Pesticide Degradates of Concern to the Drinking Water Community

Project #2938 Subject Area: High-Quality Water

Web Report

TO: Awwa Research Foundation Subscribers

RE: Enclosed report, Pesticide Degradates of Concern to the Drinking Water Community

The objectives of this project were to develop a priority list of pesticides and their degradates and adjuvants of potential concern and identify related research priorities. To meet these objectives, the research team collated data on the occurrence, properties, persistence and toxicity of pesticide degradates and adjuvants in soils, waters, and treatment processes; and held a workshop to discuss prioritization approaches and research needs. The information generated from the literature review and workshop recommendations has been summarized in the enclosed report and was used to develop a priority list of pesticide degradates. General research needs in four key areas were also identified at the workshop and are included in the report.

Due to the technical nature of this project, the results are being made available to both subscribers and the research community through this electronic version of the report on AwwaRF’s web site.

The Awwa Research Foundation (AwwaRF) is a member-supported, international, nonprofit organization that sponsors research to enable water utilities, public health agencies, and other professionals to provide safe and affordable drinking water to consumers.

The Foundation’s mission is to advance the science of water to improve the quality of life. To achieve this mission, the Foundation sponsors studies on all aspects of drinking water, including supply and resources, treatment, monitoring and analysis, distribution, management, and health effects. Funding for research is provided primarily by subscription payments from approximately 1,000 utilities, consulting firms, and manufacturers in North America and abroad. Additional funding comes from collaborative partnerships with other national and international organizations, allowing for resources to be leveraged, expertise to be shared, and broad-based knowledge to be developed and disseminated. Government funding serves as a third source of research dollars.

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More information about the Foundation and how to become a subscriber is available on the Web at www.awwarf.org.

Prepared by: Simon A Parsons School of Water Sciences Cranfield University, Cranfield, Bedfordshire, MK43 OAL, United Kingdom and Alistair Boxall, Chris Sinclair, and Carmel Ramwell University of York Central Science Laboratory, Sand Hutton, York, YO41 1LZ, United Kingdom

Sponsored by: Awwa Research Foundation 6666 West Quincy Avenue, Denver, CO 80235-3098

Published by:

This study was funded by the Awwa Research Foundation (AwwaRF). AwwaRF assumes no responsibility for the content of the research study reported in this publication or for the opinions or statements of fact expressed in the report. The mention of trade names for commercial products does not represent or imply the approval or endorsement of AwwaRF. This report is presented solely for informational purposes.

LIST OF TABLES...... ix

LIST OF FIGURES ...... xi

FOREWORD…...... xiii

ACKNOWLEDGMENTS ...... xv

EXECUTIVE SUMMARY ...... xvii

CHAPTER 1: INTRODUCTION AND OBJECTIVES...... 1

CHAPTER 2: USAGE OF PESTICIDES AND ADJUVANTS ...... 5 Introduction...... 5 Uses of pesticides...... 5 Agricultural and horticultural use ...... 6 Industry/commercial/government markets ...... 7 Household usage ...... 8 Pesticides used in or near water...... 9 Adjuvants and co-formulants...... 9

CHAPTER 3: DEGRADATES IN THE ENVIRONMENT ...... 13 Introduction...... 13 Formation in the environment...... 14 Methods for determining transformation routes ...... 19 Experimental methods ...... 19 Predictive approaches ...... 19 Characteristics of degradates of major pestcides...... 20 Fate of degradates in the environment...... 24 Degradation in the environment...... 24 Routes into environmental waters...... 26 Non-agricultural...... 26 Effects of climate and season...... 27 Mobility in the environment ...... 27 Occurrence in the environment...... 29 Soil ...... 34 Surface water ...... 34 Groundwater ...... 35 Occurrence In Drinking water Supplies and Fate during Drinking water treatment ...36 Drinking water standards ...... 38

CHAPTER 4: PRIORITISATION OF DEGRADATES...... 39 Introduction...... 39 Prioritization approach...... 39

©2008 AwwaRF. ALL RIGHTS RESERVED Data selection...... 39 Exposure ...... 39 Risk characterization and ranking...... 40 Calculation of exposure index ...... 40 Amount of degradate formed...... 40 Sorption...... 41 Persistence...... 41 Effects ...... 42 Prioritisation of pesticides in use in the USA and UK...... 42 USA - Agricultural Pesticides...... 42 USA - Home and Garden Use Pesticides...... 45 USA - Industrial/Commercial/Government Use Pesticides...... 45 UK...... 47 Sample calculation of the risk index...... 49 Use and limitations of the prioritization scheme ...... 50

CHAPTER 5: CONCLUSIONS AND FUTURE RESEARCH ...... 51 Conclusions...... 51 Future research...... 51

CHAPTER 6: RELEVANCE FOR UTILITIES ...... 53

APPENDIX 1: THE EXTENT OF PESTICIDE DEGRADATE FORMATION IN THE ENVIRONMENT ...... 55

APPENDIX 2: THE DEGRADATION RATE OF PESTICIDE DEGRADATES IN THE ENVIRONMENT ...... 71

APPENDIX 3 : DEGRADATE ORGANIC CARBON PARTITION COEFFICIENT (KOC) ...... 75

APPENDIX 4: THE OCCURRENCE OF PESTICIDE DEGRADATES IN THE ENVIRONMENT ...... 79

APPENDIX 5: ADI FOR PESTICIDES ...... 89

APPENDIX 6: MAMMALIAN ACUTE, SUBACUTE AND SUBCHRONIC DATA FOR PESTICIDE DEGRADATES...... 91

APPENDIX 7: DEGRADATE ABBREVIATIONS USED IN THE DATA APPENDICES ...... 93

APPENDIX 8: THE RISK INDEX AND DATA AVAILABILITY FOR DEGRADATES FROM THE US MOST USED AGRICULTURAL PESTICIDES ....95

REFERENCES ...... 103

LIST OF ABBREVIATIONS...... 117

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1.1 Workshop Participants List...... 3

2.1 Most commonly used conventional pesticides in agriculture in the USA in 1999...... 7

2.2 Most commonly used pesticides in the industry/commercial/government sector in the US and approved substance in the UK for amenity use...... 8

2.3 Most commonly used pesticides in the US households in 1999...... 8

2.4 Top 10 adjuvants used in the UK (excluding co-formulants)...... 10

3.1 Examples of biodegradation reactions that are relevant to pesticides ...... 15

3.2 Pesticide degradates identified as formed at ≥ 10% of the applied pesticide in one or more degradation studies ...... 22

3.3 Summary table containing the organic carbon partition coefficient (Koc) for pesticide degradates ...... 29

3.4 A summary of pesticide degradate environmental occurrence data ...... 31

3.5 Drinking water standards set for pesticide degradates...... 38

4.1 The risk index for degradates from the US most used agricultural pesticides risk index is >0.5...... 44

4.2 The risk index and data availability for degradates from the US most used home and garden use pesticides...... 45

4.3 The risk index and data availability for degradates from the US most used Industrial/Commercial/Government use pesticides ...... 47

4.4 The risk index for degradates from the UK most used agricultural pesticides where the risk index is >0.5 ...... 48

2.1 Usage of different pesticide classes in agricultural and non-agricultural market sectors (taken from Donaldson et al. 2002)...... 6

2.2 Relative areas of crops treated with pesticides annually in the UK (data taken from Thomas and Wardman 1999)...... 6

3.1 Degradation of the triazine herbicides to DIA and DEA (adapted from Scribner et al. 2000)...... 15

3.2 The transformation and cleavage degradation pathways of chloroacetamide (e.g., alachlor) and sulfonylurea (e.g., imazosulfuron) herbicides...... 16

3.3 The oxidative desulphurisation of the insecticide chlorpyrifos ...... 17

3.4 Selected degradation pathways for the insecticide carbaryl (Boxall et al. 2004a)...... 18

3.5 Formation of pesticide degradates as a percentage of the parent pesticide (each degradate is represented by the degradation study where it was most prevalent)...... 20

3.6 The degradation of pesticide degradates, classified according to the Soil Survey and Land Research Centre (SSLRC) persistence classification...... 25

3.7 The comparative persistence of pesticides and their degradates in various environmental media...... 26

3.8 The comparative sorption of pesticide degradates and their parent pesticides...... 28

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The Awwa Research Foundation is a nonprofit corporation that is dedicated to the implementation of a research effort to help utilities respond to regulatory requirements and traditional high-priority concerns of the industry. The research agenda is developed through a process of consultation with subscribers and drinking water working professionals. Under the umbrella of a Strategic Research Plan, the Research Advisory Council prioritizes the suggested projects based upon current and future needs, applicability, and past work; the recommendations are forwarded to the Board of Trustees for final selection. The foundation also sponsors research projects through the unsolicited proposal process; the Collaborative Research, Research Applications, and Tailored Collaboration programs; and various joint research efforts with organizations such as the U.S. Environmental Protection Agency, the U.S. Bureau of Reclamation, and the Association of California Water Agencies. This publication is a result of one of these sponsored studies, and it is hoped that its findings will be applied in communities throughout the world. The following report serves not only as a means of communicating the results of the water industry’s centralized research program, but also as a tool to enlist the further support of the nonmember utilities and individuals. Projects are managed closely from their inception to the final report by the foundation’s staff and large cadre of volunteers who willingly contribute their time and expertise. The foundation serves a planning and management function and awards contracts to other institutions such as water utilities, universities, and engineering firms. The funding for this research effort comes primarily from the Subscription Program, through which water utilities subscribe to the research program and make an annual payment proportionate to the volume of water they deliver and consultants and manufacturers subscribe based on their annual billings. The program offers a cost-effective and fair method for funding research in the public interest. A broad spectrum of water supply issues is addressed by the foundation’s research agenda: resources, treatment and operations, distribution and storage, water quality and analysis, toxicology, economics, and management. The ultimate purpose of the coordinated effort is to assist water suppliers to provide the highest possible quality of water economically and reliably. The true benefits are realized when the results are implemented at the utility level. The foundation’s trustees are pleased to offer this publication as a contribution toward that end.

David E. Rager Robert C. Renner, P.E. Chair, Board of Trustees Executive Director Awwa Research Foundation Awwa Research Foundation

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The authors wish to thank Awwa Research Foundation (AwwaRF) for funding this project and Alice Fulmer for her excellent support as project manager. The authors would like to thank the following people and organizations for their cooperation, participation and support of this project.

• The technical advisors to the project Dana Kolpin (USGS), Kathrin Fenner (EAWAG), Steve Maund (Syngenta) and Andrew Craven (Pesticides Safety Directorate) for their efforts in reviewing the draft prioritization scheme and helping to run the symposium and workshop. • Noirin Casey, Andrew Spears and Keith Robertson of the International Water Association for help in organizing the symposium and workshop in Prague. • Michelle Everitt for administrative support and workshop organization.

The authors would also like to thank all the symposium and workshop delegates for their contribution including the Project Advisory Committee members Dan Binder and Roderick Dunn, City of Columbus Department of Water, Richard Gullick, American Water, Kathy Kuivila, USGS and Joel Pedersen, University of Wisconsin-Madison.

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BACKGROUND

Recent U.S. and European monitoring data has shown detectable concentrations of pesticides in more than 95 percent of sampled surface waters and approximately 50 percent of sampled groundwaters, making them of concern to the drinking water industry. Pesticides can participate in a variety of transformation processes, resulting in degradation products that may accumulate in the environment. As the number of degradates and adjuvants is extremely large, a need was identified for list of pesticides, degradates, and adjuvants that are of potential concern to the drinking water community and that should be considered in environmental surveillance monitoring programs.

RESEARCH OBJECTIVES

The objectives of this project were to: 1. Develop a list of pesticides, degradates and adjuvants of potential concern. 2. Collate data on the occurrence, properties, persistence and toxicity of the degradates and adjuvants in soils, waters and treatment processes; and 3. Develop and run a workshop to discuss approaches to prioritization approaches and research needs; and 4. Using the information, generated in 1 to 3 and the recommendations from the workshop, develop a priority list of degradates.

APPROACH

To meet the project objectives, a workshop was convened and attended by 33 experts from academia, consultancies, government bodies, research associations and water utilities. The workshop was held in Prague, Czech Republic on June 4-6th, 2004 and included a pre- workshop symposium designed to update each participant with current knowledge in analysis, fate and treatability of pesticides, degradates and adjuvants. The workshop lead to the project focusing primarily on pesticide degradates.

PESTICIDE USAGE

A literature review provided an overview of the available information on the usage amount and pattern for pesticide products as these will be key factors in determining the amount of a substance that will enter the environment. Data are available on the amounts of different pesticide active ingredients used in the US and the UK and indicates that the greatest use of pesticides is in agriculture, however large amounts are also used in the industrial/commercial/government and home and garden areas. The data was used to rank pesticide and adjuvant products and this indicated that herbicidal products are used in the highest amounts with the major active substance being atrazine, glyphosate, acetochlor and 2,4-D. The highest usage insecticides were malathion, chlorpyrifos and tebufos and the highest used fungicides were chlorothalonil and mancozeb.

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Once released into the environment, pesticides are susceptible to degradation by biotic and abiotic means. Pesticide transformation can produce a diverse range of compounds, and it is important that degradates are considered when determining the risks to the environment and human health posed by the application of a pesticide. Here, information from the literature and industry data have been used to identify the nature and amounts of pesticide degradates, and we found that 92 pesticide degradates have been detected in the environment with 29 detected in groundwater and 27 detected in surface waters. Therefore the potential for these compounds to enter water drinking water sources is high. Information is also presented on the occurrence, degradation and sorption in the environment and in water treatment works.

PRIORITIZATION SCHEME

The impact of a degradate on drinking water quality will be determined by its potential to enter drinking water supplies, its treatability and its potential effects on human health. Here a risk-based prioritization scheme has been developed which considers both exposure and effects. The scheme uses a range of factors including the amount of parent pesticide used, the way in which the parent compound is used, the amount of a particular degradate formed, the mobility of the degradate and its persistence to generate a risk score. The prioritization procedure was applied to major pesticides in use in the USA and UK in order to illustrate the prioritization approach and to begin to identify degradates of potential concern to the water industry. Application of the prioritization approach to the degradates indicated that the degradates of alachlor, acetochlor, cyanazine, atrazine, dichloropropene, dicamba and 2-4-D as likely to be of most concern to US water supplies whilst, in the UK, degradates of cyanazine, isoproturon and flufenacet were ranked highest and should be selected first for monitoring and treatability studies

FUTURE RESEARCH

This project identified future research studies that will benefit drinking water utilities and in particular four key areas were identified (i) information management, (ii) analysis, (iii) monitoring and (iv) treatment. Treatment issues included studies into the fate of compounds in conventional and advanced treatment processes and also the likely transformation of compounds during treatment.

RECOMMENDATIONS FOR DRINKING WATER UTILITIES

The workshop participants recognized and strongly endorsed the importance of drinking water utility participation in the development of a usable and robust prioritization scheme. The identified needs were grouped into six major priorities and will help extend the usefulness of the prioritization scheme and our overall knowledge on the analysis, occurrence and fate of pesticide degradates.

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The availability of a reliable supply of water is one of the most important determinants of our health. Historically improvements in our health have been related to improvements in our water supply system from source to tap. In both the US and the EU, drinking water from community and non-community water systems is regulated for the protection of human health. The quality of water we receive today is achieved through improvements in source protection, water treatment, operation and maintenance, water quality monitoring, and training and education. Recent U.S. and European monitoring data has shown detectable concentrations of pesticides in more than 95 percent of sampled surface waters and approximately 50 percent of sampled groundwaters, making them of concern to the drinking water industry. Pesticides can participate in a variety of transformation processes, resulting in degradation products that may accumulate in the environment. Moreover, many pesticide products and formulations contain compounds labeled as inerts by the United States Environmental Protection Agency (USEPA) that may be of toxicological concern. These inert ingredients, or adjuvants, can also contaminate water supplies. The general focus of this report is pesticide degradates rather than the parent compunds or adjuvants. Adjuvants were initially considered in the project but the general consensus of the expert workshop was to focus on the pesticide degradates. For regulation purposes pesticides and related products are defined as any organic insecticide, herbicide, fungicide, nematocide, acaricide, algicide, rodenticide, slimicide and any product related to any of these including any growth regulator, and their relevant metabolites, degradation and reaction products. In the US, the EPA has established maximum contaminant level goals for drinking water resources and maximum contaminant levels for 83 contaminants, including 24 pesticides. While limits have been set in the US (MCLs range from 500 μg/L for Picloram down to 0.2 μg/L for Lindane) and in the UK (standards for pesticides and related products include 0.03 µg/L for aldrin, dieldrin, heptachlor and heptachlor epoxide, 0.10 µg/L for other pesticides and a total pesticides limit of 0.50 µg/L), little guidance has yet been issued on pesticide degradates. For example, in the UK, the Drinking Water Inspectorate (DWI) has stated that there is no evidence at the present time that any pesticide metabolites, degradation or reaction products represent a risk to health and therefore no additional monitoring is required. However, the current data are very limited so it would seem wise to begin to consider degradates and adjuvants in more detail to ensure that they are not posing a risk to human health. As the number of degradates and adjuvants is extremely large, there is an urgent need to prioritize substances so that monitoring and research work can focus on substances that are most likely to be of concern. Thus, there is a need to develop a comprehensive list of pesticides, degradates, and adjuvants that are of potential concern to the drinking water community and that should be considered in environmental surveillance monitoring programs. This report describes the results of a 12-month long AwwaRF funded project, the overall aim of which was to develop a list of priority substances of potential concern in drinking water supplies. The objectives were to:

1. Develop a list of pesticides, degradates and adjuvants of potential concern (Chapter 2). 2. Collate data on the occurrence, properties, persistence and toxicity of the degradates and adjuvants in soils, waters and treatment processes (Chapter 3); and

©2008 AwwaRF. ALL RIGHTS RESERVED 3. Develop and run a workshop to discuss approaches to prioritization approaches and research needs; and 4. Using the information, generated in 1 to 3 and the recommendations from the workshop, develop a priority list of degradates and where possible adjuvants (Chapter 4).

To meet the project objectives, a workshop was convened and attended by 33 experts from academia, consultants, government bodies, research associations, and water utilities. Workshop participants were chosen based not only on their expertise and experience but also on their willingness and availability to participate in the workshop. Based on inputs from the AwwaRF project manager and recommendations by the project team and technical advisors, a list of workshop invitees was established. The workshop was held in Prague, Czech Republic on June 4-6th, 2004 and included a pre-workshop symposium designed to update each participant with current knowledge in analysis, fate and treatability of pesticides, degradates and adjuvants.

Table 1.1 Workshop Participants List

Name Organization Country Craig Adams University of Missouri-Rolla USA Alistair Boxall University of York UK Andrew Craven Pesticides Safety Directorate UK Kathrin Fenner EAWAG Switzerland Michael Fry Stratus Consulting USA Alice Fulmer AwwaRF USA Richard Gullick American Water USA Bent Halling-Sorensen Royal Danish School of Pharmacy Denmark Michelle Hladik John Hopkins University USA Anthony Johnson Lhasa Ltd, University of Leeds UK Dana Kolpin US Geological Survey USA Rai Kookana CSIRO Australia Kathy Kuivila US Geological Survey USA The Jan Linders RIVM Netherlands Steve Maund Syngenta Switzerland Michael Meyer US Geological Survey USA Christoph Neumann Syngenta Switzerland Thuy Nguyen US EPA USA Simon Parsons Cranfield University UK Joel Pedersen University of Wisconsin-Madison USA Nick Poletika Dow Agroscience LLC USA The Leo Puijker KIWA Netherlands Kees Romijn Bayer CropScience GmbH Germany Hans Siegrist EAWAG Switzerland Geoff Siemering San Francisco Estuary Institute USA Chris Sinclair University of York UK Shane Snyder Southern Nevada Water Authority USA Dennis Tierney Syngenta Crop Protection Inc. USA Jack Wang Louisville Water USA Derek Wilson Yorkshire Water UK

INTRODUCTION

Pesticidal products play an important role in modern agriculture and typically comprise a formulation containing the active ingredient and co-formulants. Other substances may be added during the pesticide application process in order to increase the efficacy of the product. Following release to the environment both the active ingredient and the co-formulants may be degraded by abiotic and biotic processes resulting in the formation of degradates. The environment may therefore be exposed to a mixture of the parent compound, degradates and co- formulants. In this Chapter we provide an overview of the available information on the use of pesticides and adjuvants.

