with large numbers of small supplies with a view to reducing the overall number of supplies and increasing their average size.
Successive EPA reports on the quality of drinking water in Ireland provide clear evidence that water supplied by sanitary authorities is safer to drink than water supplied by privately operated group schemes. Where persistent problems with group schemes exist, serious consideration should be given to having these group schemes brought under the control of sanitary authorities.
xiii Quality of Drinking Water in Ireland A Report For The Year 2001
xiv Quality of Drinking Water in Ireland A Report For The Year 2001
1. INTRODUCTION
Public health and aesthetics (i.e. appearance, taste and smell) are the principal reasons underpinning the need for the treatment of water intended for human consumption. At the start of the 1900s diseases such as cholera and typhoid fever prompted the development of water treatment technologies such as filtration and disinfection devices. In the 1970s there were significant developments in treatment technologies and this was coupled with an increasing understanding of the potential health effects of organic and inorganic substances present in drinking water. This has lead to a broadening of what is understood by "water fit for human consumption" and a consequent need for more extensive monitoring of drinking water.
The classification of water as potable (i.e. fit for human consumption) or otherwise is based on the European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988 (S.I. No. 81 of 1988) which give formal effect in Irish law to the EU Drinking Water Directive [80/778/EEC]. These Regulations set standards for in excess of 50 parameters which include microbiological, organic and inorganic standards. In Ireland, bodies whose function it is to provide us with drinking water are known as "Sanitary Authorities" and these comprise mostly County and Borough Councils as well as City and Town Councils. Regular sampling of water supplies is carried out by or on behalf of these authorities and the samples are analysed for a range of constituents, generally referred to as "parameters of water quality". Testing covers physical, chemical and bacteriological aspects of water quality and the results form the basis on which the overall quality of drinking water can be assessed. The task of providing good quality drinking water, distributing it and assessing its quality as it reaches the consumer is the responsibility of the local sanitary authority
The Environmental Protection Agency (EPA) has statutory responsibilities in regard to drinking water. Section 58 of the Environmental Protection Agency Act, 1992, requires the Agency to prepare and submit to the Minister for the Environment and Local Government a report each year on the monitoring by sanitary authorities of drinking water supplies and an assessment of the results. The present report, the thirteenth in the series, covers the year 2001 and gives a comparative assessment of data for the period 1999-2001. The analytical data on which this report is based are generated by sanitary authorities by virtue of their monitoring programmes under the European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988.
In the report, quality variations on a national basis are considered, emphasis being placed largely on a parameter-by-parameter assessment. The report presents information on 14 key parameters, and provides a summary overall assessment of drinking water quality in each sanitary authority area. More detailed analysis of the monitoring data submitted by the sanitary authorities is included on the CD ROM version of "The Quality of Drinking Water in Ireland: A Report for the Year 2001".
1.1. THE EUROPEAN COMMUNITIES (QUALITY OF WATER INTENDED FOR HUMAN CONSUMPTION) REGULATIONS 1988
The European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988 (S.I. 81 of 1988) give formal effect in Irish law to the EU Drinking Water Directive [80/778/EEC]. Chief among the requirements of the 1988 Regulations are the following:
✒ all water for human consumption, whether in its original state or after treatment, regardless of origin, is covered, including water used in the food industry but excluding natural mineral waters or medicinal waters;
1 Quality of Drinking Water in Ireland A Report For The Year 2001
✒ national quality standards, the legal limits which must not be exceeded, are fixed for over 50 parameters;
✒ in particular circumstances, and only where there is no risk to public health, the Minister for the Environment may grant "departures" [exemptions] from the standard set for particular parameters;
✒ minimum frequencies of sampling and analysis, for the respective groups of parameters which are also defined, are established by the Regulations. Samples are to be taken from water at the point where it is made available to the consumer; that is, at the consumer’s tap.
In regard to remedying water quality deficiencies confirmed by sampling and analysis, the requirements of the 1988 Regulations were subsequently supplanted by those of the European Communities (Quality of Water Intended for Human Consumption) (Amendment) Regulations, 1999 (S.I. No. 350 of 1999) , which are broader in their coverage. However, it was subsequently decided that further Regulations would be required to deal comprehensively with the problematic private supplies and in June 2000 the European Communities (Quality of Water Intended for Human Consumption) (Amendment) Regulations, 2000 (S.I. No. 177 of 2000) were made.
Under these latest Regulations, Article 8 of the 1988 Regulations is replaced by the following:
8. (1) Where it is found, as a result of monitoring carried out under article 7, that the quality of water intended for human consumption does not meet the requirements of these Regulations, the sanitary authority shall:-
(a) take all reasonable steps to warn users of the water supply where there is an unacceptable risk to public health,
(b) in the case of a public water supply, prepare an action programme for the improvement of the quality of the water as soon as practicable,
(c) in the case of a private water supply serving 50 persons or more serve, within 14 days of receipt by the sanitary authority of the monitoring results, a notice in writing on the person or, where there is more than one such person, each person responsible for that supply requiring that person, or persons as the case may be, to prepare and implement an action programme, including such interim measures as may be appropriate, for the improvement of the quality of the water so as to secure compliance with these Regulations as soon as practicable and not later than -
(i) 31 December 2003 in relation to the water quality standards specified in Part 1 of the Schedule in relation to matters which present a risk to public health, and
(ii) 31 December 2006 in relation to all the water quality standards specified in Part 1 of the Schedule,
(d) in the case of a private water supply serving fewer than 50 persons serve, as soon as practicable, a notice on the person responsible for the supply of the measures which should be taken for the improvement of the quality of the water.
2 Quality of Drinking Water in Ireland A Report For The Year 2001
(2) An action programme under sub-article (1)(b) shall include such interim measures as may be appropriate and shall be implemented by the sanitary authority so as to secure compliance with these Regulations
(3) An action programme under sub-article (1)(c) shall have regard to the provisions of any strategic rural water plan for the area in which the water supply is situate.
The 1988 Regulations also address the frequency of sampling and analysis. The basic principle underlying the monitoring is that the extent to which sampling and analysis are carried out increases with the magnitude of the populations served by the respective supplies. Table 1.1 below (taken from the Regulations) shows the population bands and the minimum analysis frequencies specified for each. Table 1.2 provides a description of the monitoring requirements referred to in Table 1.1. These cover populations from 1,000 to 1,000,000 people (assuming a daily per capita consumption of 200 litres). Only in two cases does the frequency remain to be determined by the sanitary authorities.
Table 1-1: Minimum Frequency Of Standard Analysis Required By The Regulations.
Volume of Population Minimum Number of Samples per Year water Concerned (on produced/ basis of 200 l. ANALYSIS distributed per person per m3/day day) C1 C2 C3 C4 200 1,000 2 1 (a) Frequency to be determined by the 500 2,500 3 1 (a) Sanitary Authority as the situation 1,000 5,000 6 2 1 requires 2,000 10,000 12 3 1 10,000 50,000 60 6 1 20,000 100,000 120 12 2 30,000 150,000 180 18 3 60,000 300,000 360 36 6 100,000 500,000 360 60 10 200,000 1,000,000 360 120 20
(a) Frequency to be determined by the Sanitary Authority but the requirement in article 7 (5) shall also apply. [The requirement, mentioned above, is that water used in the food industry and effecting the wholesomeness of the foodstuff in its finished form shall be monitored at least once a year]
3 Quality of Drinking Water in Ireland A Report For The Year 2001
Table 1-2: Schedule of Parameters to be Monitored.
Minimum Monitoring/ Current Monitoring/ Periodic Monitoring/ Occasional Analysis C1(1) Analysis C2(1) Analysis C3(1) Monitoring(3)/ Analysis C4(1) Odour Odour Current monitoring (C2) The sanitary authority to Taste Taste analyses plus other determine the Conductivity(2) Temperature parameters determined parameters according to Total Coliforms or Conductivity(2) by the sanitary authority circumstances, taking Total Counts at 22¡ pH "having regard to all account of all factors and 37¡C Nitrates factors which may affect which might have an Faecal Coliforms Nitrites the quality of drinking adverse effect on the Ammonia water supplied to users quality of drinking water Total Coliforms and which may allow the supplied to consumers Total Counts at 22¡ and ionic balance of the 37¡C constituents to be Faecal Coliforms assessed" (1) Designations are those contained in the Regulations. (2) "Or other physico-chemical parameter". (3) Monitoring in special situations or in case of accidents.
The monitoring requirements are quite clear for all supplies for populations over 1,000 persons and can be regarded as the lowest permissible frequencies. There is a most important proviso, however. Considerably more monitoring may be required in the following circumstances: (a) where past monitoring has indicated quality problems, (b) where there is a significant degree of variability in the water quality parameters and (c) where water requires to be disinfected as specified in Article 7(6) of the 1988 Regulations. It follows that such extra monitoring may be confined to those parameters which are particularly relevant in a given situation. It is also most important that monitoring should be continued for any parameter in respect of which a departure has been granted by the Minister. In such cases it is recommended that the parameters involved should be monitored at least at the minimum frequency for C1 analysis.
As noted above, the Regulations state that, in the case of supplies serving fewer than 1,000 people or producing or distributing less than 200 cubic metres of water per day, monitoring shall be "on such occasions and to such extent as [the sanitary authority] shall consider necessary having regard to: (a) the patterns of standard analyses specified in Table A of Part II of the Schedule, (b) their knowledge of the quality of water in their functional area, and (c) any factors, coming to attention which are likely to cause deterioration of quality". The implementation of the Regulations for supplies serving fewer than 1,000 people needs careful consideration as, under the Regulations, the sanitary authorities have specific responsibilities for all water supplies, including wells serving single households.
1.2. THE EUROPEAN COMMUNITIES (DRINKING WATER) REGULATIONS, 2000
The EU adopted a new Drinking Water Directive (98/83/EC) in November 1998 and this was transposed into Irish law on the 18th December, 2000 by the European Communities (Drinking Water) Regulations, 2000 (S.I. 439 of 2000). Ireland was one of the few EU countries to have transposed the Directive before the specified deadline of 25th December 2000. This set of Regulations is radically different from its predecessor and will entail very significant changes in virtually all aspects of implementation - sample
4 Quality of Drinking Water in Ireland A Report For The Year 2001
numbers, parameters, parameter classes, extent of coverage, and so on. It is important to note that the commencement date for the new Regulations is 1 January 2004, however, sanitary authorities are advised to commence preparation of the introduction of the new Regulations immediately.
The 2000 Regulations:
◆ set standards in relation to the quality of water intended for drinking water, cooking, food preparation, other domestic purposes and food production (other than natural mineral waters, bottled water, certain medicinal products and exempted supplies);
◆ provide for temporary departures from the standard where there is no threat to human health; and
◆ require that information is made available to consumers in relation to various matters including water quality, exempted supplies, departures granted, precautionary measures and remedial action in case of non-compliant supplies.
For the purposes of this report, a reference to Regulations/standards is a reference to the 1988 Regulations/standards (unless otherwise stated).
In general, a wide ranging overhaul of the original 1988 Regulations has been carried out. As well as introducing a series of new or revised standards, termed "parametric values" and downgrading some existing standards to "indicator" status, the new Regulations introduce a revised regime for correcting breaches of standards.
The Regulations prescribe 48 parametric values which are classified as being either microbiological, chemical or indicator parameters. These are listed in Table 1-3. New parameters include E. coli, Enterococci, acrylamide, benzene, benzo(a)pyrene, bromate, 1,2 dichloroethane, epichlorohydrin, polycyclic aromatic hydrocarbons, tetrachloroethene and trichloroethene, trihalomethanes, vinyl chloride, Clostridium perfringens, tritium and total (radioactive) indicative dose. It is noted that the standards specified in the new Regulations for ammonium and fluoride are more stringent than those specified in the 1998 Directive.
Parameters no longer specified are faecal coliforms (replaced by E. coli), barium, magnesium, organochlorine compounds, phosphorus, potassium, silver, surfactants, zinc, alkalinity, calcium, dry residues, hydrogen sulphide, kjeldhal nitrogen, phenols, substances extractable in chloroform, suspended solids, temperature and total hardness.
The two monitoring categories are respectively designated check monitoring and audit monitoring, the latter requiring the fewer number of samples but being by far the more demanding in analytical terms.
The purpose of check monitoring is to provide information on the organoleptic and microbiological quality of the water supplied for human consumption as well as information on the effectiveness of drinking-water treatment (especially of disinfection) where it is used.
The purpose of audit monitoring is to provide the information necessary to determine whether or not all the standards specified in Part I of the Schedule to the Regulations are being complied with. All such parameters must be subject to audit monitoring unless it can be established by a sanitary authority, for a period of time to be determined by it, that a parameter is not likely to be present in a given supply in
5 Quality of Drinking Water in Ireland A Report For The Year 2001
concentrations which could lead to the risk of a breach of the relevant parametric value. Table 1.3 provides a summary of the classification of the parameters and of the requirements of the two monitoring categories, while Table 1.4 provides the minimum sampling frequencies that will apply.
6 Quality of Drinking Water in Ireland A Report For The Year 2001
Table 1-3: Analytical Determinands Classified According to Parameter Category and Monitoring Category. Parameter Parameter Category Monitoring Category Chemical Indicator Micro Check Audit Acrylamide Yes - - - Yes Aluminium - Yes - Yes Yes Ammonium - Yes - Yes Yes Antimony Yes - - - Yes Arsenic Yes - - - Yes Benzene Yes - - - Yes Benzo(a)pyrene Yes - - - Yes Boron Yes - - - Yes Bromate Yes - - - Yes Cadmium Yes - - - Yes Chloride - Yes - - Yes Chromium Yes - - - Yes Clostridia perfringens (sp) - Yes - Yes¦- Yes‡ Colour - Yes - Yes Yes Conductivity - Yes - Yes Yes Copper Yes - - - Yes† Cyanide Yes - - - Yes 1,2-Dichloroethane Yes - - - Yes E. coli --YesYes Yes Enterococci - - Yes - Yes‡ Epichlorohydrin Yes - - - Yes Fluoride Yes - - - Yes Hydrogen ion concentration - Yes - Yes Yes Iron - Yes - Yes ¦ Yes Lead Yes - - - Yes † Manganese - Yes - - Yes Mercury Yes - - - Yes Nickel Yes - - - Yes† Nitrate Yes - - - Yes Nitrite Yes - - Yes¦ Yes Odour - Yes - Yes Yes Oxidisability - Yes - - Yes Pesticides Yes - - - Yes Pesticides - Total Yes - - - Yes Polycyclic aromatic hydrocarbon Yes - - - Yes Selenium Yes - - - Yes Sodium - Yes - - Yes Sulphate - Yes - - Yes Taste - Yes - Yes Yes Tetrachloroethene Yes - - - Yes Colony count 22¼C - Yes - - Yes Coliform bacteria - Yes - Yes Yes Total organic carbon - Yes - - Yes Trichloroethene Yes - - - Yes Trihalomethanes Ð Total Yes - - - Yes Turbidity - Yes - Yes Yes Vinyl chloride Yes - - - Yes
7 Quality of Drinking Water in Ireland A Report For The Year 2001
¦ Parameter to be determined in Check Monitoring in certain circumstances only. † Monitoring procedure to be determined by Minister. ‡ Parameter to be determined in Audit Monitoring in certain circumstances only.
Table 1.4: Minimum Monitoring Frequencies.
Volume of water Estimated Check monitoring Audit monitoring distributed or produced Population Served Number of samples Number of samples each day within a supply per year per year zone (m3)
>10 ≤ 100 50-500 2 To be determined by the sanitary authority
>100 ≤ 1,000 500-5,000 4 1
>1,000 ≤10,000 >5,000-50,000 4 1 + 1 for each 3,300 m3/d [16,500 pop] and part there of the total volume >10,000 ≤100,000 >50,000-500,000 +1 for each 1,000 m3/d 3 [5,000 pop] and part +1 for each 10,000 thereof of the total m3/d volume [50,000 pop] and part thereof of the total volume >100,000 >500,000 10 +1 for each 25,000 m3/d [125,000 pop] and part thereof of the total volume
Other features of the Regulations include:
◆ the assignment to the EPA of the function of granting departures from the standards as of 1st January 2004;
◆ the introduction of time limits for compliance with the standards by the public and private supplier;
◆ the provision for offences and penalties in the case of private water suppliers which fail to comply with a notice served by a sanitary authority;
A guidance note entitled "European Communities (Drinking Water) Regulations, 2000: A Handbook on Implementation for Sanitary Authorities" will be published by the Agency to assist sanitary authorities in the implementation of these Regulations.
8 Quality of Drinking Water in Ireland A Report For The Year 2001
2. PARAMETER BY PARAMETER ANALYSIS OF DRINKING WATER
2.1. INTRODUCTION
The classification of a water as potable (i.e. fit for drinking) or otherwise is not just based on the opinion of an individual analyst but on the requirements of the 1988 "Drinking Water Regulations" made by the then Minister for the Environment.
The Drinking Water Regulations cover a total of 53 bacteriological, chemical and physical parameters for each of which an upper concentration limit or MAC [Maximum Admissible Concentration] is specified. There are two further parameters for softened waters which fix Minimum Required Concentrations [MRC].
The relevance of the various standards depends in large part on the local circumstances which apply to a given water supply. For example, if the source is a boggy surface water, consideration of colour and pH (i.e. acidity or alkalinity) may be important. In a mineral-rich area the presence of iron or manganese may be a major influence on quality. If the water is supplied, say, to a block of older urban houses with metallic piping the presence of lead may be an issue.
As a general rule in Ireland, far and away the most important standards are those which relate to contamination by sewage or animal slurries. The relevant standards are those for "Total Coliforms" and "Faecal Coliforms", though others may also be applied in particular circumstances. This chapter provides details of the extent of compliance (or otherwise) with the Regulations for 14 principal water quality parameters. Details are also provided of the results of the monitoring for trihalomethanes, though not included as part of the current set of Regulations.
In an attempt to put the 14 principal water quality parameters into context a brief background description for each parameter is presented along with a categorisation of any exceedance which occurs into one of four bands. The bands are intended to indicate in approximate terms moderate, serious, very serious and gross degrees of contamination. The bands are customised for each parameter, taking account of the maximum admissible concentration as set out in the Regulations. Thus for example, the maximum admissible concentration for ammonium is 0.3 mg/l and any exceedance for this parameter is divided into one of the following four bands as shown on Table 2.1;
Table 2-1: Classification of Ammonium Exceedances.
Band Concentration Type of Exceedance 1> 0.3 and ≤ 0.4 mg/l Moderate 2> 0.4 and ≤ 0.6 mg/l Serious 3> 0.6 and ≤ 1.0 mg/l Very Serious 4 >1.0 mg/l Gross
The discussion below deals largely with exceedances of the Drinking Water Regulations. Where exceedances occur, it is essential that the sanitary authorities address them. However, there are clearly degrees of gravity in the effects for the health and well-being of the public, who consume drinking water. The consequences of supplies which, say, contain one or two total coliforms per 100 ml, on the one hand,
9 Quality of Drinking Water in Ireland A Report For The Year 2001
and hundreds of faecal coliforms, on the other will be significantly different. It should not be inferred from this example that the EPA condones minor exceedances of the standards. On the contrary, what this report seeks to present is an objective statement of the facts derived from the sanitary authority monitoring activities, and to set the analytical details in perspective.
2.2. ALUMINIUM
Aluminium is one of the most abundant elements in the earth’s crust. A salt, aluminium sulphate, is very widely used for colour and colloid-removal in the treatment of waters for drinking. The World Health Organisation (WHO) suggest that human exposure to aluminium may occur through a variety of routes, with drinking water probably contributing less than 5% of the total intake.
The WHO Guidelines for Drinking-Water Quality states that "in some studies, aluminium has appeared to be associated with the brain lesions characteristic of Alzheimer disease". However, it concludes that "there is a need for further studies, but the balance of epidemiological and physiological evidence at present does not support a causal role for aluminium in Alzheimer’s disease. Therefore, no health-based guideline value is recommended. However, a concentration of aluminium of 0.2 mg/l in drinking water provides a compromise between the practical use of aluminium salts in water treatment and discoloration of distributed water".
A total of 6,704 samples were analysed for aluminium in 2001, representing an increase of approximately 8% over the year 2000. The vast majority of these samples (6,183) were taken from public water supplies. The overall percentage compliance (91.3%) remained the same in 2001 as in 2000. However, there was a slight drop in compliance in public water supplies from 92.0% to 91.2% (Figure 2-1) over the same period. There was an apparent improvement in compliance noted in group water schemes, although the number of samples taken was relatively small. The use of alum as a treatment chemical in group water schemes is uncommon and hence monitoring of aluminium in group water schemes is, in most cases, unnecessary.
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-1. Aluminium Compliance in the Period 1999 to 2001.
10 Quality of Drinking Water in Ireland A Report For The Year 2001
The majority of aluminium exceedances are classified as moderate, as they have been in previous years reports. However, there has been a noticeable increase in serious, very serious and gross exceedances that needs to be addressed (Figure 2-2).
Gross exceedances of aluminium were noted in public water supplies in Cavan (5 exceedances), Donegal (7 exceedances), Kerry (4 exceedances), Leitrim (16 exceedances) and South Tipperary (5 exceedances). Public water supplies where compliance with the aluminium standard is a particular problem include Ballyshannon, Gortahork-Falcarragh, Lettermacaward (all Donegal), Carrigallen (Leitrim) and Enniskerry (Wicklow). All samples analysed for aluminium in these supplies exceeded the standard. The Agency urges corrective action to be taken at each of these treatment plants.
Exceedances of the aluminium standard are attributed to poor control of the alum dosing at water treatment plants and to old plants where addition of alum is problematic. It is recommended that the alum dosing regime be examined in cases where exceedances occur. A management systems approach to the operation of a water treatment plant should assist in the elimination of their exceedances.
No aluminium monitoring results were submitted by Mayo County Council or Laois County Council in 2001. This was also the case in 2000 and it is strongly recommended that both sanitary authorities commence aluminium monitoring immediately, as both operate treatment plants that use alum dosing as a treatment method. Limited sampling was also noted in Carlow (1 sample analysed) and Sligo (6 samples analysed). Extensive monitoring of group water schemes in Leitrim for aluminium indicated a significant number of exceedances of the standard. These exceedances were primarily due to elevated natural sources of aluminium in the source water, although a small number of schemes which took their water
6.00
5.00
4.00
3.00
2.00 centage of Samples Per 1.00
0.00 ≤0.4 ≤0.6 ≤1.0 >1.0
Band (mg/l) 1999 2000 2001
Figure 2-2: Distribution of Aluminium Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed). from public water supplies also had aluminium exceedances. These were due to excessive aluminium levels in the public water supply, which was provided to the group schemes for distribution.
11 Quality of Drinking Water in Ireland A Report For The Year 2001
Figure 2-3: Aluminium Compliance in Public Water Schemes by County.
12 Quality of Drinking Water in Ireland A Report For The Year 2001
There has been a disappointing drop in the number of sanitary authorities fully compliant with aluminium standard from 10 in 2000 to 7 in 2001. The rate of compliance with the standard was poor (and showed signs of worsening in many cases) in public water supplies in Cavan (71.6% compliance), Donegal (68.7%), Galway County (30.8%), Kilkenny (66.8%), Leitrim (56.2%), Longford (75.0%), South Tipperary (60.5%) and Wicklow (55.4%). The rates of compliance in public water supplies for each sanitary authority is shown on Figure 2-3.
2.3. AMMONIUM
Ammonia is generally present in natural waters, though in very small amounts, as a result of microbiological activity which causes the reduction of nitrogen-containing compounds. When present in levels above 0.1mg/l N, sewage or industrial contamination may be indicated. From the viewpoint of human health the significance of ammonia is marked because it indicates the possibility of sewage pollution and the consequent possible presence of pathogenic micro-organisms.
The number of samples analysed for ammonium increased in 2001 by over 5% to 8,214. A total of 4,767 and 3,381 samples were analysed for ammonium in public water supplies and group water schemes respectively, with the remainder taken from small private supplies. The compliance rate with the ammonium standard improved from 98.4% in 2000 to 99.0% in 2001 (Figure 2-4). When analysed in detail this improvement was a result of the halving of the number of exceedances in public water supplies from 29 in 2000 to 14 in 2001 and a reduction from 89 to 63 exceedances in group water schemes.
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-4: Ammonium Compliance over the Period 1999 to 2001.
Overall, there has been a reduction in the number of exceedances across all bands (Figure 2-5), including a very welcome reduction in gross exceedances. There was only one gross exceedance in public water supplies noted in 2001 (in Kerry). In group water schemes gross exceedances were noted in Carlow (2), Galway County (5), Longford (2) and Roscommon (8).
13 Quality of Drinking Water in Ireland A Report For The Year 2001
0.60
0.50
0.40
0.30
0.20 centage of Samples Per 0.10
0.00 ≤0.4 ≤0.6 ≤1.0 >1.0
Band (mg/l) 1999 2000 2001
Figure 2-5: Distribution of Ammonium Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
In summary, 31 of the 41 sanitary authorities that carried out ammonium monitoring in public water supplies in 2001 were fully compliant with the ammonium standard up from 25 in 2000. A similar improvement was noted in group water schemes. Of the 28 sanitary authorities that carried out ammonium monitoring in group water schemes in 2001, 20 were fully compliant (an increase from 17 in 2000). Overall, the improvement in the compliance rate, the reduction in the number of gross exceedances and the increase in the number of sanitary authorities fully compliant with the ammonium standard is a very welcome trend.
2.4. TOTAL & FAECAL COLIFORMS
Faecal coliforms originate in human and animal waste. Total coliforms include faecal bacteria and also other bacteria with similar properties which originate in soil and are non-faecal.
The risk of infection to consumers from drinking contaminated waters will vary depending on the numbers of pathogenic organisms present (i.e. the actual disease-causing organisms). The number of pathogens in a sewage-contaminated water depends on whether persons carrying the pathogens in their bodies (so- called "carriers") are present in the local population. As the latter is an unknown quantity, and as the positive identification of specific bacteria may be a very difficult task, an indirect approach is universally adopted. To ensure a high factor of safety when testing for coliform contamination, the practice has been to monitor indicator organisms. These, by definition, should be (a) easily detected and identified, (b) of the same origin as the pathogens (i.e. from the human or animal intestine), (c) present in far greater numbers than the pathogens (d) present whenever the pathogens are likely to be present and (e) able to show the same or better survival characteristics than the pathogens and, of course, they must not be in themselves pathogenic.
To date the universal indicator organisms have been coliforms, specifically Escherichia coli. These bacteria are of definite faecal origin (human and animal) and are excreted in vast numbers. Their presence
14 Quality of Drinking Water in Ireland A Report For The Year 2001
in a water supply is taken as proof that faecal contamination has occurred and it is therefore a definite indication of the risk that pathogens may be present. The absence of these faecal coliforms indicates strongly the probability that pathogens are absent.
Because some coliform organisms are able to grow in soil and are not of faecal origin a second analysis is carried out for the presence of total coliforms, giving an indication of the general level of microbiological contamination of a water.
There were 15,135 samples analysed for total coliforms in 2001 in public water supplies, representing a decrease in monitoring of just under 1% as compared to 2000. Overall compliance in public water supplies with the total coliform standard improved from 91.3% in 2000 to 92.6% in 2001. Compliance with the MAC was greater than 95% in 17 of the 41 sanitary authorities that carried out monitoring for total coliforms. Compliance with the total coliform standard was poor in Cork West (84.9%), Galway County (79.9%), Longford (81.2%) and Sligo County (81.8%).
