FinalReport Study into the formation of disinfection by-products of chloramination, potential health implications and techniques for minimisation i ii STUDY INTO THE FORMATION OF DISINFECTION BY- PRODUCTS OF CHLORAMINATION, POTENTIAL HEALTH IMPLICATIONS AND TECHNIQUES FOR MINIMISATION FINAL REPORT iii iv STUDY INTO THE FORMATION OF DISINFECTION BY-PRODUCTS OF CHLORAMINATION, POTENTIAL HEALTH IMPLICATIONS AND TECHNIQUES FOR MINIMISATION Prepared by: Simon A Parsons and Emma H. Goslan Centre for Water Science Cranfield University, Cranfield, Bedfordshire, MK43 0AL United Kingdom Sophie A. Rocks, Philip Holmes, and Leonard S. Levy Institute of Environment and Health Cranfield University, Cranfield, Bedfordshire, MK43 0AL United Kingdom and Stuart Krasner La Verne, California United States v DISCLAIMER The contents of this document are subject to copyright and all rights are reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted, in any form or by any means electronic, mechanical, photocopying, recording or otherwise, without the prior written consent of the copyright owner. FINAL REPORT i CONTENTS LIST OF TABLES....................................................................................................................... III LIST OF FIGURES..................................................................................................................... IV ACKNOWLEDGEMENTS ......................................................................................................... VI EXECUTIVE SUMMARY........................................................................................................... VII Acronyms and abbreviations ................................................................................................... xi 1 INTRODUCTION....................................................................................................................1 1.1 Objectives.............................................................................................................1 1.2 Background ..........................................................................................................1 2 METHODOLOGY...................................................................................................................4 2.1 Selection of DBPs for survey................................................................................4 2.2 Methods................................................................................................................8 2.2.1 Water Characterisation.................................................................................8 2.2.2 Chlorine Demand and Formation Potential Tests.......................................9 2.2.3 Disinfection By-Product Analysis.................................................................9 3 SAMPLING SURVEY ...........................................................................................................10 3.1 Selection of treatment works..............................................................................10 3.1.1 Final and distribution samples overview ...................................................11 3.1.2 Final and distribution samples DBPs ........................................................12 3.1.3 Summary ....................................................................................................21 3.2 In-works samples................................................................................................22 3.2.1 Formation potential data............................................................................24 3.2.2 Correlation with water quality data. ...........................................................28 3.2.3 Removal of DBP precursors. .....................................................................32 3.2.4 Summary ....................................................................................................35 4 REVIEW OF TOXICOLOGY AND AESTHETIC DATA AND ASSESSMENT OF RISK ........37 4.1 BACKGROUND.........................................................................................................37 4.2 HAZARD PROFILES FOR DBPs.........................................................................38 4.2.1 Literature search.........................................................................................38 4.2.2 Derivation of hazard profiles and acceptable exposures .........................38 4.2.3 Risk assessment ........................................................................................39 4.3 OVERALL ASSESSMENT OF HAZARD PROFILES AND KEY DETERMINANTS OF TOXICITY FOR CHEMCIALS DETECTED IN EXPERIMENTAL INVESTIGATIONS .40 4.3.1 Chemicals not detected in water samples................................................40 4.3.2 Chemicals detected in water samples ......................................................41 4.3.3 Consideration of risk for individual or groups of compounds for which the predicted daily intake from drinking water amounted to less than 5% of the reference standard......................................................................................................43 4.3.4 Consideration of risk for individual or groups of compounds for which the predicted daily intake from drinking water amounted to between 5 and 10% of the reference standard......................................................................................................44 4.3.5 Consideration of extent of risk for compounds or groups for which predicted daily intake from drinking water amounted to 10% or greater of the reference standard......................................................................................................45 4.3.6 Consideration of potential for mixture interactions influencing overall toxic outcome 47 i 4.4 CONCLUSIONS AND RECOMMENDATIONS...................................................48 5 OVERALL CONCLUSIONS .................................................................................................49 6 REFERENCES .....................................................................................................................50 APPENDIX A METHOD STATEMENTS...................................................................................54 A.1 Method Statements ..................................................................................................54 A.1.1 Non purgeable organic carbon (NPOC) measurement by high-temperature combustion method....................................................................................................54 A.1.2 pH ......................................................................................................................55 A.1.3 Iodide and Bromide...........................................................................................56 A.1.4 Conductivity (Standard Method 2510 A, APHA 1998) .....................................57 A.1.5 High performance size exclusion chromatography (HPSEC)..........................58 A.1.6 Chlorine/chloramine demand (Standard Method 2350 B, APHA 1998)..........59 A.1.7 Formation potential test (adapted from procedure 5710 in ‘Standard Methods for the Examination of Water and Wastewater’ (American Public Health Association 1992)). .........................................................................................................................61 A.1.8 Determination of Haloacetic acids (HAA) in drinking water (adapted from USEPA Method 552.3)................................................................................................62 A.1.9 Trihalomethanes (THMs), Haloacetonitriles (HANs) and Halonitromethanes (HNMs) (adapted from USEPA Method 551.1)..........................................................64 A.1.10 Analysis of Nitrosamines (USEPA method 521).............................................67 A.1.10 Analysis of Cyanogen Chloride and Cyanogen Bromide (adapted from Sclimenti et al. 1996)...................................................................................................68 A.2 Method Limits of Detection and Minimum Reporting Limits (MRL)........................70 A.3 Precision and Bias in fortified sample matrices.......................................................72 APPENDIX B RESULTS OF SURVEYS AND LABORATORY TESTS......................................77 APPENDIX C TASK 3 REPORT............................................................................................. 121 ii LIST OF TABLES Table 1-1. International guidelines or regulations for disinfection by-products (adapted from WHO, 2006)..............................................................................................2 Table 2-1. Summary of DBP levels found in recent major surveys and chloramination studies. .............................................................................................................5 Table 2-2 DBPs selected for occurrence survey .............................................................8 Table 3-1. Summary of treatment and disinfection at surveyed works..........................10 Table 3-2. Concentration of selected DBPs and their precursors .................................11 Table 3-3. Water quality data at works surveyed – Winter..............................................22 Table 3-4. Water quality data at works surveyed – spring..............................................23 Table 3-5. Water quality data at works surveyed – summer ..........................................23 Table 3-6. Correlation Table – In-works