USES OF PESTICIDES

The usage amount and pattern for a pesticide product will be a key factor in determining the amount of a substance that will enter the environment. A product can be used in a number of ways, including to treat arable crops, fruit crops, in greenhouses, in amenity areas, golf courses and in the home. In the UK and US, data are available on the amounts of different pesticide active ingredients used (Donaldson et al. 2002; Garthwaite et al. 1997). For example, data from the US indicate that the greatest use of pesticides is in agriculture, however large amounts are also used in the industrial/commercial/government and home and garden areas (Figure 2.1). The specific active substances used will vary depending on the usage scenario. In the following sections we describe the major substances used, based on detailed data for the UK and the US.

300000

250000 home and garden industry/commercial/government 200000 agriculture

150000 u s e d ( t o n )

100000 A m o u nt 50000

0 herbicides and insecticides fungicides nematicide other plant grow th and miticides and fumigant regulators Pesticide type

Figure 2.1 Usage of different pesticide classes in agricultural and non-agricultural market sectors (taken from Donaldson et al. 2002).

Agricultural and horticultural use

Detailed data are available on the active substances used in agriculture in the UK and the US (e.g., Donaldson et al. 2002; Garthwaite et al.1997, 1999a and b, 2002). In the UK, the greatest amounts of pesticides are used in arable farming and treatment of grassland and fodder (Figure 2.2).

arable

grassland and fodder

vegetables

orchards

other

Figure 2.2 Relative areas of crops treated with pesticides annually in the UK (data taken from Thomas and Wardman 1999)

In terms of weight of substances applied to arable land in the UK in 2002, herbicides and desiccants were used in the largest amounts (71%) followed by fungicides (12%), growth regulators (11%), insecticides and nematicides (2%), molluscicides (1%) and seed treatments

©2008 AwwaRF. ALL RIGHTS RESERVED (1%). The most extensively used herbicides were glyphosate, isoproturon, fluroxypyr, mecoprop- P and diflufenicam. The most used fungicides were epoxiconazole, azoxystrobin, tebuconazole, kresoxim methyl, fenpropimorph and trifloxystrobin and the most widely used insecticides were the pyrethroids (cypermethrin, esfenvalerate), orgaophosphates and the carbamates (pirimicarb) (Garthwaite et al. 2002).

Table 2.1 Most commonly used conventional pesticides in agriculture in the USA in 1999 (taken from Donaldson et al. 2002)

Rank Substance Mass a Substance Mass a Rank

1 Atrazine 74 - 80 14 Chloropicrin 8 - 10 2 Glyphosate 67 - 73 15 Copper hydroxide 8 - 10 3 Metam sodium 60 - 64 16 Chlorpyrifos 8 - 10 4 Acetochlor 30 - 35 17 Alachlor 7 - 10 5 Methyl bromide 28 - 33 18 Propanil 7 - 10 6 2,4-D 28 - 33 19 EPTC 7 - 9 7 Malathion 28 - 32 20 Dimethamid 6 - 8 8 Metolachlor 26 - 30 21 Mancozeb 6 - 8 9 Trifluralin 18 - 23 22 Dicamba 6 - 8 10 Pendimethalin 17 - 22 23 Terbufos 5 - 7 11 Dichloropropene 17 - 20 24 Ethephon 5 - 6 12 Metolachlor-s 16 - 19 25 Cyanazine 4 - 8 13 Chlorothalonil 9 - 11

a - ranked by range in millions pounds of active ingredient

Industry/commercial/government markets

Usage in the industry/commercial and government sectors includes the control of weeds on highways and berms and the treatment of park and amenity areas and open spaces. While the amount of active substances used in the industrial/commercial and government areas are significantly lower than those used in agriculture, the use pattern may mean that a disproportionate amount of these substances will reach water bodies compared to the agricultural area. For example, pesticides applied to highways and pavements may be washed off from the hard surface into streams and rivers. The major active substances used in this sector in the US are 2,4-D, glyphosate and pendimethalin (Table 2.2). Data are not available on usage in the UK but a range of active ingredients are approved (Table 2.2).

Table 2.2 Most commonly used pesticides in the industry/commercial/government sector in the US and approved substance in the UK for amenity use (taken from Donaldson et al. 2002 and Whitehead 2004)

US UK Rank Active Mass a Approved active substance substance

1 2,4-D 17 - 20 Dichlorophen 2 Glyphosate 11 - 14 2,4-D 3 Copper sulphate 5 - 7 Dicamba 4 Pendimethalin 3 - 5 Triclopyr 5 Chlorpyrifos 3 - 5 Diuron 6 MSMA 2 - 4 MCPA 7 Chlorothalonil 2 - 4 Paraquat 8 Diuron 2 - 4 Glyphosate 9 Malathion 1 - 3 Sodium chlorate 10 Trichlopyr 1 - 3 Diquat

a - ranked by range in millions pounds of active ingredient

Household usage

Pesticides are commonly used in the home for weed and insect control. While the amounts used are significantly lower than in the agricultural sector, the substances are typically used by non-trained operators, there is therefore a high likelihood that the active substance may be released to water courses (e.g., via pavement drainage systems) or to treatment works due to improper disposal down the drain. In the US in 1999, 2,4-D was the most commonly used herbicide in the home and six of the top ten used substances were herbicides (Table 2.3).

Table 2.3 Most commonly used pesticides in the US households in 1999 (taken from Donaldson et al. 2002)

Rank Substance Mass a Rank Substance Mass a

1 2,4-D 7 - 9 6 Chlorpyrifos 2 - 4 2 Glyphosate 5 - 8 7 Carbaryl 2 - 4 3 MCPP 3 - 5 8 Benefin 1 - 3 4 Dicamba 3 - 5 9 Malathion 1 - 3 5 Diazinon 2 - 4 10 DCPA 1 - 3

a - ranked by range in millions pounds of active ingredient

A number of substances are approved for control of weeds in or near water. Consequently, these substances, even though they may only be used in small amounts, have a high potential to enter water bodies. Substances currently approved in the UK include 2,4-D, dichlobenil, diquat, glyphosate, maleic hydrazide and terbutryn. In the US some active substances are approved for use in aquatic scenarios such as fresh water ponds, lakes reservoirs and drainage canals to control aquatic vegetation (e.g., glyphosate, 2,4-D, diquat, fluridone and imazapyr).

ADJUVANTS AND CO-FORMULANTS

An adjuvant is a compound other than water which is used with a pesticide to enhance its effectiveness. More specifically, a co-formulant is a compound pre-mixed with the technical- grade active ingredient (a.i.) to create a formulated pesticide product, whereas an adjuvant (or tank-mix adjuvant) is a product sold as a single entity that can be mixed with formulated pesticides. Historically, co-formulants have been known as additives or inerts, the latter term being particularly misleading. In this report, unless otherwise stated, the term adjuvant will be used to include co-formulants. Adjuvants can be described as bio-enhancing or utility. Bio-enhancing adjuvants improve the efficacy of the a.i. These can include stickers, spreaders, penetrants and humectants. A utility adjuvant modifies the physical characteristics of the spray solution and includes drift control agents, buffering and acidifying agents, defoamers, colorants and compatibility agents. However, a single adjuvant can have several modes of action thus it is advantageous to group adjuvants by their chemistry, namely surfactants, oils (mineral and vegetable), synthetic latex and inorganic salts. Only limited data are available on the usage of adjuvants, information on the top ten products in the UK is given in Table 2.4. By far the largest chemical group is surfactants which can have multiple desired properties enhancing the spreading, sticking and absorption of pesticides. Within this group non-ionic surfactants are the largest group; others include anionic, cationic and organosilicone.

Adjuvant % Number of products containing adjuvant

Vegetable oil 70 18.5 Alkyl phenol ethoxylate 56 14.8 Fatty amine ethoxylate 48 12.7 Ethoxylate condensates 37 9.8 Paraffinic 27 7.1 Block copolymer 20 5.3 Synthetic latex 19 5.0 Pinolene 17 4.5 Mineral oil 15 4.0 Propionic acid 15 4.0

Surfactants are widely used in other industries and agrochemicals account for only 2% of the global surfactant market compared to detergents and cleaning products (54%) and personal care (11%) (Agriculture and Agri-food Canada, 2002). Due to the abundant use of surfactants there are data available on the fate and occurrence of some of the main surfactant groups including alkyl phenol ethoxylates (APE) (Environment Canada and Health Canada 2000), alkyl amine ethoxylates (AME) (Madsen et al. 2001), alcohol ethoxylates (AE) (Madsen et al. 2001) and linear alkylbenzene sulfonates (LAS) (HERA 2004). When extrapolating the available data on surfactants to the scenario of pesticide use consideration should be given to the specifics. For example, much of the reported work involves the fate of surfactants in wastewater treatment plants (WWTPs). Values given for degradation rates commonly assume a media of sludge or sludge-amended soil which may give rise to a faster rate than in water or untreated soil with fewer microbes. Likewise, water monitoring data tend to be focused around rivers and lakes receiving effluent from WWTPs or textile industries and these concentrations are not necessarily representative of potential surfactant concentrations arising from pesticide use. Nevertheless, the existing data could allow the pesticide use scenario to be put into context, particularly given the fact that for tank-mix adjuvants the rates of use are typically 1% or less volume: volume of pesticide. A shortcoming of the current literature with regard to surfactants in the environment arising from pesticide use is the paucity of data on movement to, and concentrations in groundwater. This is of particular note because a) groundwater receives relatively minimal treatment prior to distribution to consumers and b) degradation in anaerobic conditions can be slow, potentially allowing any pollutants to accumulate. Another limitation of the available data was that reports were not always compound specific but considered a chemical group. For example, with LAS the alkyl chain length can vary, as can its position on the benzene ring, both of which can affect the fate and effect of the compound potentially hampering the development quantitative structure-activity relationships (QSAR) and/or their validation with field data.

©2008 AwwaRF. ALL RIGHTS RESERVED However, in reality, a surfactant will consist of a range of chain lengths thus a generic approach to considering the fate of chemical groups may be more appropriate. There is a general move away from the use of mineral oil to that of vegetable oil for environmental reasons. There is very limited data on the fate of oils used as additives in pesticides. On the global market, the use of oleochemicals for surfactants is less than half that for use in soaps (Agriculture and Agri-food Canada, 2002). Although no figures were found for the use of synthetic latex in pesticides, it is probable that, like surfactants, agrochemicals account for only a small percentage of the global use of latex which includes industries such as the automotive industry, information technology and the household and medical sector. With regard to the use of inorganic salts such as ammonium sulphate as adjuvants, these salts are also fertilizers and the fate of such compounds is widely covered under the umbrella of fertiliser use and/or the fate of nitrates. In addition to the major chemical groups of adjuvants there are numerous other compounds listed as being used as adjuvants or co-formulants, for example those listed by the USEPA (www.epa.gov/opprd001/inerts/lists.html)(e.g. hydroquinone, isophorone, nonylphenol and phthalic acid). Again, many of these compounds have uses in a wide variety of industries, thus it may be difficult to delineate their occurrence in the environment arising from the application of pesticides. To more accurately predict the fate and effects of adjuvants in the environment, data are required on the composition of co-formulants in pesticide products and the use of tank-mix adjuvants to enable total usage data to be calculated. .

INTRODUCTION

Once released into the environment, pesticides are susceptible to degradation by biotic and abiotic means. This can result in the formation of a range of compounds (Roberts, 1998; Roberts and Hutson, 1999). The transformation of a pesticide includes all processes where structural change of the pesticide takes place producing a degradate (Somasundaram and Coats, 1991). Therefore, pesticide transformation can produce a diverse range of compounds and it is important that degradates are considered when determining the risks to the environment and human health posed by the application of a pesticide. However, the risks posed by degradates should not be considered individually but always in conjuction with to those risks posed by their parental pesticides. Once pesticides are applied during agricultural practice there is the potential for degradates to form. These compounds together with the parent pesticide can then, depending on their physico-chemical properties, move from the soil to other environmental media. These compounds can volatilize into the air and move large distances in the particulate or gaseous phase and be deposited by rainfall large distances away from the site of application (Goolsby et al. 1997); (Majewski et al. 1998); (Thurman and Cromwell, 2000). They can move vertically through the soil profile to groundwater and then away from the site of application via aquifer transport (Schiavon, 1988); (Widmer and Spalding, 1995); (Broholm et al. 2001). Additionally, there is also the potential for these compounds to enter surface waters when they travel laterally either via overland runoff due to heavy rainfall or via sub-soil tile drains, entering agricultural ditches and streams and then on to major rivers, reservoirs and ultimately in estuaries and the marine environment (Aga and Thurman, 2001); (Muir and Baker, 1976); (Phillips et al. 1999). With pesticide degradates entering major rivers, reservoirs, and groundwater, there is the potential for these compounds to be present in water abstracted for drinking water treatment (Heberer and Dünnbier, 1999). Whether these degradates are present in this raw water will depend on their rate of formation in the environment, the extent of their parental use in the particular catchment, and the physico-chemical properties and rate of degradation of themselves and their parents (Boxall et al. 2004c). The movement of these compounds to abstraction sources is more complex than pesticidal degradation and the subsequent movement through the environment of the degradates. The movement of the parent pesticide needs to be considered also because at any point along its ‘journey’ it can degrade and from additional degradates. Therefore, degradates with low mobility can occur a distance from the site of application (Brouwer et al. 1990). If degradates are present in raw water, then, it maybe desirable to remove them during water treatment. Limited drinking water standards specific to particular degradates have been set in the USA (aldicarb sulfone and sulfoxide), while in the EU degradate drinking water standards are covered by the 0.1 µg L-1 for pesticides (and their ‘relevant metabolites’). The term ‘relevant metabolite’ was introduced in the EU Directive 91/414/EEC (EU, 1994) and its subsequent amendments. This legislation concerns the placing of plant protection products on the market and subsequent guidance has been provided on determining the relevance of a degradate (e.g., EU, 2003). Water treatment processes designed to remove pesticides may not be as efficient at

©2008 AwwaRF. ALL RIGHTS RESERVED removing the smaller, more polar degradates. An important consideration during drinking water treatment is the additional formation of degradates from either the pesticides or the environmental degradates (Zhang and Pehkonen, 1999). Based on the literature review undertaken during this project, it was identified that the information available about the monitoring and measurement of degradates in the environment is dominated by the triazine and chloroacetamide herbicides. A large volume of data was available concerning the environmental occurrence of the cotton and corn herbicides from studies undertaken in the USA. Their environmental fate and that of their degradates has been documented for soil, sediment, surface waters including runoff, streams, rivers, estuaries, lakes and reservoirs, ground waters, rain and air. A large proportion of the available work focuses on atrazine, while cyanazine, metolachlor, and alachlor are also studied in detail. The main degradates under investigation are: deethylatrazine (DEA), hydroxyatrazine (HA) and deisopropylatrazine (DIA), cyanazine amide and the ethane sulfonic acids (ESA) and oxanilic acids (OA) of metolachlor and alachlor. In this Chapter, information from the literature and industry data is used to identify the nature and amounts of pesticide degradates that are formed in the environment through biotic degradation (e.g., soil) or abiotic degradation pathways such as surface and aqueous photolysis or hydrolysis. Information is also presented on their occurrence, degradation and sorption in the environment.

FORMATION IN THE ENVIRONMENT

Once pesticides are applied in the environment during either normal agricultural practice or via alternative uses such as domestic, industrial, and amenity, they are susceptible to biotic and abiotic degradation. The major abiotic processes include hydrolysis, photolysis, and oxidation/reduction. Hydrolysis is a chemical transformation process in which an organic molecule reacts with water. Substances that are potentially susceptible to hydrolysis include alkyl halides, amides, amines, carbamates, epoxides, nitriles, phosphoric acid esters, and sulphonic acid esters (Samiullah, 1990). Photolytic degradation can occur directly (where the substance itself absorbs solar radiation) or indirectly (where the energy is transferred from some other species). Biodegradation is one of the most important forms of degradation in the environment. It is generally a significant loss mechanism in soils and aquatic systems and is essential to wastewater treatment. Although higher organisms can metabolise a substance, it is the microbes that play the most important role in the degradation of a substance in environmental media. The majority of biodegradation reactions can be categorized as oxidative, reductive, or conjugative (Hill, 1978; Table 3.1).

Type of reaction Example

ß-oxidation Phenoxyalkanoate herbicides Oxidative dealkylation; N-dealhylation Alkyl carbamates, phenylureas, s-traizines O-dealkylation Organophosphorous pesticides, phenoxyalkanoate herbicides C-dealkylation Methoxychlor Thioether oxidation Carbophenothio, prometryn, aldicarb Decarboxylation Nicotinic acid Epoxidation Aldrin, heptachlor Aromatic hydroxylation 2,4-D, nicotinic acid Aromatic, non-heterocyclic ring cleavage Catechols, phenols, phenoxyalkanoate herbicides, carbaryl Aromatic, heterocyclic ring cleavage Paraquat. Picloram, amitrole Hydrolysis Carbamates, organophosphates, urea and aniline herbicides Hydrolytic dehalogenation TCA, dalapon, chlorobenzoates Halogen migration Anisoles, 2,4-D Reductive dehalogenation DDT Dehydrohalogenation p,p-DDT, Lindane Nitro-reduction parathion

Selected degradates identified in the environment can result from multiple pesticides or even from non-pesticidal sources. For example, the degradate DIA is a degradate of three triazine herbicides: atrazine, cyanazine, and simazine; while DEA is a degradate of atrazine, propazine, and cyprazine (Thurman et al. 1994; Scribner et al. 2000; Muir and Baker, 1976) (Figure 3.1). The chlorinated phenols, (e.g., 2,4-dichlorophenol, a degradate of the herbicide 2,4-D), can enter the environment either during their manufacture and use or via the degradation of phenoxycarboxylic acids (Health Canada, 1987). Therefore, when monitoring the occurrence of degradates in raw water sources such as rivers and groundwater, in some cases it may be difficult to identify the particular source of a degradate.

Cl Cl

N N N N

N N N N N N H H H H Cl Cl Cl simazine propazine

NN N N N N

N NN N N N N N N H H H H H H N cyanazine atrazine cyprazine

Cl Cl

N N N N

H 2 NNN N N NH2 H H DIA DEA Figure 3.1 Degradation of the triazine herbicides to DIA and DEA (adapted from (Scribner et al. 2000).

©2008 AwwaRF. ALL RIGHTS RESERVED A pesticide is ‘degraded’ its chemical structure changes, thereby forming a degradate. These chemical changes can be large structural changes or small alterations of a single structural moiety. Structural cleavage generally forms two much smaller compounds such as the hydrolytic cleavage of the sulfonylurea herbicides. The process of pesticide degradation does not have to be a reduction in structural size. Transformations can also slightly alter the structure of a pesticide, producing a structurally similar degradate such as the hydrolytic de-chloroination of the chloroacetamide herbicides (Roberts, 1998) (Figure 3.2). When a small modification to a pesticide’s structure occurs and the majority of the pesticide structure is still intact, it is possible for the degradate to maintain the same specific mode of action of the parent compound. Some pesticides are specifically designed to use a process such as this to enable greater efficiency. The precursor compound can be more stable or can enter the target organism more effectively. A transformation then takes place, producing the more active pesticide. Pesticides that act in this manner are known as pro-pesticides including the thiophosphate class of organophosphorus (OP) insecticides which undergo oxidative desulphurisation once in the target organism to the oxon forms, which are much more potent acetylcholinesterase inhibitors (Drabek and Neumann, 1985) (Figure 3.3). In the environment, the transformation of the pro-pesticide to the active form can occur. Current legislation in Europe for placing new pesticides on the market ensures that the environmental risk assessment process considers the active component of a pesticidal application (EU, 1994).

O O

Cl HO N O N O

alachlor N-(2,6-diethylphenyl)-2-hydroxy-N- (methoxymethyl)acetamide

Cl O NH2 S

N O N

Cl O H H N N NO S 2-chloro-4-hydroimidazolo[1,2-a] N O ON pyridine-3-sulfonamide N

O H2N NO

N imazosulfuron

4,6-dimethoxypyrimidine-2-ylamine Figure 3.2 The transformation and cleavage degradation pathways of chloroacetamide (e.g., alachlor) and sulfonylurea (e.g., imazosulfuron) herbicides.