With regard to group water schemes there were 4,151 samples analysed for total coliforms in 2001 which was similar to the previous year. The overall compliance rate with the total coliforms standard in group water schemes declined from 58.6% in 2000 to 56.8% in 2001 (Figure 2-6). The continuation of the downward trend in compliance with the total coliform standard in group water schemes is of much concern. In 2001, group water schemes in nine sanitary authorities had a compliance rate of less than 50%. These authorities were Carlow (33.3%), Cavan (35.3%), Cork West (37.5%), Kerry (44.0%), Leitrim (23.3%), Longford (31.1%), Mayo (32.7%), Sligo (0% - only 5 samples were analysed in 2001 all of which failed) and Westmeath (46.4%).
100
80
60
40 % Compliance
20
0 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-6: Total Coliforms Compliance over the Period 1999 to 2001.
15 Quality of Drinking Water in Ireland A Report For The Year 2001
As discussed previously, faecal coliforms is a more appropriate indicator of faecal contamination of a water supply than total coliforms. The test for faecal coliforms is invariably carried out in tandem with the analysis for total coliforms and as such the number of samples analysed for faecal coliforms is almost identical to that of the total coliforms. Unlike the total coliforms where, if a sufficient number of samples have been analysed, up to 5% of the samples can contain total coliforms with the supply still being in compliance with the Regulations, the presence of a single faecal coliform in a water supply is in breach of the Regulations and therefore unaccceptable.
While the number of samples analysed for faecal coliforms in public water supplies was similar to the number of samples analysed for total coliforms the compliance rate for faecal coliforms is significantly better. Overall compliance with the faecal coliform standard for public water supplies was 97.2% in 2001, which was up from 96.7% in 2000. This was due to a welcome reduction in the number of exceedances of the faecal coliform standard, from 510 exceedances in 2000 to 422 exceedances in 2001, while the number of samples analysed in each year was similar. Of the 41 sanitary authorities that carried out monitoring for faecal coliforms in public water supplies, 10 were fully compliant with the standard in 2001 (up from 9 in 2000).
Similarly, there was an improvement in the faecal coliform compliance rate in group water schemes in 2001. Although, an almost identical number of samples were analysed for faecal coliforms in 2001 as compared to the previous year, there was a reduction in the number of faecal coliform exceedances from 1,206 in 2000 to 1,073 in 2001. The reduction in exceedances of the standard resulted in an improvement in the overall compliance rate from 70.8% in 2000 to 74.1% in 2001. While this improvement is a welcome development, compliance with the faecal coliform standard in group water schemes remains poor. In 2001, group water schemes in 11 sanitary authority areas had a compliance rate of less than 75%. These authorities were Cavan (69.4%), Cork West (50.0%), Donegal (71.6%), Kerry (64.0%), Leitrim (32.5%), Longford (66.2%), Mayo (55.6%), North Tipperary (74.1%), Roscommon (66.6%), Sligo (0% - see explanation above) and South Tipperary (56.3%). The trend in compliance with the total coliform standard over the three year period 1999 to 2001 is illustrated in Figure 2-7 while the distribution in
100
90
80
70 % Compliance
60
50 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-7: Faecal Coliform Compliance over the Period 1999 to 2001.
16 Quality of Drinking Water in Ireland A Report For The Year 2001
exceedances across the bands is shown in Figure 2-8. Compliance with the faecal coliform standard in both public water supplies and group water schemes in 2001 on a county basis is shown in Figures 2-9 and 2-10 respectively.
7.00
6.00
5.00
4.00
3.00
centage of Samples 2.00 Per 1.00
0.00 ≤20 ≤200 ≤500 >500
Band (No./100ml) 1999 2000 2001
Figure 2-8: Distribution of Faecal Coliform Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
As stated in previous years reports, the single most important characteristic of drinking water, as far as the general health of the Irish public is concerned, is the bacteriological quality of the water. The majority of exceedances of the drinking water standards are due to the presence of coliforms. Of particular concern is the presence of faecal coliforms in a water supply which as previously stated is taken as a definitive indication that faecal contamination of the water supply has occurred. Table 2.2 presents an analysis of the serious incidents of faecal coliforms (i.e. >20cfu/100ml) in public water supplies in 2001. Although there has been a welcome decrease in the number of serious incidents from 66 in 2000 to 52 in 2001, it is of great concern that follow-up samples were not taken within seven days in the case of 25 of these incidents. Indeed, in 5 of the supplies that had serious faecal contamination incidents, there was no record of a follow up sample being taken in 2001. These supplies were Inch/Youghal (Cork South), Ardagh, Carrick Old, Cranford and Lifford Old (all Donegal). Although these supplies were all small public water supplies (the largest of which served 600 persons), it is nonetheless unacceptable that follow up monitoring was not conducted following the detection of serious faecal contamination.
Table 2-2: Analysis of Serious Faecal Coliforms Incidents in Public Water Supplies in 2001.
Summary of Serious Faecal Coliform Incidents No. of Incidents Pop. Affected Serious Faecal Coliform Incidents (>20/100ml) 52 81,325 persons
Serious Incidents not Resampled within 7 days 25 19,705 persons Serious Incidents not Resampled in 2001 5 781 persons
17 Quality of Drinking Water in Ireland A Report For The Year 2001
Figure 2-9: Faecal Coliform Compliance in Public Water Supplies by County.
18 Quality of Drinking Water in Ireland A Report For The Year 2001
Figure 2-10: Faecal Coliform Compliance in Group Water Schemes by County.
19 Quality of Drinking Water in Ireland A Report For The Year 2001
2.5. COLOUR
Natural colour reflects the presence of complex organic molecules derived from vegetable (humic) matter such as peat, leaves, branches and so on. Its effect can be enhanced by the presence of suspended matter but this is normally eliminated in the analysis by filtration. Therefore, the more vegetable matter there is in water the greater the colour. Exceptionally, natural colour may arise from the presence of colloidal iron/manganese in a water but organic matter is almost always the cause.
Objections to high colour are generally made on aesthetic rather than health grounds. Consumers are reluctant to drink water, however safe, which has a strong colour. The 1998 EU Drinking Water Directive in contrast to its 1980 predecessor, did not set a quantitative standard for colour, effectively leaving the matter to the reactions of consumers.
Nonetheless, it must be noted that the presence of colour on a persistent basis in a water which is then disinfected by chlorination is highly undesirable. This is because of the readiness with which the colour- causing substances react with the added chlorine, giving rise to the presence of trihalomethanes. The latter compounds are a potential hazard to public health and will be discussed later in this chapter.
Because of its origin in vegetable matter the degree of colour in a water will vary. The highest colour levels in rivers occur during floods, especially the first flood after a dry season when accumulated deposits of decaying leaves and debris are swept up into the heavy flow.
In 2001, there were 13,009 samples analysed for colour of which 9,351 and 3,554 were from public water supplies and group water schemes respectively with the remainder from small private supplies. This level of monitoring indicates that the large increase in monitoring seen in 2000 was maintained. The overall compliance rate with the colour standard has decreased again slightly in 2001 from 93.1% in 2000 to 92.1% in 2001. The reason for this drop, as illustrated on Figure 2-11, is due to the increase in exceedances in group water schemes. Compliance in public water supplies actually improved in 2001.
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-11: Colour Compliance over the Period 1999 to 2001.
20 Quality of Drinking Water in Ireland A Report For The Year 2001
In public water supplies the overall compliance rate improved from 94.1% in 2000 to 94.6% in 2001 (Figure 2-11). However, just 5 of the 41 sanitary authorities were fully compliant with the colour standard. Compliance with the standard was poor in Cavan (78.7%), Monaghan (80%) and Sligo Borough (68.8%).
By contrast compliance with the colour standard in group water schemes deteriorated in 2001 from 90.5% in 2000 to 85.4% in 2001. While compliance was poor in general, it was particularly so in Cavan (70.6%), Donegal (61.3%), Leitrim (46.3%), Mayo (78.5%) and Monaghan (48.9%). In Leitrim, 24 of the exceedances were gross (i.e. >150 mg/l Pt/Co). The distribution of exceedances of both public water supplies and group water schemes are shown on Figure 2-12.
6.00
5.00
4.00
3.00
2.00 centage of Samples Per 1.00
0.00 ≤40 ≤80 ≤150 >150
Band (mg/l Pt/Co) 1999 2000 2001
Figure 2-12: Distribution of Colour Exceedances over the period 1999 to 2001 (measured as a percentage of the total samples analysed).
2.6. FLUORIDE
Fluoride arises almost exclusively from fluoridation of public water supplies and from industrial discharges, although it occurs naturally in quite rare instances. Health studies have shown that the addition of fluoride to water supplies in levels above 0.6mg/l F leads to a reduction in tooth decay in growing children and that the optimum beneficial effect occurs around 1.0 mg/l2. At levels markedly over 1.5mg/l an inverse effect occurs and mottling of teeth (or severe damage at gross levels) will arise. For this reason there is a constraint on fluoride levels, the effects of which vary with temperature. In recent years some authors have questioned the practice of adding fluoride to drinking water on ethical and medical grounds. This important debate has been addressed by the Forum on Fluoridation set up by the Minister for Health and Children in 2000, which published its findings in September 2002.
The fluoride levels in fluoridated public water supplied in Ireland are legally restricted to the range 0.8- 1.0 mg/l. In making the 1988 Drinking Water Regulations the then Minister for the Environment fixed 1.0 mg/l F [1,000 µg/l F] as the MAC. This value is lower than the MAC set in both the 1980 and the revised 1998 EC Drinking Water Directives, which set a value of 1.5 mg/l. The level of fluoride monitoring in 2001 remained similar to that in 2000 with 7,314 samples analysed in public water supplies and 248
2 A new target dose of between 0.6 and 0.8 mg/l F, with a target of 0.7 mg/l, was proposed by the Forum on Fluoridation in September 2002 at which it was considered that the optimal beneficial effects occur.
21 Quality of Drinking Water in Ireland A Report For The Year 2001
samples analysed in group water schemes. The lack of monitoring in group water schemes is due to the fact that while it is a legal requirement for public water supplies to be fluoridated there is no such obligation on the sanitary authority in respect of group water schemes. Therefore, fluoride is generally not added to group water schemes, thus rendering monitoring of fluoride irrelevant in such cases. The overall compliance rate with the fluoride standard was 95.5% in 2001, which represents an improvement from 94.0% in 2000. This trend is shown for public water supplies and group water schemes in Figure 2-13. Of the 41 sanitary authorities that carried out monitoring for fluoride seven were fully compliant with the standard. However, compliance with the fluoride standard was problematic in Cavan (84.9%), Ennis (81.0%), Limerick County (83.3%), Louth (73.7%) and Mayo (84.3%).
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-13: Fluoride Compliance over the Period 1999 to 2001.
In previous years the majority of exceedances of the fluoride standard have tended to be in the second band of exceedances (i.e. between 1050 µg/l and 1250 µg/l). In 2001, the distribution of exceedances was similar (Figure 2-14). There were just 4 gross exceedances (i.e. >1,500 µg/l) of the fluoride standard in public water supplies in 2001. These exceeded the EU Drinking Water Directive standard and were found in Kilkenny (1), Laois (2) and South Tipperary (1). Gross exceedances were also recorded in group water schemes in Clare (4 exceedances) and Laois (1 exceedance).
22 Quality of Drinking Water in Ireland A Report For The Year 2001
5.00
4.00
3.00
2.00 centage of Samples
Per 1.00
0.00 ≤1050 ≤1250 ≤1500 >1500
Band (mg/l) 1999 2000 2001
Figure 2-14: Distribution of Fluoride Exceedances over the period 1999 to 2001 (measured as a percentage of the total samples analysed).
In last years report, comments were made in relation to the measurement of background levels of fluoride in raw waters. While monitoring for 2001 shows an overall improvement in compliance with the fluoride standard, it is thought prudent that the comments be repeated.
The Irish fluoridation legislation [Health (Fluoridation of Water Supplies) Act 1960] requires that background levels should be taken into account when dosing water with fluoride and it is undoubtedly the case that this was done as each successive water supply began to be fluoridated. However, continued sampling over successive seasons is required in order to establish a valid background variation in fluoride for a water source, but it would seem that this has not been carried out, and that, over time, the whole issue of background fluoride levels has been overlooked.
Sanitary authorities are required under the 1989 Surface Water Regulations (S.I. No. 294 of 1989) to monitor their surface raw water sources for a variety of parameters, including fluoride, for which standards are laid down. Thus, authorities with such sources, should have available a body of background information on fluoride, updated regularly as results of continued implementation of the Surface Water Regulations. However, it appears that these data on fluoride are not being considered by those engaged in the fluoridation of drinking water. This is an oversight which should be remedied forthwith, and action should also be taken to institute background data collection on fluoride levels in ground water sources.
Although available data are far from definitive, there is evidence to suggest that in many waters background levels of up to 200 µg/l of fluoride have been reported, and as such the determination of the accurate background levels would assist in bringing many offending supplies into full compliance. Accordingly, the sanitary authorities are urged to make parallel determinations of fluoride in raw and final fluoridated waters in order to establish the background conditions, and to ensure that their dosages are adjusted appropriately downwards.
It is important to stress that the above discussion is driven by the need to meet the legal requirements of
23 Quality of Drinking Water in Ireland A Report For The Year 2001
the 1988 Regulations rather than to alleviate any perceived health hazards from fluoridated drinking waters. The important issues surrounding the fluoridation of drinking water supplies and public health have been addressed by the Forum on Fluoridation set up by the Minister for Health and Children in May 2000 which reported on its findings in September 2002. A summary of the main findings and recommendations of the forum are presented in detail in section 5.4.
2.7. HEAVY METALS
Heavy metals are a very important category of drinking water parameters and comprise principally antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel, selenium, silver, tellurium, thallium, tin, titanium, uranium, vanadium and zinc. Arsenic, though non- metallic, is included for convenience as it is toxic and is generally referred to as a constituent of this group. The term "heavy metals" is rather inaccurate and, indeed could be misleading. It arises from the high atomic weights of several metals in the broad group, although other metals in the same group have low atomic weights. Nonetheless, the term is both widely current and a useful descriptor. In common with previous years reports, compliance is based on a discussion of the four metals that are most commonly analysed (i.e. copper, zinc, lead and cadmium).
Sources of heavy metals include effluent discharges, distribution piping, or geological formations. Heavy metals are toxic to humans (to a greatly varying degree depending on the metal) and, to a lesser extent, fish. They bioaccumulate in fish and other animal tissue and are hence liable to enter the human food chain.
The overall level of monitoring of heavy metals increased significantly in 2001 with 8,615 tests analysed for metals. This represents an increase of over 80% in the amount of monitoring as compared with 2000. However, a breakdown of the monitoring into public water supplies and group water schemes indicates that there has been a 150% increase in monitoring of the former to 7,431 samples while the latter has actually decreased by 38% to 1,031 samples. There were 16 exceedances in public water supplies (of which 4 were due to lead, 11 due to copper and 1 due to zinc) and 5 in group water schemes (of which 2 were due to lead and 3 due to copper) in 2001. Compliance with the metals standards between 1999 and 2001 is shown in Figure 2-15.
24 Quality of Drinking Water in Ireland A Report For The Year 2001
100
98
96
94 % Compliance
92
90 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-15: Heavy Metal Compliance over the Period 1999 to 2001.
2.8. IRON
Iron is present in significant amounts in soils and rocks, principally in insoluble forms. However, many complex reactions which occur naturally in ground formations can give rise to more soluble forms of iron which will therefore be present in water passing through such formations. Appreciable amounts of iron may therefore be present in ground waters. Serious problems can be caused in drinking water supplies by the presence of iron. Problems with iron are primarily aesthetic, as the soluble (reduced) ferrous (Fe++) iron is oxidised in air to the insoluble ferric (Fe+++) form, resulting in colour or turbidity (or, in severe cases, precipitate formation). Laundry may become stained if washed in water with excessive iron and vegetables may become discoloured on cooking. Taste problems may also occur. When waters rich in iron are used to make tea (in which tannins are present) there may be a reaction giving rise to off-colours which may in severe cases resemble that of ink.
Iron, along with manganese, is an abundant naturally-occurring metal which can exist in soluble and insoluble states. Where iron occurs in the larger, treated public supplies it almost invariably arises from distribution mains made of the metal, and concentrations tend to be not greatly above the MAC. In smaller supplies - the minor public ones and especially the group schemes - its presence is both more frequent and more pronounced. Such waters are very largely derived from ground waters and the iron is present in the geological composition of the source area.
The problem with iron is that, in the ground, it exists in a reduced form which is soluble, and a well water when drawn may be clear, uncoloured and pleasant in appearance. However, on exposure to air - especially with agitation by stirring or boiling - the iron converts to the insoluble oxidised form. The water turns brown; it may become turbid; or it even may deposit solids in the container or, worse (from the domestic viewpoint), on food being cooked or clothes being washed. Hence its designation as a "nuisance" parameter.
25 Quality of Drinking Water in Ireland A Report For The Year 2001
The significant increase in iron monitoring in 2000 was sustained in 2001, with a total of 6,098 and 2,087 samples analysed for iron in public water supplies and group water schemes respectively. The overall compliance rate for iron has improved from 90.1% in 2000 to 92.7% in 2001. This improvement was due to improved compliance with the iron standard in public water supplies where the compliance rate improved from 91.6% to 94.7%. However, the rate of compliance for iron in group water schemes actually deteriorated slightly in 2001, reversing the upward trend noted in compliance since 1998 (Figure 2-16).
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-16: Iron Compliance over the Period 1999 to 2001.
The majority of iron exceedances (Figure 2-17) were moderate (i.e. <800 µg/l). The majority of gross exceedances of the iron standard (i.e. >1,250 µg/l) were detected in group water schemes in Galway County (14) and Leitrim (22). Overall, compliance with the iron standard in public water supplies was poor in Monaghan (78.2%), Sligo Borough (56.3%) and Westmeath (75.0%) while in group water schemes compliance with the iron standard in Kerry (71.4%), Leitrim (56.7%) and Wicklow (40.0%) was also poor.
The WHO, in its 1993 guidelines for drinking water quality noted that even at a level of 2 mg/litre [2000 µg/l] iron did not pose a hazard to health and the metal has not been considered as a health-related parameter to date. However, some concern has recently been expressed by the medical profession regarding the presence of excess iron in drinking waters and studies on the question are in progress. It may be noted that the majority of exceedances in Irish drinking water are below 0.8 mg/l [800 µg/l] which, although much below the figure mentioned by the WHO, is still four times the legal limit.
26 Quality of Drinking Water in Ireland A Report For The Year 2001
6.00
5.00
4.00
3.00
2.00 centage of Samples Per 1.00
0.00 ≤400 ≤800 ≤1250 >1250
Band (ug/l) 1999 2000 2001
Figure 2-17: Distribution of Iron Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
2.9. MANGANESE
As with iron, manganese is found widely in soils and is a constituent of many ground waters. Similar to iron it may be brought into solution in reducing conditions and the excess metal will be later deposited as the water is reaerated. The general remarks for iron apply to manganese but the staining problems with this metal may be even more severe, hence the quite stringent limits. A second effect of the presence of manganese much above the limits is an unacceptable taste problem. There are no particular toxicological connotations. The objections to manganese, in common with iron, are aesthetic.
There was a significant increase of over 13% in the number of samples analysed for manganese in 2001, with 5,335 and 2,058 samples analysed in public water supplies and group water schemes, respectively. The overall compliance rate for manganese improved by 3.3% to 92.1% compliance in 2001. This improvement was due to an increase in the compliance rate in public water supplies, while the compliance rate in group water schemes actually decreased in 2001. In spite of a 50% increase in the number of samples analysed for manganese in public water supplies the number of exceedances actually dropped from 266 to 259 thereby resulting in an improved rate of compliance with the standard (95.2% in 2001 compared with 92.4% in 2000). By contrast, the compliance rate for manganese in group water schemes deteriorated from 87.2% in 2000 to 84.7% in 2001. (Figure 2-18).
27 Quality of Drinking Water in Ireland A Report For The Year 2001
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-18: Manganese Compliance over the Period 1999 to 2001.
The majority of manganese exceedances are either moderate or serious with only a small number of exceedances classified as gross (Figure 2-19). Compliance with the manganese standard was low in public water supplies in Meath (77.5%) and Monaghan (65.5%). The latter was due to high levels of manganese in the Monaghan Town supply which should be eliminated with the operation of the new treatment works for the town which commenced operating on 23rd July, 2002. Manganese exceedances were widespread in many group water schemes and this is due to the fact that many group water schemes use groundwater which often has elevated levels of manganese.
5.00
4.00
3.00
2.00 centage of Samples
Per 1.00
0.00 ≤100 ≤250 ≤500 >500
Band (ug/l) 1999 2000 2001
Figure 2-19: Distribution of Manganese Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
28 Quality of Drinking Water in Ireland A Report For The Year 2001
Manganese is primarily regarded as a "nuisance" parameter, that is, it poses problems of discoloration (both in the water and in laundry or cooking where the water is used) and, if concentrations are very high, it may cause problems with taste and turbidity. Because of these largely aesthetic and domestic effects its standard is quite low - 50 µg/litre. It has not been considered a hazard to consumer health but has been considered in detail by the WHO. That body has noted that its "acceptability threshold" is 0.1 mg/litre [100 µg/l], i.e. twice the standard in the Regulations, as the problems mentioned are either mild or imperceptible below 0.1 mg/l.
However, although the WHO considered that there was "no convincing evidence of toxicity in humans associated with the consumption of manganese in drinking water", there was a dearth of relevant studies. Available evidence suggested that some restriction was desirable and accordingly the WHO considered that "a provisional health-based guideline value of 0.5 mg/l [500 µg/l] should be adequate to protect public health."
It should be noted that a water with an exceedance level anywhere near this provisional WHO value would be most unpalatable.
2.10. NITRATE
Relatively little of the nitrate found in natural waters is of mineral origin, most coming from organic and inorganic sources. Organic sources include waste discharges and the main inorganic source is artificial fertilisers. However, bacterial oxidation and fixing of nitrogen by plants can both produce nitrates.
Interest is centred on nitrate concentrations for various reasons. Most importantly, high nitrate levels in waters to be used for drinking will render them hazardous to infants as they may induce the "blue baby" syndrome (methaemoglobinaemia). The nitrate itself is not a direct toxicant but is a health hazard because of its conversion to nitrite which reacts with blood haemoglobin to cause methaemoglobinaemia.
Eutrophication of water bodies due to excess nutrient loading is a major environmental issue in Ireland, as it causes adverse impacts on fish and other biota, on abstraction of waters for industrial or domestic use and on recreational activities. Nitrates may cause particular eutrophication problems in estuaries, arising there primarily as a result of sewage and industrial discharges and due to losses from agricultural land. The presence of nitrate in ground waters is cause for suspicion of sewage pollution or of excess levels of fertilisers or manure slurries spread on land.
Monitoring for nitrate in public water supplies remained approximately the same as in 2000 with 5,018 samples analysed in 2001. By contrast the level of monitoring for nitrate in group water schemes decreased slightly with 3,487 samples analysed in 2001. Compliance with the nitrate standard in public water supplies improved with just 33 exceedances of the standard compared with 38 in 2000. On the other hand, compliance with the nitrate standard in group water schemes decreased slightly with 44 exceedances in 2001 compared to 39 in 2000. Overall, 17 (2.2%) public water supplies and 24 (1.7%) group water schemes monitored had exceedances of the nitrate standard in 2001. Collectively, these 41 supplies serve 0.4% of the total population of Ireland. The net effect was that the overall compliance rate remained the same as in 2000 at 99.1% compliance (Figure 2-20).
29 Quality of Drinking Water in Ireland A Report For The Year 2001
100
98
96
94 % Compliance
92
90 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-20: Nitrate Compliance over the Period 1999 to 2001.
Monitoring results indicated that 31 of the 41 sanitary authorities that monitored for nitrate were fully compliant with the standard. The number of supplies with exceedances of the nitrate standard is shown on Figure 2-22. There were 7 gross exceedances of the nitrate standard in group water schemes in 2001. These were in Carlow (1), Cavan (2), Cork South (1), Kerry (1), Louth (1) and North Tipperary (1).
Nitrate exceedances were recorded in 17 public water supplies and 24 group water schemes in 2001. As described in the 2000 drinking water report nitrate exceedances were problematic in several small public water supplies in Kildare (Castlemitchell, Kilbeg/Kilberry, Kilmeade), Waterford and more specifically in the Glanworth supply in Cork North (where every sample submitted to the Agency since 1989 has exceeded the standard). Many of these nitrate exceedances are persistent. Ongoing problems in the affected supplies should be addressed as a priority.
30 Quality of Drinking Water in Ireland A Report For The Year 2001
0.50
0.40
0.30
0.20 centage of Samples
Per 0.10
0.00 ≤55 ≤65 ≤75 >75
Band (mg/l) 1999 2000 2001
Figure 2-21: Distribution of Nitrate Exceedances over the Period 1999 to 2001 measured as a percentage of the total samples analysed).
31 Quality of Drinking Water in Ireland A Report For The Year 2001
Figure 2-22: . Number of Public Water Supplies (PWS) and Group Water Schemes (GWS) with Nitrate Exceedances in 2001.
32 Quality of Drinking Water in Ireland A Report For The Year 2001
2.11. NITRITE
Nitrites exist normally in very low concentrations and even in wastewater treatment plant effluent levels are relatively low, principally because the nitrogen will tend to exist in the more reduced (ammonia; NH3) forms. Nitrite is an intermediate in the oxidisation of ammonia to nitrate, and this process can take place in soil. Sewage is a rich source of ammonia nitrogen, and as such waters which show an appreciable amount of nitrite are regarded as being of highly questionable quality and contamination with sewage is suspected. Levels in unpolluted waters are normally low, below 0.03 mg/l NO2-. Values greater than this may indicate sewage pollution. The role of nitrite in methaemoglobinemia has been discussed in the previous section on nitrate.
The numbers of samples analysed for nitrite was similar to the previous year. There were 4,360 and 3,089 samples analysed for nitrite in public water supplies and group water schemes in 2001, respectively. Compliance with the nitrite standard was high at 99.2% particularly in public water supplies where there were just 16 exceedances of the standard, giving a compliance rate of 99.6% in 2001. Of the 41 sanitary authorities that carried out monitoring of nitrite, 31 were fully compliant with the standard. Although there was a slight decrease in the compliance rate in group water schemes (from 99.0% in 2000 to 98.7% in 2001) 18 of the 28 sanitary authorities that undertook monitoring of nitrite in group water schemes were fully compliant in 2001. Compliance with the nitrite standard over the period 1999 to 2001 is shown in Figure 2-23.
100
98
96
94 % Compliance
92
90 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-23: Nitrite Compliance over the Period 1999 to 2001.
The majority of exceedances of the nitrite standard are in the gross band (i.e. >0.4 mg/l) as shown on Figure 2-24. The majority of these gross exceedances were detected in group water schemes in Galway County (6 gross exceedances) and Roscommon (8 gross exceedances). However, a large number of samples were analysed for nitrite in these sanitary authorities. Compliance with nitrite in all sanitary authorities was greater than 95% for both public water supplies and group water schemes.
33 Quality of Drinking Water in Ireland A Report For The Year 2001
0.35
0.30
0.25
0.20
0.15
centage of Samples 0.10 Per 0.05
0.00 ≤0.15 ≤0.2 ≤0.4 >0.4
Band (mg/l) 1999 2000 2001
Figure 2-24: Distribution of Nitrite Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
2.12. ODOUR
Related to taste, a strong odour from a water for consumption may cause rejection on the part of the consumer. Its cause is normally dissolved volatile organic compounds, small concentrations of which may have significant organoleptic (i.e. associated with the senses) effects.
The majority of odour incidences arise from the presence of excess chlorine in the waters delivered to consumers. Care must be taken in interpreting odour non compliances because of the fact that chlorination is commonplace in public water supplies but is practised on a much reduced scale in the group water schemes.
Chlorine concentrations in drinking water, even when in excess, are not a direct hazard to the consumer. A water which had toxic chlorine levels would be so totally foul and thus utterly repugnant, it would be rejected out of hand by the consumer. Chlorine in levels above the working target concentration of 0.1-0.2 mg/l (there is no statutory level for chlorine in drinking water) would make the odour and taste of the affected waters aesthetically unacceptable.
There was a slight drop of 4% in the number of samples examined for odour. A total of 11,185 and 3,265 samples were examined for public water supplies and group water schemes in 2001 respectively. Overall compliance with the odour standard decreased from 96.3% in 2000 to 94.7% in 2001. Compliance in public water supplies (94.7%) is slightly higher than that of group water schemes (94.5%) as shown on Figure 2-25. The vast majority of odour non-compliance relate to the presence of chlorine in drinking water while the remainder are related to musty or stale odours. Poor compliance with the odour standard was noted in Dundalk (69.0%), Kildare (73.4%), Meath (71.3%) and Wicklow (73.7%).
34 Quality of Drinking Water in Ireland A Report For The Year 2001
100
98
96
94 % Compliance
92
90 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-25: Odour Compliance over the Period 1999 to 2001.
2.13. TASTE
As with odour, taste is a parameter which can lead to adverse consumer reaction. While astringent tastes can be caused by the presence of excessive amounts of metals or dissolved salts, there are often other more serious problems which arise in such cases. Purely organoleptic (i.e. associated with the senses) taste problems arise most commonly from algae and from phenols after chlorination. Decaying algae masses can release trace organic compounds (including phenol) into the water which produce offensive tastes after chlorination during treatment.
As with odour, there was a slight drop of 3% in the number of samples examined for taste. A total of 8,841 and 1,594 samples were examined in public water supplies and group water schemes in 2001 respectively. Overall compliance with the odour standard decreased from 98.0% in 2000 to 96.4% in 2001. Compliance in public water supplies (96.9%) is higher than that of group water schemes (93.7%). Similar to odour the vast majority of taste non-compliances relate to the presence of chlorine in drinking water, while the remainder are related to musty or stale tastes.
35 Quality of Drinking Water in Ireland A Report For The Year 2001
100
98
96
94 % Compliance
92
90 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-26: Taste Compliance over the Period 1999 to 2001.
2.14. pH pH is a measure of whether a liquid is acid or alkaline. The pH scale ranges from 0 (very acid) to 14 (very alkaline). The range of natural pH in fresh waters extends from around 4.5, for acid, peaty upland waters, to over 10.0 in waters where there is intense photosynthetic activity by algae. However, the most frequently encountered range is 6.5-8.0.
In waters with low dissolved solids, which consequently have a low buffering capacity (i.e. low internal resistance to pH change), changes in pH induced by external causes may be quite dramatic. Extremes of pH can affect the palatability of a water but the corrosive effect on distribution systems is a more urgent problem.
Overall, there was a 3% increase in the number of samples analysed for pH in 2001 with 9,616 and 3,587 samples analysed for pH in public water supplies and group water schemes respectively. The overall compliance rate with the pH standard rose marginally to 98.2%. However, while compliance with the pH standard improved marginally in public water supplies from 98.4% in 2000 to 98.6% in 2001 compliance decreased slightly in group water schemes from 97.8% in 2000 to 97.1% in 2001 (Figure 2-27).
36 Quality of Drinking Water in Ireland A Report For The Year 2001
100
98
96
94 % Compliance
92
90 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-27: pH Compliance over the Period 1999 to 2001.
A detailed breakdown of the exceedances of the pH standard (Figure 2-28) indicate that almost 90% of the pH exceedances were due to low pH. Compliance with the standard was less than 95% in public water supplies in Cork North, Cork South, Waterford and Wicklow, while poor compliance rates were recorded in group water schemes in the four areas mentioned above as well as Kerry and Leitrim. A discussion of the implications of the revised pH standard and its implications for compliance with the standard is included in section 2.19.
Although the pH of drinking water can be affected significantly by some elements of the treatment process, there is virtually always a compensating adjustment of the pH before the water is distributed. It follows that the great majority of pH exceedances reflect geographical influences on the source, usually causing a lowering of the pH rather than an increase. However, as noted in previous reports, the too-low pH levels found were not of any great consequence as far as the consumer is concerned, as pH is not a "problem" parameter.
37 Quality of Drinking Water in Ireland A Report For The Year 2001
1.20
1.00
0.80
0.60
0.40 centage of Samples Per 0.20
0.00 ≤5.5 <6.0 >9.0 ≥9.5
Band (mg/l) 1999 2000 2001
Figure 2-28: Distribution of pH Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
2.15. TRIHALOMETHANES
Trihalomethanes (THMs), as the name indicates, are derivatives of the simplest organic compound - methane, CH4 - in which three of the hydrogen atoms are substituted by halogen atoms. The principal halogens are fluorine (F2), chlorine (Cl2), bromine (Br2) and iodine (I2), but while many combinations are theoretically possible, the term trihalomethanes is applied to four specific compounds containing only chlorine and/or bromine as the halogen elements. The four compounds are chloroform (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3). As two of the four substances are chloroform and bromoform, the alternative designation haloforms is also quite frequently applied to the group.
Chlorine (or appropriate compounds of it) is undoubtedly the most important chemical used in water treatment in Ireland today as it has been in the past. Although it is a highly poisonous gas in its pure form and a powerful oxidising agent, chlorine in very dilute solution is a most effective agent for the disinfection of water. It is very efficient at destroying those bacteria which originate in human or animal waste and which cause wholly undesirable and dangerous contamination of drinking water.
As a powerful oxidising agent, chlorine also breaks down the complex Ð and inert Ð organic molecules which are the colouring agents, forming smaller, reactive entities. These entities react with chlorine (and with bromine derived from the oxidation by chlorine of bromide naturally present) to form the THM compounds, the most abundant of which is chloroform. There is thus a fairly straightforward relationship between the degree of colour in the water prior to chlorination and the quantities of THMs present following chlorination. If colour is present at the point of chlorination, THMs are likely be formed.
THM compounds are undesirable in drinking water for two reasons. Firstly the actual compounds themselves may pose a hazard to the health of the consumer if present in excessive amounts as chloroform is a suspected carcinogen. Secondly, the presence of the THM group may be an indicator of the possible
38 Quality of Drinking Water in Ireland A Report For The Year 2001
presence of other organic by-products of chlorination in trace amounts. The WHO advises that "In controlling trihalomethanes, a multistep treatment system should be used to reduce organic trihalomethane precursors, and primary consideration should be given to ensuring that disinfection is never compromised".
Trihalomethanes are not presently required to be monitored under the current Regulations and as such there is no current standard for the parameter. The 2000 Drinking Water Regulations introduce a standard of 100µg/l for Total Trihalomethanes in drinking water. However, an interim standard of 150µg/l takes effect from 1st January 2004 and is replaced by the standard of 100µg/l in 2007.
There was an increase of just under 8% in the number of samples analysed for trihalomethanes in 2001. A total of 880 and 433 samples were analysed by 26 different sanitary authorities for THM’s in public water supplies and group water schemes representing an increase of 3.2% and 17.7% respectively. As in the previous year, Cavan, Donegal and Galway County Councils as well as Galway City Council had extensive THM monitoring programmes in place in 2001. Of the samples analysed 69 (5.1%) exceeded the interim standard of 150 µg/l (effective from 1st January 2004) representing an increase from 34 (2.8%) in 2000. The standard (effective on 1st January 2007) of 100 µg/l was exceeded in 206 (15.7%) samples analysed up from 106 (8.7%) exceedances in 2000. Although relatively high levels of exceedances can be noted for certain sanitary authorities it must be remembered that many sanitary authorities have not yet commenced monitoring of THM’s and many others only have a minimal number of samples taken. Thus, more extensive monitoring of water supplies for THM’s must be carried out in order to obtain an accurate picture of THM compliance on a national basis. Particular attention must be paid to supplies where little or no treatment (apart from disinfection) of the water supplied occurs.
2.16. TURBIDITY
Turbidity in water arises from the presence of very finely divided solids, called colloids (which are not filterable by routine methods). The existence of turbidity in water will affect its acceptability to consumers and it will also affect markedly its utility in certain industries. The particles causing the turbidity may also interfere with the treatability of waters having adverse consequences for the disinfection process. As turbidity can be caused by sewage matter in a water there is a risk that pathogenic organisms could be shielded by the particulate matter and hence escape the action of the disinfectant.
The numbers of samples analysed for turbidity in 2001 was similar to the previous year with 8,750 and 3,497 samples analysed in public water supplies and group water schemes, respectively. However, the overall compliance rate dropped substantially from 97.9% in 2001 to 96.4% in 2000. This is due to a drop in both the compliance rate in public water supplies and group water schemes (Figure 2-29).
39 Quality of Drinking Water in Ireland A Report For The Year 2001
100
95
90
85 % Compliance
80
75 Public Water Supplies Group Water Schemes
1999 2000 2001
Figure 2-29: Turbidity Compliance over the Period 1999 to 2001.
The majority of turbidity exceedances (67% of exceedances) were moderate and there was a halving of the number of gross exceedances of the turbidity standard (Figure 2-30). Compliance with the turbidity standard was poor in public water supplies in Cavan (68.4%) while for group water schemes compliance was poor in Cavan (55.3%), Kerry (33.3%), Leitrim (78.1%) and Sligo County (80.0%).
2.5
2.0
1.5
1.0 centage of Samples
Per 0.5
0.0 ≤20 ≤40 ≤50 >50
Band (NTU's or mg/l SiO2) 1999 2000 2001
Figure 2-30: Distribution of Turbidity Exceedances over the Period 1999 to 2001 (measured as a percentage of the total samples analysed).
40 Quality of Drinking Water in Ireland A Report For The Year 2001
2.17. CRYPTOSPORIDIUM
Cryptosporidium is a small (microscopic) protozoan parasite present in faecal material that has pathogenic effects in both children and adults when it enters the gastrointestinal tract and causes an infection termed cryptosporidiosis. Cryptosporidiosis can cause fever, stomach upsets, weight loss and diarrhoea and can be fatal in the young and old and those with weakened immune systems. Cryptosporidium is protected by an outer shell (cyst) permitting it to survive for long periods outside the body. The cyst is very resistant to destruction by chlorine and other disinfectants, although it is destroyed by boiling water. Outbreaks of cryptosporidiosis caused by its presence in drinking water supplies have been reported in the US and other countries.
There are no standards in current Irish legislation concerning Cryptosporidium in drinking water although a circular letter was issued by the Department of Environment and Local Government (L7/98) which addresses the issue of monitoring of water supplies for Cryptosporidium oocysts. This circular states that water supplies should be monitored for Clostridium perfringens. Where the level of Clostridium perfringens exceeds 0 per 100 ml, consideration should be given to monitoring for Cyrptosporidium in raw and treated water. Based on monitoring submitted to the Agency in 2001, a total of 126 samples were analysed for Clostridium perfringens of which 20 samples in 11 supplies exceeded the guideline of 0 per 100 ml. Of these 11 supplies, monitoring for Cryptosporidium was subsequently carried out in just 2 supplies.
The 2000 Regulations which come into force on January 1st 2004 contain a general provision that water "is free from any micro-organisms and parasites and from any substances which, in numbers or concentrations, constitute a potential danger to public health". There is also an indirect requirement for monitoring of Cryptosporidium in the new Regulations. Where levels of Clostridium perfringens are detected in excess of the standard of 0 per 100 ml, "the supply shall be investigated to ensure that there is no potential danger to human health arising from the presence of pathogenic micro-organisms e.g. Cryptosporidium".
In the UK there is a treatment standard of 1 oocyst per 10 litres which, it must be stressed, is a not a health related standard due to the wide variation in susceptibility throughout the population. In Northern Ireland there is a ‘formal notification threshold’ of 1 oocyst per 10 litres and an ‘alert level’ of 0.1 oocyst per 10 litres. Experience in the UK has shown that there is evidence that where outbreaks of cryptosporidiosis have occurred the concentrations of oocysts were in excess of 1 oocyst per 10 litres. The UK approach to risk reduction is centred on the requirement to install and operate physical barriers to optimise removal of Cryptosporidium from water supplies. The approach in Northern Ireland and Scotland has been one of risk assessment whereby the most vulnerable treatment works are identified and prioritised for upgrading to suitable standards. In April and May 2000, three outbreaks of cryptosporidiosis were reported in Northern Ireland where at least 476 confirmed cases of cryptosporidiosis were reported (Glaberman et al., 2002).
A limited number of samples were analysed for Cryptosporidium in public water supplies in 2001. A total of 387 samples were analysed, the vast majority of which were from the 4 Dublin local authorities (346 samples). The remaining samples were taken from public water supplies in Ennis, Galway City, Leitrim and Offaly. As discussed earlier there are no legal limits in Ireland for Cryptosporidium in drinking water. However, if the results are discussed in the context of the ‘formal notification threshold’ and ‘alert levels’ that apply in Northern Ireland, no samples exceeded the ‘formal notification threshold’ while three samples exceeded the ‘alert’ threshold. It is difficult to interpret these results on a national basis due to the limited geographical spread of the samples.
41 Quality of Drinking Water in Ireland A Report For The Year 2001
The National Disease Surveillance Centre (NDSC, 2002) reported that two waterborne outbreaks of cryptosporidiosis were reported to the centre in 2001. The first was linked to a swimming pool with four confirmed and two possible cases. The second related to a small outbreak on a family farm served by a private well where two cases were reported. It is recommended that monitoring for Cryptosporidium be initiated on a more widespread basis with particular attention focusing on surface water supplies that have no treatment except disinfection. In light of the outbreak of cryptosporidiosis in Mullingar in 2002 it is recommended that a risk assessment be carried out on Irish drinking water treatment plants to identify those water supplies most at risk and to avoid a recurrence of the 2002 outbreak.
A draft report on waterborne cryptosporidiosis has been prepared by the National Disease Surveillance Centre (NDSC, 2002) which includes a number of recommendations in relation to Cryptosporidium surveillance, health board and local authority response, prevention and education about the risk associated with Cryptosporidium. In particular the Agency welcomes the recommendation in the draft report that a risk assessment approach be adopted in relation to Cryptosporidium and its possible presence in water supply. Increased monitoring and reporting of occurrence of the parasite will aid improved source protection and ultimately to a reduction in the occurrence of cryptosporidiosis.
There is an established relationship between elevated turbidity in a drinking water and the presence of Cryptosporidium oocysts. The 1988 Regulations have a standard of 4.0 NTU’s for turbidity in treated water which is replaced in the 2000 Regulations by "Acceptable to consumers and no abnormal change" with the following note; "In the case of surface water treatment, a parametric value not exceeding 1.0 NTU in the water ex treatment works must be strived for". Elevated levels of turbidity (above 1.0 NTU) may indicate the failure of the treatment process to remove turbidity particles and hence may indicate that Cryptosporidium oocysts have bypassed the treatment process. In the UK, the Bouchier, 1988 Report recommended that increases in turbidity in the final waters should trigger monitoring for Cryptosporidium (Bouchier, 1998).
2.18. NEW PARAMETERS INTRODUCED IN THE 2000 REGULATIONS
The European Communities (Drinking Water) Regulations, 2000 introduce comprehensive changes to the monitoring and maintenance of drinking water in Ireland. Details of the changes in terms of monitoring requirements and associated corrective action have already been discussed in Section 1.2 and the new parameters that will be required to be monitored in 2004 were outlined. In this section these new parameters are discussed in more detail and the level of monitoring required of these parameters is described. However, it must be noted that none of the parameters discussed below are required to be monitored until 1 January 2004 and hence absence of monitoring of these parameters at present does not indicate non-compliance or otherwise with the existing Regulations. Trihalomethanes have not been included in the discussion below as they were dealt with separately in section 2.15.
MICROBIOLOGICAL PARAMETERS
Enterococci
Enterococci originate in both animal and human faeces and are mainly used as an indicator of faecal pollution of a water supply although they do have some intrinsic pathogenic properties. As they can be reliably and easily determined their estimation is useful in clarifying the position in waters which show no E. coli but large numbers of coliform bacteria as a group. In the 1988 Drinking Water Regulations the relevant parameter was Faecal Streptococci but in the 2000 Regulations this has been replaced by the
42 Quality of Drinking Water in Ireland A Report For The Year 2001
broader parameter Enterococci. The ‘Parametric Value’ in the 2000 Regulations for Enterococci is 0 per 100 ml.
CHEMICAL PARAMETERS
Acrylamide
Acrylamide is a highly toxic carcinogenic substance that can be absorbed through unbroken skin. Polyacrylamide is used as a flocculant aid in water treatment and the polymeric substance inevitably contains traces of the acrylamide monomer. The WHO Guidelines note that "the most important source of drinking water contamination by acrylamide is the use of polyacrylamide flocculants that contain residual acrylamide monomer" and that "concentrations in drinking water can be controlled by product and dose specification". The ‘Parametric Value’ in the 2000 Regulations for acrylamide is 0.10mg/l.
Benzene
Benzene is a constituent of some petroleum products, it originates from industrial raw materials and is also used as a solvent. Benzene is a carcinogenic substance which affects the central nervous system. Pollution of water from industrial sources as well as emissions from motor vehicles account for most of the benzene in the aquatic environment. The ‘Parametric Value’ in the 2000 Regulations for benzene is 1.0 µg/l.
Benzo(a)pyrene
Benzo(a)pyrene is a synthetic organic compound formed by pyrolysis or combustion of organic materials. Benzo(a)pyrene is a carcinogenic and mutagenic substance which is highly undesirable in drinking water, although food is the main source of human exposure to this substance. The ‘Parametric Value’in the 2000 Regulations for benzo(a)pyrene is 0.010µg/l.
Bromate
Bromate occurs in water when bromide ions present in water are oxidised by ozone and some other oxidising agents (possibly chlorine). It is both carcinogenic and mutagenic. The ‘Parametric Value’ in the 2000 Regulations for bromate is 1.0 µg/l.
1,2-dichloroethane
1,2-dichloroethane is a synthetic organic solvent that is used in various industries. It is a toxic substance that causes a variety of ill-effects in humans including eye damage, dermatitis and narcotic effects. The ‘Parametric Value’ in the 2000 Regulations for 1,2-dichloroethane is 3.0 µg/l.
Epichlorohydrin
Epichlorohydrin is a synthetic chlorinated solvent. It is a toxic substance which is a strong skin irritant and which can cause kidney and other damage. The ‘Parametric Value’ in the 2000 Regulations for epichlorohydrin is 0.10µg/l.
43 Quality of Drinking Water in Ireland A Report For The Year 2001
Tetrachloroethene and Trichloroethene
Tetrachloroethene is a synthetic solvent used in the dry cleaning industry and for degreasing metals. It is a toxic solvent which can cause narcosis, dermatitis and ultimately fatal intoxication. Trichloroethene is also a synthetic solvent used in various industrial and manufacturing processes, in dry cleaning and for degreasing metals. It is a potential carcinogen and causes narcosis and effects similar to alcohol inebriation. The ‘Parametric Value’ in the 2000 Regulations for the sum of tetrachloroethene and trichloroethene is 10µg/l.
Vinyl Chloride
Vinyl chloride is a synthetic gaseous compound which polymerises very rapidly and is an important raw material in the manufacture of plastics. It is also used as a refrigerant. Vinyl chloride, being very volatile, can cause local frostbite if spilled on skin. It is also a suspected causative agent of liver cancer. The ‘Parametric Value’ in the 2000 Regulations for vinyl chloride is 0.50µg/l.
INDICATOR PARAMETERS
Clostridium perfringens
Clostridia are anaerobic spore-forming organisms, largely but not solely of intestinal origin. Their spores can survive in water much longer than organisms of the coliform group and they are much more resistant to disinfection. The WHO Guidelines note that "Their presence in disinfected waters may…indicate deficiencies in treatment and that disinfection-resistant pathogens could have survived treatment" and adds the observation that they are indicative of intermittent or remote contamination, with the caution that "Because they tend to survive and accumulate, they may be detected long after and far from the pollution and thus give rise to false alarms". The ‘Parametric Value’ in the 2000 Regulations for Clostridium perfringens is 0 per 100 ml.
2.19. PARAMETERS WITH REVISED STANDARDS IN THE 2000 REGULATIONS
The European Communities (Drinking Water) Regulations, 2000 introduce revised standards termed ‘parametric values’ for a number of parameters that already have standards in the 1988 Regulations. Table 2.3 details those parameters for which the standard has been revised in the 2000 Regulations (which become effective in 2004). An assessment is carried out comparing compliance with the current standard to that of the revised standard for each of the parameters listed.
44 Quality of Drinking Water in Ireland A Report For The Year 2001
Table 2-3: Parameters where the Standard has changed in S.I. No. 439 of 2000.
Parameter S.I. No. 81 of 1988 S.I. No. 439 of 2000 Comments EC (Quality of Water EC (Drinking Water) Intended for Human Regulations 2000 Consumption) Regulations Parametric Value 1988 MAC Antimony 10 µg/L 5.0 µg/L More stringent standard Arsenic 50 µg/L 10 µg/L More stringent standard Copper 3000 µg/L 2000 µg/L See text for comment Lead 50 µg/L 10 µg/L 25 mg/L - interim measure to be achieved by 2004 Nickel 50 µg/L 20 µg/L More stringent standard Nitrite 0.1 mg/L 0.5 mg/L Less stringent standard PAH 0.2 µg/L 0.1µg/L More stringent standard Boron 2000 µg/L 1.0 µg/L More stringent standard Sodium 150 mg/L 200 mg/L Less stringent standard pH 6.0 Ð 9.0 6.5 Ð 9.5 pH range has changed
Antimony
Antimony is a naturally occurring trace element used in the metal industry and in flame retardant materials. Antimony can occur naturally in water from weathering of rocks but is more likely to arise from industrial effluents. The standard in the 2000 Regulations for antimony is half that in the 1988 Regulations. A limited amount of sampling for antimony was carried out in 2001 with just 18 samples analysed for the parameter. All 18 samples analysed were below the limit of detection (i.e. <1 µg/l) and therefore all samples were in compliance. These samples also comply with the revised standard in the 2000 Regulations.
Arsenic
There has been a five-fold reduction in the standard from 50 µg/l to 10 µg/l. The same reduction in the standard has been the subject of an extensive review in the US which found that the reduction in the standard was justified (NAS, 2001), as inorganic arsenic is a documented human carcinogen. Arsenic is widely distributed in the earth’s crust and according to the WHO Guidelines "it is introduced into water through the dissolution of minerals and ores, from industrial effluents and from atmospheric deposition; concentrations in groundwater in some areas are sometimes elevated as a result of erosion from natural sources". As such arsenic may be a problem in groundwater sources where arsenic is a constituent of the geology.
The monitoring of arsenic carried out in 2001 was limited with just 31 samples analysed for the parameter in seven sanitary authorities. The majority of samples were taken in Clare and Waterford, therefore it is difficult to make an assessment of the impact of the revised standard. However, there was one exceedance of the current standard in Ballyogarty (53.1 µg/l). All other samples were below both the current and revised standard. In spite of the low levels detected it is likely that elevated levels of arsenic will be found in some supplies and the Agency urges sanitary authorities to carry out an assessment of their supplies to determine where compliance with the new arsenic standard is likely to be problematic.
45 Quality of Drinking Water in Ireland A Report For The Year 2001
Copper
The copper standard in the 2000 Regulations has been revised from the standard in the 1988 Regulations. In the 1988 Regulations there are two standards that relate to copper depending on where the sample has been taken. A MAC of 500 µg/L relates to samples taken at the outlet of pumping and/or treatment works and substations while a MAC of 3,000 µg/L relates to samples taken after the water has been standing in the piping and at the point where the water is made available to the consumer. The MAC of 2,000µg/L in the 2000 Regulations applies to a sample of water intended for human consumption obtained by an adequate sampling method (to be determined by the Minister) at the tap and taken so as to be representative of a weekly average value ingested by consumers and that takes account of the occurrence of peak levels that may cause adverse effects on human health. Consequently, a comparison between compliance with the current MAC and the revised standard is not possible.
Lead
The 1988 Drinking Water Directive, in line with WHO recommendations, sets a revised limit of 10 µg/l for lead Ð one fifth of the current MAC. As there is still a significant amount of lead piping in premises EU-wide it was appreciated that some Member States may have difficulty initially in meeting the revised lead limit, and the Directive takes account of this by setting an interim limit of 25 µg/l (which is effective from 1st January 2004 until 25th December 2013) whereupon the standard of 10 µg/l must be met. The new lead standard is described as a "Parametric Value" in line with the thinking of the WHO. This "Parametric Value" applies to a sample of water intended for human consumption obtained by an adequate sampling method at the tap and taken so as to be representative of a weekly average value ingested by consumers and that takes account of the occurrence of peak levels that may cause adverse effects on human health.
A comprehensive monitoring programme was undertaken in 2001 which consisted of 2,990 samples analysed for lead. The 18 exceedances of the interim lead standard were distributed among 12 different sanitary authorities, while the 70 exceedances of the long-term standard, which must be complied with by 2013, are found in 18 different sanitary authorities (Table 2.4). Therefore, the problems that compliance with the revised standard are likely to cause are not localised to any one area and are likely to require some action on the part of the majority of sanitary authorities.
Table 2-4: Compliance with the current, interim and long term lead standard.
Standard No. of Exceedances Percentage Compliance
1988 Regulations – 50 µg/l 5 99.83% 2000 Regulations – Interim Standard of 25 µg/l 18 99.39% 2000 Regulations Ð Long Term Standard – 10 µg/l 70 97.65%
Nickel
The primary sources of nickel are minerals and industrial wastes, although drinking water samples can be contaminated by nickel as a result of nickel coated tap fittings. Monitoring for compliance with the nickel standard in 2001 was extensive for the Dublin sanitary authorities but sparse elsewhere. Of the 1,053 samples analysed for nickel in 2001 over 95% were from the four Dublin sanitary authorities. As such, the assessment of compliance with the current and new standard (Table 2.5) is only valid for the Dublin supplies. As can be seen in Table 2.5, there was only a single exceedance of the current standard and just two exceedances of the revised standard.
46 Quality of Drinking Water in Ireland A Report For The Year 2001
Table 2-5: Compliance with the current and revised nickel standard.