P P O O N Cl O O N Cl O O chlorpyrifos chlorpyrifos oxon

Figure 3.3 The oxidative desulphurisation of the insecticide chlorpyrifos

When pesticides are released into the environment a number of different degradates can be produced. The extent of pesticide degradation and the identity and quantity of degradates formed depend on the degradation pathways and environmental conditions that are experienced (Roberts, 1998; Roberts and Hutson, 1999). Pesticide and degradate degradation, and hence, degradate formation in soil is influenced by soil properties and conditions. These can be inherent soil properties such as soil texture and pH or transient properties such as organic carbon content, microbial ecology, water, and oxygen content. Structurally identical and different degradates can be formed during different degradation pathways, e.g., when both aerobic and anaerobic soil degradation of carbaryl form 1-napthol while structurally different naphthoquinone degradates are formed (Figure 3.4). Due to the high total usage of pesticides in agriculture when compared to other applications (Donaldson, Kiely, and Grube, 2002), pesticide degradation in soil is one of the most important processes determining which degradates could be present in potential drinking water sources. Many factors determine the rate and route of pesticide degradation and hence, degradate formation. Once a pesticide has undergone a degradation step, additional degradates can then be formed from this degradate and alternative degradates formed from the pesticide via a different degradation pathway. Following a single application of atrazine, degradate concentrations identified in the vadose zone were in the order DEA > didealkylatrazine > DIA > HA. In the following season when atrazine was not applied, degradate concentrations were in the order didealkylatrazine > DEA > DIA > HA. This change in degradate concentration ratio is due to the degradation of the DEA and DIA to didealkylatrazine (Pashin et al. 2000). This branching degradation of pesticides, influenced by environmental conditions, can therefore produce a wide range of degradates.

4-hydroxyl carbaryl

OH O O O OH HN O OH

O carbaryl 1-napthol salicylic acid 1,4-naphthoquinone

5-hydroxy-1-naphthyl O methylcarbamate

O OH OH

HN 1-naphthyl-(hydroxymethyl) O carbamate

O 5-hydroxyl carbaryl 2-hydroxy-1,4-naphthoquinone Figure 3.4 Selected degradation pathways for the insecticide carbaryl (Boxall et al. 2004a).

The diversity of the microbial community is very important in the biotic degradation of pesticides. As an example, the biotic degradation rate of endosulfan is influenced by the degrading microbes; the fungal species Fusarium ventricosum that degrades endosulfan faster than the bacterium Pandoraea sp. (Siddique et al. 2003). Moreover, microbial communities can adapt to degrade compounds, increasing the degradation rate of a compound following its subsequent application and therefore, degradate formation (Smith and Aubin, 1991). However, not all pesticides show this increase in degradation rate following repeated application as some compounds show no change (e.g., chlorpyrifos), while other show a reduction (e.g., chlorothalonil) (Singh et al. 2002). Generally, the biotic degradation of compounds decreases with depth through the soil profile, due to the decrease in microbial biomass and organic carbon content. However, the degradation of the chlorpyrifos primary degradate, 3,5,6-trichloro-2- pyridinol, adheres to this principle while the degradation rate of the parent compound increases down the soil profile. This increase in the chlorpyrifos degradation rate was due to an increase in soil pH with depth in this specific soil (Baskaran et al. 2003). Where soil is amended with organic material such as manure or slurry, pesticide and degradate degradation rate in the top soil can be increased (Wagner and Zablotowicz, 1997; Benoit and Barriuso, 1997). The oxygen levels under which degradation occurs can drastically alter the degradation of pesticides and the formation of degradates. The degradation rate and pathway of a pesticide in soil, sediment or groundwater can vary depending on whether the environmental compartment is under aerobic or anaerobic conditions. The degradation rate of alachlor and the formation ratio of two degradates (alachlor ESA and alachlor OA) differ when under aerobic and anaerobic conditions (Graham et al. 2000). These two degradates of alachlor are commonly identified in aerobic environmental compartments (Aga and Thurman, 2001; Kalkhoff et al. 1998). Different degradates (e.g., acetyl alachlor and diethyl aniline) are identified under methnogenic and sulphate-reducing conditions (Novak et al. 1997).

A number of approaches are available for identifying the degradates of a pesticide include experimental methods and predictive approaches.

Experimental methods

The pathway of degradation of a substance in soil is typically determined according to Organisation for Economic Co-operation abd Development (OECD) guidelines (OECD, 2002). Soil is treated with radiolabelled test substance and incubated in the dark in biometer-type flasks or in flow-through systems under controlled laboratory conditions (at constant temperature and soil moisture). The soil used is typically a sandy loam or silty loam or loam or loamy sand with a pH of 5.5-8.0, an organic carbon content of 0.5-2.5% and a microbial biomass of at least 1% of the total organic carbon. After appropriate interval times, soil samples are extracted and analyzed for the parent compound and the degradates. Volatile products are also collected for analysis using appropriate adsorption devices. The studies are typically performed for up to 120 days. Following removal from the test system, the substrate is extracted and total radioactivity in the extracts is determined by liquid scintillation counting (LCS). Extracts can be further investigated using thin layer chromatography (TLC) and radioscanning, by HPLC with a radiomatic flow detector, or by fraction collection with LCS. Degradates can be identified by LC-MS, GC-MS and nuclear magnetic resonance (NMR). Sediment/water degradation studies are carried out using a similar approach to the soil degradation studies. Experiments are typically performed on sediments with a high and low organic matter contents and are carried out in static systems consisting of an anaerobic sediment and an aerobic water phase. The water/sediment systems are pre-incubated to establish an anaerobic environment. During pre-incubation pH, oxygen content and redox potential are carefully monitored. Radiolabelled test substance is added to the water phase and incubated for up to 14 weeks. CO2 evolution is monitored at regular intervals and both sediment and water phases are analyzed separately for parent compound, major degradates and bound residue.

Predictive approaches

Degradation route studies are complex and costly, and it is often very difficult to identify the minor degradates in a system. Information is available for a wide range of pesticides (e.g., Roberts, 1998; Roberts and Hutson, 1999), but limited information is available for other substances. An alternative to experimental testing might be to use structure-biodegradability relationships (SBR) to predict degradation pathways from the chemical structure of the parent compound. Predictive techniques such as SBR are commonly known as QSAR (quantitative structure property activity relationships). A number of systems have been developed for doing this including BESS (Punch et al., 1996), PPS (Hou et al. 2003) and CATABOL (Jaworska et al. 2002). BESS is a computerized system that simulates the biodegradation of compounds through sequential application of plausiable biochemical reactions (Punch et al. 1996). PSS is a web- based system that can predict biodegradation of most aliphatic and aromatic organic functional groups containing C, H, N, O and halogens (Hou et al. 2003). HCATABOL is a probabilistic approach to modeling biodegradation based on aerobic microbial transformation pathways generated from MITI-I tests and expert judgement (Jaworska et al. 2002). CATABOL has been evaluated for determining transformation pathways for pesticides in soil (Sinclair et al. 2003).

©2008 AwwaRF. ALL RIGHTS RESERVED Comparison of predictions with experimental observations indicated that only 24% of experimentally derived degradates are predicted correctly. Further development of this and other expert systems is therefore required before they can usefully be used to identify or predict degradates.

CHARACTERISTICS OF DEGRADATES OF MAJOR PESTCIDES

Data from experimental studies into the transformation of major use pesticides are summarized in Appendix 1. The data details the extent of formation (i.e., percentage of applied pesticide) for 215 degradates formed from 62 pesticides. 122 of these degradates were identified as being formed at ≥ 10% of the applied pesticide in one or more degradation studies (Figure 3.5; Table 3.2). Therefore, based on the definition in the EU, these compounds can be considered ‘major metabolites’. The extent of degradate formation is presented in Figure 3.5, where each identified degradate is represented by the extent of its formation in the degradation study where it is most prevalent. There are a number of degradates (8) with a formation >80% of the applied pesticide. Four of these compounds are pesticides that act as a pro-pesticide and their transformation to the active component can be expected at a high rate, e.g., diclofop-methyl, fluzifop-p-butyl, fluoroglucofen-ethyl and carbofuran. The data in Figure 3.5 include aerobic and anaerobic soil degradation, sterile hydrolysis, aquatic and soil photolysis, column and lysimeter leachate studies and degradation in water/sediment systems. The most common formation data available in the literature is degradate formation during pesticide degradation in aerobic soil; ~44% of data points are of this type.

20 Transformation products (n) 10

5 0 0 0 0 0 0 0 0 0 0 < 1 2 3 4 5 6 7 8 9 0 - < < < < < < < < < 1 ------0 5 0 10 20 30 40 50 60 70 80 9 Transformation product formation (% of pesticide)

Figure 3.5 Formation of pesticide degradates as a percentage of the parent pesticide (each degradate is represented by the degradation study where it was most prevalent)

©2008 AwwaRF. ALL RIGHTS RESERVED No conclusions should be drawn about the ratio of major to minor degradates identified in this review. Degradation studies and the relevant legislation are biased toward identifying those degradates formed in greater amounts because these that could pose the greatest risk. Due to restraints on time and money, limitations in analytical capabilities, and the perceived unimportance of degradates formed in small quantities, these compounds are rarely identified or quantified during degradation studies undertaken for the purposes of pesticide registration. For example, when the fate of alachlor is investigated, generally alachlor ESA, alachlor OA, and 2,6- diethylaniline are identified in surface water, groundwater, soil and sediment (e.g., Graham et al. 1999 ; Graham et al. 2000 ; Fava et al. 2000 ; Scribner et al. 2000 ; Osano et al. 2003). However, an extensive investigation into the occurrence of alachlor degradates in groundwater following agricultural application identified at least twenty different degradates, a number of which occurred in the ng L-1 range (Potter and Carpenter, 1995). Therefore, a number of degradates may be formed in quantities two or three orders of magnitude less than the major degradates of a pesticide. However, the importance of these compounds is probably negligible when compared to the possible risks posed by either the pesticide itself or its major degradate(s).

Table 3.2 Summary of pesticide degradates identified as formed at ≥ 10% of the applied pesticide in one or more degradation studies

Degradate a/b Parent pesticide

1,2,4-benzenetriol 2,4-D 2,4-dichloroanisole 2,4-D 2,4-dichlorophenol 2,4-D 2-([N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)carbomyl]methylsulfonyl) acetic acid acetochlor acetochlor oxanilic acid acetochlor N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide acetochlor N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide acetochlor 2,6-diethyl-N-methoxy-methoxanilic acid alachlor 2',6'-diethyl-N-methoxymethyl acetanilide alachlor 2,6-diethyl-N-methoxymethyl-2-sulpho-acetanilide alachlor alachlor ethane sulfonic acid alachlor alachlor oxamic acid alachlor 2-amino-4,6-dihydroxypyrimidine amidosulfuron 2-amino-4,6-dimethoxypyrimidine amidosulfuron HOE 101630 amidosulfuron HOE 101632 amidosulfuron HOE 101633 amidosulfuron HOE 101634 amidosulfuron product A (unidentified) amidosulfuron dihydroxy anilazine anilazine monohydroxy anilazine anilazine deethylatrazine atrazine DEHA atrazine deisopropyl deethylatrazine atrazine deisopropylatrazine atrazine hydroxyatrazine atrazine azoxystrobin acid azoxystrobin carbofuran benfuracarb carbofuran phenol benfuracarb N-hydroxy-methyl carbofuran benfuracarb 1,2,4-triazole bitertanol bitertanol benzoic acid bitertanol 1-isopropyl-3-phenyl urea buprofezin 1-tert-butyl-3-isopropyl-5-phenyl-2-biuret buprofezin buprofezin sulphoxide buprofezin 5-amino-4-chloropyridazin-3(2H)-one chloridazon 3-carbamyl-2,4,5-trichlorobenzoic acid chlorothalonil 3,5,6-chloro-2-pyridinol chlorpyrifos 2-amino-4-methoxy-6-methyl-1,3,5-triazine chlorsulfuron 2-chlorobenzene sulfonamide chlorsulfuron T1S cycloxydim T2 cycloxydim T2SO cycloxydim T2SO2 cycloxydim T3 cycloxydim TSO cycloxydim Ia cyhalothrin Ib cyhalothrin (continued) 22

©2008 AwwaRF. ALL RIGHTS RESERVED (continued) melamine cyromazine ethyl-m-hydroxyphenyl carbamate desmedipham compound II diazinon pyrimidinol diazinon 3,6-dichlorosalicylic acid dicamba 4-(2,4-dichlorophenoxy)phenol diclofop-methyl diclofop acid diclofop-methyl N-demethyldimefuron dimefuron O,O-dimethylphosphorothioic acid dimethoate O-desmethyldimethoate dimethoate DPX M6316 triazine amine DPX M6316 DPX M6316 triazine urea DPX M6316 Cl-Vacid esfenvalerate CONH2-fen esfenvalerate fenoxaprop-ethyl acid fenoxaprop-ethyl 2,2,3,3-tetramethyl cyclopropane carboxylic acid fenpropathrin 3-phenoxybenzoic acid fenpropathrin a-(2,2,3,3-tetramethylcyclopropyl)-3-phenoxybenzyl cyanide fenpropathrin a-carbomoyl-3-phenoxybenzyl-2,2,3,3-tetramethyl cyclopropane carboxylate fenpropathrin R0 15-6045 fenpropidin 1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile fenpyroximate M3 fenpyroximate M4 fenpyroximate compound V fluazinam compound VII fluazinam compound VIII fluazinam compound XII fluazinam RH-4515 fluoroglycofen-ethyl RH-5781 fluoroglycofen-ethyl RH-5782 fluoroglycofen-ethyl RH-5783 fluoroglycofen-ethyl RH-9985 fluoroglycofen-ethyl RH-9986 fluoroglycofen-ethyl RH-9987 fluoroglycofen-ethyl 1H-1,2,4-triazole flusilazole bis (4-fluorophenyl)methyl silanol flusilazole fluzifop acid fluzifop-P-butyl fomesafen amine fomesafen fomesafen amino acid fomesafen glufosinate 3-methyl phosphinico-proprionic acid ammonium glufosinate HOE 35956 ammonium glufosinate HOE 64619 ammonium glufosinate HOE 64620 ammonium glufosinate HOE 64621 ammonium glufosinate HOE 85355 ammonium HOE 72829 HOE 070542 HOE 83348 HOE 070542 HOE 87607 HOE 070542 HOE 88989 HOE 070542 1,5-bis(-p-tolyl)-1,4-pentadiene-3-one hydramethylnon (continued) 23

(continued) 2H-azolidino[3,4-b]quinoline-1,3-dione imazaquin 3-imino-2H-azolidino[3,4-b]quinolin-1-one imazaquin M1 imazaquin quinoline-2,3-dicarboxylic acid imazaquin quinoline-3-carboxylic acid imazaquin 1-(6-chloro-pyridine-3-ylmethyl)-2-imino-imidazolidine Imidacloprid 2-propenyl butyl-carbamate IPBC propargyl butyl carbamate IPBC acetic acid kathon 886 formic acid kathon 886 malonamic acid kathon 886 malonic acid kathon 886 N-methyl malonamic acid kathon 886 RH 886 oxide kathon 886 kresoxim-methyl acid kresoxim-methyl malathion dicarboxylic acid malathion 2-N-(2,6-dimethylphenyl)-2-methoxyacetylamino propanoic acid metalaxyl carbinol metolachlor 2-(aminosulfonyl) benzoic acid metsulfuron-methyl methyl-2-(aminosulfonyl)benzoate metsulfuron-methyl saccharin metsulfuron-methyl N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide propyzamide

a - a full list of degradates and their formation data available in Appendix 1 b - Appendix 7 contains IUPAC names for degradates represented by abbreviations

FATE OF DEGRADATES IN THE ENVIRONMENT

Like all organic substances, once formed in the environment, a degradate may be degraded by biotic and abiotic processes and may be transported between the different environmental compartments. A large body of data is available on the persistence and mobility of pesticide degradates (Appendix 2 and 3).

Degradation in the environment

Available data on the degradation rate of pesticide degradates in different environmental compartments and under different conditions is provided in Appendix 2. This data comprises DT50 data and half-life data (t½) DT50 is the time required for one-half the initial quantity or concentration of a compound to dissipate from a system, whilst half-life is the time taken for the concentration of a pesticide in a compartment to decline by one half (Holland 1996). The data are summarized in Figure 3.6 and demonstrate that degradates can be degraded by a range of processes. Fifteen of the degradates, 55%, are moderately to very persistent in aerobic and anaerobic soil. When degradation data for pesticide degradates (Appendix 2) is compared to their parental compounds (Figure 3.6), 73.6% of the degradates have equal or greater persistence than the pesticide (Figure 3.6 contains data collected in this review collated with data presented in Boxall et al. 2004b). When summarizing these data, it is not possible to generalize that degradates are more persistent than parent pesticide, because the dataset is probably skewed. Data pertaining to more persistent degradates is probably more likely to be reported during a

©2008 AwwaRF. ALL RIGHTS RESERVED study while data concerning rapidly degrading degradates is unlikely to be reported at all (Boxall et al. 2004b). Although no generalizations can be made about a pesticide and its degradates persistence, this dataset includes a number of degradates that are more persistent than the pesticide. Therefore, these compounds can remain in the environment longer than the parent and have the potential to contaminate raw water sources.

sediment 15 anaerobic soil degradation water sediment system sterile hydrolysis 10 surface water sewage

Transformation products (n) aerobic soil degradation aqueous photolysis 5

0 < 5 5 - 21 22 - 60 > 60

Degradation DT50/t½ (days)

Figure 3.6 The degradation of pesticide degradates, classified according to the Soil Survey and Land Research Centre (SSLRC) persistence classification.

1000

/t½ (days) /t½ 100 50

Transformation product DT 0.1

0.01 0.01 0.1 1 10 100 1000 10000

Pesticide DT50/t½ (days)

Figure 3.7 The comparative persistence of pesticides and their degradates in various environmental media; aquatic photolysis (○), surface water (●), sterile hydrolysis (□), aerobic soil (■), anaerobic soil (Δ), sediment (▲) and sediment/water system (×). The diaganol line represents equal persistence.

Routes into environmental waters

NON-AGRICULTURAL

The monitoring and measurement of pesticides and their degradates is understandably dominated by the occurrence of agricultural herbicides in agricultural areas. However, pesticides are also widely used in other areas which could be an important source of degradates in environmental waters. As discussed in Chapter 2, non-agricultural pesticide market sectors include industrial, commercial, government and domestic (Donaldson et al. 2002). Due to the method or site of application, pesticides used in these sectors can have the potential for direct entry into surface waters. Following herbicidal application to hard surfaces such as asphalt and concrete, more than half of applied atrazine and diuron can be lost to the highway drainage system during the first 5 mm of rainfall (Ramwell et al. 2002). In the UK, five herbicides (2,4- D, dichlobenil, diquat, glyphosate, terbutryn)and one plant growth regulator (maleic hydrazide) are approved for use in or near water (Whitehead, 2004). Obviously, this method of application can provide the pesticides with direct entry route into surface waters where they could degrade and produce degradates in relatively large quantities. In contrast to agricultural streams, the total insecticide concentration exceeds that of the total herbicide concentration in urban streams (Hoffman et al. 2000). However, no insecticidal degradates were detected in urban streams when sampled during one study, with DEA the only degradate identified (Hoffman et al. 2000).

Effects of climate and season

One of the dominate factors affecting the occurrence of degradates in environmental waters (surface and ground) is climatic conditions. Peak concentrations of triazine degradates (DEA and DIA) reach maximum concentrations following rainfall soon after atrazine application and a dry summer (Thurman et al. 1994). Following dry summer conditions, the first large rainfall event can ‘flush’ degradates from the soil resulting in peak concentrations in tile drains. It is hypothesized that during the summer, degradates quantities increase and are stored in soil which are then readily transported to tile drains by heavy rainfall. Metolachlor ESA and metolachlor OA concentrations in tile drain samples peaked in the first tile drain flow in November following a dry summer. These concentrations quickly declined once the stored degradates had been flushed out of the soil (Phillips et al. 1999). These large peak concentrations are observed in subsequent surface waters such as streams and rivers (Clark and Goolsby, 2000; Boyd, 2000; Albanis and Hela, 1998) .

Mobility in the environment

One of the most important physico-chemical properties of a degradate for determining whether it will be mobile and enter potential abstraction water is its organic carbon sorption coefficient (Koc). The data collected during this review is provided in Appendix 3 and summarized in Table 3.3. This property is a contributing factor to the extent to which a chemical will adsorb to the soil. Compounds with a high Koc bind to the organic material in soil and hence, have a low degree of mobility. Boxall et al. (2004b) investigated the relationship between the sorption of degradates and their pesticidal parents from Koc data collected from numerous databases. Approximately one third of the degradates had a Koc value of at least an order of magnitude lower than the corresponding parent compound. During this study, sorption data was collated from studies where both the parent and the transformation Koc were determined. This was done so that comparative analysis would not be affected by inter-laboratory variability. When Koc is determined experimentally, it is usual to use a number of different soils with varying properties (e.g., pH, clay content and % organic carbon content). This usually provides a range of Koc values for each compound from the range of soil types used. Therefore, when comparing the mobility of a pesticide to that of its degradate(s), the minimum Koc value for each compound derived in a study was considered (Figure 3.8). 10% of the degradates had a Koc at least an order of magnitude lower than their pesticide. When the mobility of the degradates (including those without pesticide comparative data) are classified according to the SSLRC mobility classification (Hollis, 1991), 50% of the degradates are categorized as mobile to very mobile (Koc <75) with 35.5% categorized as slightly mobile (Koc 75 - 499).