Standard No. of Exceedances Percentage Compliance
1988 Regulations – 50 µg/l 1 99.91% 2000 Regulations – 20 µg/l 2 99.81%
Nitrite
Compliance with the current nitrite MAC in 2001 is discussed in detail in section 2.11. Extensive nationwide monitoring of nitrite was carried out in 2001 with 7,513 samples analysed for the parameter. Table 2.6 illustrates the effect the increasing standard will have on compliance with the nitrite standard based on results submitted for 2001.
Table 2-6: Compliance with the new current and revised nitrite standard.
Standard No. of Exceedances Percentage Compliance
1988 Regulations – 0.1 µg/l 58 99.23% 2000 Regulations – 0.5 µg/l 15 99.80%
The increase in the nitrite standard under the new Regulations will result in the majority of nitrite exceedances being eliminated with just 15 of the 7,513 samples analysed being above the revised standard.
PAHs
The standard for PAH’s appears to have been reduced from 0.2 µg/l to 0.1 µg/l. However, under the 1988 Regulations, PAH’s are defined as comprising six substances, namely; fluoranthene, 3,4- benzofluorathene, 11,12- benzofluorathene, 3,4-benzopyrene, 1,12-benzoperylene and indeno(1,2,3- cd)pyrene. Whereas, in the 2000 Regulations the definition for PAH’s does not include fluoranthene while 3,4-benzopyrene is listed as a separate parameter. Thus in the 2000 Regulations, PAH’s comprise the remaining four parameters listed above. Therefore, a comparison between the current and revised standard is not possible. Just 18 samples (17 of which were in County Clare) were analysed for PAH’s in 2001 thus militating against a meaningful assessment of the results on a national basis. Of these 18 samples analysed one exceeded the current standard.
Boron
Boron is a naturally occurring trace element that is also used in cleaning compounds and in alloys. Excessive levels of boron have been linked to problems in the human nervous system. A small number of samples (17) were analysed for boron in 2001 and all were significantly below both the current and revised standard.
Sodium
Sodium is an abundant natural constituent of rocks and soil and is always present in natural waters. Excessive intake can cause hypertension. The current standard of 150 mg/l has been increased in the 2000 Regulations to 200 mg/l. The effect of the new standard on the number of exceedances is shown in Table 2.7.
47 Quality of Drinking Water in Ireland A Report For The Year 2001
Table 2-7: Compliance with the current and revised sodium standard.
Standard No. of Exceedances Percentage Compliance
1988 Regulations Ð 150 mg/l 8 99.14% 2000 Regulations Ð 200 mg/l 3 99.68%
The net effect of the increase in the standard from 150 mg/l to 200 mg/l is the reduction in the number of exceedances from 8 to 3. As such compliance with the revised sodium standard in unlikely to be a problem. pH
Compliance with the current pH standard in 2001 is discussed in detail in section 2.14. The 2000 Regulations have resulted in a change in the pH band for acceptable drinking water. The current requirement is that pH must lie between 6.0 and 9.0 while the revised range will be between pH 6.5 and 9.5. The effect that this has on compliance is shown in Table 2.8.
Table 2-8: Compliance with the current and revised pH standard.
Standard No. of Exceedances Percentage Compliance
1988 Regulations Ð 6.0>pH<9.0 237 98.21% 2000 Regulations Ð 6.5>pH<9.5 630 95.25%
The new range of pH values that drinking water must lie between is likely to cause difficulties in a number of supplies. The results for 2001 indicate that the problem is likely to be meeting the requirement to be above pH 6.5 as 379 of the 630 exceedances lie in between pH 6.0 and 6.5. Sanitary authorities should investigate this potential problem prior to 2004 to ensure that they will be able to fully comply with the revised standard. Lime pH correction may be required in some treatment plants that use coagulation because of the lower levels of pH.
48 Quality of Drinking Water in Ireland A Report For The Year 2001
3. SANITARY AUTHORITY RESULTS
3.1. INTRODUCTION
This section of the report provides a general assessment of the results of monitoring undertaken by the various sanitary authorities during 2001. It deals with the adherence or otherwise of the Irish drinking water supplies to the requirements of the Regulations made by the Minister for the Environment. It is not a general treatment of the quality characteristics of such waters.
While the chapter endeavours to provide a general assessment of 22,453 samples analysed on a sanitary authority by sanitary authority basis in 2001 it is not possible to comment on every exceedance. Nonetheless, the EPA considers that any exceedance should not be overlooked or indeed condoned. Furthermore, there is a statutory requirement placed on sanitary authorities to take all reasonable steps to warn users of a water supply where there is an unacceptable risk to public health. As cited earlier in this report the EPA recommends that each sanitary authority should prepare and adopt documented procedures to deal in a structured manner with any exceedance of the Regulations. In summary, the comments (or lack thereof) in this chapter on an exceedance should not be construed as absolving an authority from its statutory duties.
It should also be noted when reading this chapter that some parameters of water quality are interrelated. For example, there is a link between total and faecal coliforms in that the former includes the latter. Similarly, colour, aluminium, iron, manganese and turbidity can show related effects. It may be useful, therefore to consider multiple exceedances in conjunction with one another rather than as discrete items of data.
Finally, the most important factor governing the extent of sampling required under the Regulations for the respective supplies is the volume supplied. There are no specific monitoring requirements for supplies of less than 200 m3/day volume, or populations below 1,000 persons, though this situation will change in 2004. Many group water schemes fall below both these thresholds and hence the Regulations allow that monitoring be undertaken at a frequency to be determined by the sanitary authority. Though these thresholds do not constitute a minimum below which no monitoring is required, the practice has been that most sanitary authorities monitor group schemes once per year and in some cases in three yearly cycles. Hence, while comments on the results for group water schemes and small private supplies are made below, it is clear that the small number of samples analysed for such supplies (in general) militate against making an informed assessment.
49 Quality of Drinking Water in Ireland A Report For The Year 2001
3.2. CARLOW
Summary Information Number of Public Water Supplies Monitored during 2001: 14 Estimated Population Served by Public Water Supplies Monitored during 2001: 33,335 persons Number of Group Water Schemes Monitored during 2001: 5 Estimated Population Served by Group Water Schemes Monitored during 2001: 1,204 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 11 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 5
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 93.3% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 100%
Assessment of the Monitoring Results for 2001
There were 14 public water supplies and 5 group water schemes in 2001 monitored by Carlow County Council in 2001 collectively supplying water to a population of just under 35,000 people.
Compliance with the faecal coliform standard in public water supplies was slightly below the national average in Carlow during 2001. There were three incidents of faecal coliform contamination of public water supplies during 2001. These were at Clonmore (9 samples of 42 analysed), Borris (1 sample of 13 analysed) and North Regional Water Supply Scheme (1 sample of 25 analysed). The Borris and North Regional Water Supply Scheme incidents were both minor in nature with follow up samples indicating a returns to compliance. The Clonmore exceedances were all reported over a three day period in July of 2001 with the supply returning to compliance within a week of the initial exceedance. None of the faecal exceedances in Carlow during 2001 were considered to be gross exceedances. It is noteworthy that of the 14 public water supplies in Carlow, 11 were fully compliant with the faecal coliform standard. All public water supplies in Carlow were fully compliant for fluoride, nitrite, odour, aluminium, iron and manganese standards. However, there was a notable lack of monitoring of aluminium, iron and manganese in public water supplies (only one sample of each analysed in 2001). This situation should be corrected and it is imperative that aluminium monitoring commence immediately in supplies where the treatment process involves alum dosing. There was one moderate exceedance of the nitrate standard reported (at Ballinkillen PWS which serves a population of 40), although a number of supplies reported values of nitrate close to the standard and should be examined in more detail.
Samples analysed from group water schemes were fully compliant with the faecal coliform standard in 2001, although only a very small number of samples were analysed (five samples). This was reportedly due to the difficulties in sampling created by the Foot and Mouth restrictions in early 2001. The small number of samples analysed militate against an assessment of the results as they may not be representative of the situation in group water schemes in Carlow as a whole. However, it is of concern that there was a high nitrate value reported in the Ballyloo GWS (80.3 mg/l) which is consistent with previous years results.
50 Quality of Drinking Water in Ireland A Report For The Year 2001
Review of the Period 1999-2001
The general quality of public water supplies in Carlow was satisfactory during the review period. The presence of faecal exceedances in public water supplies in Carlow in 2001 was regrettable, as compliance with the faecal coliform standard in Carlow in 2000 was 100%. The improvement in compliance with the nitrate standard in public water supplies is welcome although of concern is the fact that some of the supplies still report nitrate levels just below the standard. Most significant however, is the improvement in the compliance rate with the fluoride standard noted over the three year period. Compliance with the standard in both 1999 and 2000 was around 80%. This has dramatically improved in 2001 and all public water supplies were fully compliant with the fluoride standard in 2001.
Due to the limited monitoring of group water schemes in 2001, it is not possible to comment on trends for group water schemes over the three year period.
51 Quality of Drinking Water in Ireland A Report For The Year 2001
3.3. CAVAN
Summary Information Number of Public Water Supplies Monitored during 2001: 19 Estimated Population Served by Public Water Supplies Monitored during 2001: 24,186 persons Number of Group Water Schemes Monitored during 2001: 85 Estimated Population Served by Group Water Schemes Monitored during 2001: 17,055 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 14 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 59
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 97.1% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 69.4%
Assessment of the Monitoring Results for 2001
There were 19 public water supplies and 85 group water schemes monitored by the Cavan County Council in 2001 collectively supplying water to over 41,000 people.
Compliance with the faecal coliform standard in public water supplies was close to the national average, with 14 of the 19 public water supplies fully compliant with the faecal coliform standard. It is noteworthy that the large public water supplies (Cavan, Cootehill, Kingscourt, Bailieboro and Ballyjamesduff) were free of faecal coliform contamination. However, 5 of 31 samples analysed for the Virginia supply indicated the presence of faecal coliforms. The Virginia results indicate that there were 4 faecal contamination incidents in 2001, one of which was serious (46 faecal coliforms per 100 ml of sample). Compliance with the standard for colour and turbidity was problematic with 47 samples (out of 221 samples analysed) and 97 samples (out of 307 samples analysed) respectively in excess of the maximum allowable concentration. Compliance with the aluminium standard was problematic in the county during 2001. Ballyhaise (7 samples out of 9 samples analysed), Belturbet (9 samples out of 10 samples analysed) and Cavan (10 samples out of 28 samples analysed) regularly exceeded the maximum allowable concentration for aluminium. Although there has been an increase in the number of exceedances of the fluoride standard, many of the exceedances are marginally above the standard. An examination of the dosing regime and determination of background levels of fluoride may eliminate these marginal exceedances of the standard.
In relation to group water schemes, the limited monitoring conducted (one sample per scheme) indicate the overall bacterological quality to be poor with 26 samples out of 85 samples analysed for faecal coliforms indicating faecal contamination. On this basis, 59 of the 85 group water schemes were found to be in compliance. Gross contamination (i.e., > 20 cfu/100ml) was found in the Corran, and the Vale schemes. Many of the group schemes had values in excess of the standard for colour, iron and manganese. The Corraghy, Knocknashammer, Rakeevan and the Vale schemes were found to have nitrate levels in excess of the maximum allowable concentration.
Review of the Period 1999-2001
The general quality of public water supplies in Cavan remained satisfactory and of significance is the
52 Quality of Drinking Water in Ireland A Report For The Year 2001
improvement in the compliance rate for total and faecal coliforms in 2001 as compared to 2000. Regrettably there has been a reversal in the improvement in compliance with the aluminium standard with only 71.2% of samples in the county in compliance. This is a reduction of 10% in 2001 as compared to 2000 and returns the compliance levels to that of 1999. Contrary to the upward trend noted in 2000, compliance with the fluoride standard was down in 2001.
The quality of group water schemes by comparison was poor, as it has been in previous years. There was a further decrease in total coliform compliance (for the third year running) although there was a slight improvement in the faecal coliform compliance rate, which is nonetheless still below the national average.
53 Quality of Drinking Water in Ireland A Report For The Year 2001
3.4. CLARE
Summary Information Number of Public Water Supplies Monitored during 2001: 27 Estimated Population Served by Public Water Supplies Monitored during 2001: 51,482 persons Number of Group Water Schemes Monitored during 2001: 70 Estimated Population Served by Group Water Schemes Monitored during 2001: 12,660 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 23 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 67
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 97.8% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 95.6%
Assessment of the Monitoring Results for 2001
There were 27 public water supplies and 70 group water schemes sampled by the sanitary authority in 2001 and these collectively supply water to over 64,000 people.
Compliance with the faecal coliform standard in public water supplies was above the national average during 2001. The overall quality of drinking water in public water supplies in Clare was good in 2001 and showed an improvement for many of the parameters monitored as compared to 2000. Public water supplies were fully compliant with the standards for ammonium, nitrate, nitrite and turbidity as well as most of the metals. Full compliance was achieved with the faecal coliform standard for 23 of the public water supplies. All of the remaining 4 supplies that had exceedances were minor in nature (in all four cases only 1 faecal coliform was present per 100ml and was not found in subsequent samples). Compliance with the fluoride standard was 90% and it is noteworthy that the majority of exceedances were in the first six months of 2001. Compliance with the aluminium standard continued to be problematic with 27 (of 220 samples analysed) exceeding the standard although the majority of aluminium exceedances were moderate. It is recommended that the alum dosing be examined and adjusted accordingly. One exceedance of the lead standard was also noted in Lisdoonvarna (50.6µg/l).
The limited monitoring of group water schemes (one sample per scheme) indicated that drinking water was also of good bacteriological quality and demonstrated an improvement on the previous year. Full compliance, based on a sampling regime of 1 or 2 samples in 2001 (the limitations of which are discussed elsewhere), was achieved in 67 of the 70 group water schemes monitored. Of the three supplies (Bodyke, Kells/Corofin and Toonagh/Dysert) that had faecal coliform exceedances only the Toonagh/Dysert supply had a serious exceedance (>20 cfu per 100 ml) with the exceedances recorded in Bodyke and Kells/Corofin being moderate (i.e. <20 cfu per 100 ml). This high level of compliance on a county wide basis is commendable.
Review of the Period 1999-2001
The quality of drinking water in public water supplies was satisfactory during the review period and improved significantly over the three year period, in particular for fluoride (with compliance rates improving from 70% to 90%). Although the compliance rate for total and faecal coliforms decreased
54 Quality of Drinking Water in Ireland A Report For The Year 2001
slightly in 2001 it remained consistently high over the three year period.
The improvement in the quality of drinking water in group water schemes over the three year period is commendable and is particularly notable for total coliforms (compliance improved from 52% to 93%), faecal coliforms (from 64% to 96%) and for fluoride (from 60% to 73%). The high number of group water schemes apparently free from faecal contamination in 2001 is to be welcomed.
55 Quality of Drinking Water in Ireland A Report For The Year 2001
3.5. CLONMEL
Summary Information Number of Public Water Supplies Monitored during 2001: 2 Estimated Population Served by Public Water Supplies Monitored during 2001: 20,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 0 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 96.1% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There were two public water supplies, Glenary and Poulavanogue, monitored in 2001 by Clonmel Borough Council serving a population of approximately 20,000 people.
Compliance with the faecal coliform standard was slightly below the national average in Clonmel in 2001. The quality of drinking water was satisfactory with the exception of one exceedance of the faecal coliform standard in Glenary and two in Poulavanogue (one of which was gross). However, in all cases follow up samples were shown to be fully compliant with the standard. It is noteworthy that all samples analysed for ammonium, fluoride, nitrate, nitrite, pH and taste were fully compliant with the relevant standards.
Review of the Period 1999-2001
The quality of the drinking water in Clonmel remained consistently satisfactory during the review period. In addition, an improvement was noted in compliance with the fluoride standard with 100% compliance recorded in 2001 for the first time in the review period.
56 Quality of Drinking Water in Ireland A Report For The Year 2001
3.6. CORK CITY
Summary Information Number of Public Water Supplies Monitored during 2001: 1 Estimated Population Served by Public Water Supplies Monitored during 2001: 128,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 1 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There was one public water supply monitored in Cork City in 2001 serving a population of approximately 128,000 people.
Compliance with the faecal coliform standard was above the national average in 2001. The overall quality of the drinking water supply for Cork City was good in 2001. Total coliforms were present in 21 of the 441 samples analysed. However, none of these coliforms were of faecal origin and thus the presence of non-faecal coliforms is most likely indicative of minor problems in the distribution network. Moderate exceedances of the aluminium standard (4 of 88 samples analysed) were noted in 2001.
Review of the Period 1999-2001
The quality of drinking water during the review period was satisfactory and there was a continued improvement in compliance with the total coliform standard.
57 Quality of Drinking Water in Ireland A Report For The Year 2001
3.7. CORK (NORTHERN AREA)
Summary Information Number of Public Water Supplies Monitored during 2001: 59 Estimated Population Served by Public Water Supplies Monitored during 2001: 162,210 persons Number of Group Water Schemes Monitored during 2001: 15 Estimated Population Served by Group Water Schemes Monitored during 2001: 1,154 persons
Results of Microbiological Analysis Number of Public Water Supplies Monitored Free of Faecal Coliforms: 52 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 14
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 96.9% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 93.8%
Assessment of the Monitoring Results for 2001
There were 59 public water supplies and 15 group water schemes monitored in North Cork during the review period serving a population of over 160,000 people.
Compliance with the faecal coliform standard for public water supplies was close to the national average at 97% during 2001. However, of the 10 exceedances of the standard recorded all were moderate (i.e. <10 cfu per 100 ml), with the exception of one serious exceedance in the Mitchelstown Galtee water supply. These moderate exceedances were recorded in Bartlemy (1 of 2 samples analysed), Killally/Kilworth (3 of 7 samples analysed), Knockeragh (1 of 1 sample analysed), Mitchelstown Galtee (2 of 10 samples analysed), Monabricka (1 of 2 samples analysed), Moydelligo (1 of 2 samples analysed) and Rockchapel (1 of 3 samples analysed). All of the 59 public water supplies were fully compliant with the standards for ammonium, iron, nitrite, odour, taste and turbidity. Low pH values were a feature of several of the supplies in North Cork. Of much concern is the Glanworth supply which exceeded the nitrate standard on two occasions in 2001. The Glanworth supply has consistently exceeded the nitrate standard over the years with every sample analysed since 1989 exceeding the standard (the year the first report on the quality of drinking water in Ireland was published). This situation is unacceptable and the sanitary authority is urged to remedy this situation.
The bacteriological quality of group water schemes based on the one-off sampling regime was good with only 1 supply (Downing) having an exceedance of the faecal coliform standard. Of note is the 100% compliance with the nitrate standard as compared to the previous year where 5 supplies had exceedances of the nitrate standard. However, 3 of the 5 supplies that had exceedances in 2000 were not monitored in 2001.
Review of the Period 1999-2001
The overall quality of drinking water in public water supplies in 2001 was good and improved over the review period. Significant improvements have been made in compliance with the total (81% to 90%) and faecal (88% to 97%) coliform, nitrate (94% to 98%) and most notably aluminium (80% to 96%) standards. However, compliance with the pH standard (low pH) continues to be problematic and the Agency continues to have serious concerns over the quality of the Glanworth supply.
58 Quality of Drinking Water in Ireland A Report For The Year 2001
The quality of drinking water in group water schemes continues to be satisfactory and has improved over the review period in particular for faecal coliforms and nitrate.
59 Quality of Drinking Water in Ireland A Report For The Year 2001
3.8. CORK (SOUTH AREA)
Summary Information Number of Public Water Supplies Monitored during 2001: 60 Estimated Population Served by Public Water Supplies Monitored during 2001: 219,805 persons Number of Group Water Schemes Monitored during 2001: 32 Estimated Population Served by Group Water Schemes Monitored during 2001: 1,490 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 53 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 28
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 98.4% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 89.7%
Assessment of the Monitoring Results for 2001
There were 60 public water supplies and 32 group water schemes monitored during the review period serving a population of over 220,000 people.
Compliance with the faecal coliform standard in public water supplies was above the national average in South Cork during 2001. A high number of public water supplies in South Cork were free of faecal coliforms in 2001. However, 6 supplies were found to have faecal coliforms present in the water supplied. These were Ballingeary (1 sample of 4 analysed), Bilberry (1 sample of 2 analysed), Clonmacow (1 sample of 1 analysed), Dripsey Old (1 sample of 2 analysed), Glanmire Regional (1of 12 samples analysed), Inch/Youghal (1 sample of 2 analysed) and Macroom Urban (3 samples of 17 analysed). With the exception of the Inch/Youghal exceedance (40 cfu/100ml) all of the faecal exceedances were moderate (<20 cfu/100ml). The public water supplies in South Cork were fully compliant with the ammonium, metals, iron, manganese, odour and taste standards. However, as in 2000 there were notable problems with compliance with the aluminium standard in a number of supplies. There were several exceedances of the aluminium standard in 2001 most notably in Macroom Urban (9 samples of 15 analysed) and Youghal Regional (12 samples of 17 analysed) but also in Bandon Regional (3 samples of 18 analysed) and Midleton Urban (4 samples of 16 analysed). The former two supplies were noted in the previous years report and again the Agency urges that the addition of alum at these plants should be investigated and a programme of improvement put in place. One exceedance of the nitrate standard was noted in Roberts Cove in 2001.
The general quality of group water schemes was satisfactory and showed some improvement over the previous year. However, faecal coliforms were found in 4 of the 31 group water schemes monitored. High levels of nitrates were found in three group water schemes also.
Review of the Period 1999-2001
The quality of drinking water in public water supplies was satisfactory during the review period with slight improvements recorded in compliance with the coliforms (both total and faecal) and nitrates. The low level of compliance with the aluminium standard (due to the schemes mentioned above) is of concern and showed no improvement over the review period. The quality of water supplied by group water schemes was also satisfactory and improved substantially over the review period. In particular, the improvement in faecal coliform compliance from 70% in 1999 to 90% in 2001 is to be welcomed.
60 Quality of Drinking Water in Ireland A Report For The Year 2001
3.9. CORK (WEST AREA)
Summary Information Number of Public Water Supplies Monitored during 2001: 31 Estimated Population Served by Public Water Supplies Monitored during 2001: 41,450 persons Number of Group Water Schemes Monitored during 2001: 7 Estimated Population Served by Group Water Schemes Monitored during 2001: 248 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 22 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 4
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 92.8% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 50.0%
Assessment of the Monitoring Results for 2001
There were 31 public water supplies and 7 group water schemes monitored during the review period serving a population of over 41,000 people.
Compliance with the faecal coliform standard in public water supplies was below the national average in West Cork in 2001. Overall, the general quality of drinking water in public water supplies in Cork West was satisfactory. However, there was some concern over the number of public water supplies (9) that had incidents of faecal contamination at different stages throughout the year. Of particular concern was the Cahermore and Kealkill supplies. In the Cahermore supply, all 4 samples analysed were found to contain coliforms (in three of these samples the coliforms were found to be of faecal origin) while in the Kealkill supply 3 samples (of 6 analysed) were found to contain coliforms (which were all found to be of faecal origin). Isolated incidents of low levels of faecal contamination were also found in the Ardigoole, Bantry New, Drinagh, Leap, Skibbereen, Snave and Tarelton public water supplies. Also of concern were the elevated levels of nitrates found in the Castletownkinnagh supply. All 3 samples analysed for nitrate were found to be above the standard. An analysis of previous years monitoring results indicated that nitrate exceedances have been noted in the supply since 1999. The cause of these excessive levels of nitrates should be investigated and the relevant corrective action taken, given the potential implications for human health.
A limited programme of monitoring of the small number of group water schemes in Cork West was undertaken in 2001. Almost half of the supplies were found to contain coliforms of faecal origin.
Review of the Period 1999-2001
The quality of drinking water from public supplies remained satisfactory during the review period although an improvement in the compliance with the faecal coliform standard in both public and group supplies would be a welcome development. In 2001 there was a significant improvement in compliance with the fluoride standard. Compliance with the fluoride standard in 2001 was 95% compared to 86% in 2000.
61 Quality of Drinking Water in Ireland A Report For The Year 2001
3.10. DONEGAL
Summary Information Number of Public Water Supplies Monitored during 2001: 56 Estimated Population Served by Public Water Supplies Monitored during 2001: 103,960 persons Number of Group Water Schemes Monitored during 2001: 21 Estimated Population Served by Group Water Schemes Monitored during 2001: 5,494 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 41 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 8
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 97.0% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 71.6%
Assessment of the Monitoring Results for 2001
There were 56 public water supplies and 21 group water schemes monitored in 2001 by Donegal County Council serving a population of approximately 110,000 people.
Compliance with the faecal coliform standard in public water supplies was close to the national average during 2001. A comprehensive monitoring programme of the 56 public water supplies was in place in Donegal in 2001. A distinctive feature of the monitoring results for the public water supplies in Donegal was the poor rate of compliance with the aluminium standard. The compliance rate in 2001 was just 69%. One third (11 out of 33) of the supplies that monitor for aluminium did not comply with the standard at some stage of the year. All of the samples analysed for aluminium in Ballyshannon (12 samples analysed), Gortahork-Falcarragh (16 samples analysed) and Lettermacaward (11 samples analysed) exceeded the standard with some exceedances as high as six times the standard. Compliance with the aluminium standard was also problematic at Donegal/River Eske (9 out of 24 samples exceeded), Cranford (2 out of 5 samples exceeded), Falcarragh (8 out of 9 samples exceeded), Frosses-Iver (8 out of 10 samples exceeded), Killybegs (8 out of 24 samples exceeded) and Lough Mourne (13 out of 45 samples exceeded). The addition of alum at these treatment plants should be examined as a matter of priority and a programme of corrective action put in place immediately. The number and levels of aluminium exceedances at Ballyshannon, Gortahork-Falcarragh and Lettermacaward was unacceptable in 2001. Compliance with the faecal coliform standard is close to the national average and has improved slightly on the previous year. However, exceedances of the faecal coliform standard were still noted at 15 public water supplies. There were no nitrate or nitrite exceedances in public water supplies in Donegal in 2001.
In spite of an overall improvement in compliance with the faecal coliform standard over half (13) of the group water schemes monitored in 2001 were found to have faecal contamination.
Review of the Period 1999-2001
The overall bacterological quality of public water supplies was satisfactory during the review period. However, compliance in public water supplies with the aluminium standard was poor and deteriorated substantially in 2001, reversing the positive trend in 2000.
62 Quality of Drinking Water in Ireland A Report For The Year 2001
Compliance in 1999 was 78% which improved to 88% in 2000 and dropped to just 69% in 2001. Compliance with the fluoride standard remained consistently low at 89% during the review period. The quality of water supplied by group water schemes was poor during the review period.
63 Quality of Drinking Water in Ireland A Report For The Year 2001
3.11. DROGHEDA
Summary Information Number of Public Water Supplies Monitored during 2001: 2 Estimated Population Served by Public Water Supplies Monitored during 2001: 27,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 2 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There were two public water supplies monitored in Drogheda during 2001, collectively supplying water to a population of 27,000 people.
The bacteriological quality of both Staleen and Rosehall was excellent and both schemes were free of faecal coliforms in 2001. The good quality was further illustrated by full compliance with the ammonium, nitrate and nitrite standards. The only exceedances of note in Drogheda were the 4 exceedances (of 19 samples analysed) of the aluminium standard recorded in the Staleen supply.
Review of the Period 1999-2001
The quality of the drinking water was consistently good throughout the review period.