10000

1000

100 Transformation product Koc Transformation 10

0.1 0.1 1 10 100 1000 10000 100000 Pesticide Koc Figure 3.8 The comparative sorption of pesticide degradates and their parent pesticides

The lower sorption coefficients and increased solubility of two atrazine degradates, (DEA and DIA), indicate that they have a greater potential to move through the soil profile to groundwater than does the parent compound (Mills and Thurman, 1994). The rate of degradation and the sorptive behavior of pesticides and their degradates will determine their persistence in soil and their mobility to surface and ground waters. Degradates of the triazine herbicides, cyanazine (Reddy et al. 1997) and atrazine (Krutz et al. 2003), show equal or lower levels of sorption to a range of soil types than the parent compound. This could increase their mobility and thus, the potential to enter surface and ground waters. Moreover, the sorption of degradates of the chloroacetamide herbicides alachlor and metolachlor is approximately equal to or less than that for the parent compounds. However, the rapid rate of degradation (<2.4 days) for all the degradates of these two herbicides will influence the extent of their persistence and hence mobility (Fava et al. 2000).

a/b Degradate Parent pesticide Koc

2,4-dichlorophenol 2,4-D 182.9 - 481.5 2-chloro-2',6'-diethylacetanilide alachlor 148 2-hydroxy-2',6'-diethylacetanilide alachlor 45 2,6-diethylaniline alachlor 357 alachlor ethane sulfonic acid alachlor 182 4,6-dihydroxypyrimidin-2-yl-urea amidosulfuron 0.4 2-amino-4,6-dimethyoxypyrimidine amidosulfuron 89 - 11289 HOE 101630 amidosulfuron 3 - 63 dihydroxy anilazine anilazine 144 - 512 deethylatrazine atrazine 12.2 - 300 deisopropylatrazine atrazine 31 - 400 diaminochlorotriazine atrazine 31 - 76 hydroxyatrazine atrazine 103 - 13797 2-amino-N-isopropyl benzamide bentazone 54 - 260 N-methyl bentazone bentazone 90 - 370 3,5,6-trichloro-2-pyridinol chlorpyrifos 70 - 159 3,5,6-trichloro-2-pyridinol chlorpyrifos 76 - 126 desmethylpropanenitrile cyanazine cyanazine 15 - 133 hydroxyacid cyanazine cyanazine 11 - 130 deethylcyanazine cyanazine 26 - 82 cyanazine amide cyanazine 16 - 75 chloroacid cyanazine cyanazine 7 - 11 3,6-dichlorosalicylic acid dicamba 504 diclofop acid diclofop-methyl 191 - 334 4-chlorophenol dichloroprop 95.4 - 227.8 HOE 35956 glufosinate 16 ammonium imidacloprid-guanidine imidacloprid 189 - 211 imidacloprid-guanidine-olefin imidacloprid 2129 - 3805 imidacloprid-urea imidacloprid 2314 - 3083 kresoxim-methyl acid kresoxim-methyl 17 - 24 2-methyl-4-chlorophenol MCPA 123.8 - 261.1 metolachlor ethane sulfonic acid metolachlor 195 2-ethyl-6-methylaniline metalochlor 197

a - a full list of degradate data available in Appendix 3 b - Appendix 7 contains IUPAC names for degradates represented by abbreviations

OCCURRENCE IN THE ENVIRONMENT

Whether pesticides are present in environmental waters (surface water and groundwater) following their agricultural application is determined by a large number of factors including climatic conditions (e.g., rainfall and temperature), mass transfer processes, chemical properties (e.g., solubility, degradation and sorption), agricultural practices (e.g., application rate, tillage practices land use), and specific location properties (e.g., soil properties, hydrological properties,

©2008 AwwaRF. ALL RIGHTS RESERVED topography) (Lerch and Blanchard, 2003). All of these factors are also important in determining whether degradates are present in surface water and groundwater. However the importance of these factors in determining the fate of degradates when compared to pesticides will differ. If a pesticide degrades rapidly in soil, then it is unlikely that this compound will be detected in environmental waters; however, its degradates could form in relatively large quantities. Therefore, rapid pesticide degradation is an advantageous property in preventing pesticide contamination but possibly disadvantageous for preventing its degradates from entering environmental waters. When the chloroacetamide herbicides are applied at the same rate during normal agricultural practice, the ESA degradate of alachlor is present at higher concentrations than metolachlor in soil, 43.5 µg kg-1 and 11.91 µg kg-1 respectively. This difference is due to the relatively longer half-life of metolachlor (15.5 d) in soil and thus slower formation of metolachlor ESA when compared to alachlor (8 d) (Aga and Thurman, 2001). However, pesticide usage will be of greater importance in determining the degree of degradate occurrence in environmental waters. In 1997, 5.8 - 7.3 million kg of alachlor was used in the agricultural sector compared to 28.6 - 31.3 million kg of metolachlor (Kiely et al. 2004). Therefore even though when applied at the same rate, alachlor ESA will be formed in greater amounts in soil, the higher usage of metolachlor in the agricultural sector will mean that its degradates will be detected at higher concentration and more frequently. Moreover, during monitoring studies of surface and ground waters, metalchlor ESA is detected at higher concentrations and more frequently than the alachlor ESA (Kalkhoff et al. 1998; Kolpin et al. 1998). Pesticide degradates have been detected in numerous environmental compartments: soil, soil leachate, tile drains, surface waters including agricultural ditches, streams, rivers, reservoirs, canals, ponds, lakes and estuaries, groundwater, sediment, air including gaseous, and particulate phases and rain (Appendix 4). Table 3.4 provides a summary of this occurrence in soil, surface water, groundwater, raw source water, and finished drinking water. A number of pesticide degradates have been detected in the environment, with 50 detected in soil, 29 detected in groundwater and 26 detected in surface waters.

©2008 AwwaRF. ALL RIGHTS RESERVED Table 3.4 A summary of pesticide degradate environmental occurrence date Environmental Degradate a/b Parent pesticide Concentration compartment Soil 3-chlorallyl alcohol 1,3-dichloropropene ND 2,4-dichlorophenol 2,4-D 5 - 6 mg kg-1 2,6-diethylaniline alachlor ND 2-chloro-2',6'-diethylacetanilide alachlor ND alachlor ethane sulfonic acid alachlor 0.08 - 0.142 mg kg-1 alachlor ethane sulfonic acid alachlor 0.0435 - 0.21 mg kg-1 deethylatrazine atrazine < 0.001 - 0.12 mg kg-1

deethylhydroxyatrazine atrazine 47 ± 4 - 17 ± 2 μg kg-1 deisopropylatrazine atrazine < 0.001 - 0.027 mg kg-1

deisopropylhydroxyatrazine atrazine 0.021 - 0.074 mg kg-1 hydroxyatrazine atrazine < 0.001 - 0.5 mg kg-1

carbofuran benfuracarb < 1 - 6.3 mg kg-1 1-(2,4-dichlorophenyl) ethan-1-ol chlorfenvinphos ND - 0.3 mg kg-1 2,4-dichloroacetophenone chlorfenvinphos 0.3 - 0.4 mg kg-1

2,4-dichlorobenzoic acid chlorfenvinphos 4.7 - 7.9 mg kg-1

2,4-dichlorophenacyl chloride chlorfenvinphos 0.1 - 4.8 mg kg-1 2,4-dihydroxybenzoic acid chlorfenvinphos 1.1 - 2.5 mg kg-1

2-hydroxy-4-chlorobenzoic acid chlorfenvinphos 3.2 - 5.7 mg kg-1 dichlorobenzyl alcohol chlorfenvinphos 0.5 mg kg-1

trichloroacetophenone chlorfenvinphos 0.1 mg kg-1

SDS1449 chlorthal-dimethyl ND - 0.11 kg ha-1 SDS954 chlorthal-dimethyl ND - 2.09 kg ha-1 (4-amino-6-chloro(1,3,5-triazin-2- cyanazine 0.03 - 0.08 mg kg-1 yl))ethylamine 2-[(4-amino-6-chloro(1,3,5-triazin-2- cyanazine < 0.01 - 0.02 mg kg-1 yl))amino]-2-methylpropanenitrile 2-chloro-4-(1-carbonyl-1- cyanazine < 0.01 - 0.08 mg kg-1 methylethylamino)-6-amino-1,3,5-triazine cyanazine acid cyanazine 0.72 - 1.66 mg kg-1

cyanazine amide cyanazine <0.01 - 1.1 mg kg-1

cyanazine hydroxy acid cyanazine 0.1 - 0.79 mg kg-1 3-phenoxybenzaldehyde cypermethrin 0.001 - 0.01 mg kg-1 3-phenoxybenzoic acid cypermethrin 0.001 - 0.01 mg kg-1 CCA cypermethrin 0.001 - 0.01 mg kg-1 melamine cypromazine 0.05 - 1.4 mg kg-1 o,p’-DDD DDT 16 - 25.8 mg kg-1 o,p’-DDE DDT > 0.02 mg kg-1 p,p’-DDD DDT 8 - 10 mg kg-1 p,p’-DDE DDT 18.9 mg kg-1 ethyl-m-hydroxyphenyl carbamate desmedipham ND - 0.59 mg kg--1 diazoxon diazinon ND 2,5-dihydroxy-3,6-dichlorosalicylic acid dicamba 0.03 - 0.1 mg kg-1 3,6-dichlorosalicylic acid dicamba 0.05 - 1.25 mg kg-1 diclofop acid diclofop-methyl 0.01- 0.28 mg kg-1 2,4-difluoroaniline diflufenican ND 3-(trifluoromethyl)phenol diflufenican ND DM2 diflufenican ND - 0.021 mg kg-1 DM3 diflufenican ND - 0.027 mg kg-1 DM4 diflufenican ND - 0.024 µg kg-1 N-demethyldimefuron dimefuron 0.1 mg kg-1 RH-6467 fenbuconazole 0.005 - 0.047 mg kg-1 RH-9129 fenbuconazole ND - 0.05 mg kg-1 (continued)

Environmental Degradate a/b Parent pesticide Concentration compartment Soil continued RH-9130 fenbuconazole ND - 0.063 mg kg-1 fomesafen amine fomesafen <0.02 mg kg-1 3-methyl phosphinico-proprionic acid glufosinate-ammonium ND - 0.2 mg kg-1 4-chloro-2-methylphenol MCPA 5 - 6 mg kg-1 metolachlor ethane sulfonic acid metolachlor 0.0036 - 0.128 mg kg-1 2-hydroxyquinoxaline quinalphos ND - 66 µg kg-1 quinoxaline-2-thiol quinalphos ND - 42 µg kg-1

Vadose zone and column leachate 2,6-diethylaniline alachlor 1 µg L-1 2-chloro-2’,6’-diethylacetanilide alachlor 2.2 - 2.7 µg L-1 2-hydroxy-2’,6’-diethylacetanilide alachlor 0.8 µg -1 alachlor ethane sulfonic acid alachlor 3 - 73 µg L-1 deethylatrazine atrazine 0.3 - 29 µg L-1 deisopropylatrazine atrazine < 0.02 - 15 µg L-1 didealkylatrazine atrazine 0.2 - 1.25 µg L-1 hydroxyatrazine atrazine 0.08 - 0.37 µg L-1 RH-6467 fenbuconazole trace RH-9129 fenbuconazole trace RH-9130 fenbuconazole trace 2-ethyl-6-methylaniline metolachlor 0.6 µg L-1

Surface runoff acetochlor oxanilic acid acetochlor ND - 0.08 µg L-1 alachlor ethane sulfonic acid alachlor ND - 48.84 µg L-1 alachlor oxanilic acid alachlor ND - 0.17 µg L-1 deethylatrazine atrazine 0 - 29 µg L-1 deisopropylatrazine atrazine 0 - 12.14 µg L-1 metolachlor ethane sulfonic acid metolachlor ND - 1.26 µg L-1 metolachlor oxanilic acid metolachlor ND - 0.29 µg L-1

Surface water 2,4-dichlorophenol 2,4-D ND acetochlor ethane sulfonic acid acetochlor < 0.2 - 1.6 µg L-1 acetochlor oxanilic acid acetochlor ND - 1.4 µg L-1 2,6-diethylaniline alachlor ND - 0.924 µg L-1 2-chloro-2’,6’-diethylacetanilide alachlor ND - 0.35 µg L-1 2-hydroxy-2’,6’-diethylacetanilide alachlor ND - 0.9 µg L-1 alachlor ethane sulfonic acid alachlor < 0.2 - 27.8 µg L-1 alachlor oxanilic acid alachlor ND - 0.54 µg L-1 aldicarb sulfone aldicarb ND aldicarb sulfoxide aldicarb ND hydroxyatrazine atrazine < 0.2 - 8.8 µg L-1 deethylatrazine atrazine, cyprazine and ND - 28 µg L-1 propazine deisopropylatrazine atrazine, cyanazine and ND - 15 µg L-1 simazine 8-hydroxy-bentazone bentazone ND - 27 µg L-1 3-hydroxycarbofuran carbofuran ND cyanazine amide cyanazine ND - 3.3 µg L-1 deethylcyanazine cyanazine ND - < 0.05 µg L-1 deethylcyanazine amide cyanazine < 0.05 µg L-1 p,p’-DDE DDT ND p,p’-DDE DDT 0.004 µg L-1 2-isoprpyl-6-methyl-4-hydroxypyrimidine diazinon ND diazioxon diazinon ND dimethenamid ethane sulfonic acid dimethenamid 0.05 µg L-1 dimethenamid oxanilic acid dimethenamid 0.05 µg L-1 dichloromethylphenylurea diuron 0.45 µg L-1

dichlorophenylurea diuron 0.2 µg L-1 (continued) 32

Environmental Degradate a/b Parent pesticide Concentration compartment 3,4-dichloroaniline diuron and propanil 0.31 - 0.9 µg L-1 Surface water continued endosulfan sulphate endosulfan 0.006 µg L-1v flufenacet ethane sulfonic acid flufenacet 0.06 µg L-1 flufenacet oxanilic acid flufenacet 0.05 µg L-1 trifluoromethylphenyl urea fluometuron ND alpha-HCH gamma-HCH ND 4-chloro-2-methylphenol MCPA ND metolachlor oxanilic acid metolachlor 1 - 10 µg L-1 metolachlor ethane sulfonic acid metolachlor 0.1 - > 20 µg L-1 metolachlor oxanilic acid metolachlor ND - 1.3 µg L-1 demethylnorflurazon norflurazon 0.17 µg L-1 deisopropylprometryn prometryn ND

Groundwater 2,4-dichlorophenol 2,4-D 4 µg L-1 acetochlor ethane sulfonic acid acetochlor ND - 8.6 µg L-1 acetochlor oxanilic acid acetochlor ND - 11.5 µg L-1 2',6'-diethylacetanilide alachlor < 0.002 - 0.13 µg L-1 2,6-diethylanailine alachlor < 0.002 - 0.085 µg L-1 2',6'-diethylformanilide alachlor < 0.002 - 0.087 µg L-1 2'-acetyl-6'-ethylacetanilide alachlor 0.028 - 0.12 µg L-1 2'-acetyl-6'-ethyl-N- alachlor 0.068 - 0.24 µg L-1 methoxymethyl)acetanilide 2-chloro-2'-ethyl-6'-ethyl-N- alachlor < 0.002 - 0.31 µg L-1 (methoxymethyl)acetanilide 2-hydroxy-2',6'-diethyl-N- alachlor < 0.002 - 0.1 µg L-1 methoxymethyl)acetanilide 2-hydroxy-2',6'-diethyl-N-methyl)acetanilide alachlor < 0.002 - 0.13 µg L-1 7-ethylindoline alachlor < 0.002 - 0.035 µg L-1 alachlor ethane sulfonic acid alachlor ND - 9.32 µg L-1 alachlor oxanilic acid alachlor ND - 33.4 µg L-1 N-(2,6-diethylphenyl) methylene alachlor < 0.002 - 0.01 µg L-1 N-(2,6-diethylphenyl)-N- alachlor 0.1 - 0.55 µg L-1 (methoxymethyl)acetamide α-N-[(2'-6'-diethylphenyl)amino]ethanol alachlor <0.00 2 - 0.48 µg L-1 hydroxyatrazine atrazine ND - 1.3 µg L-1 deethylatrazine atrazine and propazine ND - 5 µg L-1 deisopropylatrazine atrazine, cyanazine, simazine ND - 1.17 µg L-1 cyanazine amide cyanazine ND - 0.64 µg L-1 deethylcyanazine cyanazine ND deethylcyanazine amide cyanazine ND dacthal diacid dacthal 2.22 µg L-1 dacthal mono acid and dacthal diacid dacthal ND - 158.2 µg L-1 combined p,p’-DDE DDT 0.006 µg L-1 p,p’-DDE DDT 0.03 µg L-1 AMPA glyphosate 1.6 µg L-1 α-HCH lindane 0.059 µg L-1 metolachlor ethane sulfonic acid metolachlor ND - 8.6 µg L-1 metolachlor oxanilic acid metolachlor ND - 15.3 µg L-1 Raw source water Reservoir deethylatrazine atrazine 0.14 - 0.38 µg L-1 deisopropylatrazine atrazine 0.08 - 0.14 µg L-1 hydroxyatrazine atrazine 0.8 µg L-1 azinphos-methyl-oxon azinphos-methyl 0.263 µg L-1

(continued) 33

Environmental Degradate a/b Parent pesticide Concentration compartment Reservoir continued disulfoton sulfone disulfoton 0.013 µ g L-1 disulfoton sulfoxide disulfoton 0.06 µg L-1 fenamiphos sulfone fenamiphos 0.005 µg L-1 fenamiphos sulfoxide fenamiphos 0.021 µg L-1 malaoxon malathion ND

Abstraction wells o-p’-DDA DDT 0.28 µg L-1 p-p’-DDA DDT 1.7 µg L-1

Finished drinking water azinphos-methyl-oxon azinphos-methyl 0.026 µg L-1 disulfoton sulfone disulfoton ND disulfoton sulfoxide disulfoton ND fenamiphos sulfone fenamiphos 0.011 µg L-1 fenamiphos sulfoxide fenamiphos 0.022 µg L-1 malaoxon malathion 0.106 µg L-1

a - a full list of degradate data available in Appendix 4 b - Appendix 7 contains IUPAC names for degradates represented by abbreviations

Soil

Degradates can be expected to be present in soil following the application of the parent compound if it is susceptible to biotic or abiotic degradation. The review, identified six degradates have been detected in soil at concentrations greater than 5 mg kg-1: carbofuran, 2- hydroxy-4-chlorobenzoic acid, 2,4-dichlorobenzoic acid, p,p’-DDD, o,p’-DDD, and p,p’-DDE. The three DDT degradates were detected in soil from a former cattle tick dip site in Australia (Van Zweiten et al. 2001). Therefore, these concentrations can be considered an exception rather than the rule as sampling was targeted at a known hotspot. Similarly, the high concentrations of the chlorfenvinphos degradates, 2-hydroxy-4-chlorobenzoic acid ( 3.2 - 5.7 mg kg-1) and 2,4-dichlorobenzoic acid (4.7 - 7.9 mg kg-1) in soil were detected following a targeted sampling strategy (reported in PSD, 1994k). Chlorfenvinphos was applied around the stem of cauliflower and brussel sprout plants, with subsequent soil samples collected 10 cm around the base of the plants again targeting the sampling to known hotspots, which may not be representative of the field as a whole. The final degradate identified was the active component of the insecticide benfuracarb, carbofuran (6.3 mg kg-1) (PSD, 1998a). This pro-pesticide utilizes the degradation of benfuracarb to form the potent acetylchloinesterase inhibitor carbofuran and, in soil, undergoes hydrolysis to carbofuran (Roberts and Hutson, 1999), so high concentrations can be expected.

Surface water

Whether degradates are present in surface waters at larger or smaller levels than the parent compound depends on the pesticide and degradates concerned. Seven degradates have been identified in tile drain water (Appendix 4). Four of these have been observed at peak

©2008 AwwaRF. ALL RIGHTS RESERVED concentrations greater than 3 µg L-1: cyanazine amide, deethylatrazine, metolachlor OA and metolachlor ESA. Following the agricultural application of atrazine and cyprazine, the peak concentrations observed in tile drains were larger for the parent compounds for two consecutive seasons than for their degradate DEA. However, the total loss over the same period is greater for DEA than for either herbicide. Total losses via tile drains of two cyanazine degradates (cyanazine amide and DIA) are an order of magnitude greater than the parent compound, loses of DIA formed solely from atrazine are an order of magnitude less than the parent compound (Muir and Baker, 1976). Metolachlor degradates (metolachlor ESA and metolachlor OA) were detected in tile drain samples at concentrations at least two orders of magnitude greater than their herbicidal parent (Phillips et al. 1999). A study of streams in the Midwestern USA monitored for triazine and chloroacetamide herbicides and their degradates (Kalkhoff et al. 2003). The degradates monitored were the ESA and OA of alachlor, acetochlor, and metolachlor and the triazine degradates cyanazine amide, DEA, DIA, and HA. The frequency of detection of degradates in 70 streams varied from 23 to 96%, with seven degradates detected in more than 50% of the samples. Multiple degradates were detected in all samples analyzed (Kalkhoff et al. 2003). In a study of streams and rivers of Northern Missouri and Southern Iowa, DEA, DIA, HA, atrazine, and cyanazine amide were detected in > 95% of the samples (Lerch and Blanchard, 2003). In surface water, the two main metolachlor degradates, ESA and OA, were the major residue of metolachlor present (Phillips et al. 1999). When these surface waters will be used for drinking water supply, it is important to determine in which phase the contaminants are found. In one study no atrazine and alachlor degradates were detected in suspended sediment in the Mississippi River and its tributaries, while both parents and their degradates were detected in the dissolved phase (Pereira and Rostad, 1990). This is important in determining which processes will be the most effective in removing these compounds during water treatment. Ultimately when degradates are present in rivers and streams, they will be transported to estuarine and marine environments. The annual load of atrazine discharge to the Gulf of Mexico in 1993 was estimated at 642 t (Clark et al. 1999). These calculations did not take into account the discharge of atrazine degradates which could drastically increase the total atrazine residue. The estimated discharge of DEA into the Greek Amvrakikos Gulf is greater than atrazine, 127.5 g day-1 and 122.7 g day -1, respectively (Albanis and Hela, 1998).

Groundwater

Degradates have been detected in groundwater at higher concentrations (Albanis et al. 1998; Ferrer et al. 2000) and more frequently (Kolpin et al. 2000; Kolpin et al. 2001) than their parental compounds. Thirty degradates have been identified in groundwater during monitoring studies (Appendix ). Primarily it is the degradates of the triazines (i.e. atrazine, cyanazine and simazine) and the chloroacetamides (i.e. alachlor, acetochlor and metolachlor) that have been detected in groundwater. Twenty-four degradates observed in groundwater originate from these six herbicides while monitoring data concerning degradates from other from pesticide chemical groups are limited. The presence of degradates in groundwater depends on the aquifer type, well depth, surrounding geography, time of sampling (i.e. pre or post application), extent of pesticide usage, degradate formation, mobility, and concentration in soil during groundwater recharge (Kolpin et al. 1997; Burkart and Kolpin, 1993; Blanchard and Donald, 1997; Kolpin et al. 1996a). The peak concentration of any degradate identified in this review was 158.2 µg L-1 from

©2008 AwwaRF. ALL RIGHTS RESERVED the combined concentration of dacthal diacid and dacthal monoacid in a groundwater sample collected from the Malheur River Basin, Oregon (Monohan et al. 1995). As well as the lateral movement of vadose zone water, the transport of degradates to groundwater has been attributed to the hydraulic connection to surface waters such as rivers. The movement of degradates from rivers, through aquifers and into collector wells, driven by the collection of water has been identified as a means for pesticides and their degradates to enter drinking waters (Verstraeten et al. 1999). Once degradates have entered groundwater, their subsequent movement can be more (e.g., DIA) and less (e.g., DEA) retarded when compared to their parents (e.g., atrazine) (Widmer and Spalding, 1995). In comprehensive monitoring programs of pesticides and their degradates in groundwater, degradates are some of the most frequently detected compounds (Kolpin et al. 1996b; Kolpin et al. 1997; Kolpin et al. 1998; Kolpin et al. 2000). Moreover, p,p’-DDE, a degradate of the insecticide DDT, is still being detected in groundwater decades after a ban on the use parent compound was imposed (Kolpin et al. 1996b). The detection frequency of individual herbicides in groundwater is increased considerably when you consider their degradates (Kolpin et al. 1998). Moreover, for a number of herbicides, the majority of the total herbicide concentration was in the form of degradates (Kolpin et al. 2000; Kolpin et al. 2001). Therefore, to fully establish the effect pesticide use has on groundwater, it is necessary to quantify the degradates present. Generally, when groundwater monitoring for degradates is undertaken, it is a few primary degradates that are actively sought for each pesticide. However, a range of additional degradates present in low concentrations will also be present in the groundwater.

OCCURRENCE IN DRINKING WATER SUPPLIES AND FATE DURING DRINKING WATER TREATMENT

Pesticide degradates have been regularly identified in groundwater and surface waters (Appendix 4). Hence, degradates must be present in raw water abstracted from these sources. There is therefore, the potential for these degradates to be present in finished drinking water if they are not removed during the treatment process. Five OP insecticide degradates have been identified in water-supply reservoirs. Azinphos-methyl oxon, the active form of the pesticide azinphos-methyl has been monitored at a mean concentration of 0.263 µg L-1 in the raw water for eleven drinking water treatment plants in the USA (Nguyen et al. 2004). Moreover, the three most commonly identified atrazine degradates, DEA, DIA, and HA have been measured at 0.38, 0.14 and 0.8 µg L-1 in reservoirs (Solomon et al. 1996). DDA is a polar degradate of the organochlorine insecticide DDT, the use of which has been banned for a number of decades. However, in Germany, several drinking water wells have been closed to keep the DDA concentrations below the 0.1 µg L-1 drinking water tolerance level set by the EU (Heberer and Dünnbier, 1999). Two areas of importance concerning the fate of pesticide degradates during drinking water treatment are, their removal from raw water; and their possible transformation during treatment. Treatment processes such as coagulation, flocculation, sedimentation, and membrane filtration will assist in the removal of degradates associated with any suspended sediment in the raw water. Activated carbon adsorption, reverse osmosis, and nanofiltration can assist in the removal of degradates associated with the aqueous phase (Wang and Song, 2004), there is the potential for disinfection processes used during water treatment such as oxidation and advanced

©2008 AwwaRF. ALL RIGHTS RESERVED oxidation utilizing chlorine, ozone, hydrogen peroxide, and UV to transform organic compounds present in the raw water to additional compounds that need to be considered (USEPA, 2001). It is the presence and transformation of both pesticides and their environmental degradates to additional water treatment degradates that could pose a risk to human health. There is very limited data available in the literature identifying which degradation pathways pesticides and their environmental degradates would undergo during water treatment. There are a number of processes utilized during water treatment that remove pesticides and their degradates, however, chemical treatments can transform pesticides and their degradates into additional compounds (USEPA, 2001). Data are available on the removal of pesticides from raw water by various water treatment processes, such as advanced oxidation with ozone and UV radiation (Collivignarelli and Sorlini, 2004), nanofiltration (Van der Bruggen et al. 2001), and granular activated carbon (Feleke and Sakakibara, 2001). Generally, pesticide degradates are smaller and more polar than the parent compounds which could decrease the removal efficiency during treatment processes. However, only limited data are available on water treatment process removal efficiencies of pesticide environmental degradates. The oxidative desulphorisation of OP insecticides occurs during chlorination when the pesticides are present in raw water. This is where the thiophosphate moiety (P=S) is transformed to a P=O moiety (Zhang and Pehkonen, 1999). This is an important transformation, especially for human health, because it is the oxon form that is the active component of the pesticide. These degradates are very potent acetylcholinesterase inhibitors, a mode of action that can affect humans (Giesy et al. 1999). During the monitoring of supply reservoirs in the USA, the oxon degradate of malathion, malaoxon, was not detected in the raw water, while the parent compound was detected at 0.032µg L-1. Following water treatment, malathion was not detected in the finished drinking water but maloxon was detected at 0.106 µg L-1 (Nguyen et al, 2004). These oxon degradates of OP insecticides, such as diazoxon, are stable in water after their formation even following chlorination. The carbamate insecticide thiobencarb and its degradates formed following chlorination are degraded completely within 2 hours by the presence of chlorine in the water (Magara et al. 1994). The chlorination process can therefore both transform insecticides to stable active degradates and rapidly degrade them and their degradates. The herbicide isoxaflutole rapidly degrades to a stable phytotoxic degradate, diketonitrile, under environmental conditions. Chlorination of water containing diketonitrile rapidly degrades this compound to a nonbiologically active benzoic acid degradate (Lin et al. 2003). Using ozonation as a disinfection process instead of chlorination can also transform organic compounds present in the raw water. DEA, DIA, deisopropylatrazine amide, and 2- chloro-4,6-diamino-s-triazine have been identified as degradates formed from the major degradation pathway following the ozonation of water containing atrazine (Adams and Randtke, 1992). When atrazine undergoes advanced oxidation during the water treatment process, two degradates, not observed during environmental degradation, are formed, 2-chloro-4-ethylimino- 6-isopropylamino-s-triazine and 6-amino-2-chloro-4-ethylimino-s-triaizne (Acero et al. 2000). Two degradates of the insecticide aldicarb, aldicarb sulfoxide and aldicarb sulfone, can be removed during water treatment by reverse osmosis. The efficiency of removal of these compounds depends on the membrane composition used. However, when these degradates are present in raw water (groundwater) in the 11-47 µg L-1 concentration range, removal efficiency is in excess of 90% (Reported in USEPA, 2001).

The USEPA has set maximum contaminate levels (MCL) for three individual pesticide degradates, heptachlor epoxide, aldicarb sufone and aldicarb sulfoxide (Table 3.5). An MCL of 7 µg L-1 has been set for a combined concentration of aldicarb and its two degradates (USEPA, 2004). Current drinking water standards for pesticides in the EU are governed by the Drinking Water Directive (98/83/EC). There are no discrete pesticide or pesticide degradate drinking water quality standards set in the EU, however, concentrations of any pesticide and its “relevant metabolites” must not exceed 0.1 µg L-1, with a total pesticide concentration not exceeding 0.5 µg L-1 (EU, 1998). In Australia, the maximum acceptable concentration (MAC) for atrazine is set at 40 µg L-1. This concentration is set on the basis that DEA, DIA, diaminochlorotriazine and HA may constitute approximately 50% of the total atrazine-derived triazine compounds in environmental waters (NHMRC, 1996). Currently the health based guidelines for drinking water set by the World Health Organisation contain drinking water standards for pesticides. There is a combined pesticide and degradate guideline for DDT of 1µg L-1 (WHO, 2004). UK pesticide advised daily intake (ADI) data and mammalian toxicity data for pesticide degradates are provided in Appendix 5 and Appendix 6 respectively.

Table 3.5 Drinking water standards set for pesticide degradates

Region Compound Parent pesticide Standard Source (µg L-1)

Australia heptachlor and heptachlor epoxide 0.05 b NHMRC, 1996 Canada 2,3,4,6-tretrachlorophenol pentachlorophenol 100 c Health Canada, 1987 Canada 2,4,6-trichlorophenol pentachlorophenol 5 c Health Canada, 1987 Canada 2,4-dichlorophenol phenoxycarboxylic acid 900 c Health Canada, 1987 herbicides Canada aldicarb, aldicarb sulfone and aldicarb sulfoxide 9 c Health Canada, 1995 Canada atrazine and N-dealkylated metabolites 5 c Health Canada, 1993 Canada (Ontario) DDT and metabolites 30 Ontario, 2002 Canada (Ontario) heptachlor and heptachlor epoxide 3 Ontario, 2002 Canada (Ontario) total lindane 4 Ontario, 2002 EU pesticides and their relevant metabolites 0.1 EU, 1998 EU total pesticides 0.5 EU, 1998 USA aldicarb sulfone aldicarb 3 a USEPA, 2004 USA aldicarb sulfoxide albicarb 4 a USEPA, 2004 USA aldicarb, aldicarb sulfone and aldicarb sulfoxide 7 a USEPA, 2004 USA heptachlor epoxide heptachlor 0.2 a USEPA, 2004 World DDT and metabolites 1 b WHO, 2004

a - maximum contaminate level (MCL) b - guidance level c - maximum acceptable concentration (MAC)

PRIORITISATION OF DEGRADATES

INTRODUCTION

It is clear from the data presented in Chapters 2 and 3 that a large number of pesticides are in use and that these may be transformed into an even greater number of degradates. It will be impossible to investigate the impacts of all pesticides and all degradates on drinking water quality. There is therefore, a need to identify those degradates that have the greatest potential to reach drinking water supplies and those which are of greatest concern in terms of human health. In this Chapter, a simple prioritization approach to identify degradates of potential concern. The approach is a risk-based approach is presented that considers the usage of parent substances, the formation of degradates and their potential to be transported to surface waters and grounds as well as potential impacts on human health. It is important to recognize that the approach has been designed for ranking purposes only and a high risk index does not mean that a substance poses an unacceptable risk to human health. As long as usage data are available, the approach has can be applied across a range of scales including small catchments, states, and whole countries. In this project, the prioritization scheme was applied to the major usage pesticides in the USA and the UK. It is anticipated that the results of the prioritization exercise will be used to steer future research and monitoring programmes.

PRIORITIZATION APPROACH

Data selection

It is clear from Chapter 3 that a large body of data are available on the formation, properties, and occurrence of degradates in the environment. While limited data are available on the effects of degradates on human health, a significant quantity of data is available on the impacts of the parent compounds. To ensure the integrity of the prioritization results, the analyses should be based, where possible, on quality assessed data. During the registration process, industry-generated data is subject to extensive review by regulators and data that have been reviewed are presented in e.g., EPA and EU summary documents, and thus these documents can be good data sources and should therefore be used in preference to other published data.

Exposure

The potential for a degradate to reach drinking water supplies will be determined by a range of factors, most notably, the amount of parent pesticide used, the way in which the parent

©2008 AwwaRF. ALL RIGHTS RESERVED compound is used, the amount of a particular degradate formed, the mobility of the degradate, and its persistence. The potential for a degradate to enter drinking water is determined using data on each of these properties.

Risk characterization and ranking

The proposed has the form of RI, a risk index is derived from a degradate exposure index, E, and the ADI using Equation 4.1. By ranking the risk indices for each major degradate formed in a study system it is possible to identify those substances that pose the greatest risk to drinking water supplies. This information can then be used to steer future monitoring and research.

E RI = (4.1) ADI Where RI = Degradate risk index ADI = Acceptable daily intake (mg kg-1 body weight day-1)

It should be noted that this approach does not consider the formation of additional degradates created from either pesticides or environmental degradates during water treatment processes. The data availability was not sufficient to incorporate this component into the current prioritization approach. There may therefore be a requirement in the future to update this approach or develop an additional approach to include these ‘water treatment degradates’ when sufficient data becomes available.

Calculation of exposure index

The exposure index (E) is calculated using Equation 4.2, where E is a unitless value that reflects the amount of a degradate that could enter drinking water supplies relative to other degradates formed in the system being investigated.

E = A⋅ F ⋅ P (4.2)

Where E = Degradate exposure index A = Degradate amount index F = Fraction of degradate in the aqeous phase P = Persistence index

AMOUNT OF DEGRADATE FORMED

Information from usage surveys is initially used to identify the pesticides in use in the area of interest (this could be a country, a state or a catchment). Degradates from each pesticide parent are then identified from degradation route studies along with information on the amounts formed. It was recommended during the workshop organized during this study to develop the approach that only major metabolites (i.e. those performed in concentrations >10% of the parent)

U A = f (4.3) U max

Where A = Degradate amount index U = Amount of parent compound used (Kg yr-1) -1 Umax = Amount of highest usage pesticide used (Kg yr ) f = Fraction of degradate formed

SORPTION

Following release to the environment, the potential for a degradate to enter water bodies will be determined by its sorption to soils or sediments. The sorption behavior of a compound can be described by its sorption coefficient (Kd) or organic carbon normalized sorption coefficient (Koc). Tthe exposure assessment, the fraction of metabolite that is likely to be in the water component of the environment and which is therefore likely to enter drinking water supplies is determined using Equation 4.4.

1 F = (4.4) Kd +1 Where F = Fraction of degradate in the aqeous phase -3 -1 Kd = Sorption coeffient (cm g )

Typically, only Koc values will be available, if this is the case a total organic carbon content of 2% should be assumed to derive the Kd. The sorption of polar and ionizable compounds can be to clay minerals and metal oxides present in the soil. Therefore the prioritization will be conservative for such compounds if Koc data is used as the data input.

PERSISTENCE

The amount of a degradate entering a drinking water supply will also be determined by the persistence of the substance in the environment. This degradation index is determined using Equation 4.5. The equation assumes that degradation follows first order kinetics and calculates the fraction remaining after one year.

ln 2 .365 P = e − DT 50 (4.5)

Where P = Persistence index DT50 = Degradation half life for the degradate

The half life used in the calculations is determined by the way in which the parent compound is used. For degradates of pesticides that are applied to soils, the lowest half life from a degradation in soil study or a degradation in water study is used. For substances applied

Effects

Only limited data are available on the effects of degradates on human health. Therefore information on the potential health effects of the associated parent compound is used in the effects component of the prioritization exercise. Parent compounds are generally more toxic than degradates so the use of parent data is likely to be conservative. The most relevant toxicological endpoint for drinking water safety is the acceptable daily intake (ADI), ADI values are therefore used in the prioritization approach.

PRIORITISATION OF PESTICIDES IN USE IN THE USA AND UK

The prioritization procedure was applied to major pesticides in use in the USA and UK in order to illustrate the prioritization approach and to begin to identify degradates of potential concern to the water industry. For many degradates, insufficient data were available to fully prioritize the substance, in these instances conservative default values were assigned in order to enable an initial prioritization, these defaults were:

-3 -1 Kd - 0.02 cm g (i.e. Koc of 1 if soil organic carbon is 2%) DT50 - 1000 days Fraction - 1 ADI - lowest ADI in prioritization /10

The mobility, persistence and fraction formation default values were selected to represent the ‘worst-case’ scenario and to ensure that the inclusion of degradates in the approach whose dataset were incomplete was conservative in nature. A default Kd value of 0.02 (Koc = 1) classifies a compound, according to the SSLRC mobility classification (Hollis, 1991) as highly mobile. Similarly a persistence degradation rate of 1000 days would classify a compound as highly persistent according to the SSLRC persistence classification (Hollis, 1991). A default fraction value of 1 indicates that all of the applied pesticide would be degraded in the environment to the degradate, data in appendix 1 indicate that this very rarely happens so this value again can be considered as a worst-case estimate.

USA - Agricultural Pesticides

Pesticide usage data from the 1999 market estimates were used to prioritize those degradates that were likely to be formed in the US environment (Donaldson et al. 2002). Degradates of the 25 most widely used agricultural pesticides in the US were considered (Table 2.1)(Donaldson et al. 2002). For these 25 substances, eight had no environmental degradates identified. The three highest use pesticides without any relevant degradates data were metolachlor-s, propanil and chloropicrin. Fifty-six degradates were identified from the remaining eighteen pesticides. The degradates with a risk index of greater than 0.5 are provided in (Table 4.1). Appendix 8 provides a full index of all the prioritized degradates together with

©2008 AwwaRF. ALL RIGHTS RESERVED information concerning whether experimental regulatory data or default values were used during the prioritization. Application of the prioritization approach indicated that degradates of alachlor, cyanazine, acetochlor and atrazine are likely to be of most concern to US water supplies (Table 4.1).