64 Quality of Drinking Water in Ireland A Report For The Year 2001
3.12. DUBLIN CITY
Summary Information Number of Public Water Supplies Monitored during 2001: See note* Estimated Population Served by Public Water Supplies Monitored during 2001: See note Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: All Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
Drinking water in Dublin comes from a mixture of surface water sources, primarily taken from the river Liffey catchment.
The bacteriological quality of the water supply in Dublin in 2001 was excellent with none of the 1,226 samples analysed found to contain faecal coliforms. The water supply was also fully compliant for nitrate and nitrite standards with only one exceedance (of 303 samples analysed) of the ammonium standard recorded. Extensive monitoring of the water supply in Dublin City (in all four sanitary authorities) for Cryptosporidium was also undertaken in 2001 with just 3 of the 343 samples indicating the presence of the parasite (all three samples detected Cryptosporidium at low levels). The sanitary authority is to be commended for this progressive monitoring programme. Overall the quality of drinking water in Dublin City was good.
Review of the Period 1999-2001
The quality of drinking water was good throughout the review period.
* The Greater Dublin Water Supply is supplied from raw water sources at Leixlip, Roundwood, Ballyboden and Ballymore Eustace and supplies approximately 1.3 million persons within the Dublin City, Fingal, Dun Laoghaire-Rathdown, South Dublin, Wicklow, Kildare and Meath sanitary authorities. 65 Quality of Drinking Water in Ireland A Report For The Year 2001
3.13. DUNDALK
Summary Information Number of Public Water Supplies Monitored during 2001: 1 Estimated Population Served by Public Water Supplies Monitored during 2001: 30,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 0 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 98.6% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There was one public water supply (Cavan Hill) monitored by Dundalk Town Council during 2001 which supplies water to a population of 30,000 people.
Compliance with the faecal coliform standard in Dundalk was above the national average during 2001. The overall quality of the Dundalk water supply in 2001 was satisfactory although there were two incidents of faecal coliforms detected in the supply. The second of these incidents necessitated the issuance of a ‘boil water’ notice for 7 days. However, quality of the supply was restored quickly and all samples analysed following the initial exceedance were clear. All other exceedances were minor in nature and were dealt with promptly by either flushing the mains (in the case of bacteriological exceedances) or by correcting problems with equipment (in the case of fluoride).
Review of the Period 1999-2001
Notwithstanding the faecal exceedances in 2001, the quality of the drinking water was satisfactory throughout the review period and there was an improvement in the compliance rate with fluoride which was problematic in 2000.
66 QualityQuality of Drinkingof Drinking Water Water in Irelandin Ireland A ReportA Report For The For YearThe Year2001 2001
3.14. DUN LAOGHAIRE-RATHDOWN
Summary Information Number of Public Water Supplies Monitored during 2001: See Dublin City Estimated Population Served by Public Water Supplies Monitored during 2001: See Dublin City Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: All Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
The majority of the water supply in Dun Laoghaire Rathdown is part of the greater Dublin supply. However, there are 3 small treatment works separate from this supply that are operated by Dun Laoghaire Rathdown County Council.
The bacteriological quality of drinking water in Dun Laoghaire Rathdown was excellent in 2001 with no incidents of faecal coliforms in the water supply. A small number of samples tested positive for total coliforms, however in all cases they were shown to be of non-faecal origin. The drinking water supplies in Dun Laoghaire Rathdown were also fully compliant for ammonium, nitrate, nitrite and turbidity. See also comments regarding Cryptosporidium monitoring in the section on Dublin City Council.
Review of the Period 1999-2001
The quality of drinking water in Dun Laoghaire Rathdown over the review period was good.
67 Quality of Drinking Water in Ireland A Report For The Year 2001
3.15. ENNIS
Summary Information Number of Public Water Supplies Monitored during 2001: 1 Estimated Population Served by Public Water Supplies Monitored during 2001: 20,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 1 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There was one public water supply monitored in Ennis in 2001 supplying a population of 20,000 people.
Compliance with the faecal coliform standard was above the national average in Ennis during 2001. As in 2000, a distinctive feature of the Ennis water supply was the total absence of detection of any type of coliform, either faecal or non-faecal. However, the number of exceedances of fluoride (12 of 63 samples analysed), iron (10 of 64 samples analysed), colour (9 of 64 samples analysed) and turbidity (4 of 64 samples analysed) increased, although the majority of these exceedances were only slightly in excess of the relevant standard.
Review of the Period 1999-2001
The bacteriological quality of the Ennis water supply has been excellent over the review period with a notable absence of any type of coliform exceedance detected. However, there has been a decrease in the compliance with the fluoride standard from 100% in 1999 to 95% in 2000 to just 81% in 2001 which needs to be addressed.
68 Quality of Drinking Water in Ireland A Report For The Year 2001
3.16. FINGAL
Summary Information Number of Public Water Supplies Monitored during 2001: See Dublin City Estimated Population Served by Public Water Supplies Monitored during 2001: See Dublin City Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 0 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
% Samples Free of Faecal Coliforms in Public Water Supplies: 99.8% % Samples Free of Faecal Coliforms in Group Water Schemes: N/As
Assessment of the Monitoring Results for 2001
There was one public water supply monitored in Fingal during 2001 (Leixlip) which is part of the Greater Dublin water supply.
Compliance with the faecal coliform standard in Leixlip was above the national average during 2001 and there was one incident of faecal coliforms detected in the Leixlip water supply. However, this exceedance was minor and the water returned to full compliance by the time the follow up sample had been analysed. As in 2000 there were some objectionable odour and taste problems noted in 2001 primarily related to the detection of chlorine in the water. Notwithstanding these organoleptic parameters, the quality of drinking water was good in Fingal in 2001. See also comments regarding Cryptosporidium monitoring in the section on Dublin City Council.
Review of the Period 1999-2001
The quality of drinking water during the review period was good.
69 QualityQuality of Drinkingof Drinking Water Water in Irelandin Ireland A ReportA Report For The For YearThe Year2001 2001
3.17. GALWAY CITY
Summary Information Number of Public Water Supplies Monitored during 2001: 2 Estimated Population Served by Public Water Supplies Monitored during 2001: 57,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 0 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 99.4% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There were 2 public water supplies monitored by Galway City Council during 2001 and these collectively supply water to approximately 57,000 people.
Compliance with the faecal coliform standard was above the national average during 2001. The quality of public water supplies in Galway City was generally satisfactory during 2001. However, the level of compliance with the total coliform standard was relatively low in 2001 (27 exceedances out of 319 samples analysed), although only 2 of these were faecal in origin (one at each of the treatment works).
Review of the Period 1999-2001
The quality of drinking water during the review period was satisfactory, however, there was a decline in compliance with the total coliform standard over the review period, which was needs to be addressed.
70 Quality of Drinking Water in Ireland A Report For The Year 2001
3.18. GALWAY (COUNTY)
Summary Information Number of Public Water Supplies Monitored during 2001: 47 Estimated Population Served by Public Water Supplies Monitored during 2001: 148,424 persons Number of Group Water Schemes Monitored during 2001: 517 Estimated Population Served by Group Water Schemes Monitored during 2001: 70,630 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 34 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 364
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 86.2% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 77.6%
Assessment of the Monitoring Results for 2001
There were 47 public and 517 group water schemes monitored by Galway County Council in 2001 and these collectively supply water to approximately 220,000 people.
Compliance with the faecal coliform standard for all public water supplies initially appears to be quite poor at 86%. However, a closer examination of the results reveal that the majority of exceedances relate to a single incident at Ballinasloe during August 2001 and the extensive monitoring that was carried out as a result of that incident. If all this additional monitoring is removed, the compliance rate for Galway County was 97% (i.e. close to the national average). Overall, there were 14 incidents of faecal contamination of the public water supplies in Galway County in 13 supplies. The affected supplies were Ballinasloe, Inishmore (2 incidents), Ballymoe, Clarinbridge/Kilcolgan, Cleggan/Claggaduff, Derryinver, Derryrush, Gort, Headford, Inishboffin, Kilconnel, Mid Galway and Newbridge. Compliance with the standard for colour was problematic with 53 samples (out of 283 samples analysed) in excess of the standard. Monitoring for aluminium was insufficient in 2001 with only 13 samples analysed from 3 supplies. Compliance with the aluminium standard was very poor in these supplies with 9 of the 13 samples exceeding the standard. Increased monitoring of aluminium at these supplies and others where alum is used as a coagulant should commence immediately. A positive feature of the public water supplies was the absence of any exceedances of the ammonium, nitrate and nitrite standards.
An extensive monitoring programme of 517 group water schemes was undertaken in Galway County in 2001. Of the 497 group water schemes monitored for coliforms 364 (73%) were found to be free of faecal contamination. The overall number of samples complying with the standard (77.6%) was above the national average and has improved over the previous year, although there is still a need for improvement. Although nitrates were generally not a problem in Galway as a whole, nitrate levels in excess of the standard were found at the Kilmoran/Gort group water scheme.
Review of the Period 1999-2001
Notwithstanding the Ballinasloe incident in 2001 the quality of drinking water in public water supplies improved over the review period and can be regarded as satisfactory. In spite of a substantial improvement in the total and faecal coliform standard over the review period the quality of drinking water in group water
71 Quality of Drinking Water in Ireland A Report For The Year 2001
schemes cannot be regarded as satisfactory in a significant number of schemes (133 of the 497 monitored for faecal coliforms).
72 Quality of Drinking Water in Ireland A Report For The Year 2001
3.19. KERRY
Summary Information Number of Public Water Supplies Monitored during 2001: 70 Estimated Population Served by Public Water Supplies Monitored during 2001: 124,847 persons Number of Group Water Schemes Monitored during 2001: 42 Estimated Population Served by Group Water Schemes Monitored during 2001: 7,864 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 43 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 26
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 92.3% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 64.0%
Assessment of the Monitoring Results for 2001
There were 70 public and 42 group water schemes monitored by Kerry County Council in 2001 and these collectively supply water to over 215,000 people.
Compliance with the faecal coliform standard in public water supplies was below the national average during 2001. As in 2000, the overall quality of drinking water in public water supplies is regarded as fair with 27 of the public water supplies in Kerry recording incidents of faecal contamination. The overall compliance rate of 92.3% is the lowest in the country. Gross incidents of faecal contamination (>20 cf/100 ml) were noted in Anascaul, Barraduff, Fahan, Glenbeigh, Glenfahan and Knockavroogeen. Excessive aluminium was also a feature of the Kerry monitoring results with 8 of the 18 supplies monitored exceeding the standard on at least one occasion. Gross exceedances (i.e. >1.0 mg/l Al) were recorded in Abbeydorney/Kilflyn, Inch, Lyre and Mid Kerry.
The quality of group water schemes, based on one sample per scheme, was also less than satisfactory with 36% of samples indicating the presence of faecal coliforms. Group water schemes recording gross exceedances of the faecal coliform standard include Allohert, Caher, Coom/Cordal, Cordal/Kilmurry (this scheme has since been abandoned), Inch/Foildown and Rineen. Excessive levels of nitrate were recorded in Clochaneleesh, Coolcorcoran and Glantanes. Clochnaleesh is of particular concern as a value of 147 mg/l was recorded.
Review of the Period 1999-2001
The quality of drinking water in public water supplies was fair throughout the review period. However, compliance with the faecal coliform and aluminium standard declined in 2001. The quality of drinking water in group water schemes was poor throughout the review period and declined for total and faecal coliforms.
73 Quality of Drinking Water in Ireland A Report For The Year 2001
3.20. KILDARE
Summary Information Number of Public Water Supplies Monitored during 2001: 24 Estimated Population Served by Public Water Supplies Monitored during 2001: 113,082 persons Number of Group Water Schemes Monitored during 2001: 8 Estimated Population Served by Group Water Schemes Monitored during 2001: 2,220 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 22 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 7
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 99.3% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 97.7%
Assessment of the Monitoring Results for 2001
There were 24 public and 8 group water schemes monitored by Kildare County Council during 2001 and these collectively supply water to over 115,000 people.
Compliance with the faecal coliform standard in public water supplies was above the national average in Kildare during 2001. The bacteriological quality of drinking water in public water supplies in Kildare was good. There were 16 exceedances (of 417 samples analysed) of the total coliform standard. All but 3 of these were non-faecal in origin and in the majority of instances relate to contamination at the sampling point. The three incidents of faecal contamination were all moderate exceedances (i.e. <20 cfu/100 ml). Of concern is the frequency of nitrate exceedances in the smaller public supplies in Kildare. In particular, exceedances of the nitrate standard were noted in Castlemitchell Housing supply (6 of 12 samples analysed), Kilbeg/Kildangan (2 of 2 samples analysed), Kilberry (1 of 12 samples analysed), Kilmeade/Moateview (8 of 10 samples analysed) and Kilmeade/St. Ita’s (1 of 10 samples analysed). The sanitary authority reported that the Kilbeg/Kildangan source was abandoned in 2001 due to excessive nitrate levels and that the remaining supplies with nitrate exceedances are to be replaced. The Agency welcomes such a development, as nitrate is a health related parameter and any exceedance of the standard is of concern.
The results of monitoring from group water schemes in Kildare indicate that the quality of drinking water in the majority of schemes is good. All but one of the group water schemes monitored were fully compliant with the faecal coliform standard. The only supply of concern is the Ballyroe/Leinster Lodge supply which recorded 4 exceedances (of 8 samples analysed) of the nitrate standard as well as a faecal exceedance.
Review of the Period 1999-2001
The quality of drinking water in both public and group water schemes in Kildare was good over the review period and improved significantly in 2001. However, the excessive levels of nitrate in several of the smaller public water supplies and one group water scheme is of concern and replacement of the sources of these supplies is urged as soon as possible.
74 Quality of Drinking Water in Ireland A Report For The Year 2001
3.21. KILKENNY
Summary Information Number of Public Water Supplies Monitored during 2001: 15 Estimated Population Served by Public Water Supplies Monitored during 2001: 51,409 persons Number of Group Water Schemes Monitored during 2001: 74 Estimated Population Served by Group Water Schemes Monitored during 2001: 4,304 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 10 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 63
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 95.4% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 87.5%
Assessment of the Monitoring Results for 2001
There were 15 public water supplies and 74 group water schemes monitored by Kilkenny County Council during 2001 serving a population of 55,000 people.
Compliance with the faecal coliform standard in public water supplies was below the national average in Kilkenny during 2001. There were 5 incidents of faecal contamination of public water supplies in 2001. These incidents were recorded in the Bennettsbridge, Castlecomer (Old), Kilkenny City (Troyswood), Mooncoin Regional and Clogh-Castlecomer supplies. All of the public water supplies were fully compliant for ammonium, nitrate and nitrite in 2001. Other parameters of concern were aluminium and fluoride. Exceedances of the aluminium standard were recorded in Kilkenny City (Troyswood) (2 of 9 samples analysed) and Mooncoin Regional (4 of 8 samples analysed). However, the compliance rate for both of these schemes has improved over the previous year and it is hoped that stringent efforts will be made to ensure that both of these schemes are brought into full compliance over the coming year. Fluoride exceedances were recorded in 10 of the 15 public supplies monitored in Kilkenny, although the number of exceedances has decreased since the previous year. An examination of the dosing regime at these plants should be carried out to ensure that exceedances of the standard are eliminated.
The quality of drinking water in group water schemes, based on a once a year sampling regime, is satisfactory in 63 of the 71 group water schemes monitored for faecal coliforms. However, the remainder of the group water schemes continue to have faecal contamination. Although the number of exceedances of the nitrate standard decreased in group water schemes in 2001, nitrate was still a problem in the Windgap group water scheme where a value of 58 mg/l was recorded in 2001.
Review of the Period 1999-2001
With the exception of the issues highlighted above the general quality of drinking water in public water supplies in Kilkenny was satisfactory with improvements noted in compliance with faecal coliform, ammonium, nitrate and aluminium standard over the review period. Compliance with the aluminium standard is, however, still relatively low and alum dosing at the plants specified above needs further refining. The quality of drinking water in the majority of group water schemes is satisfactory although the compliance rate for faecal coliforms has decreased slightly since 2000.
75 Quality of Drinking Water in Ireland A Report For The Year 2001
3.22. LAOIS
Summary Information Number of Public Water Supplies Monitored during 2001: 23 Estimated Population Served by Public Water Supplies Monitored during 2001: 49,716 persons Number of Group Water Schemes Monitored during 2001: 35 Estimated Population Served by Group Water Schemes Monitored during 2001: 6,086 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 22 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 29
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 99.8% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 95.0%
Assessment of the Monitoring Results for 2001
There were 23 public water supplies and 35 group water schemes monitored during 2001 collectively supplying water to a population of approximately 55,000 people.
Compliance with the faecal coliform standard in public water supplies was above the national average during 2001. The bacteriological quality of public water supplies in Laois was excellent in 2001. Of the 23 public water supplies monitored, 22 were free of faecal contamination while the sole supply that tested positive for the presence of faecal coliforms was Mountmellick. The offending sample contained only 1 faecal coliform (per 100 ml) and the quality was restored in the following sample. Furthermore, there were no exceedances of the ammonium or nitrate standards in any of the public water supplies in Laois. However, there was a notable lack of monitoring for aluminium and only one sample was analysed for iron and manganese. It has been reported that aluminium monitoring at Portarlington (the only supply that uses alum as a coagulant) commenced in February of 2002. Iron and manganese monitoring should commence immediately in light of the iron and manganese removal facilities used at the Portlaoise treatment works.
The quality of group water schemes was satisfactory in 2001 with 26 of the 32 schemes fully compliant with the faecal coliform standard. Faecal contamination was recorded in Aughmacart (1 out of 1 sample analysed), Ballacolla (4 out of 48 samples analysed), Derrynaserra/Mountsalam (2 out of 9 samples analysed), Heath (1 out of 14 samples analysed), Raheen (1 out of 9 samples analysed) and Reary (2 out of 3 samples analysed). Three group schemes were non-compliant with the nitrate standard (Attanagh, Barrowhouse and Dereen)
Review of the Period 1999-2001
The quality of drinking water in public water supplies over the review period was good and improved in terms of the bacteriological parameters. The quality of group water schemes was satisfactory over the review period and also improved in terms of faecal coliforms. However, the emergence in 2001 of group water schemes with nitrate values in excess of the standard is of concern.
76 Quality of Drinking Water in Ireland A Report For The Year 2001
3.23. LEITRIM
Summary Information Number of Public Water Supplies Monitored during 2001: 10 Estimated Population Served by Public Water Supplies Monitored during 2001: 16,140 persons Number of Group Water Schemes Monitored during 2001: 31 Estimated Population Served by Group Water Schemes Monitored during 2001: 8,352 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 6 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 6
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 97.9% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 32.5%
Assessment of the Monitoring Results for 2001
There were 10 public water supplies and 31 group water schemes monitored by Leitrim County Council during 2001 collectively supplying water to a population of approximately 24,000 people.
Compliance with the faecal coliform standard in public water supplies in Leitrim was close to the national average during 2001 and the overall bacteriological quality of drinking water in public water supplies was satisfactory. There were 5 incidents of faecal contamination of public water supplies at Carrigallen, Dowra, Erriff (2 incidents) and Manorhamilton. Public water supplies were fully compliant with the standards for ammonium, nitrate, nitrite and pH. The overriding feature of the monitoring results for public water supplies was the large number of exceedances of the aluminium standard (95 out of 217 samples analysed). All of these exceedances were confined to the Carrigallen (23 out of 23 samples exceeded), Dromahair (17 out of 23 samples exceeded), Drumkeeran (17 out of 23 samples exceeded) and South Leitrim Regional (38 out of 74 samples exceeded) supplies. The rate of compliance for aluminium is a significant deterioration on the previous year. Although many of these plants are old it is not acceptable that there be such a high number of exceedances. Indeed, 16 of these exceedances are considered gross (>1.0 mg/l). The sanitary authority is urged to review alum dosing practices at the four above mentioned treatment works to bring these supplies into compliance. Colour also is a problem at the Dowra plant with 16 samples (of 19 analysed) exceeding the standard.
The quality of drinking water in group water schemes in Leitrim is very poor with a mere 6 group schemes (of 31 monitored) complying with the faecal coliform standard. Of the 163 samples analysed for coliforms 125 (76.7%) tested positive for total coliforms with 110 (67.5%) of these indicating the presence of faecal contamination. Colour (88 of 164 samples exceeded), iron (71 of 164 samples exceeded), manganese (73 of 164 samples exceeded) and pH (50 of 164 samples exceeded) were also problematic in group water schemes. A considerable amount of work is necessary to bring these poor quality schemes up to standard.
Review of the Period 1999-2001
The bacteriological quality of public water supplies in Leitrim has remained consistently good throughout the review period. However, compliance with the aluminium standard has deteriorated substantially from 69% compliance in 1999 to 56% compliance in 2001. The quality of drinking water in group water
77 Quality of Drinking Water in Ireland A Report For The Year 2001
schemes has deteriorated considerably from 92% compliance with the faecal coliform standard in 1999 to just 33% in 2001. This is most likely due to the increase in monitoring that has occurred over the period and hence a more accurate assessment of the situation is presented.
78 Quality of Drinking Water in Ireland A Report For The Year 2001
3.24. LIMERICK (COUNTY)
Summary Information Number of Public Water Supplies Monitored during 2001: 42 Estimated Population Served by Public Water Supplies Monitored during 2001: 69,677 persons Number of Group Water Schemes Monitored during 2001: 79 Estimated Population Served by Group Water Schemes Monitored during 2001: 8,632 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 42 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 64
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 88.2%
Assessment of the Monitoring Results for 2001
There were 42 public water supplies and 79 group water schemes monitored by Limerick County Council during 2001 collectively supplying water to a population of approximately 78,000 people.
Compliance with the faecal coliform standard in public water supplies was above the national average in Limerick County during 2001. Indeed, the most notable feature of the monitoring results for public water supplies in Limerick County is the complete absence of faecal coliforms from all of the 707 samples analysed. The public water supplies were also fully compliant for ammonium, nitrate, odour, taste and pH. There were some problems with compliance with the aluminium standard at Adare where 14 (of 29 samples analysed) were marginally in excess of the standard. There was a significant number of samples marginally in excess of the fluoride standard at Abbeyfeale (8 of 37 samples analysed), Adare (13 of 29 samples analysed) and Kilmallock (12 of 25 samples analysed). Both the aluminium and fluoride exceedances (though marginal) should be examined and doses of the relevant chemical adjusted accordingly. As in previous years manganese continues to feature in the list of exceedances for Limerick. Though not normally harmful to humans excessive levels of manganese may cause water to become coloured and hence objectionable to consumers.
Of the 79 group water schemes monitored in 2001, 64 were free of faecal coliforms. Thus, many of the schemes may be regarded as of satisfactory quality. However, 17 of the 144 samples analysed in Limerick tested positive for the presence of faecal coliforms, thus problems continue to arise in a number of schemes.
Review of the Period 1999-2001
The quality of drinking water in public water supplies was satisfactory over the review period. In spite of a slight reduction in compliance with the aluminium standard, compliance with the coliforms standard, both total and faecal, improved over the review period. Although the quality of the majority of group water schemes can be regarded as satisfactory there are still a significant number of schemes that are non- compliant. However, there was a welcome improvement in the compliance rate with total and faecal coliforms over the review period
79 Quality of Drinking Water in Ireland A Report For The Year 2001
3.25. LIMERICK CITY
Summary Information Number of Public Water Supplies Monitored during 2001: 1 Estimated Population Served by Public Water Supplies Monitored during 2001: 55,242 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 0 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 99.3% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There was one drinking water supply in Limerick City in 2001 supplying water to a population of 55,000 people.
Compliance with the faecal coliform standard was above the national average in Limerick City during 2001. The overall quality of drinking water in Limerick City was good. There were two exceedances of the total coliforms standard, just one of which was subsequently found to be of faecal origin. There was an increasing number of aluminium exceedances. However, the majority of these exceedances were moderate (i.e. <0.4 mg/l).
Review of the Period 1999-2001
The quality of drinking water during the review period was good.
80 Quality of Drinking Water in Ireland A Report For The Year 2001
3.26. LONGFORD
Summary Information Number of Public Water Supplies Monitored during 2001: 9 Estimated Population Served by Public Water Supplies Monitored during 2001: 40,840 persons Number of Group Water Schemes Monitored during 2001: 48 Estimated Population Served by Group Water Schemes Monitored during 2001: 1,608 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 8 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 27
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 96.4% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 66.2%
Assessment of the Monitoring Results for 2001
There were 9 public water supplies and 48 group water schemes monitored by Longford County Council during 2001 collectively supplying water to a population of approximately 42,000 people.
Compliance with the faecal coliform standard in public water supplies was slightly below the national average in Longford during 2001, although the quality of drinking water in public water supplies in general was satisfactory. Public water supplies in Longford were in general free of faecal contamination with the sole exception of the Ardagh supply where there were 4 exceedances of the faecal coliform standard (of 12 samples analysed). The only other notable exceedance was aluminium in the Longford Central supply where 17 samples (of 31 analysed) exceeded the standard. This is almost identical to the number of exceedances in the previous year and the sanitary authority is urged to investigate the matter and amend alum dosing accordingly.
The quality of group water schemes was poor in Longford in 2001. A large proportion (51 of 74 samples analysed) tested positive for the presence of coliforms. Of these, 25 indicated the presence of faecal coliforms.
Review of the Period 1999-2001
Notwithstanding the aluminium exceedances at the Longford Central supply the quality of drinking water in public water supplies was satisfactory throughout the review period. Monitoring data for group water schemes was not submitted in 2000 and the quality was poor in 2001.
81 Quality of Drinking Water in Ireland A Report For The Year 2001
3.27. LOUTH
Summary Information Number of Public Water Supplies Monitored during 2001: 13 Estimated Population Served by Public Water Supplies Monitored during 2001: 27,316 persons Number of Group Water Schemes Monitored during 2001: 11 Estimated Population Served by Group Water Schemes Monitored during 2001: 5,544 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 10 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 5
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 94.6% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 81.2%
Assessment of the Monitoring Results for 2001
There were 13 public water supplies and 11 group water schemes monitored by Louth County Council during 2001 collectively supplying water to over 32,000 persons.
Compliance with the faecal coliform standard in public water supplies was below the national average in Louth during 2001. Notwithstanding this, the quality of drinking water in public water supplies was satisfactory in 2001. There were 3 incidents of faecal contamination of the public water supplies recorded in 2001. These incidents occurred in Ardee, Dunleer and Sheelagh/Courtbane. All these incidents were relatively short-lived and the supplies were fully compliant for the remainder of the year. The addition of aluminium at Ardee (6 of 9 samples exceeded the standard) was problematic. The public water supplies in Louth were in full compliance with the ammonium, nitrate, nitrite, iron and pH standards.
A notable feature of group water schemes in Louth was the nitrate exceedances recorded at Sheepgrange (11 of 11 samples analysed exceeded the standard) and Tullyallen (1 of 13 samples analysed exceeded the standard). The sanitary authority has prepared an Action Programme to deal with the nitrate problem in Sheepgrange. The monitoring programme for group water schemes is also noteworthy with an average of 6 samples analysed per supply.