©2008 AwwaRF. ALL RIGHTS RESERVED Table 4.1 The risk index for degradates from the US most used agricultural pesticides where the risk index is >0.5 (degradates were at least one default value was required in the prioritization are represented in italics)

Pesticide Degradate a Risk Index

alachlor 2,6-diethyl-N-methoxymethyl-2-sulpho-acetanilide 47.58 alachlor alachlor oxanilic acid 42.63 alachlor 2,6-diethyl-N-methoxy-methoxanilic acid 41.87 cyanazine cyanazine acid 35.95 alachlor alachlor ethane sulfonic acid 33.33 acetochlor 2-([N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)carbomyl]methylsulfonyl) acetic acid 33.30 acetochlor acetochlor oxanilic acid 33.30 acetochlor N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide 33.30 acetochlor N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide 33.30 cyanazine cynazine amide 32.62 alachlor alachlor DM-oxanilic acid 32.35 alachlor alachlor sulfinylacetic acid 30.83 alachlor 2',6'-diethyl-2-hydroxy-N-methoxymethylacetanilide 19.41 atrazine DEHA 13.96 atrazine deisopropyl atrazine 11.27 atrazine DIHA 9.90 atrazine diaminochloroatrazine 7.88 dichloropropene 3-chloroprop-2-enoic acid 7.61 dicamba 3,6-dichlorosalicylic acid 7.24 2,4-D 1,2,4-benzenetriol 6.28 atrazine hydroxy atrazine 2.51 malathion malathion dicarboxylic acid 2.43 metolachlor metolachlor oxanilic acid 2.23 chlorothalonil 3-cyano-2,4,5,6-tetrachlorobenzamide 1.69 trifluralin a,a,a-trifluoro-2,6-dinitro-N-propyl-p-toluidine 1.34 metolachlor CGA-37735 1.18 chlorothalonil 3-carbamyl-1,2,4,5-tetrachlorobezoic acid 0.99 trifluralin 2,2'-azoxybis (a,a,a-trifluoro-6-nitro-N-propyl-p-toluidine 0.88 trifluralin a,a,a-trifluoro-2,6-dinitro-p-cresol 0.79 trifluralin 2-ethyl-7-nitro-5-(trifluoromethyl) benzimidazole 0.76 chlorpyrifos 3,5,6-chloro-2-pyridinol 0.74 ethephon 2-hydroxy ethyl phosphonic acid 0.73 2,4-D 2,4-dichloroanisole 0.69 trifluralin a,a,a-trifluoro-5-nitro-4-propyl-toluene-3,4-diamine 0.61 chlorothalonil 3-cyano-6-hydroxy-2,4,5-trichlorobenzamide 0.60 chlorothalonil 3-carbamyl-2,4,5-trichlorobenzoic acid 0.60 glyphosate AMPA 0.52 trifluralin [2,6-dinitro-4-(trifluoromethyl)phenyl]propylamine 0.50

a - Appendix 7 contains IUPAC names for degradates represented by abbreviations

Pesticide usage data from the 1999 market estimates were used to prioritize those degradates that were likely to be formed in the US environment (Donaldson et al. 2002). Degradates of the 10 most used home and garden pesticides in the US were considered (Table 2.3)(Donaldson et al. 2002). For these 25 pesticides, five had no environmental degradates identified. The three highest use pesticides without any relevant degradates data were MCPP, dicamba and carbaryl. Thirteen degradates were identified from the remaining five pesticides. The risk index and information concerning whether experimental regulatory data or default values were used during the prioritization are provided in (Table 4.2). Application of the prioritization approach indicated that degradates of diazinon, chlorpyrifos and 2,4-D are likely to be of most concern to US water supplies. None of the identified degradates had full datasets available for use during the prioritization.

Table 4.2 The risk index and data availability for degradates from the US most used home and garden use pesticides (■ = experimental regulatory data available, □ = default value used in the prioritisation)

Pesticide Degradates Formation Kd DT50 ADI RI diazinon 6-hydroxy-2-isopropyl-4-methylpyrimidine ■ □ □ ■ 246.98 chlorpyrifos deethyl chlorpyrifos □ □ □ ■ 11.28 2,4-D 1,2,4-benzenetriol ■ □ □ ■ 4.83 chlorpyrifos 3,5,6-trichloro-2-pyridinol ■ ■ □ ■ 3.81 malathion malathion demethyl dicarboxylic acid ■ □ □ ■ 1.98 O-ethyl O-(3,5,6-trichloro-2-pyridinol) chlorpyrifos ■ □ □ ■ 1.47 phosphorothioate malathion diethyl mercaptosuccinate ■ □ □ ■ 1.17 malathion malathion demethyl monocarboxylic acids ■ □ □ ■ 1.07 malathion ethyl hydrogen fumarate ■ □ □ ■ 0.96 malathion malathion dicarboxylic acid ■ □ ■ ■ 0.69 glyphosate AMPA ■ ■ □ ■ 0.28 2,4-D 2,4-dichlorophenol ■ ■ □ ■ 0.22 malathion malathion monocarboxylic acids ■ □ ■ ■ <0.01

USA - Industrial/Commercial/Government Use Pesticides

©2008 AwwaRF. ALL RIGHTS RESERVED Application of the prioritization approach indicated that degradates of diuron, triclopyr, chlorpyrifos and 2,4-D are likely to be of most concern to US water supplies. None of the identified degradates had full datasets available for use during the prioritization.

©2008 AwwaRF. ALL RIGHTS RESERVED Table 4.3 The risk index and data availability for degradates from the US most used Industrial/Commercial/Government use pesticides (■ = experimental regulatory data available, □ = default value used in the prioritisation)

Pesticide Degradates Formation Kd DT50 ADI RI

diuron N'-(3,4-dichlorophenyl)-N-methylurea □ □ □ ■ 25.37 5-chloro-3,6-dihydroxy-2-pyridinoloxyacetic triclopyr ■ □ □ ■ 10.96 acid chlorpyrifos deethyl chlorpyrifos □ □ □ ■ 6.34 diuron N'-(3-chlorophenyl)-N,N-dimethylurea ■ □ □ ■ 6.34 2,4-D 1,2,4-benzenetriol ■ □ □ ■ 4.83 triclopyr 3,5,6-trichloro-2-pyridinol ■ ■ □ ■ 3.81 triclopyr oxamic acid ■ □ □ ■ 3.65 5-cyano-4,6,7-tichloro2H-1,2-benzisothiazol-3- chlorothalonil ■ □ □ ■ 2.61 one diuron 3-chlorophenyl methylurea ■ □ □ ■ 2.54 diuron phenyl-1,1-dimethylurea ■ □ □ ■ 2.54 diuron N'-(3-chlorophenyl)-N-methyl urea ■ □ □ ■ 2.54 chlorpyrifos 3,5,6-trichloro-2-pyridinol ■ ■ □ ■ 2.14 chlorothalonil SDS-67042 sulphoxide ■ □ □ ■ 1.40 malathion malathion demethyl dicarboxylic acid ■ □ □ ■ 0.89 2,5,6-trichloro-4-(glutathione-5- chlorothalonil ■ □ □ ■ 0.85 yl)isophthalonitrile chlorothalonil 2,5,6-trichloro-4-(thio)isophthalonitrile ■ □ □ ■ 0.85 O-ethyl O-(3,5,6-trichloro-2-pyridinol) chlorpyrifos ■ □ □ ■ 0.82 phosphorothioate chlorothalonil 3-cyano-2,4,5,6-tetrachlorobenzamide ■ □ □ ■ 0.59 chlorothalonil 4-hydroxy-2,5,6-trichloroisophthalonitrile ■ ■ □ ■ 0.57 malathion diethyl mercaptosuccinate ■ □ □ ■ 0.53 malathion malathion demethyl monocarboxylic acids ■ □ □ ■ 0.48 malathion ethyl hydrogen fumarate ■ □ □ ■ 0.43 chlorothalonil 3-cyano-6-hydroxy-2,4,5-trichlorobenzamide ■ □ □ ■ 0.34 malathion malathion dicarboxylic acid ■ □ ■ ■ 0.31 glyphosate AMPA ■ ■ □ ■ 0.22 2,4-D 2,4-dichlorophenol ■ ■ □ ■ 0.22 pendimethalin 2,6-dinitro-3,4-dimethyl aniline ■ □ □ ■ 0.14 diuron 3,4-dichloroaniline ■ □ □ ■ 0.13 chlorothalonil 3-carbamyl-2,4,5-trichlorobenzoic acid ■ ■ □ ■ 0.10 malathion malathion monocarboxylic acids ■ □ ■ ■ <0.01

In order to prioritize degradates that are likely to be formed in the UK environment, pesticide usage data for the UK was generated by combining data presented in the most recent pesticide usage reports produced by the Central Science Laboratory for various market sectors, e.g., arable, outdoor vegetables and fodder crops (Garthwaite et al. 1999; Dean et al. 2001; Garthwaite et al. 2001a; Garthwaite et al. 2001b; Hutson et al. 2001; Garthwaite and Thomas,

©2008 AwwaRF. ALL RIGHTS RESERVED 2003a; Garthwaite and Thomas, 2003b; Garthwaite et al. 2003; Stoddart et al. 2003). Fifty-four pesticides were identified as representing 90% of all pesticide use in the agricultural sector in the UK, of these, 18 either had no data available to identify their degradation pathway or identify whether they had environmental degradates. The three highest use pesticides without any relevant degradates data were chlormequat, MCPP and tri-allate. One hundred and eleven degradates were identified from the remaining 36 pesticides and these substances were run through the prioritization system. The degradates with a risk index of greater than 0.5 are provided in (Table 4.4). Table 4.4 The risk index for degradates from the UK most used agricultural pesticides where the risk index is >0.5 (degradates were at least one default value was required in the prioritization are represented in italics) Pesticide Degradate a Risk Index

cyanazine cyanazine acid 26.56 cyanazine cynazine amide 24.11 isoproturon 1-methyl-3-(4-isopropyl phenyl)-urea 7.92 flufenacet FOE sulfonic acid 4.67 bitertanol/tebuconazole 1,2,4-triazole 4.51 flufenacet FOE oxalate 3.25 dicamba 3,6-dichlorosalicylic acid 3.15 atrazine/simazine deisopropylatrazine 2.12 flufenacet FOE methyl sulfone 2.03 flufenacet FOE thioglycolate sulfoxide 2.03 flufenacet thiadone 2.03 metaldehyde acetaldehyde 1.63 bitertanol bitertanol benzoic acid 1.59 atrazine DEHA 1.29 propachlor propachlor oxanilic acid 1.26 atrazine/simazine DIHA 1.21 trifluralin α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine 1.10 isoproturon 3-[4-(2’-hydroxy-2’-propyl)-phenyl]-methyl urea 1.01 bitertanol 4-hydroxybiphenyl 1.00 linuron demethyl linuron 0.99 atrazine/simazine diaminochloroatrazine 0.89 dimethoate O-desmethyl dimethoate 0.81 propachlor propachlor ethane sulfonic acid 0.72 trifluralin 2,2’-azoxybis (α,α,α-trifluoro-6-nitro-N-propyl-p-toluidine 0.72 2-chloroethylphosphonic acid ethylene 0.67 trifluralin α,α,α-trifluoro-2,6-dinitro-p-cresol 0.65 trifluralin 2-ethyl-7-nitro-5-(trifluoromethyl) benzimidazole 0.62 asulam ionic form of asulam 0.61 chlorothanonil 3-cyano-2,4,5,6-tetrachlorobenzamide 0.61 chlorothanonil 3-carbamyl-2,4,5-trichlorobenzoic acid 0.60 metalaxyl CGA-62826 0.57 chloridazon 5-amino-4-chloropyridazine-3(2H)-one 0.54 metalaxyl 2-N-(2,6-dimethylphenyl)-2-methoxyacetylamino propanoic acid 0.53 trifluralin α,α,α-trifluoro-5-nitro-4-propyl-toluene-3,4-diamine 0.50 mecoprop-P 4-chloro-2-methyl phenol 0.50 a – Appendix 7 contains IUPAC names for degradates represented by abbreviations

©2008 AwwaRF. ALL RIGHTS RESERVED Appendix 9 provides a full index of all the prioritized degradates together with information concerning whether experimental regulatory data or default values where used during the prioritization. Application of the prioritization approach indicated that degradates of cyanazine, isoproturon and flufenacet are likely to be of most concern to US water supplies (Table 4.4). A few degradates were produced by more than one degradate, therefore following the prioritization of the risk index for these compounds was added so that the degradate has a single entry and the priority would reflect the overall risk of the compound.

Sample calculation of the risk index

To assist in the use of this prioritization approach a sample calculation of the risk index for one compound is provided below. Hydroxyatrazine is the highest degradate with no default data points in both the UK and US prioritization. Therefore this compound was selected for the sample calculation (using atrazine US usage data):

Available regulatory data for hydroxyatrazine U = 36287391 kg yr-1 (atrazine usage) -1 Umax = 36287391 kg yr (atrazine highest use pesticide in US in 1999) f = 0.19 Kd - 1.7 DT50 - 164 days ADI - 0.006 mg kg-1 body weight day-1

Calculation of amount index (A)

36287391 A = 0.19 = 0.19 36287391

Calculation of fraction of degradate in the water column (F)

1 F = = 0.37 1.7 +1

Calculation of persistence index (P)

ln 2 .365 P = e−164 = 0.21

Caluclation of exposure index (E)

E = 0.19*0.37*0.21= 0.015

Calculation of the overall risk index (RI) 0.015 RI = = 2.5 0.006

When undertaking a prioritization for an area of interest, it is the collection and collation of relevant degradate data that is the most time consuming phase of the whole process. The staring point to any prioritization is the definition of the system i.e. catchment, watershed, country etc. The pesticide usage data collected for the system will define the scope of the prioritization and a data collection phase can then get underway focusing on the pesticides used within that system. Once a prioritization has been completed for a system it should be regularly reviewed so that any new data, either pesticide usage or degradate formation and property data, that has become available since the last prioritization is included. This is important if there is a dramatic shift in pesticide usage patterns e.g. the banning of one pesticide and the resulting wide scale use of another. Therefore at a minimum the pesticide usage component of a prioritization should be updated when new data becomes available, which is generally annually. The first implementation of a prioritization for a system will be the most labour intensive phase, subsequent revisions should require significantly less resources. The implementation of a prioritization will allow resources e.g. monitoring and treatment to be focused towards those degradates of most concern. However the prioritization approach also has a number of limitations which include:

• The prioritization focuses on non-point source pollution from pesticides, point source pollution e.g. spills, will not be identified; • Any prioritization is only as reliable as the data used to carry it out. Currently there are a number of pesticides and their degradates without any suitable experimental regulatory data; • Each prioritization focuses on pesticide usage data from an individual year, the inputs from persistent pesticides and/or degradates from previous years are not accounted for in the priority scheme; and • The approach does not provide any characterization of the risks posed by degradates formed as part of the water treatment process.

CONCLUSIONS AND FUTURE RESEARCH

CONCLUSIONS

Pesticide degradates are formed in the environment following the biotic and abiotic degradation of pesticides. To date a number of pesticide degradates have been detected in the environment, with 50 detected in soil, 29 detected in groundwater and 26 detected in surface waters. Therefore, the potential for these compounds to enter water sources used for abstraction is high. The frequency at which these compounds are detected as well as their peak and mean concentrations vary greatly depending on the water body monitored. Higher concentrations are often observed at water sources closer to the site of application. The concentration of degradates can decrease by at least one or two orders of magnitude from surface runoff to the subsequent streams and rivers (e.g., deethyatrazine). However, sometimes peak concentrations of degradates detected in surface waters are less than the parent compound, the total loss over the same period can be greater. The presence of pesticide degradates in drinking water will depend on numerous factors including physico-chemical properties, pesticide usage, pesticide application scenario, degradate formation, degradate and pesticide biotic and abiotic degradation rates and elimination rates, during water treatment. A number (122) of degradates have been observed in degradation studies at >10% of the applied parent pesticide while >70% have slower degradation rates than the parent compound. Therefore, there is the potential for these compounds to remain in the environment. With 50% of the available sorption data for degradates indicating that their mobility can be classified as mobile to very mobile, then there is obviously a great deal of potential for these compounds to enter surface waters and groundwaters at levels that could be of concern to the water industry. In this study, the approach has been applied to degradates that are likely to be formed in the US and UK agricultural environments. Using this approach degradates of alachlor, acetochlor, cyanazine, atrazine, dichloropropene, dicamba, 2,4-D, chlorpyrifos, chlorothalonil, flufenacet, isoproturon, simazine and propyzamide have been identified as being the highest priority. Due to a large number of data gaps, these assessments were based on a significant number of default values. However, most of the data required will have been developed by pesticide companies during the registration process. In the near future therefore it would be beneficial for the water industry and the pesticide manufacturers to work together to fill these gaps and to develop a final prioritization list. Substances that then appear at the top of the list should be the focus of any future work in these agricultural systems.

FUTURE RESEARCH

Once the most likely pesticides and degradates to be present in raw water are identified via a prioritization approach (Chapter 4), further studies will be required. The final session of the workshop was directed at identifying information and research needs specifically relating to

©2008 AwwaRF. ALL RIGHTS RESERVED drinking water utilities. Four key areas were identified (i) information management, (ii) analysis, (iii) monitoring and (iv) treatment. Treatment issues included studies into the fate of compounds in conventional and advanced treatment processes and also the likely transformation of compounds during treatment.

Identified research priorities: 1. Occurrence study of pesticide degradates was identified as the highest priority. The list of priority pesticides and degradates produced from the workshop’s prioritization scheme should be monitored for occurrence (in selected watersheds and treatment works) to determine their levels in drinking water supplies and ‘test’ the prioritization scheme. This is particularly true for compounds that are identified for which the USGS and other agencies have not previously searched. Previous studies, including AWWA’s atrazine degradate study and USGS monitoring could serve as a starting point. 2. A significant proportion of the workshop discussion focused on availability of information required to run the prioritization scheme. It was found that different agencies possess valuable information for water utilities on toxicological effects, analytical methods, physical properties, treatment effects, and occurrence levels. Some information is considered proprietary, while other information is difficult to find. It would be helpful to initiate a synthesis of available resources as well as a database of information relevant to pesticides, degradates, and adjuvants beyond the scope of the aforementioned workshop. This information would allow future users of the prioritization scheme to assess implications at a local level and for specific parent compounds. 3. There is a need for analytical methods to be developed for degradates of interest to help support occurrence and treatability studies. 4. The fate of parent and degradate compounds in water treatment processes was identified as a knowledge gap and two approaches to screen compounds were identified. The first is to use physiochemical information on identified compounds and relate these to treatment categories. The second approach is laboratory based treatability assessments on individual compounds or groups of compounds. For both approaches specific interest should be paid to the effect of oxidation processes such as chlorine, chloramination, ozone, and advanced oxidation processes. 5. During the treatment of drinking water, it is possible for additional compounds, “water treatment degradates”, to be formed from pesticides and their environmental degradates present in the drinking water especially oxidation and disinfection processes. Therefore it is important to identity the most likely transformation pathways to occur during water treatment and identify these additional compounds. The identification of these compounds was not a component of this study and needs further investigation. 6. Given the relative percentages of adjuvants used in pesticides versus other products, it makes sense to include all sources in adjuvant studies, not just pesticides. Investigation of relative source contributions to adjuvant levels in source waters and their fate in drinking water treatment processes could help shed light on the issue.

RELEVANCE FOR UTILITIES

One of the major water treatment process improvements in recent years has been the ability to remove to very low levels a wide variety of pesticides. Monitoring and process development research has primarily focused on the parent compounds and there is little information available on the levels or fate of pesticide degradates and as yet there are few regulatory limits on individual pesticide degradates. This project has shown that a wide range of pesticide degradates have been detected in both groundwater and surface waters, and hence there is potential for these compounds to enter water sources used for water supply. This report can be used a reference source of pesticide usage and reported degradates, but it can also be used to develop prioritization schemes for utilities interested in monitoring and removing degradates. The prioritization scheme developed here can be applied across a range of scales from the catchment scale to the international scale and can be used to produce ranking lists for individual water treatment works. These ranking lists can then be used to support monitoring programmes and treatability studies. For example, the prioritization scheme has been used here to identify those substances that pose the greatest risk to drinking water supplies on a country wide level. It has identified the degradates of alachlor, acetochlor, cyanazine, atrazine, dichloropropene, dicamba and 2-4-D as likely to be of most concern to US water supplies whilst, in the UK, degradates of cyanazine, isoproturon and flufenacet were ranked highest and should be selected first for monitoring and treatability studies. Using the prioritization scheme on a state or catchment level will produce a more focused ranking for identifying monitoring and treatability needs. The project and the workshop identified knowledge gaps and resulting research needs, some of which may be suited for AwwaRF funding but others of which may be more suitable to organizations such the U.S. Environmental Protection Agency, U.S. Geological Survey and Global Water Research Coalition (GWRC). The identified needs were grouped into six major priorities and will help extend the usefulness of the prioritization scheme and our overall knowledge on the analysis, occurrence and fate of pesticide degradates.