Review of the Period 1999-2001
The general quality of public water supplies was satisfactory during the review period, although there has been a decline in compliance with the aluminium standard in 2001. The quality of group water schemes, although less than satisfactory has improved over the review period
82 Quality of Drinking Water in Ireland A Report For The Year 2001
3.28. MAYO
Summary Information Number of Public Water Supplies Monitored during 2001: 23 Estimated Population Served by Public Water Supplies Monitored during 2001: 68,573 persons Number of Group Water Schemes Monitored during 2001: 132 Estimated Population Served by Group Water Schemes Monitored during 2001: 43,524 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 18 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 59
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 98.3% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 55.6%
Assessment of the Monitoring Results for 2001
There were 23 public water supplies and 132 group water schemes monitored by Mayo County Council during 2001 collectively supplying water to an estimated population of over 110,000 persons.
Compliance with the faecal coliform standard in public water supplies was above the national average in Mayo during 2001. The quality of drinking water in public water supplies overall was satisfactory. Approximately 5% of samples analysed for coliforms were found to exceed the standard. However, just 8 (1.7%) of these were found to be of faecal origin. The notable feature of the public water supplies in Mayo was the occurrence of breaches of the national fluoride standard (11 of 70 samples analysed) though all were below the EU Standard of 1.5 mg/l. No aluminium monitoring was carried out in 2001 in spite of the fact that alum is used as a coagulant in Achill, Ballina Wherrew, Belmullet, Kiltimagh, Shrule, Swinford and Wesport. The sanitary authority is urged to commence monitoring of aluminium at these supplies immediately.
The overriding feature of the group water schemes is the poor rate of compliance with the faecal coliform standard. Based on a limited sampling regime of one sample per year for most of the group water schemes 70 supplies were found to be contaminated with faecal material. High levels of colour (46 of 214 samples exceeded), iron (35 of 214 samples exceeded) and manganese (26 of 214 samples exceeded) were also a problem in group water schemes. Overall, the quality of group water schemes in Mayo was poor in 2001.
Review of the Period 1999-2001
The general quality of drinking water in public water supplies was satisfactory, although no monitoring of aluminium was undertaken during the review period. The quality of group water schemes was consistently poor and the incidence of faecal contamination of these schemes was high throughout the review period.
83 Quality of Drinking Water in Ireland A Report For The Year 2001
3.29. MEATH
Summary Information Number of Public Water Supplies Monitored during 2001: 25 Estimated Population Served by Public Water Supplies Monitored during 2001: 73,651 persons Number of Group Water Schemes Monitored during 2001: 8 Estimated Population Served by Group Water Schemes Monitored during 2001: 2,379 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 18 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 8
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 95.8% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 100%
Assessment of the Monitoring Results for 2001
There were 25 public water supplies and 8 group water schemes monitored by Meath County Council during 2001 collectively supplying water to a population of approximately 75,000 people. Parts of Meath are also served by the Greater Dublin water supply.
Compliance with the faecal coliform standard in public water supplies in Meath was below the national average during 2001. Public water supplies in Meath were of satisfactory quality in 2001 although incidences of faecal coliforms were detected in public water supplies in Ashbourne, Athboy (2 incidents), Ballivor (2 incidents), Castletown, Drumconrath (2 incidents), East Meath and Slane. The majority of these incidents were moderate exceedances of the standard. Seventeen fluoride exceedances were recorded (of 154 samples analysed). Seven of these exceedances relate to the Drunconrath supply. There was also one exceedance of the nitrate standard (of 1 sample analysed) at Moynalty.
The monitoring results for group water schemes were (except for the Kiltale supply) based on a one or two sample per scheme regime. Based on this limited monitoring regime, the bacteriological quality of these supplies was apparently good without a single exceedance of the faecal coliform standard in the 15 samples analysed in 2001.
Review of the Period 1999-2001
The general quality of drinking water in public water supplies was satisfactory throughout the review period, though there was a slight decline in compliance with the coliforms standard (both faecal and total). An improvement was noted in compliance with the aluminium standard. Based on the limited monitoring programme there was an apparent improvement in the quality of drinking water in group water schemes and full compliance was achieved with the faecal coliform standard in 2001.
84 Quality of Drinking Water in Ireland A Report For The Year 2001
3.30. MONAGHAN
Summary Information Number of Public Water Supplies Monitored during 2001: 15 Estimated Population Served by Public Water Supplies Monitored during 2001: 22,045 persons Number of Group Water Schemes Monitored during 2001: 13 Estimated Population Served by Group Water Schemes Monitored during 2001: 19,674 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 13 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 5
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 98.5% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 87.4%
Assessment of the Monitoring Results for 2001
There were 15 public water supplies and 13 group water schemes monitored by Monaghan County Council which collectively supplied water to a population of approximately 40,000 people.
Compliance with the faecal coliform standard in public water supplies was above the national average in Monaghan during 2001. The quality of drinking water in public water supplies was satisfactory in Monaghan with just two moderate exceedances of faecal coliforms in 2001 (Emyvale and Glaslough). There were no exceedances of the ammonium, nitrate, nitrite and pH standards. The salient feature of the Monaghan results is the exceedances of the iron and manganese standard at the Monaghan Town supply. A total of 8 samples were analysed for iron and manganese, 4 of which failed the iron standard and 5 of which failed the manganese standard. A new treatment plant for Monaghan Town was opened in July 2002 incorporating iron and manganese removal and it is anticipated that this should alleviate the current problems in complying with these standards.
A notable feature of the group water schemes was the relatively large number of samples analysed. A total of 111 samples were analysed in the 13 schemes for coliforms. Based on the results submitted only five of the schemes monitored were free of faecal contamination. Colour and manganese were a problem in a number of supplies with 23 colour exceedances (of 45 samples analysed) and 19 manganese exceedances (of 44 samples analysed) reported.
Review of the Period 1999-2001
The general quality of drinking water in public water supplies was satisfactory and improved over the review period. In contrast the quality of group water schemes was fair, although compliance has improved slightly for faecal coliforms over the review period.
85 Quality of Drinking Water in Ireland A Report For The Year 2001
3.31. NORTH TIPPERARY
Summary Information Number of Public Water Supplies Monitored during 2001: 27 Estimated Population Served by Public Water Supplies Monitored during 2001: 42,620 persons Number of Group Water Schemes Monitored during 2001: 54 Estimated Population Served by Group Water Schemes Monitored during 2001: 8,220 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 19 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 26
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 95.6% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 74.1%
Assessment of the Monitoring Results for 2001
There were 27 public water supplies and 54 group water schemes monitored by North Tipperary County Council during 2001 collectively supplying water to an estimated population of over 50,000 persons.
Compliance with the faecal coliform standard in public water supplies was below the national average in North Tipperary during 2001. The overall quality of drinking water in public water supplies was satisfactory in North Tipperary although there were a number of incidents of faecal contamination of the public water supplies. Whilst 19 of the 27 public water supplies were free of faecal coliforms, there were incidences of faecal coliforms in Borrisokane (2 incidents), Carrig/Riverstown/Rathcabbin, Clonakenny, Cloghjordan, Lorrha, Nenagh, Silvermines and Thurles. Only the Clonakenny incident was considered serious (i.e. >20 cfu/100 ml). All public water supplies in North Tipperary were fully compliant with the standards for aluminium, ammonium, nitrate and pH.
Coliforms dominate the list of exceedances for group water schemes with just 13 schemes free of coliforms in 2001. Of the 41 group water schemes that tested positive for the presence of coliforms 28 of these were of faecal origin. Serious exceedances of the faecal coliform standard (i.e. >20 cfu/100 ml) were recorded in Ballycasey, Bawn/Kilgriffith/Kilmore, Castlecranna, Castleleiney A, Castlelough, Cloneybrien, Graigue/Pouldine, Gurteenkilla, Kilbillier and Killien. A feature of some group water schemes in North Tipperary was the high levels of nitrates found in Ballycasey (2 of 6 samples exceeded), Cunahurt/Knockalten (5 of 10 samples analysed), Garrynamone/Cormacstown (1 of 4 samples analysed) and Rathnaleen (1 of 2 samples analysed).
Review of the Period 1999-2001
The overall quality of drinking water from public water supplies was satisfactory over the review period. Notably, there was a halving in the number of fluoride exceedances in 2001 as compared to the previous two years. By contrast, the quality of drinking water in group water schemes was unsatisfactory although this has improved somewhat over the review period.
86 Quality of Drinking Water in Ireland A Report For The Year 2001
3.32. OFFALY
Summary Information Number of Public Water Supplies Monitored during 2001: 22 Estimated Population Served by Public Water Supplies Monitored during 2001: 39,485 persons Number of Group Water Schemes Monitored during 2001: 20 Estimated Population Served by Group Water Schemes Monitored during 2001: 11,086 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 17 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 13
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 98.2% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 90.1%
Assessment of the Monitoring Results for 2001
There were 22 public water supplies and 20 group water schemes monitored by Offaly County Council during 2001 collectively supplying water to a population of approximately 50,000 persons.
Compliance with the faecal coliform standard in public water supplies was above the national average in Offaly during 2001. The overall quality of drinking water in public water supplies in Offaly was satisfactory and although coliforms were detected in 31 samples (of 327 samples analysed) just 6 of these were of faecal origin. Public water supplies that recorded exceedances of the faecal coliform standard were Clara (1 of 13 samples analysed), Coolderry (1 of 16 samples analysed), Dunkerrin (1 of 37 samples analysed), Kilcormac (1 of 13 samples analysed) and Rhode (2 of 16 samples analysed). Public water supplies in Offaly were fully compliant for the ammonium, colour, nitrate, nitrite, pH and turbidity standards. The other feature of note with regard to the quality was the relatively high number of occurrences of odour (34 of 138 samples), which for the most part related to chlorine odours.
A comprehensive monitoring programme ensured that all group water schemes were monitored at least 4 times in 2001. The results indicate that in 7 of the 20 schemes monitored faecal coliforms were present at least once during the year. The overall quality was fair although the presence of coliforms of faecal origin in 7 schemes is of concern. Excessive levels of nitrates were recorded in the Corndarragh group water scheme (2 samples of 7 analysed), which is of concern.
Review of the Period 1999-2001
The quality of drinking water was satisfactory in public water supplies throughout the review period, whilst the quality of drinking water in group water schemes was fair.
87 Quality of Drinking Water in Ireland A Report For The Year 2001
3.33. ROSCOMMON
Summary Information Number of Public Water Supplies Monitored during 2001: 17 Estimated Population Served by Public Water Supplies Monitored during 2001: 43,197 persons Number of Group Water Schemes Monitored during 2001: 182 Estimated Population Served by Group Water Schemes Monitored during 2001: 18,082 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 6 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 131
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 94.7% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 66.6%
Assessment of the Monitoring Results for 2001
There were 17 public water supplies and 182 group water schemes monitored by Roscommon County Council during 2001 collectively supplying water to a population of over 60,000.
Compliance with the faecal coliform standard in public water supplies was below the national average in Roscommon during 2001. A total of 13 of the 17 supplies tested positive for the presence of coliforms during 2001, 11 of which were found to be of faecal origin. Incidents of faecal contamination were recorded in Arigna, Ballyfarnan, Ballyleague, Ballinlough/Loughglynn (2 incidents), Boyle/Ardcane, Castlerea Regional, Grangemore (5 incidents), Keadue, Knocknacroghery/Leacarrow, North East Regional Water Supply Scheme (3 incidents) and South Roscommon Regional (2 incidents). However, all of the public water supplies in Roscommon were free of exceedances of the ammonium, nitrate, nitrite and pH standards. An additional feature of the public water supplies in Roscommon was frequent exceedances of the colour standard at Grangemore (16 of 17 samples exceeded) and Arigna (10 of 20 samples exceeded).
There was a comprehensive monitoring programme in place for the group water schemes in Roscommon that resulted in over 1000 samples being analysed in 182 schemes. The quality of drinking water in group water schemes was poor in 2001 with 34% of samples testing positive for faecal coliforms. However, faecal coliforms were not detected in 131 of the group schemes monitored in 2001 in Roscommon.
Review of the Period 1999-2001
The overall quality of drinking water in public water supplies was satisfactory throughout the review period. The extensive monitoring of group water schemes in both 2000 and 2001 is to be welcomed, however, the quality of many of these schemes was poor.
88 Quality of Drinking Water in Ireland A Report For The Year 2001
3.34. SLIGO TOWN
Summary Information Number of Public Water Supplies Monitored during 2001: 3 Estimated Population Served by Public Water Supplies Monitored during 2001: Incl. in Sligo Co. Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 3 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
There were three public water supplies monitored by Sligo Borough Council during 2001 (Lough Gill (Cairns Hill and Foxes Den) and Kinsellagh).
Compliance with the faecal coliform standard in Sligo Town was above the national average during 2001. The bacteriological quality of drinking water in Sligo Town was excellent in 2001 and it is noteworthy that none of the 523 samples analysed were found to contain faecal coliforms. Thus the overall quality of drinking water was good in 2001. However, there was a significant number of exceedances of the colour (5 of 16 samples analysed) and iron (7 of 16 samples analysed) standard.
Review of the Period 1999-2001
The general quality of drinking water in Sligo Town was good and has improved substantially over the review period. The compliance rate with the faecal coliforms standard improved from 73% in 1999 to 100% in 2001.
89 Quality of Drinking Water in Ireland A Report For The Year 2001
3.35. SLIGO COUNTY
Summary Information Number of Public Water Supplies Monitored during 2001: 8 Estimated Population Served by Public Water Supplies Monitored during 2001: 31,375 persons* Number of Group Water Schemes Monitored during 2001: 5 Estimated Population Served by Group Water Schemes Monitored during 2001: 3,404 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 6 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 0
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 96.7% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 0% *includes Sligo Town
Assessment of the Monitoring Results for 2001
There were 8 public water supplies and 5 group water schemes monitored by Sligo County Council during 2001 collectively supplying water to an estimated population of 35,000 people.
Compliance with the faecal coliform standard in public water supplies was close to the national average in Sligo in 2001. In general the bacteriological quality of public water supplies was good. However, there were two incidents of faecal contamination of the public water supplies in 2001. A gross incident of faecal contamination was recorded in the Calry supply in August of 2001 (faecal coliforms levels too numerous to count were detected) while there was also a minor incident at the Lough Talt supply (one sample detected 1 cfu/100 ml). Colour (10 of 31 samples analysed) and iron (11 of 30 samples analysed) exceedances were recorded at the Lough Gill supply while odour (chlorine) was problematic at the North Sligo supply (12 of 18 samples exceeded).
Limited monitoring of group water schemes was undertaken in Sligo County in 2001 with just 5 samples analysed. All 5 samples analysed indicated the presence of faecal contamination, although it is difficult to make an overall assessment of the quality of group water schemes in Sligo based on the limited number of samples.
Review of the Period 1999-2001
The overall quality of drinking water in public water supplies was satisfactory during the review period and there was a slight improvement in the compliance rate for coliforms (both total and faecal) over the review period. Although limited monitoring results were submitted for group water schemes in 2001, making comparison difficult, the drinking water quality of samples taken over the review period was poor.
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3.36. SOUTH DUBLIN
Summary Information Number of Public Water Supplies Monitored during 2001: See Dublin City Estimated Population Served by Public Water Supplies Monitored during 2001: See Dublin City Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: All Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
The drinking water for South Dublin is mostly part of the Greater Dublin water supply. There is also one small supply at Brittas.
The bacteriological quality of drinking water in South Dublin was excellent and is notable for its absence of any exceedance of the faecal coliform standard and high compliance rate with the total coliforms standard. See also comments regarding Cryptosporidium monitoring in the section on Dublin City Council.
Review of the Period 1999-2001
The general quality of drinking water in South Dublin was consistently good throughout the review period and was of excellent bacteriological quality.
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3.37. SOUTH TIPPERARY
Summary Information Number of Public Water Supplies Monitored during 2001: 24 Estimated Population Served by Public Water Supplies Monitored during 2001: 53,888 persons Number of Group Water Schemes Monitored during 2001: 11 Estimated Population Served by Group Water Schemes Monitored during 2001: 560 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 19 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 4
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 97.4% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 56.3%
Assessment of the Monitoring Results for 2001
There were 24 public water supplies and 11 group water schemes monitored by South Tipperary County Council during 2001 collectively supplying water to a population of approximately 54,000.
Compliance with the faecal coliform standard in public water supplies was slightly above the national average in South Tipperary during 2001. The overall quality of drinking water in public water supplies was satisfactory in 2001. There were 5 incidents of faecal coliforms present in public water supplies at Burncourt, Cahir Reservoir, Gortnapisha, Mullenbawn and Tipperary. The most distinctive feature of the monitoring results was the large number of aluminium exceedances at all of the treatment plants that use aluminium as a coagulant. There were a large number of exceedances at Dundrum Regional (4 of 18 samples analysed), Carrick-on-Suir/River Lingaun (4 of 17 samples analysed), Galtee Regional (9 of 39 samples analysed), Ardfinnan (18 of 27 samples analysed) and Killurney (16 of 29 samples analysed). The difficulties in complying with the aluminium standard in South Tipperary primarily relate to the nature of the water that is being treated in particular the rapid variations in the quality of the upland raw waters from where these supplies are sourced. There was one anomalous nitrate result in the Carrick-on-Suir/River Lingaun supply which was not repeated in the supply.
Almost two-thirds of the group water schemes monitored were found to be contaminated by faecal coliforms and thus were of poor quality.
Review of the Period 1999-2001
The general quality of drinking water in public water supplies was satisfactory. However, there was a significant decline in the rate of compliance with the aluminium standard throughout the review period. By comparison the quality of group water schemes was poor.
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3.38. WATERFORD CITY
Summary Information Number of Public Water Supplies Monitored during 2001: 1 Estimated Population Served by Public Water Supplies Monitored during 2001: 50,000 persons Number of Group Water Schemes Monitored during 2001: N/A Estimated Population Served by Group Water Schemes Monitored during 2001: N/A
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 1 Number of Group Water Schemes Monitored Free of Faecal Coliforms: N/A
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: N/A
Assessment of the Monitoring Results for 2001
The drinking water supply in Waterford City serving a population of 50,000 was fully compliant with the Drinking Water Regulations in 2001 and was thus of excellent quality.
Review of the Period 1999-2001
The general quality of drinking water was good throughout the review period.
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3.39. WATERFORD COUNTY
Summary Information Number of Public Water Supplies Monitored during 2001: 111 Estimated Population Served by Public Water Supplies Monitored during 2001: 42,600 persons Number of Group Water Schemes Monitored during 2001: 10 Estimated Population Served by Group Water Schemes Monitored during 2001: Insufficient data
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 94 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 10
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 92.6% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 100%
Assessment of the Monitoring Results for 2001
There were 111 public water supplies and 10 group water schemes monitored by Waterford County Council during 2001 collectively supplying water to a population of over 42,000 people. The public water supplies are for the most part small in size.
While the quality of drinking water in public water supplies in Waterford was satisfactory in the majority of supplies, compliance with the faecal coliform standard in these supplies was below the national average during 2001. Incidents of faecal contamination were recorded in Ballyduff-Ballylemon, Ballymacarbry (2 incidents), Carrowgarriff, Clonea Power (2 incidents), Colligan, Crehanagh (2 incidents), Dungarvan UDC, Joanstown (2 incidents), Kereen, Kilgobnet, Kilnafrehan, Liskealty, Poulavanoge, Ring/Helvick/Seaview, Shanacoole and Shean. High levels of iron were also recorded in the Stradbally supply (11 of 16 samples analysed), while a number of supplies had low pH problems. Aluminium compliance at Ballinacourty/Deelish was unsatisfactory with 12 exceedances (of 46 samples analysed) of the standard.
Based on the limited monitoring conducted (one sample per scheme) the quality of drinking water supplied by group water schemes was good with no exceedances of the faecal coliform standard recorded.
Review of the Period 1999-2001
The general quality of drinking water in public water supplies was satisfactory in most supplies throughout the review period. Based on the limited monitoring conducted during the review period, the quality of drinking water in group schemes was good.
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3.40. WESTMEATH
Summary Information Number of Public Water Supplies Monitored during 2001: 13 Estimated Population Served by Public Water Supplies Monitored during 2001: 52,500 persons Number of Group Water Schemes Monitored during 2001: 2 Estimated Population Served by Group Water Schemes Monitored during 2001: 500 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 7 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 2
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 95.5% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 100%
Assessment of the Monitoring Results for 2001
There were 13 public water supplies and 2 group water schemes monitored by Westmeath County Council during 2001 collectively supplying water to a population of 53,000 people.
Compliance with the faecal coliform standard in public water supplies was below the national average in Westmeath during 2001, although the overall quality of drinking water in public water supplies was satisfactory. Of concern, however were faecal exceedances recorded in the Ballymore, Castlepollard High and Low Level, Mullingar High and Low Level and Mullingar Town Independent supplies. There were also a number of exceedances of the aluminium standard (4 of 28 samples analysed) in the Athlone supply. The public water supplies were fully compliant for the ammonium, nitrate, nitrite, pH and turbidity standards.
There were two group water schemes monitored in Westmeath during 2001. Both were monitored extensively and of the 15 and 13 samples analysed for the Mount Temple scheme and Multyfarnham respectively, all were found to be free of faecal coliforms. The monitoring results for total coliforms for the Mount Temple scheme (14 of 15 samples exceeded the standard) most likely indicate that there is a problem with the distribution mains.
Review of the Period 1999-2001
The quality of drinking water in public water supplies was satisfactory throughout the review period and there was a slight improvement in compliance with the aluminium standard. Notwithstanding the problems of non-compliance with the total coliform standard in the Mount Temple supply, the quality of the two group water schemes was generally satisfactory throughout the review period.
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3.41. WEXFORD
Summary Information Number of Public Water Supplies Monitored during 2001: 33 Estimated Population Served by Public Water Supplies Monitored during 2001: 90,147 persons Number of Group Water Schemes Monitored during 2001: 7 Estimated Population Served by Group Water Schemes Monitored during 2001: 3,686 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 33 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 5
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 100% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 90.9%
Assessment of the Monitoring Results for 2001
There were 33 public water supplies and 7 group water schemes monitored by Wexford County Council during 2001 collectively supplying water to an estimated 94,000 persons.
Compliance with the faecal coliforms standard in public water supplies was above the national average in Wexford during 2001. The bacteriological quality of drinking water in public water supplies was good in 2001. In general compliance with the drinking water standards was good. In particular it was notable that there was not a single exceedance of the faecal coliform standard in 2001. The only issue of concern was a high level of nitrate in the Ballywilliam/Fatima Place supply, though it was reported that an alternative source is being sought for this supply at present.
The quality of group water schemes was satisfactory in the majority of schemes. Two schemes, Ballymoney/Tara Hill and Killinieren, recorded exceedances of the faecal coliform standard.
Review of the Period 1999-2001
The general quality of public water supplies and most group water schemes was satisfactory throughout the review period.
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3.42. WICKLOW
Summary Information Number of Public Water Supplies Monitored during 2001: 43 Estimated Population Served by Public Water Supplies Monitored during 2001: 87,985 persons Number of Group Water Schemes Monitored during 2001: 14 Estimated Population Served by Group Water Schemes Monitored during 2001: 804 persons
Results of Microbiological Analysis: Number of Public Water Supplies Monitored Free of Faecal Coliforms: 34 Number of Group Water Schemes Monitored Free of Faecal Coliforms: 12
Percentage of Samples Free of Faecal Coliforms in Public Water Supplies: 97.4% Percentage of Samples Free of Faecal Coliforms in Group Water Schemes: 90.5%
Assessment of the Monitoring Results for 2001
There were 43 public water supplies and 14 group water schemes monitored by Wicklow County Council during 2001, though some of the public supplies are part of the distribution network of the Greater Dublin water supply. The results of monitoring that were previously discussed separately in previous years reports for Bray are now included in the Wicklow report.
Compliance with the faecal coliform standard in public water supplies is close to the national average in Wicklow during 2001. Overall, the bacteriological quality of drinking water was satisfactory in Wicklow during 2001. However, faecal coliforms were detected in the Aughrim/Annacurra, Ballyknockan, Coolboy/Coolfancy, Enniskerry, Kiltegan, Knockanarrigan, Rathdangan, Bray and Kilcoole supplies, albeit at relatively low levels. Of concern is the poor rate of compliance with the aluminium standard. On a county wide basis just 55% of samples analysed for aluminium complied with the standard. The poor rate of compliance with the aluminium standard was particularly noticeable at Arklow (12 of 24 samples exceeded), Enniskerry (10 of 10 samples exceeded), Laragh/Anamoe (9 of 14 samples exceeded) and Wicklow Regional (8 of 25 samples exceeded). These poor rates of compliance, particularly that of Enniskerry, should be examined by the sanitary authority as a matter of urgency. More specifically, the dosing of alum at these treatment plants should be reviewed. A high level of nitrates was also detected in the Ballyconnell water supply during 2001.
Based on the limited monitoring conducted, the quality of drinking water supplied by group water schemes was satisfactory in the majority of cases. Exceedances of the faecal coliform standard were recorded in two schemes while an exceedance of the nitrate standard was recorded in one scheme at Ballynavortha.
Review of the Period 1999-2001
While the bacteriological quality of public water supplies was satisfactory during the review period the compliance with the aluminium standard was poor. For the second year in succession every sample analysed for aluminium in the Enniskerry water supply exceeded the standard. Poor compliance has been recorded in a number of supplies in Wicklow over the review period. This situation is unacceptable and corrective action should be taken by Wicklow County Council as a matter of urgency. Based on the limited monitoring, the quality of drinking water in group water schemes has improved over the review period and is satisfactory in the majority of cases.
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4. EPA AUDITS
4.1. INTRODUCTION
For over a century sanitary authorities have been required by law to protect public health by providing pure and wholesome water supplies. Water is abstracted from suitable sources by the sanitary authorities and subjected to the treatment processes needed to make it fit for distribution and, ultimately, human consumption. Its quality is monitored within the treatment works, along the distribution system and at the point of eventual use - the consumer's tap. This vital monitoring function is discharged by the sanitary authorities themselves and by health board officials who act both in their own right - under public health legislation - and, often, on an agency basis for the sanitary authorities.
These arrangements apply in the case of all public water supplies from the small village borehole to the large regional water supply scheme. Private water supplies, including group schemes, have also now come within the supervisory function of the sanitary authorities who are formally responsible for monitoring all drinking water supplies under the European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988.
The first report on drinking water quality in Ireland examined some 7,500 samples taken during 1989, and reported by sanitary authorities. Since then there has been a steady increase in the numbers of samples taken each year and in 2001 the numbers of samples reported reached 22,453. Though the significant increase in reporting by sanitary authorities over the years is to be welcomed it is noted that a number of drinking water supplies consistently breach the drinking water standards. The responsibilities placed on sanitary authorities are quite specific and in general require corrective actions to be taken as soon as is practicable, including warning users where there is an unacceptable risk to public health.
In 2001, the EPA undertook a series of random audits on sanitary authorities, in particular focusing on the management of reported exceedances of the drinking water standards. These audits were extended to other sanitary authorities in 2002. The Agency intends to carry out further audits in future years and include the findings in the annual drinking water reports. This section of the report provides the background and the results of the recent series of EPA audits.
4.2. AUDITS
The EPA undertook a number of audits to determine the conformity of the sanitary authorities with the Drinking Water Regulations and good practices; and to assess the performance of the sanitary authority with regard to their statutory duties pertaining to drinking water treatment. The criteria used in the audit were:
◆ The recommendations specified in the Handbooks on Implementation for Sanitary Authorities in relation to the European Communities (Quality of Surface Water Intended for the Abstraction of Drinking Water) Regulations, 1989 and the European Communities (Quality of Water Intended for Human Consumption) Regulations 1988;
◆ The recommendations specified in previous Quality of Drinking Water in Ireland reports;
◆ The European Communities (Quality of Water Intended for Human Consumption) (Amendment) Regulations, 2000, S.I. No 177 of 2000.