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) 2,4-dichlorophenol 2,4-D 3 ± 1% 8 days Canada Smith and Aubin, 1991 11% - - Reported in Roberts, 1998 trace 14 days - Reported in PSD 68 2-5% 10 days - Reported in PSD 68 2,4-dichloroanisole 2,4-D 10 ± 1% 16 days Canada Smith and Aubin, 1991 2-5% 10 days - Reported in PSD 68 acetochlor oxanilic acid acetochlor > 10% - - Reported in Roberts, 1998 ©2008 AwwaRF. ALLRIGHTS RESERVED 2-([N-(ethoxymethyl)-N-(2-ethyl-6- acetochlor > 10% - - Reported in Roberts, 1998 methylphenyl)carbomyl]methylsulfonyl) acetic acid N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-2- acetochlor > 10% - - Reported in Roberts, 1998 sulfoneacetamide N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide acetochlor > 10% - - Reported in Roberts, 1998 2,6-diethyl-N-methoxy-methoxanilic acid alachlor 13 - 22% 4 - 7 weeks - Reported in PSD 22 2,6-diethyl-N-methoxymethyl-2-sulpho- alachlor 15 - 25% 4 - 7 weeks - Reported in PSD 22 55 acetanilide alachlor ethane sulfonic acid alachlor 20% 9 days USA Aga and Thurman, 2001 HOE 101630 amidosulfuron 7% 3 days - Reported in PSD 1994a 5.2% 14 days - Reported in PSD 1994a 49.6% 7 days - Reported in PSD 1994a 40.4% 49 days - Reported in PSD 1994a 21% 49 days - Reported in PSD 1994a 2-amino-4,6-dihydroxypyrimidine amidosulfuron 30% 49 days - Reported in PSD 1994a dihydroxy anilazine anilazine 19.2% 72 hours USA Reported in PSD 1994c 43% 366 days USA Reported in PSD 1994c 21% 46 hours USA Reported in PSD 1994c 0.5% - - Reported in PSD 1994c 9 - 12% 3 - 112 days - Reported in PSD 1994c 13.2% 111 days - Reported in PSD 1994c 4.6% 0 days - Reported in PSD 1994c 6.8% (sterile) 28 days - Reported in PSD 1994c 15.7% 2 days - Reported in PSD 1994c dihydroxy anilazine continued anilazine 7% 100 days - Reported in PSD 1994c hydroxyatrazine atrazine 19% 95 days USA Assaf and Turco, 1994 0.7% 62 days - Reported in Solomon et al. 1996 deethylatrazine atrazine 12.4% 142 days USA Assaf and Turco, 1994 4.18% 244 days - Reported in Solomon et al. 1996 deisopropylatrazine atrazine 10.1% 95 days USA Assaf and Turco, 1994

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) 1.61% 244 days - Reported in Solomon et al. 1996 diaminochloroatrazine atrazine 6.7% 95 days USA Assaf and Turco, 1994 0.7% 3 days - Reported in Solomon et al. 1996 DEHA atrazine 11% 250 days USA Assaf and Turco, 1994 DIHA atrazine 7.8% 250 days USA Assaf and Turco, 1994 azoxystrobin acid azoxystrobin 20% - - Reported in Roberts and Hutson, 1999 carbofuran benfuracarb 73 - 93% 0 days - Reported in PSD 5 bitertanol benzoic acid bitertanol 19% 30 days - Reported in Roberts and

©2008 AwwaRF. ALLRIGHTS RESERVED Hutson, 1999 8.6% 29 days - Reported in PSD 92 bitertanol ketone bitertanol < 2% - - Reported in Roberts and Hutson, 1999 p-hydroxy buprofezin buprofezin < 3% 150 days - Reported in PSD 1993i buprofezin sulphoxide buprofezin < 3% 150 days - Reported in PSD 1993i buprofezin metabolite 9 buprofezin < 3% 150 days - Reported in PSD 1993i 1-tert-butyl-3-isopropyl-5-phenyl-2-biuret buprofezin < 3% 150 days - Reported in PSD 1993i

56 1-isopropyl-3-phenyl urea buprofezin < 3% 150 days - Reported in PSD 1993i 5-amino-4-chloropyridazin-3(2H)-one chloridazon 46.6% 187 days Reported in Roberts, 1998 5-amino-4-chloro-2-methyl-2-hydropyridazin-3- chloridazon 1.3% 187 days Reported in Roberts, 1998 one 3-carbamyl-2,4,5-trichlorobenzoic acid chlorothalonil 25% 56 days Brazil Regitano et al. 2001

4-hydroxy-2,5,6-tetrachloroisophthalonitrile chlorothalonil < 10% 0 - 14 days Brazil Regitano et al. 2001 3-cyano-2,4,5,6-tetrachlorobenzamide chlorothalonil < 10% 0- 14 days Brazil Regitano et al. 2001 3,5,6-chloro-2-pyridinol chlorpyrifos 29% 24 months Australia Baskaran et al. 1999 3,5,6-chloro-2-pyridinol chlorpyrifos 18.5% 21 days Australia Baskaran et al. 2003 desethyl chlorfenvinphos chorfenvinphos < 7% 4 months - Reported in PSD 1994k 2,4-dichlorophenyl)-ethan-1,2-diol chorfenvinphos < 7% 4 months - Reported in PSD 1994k 1-(2,4-dichloroheny etha-1-ol chorfenvinphos < 7% 4 months - Reported in PSD 1994k 2,4-dichloroacetophenone chorfenvinphos < 7% 4 months - Reported in PSD 1994k 2,4-dichlorophenyl chloride chorfenvinphos < 7% 4 months - Reported in PSD 1994k 2,4-dichlorophenyloxrane chorfenvinphos < 7% 4 months - Reported in PSD 1994k salts or conjugates desethyl chlorfenvinphos chorfenvinphos < 7% 4 months - Reported in PSD 1994k 2-chlorobenzene sulfonamide chlorsulfuron 50% 2 months - Reported in PSD 1991c T2SO cycloxydim 39% 7 days - Reported in PSD 1990e T2SO2 cycloxydim 3 - 4% 21 days - Reported in PSD 1990e T2SO cycloxydim 48% 7 days - Reported in PSD 1990e T2SO2 cycloxydim 10% 21 days - Reported in PSD 1990e TSO2 cycloxydim 7% 43 days - Reported in PSD 1990e T1SO cycloxydim 3% 21 days - Reported in PSD 1990e T1S cycloxydim 3% 1 days - Reported in PSD 1990e CCA cypermethrin 0.2-0.4% - Germany Class, 1992

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) 3-phenoxybenzoic acid cypermethrin 0.2-0.4% - Germany Class, 1992 3-phenoxybenzaldehyde cypermethrin 0.2-0.4% - Germany Class, 1992 melamine cyromazine 32% 30 days USA Reported in PSD 1993l ~70% 2 - 3 weeks Switzerland Reported in PSD 1993l 20 - 44% 29 weeks - Reported in PSD 1993l 41% 27 weeks - Reported in PSD 1993l ethyl-m-hydroxyphenyl carbamate desmedipham 16% 7 days Germany Reported in PSD 1993f 4.5% 14 days Germany Reported in PSD 1993f pyrimidinol diazinon 72.9% 14 days - Reported in PSD 1991b 2% 3 weeks - Reported in PSD 1991b 8% (sterile) 3 weeks Reported in PSD 1991b

©2008 AwwaRF. ALLRIGHTS RESERVED hydroxyl-pyrimidinol diazinon 1.5% 166 days - Reported in PSD 1991b 3,6-dichlorosalicylic acid dicamba 28% 5 weeks Canada Smith, 1973 3,6-dichlorosalicylic acid dicamba 31% 6 weeks Canada Smith, 1974 diclofop acid diclofop-methyl 80 - 87% 1 day - Reported in PSD 1991e 77% 8 days - Reported in PSD 1991e 90% 2 days - Reported in PSD 1991e 4-(2,4-dichlorophenoxy)phenol diclofop-methyl 0.7 - 3% 16 days - Reported in PSD 1991e trace 14 days Canada Reported in PSD 1991e

57 1 - 10% - Germany Reported in PSD 1991e 11% 8 days - Reported in PSD 1991e 2.5% 6 days - Reported in PSD 1991e N-demethyldimefuron dimefuron 16.6 - 29.98% 93 days - Reported in PSD 1993h compound B dimefuron 0.5 - 2.2% 92 days - Reported in PSD 1993h compound C dimefuron ND - 2.23% 92 days - Reported in PSD 1993h compound D dimefuron 0.32 - 2.8% 92 days - Reported in PSD 1993h O-desmethyldimethoate dimethoate 2.1% - - Reported in PSD 1993j O,O-dimethylphosphorothioic acid dimethoate 1% - - Reported in PSD 1993j omethoate dimethoate 6% 2 weeks - Reported in PSD 1993j 3-desmethyl dimethomorph and 4-desmethyl dimethomorph <0.5% - - Reported in PSD 1994g dimethomorph combined dintro octyl phenol dinocap 5.5% 30 days Germany Reported in PSD 1991a desphenyl-fenvalerate esfenvalerate 0.9 - 6.4% 12 weeks Japan Reported in PSD 1992b CONH2-fen esfenvalerate 1.5% 180 days Japan Reported in PSD 1992b 32% 12 months USA Reported in PSD 1992b 1 - 4% 30 days - Reported in PSD 1992b 4’-OH-fen esfenvalerate 1.3% 14 days Japan Reported in PSD 1992b 3% 1 month USA Reported in PSD 1992b 1 - 4% 30 days - Reported in PSD 1992b 3-benzylbenzoic acid esfenvalerate 1.4% 14 days Japan Reported in PSD 1992b Cl-Vacid esfenvalerate 3% 12 months USA Reported in PSD 1992b 1 - 4% 30 days - Reported in PSD 1992b SD 50365 esfenvalerate 1% 3 months USA Reported in PSD 1992b 1 - 4% 30 days - Reported in PSD 1992b RH-6467 fenbuconazole <10% - Reported in PSD 1995c

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) RH-6467 continued fenbuconazole <7.9% - - Reported in PSD 1995c RH-9129 fenbuconazole <10% - - Reported in PSD 1995c RH-9130 fenbuconazole <4.5% - - Reported in PSD 1995c 4-(6-chloro-2-benzoxazolyloxy)phenol fenoxaprop-p-ethyl <3% - - Reported in PSD 1990a α-carbomoyl-3-phenoxybenzyl-2,2,3,3- fenpropathrin 14% - UK Reported in PSD 1989b tetramethyl cyclopropane carboxylate and α- carboxy-3-phenoxybenzyl-2,2,3,3-tetramethyl cyclopropane carboxylate combined 7% 8 weeks - Reported in PSD 1989b α-carboxy-3-phenoxybenzyl-2,2,3,3-tetramethyl fenpropathrin 0.3% 26 weeks - Reported in PSD 1989b cyclopropane carboxylate

©2008 AwwaRF. ALLRIGHTS RESERVED 3-phenoxybenzoic acid fenpropathrin 14% - UK Reported in PSD 1989b 0.6% 160 days - Reported in PSD 1989b 2,2,3,3-tetramethyl cyclopropane carboxylic acid fenpropathrin 7% 8 weeks - Reported in PSD 1989b <0.1% 60 days - Reported in PSD 1989b R0 18-5445 fenpropidin 1 – 5% - - Reported in PSD 1993b R0 12-7124 fenpropidin 1 – 5% - - Reported in PSD 1993b M3 fenpyroximate 2.6 - 10.8% 14 - 28 days Japan Reported in PSD 1995d 4.9 - 7.9% 16 - 32 days Germany Reported in PSD 1995d 58 1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile fenpyroximate 8.2 - 8.8% 28 days Japan Reported in PSD 1995d compound VII fluazinam 2.5% 90 days UK Reported in PSD 1994h <2% - - Reported in PSD 1994h compound VIII fluazinam 1.5% 30 days UK Reported in PSD 1994h <2% - - Reported in PSD 1994h compound XII fluazinam 11.4% 30 days UK Reported in PSD 1994h 7% - - Reported in PSD 1994h fluzifop acid fluzifop-P-butyl 97% 2 days - Reported in PSD 1988a 5-trifluoromethyl-2-pyridone and 2-(4- fluzifop-P-butyl 50% 2 - 12 weeks - Reported in PSD 1988a hydroxyphenoxy)-5-trifluoromethyl pyridine combined RH-5781 fluoroglycofen-ethyl 79% 21 days - Reported in PSD 1992a RH-9985 fluoroglycofen-ethyl 8.1% - - Reported in PSD 1992a RH-5349 fluoroglycofen-ethyl 6% 51 days - Reported in PSD 1992a bis (4-fluorophenyl)methyl silanol flusilazole 4 - 5% 52 weeks - Reported in PSD 1989a fomesafen amino acid fomesafen 10.2% 88 days UK Reported in PSD 1995a fomesafen amine fomesafen 20.5% 59 days UK Reported in PSD 1995a fomesafen nitro acid fomesafen <1% - UK Reported in PSD 1995a HOE 35956 glufosinate 25 - 53% 35 days Germany Reported in PSD 1990f ammonium 3-methyl phosphinico-proprionic acid glufosinate 35% 96 days USA Reported in PSD 1990f ammonium 52% 95 days - Reported in PSD 1990f 32% 16 days Germany Reported in PSD 1990f 15 - 47% 7 - 14 days - Reported in PSD 1990f 31% 37 days USA Reported in PSD 1990f

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) HOE 64619 glufosinate 18% 95 days - Reported in PSD 1990f ammonium 15% 16 days Germany Reported in PSD 1990f 26% 14 days - Reported in PSD 1990f HOE 64619 f 3-methyl 8% 16 days - Reported in PSD 1990f phosphinico- proprionic acid 31 - 38% 21 days - Reported in PSD 1990f HOE 65594 glufosinate 8% 8 days - Reported in PSD 1990f ammonium 5% - Reported in PSD 1990f

©2008 AwwaRF. ALLRIGHTS RESERVED HOE 86486 glufosinate 5% 95 days - Reported in PSD 1990f ammonium 2% 16 days Germany Reported in PSD 1990f HOE 85355 glufosinate 34% 0 days - Reported in PSD 1990f ammonium HOE 83348 HOE 070542 4.5% 8 days - Reported in PSD 1990c 20% 97 days - Reported in PSD 1990c HOE 88988 HOE 070542 1.5% 8 days - Reported in PSD 1990c

59 HOE 88989 HOE 070542 14.2% 8 days - Reported in PSD 1990c HOE 72829 HOE 070542 2.1% 8 days - Reported in PSD 1990c 36% 2 days - Reported in PSD 1990c HOE 87606 HOE 070542 1% 8 days - Reported in PSD 1990c HOE 87607 HOE 070542 11% - - Reported in PSD 1990c HOE 89628 HOE 070542 7% 97 days - Reported in PSD 1990c 1,5-bis(-p-tolyl)-1,4-pentadiene-3-one hydramethylnon 25.9% 3 months - Reported in PSD 1994i M1 imazaquin 7.6% 12 months - Reported in PSD 1993a 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro-2-imino- imidacloprid <1.8% 100 days - Reported in PSD 1993e 2,3-dihydro-imidazole and 1-(6-chloro-pyridine- 3-ylmethyl) imidazolidine-2,4-dione combined 1-(6-chloro-pyridine-3-ylmethyl)-N-nitroso-2- imidacloprid <1.8% 100 days - Reported in PSD 1993e imino-imidazolidine <3% - - Reported in PSD 1993e <2% - - Reported in PSD 1993e 1-(6-chloro-pyridine-3-ylmethyl)-2-imino- imidacloprid <1.8% 100 days - Reported in PSD 1993e imidazolidine 4.3% - - Reported in PSD 1993e <2% - - Reported in PSD 1993e 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro imidacloprid <1.8% 100 days - Reported in PSD 1993e guanidine and 3-(6-chloro-pyridine-3-ylmethyl) imidazolidine-2,5-dione 6-chloro-nicotinic acid imidacloprid <1.8% 100 days - Reported in PSD 1993e <3% - - Reported in PSD 1993e 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro imidacloprid <3% - - Reported in PSD 1993e guanidine

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) 3.4% - - Reported in PSD 1993e 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro-2-imino- imidacloprid <3% - - Reported in PSD 1993e imidazollidine-5-ol propargyl butyl carbamate IPBC >90% 6 hours - Reported in PSD 1994n kresoxim-methyl acid kresoxim-methyl 43% 180 days - Reported in Roberts and Hutson, 1999 malaoxon malathion 1.4% < 7 days - Reported in Roberts and Hutson, 1999 malathion dicarboxylic acid malathion 62% 7 days - Reported in Roberts and Hutson, 1999 4-chloro-2-methyl phenol mecoprop-P 2 - 3% 20 days - Reported in PSD 1994e

©2008 AwwaRF. ALLRIGHTS RESERVED 2-N-(2,6-dimethylphenyl)-2-methoxyacetylamino metalaxyl 50% 21 days - Reported in Roberts and propanoic acid Hutson, 1999 metloachlor ethane sulfonic acid metolachlor 5% 14 days USA Aga and Thurman, 2001 carbinol metolachlor 24.3% 120 days USA Rice et al. 2002 morpholinone metolachlor 2.9% 120 days USA Rice et al. 2002 2-(aminosulfonyl) benzoic acid metsulfuron-methyl 16% 24 weeks USA Reported in PSD 1991d 19% (sterile) - USA Reported in PSD 1991d 8 - 29% 8 weeks USA Reported in PSD 1991d

60 saccharin metsulfuron-methyl 32% 16 weeks USA Reported in PSD 1991d 4 - 7% (sterile) - USA Reported in PSD 1991d 16 - 32% 2 - 4 weeks USA Reported in PSD 1991d methyl-2-(aminosulfonyl)benzoate metsulfuron-methyl 2 - 14% - USA Reported in PSD 1991d 38 - 51% (sterile) 24 weeks USA Reported in PSD 1991d 6 - 9% 2 weeks USA Reported in PSD 1991d 2-(3,5-dichlorophenyl)-4,4-dimethyl-5- propyzamide 9% - - Reported in Roberts, 1998 methyleneoxazoline N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide propyzamide 77% - - Reported in Roberts, 1998 [2-(3,5-dichlorophenyl)-4,4-dimethyl-1,3- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 oxazolin-5-ylidene]methan-1-ol (3,5-dichlorophenyl)-N-(3-hydroxy-1,1-dimethyl- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 2-oxopropyl)carboxamide (3,5-dichlorophenyl)-N-(3-hydroxy-1,1- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 dimethylpropyl)carboxamide (3,5-dichlorophenyl)-N-(2,3-dihydroxy-1,1- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 dimethylpropyl)carboxamide 3-[(3,5-dichlorophenyl)carbonylamino]-3- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 methylbutanoic acid 2-[(3,5-dichlorophenyl)carbonylamino]-2- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 methylpropanoic acid 3-[(3,5-dichlorophenyl)carbonylamino]-3-methyl- propyzamide 0.1 -1.6% - - Reported in Roberts, 1998 2-oxobutanoic acid deethylterbuthylazine terbuthylazine < 5% - - Reported in Roberts, 1998 2,6-dinitro-4-(trifluoromethylphenyl)amine trifluralin 0.2% - - Reported in Roberts, 1998

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) [2,6-dinitro-4- trifluralin 1.7% 1 year - Reported in Roberts, 1998 (trifluoromethyl)phenyl]propylamine hydroxyatrazine atrazine 39.1 ± 9.1% 6 months USA Sorenson et al. 1993 deethylatrazine atrazine 33 ± 3.8% 16 months USA Sorenson et al. 1993 deisopropylatrazine atrazine 8.6 ± 1.9% 6 months USA Sorenson et al. 1993 azoxystrobin acid azoxystrobin < 1% - USA Reported in Roberts and Hutson, 1999 bitertanol benzoic acid bitertanol 21% 31 days - Reported in PSD 1994b p-hydroxy bitertanol bitertanol 1% 31 days - Reported in PSD 1994b 2-chlorobenzene sulfonamide chlorsulfuron 30 - 35% 3 months USA Reported in PSD 1991c (glasshouse)

©2008 AwwaRF. ALLRIGHTS RESERVED CGA 205374 and CGA 205375 combined difenoconazole 18 - 50% - USA Reported in PSD 1994j CGA 189138 difenoconazole 2% - USA Reported in PSD 1994j omethoate dimethoate 5% - USA Reported in PSD 1993j fomesafen amine, fomesafen amino acid and fomesafen <8% - USA Reported in PSD 1995a fomesafen nitro acid combined terbufos sulfone terbufos 18% 12 weeks - Reported in Roberts and Hutson, 1999 3-methyl phosphinico-proprionic acid glufosinate 42% 104 days - Reported in PSD 1990f