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The following sanitary authorities were audited during 2002:
◆ Carlow County Council
◆ Donegal County Council
◆ Dun Laoghaire Rathdown County Council
◆ Galway County Council
◆ Leitrim County Council
◆ Limerick City Council
◆ Limerick County Council
◆ Louth County Council
◆ Mayo County Council
◆ Monaghan County Council
◆ South Tipperary County Council
The audit procedure consisted of an opening meeting with senior management of the sanitary authority, a site inspection of a selected plant, and a closing meeting. The scope and objectives of the audit were outlined at the opening meeting. The site inspection was used to review the general operation of a selected plant. The closing meeting followed the audit and was used to present the audit findings. Subsequent to the audit, a report was issued to each authority. This audit report set out the observations noted during the audit and recommended actions to be taken by the authority concerned. These actions will form part of the criteria to be used in future audits.
In last years report, the EPA noted the absence, in most cases, of documented procedures for dealing with exceedances of the drinking water standards. The EPA is pleased to note that documented procedures for dealing with exceedances of the faecal coliform standard were in place or in preparation in a number of local authorities audited. This is a welcome development. Procedures should be prepared for dealing with exceedances of other standards.
The EPA also notes the development of a draft environmental management and control system in South Tipperary and encourages other sanitary authorities to follow suit. There are many aspects to the management of a drinking water plant and these need to be brought under one umbrella. The Agency recommends a management systems approach to the operation of drinking water treatment facilities and the management of monitoring results, which brings all the relevant strands together. Given the outbreak of crytosporidiosis in Mullingar during 2002 and the three reported cases in Northern Ireland (Glaberman, 2002) the need for a structured approach to the management of a drinking water plant is essential. This approach is necessary to ensure that drinking water is produced using the most up-to-date best practices. The developments in South Tipperary and the development of documented procedures for dealing with exceedances in certain sanitary authorities represents a significant improvement on observations in the previous years findings.
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The following is a compilation of the main observations noted during individual audits which are in need of corrective actions:
◆ Absence of a documented management system in most of the plants visited;
◆ Absence of a documented procedure for dealing with exceedances of the standards in some sanitary authorities;
◆ Some authorities did not have written procedures for sampling drinking water;
◆ Documented monitoring programmes not carried out as specified;
◆ Inadequate monitoring of aluminium in supplies where alum is used as a coagulant;
◆ Delays in communication of results between Health Boards and sanitary authorities;
◆ Poor management of treatment plant sludges at some treatment works;
◆ Inadequate attention to source protection of drinking water at some treatment works.
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5. CURRENT ISSUES
5.1. INTRODUCTION
This section of the report attempts to address the major issues of interest to consumers with regard to drinking water in Ireland. Some of the issues and comments made have already been discussed in previous drinking water reports. However, the EPA is conscious that some consumers may not have read previous reports or indeed their drinking water supply may have changed and that therefore these issues may well be of interest to them.
Current issues discussed below are;
◆ Responsibility for producing and monitoring drinking water
◆ Chlorination
◆ Fluoridation
◆ Bottled water
◆ Quality in rural water schemes; and
◆ Implementation of the 2000 Drinking Water Regulations
A feature of all drinking water reports has been that, in commenting on the topics of greatest current interest, the EPA reminds the reader that any breach of the quality standards laid down in the 1988 Drinking Water Regulations cannot be condoned.
5.2. RESPONSIBILITY FOR PRODUCING AND MONITORING DRINKING WATER
Many consumers are unaware that sanitary authorities (i.e. local authorities) are responsible for the production, monitoring and distribution of their drinking water. A sanitary authority must take all reasonable steps to warn consumers where monitoring of drinking water indicates that there is an unacceptable risk to public health. In the case of a private water supply serving fewer than 50 persons, the authority must issue a notice on the person responsible for the supply advising that person of the measures, which should be taken for the improvement of the quality of the water. Irrespective of supply type (i.e. public, group or private) the sanitary authority has responsibilities where drinking water sources such as rivers, lakes or groundwater are polluted. The Water Pollution Acts 1977-1990 confer considerable powers on local authorities to prevent pollution and also to prosecute offenders, where pollution has occurred.
The EPA has the duty of preparing an annual report on the quality of drinking water in Ireland and to make appropriate recommendations. This report is based on the monitoring returns submitted by sanitary authorities, whose function it is to monitor such waters.
5.3. CHLORINATION
Chlorine (or appropriate compounds of it) is undoubtedly the most important chemical used in water
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treatment in Ireland today, and has been for a long time past. Although a highly poisonous gas in its pure form and a powerful oxidising agent, chlorine in very dilute solution is a most effective agent for the disinfection of water. It is very efficient at destroying those bacteria which originate in human or animal waste and which cause wholly undesirable and dangerous contamination of drinking water.
Among these micro-organisms are the specific types, termed "pathogenic" (or disease-causing), which are responsible for a wide range of water-borne diseases such as polio, cholera, typhoid fever, hepatitis, salmonella and so on. The consequences of pathogenic contamination are usually most dramatically and cruelly demonstrated by the cholera epidemics which almost invariably follow natural disasters, especially in poorer, developing countries. While such diseases are not endemic in Ireland, nonetheless serious health problems - and mortality - can be caused by sewage - or slurry-contaminated drinking water. Disinfection is accordingly the single most important stage of water treatment.
There are various difficulties and problems associated with the use of chlorine. Because of its reactivity chlorine will interact with any dissolved organic matter in a water to be disinfected, notably the agents which cause natural colour. This chemical activity may result in the production of excessive trihalomethanes and causes the consumption of some of the added chlorine leading to less chlorine remaining to carry out the required disinfection. The obvious action in such cases is to increase the chlorine dosage so as to cater for the so-called "chlorine demand" of the water (i.e. the amount of chlorine promptly absorbed by reactions with dissolved matter) and also to meet the requirements for effective disinfection. However, unless this is done with great care, the resultant post-reaction chlorine levels may either be too high (in which case the consumers will perceive the odour and/or taste of chlorine) or too low, in which case the disinfection may be incomplete. The lesser of these two "evils" is the former - it is safer for the consumer to receive water with slightly too much chlorine in it than the opposite. If a water still has chlorine in it as it reaches the consumer, then there will have been continuing protective disinfection all the way along the mains from the treatment works to the consumer’s tap.
There are more efficient alternatives to chlorine, the primary processes being ozonation and ultra-violet treatment. These have the major benefit that they are effective in removing organisms unaffected by routine chlorination. Ozonation consists of the treatment of water with ozone [O3] - a highly reactive form of oxygen - which is electrically generated at the point of disinfection, while ultra-violet [UV] treatment consists of passing the water along a chamber through which a UV light of suitable intensity is shone. These more effective procedures have, however, one major deficiency as compared with chlorination - there is no residual protection against re-infection of the water (say, by seepage of a contaminant through a cracked main).
The use of chemical disinfectants such as chlorine in water treatment will typically result in the formation of by-products, some of which are potentially hazardous. The World Health Organisation (2000) advises that " the risks to health from these by-products at the levels at which they occur in drinking water are extremely small in comparison with the risks associated with inadequate disinfection. Thus, it is important that disinfection not be compromised in attempting to control such by-products".
In summary, where disinfection forms part of the preparation and/or distribution of water intended for human consumption, the EPA recommends that sanitary authorities should ensure that the efficiency of the disinfection process is verified and that any contamination from disinfection by-products is kept as low as possible. Control strategies to reduce disinfection by-products should in the first instance concentrate on organic precursor removal using colour as a guide. Finally, it remains to reassure the consumer that, in spite of the fact that chlorine itself is toxic, and contrary to occasional scare reports about the "hazards" of
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chlorine, there is no risk of chlorine toxicity from drinking water which has been so disinfected. By the time a water could be regarded as directly hazardous from excess chlorine, it would taste and smell foul and be utterly repellent to the consumer.
5.4. FLUORIDATION
The basis for the use of fluoride in the treatment of major Irish public water supplies arises from the Health (Fluoridation of Water Supplies) Act, 1960, which requires health authorities to fluoridate public water supplies so as to achieve a concentration range of 0.8 - 1.0 mg/l fluoride as F. The aim of adding fluoride was to bring about a reduction in tooth decay (dental caries) in children, the lower limit of 0.8 mg/l being considered by expert opinion as the threshold below which no benefits could be achieved. Similarly, 1.0 mg/l was considered the upper limit of effectiveness. Reports at that period suggested that at concentrations from around 2 mg/l F upwards negative effects of increasing severity occurred.
The 1980 (and indeed the 1998) Drinking Water Directive specified an upper limit of 1.5 mg/l for drinking water, but in making the 1988 (and 2000) Regulations, the Minister for the Environment took the existing Irish legislation into account and set an upper limit of 1.0 mg/l F. Thus, the limit in Ireland is two-thirds of that permissible elsewhere in the EU.
The type, form, quality and purity of fluoride to be added to Irish public piped water supplies is set out in the Health (Fluoridation of Water Supplies) Act, 1960. Under this Act the health authorities arrange for the fluoridation of water supplied to the public by sanitary authorities. Though the Department of the Environment and Local Government sets the drinking water standards the Department has consistently relied upon the advice of the Department of Health and Children with regard to the limit imposed for fluoride.
In recognition of the public interest in fluoridation, the Minister for Health and Children set up a Forum on Fluoridation in May 2000. The membership of the Forum comprised representatives of a wide spectrum of interests including academic, dental, public health, environmental protection and consumer representatives. The terms of reference of the Forum were:
◆ to review the fluoridation of public piped water supplies and the programme of research being undertaken on behalf of health boards in the area; and
◆ to report and to make recommendations to the Minister for Health and Children.
The findings of the Forum on Fluoridation were published in September 2002. The primary conclusions in relation to the fluoridation of public water supplies in Ireland were;
◆ water fluoridation has been very effective in improving the oral health of the Irish population, especially of children but also of adults and the elderly;
◆ the best available and most reliable scientific evidence indicates that at the maximum permitted level of fluoride in drinking water at 1 part per million, human health is not adversely affected;
◆ dental fluorosis (a form of discoloration of the tooth enamel) is a well-recognised condition and an indicator of overall fluoride absorption, whether from natural sources, fluoridated water or from the inappropriate use of fluoride toothpaste at a young age. There is evidence that the
103 Quality of Drinking Water in Ireland A Report For The Year 2001
prevalence of dental fluorosis is increasing in Ireland. The main recommendations in relation to policy aspects of water fluoridation were:
◆ the fluoridation of piped public water supplies should continue as a public health measure, subject to the other recommendations contained in the Forum’s report;
◆ in light of the best available scientific evidence, the Fluoridation of Water Supplies Regulations, 1965 should be amended to redefine the optimal level of fluoride in drinking water from the present level (0.8 to 1.0 ppm) to between 0.6 and 0.8 ppm, with a target value of 0.7 ppm;
◆ the amended Regulations should reflect advances in the technology of fluoride monitoring and testing and also the most recent international specifications for the quality of the products used in the fluoridation process;
◆ an Expert Body should be established to implement the recommendations of the forum and to advise the Minister for Health and Children on an ongoing basis on all aspects of fluoride and its delivery methods as an established health technology.
Technical aspects of water fluoridation recommended were:
◆ guidelines/codes of practice and audit processes should be developed to support ongoing quality assurance of all aspects of the water fluoridation process and should take account of both Irish and international research;
◆ external audit procedures of existing fluoridation plants should be put in place to monitor the performance of fluoridation plants and should be part of the specification of new plants. Audit results should be included in annual reports on water fluoridation produced by relevant fluoride monitoring committees;
◆ the standards and quality of each fluoridation plant should be assessed and decisions made as to the appropriateness of the continued use of inefficient plants;
◆ fluoride monitoring, analytical and reporting procedures should be updated to reflect modern technologies and to facilitate the timely reporting of all drinking water fluoride levels. The results should be made available in a format so that compliance with regulations can be monitored. These results should be freely available for public scrutiny;
◆ raw water should be checked for fluoride levels before fluoridation takes place in compliance with the current regulations;
◆ the Eastern Regional Health Authority, currently responsible for purchasing the fluoridating products on behalf of the country’s health boards, should ensure compliance with the amended regulations specifying the quality standards of the products used in the fluoridation process.
The report of the Forum on Fluoridation also contains several other recommendations in relation to fluoride toothpaste, oral health care industry, infant formula, fluoride research, education, information and public participation, public health and professional practice. These recommendations are considered outside the remit of an assessment of the quality of drinking water in Ireland and as such will not be discussed here. A full copy of the report is available to download from the website of the Forum on
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Fluoridation (www.fluoridationforum.ie). 5.5. BOTTLED WATER
The regulation of bottled water in Ireland is somewhat complicated at present. There are three different types of water that can be described as bottled water: natural mineral water (NMW), spring water and other waters. Natural mineral water must meet the requirements of the Natural Mineral Water Directive (80/777/EEC as amended by 96/70/EC), which was transposed into Irish law by the European Communities (Natural Mineral Waters) Regulations, 1986 (S.I. No. 11 of 1986) and the European Communities (Natural Mineral Waters) (Amendment) Regulations, 1998 (S.I. No. 461 of 1998). Producers of natural mineral water must also notify the National Standards Authority of Ireland (NSAI). Spring water must meet the requirements of the NMW Directive as well as the requirements of the European Communities (Quality of Water intended for Human Consumption) Regulations 1988, although there is no requirement for producers of spring water to notify the NSAI. At present Environmental Health Officers, who are authorised officers under the Food Safety Authority of Ireland Act, 1998 carry out random checks of the microbiological and chemical composition of both natural mineral waters and spring waters. Bottled Water (other than natural mineral water or spring water) in Ireland is currently governed by the European Communities (Quality of Water intended for Human Consumption) Regulations 1988. Flavoured water is classified as a soft drink and therefore does not come under the remit of the Natural Mineral Water Directive.
The regulatory situation is expected to change in January 2004 because "water supplied in bottles and containers" is specifically excluded from the definition of "water intended for human consumption" as set out in the European Communities (Drinking Water) Regulations, 2000. This means that "water supplied in bottles or containers" will not be regulated under the EC (Drinking Water) Regulations, 2000. In the future all bottled waters (i.e. natural mineral waters, spring waters, still and sparkling waters and any other bottled waters) are likely to be regulated by legislation currently being prepared by the Department of Health and Children, which will result in the current Natural Mineral Water Regulations being revoked.
5.6. QUALITY IN RURAL WATER SCHEMES
Successive Reports on Drinking Water Quality in Ireland have highlighted the great gulf in quality levels between the public supplies and group schemes. Taking bacteriological quality as the most important and relevant indicator, it has been found that the public supplies are for the most part free of recurrent problems, while significant numbers of the group supplies are contaminated to a greater or lesser extent and are not fit for human consumption as required by the Drinking Water Regulations. Indeed some group schemes are of such inferior microbiological quality that permanent "boil notices" are issued to consumers in order to alleviate immediate risks.
Public water schemes are administered by sanitary authorities whereas group schemes/supplies are "private supplies" and are administered and managed by the consumers of the supply. Group water schemes are further classified as either "public group schemes" or "private group schemes" depending on the source of the water distributed to their member. The former obtain their water from a public sanitary authority supply, the committees undertaking distribution, while the latter distribute (with or without treatment) water which is obtained from a private source.
Typical problems encountered by group water schemes are illustrated below by real examples of schemes that could be found anywhere in Ireland (Spain, 2000). The source of Scheme A is located adjacent to the hard margin of a national secondary road and a heavy duty unsealed manhole cover is all that is offered
105 Quality of Drinking Water in Ireland A Report For The Year 2001
as source protection. During periods of heavy rainfall, surface water seeps into the borehole contaminating the supply. In Scheme B, the source of drinking water for a scheme of 15 houses is located in the garden of one house. The area does not have a sewer network and houses are individually serviced by septic tank systems. In a final example, Scheme C, a spring source for 200 households is located on the flood plain of a river. The protection for the spring is a 900 mm concrete pipe and cover, sunk 600 mm into the soil surface. Cattle are wintered adjacent to the source and invariably contaminate the source during this time. These examples illustrate the types of problems facing group schemes.
In recent years there has been a major drive to tackle the quality deficiency in group water schemes. The problems are being tackled by a number of relevant parties including the operators of the group schemes themselves, the sanitary authorities, the Department of the Environment and Local Government, the National Federation of Group Water Schemes (set up in early 1997), FÁS (the national training authority) and the EPA. All areas of relevance are under scrutiny including sources, distribution, analytical programmes and services, full definition of quality problems, management aspects, treatment options and costings. The effort is being matched by a commitment of €644 million under the National Development Plan 2002-2006.
The EPA 2000 drinking water report welcomed the introduction of a Quality Assurance Scheme by the National Federation of Group Water Schemes. The model adopted by the Federation is the HACCP (Hazard Analysis Critical Control Points) system which operates in the food industry. This system will involve setting minimum standards for the supply of drinking water. Where individual group schemes achieve certain minimum standards in the management of a drinking water supply they will achieve certification under the scheme. The model puts in place a system which is preventative and proactive as opposed to one based on crisis management. Indeed this system should also provide confidence to consumers that relevant legislation and national guidelines are being followed and that satisfactory drinking water is being delivered.
Though the commitment of monies in the National Development Plan is to be welcomed the principle underpinning the Water Framework Directive that the prevention of water pollution is better than cure should be paramount. The current absence of a quality assurance scheme should not in itself be an excuse for failing to take the requisite steps to reduce the risk of a drinking water supply being unsafe. To this end the following protocol should be established by those managing a group water scheme:
◆ all equipment and plant should be maintained in good working condition;
◆ raw water sources and storage containers should be inspected frequently for any source of contamination (e.g. animals and/or birds);
◆ disinfection equipment should be subjected to routine maintenance;
◆ a system should be developed for prompt notification to all consumers (including visitors) where drinking water standards have been exceeded;
◆ records of all servicing equipment and routine inspections should be maintained; and
◆ people engaged in the management and upkeep of equipment and plant should be properly trained.
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5.7. IMPLEMENTATION OF THE 2000 DRINKING WATER REGULATIONS AND IMPROVED COMMUNICATION
As mentioned in chapter one of this report the European Communities (Drinking Water) Regulations, 2000 will come into effect in Ireland on the 1 January, 2004 in compliance with the requirements of the EU Drinking Water Directive (98/83/EC). The 2000 Regulations will introduce radical changes to the monitoring and management of drinking waters, compared to that which is current under the 1988 Regulations. The changes include the sample numbers, the parameters to be monitored, the sampling regime as well as the extent of coverage. To assist in the transition process, the Department of Environment and Local Government has appointed consultants to work with all local authorities during 2003 and 2004 towards the establishment of a Drinking Water National Monitoring Programme. To ensure that a programme is put in place that is in compliance with the Regulations, surveys of all relevant drinking water supply systems in the country will need to be undertaken. It will be necessary to quantify sampling, analysis requirements and existing laboratory capacity. The EPA welcomes this initiative and in particular the holistic approach adopted. The EPA has previously recommended that local authorities should post drinking water results to their respective websites on a monthly basis. This is necessary, as there is considerable interest on the part of the general public in drinking water monitoring results. In this regard the EPA welcomes the presence of drinking water monitoring information on the Cork, Galway and Kerry County Council websites, although the most recent monitoring information relates to 2001. The Department’s initiative includes the electronic capture of data and this is the first step towards putting in place a national network of up-to-date drinking water information for the general public.
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6. CONCLUSIONS
This section of the report provides a series of conclusions based on the 22,453 samples taken and 146,352 tests conducted by sanitary authorities in 2001. The conclusions are broadly divided into observations made on the overall quality of public water supplies (i.e. drinking water produced by local authorities) and group water schemes (i.e. water distributed by private individuals or committees). The separate conclusions for public and group water supplies should not be interpreted as meaning that different standards apply or indeed should be tolerated. The smallest of supplies reported on is of the greatest importance to those who are its consumers, and any risk to the latter is to be condemned just as much as would be the case if larger numbers of consumers were served. The broad division of supply type (PWS or GWS) made in previous EPA reports is intended to highlight the quality deficiencies observed in group water schemes. The quality deficiency in this sector has been acknowledged by Government which has committed €644 million in the National Development Plan to tackle this issue. The EPA will continue to make separate conclusions on public and group water schemes until the quality deficiency in the group water scheme sector has been addressed.
The following are the conclusions of this report:
1. The overall quality of the 904 public drinking water supplies monitored and reported on in 2001 (producing 92.0% of the monitored drinking water) continues to be satisfactory. On the other hand, the overall quality of the 1,536 group water supplies monitored in 2001 (producing 7.9% of the monitored drinking water) remains unsatisfactory.
2. Analysis of the exceedances of the faecal coliforms standard on a scheme by scheme basis indicates that 720 (79.6%) public water supplies and 1,051 (68.4%) group water schemes monitored were free of faecal contamination in 2001. Conversely, 184 public water supplies and 485 group water schemes exhibited some degree of faecal contamination during 2001, although the majority of exceedances recorded were moderate in nature.
3. For faecal coliforms, the most important public health indicator, the compliance rate for samples taken from public water supplies in 2001 was 97.2%, up from 96.7% in 2000. This means that, in 2001, 422 samples out of 15,117 samples analysed, exceeded the standard. In contrast, the compliance rate for samples taken from group water schemes in 2001 was 74.1%, up from 70.8% in 2000. This means that, in 2001, 1,073 samples out of 4,148 samples analysed exceeded the standard. While there was an improvement in the overall compliance rate for group water schemes, overall quality remains poor.
4. There were 52 serious incidents of faecal coliform contamination (i.e. > 20 cfu/100 ml) in public water supplies in 2001. In 25 (48%) of these cases drinking water quality was not retested within 7 days of the incident being detected. Indeed, for 5 of these incidents no follow up action was reported.
5. Because of the limited monitoring of most group water schemes it is very difficult to characterise the overall quality of a scheme. However, there were 373 serious incidents of faecal coliform contamination (i.e. > 20/100 ml) reported in group water schemes in 2001.
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6. There was an increase of 3% in the number of tests carried out by sanitary authorities in 2001, as compared to 2000. This was primarily due to a significant increase in the numbers of samples analysed for heavy metals in 2001. Overall, the number of tests carried out has increased almost 110% in a ten year period.
7. There were 138,008 tests in compliance with the specified drinking water standards, with an overall compliance rate of 94.3%. Compliance was less than 94.4% for total coliforms, aluminium, manganese, colour and faecal coliforms. Compliance was greater than 99% for ammonium, nitrates, nitrites and heavy metals.
8. Compliance with the aluminium standard remains low at 91.2% in public water supplies in 2001, down from 92.0% in 2000. There are several treatment plants where compliance with the aluminium standard is poor and indeed in a number of supplies every sample analysed for aluminium exceeded the standard in 2001.
9. Overall, compliance with the nitrate standard remained good in 2001 (99.1% compliance). However, it was noted that several supplies which were reported as exceeding the nitrate standard in previous reports continued to do so in 2001.
10. In general, sanitary authorities address exceedances of the drinking water standards using informal/adhoc procedures. Random audits of local authorities by the EPA indicate that in some instances corrective actions were not always put in place as a result of values found to be in excess of the drinking water standards.
11. There are several reasons why an exceedance of a water quality standard may occur. These include the contamination of the raw water or inadequacies of the treatment process. However, many exceedances occur because of deficiencies in the distribution network or because of work being undertaken on the distribution network. Many of these exceedances could be avoided if regular scouring of the network is undertaken or proper management is in place during civil works on the distribution network.
12. There is clear evidence from this and previous reports that water supplied by sanitary authorities is safer to drink than water supplied by group water schemes.
13. Group water schemes, on average, serve much smaller populations than public water schemes and are considerably more numerous than public water schemes. There are considerable logistical problems associated with having large numbers of small supplies. These include operational and management difficulties for those responsible for the production and supply of drinking water as each individual supply requires management, maintenance and monitoring.
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7. RECOMMENDATIONS
In this section specific recommendations are made in relation to the operation of drinking water plants, monitoring and reporting, and management of results. These recommendations are a result of both the analysis of the monitoring returns for 2001 and of EPA audits conducted during 2002. Some of these recommendations have been included in previous drinking water reports. However, it is considered necessary to repeat them as they constitute best practice for dealing with deficiencies in drinking water supplies and for reporting the quality of such supplies.
7.1. MANAGEMENT OF DRINKING WATER
1. A documented management systems approach should be adopted to the management and operation of drinking water treatment plants to ensure that treatment objectives are achieved.
The management system should address: (as a minimum)
◆ organisation and responsibilities of personnel involved in the production of drinking water;
◆ quantification of the environmental effects of the treatment plant;
◆ operational control of the treatment plant;
◆ documentation and maintenance records of the treatment plant;
◆ audits of the plant;
◆ preventative maintenance;
◆ routine servicing;
◆ emergency response;
◆ equipment replacement; and
◆ monitoring programme and frequency of analysis.
2. Group water schemes should obtain certification under the Hazard Analysis Critical Control Points (HACCP) system adopted by the National Federation of Group Water Schemes. For smaller public drinking water schemes a certification system similar to the HACCP system should be pursued in order to minimise risks. Where the quality model adopted by the Federation of Group Water Schemes is not in place, those responsible for group water schemes should prepare a protocol in order to reduce the risk of an unsafe drinking water supply. Further information on what should be included in such a protocol is contained in section 5.6 of this report.
3. Suppliers of drinking water should ensure that the efficiency of the disinfection process is verified and that any contamination from disinfection by-products (e.g. trihalomethanes) is kept to a minimum.
110 Quality of Drinking Water in Ireland A Report For The Year 2001
4. Plants which consistently produce drinking water which is in breach of the standards specified in the Regulations, should be clearly identified by the responsible authority and a corrective action programme developed to bring the supply into compliance. This is particularly relevant in the case of aluminium (which is used as a coagulant). Supplies that have consistent exceedances of the aluminium standard should be examined by the sanitary authority as a matter of priority as alum is used as a coagulant and, as such, levels of aluminium in the treated water are entirely within the control of the plant operator. Corrective action programmes should be put in place to ensure that the supply is brought into compliance with the Regulations.
5. All sanitary authorities should have a protocol in place for dealing with exceedances of the drinking water standards. Such a protocol should ensure that appropriate steps are taken to remedy an exceedance as soon as possible.
6. Supplies where nitrate exceedances are reported should be investigated by the responsible authority. Source protection measures should be put in place where possible to remove possible sources of contamination immediately. Where such measures are impractical or are not successful in reducing the levels of nitrate in the supply to ensure compliance with the standard, an alternative source of water for the supply should be sought.
7. Design Build and Design Build and Operate contracts are becoming increasing popular in the water industry. Such contracts should require the development of an environmental management system to operate a drinking water plant. This approach will facilitate the sanitary authority in determining on an on-going basis if best practice is being implemented in the production of drinking water.
8. Personnel involved in the production of drinking water should receive on-going training. In particular, training in the protection of drinking water supplies against contamination from Cryptosporidium and other related micro-organisms should be provided.
7.2. MONITORING AND REPORTING
1. The sampling and analysis of drinking water should be undertaken by those competent to do so. The use of an approved or accredited laboratory is recommended. The use of laboratories participating in the EPA intercalibration programme is encouraged.
2. A sampling programme should be developed each year that is consistent with the requirements of the Regulations. A documented procedure should be in place for sampling of drinking water.
3. Exceedances of the standards in the drinking water Regulations should be investigated and follow-up samples should be taken as soon as is practicable following the original non-compliant sample (the incident). Sampling should continue until the supply has been returned to compliance with the drinking water standards. When reporting monitoring results to the EPA, sanitary authorities should clearly distinguish between routine sampling and sampling following an incident.
4. A risk assessment should be carried out by each sanitary authority to determine the vulnerability of public water supplies to Cryptosporidium, commencing with the larger water treatment plants, to identify plants which are in need of upgrading. Monitoring for Cryptosporidium should be
111 Quality of Drinking Water in Ireland A Report For The Year 2001
initiated on a more widespread basis with particular attention focussing on surface water supplies that have no treatment except disinfection.
5. The Agency recommends that sanitary authorities carry out an assessment on their ground water supplies to determine where compliance with the new arsenic standard is likely to be problematic.
6. The Agency recommends that sanitary authorities conduct an audit of the use of lead piping in their functional areas to determine the likely risk of exceedances of the new lead standard occurring.
7. In relation to the new pH standard, the Agency recommends that sanitary authorities investigate the implications of the new standard for water supplies in their functional area. Lime pH correction may be required in some treatment plants that use coagulation because of the lower levels of pH.
7.3. COMMUNICATION
1. The results of monitoring of drinking water submitted under Section 58 of the EPA Act, 1992 should be submitted in the format requested by the Agency.
2. There is considerable interest in the annual drinking water report. This interest is to be welcomed. The number of analytical results now accounts for some 22,453 samples (146,352 individual tests). There is an increasing trend towards the use of electronic databases to manage such results. Where databases are being used or will be used in the near future consideration should be given to including drinking water results on a monthly basis on local authority websites.
3. Drinking water data should be reported electronically each year to the EPA by the 2nd April. This timeframe allows each sanitary authority up to three months to submit the data and enables the EPA to prepare a national report for publication before the end of that calendar year.
7.4. INFRASTRUCTURE AND PLANNING
1. The large number of small group water schemes in Ireland, and to a lesser extent, small public supplies, is a significant barrier to improving the quality of drinking water. Large numbers of small supplies result in operational and management difficulties for those responsible for the production and supply of drinking water, as each individual supply requires management, maintenance and monitoring. Consideration should therefore be given to rationalising water supply in parts of Ireland with large numbers of small supplies with a view to reducing the overall number of supplies and increasing their average size.
2. Successive EPA reports on the quality of drinking water in Ireland provide clear evidence that water supplied by sanitary authorities is safer to drink than water supplied by privately operated group schemes. Where persistent problems with group schemes exist, serious consideration should be given to having these group schemes brought under the control of sanitary authorities.
112 Quality of Drinking Water in Ireland A Report For The Year 2001
8. Suggested Further Reading
Bouchier et al. (1998). Cryptosporidium in Water Supplies: Third Report of the Group of Experts. Department of Environment, Transport and the Regions.
Council Directive 98/83/EC of 3 November 1998 on the Quality of Water Intended for Human Consumption.
Council Directive 80/778/EEC of 30 August 1980 on the Quality of Water Intended for Human Consumption.
Council Directive 80/777/EEC of 15 July 1980 on the Approximation of the Laws of the Member States relating to the Exploitation and Marketing of Natural Mineral Waters.
Department of the Environmental and Local Government. (1998). Protection of Water Supplies: Guidelines for Local Authorities on minimising the risk of Cryptosporidium in water supplies. Circular L7/98.
Department of Health and Children (2002). Forum on Fluoridation 2002.
Environmental Protection Agency (2001). Parameters of Water Quality: Interpretations and Standards.
Environmental Protection Agency (2001). The Quality of Drinking Water in Ireland: A Report for the Year 2000 with a Review of the Period 1998 to 2000.
Environmental Protection Agency Act, 1992 (No. 7 of 1992)
Environmental Research Unit (1990). European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988 Ð A Handbook on Implementation for Sanitary Authorities.
European Communities (Drinking Water) Regulations, 2000 (SI No. 439 of 2000)
European Communities (Natural Mineral Water) Regulations, 1986 (SI No. 11 of 1986)
European Communities (Natural Mineral Water) (Amendment) Regulations, 1986 (SI No. 461 of 1998)
European Communities (Quality of Surface Water Intended for the Abstraction of Drinking Water) Regulations, 1989 (SI No. 294 of 1989)
European Communities (Quality of Water Intended for Human Consumption) (Amendment) Regulations, 2000 (SI No. 177 of 2000)
European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988 (SI No. 81 of 1988)
Glaberman, S., Moore, J.E., Lowery, C.J., Chalmers, R.M., Sulaiman, I., Elwin, K., Rooney, P.J., Millar, B.C., Dooley, J.S.G, Lal, A. A., and Xiao, L. (2002). Three Drinking-WaterÐAssociated Cryptosporidiosis Outbreaks, Northern Ireland. http://www.cdc.gov/ncidod/EID/vol8no6/01-0368.htm
113 Quality of Drinking Water in Ireland A Report For The Year 2001
Health (Fluoridation of Water Supplies) Act, 1960 (No. 46 of 1960)
National Academy of Sciences (2001). Arsenic in Drinking Water: 2001 Update.
National Disease Surveillance Centre. (2002). Draft Report on Waterborne Cryptosporidiosis Subcommittee of the Scientific Advisory Committee. National Disease Surveillance Centre.
National Standards Association of Ireland (1992). I.S. 432:1992 Bottled Water.
Spain, R (2002). Group Water Schemes Bacteria Problem Ð A Local Authority Perspective. Proceedings of the International Group of Hydrogeologists (Irish Group) Seminar 16-17th April 2002.
World Health Organisation (2000). Disinfectants and Disinfection Byproducts: IPSC Environmental Health Criteria 216.
World Health Organisation (1993). Guidelines for Drinking Water Quality. (2nd Ed).
114 APPENDIX A Drinking Water Regulations Parameter Units MAC Remarks Parameter Units MAC Remarks Parameters and Standards 21 Hydrogen Sulphide µg/l S Undetectable 47 Polycyclic µg/l 0.2 organoleptically Aromatic Parameter Units MAC Remarks 22 Substances Extractable in mg.l dry No significant Hydrocarbons Chloroform residue increase above A. ORGANOLEPTIC PARATMETERS background level A. MIRCOBIOLOGICAL PARAMETERS 23 Dissolved or Emulsified µg/l 10 * After extraction 1 Colour mg.l 20 by petroleum ether 48 Total Coliforms no/100 ml 0 Mem Filter method Pt/Co 24 Phenols [Phenol Index] µg/l 0.5 Excluding phenols MPN<1 Mult Tube method 2Turbidity mg/l 10 C6H5OH which do not react 49 Faecal Coliforms no/100 ml 0 Mem Filter method SiO2 to chlorine MPN<1 Mult Tube method Jackson 4 Nephelometric units 25 Boron µg/l B 2000 50 Faecal no/100 ml 0 Mem Filter method 3 Odour Dilution 2 At 12¼ C 26 Surfactants [Reacting to µg/l 200 Streptococci MPN<1 Mult Tube method No. 3 At 25¼ C Methylene Blue] lauryl 51 Sulphite Reducing no/20 ml MPN<1 Mult Tube method 4Taste Dilution 2 At 12¼ C sulphate Clostridia No. 3 At 25¼ C 27 Other Organochlorine µg/l 100 Haloform 52 Total Bacteria no/1 ml No Counts at Compounds [not covered concentrations Counts for Water significant 37¼C and B. PHYSICO-CHEMICAL PARAMETERS by parameter No 46] must be as low Supplied for increase Counts at 22¼C as possible Human above 5Temperature ¼C 25 28 Iron µg/l Fe 200 Comsumption background 6 Hydrogen Ion pH units 6.0-9.0 The water should not be 29 Manganese µg/l Mn 50 levels aggressive; the pH values 30 Copper µg/l Cu 500 53 Total Bacteria no/1 ml 20 Counts at 37¼C do not apply to water in 31 Zinc µg/l Zn 1000 Counts for Water closed containers 32 Phosphorus µg/l P2O5 5000 in Closed Containers 100 Counts at 22¼C 7 Conductivity µS/cm 1500 Corresponding to 33 Fluoride µg/l F 1000 @20¼C 1650 @ 25¼C 34 Suspended solids mg/l No persistently See below for MRC values for softened water. 8 Chlorides mg/l Cl 250 visible suspended 9 Sulphates mg/l SO4 250 solids 10 Calcium mg/l Ca 200 35 Barium µg/l Ba 500 B. MINIMUM REQUIRED CONCENTRARTION FOR SOFTENED 11 Magnesium mg/l Mg 50 36 Silver µg/l Ag 10 WATER INTENDED FOR HUMAN CONSUMPTION 12 Sodium mg/l Na 150 13 Potassium mg/l K 12 A. PARAMETERS CONCERNING TOXIC SUBSTANCES 1Total Hardness mg/l Ca 60 Calcium or equivalent 14 Aluminium mg/l Al 0.2 cations 15 Dry Residues mg/l 1000 Dried @ 180¼C 37 Arsenic µg/l As 50 2 Alkalinity mg/l HCO3 30 The water should not 38 Cadmium µg/l Cd 5 be aggressive C. PARAMETERS CONCERNING SUBSTANCES 39 Cyanides µg/l CN 50 UNDESIRABLE IN EXCESSIVE AMOUNTS 40 Chromium µg/l Cr 50 Note 1: The MAC is 500 µg/l at outlets of pumping and/or treatment works 41 Mercury µg/l Hg 1 and substations. A MAC of 3000 µg/l is applicable after the water 16 Nitrates mg/l NO3 50 = 11.3 mg/l N 42 Nickel µg/l Ni 50 has been standing for 12 hours in the piping at the point where it is 17 Nitrites mg/l NO2 0.1 = 0.03 mg/l N 43 Lead µg/l Pb 50 In running water made available to the consumer. 18 Ammonium mg/l NH4 0.3 = 0.23 mg/l N 44 Antimony µg/l Sb 10 Note 2: The MAC is 1000 µg/l at outlets of pumping and/or treatment works 19 Kjeldahl mg/l N 1 Excl N in NO2/NO3 45 Selenium µg/l Se 10 and substations. A MAC of 5000 µg/l is applicable after the water Nitrogen 46 Pesticides & Related µg/l 0.1 Substances has been standing for 12 hours in the piping at the point where it is 20 Oxidisability mg/l O2 5 Measured when heated Products considered made available to the consumer. in acid separately µg/l 0.5 Total of all substs. Quality of Drinking Water in Ireland A Report For The Year 2001
Appendix B: Extract from S.I. No 439 of 2000 European Communities (Drinking Water) Regulations, 2000
SCHEDULE Part 1 PARAMETERS AND PARAMETRIC VALUES TABLE A: MICROBIOLOGICAL PARAMETERS Parameter Parametric value (number/100 ml) 1 Escherichia coli (E.coli) 0 2 Enterococci 0
TABLE B: CHEMICAL PARAMETERS Parameter Parameter Unit Comments value 3 Acrylamide 0.10 µg/l Note 1 4 Antimony 5.0 µg/l 5 Arsenic 10 µg/l 6 Benzene 1.0 µg/l 7 Benzo(a)pyrene 0.010 µg/l 8 Boron 1.0 mg/l 9 Bromate 10 µg/l Note 2 10 Cadmium 5.0 µg/l 11 Chromium 50 µg/l 12 Copper 2.0 mg/l Note 3 13 Cyanide 50 µg/l 14 1,2-dichloroethane 3.0 µg/l 15 Epichlorohydrin 0.10 µg/l Note 1 16 Fluoride 1.0 mg/l Note 11 17 Lead 10 µg/l Notes 3 and 4 18 Mercury 1.0 µg/l 19 Nickel 20 µg/l Note 3 20 Nitrate 50 mg/l Note 5 21 Nitrite 0.50 mg/l Note 5 22 Pesticides 0.10 µg/l Notes 6 and 7 23 Pesticides Ð Total 0.50 µg/l Note 6 and 8 24 Polycyclic aromatic hydrocarbons 0.10 µg/l Sum of concentrations of specified compounds; Note 9 25 Selenium 10 µg/l 26 Tetrachloroethene and 10 µg/l Sum of concentrations Trichloroethene of specified parameters. 27 Trihalomethanes Ð Total 100 µg/l Sum of concentrations of specified compounds; Note 10 28 Vinyl chloride 0.50 µg/l Note 1
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Notes
Note 1: The parametric value refers to the residual monomer concentration in the water as calculated according to specifications of the maximum release from the corresponding polymer in contact with the water. Note 2: For the water referred to in sub-articles 6 (a), (b) and (c) the parametric value to be met by 1 January, 2004 is 25 µg/l. A value of 10 µg/l must be met by 25 December, 2008. Note 3: The value applies to a sample of water intended for human consumption obtained by an adequate sampling method* at the tap and taken so as to be representative of a weekly average value ingested by consumers and that takes account of the occurrence of peak levels that may cause adverse effects on human health. *The Copper, Lead and Nickel parameters shall be monitored in such a manner as the Minister shall determine from time to time. Note 4: For water referred to in sub-articles 6 (a), (b) and (c), the parametric value to be met by 1, January 2004 is 25 µg/l. A value of 10 µg/l must be met by 25 December, 2013. All appropriate measures shall be taken to reduce the concentration of lead in water intended for human consumption as much as possible during the period needed to achieve compliance with the parametric value. When implementing the measures priority shall be progressively given to achieve compliance with that value where lead concentrations in water intended for human consumption are highest. Note 5: Compliance must be ensured with the conditions that [nitrate]/50 + [nitrite]/3 < 1, the square brackets signifying the concentrations in mg/l for nitrate (NO3) and nitrite (NO2) and the value of 0.10mg/l for nitrites ex water treatment works. Note 6: Only those pesticides which are likely to be present in a given supply require to be monitored. "Pesticides" means: - organic insecticides, - organic herbicides, - organic fungicides, - organic nematocides, - organic acaricides, - organic algicides, - organic rodenticides, - organic slimicides, - related products (inter alia, growth regulators) and their relevant metabolites, degradation and reaction products. Note 7: The parametric value applies to each individual pesticide. In the case of aldrin, dieldrin, heptachlor and heptachlor epoxide the parametric value is 0.030 µg/l. Note 8: "Pesticides Ð Total" means the sum of all individual pesticides detected and quantified in the course of the monitoring procedure; Note 9: The specified compounds are: - benzo(b)fluoranthene - benzo(k)fluoranthene - benzo(ghi)perylene - indeno(1,2,3-cd)pyrene. Note 10:The specified compounds are: chloroform, bromoform, dibromochloromethane and bromodichloromethane. For the water referred to in sub-articles 6 (a), (b) and (c), the parametric value to be met by 1 January, 2004 is 150 µg/l. A value of 100 µg/l must be met by 25 December, 2008.
117 Quality of Drinking Water in Ireland A Report For The Year 2001
All appropriate measures must be taken to reduce the concentration of THMs in water intended for human consumption as much as possible during the period needed to achieve compliance with the parametric value. When implementing the measures to achieve this value, priority must progressively be given to those areas where THM concentrations in water intended for human consumption are highest. Note 11:The parametric value is 1.0mg/l for fluoridated supplies. In the case of supplies with naturally occurring fluoride the parametric value is 1.5mg/l.
TABLE C: INDICATOR PARAMETERS Parameter Parameter Unit Comments value 29 Aluminium 200 µg/l 30 Ammonium 0.30 mg/l 31 Chloride 250 mg/l Note 1 32 Clostridium perfringens 0 number/100 Note 2 (including spores) ml 33 Colour Acceptable to consumers and no abnormal change 34 Conductivity 2500 uS cm-1 at Note 1 20ûC 35 Hydrogen ion concentration ≥ 6.5 and ≤9.5 pH units Note 1 36 Iron 200 µg/l 37 Manganese 50 µg/l 38 Odour Acceptable to consumers and no abnormal change
39 Oxidisability 5.0 mg/l 02 Note 3 40 Sulphate 250 mg/l Note 1 41 Sodium 200 mg/l 42 Taste Acceptable to consumers and no abnormal change 43 Colony count 220 No abnormal change 44 Coliform bacteria 0 number/100 ml 45 Total organic carbon (TOC) No abnormal Note 4 change 46 Turbidity Acceptable to Note 5 consumers and no abnormal change
RADIOACTIVITY Parameter Parameter Unit Comments value 47 Tritium 100 Bq/l Notes 6 and 8 48 Total indicative dose 0.10 mSv/year Notes 7 and 8
118 Quality of Drinking Water in Ireland A Report For The Year 2001
Notes
Note 1: The water should not be aggressive Note 2: This parameter need not be measured unless the water originates from or is influenced by surface water. In the event of non-compliance with this parametric value, the supply shall be investigated to ensure that there is no potential danger to human health arising from the presence of pathogenic micro- organisms, e.g. cryptosporidium. Note 3: This parameter need not be measured if the parameter TOC is analysed. Note 4: This parameter need not be measured for supplies of less than 10 000m3 a day. Note 5: In the case of surface water treatment, a parametric value not exceeding 1.0 NTU (nephelometric turbidity units) in the water ex treatment works must be strived for. Note 6: Monitoring frequencies to be set at a later date in Part 2 of the Schedule. Note 7: Excluding tritium, potassium Ð40, radon and radon decay products; monitoring frequencies, monitoring methods and the most relevant locations for monitoring points to be set at a later date in Part 2 of the Schedule. Note 8: A. The proposals required by Note 6 on monitoring frequencies, and Note 7 on monitoring frequencies, monitoring methods and the most relevant locations for monitoring points in Part 2 of the Schedule shall be adopted in accordance with the Committee procedure laid down in Article 12 of Council Directive 98/83/EEC. B. Drinking water need not be monitored for tritium or radioactivity to establish total indicative dose where, on the basis of other monitoring carried out, the levels of tritium of the calculated total indicative dose are well below the parametric value.
Part 2 MONITORING TABLE A
PARAMETERS TO BE ANALYSED 1. Check monitoring
The purpose of check monitoring is regularly to provide information on the organoleptic and microbiological quality of the water supplied for human consumption as well as information on the effectiveness of drinking-water treatment (particularly of disinfection) where it is used, in order to determine whether or not water intended for human consumption complies with the relevant parametric values laid down in Part I of this Schedule.
The following parameters must be subject to check monitoring:
Aluminium (Note 1) Ammonium Colour Conductivity Clostridium perfringens (including spores)(Note 2) Escherichia coli (E. coli) Hydrogen ion concentration Iron (Note 1) Nitrite (Note 3)
119 Quality of Drinking Water in Ireland A Report For The Year 2001
Odour Taste Coliform bacteria Turbidity
Notes
Note 1: Necessary only when used as flocculant (*). Note 2: Necessary only if the water originates from or is influenced by surface water (*). Note 3: Necessary only when chloramination is used as a disinfectant (*). (*) In all other cases, the parameters are in the list for audit monitoring.
2. Audit monitoring
The purpose of audit monitoring is to provide the information necessary to determine whether or not all the parametric values specified in Part I of this Schedule are being complied with. All such parameters must be subject to audit monitoring unless it can be established by a sanitary authority, for a period of time to be determined by it, that a parameter is not likely to be present in a given supply in concentrations which could lead to the risk of a breach of the relevant parametric value. This paragraph does not apply to the parameters for radioactivity, which, subject to Notes 6, 7 and 8 in Table C in Part 1 of the Schedule will be monitored in accordance with monitoring requirements adopted under the Committee procedure set out in Article 12 of Council Directive 98/83/EC.
TABLE B
Minimum frequency of sampling and analyses for water intended for human consumption supplied from a distribution network or from a tanker or used in a food-production undertaking
Samples must be taken at the points of compliance as defined in Article 6 to ensure that water intended for human consumption meets the requirements of these Regulations. However, in the case of a distribution network, samples may be taken within the supply zone or at the treatment works for particular parameters if it can be demonstrated that there would be no adverse change to the measured value of the parameters concerned.
120 Quality of Drinking Water in Ireland A Report For The Year 2001
Volume of water distributed Check monitoring Ð number of Audit monitoring Ð number or produced each day samples per year Of samples per year within a supply zone (Notes 3, 4 and 5) (Notes 3 and 5) (Notes 1 and 2) m3 ≥10 ≤100 2 Note 6 > 100 ≤1000 4 1 > 1000 ≤10 000 4 1 + 3 for each 1 000 m3/d + 1 for each 3 300 m3/d and and part thereof of the total part thereof of the total volume volume > 10 000 ≤100 000 3 + 1 for each 10 000 m3/d and part thereof of the total volume > 100 000 10 + 1 for each 25 000 m3/d and part thereof the total volume
Notes
Note 1: A supply zone is a geographically defined area within which water intended for human consumption comes from one or more sources and water quality may be considered as being approximately uniform. Note 2: The volumes are calculated as averages taken over a calendar year. The number of inhabitants in a supply zone may be used instead of the volume of water to determine the minimum frequency, assuming a water consumption of 200 l/day/capita. Note 3: In the event of intermittent short-term supply the monitoring frequency of water distributed by tankers is to be decided by the sanitary authority concerned. Note 4: Where the values of the results obtained from samples taken during the preceding two years are constant and are significantly better than the values specified in Part 1 of the Schedule, and no factor is likely to cause deterioration in the quality of the water, the number of samples specified in Table B of Part 2 of the Schedule and the reduction shall not (except in the case of a supply where the volume of water distributed or produced each day within a supply zone does not exceed 100m3) be more than 50%. Note 5: As far as possible, the number of samples should be distributed equally in time and location. Note 6: To be determined by sanitary authority.
121 USER COMMENT FORM
NOTE: Completed comments to be forwarded to: The Environmental Management and Planning Division, Environmental Protection Agency, P.O. Box 3000, Johnstown Castle Estate, Wexford.
Document Title: The Quality of Drinking Water in Ireland: A Report for the Year 2001.
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DATE ...... PHONE ...... ……FAX...... An Ghníomhaireacht um Chaomhnú Comhshaoil
Bunú Achtaíodh an tAcht fán nGníomhaireacht um - clár hidriméadach náisiúnta a ullmhú agus Chaomhnú Comhshaoil ar an 23ú lá a chur i ngníomh chun faisnéis maidir le d’Aibreán, 1992 agus faoin reachtaíocht seo leibhéil, toirteanna agus sruthanna uisce in bunaíodh an Ghníomhaireacht go hoifigiúil ar aibhneacha, i lochanna agus i screamhuiscí an 26ú lá d’lúil, 1993. a bhailiú, a anailisiú agus a fhoilsiú; agus - maoirseacht i gcoitinne a dhéanamh ar Cúraimí chomhlíonadh a bhfeidhmeanna reachtúla Tá réimse leathan de dhualgais reachtúla ar caomhnaithe comhshaoil ag údarás áitiúla. an nGníomhaireacht agus de chumhachtaí reachtúla aici faoin Acht. Tá na nithe seo a Stádas leanas san áireamh i bpríomhfhreagrachtaí na Is eagras poiblí neamhspleách í an Gníomhaireachta: Ghníomhaireacht. Is í an Roinn Comhshaoil agus Rialtais Áitiúil an coimirceoir rialtais atá - ceadúnú agus rialáil próiseas mór/ilchasta aici. Cinntítear a neamhspleáchas trí na tionsclaíoch agus próiseas eile a modhanna a úsaidtear chun an tArd-Stiúrthóir d’fhéadfadh a bheith an-truaillitheach, ar agus na Stiúrthóirí a roghnú, agus tríd an bhonn rialú comhtháite ar thruailliú tsaoirse a dhearbhaionn an reachtaíocht di (Integrated Pollution Control-IPC) agus cur gníomhú ar a conlán féin. Tá freagracht chun feidhme na dteicneolaíochtaí is fearr dhíreach faoin reachtaíocht aici as réimse atá ar fáil chun na críche sin; leathan feidhmeannas agus cuireann sé seo - faireachán a dhéanamh ar cháiliocht taca breise lena neamhspleáchas. Faoin comhshaoil, lena n-áiritear bunachair reachtaíocht, is coir é iarracht a dhéanamh sonraí a chur ar bun a mbeidh rochtain ag dul i gcion go míchuí ar an nGníomhaireacht an bpobal orthu, agus foilsiú tuarascálacha nó ar aon duine atá ag gníomhú thar a ceann. treimhsiúla ar staid an chomhshaoil; - comhairle a chur ar údaráis phoiblí maidir Eagrú Tá ceanncheathrú na Gníornhaireachta le feidhmeanna comhshaoil agus cuidiú le lonnaithe i Loch Garman agus tá cúig húdaráis áitiúla a bhfeidhmeannas fhoireann chigireachta aici, atá lonnaithe i caomhnaithe a chomhlíonadh; mBaile Átha Cliath, Corcaigh, Cill Chainnigh, - cleachtais atá fónta ó thaobh an Caisleán an Bharraigh agus Muineachán. chomhshaoil de a chur chun cinn, mar shampla, trí úsáid iniúchtaí comhshaoil a Bainistíocht spreagadh, cuspóirí cáilíochta comhshaoil a Riarann Bord Feidhmiúcháin lánaimseartha an leagan síos agus cóid chleachtais a eisiúint Ghníomhaireacht. Tá Ard-Stiúrthóir agus maidir le nithe a théann i bhfeidhm ar an ceathrar Stiúrthóirí ar an mBord. Ceapann an gcomhshaol; Rialtas an Bord Feidhmi úcháin de réir - taighde comhshaoil a chur chun cinn agus mionrialacha atá leagtha síos san Acht. a chomhordú; - gach gníomhaíocht thábhachtach Coiste Comhairleach diúscartha agus aisghabhála dramhaíola, Tugann Coiste Comhairleach ar a bhfuil lena n-áirítear líontaí talún, a cheadúnú dáréag ball cunamh don Ghníomhaireacht. agus a rialáil agus plean náisiúnta Ceapann an tAire Comhshaoil agus Rialtais bainistíochta um dhramháil ghuaiseach, a Áitiúil na baill agus roghnaítear iad, den chuid bheidh le cur i ngníomh ag comhlachtaí is mó, ó dhaoine a ainmníonn eagraíochtaí a eile, a ullmhú agus a thabhairt cothrom le bhfuil suim acu i gcúrsaí comhshaoil nó dáta go tréimhsiúil; forbartha. Tá réimse fairsing feidhmeannas - córas a fheidhmiú a chuirfidh ar ár gcumas comhairleach ag an gCoiste faoin Acht, i leith astúcháin COS (Comhdhúiligh Orgánacha na Gníomhaireachta agus i leith an Aire Sho-ghalaithe) a rialú de bharr cáinníochtaí araon. suntasacha peitril a bheith á stóráil i dteirminéil; - na rialúcháin OMG (Orgánaigh a Mionathraíodh go Géiniteach) a fheidhmiú agus a ghníomhú maidir le húseaid shrianta a leithéad seo d’orgánaigh agus iad a scaoileadh d’aon turas isteach sa timpeallacht; Printed on 100% chlorine free recycled paper