61 ammonium α,α,α-trifluoro-p-toluic acid hydramethylnon <5.1% - - Reported in PSD 1994i p-trifluoromethyl cinnamic acid hydramethylnon <5.1% - - Reported in PSD 1994i 1,5-bis(α,α,α-p-tolyl)-1,4-pentadien-3-one hydramethylnon <5.1% - - Reported in PSD 1994i saccharin metsulfuron-methyl 17% (glasshouse) 14 weeks USA Reported in PSD 1991d 3% - - Reported in PSD 1994c dihydroxy anilazine anilazine 36% 60 days - Reported in PSD 1994c 35.7% 60 days - Reported in PSD 1994c deethylatrazine atrazine 2.1% 32 days - Reported in Solomon et al. 1996 hydroxyatrazine atrazine 0.4% 94 days - Reported in Solomon et al. 1996 deisopropylatrazine atrazine 0.7% 32 days - Reported in Solomon et al. 1996 diaminochlorotriatrazine atrazine 0.3% 32 days - Reported in Solomon et al. 1996 Ia cyhalothrin 17% - - Reported in PSD 1988b ethyl-m-hydroxyphenyl carbamate desmedipham 28% - - Reported in PSD 1993f 1,3-diphenyl urea desmedipham <0.2% - - Reported in PSD 1993f N-phenyl carbamic acid-ethyl ester desmedipham <0.2% - - Reported in PSD 1993f diclofop acid diclofop-methyl 64 - 81% 64 days - Reported in PSD 1991e 4-(2,4-dichlorophenoxy)phenol diclofop-methyl trace - Germany Reported in PSD 1991e O-desmethyldimethoate dimethoate 10% 60 days Denmark Reported in PSD 1993j O,O-dimethylphosphorothioic acid dimethoate 5% 60 days Denmark Reported in PSD 1993j 3-desmethyl dimethomorph and 4-desmethyl dimethomorph 15% 7 days - Reported in PSD 1994g dimethomorph combined

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

aerobic soil (laboratory) 3-desmethyl dimethomorph and 4-desmethyl dimethomorph ~10 - 20% 7 days - Reported in PSD 1994g dimethomorph combined CONH2-fen esfenvalerate 1% 30 days - Reported in PSD 1992b 4’-OH-fen esfenvalerate 4% 30 days - Reported in PSD 1992b Cl-Vacid esfenvalerate 4% 30 days - Reported in PSD 1992b SD 50365 esfenvalerate 0.4% 30 days - Reported in PSD 1992b 3-phenoxybenzoic acid fenpropathrin 71% - UK Reported in PSD 1989b 2,2,3,3-tetramethyl cyclopropane carboxylic acid fenpropathrin 39% 8 weeks - Reported in PSD 1989b compound VII fluazinam 31.2% 90 days UK Reported in PSD 1994h compound VIII fluazinam 12% 30 days UK Reported in PSD 1994h compound XII fluazinam 7.2% 30 days UK Reported in PSD 1994h

©2008 AwwaRF. ALLRIGHTS RESERVED RH-4515 fluoroglycofen-ethyl 10.1% 68 days - Reported in PSD 1992a RH-5781 fluoroglycofen-ethyl 47.7% 2 days - Reported in PSD 1992a RH-5349 fluoroglycofen-ethyl 5% 2 days - Reported in PSD 1992a RH-9985 fluoroglycofen-ethyl 2.7% 2 days - Reported in PSD 1992a RH-4514 fluoroglycofen-ethyl 7.9% 68 days - Reported in PSD 1992a 3-methyl phosphinico-proprionic acid glufosinate 54% 26 days - Reported in PSD 1990f ammonium 41% 60 days USA Reported in PSD 1990f

62 HOE 64619 glufosinate 22% 26 days - Reported in PSD 1990f ammonium M1 imazaquin 0.2% 2 months - Reported in PSD 1993a

column leachate (laboratory) HOE 101630 amidosulfuron 20% 30 days - Reported in PSD 1994a dihydroxy anilazine anilazine 7% 30 days - Reported in PSD 1994c 6 - 10% 20 days - Reported in PSD 1994c monohydroxy anilazine anilazine 1% 20 days - Reported in PSD 1994c 1-isopropyl-3-phenyl urea buprofezin trace - - Reported in PSD 1993i N-(4-hydroxyphenyl)-N-isopropylurea buprofezin trace - - Reported in PSD 1993i melamine cyromazine 29% 26 days - Reported in PSD 1993l pyrimidinol diazinon 7.8 - 9.8% - - Reported in PSD 1991b compound II diazinon 13.4 - 15.2% - - Reported in PSD 1991b benzoxazolone fenoxaprop-ethyl 0.2 - 0.6% - - Reported in PSD 1990b fenoxaprop-ethyl acid fenoxaprop-ethyl 0.2% - - Reported in PSD 1990b α-carbomoyl-3-phenoxybenzyl-2,2,3,3- fenoxaprop-ethyl 9.1% 45 days - Reported in PSD 1989b tetramethyl cyclopropane carboxylate and 2,2,3,3-tetramethyl cyclopropane carboxylic acid combined M3 fenpyroximate 0.3 - 0.6% (soil) - - Reported in PSD 1995b 1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile fenpyroximate 0.2 - 1.7% (soil) - - Reported in PSD 1995b 1,3-dimethyl-5-phenoxypyrazole-4-carboxylic fenpyroximate 0.1% (soil) - - Reported in PSD 1995b acid fluzifop acid fluzifop-P-butyl 36 - 47% - - Reported in PSD 1988a

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

RH-5781 fluoroglycofen-ethyl 88 - 89% (soil e) 30 days - Reported in PSD 1992a 50 - 60% (soil f) - - Reported in PSD 1992a column leachate (laboratory) continued RH-5349 fluoroglycofen-ethyl 3 - 5% (soil e) 30 days - Reported in PSD 1992a RH-4514 fluoroglycofen-ethyl 1% (soil e) 30 days - Reported in PSD 1992a 4 - 7% (soil f) - - Reported in PSD 1992a f RH-0265-NH2, RH-5782, RH-670 and fluoroglycofen-ethyl 10% (soil ) - - Reported in PSD 1992a fluoroglycofen-ethyl combined fomesafen amine fomesafen 34.7 - 47.6% 82 days UK Reported in PSD 1995a (anaerobic soil e) 9.1 - 16.9% (soil f) 45 days UK Reported in PSD 1995a

©2008 AwwaRF. ALLRIGHTS RESERVED fomesafen amino acid fomesafen 16 - 33.9% 82 days UK Reported in PSD 1995a (anaerobic soil e) 5.3 - 5.4% (soil f) 45 days UK Reported in PSD 1995a fomesafen nitro acid fomesafen 0.7 - 0.8% 82 days UK Reported in PSD 1995a (anaerobic soil e) <0.5 - 1.3% (soil f) 45 days UK Reported in PSD 1995a saccharin metsulfuron-methyl 50 - 85% - - Reported in PSD 1991d methyl-2-(aminosulfonyl)benzoate metsulfuron-methyl 5 - 25% - - Reported in PSD 1991d

63 lysimeter studies 1-(6-chloro-pyridine-3-ylmethyl)-2-imino- imidacloprid 4.2% - Germany Reported in PSD 1993e imidazolidine 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro-2-imino- imidacloprid <0.6% - Germany Reported in PSD 1993e imidazollidine-5-ol 1-(6-chloro-pyridine-3-ylmethyl)-N-nitroso-2- imidacloprid <0.6% - Germany Reported in PSD 1993e imino-imidazolidine 6-chloro-nicotinic acid imidacloprid <0.6% - Germany Reported in PSD 1993e 1,3-bis[(6-chloro(3-pyridyl))methyl]imidazolidin- imidacloprid 0.2% - Germany Reported in PSD 1993e 2-imine

sewage sludge malonic acid kathon 886 >20% - - Reported in PSD 1993m N-methyl malonamic acid kathon 886 >20% - - Reported in PSD 1993m malonamic acid kathon 886 >20% - - Reported in PSD 1993m acetic acid kathon 886 <20% - - Reported in PSD 1993m

sewage sludge continued formic acid kathon 886 <20% - - Reported in PSD 1993m RH 886 oxide kathon 886 <20% - - Reported in PSD 1993m

estuarine sediment 2,4-dichlorophenol 2,4-D 0.5% 33 days - Reported in PSD 1993c

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

sediment /water e 2’,6’-diethyl-N-methoxymethyl-2-methyl alachlor 2.7% 30 days - Reported in PSD 1990d thioacetanilide 2’,6’-diethyl-N-methoxymethyl acetanilide alachlor 27.7% (anaerobic) 1 week - Reported in PSD 1990d 2-amino-4,6-dihydroxypyrimidine amdosulfuron 45% 84 days - Reported in PSD 1994a HOE 101630 amidosulfuron 30% 61 days - Reported in PSD 1994a dihydroxy anilazine anilazine 8.5% (water) 57 days - Reported in PSD 1994c 0.9% (sediment) 57 days - Reported in PSD 1994c monohydroxy anilazine anilazine 34.3% (water) 7 days - Reported in PSD 1994c 1.4% (sediment) 1 day - Reported in PSD 1994c monoamino anilazine anilazine 0.6% (water) 4 days - Reported in PSD 1994c 0.9% (sediment) 4 days - Reported in PSD 1994c bitertanol ketone bitertanol < 1% 120 days - Reported in PSD 1994b

©2008 AwwaRF. ALLRIGHTS RESERVED bitertanol benzoic acid bitertanol < 1% 120 days - Reported in PSD 1994b buprofezin sulphoxide buprofezin 13% 56 days - Reported in PSD 1993i TSO and T2SO combined cycloxydim 19 - 82% (pH 9.4) 28 days - Reported in PSD 1990e Ia cyhalothrin 26.9 - 32% 32 days - Reported in PSD 1988b Ib cyhalothrin 9 - 15.3% 32 days - Reported in PSD 1988b ethyl-m-hydroxyphenyl carbamate desmedipham 84% (water) 7 days - Reported in PSD 1993f 1.7% (sediment) 21 days - Reported in PSD 1993f diclofop acid diclofop-methyl 70% 7 days - Reported in PSD 1991e

64 40.2% (water) 14 days - Reported in PSD 1991e 77.9 % (sediment) 168 days - Reported in PSD 1991e 4-(2,4-dichlorophenoxy)phenol diclofop-methyl 10% 7 days - Reported in PSD 1991e 52.4 % (sediment) 168 days - Reported in PSD 1991e 210 352 epoxiconazole 0.4 - 1.1% 90 days - Reported in PSD 1994l 231 761 epoxiconazole 0.4 - 0.9% 90 days - Reported in PSD 1994l fenoxaprop-ethyl acid fenoxaprop-ethyl 47% (water) 1 day - Reported in PSD 1990b sediment /water e continued 6-chloro-3-dihydrobezoxazol-2-one fenoxaprop-ethyl 9.3% (water) 21 days - Reported in PSD 1990b fenoxaprop-ethyl acid fenoxaprop-ethyl 60.4% (sediment) 29 days - Reported in PSD 1990b 6-chloro-3-dihydrobezoxazol-2-one fenoxaprop-ethyl 3.8% (sediment) 21 days - Reported in PSD 1990b R0 15-6045 fenpropidin 15 - 16 % 28 - 84 days Switzerland Reported in PSD 1993b M3 fenpyroximate 5.8 - 18.3% d (water) 24 hours - Reported in PSD 1995d 4.6 - 16.1% 90 days - Reported in PSD 1995d 1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile fenpyroximate <5% d (water) 24 hours - Reported in PSD 1995d compound XII fluazinam 8% 0 weeks Netherlands Reported in PSD 1994h bis (4-fluorophenyl)methyl silanol flusilazole 48 - 60% 52 weeks - Reported in PSD 1989a 1H-1,2,4-triazole flusilazole 12% 52 weeks - Reported in PSD 1989a 1-(6-chloro-pyridine-3-ylmethyl)-2-imino- imidacloprid 8.8 - 12.3% - Reported in PSD 1993e imidazolidine 64% (anaerobic) 358 days - Reported in PSD 1993e 6-chloro-nicotinic acid imidacloprid 0.3 - 4.2% - Reported in PSD 1993e N-1-(6-chloro-pyridine-3-ylmethyl)-ethane-1,2- imidacloprid 0.3 - 4.2% - Reported in PSD 1993e diamine

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

propargyl butyl carbamate IPBC >97% (water, 1 day - Reported in PSD 1994n anaerobic) >80% (sterile) 29 days - Reported in PSD 1994n 2-propenyl butyl-carbamate IPBC 8% (sediment, 59 days - Reported in PSD 1994n anaerobic) 2-propenyl butyl-carbamate IPBC 34.7% (water, 59 days - Reported in PSD 1994n anaerobic) saccharin metsulfuron-methyl 8% 14 days - Reported in PSD 1991d 26 - 33% (sterile) 24 weeks - Reported in PSD 1991d 2-(aminosulfonyl) benzoic acid metsulfuron-methyl 14% 14 days - Reported in PSD 1991d 40% (sterile, 5 weeks - Reported in PSD 1991d anaerobic) 6 - 13% (non-sterile) - - Reported in PSD 1991d

©2008 AwwaRF. ALLRIGHTS RESERVED aqueous degradation (non-sterile) dihydroxy anilazine anilazine 3% 10 days - Reported in PSD 1994c monohydroxy anilazine anilazine 29% 10 days - Reported in PSD 1994c deethylatrazine atrazine 6.4% (anaerobic) 275 days - Reported in Solomon et al. 1996 deisopropylatrazine atrazine 2.6% (anaerobic) 275 days - Reported in Solomon et al.

65 1996 hydroxyatrazine atrazine 2.7 - 3% 70 days - Reported in PSD 1992c 6.6% (anaerobic) 183 days - Reported in Solomon et al. 1996 2-chlorobenzene sulfonamide chlorsulfuron 9 - 11% (anaerobic) 10 weeks - Reported in PSD 1991c 2-amino-4-methoxy-6-methyl-1,3,5-triazine chlorsulfuron 21 - 25% (anaerobic) 52 weeks - Reported in PSD 1991c 4-fluoro-3-phenoxybenzaldehyde cyfluthrin 3% 144 hours - Reported in PSD 1988c 4-fluoro-3-phenoxybenzoic acid cyfluthrin 8.5% 144 hours - Reported in PSD 1988c fenoxaprop-ethyl acid fenoxaprop-ethyl 44% 192 hours - Reported in PSD 1990b 6-chloro-2,3-dihydroxybenzoxazol-2-one fenoxaprop-ethyl 2.4% 192 hours - Reported in PSD 1990b N-methyl malonamic acid kathon 886 >20% - - Reported in PSD 1993m malonic acid kathon 886 <20% - - Reported in PSD 1993m malonamic acid kathon 886 <20% - - Reported in PSD 1993m

aqueous photolysis 1,2,4-benzenetriol 2,4-D > 10% - - Reported in PSD 1993c dihydroxy anilazine anilazine 86.9% 364 hours - Reported in PSD 1994c deethylatrazine atrazine 2.8% 15 days - Reported in Solomon et al. 1996 38% 7 days - Reported in PSD 1992c hydroxyatrazine atrazine 2.6% 15 days - Reported in Solomon et al. 1996 deisopropylatrazine atrazine 1.2% 6.9 days - Reported in Solomon et al. 1996 4.3% 7 days - Reported in PSD 1992c deisopropyl deethylatrazine atrazine 22% 7 days - Reported in PSD 1992c

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

diaminochlorotriatrazine atrazine 0.9% 15 days - Reported in Solomon et al. 1996 aqueous photolysis continued DIHA atrazine 1.2% 6.9 days - Reported in Solomon et al. 1996

DEHA atrazine 0.4% 15 days - Reported in Solomon et al. 1996 hydroxyatrazine atrazine 14.6% 7 days - Reported in PSD 1992c 1,2,4-triazole bitertanol 52.5% - - Reported in PSD 1994b bitertanol 12.0% - - Reported in PSD 1994b 2-amino-4-methoxy-6-methyl-1,3,5-triazine chlorsulfuron 5 - 44% - - Reported in PSD 1991c

©2008 AwwaRF. ALLRIGHTS RESERVED 2-chlorobenzene sulfonamide chlorsulfuron 4 - 21% - - Reported in PSD 1991c 2-chlorophenylsulfonyl urea chlorsulfuron 0 - 4% - - Reported in PSD 1991c T1S cycloxydim 10 - 45% (pH 5.5) - - Reported in PSD 1990e 6 - 43% (pH 9.4) - - Reported in PSD 1990e T2S cycloxydim 3 - 9% (pH 5.5) - - Reported in PSD 1990e 2 - 7% (pH 9.4) - - Reported in PSD 1990e TSO cycloxydim 6 - 11% (pH 5.5) - - Reported in PSD 1990e TSO2 and T2SO2 combined cycloxydim < 3% (pH 5.5) - - Reported in PSD 1990e

66 TSO and T2SO combined cycloxydim 2 - 8% (pH 9.4) - - Reported in PSD 1990e ethyl-m-hydroxyphenyl carbamate desmedipham 5% (pH 3.8) - - Reported in PSD 1993f 4-(2,4-dichlorophenoxy)phenol diclofop-methyl 0 - 33% 237 - 288 - Reported in PSD 1995e hours DPX M6316 triazine amine DPX M6316 11% - - Reported in PSD 1988d DPX M6316 triazine urea DPX M6316 14% - - Reported in PSD 1988d DPX M6316 TP1 DPX M6316 7% - - Reported in PSD 1988d Cl-Vacid esfenvalerate 17.3% 10 days - Reported in PSD 1992b fenoxaprop-ethyl acid fenoxaprop-ethyl 6.9% 192 hours - Reported in PSD 1990b 4-(6-chloro-2-benzoxazolyloxy)phenol fenoxaprop-ethyl 6.4% 192 hours - Reported in PSD 1990b 3-phenoxybenzoic acid fenpropathrin 11 – 39% 6 weeks - Reported in PSD 1989b 2,2,3,3-tetramethyl cyclopropane carboxylic acid fenpropathrin 2 – 39% 6 weeks - Reported in PSD 1989b α-(2,2,3,3-tetramethylcyclopropyl)-3- fenpropathrin 5 – 13% 6 weeks - Reported in PSD 1989b phenoxybenzyl cyanide α-carbomoyl-3-phenoxybenzyl-2,2,3,3- fenpropathrin 4 - 28% 6 weeks - Reported in PSD 1989b tetramethyl cyclopropane carboxylate M3 and M4 combined fenpyroximate 10% 24 hours - Reported in PSD 1995d aqueous photolysis continued 1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile fenpyroximate 47.5 - 58.3% 6 hours - Reported in PSD 1995d compound V fluazinam 51% (pH 9) 30 days - Reported in PSD 1994h minor (pH 5) 30 days - Reported in PSD 1994h RH-4514 fluoroglycofen-ethyl 5.8% - - Reported in PSD 1992a 1H-1,2,4-triazole flusilazole <5% 30 days - Reported in PSD 1989a 3-methyl phosphinico-proprionic acid glufosinate 19% (pH 9) 120 hours - Reported in PSD 1990f ammonium

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

1,5-bis(α,α,α-p-tolyl)-1,4-pentadien-3-one hydramethylnon <8% 90 minutes - Reported in PSD 1994i TDTP hydramethylnon <8% 90 minutes - Reported in PSD 1994i α,α,α-trifluoro-p-toluic acid hydramethylnon <8% 90 minutes - Reported in PSD 1994i p-trifluoromethyl cinnamic acid hydramethylnon <8% 90 minutes - Reported in PSD 1994i quinoline-3-carboxylic acid imazaquin 14% 24 hours - Reported in PSD 1993a 2H-azolidino[3,4-b]quinoline-1,3-dione imazaquin 21% 48 hours - Reported in PSD 1993a 3-imino-2H-azolidino[3,4-b]quinolin-1-one imazaquin 13% 48 hours - Reported in PSD 1993a quinoline-2,3-dicarboxylic acid imazaquin ~30% 48 hours - Reported in PSD 1993a malonic acid kathon 886 >20% - - Reported in PSD 1993m N-methyl malonamic acid kathon 886 >20% - - Reported in PSD 1993m malonamic acid kathon 886 >20% - - Reported in PSD 1993m acetic acid kathon 886 <20% - - Reported in PSD 1993m formic acid kathon 886 <20% - - Reported in PSD 1993m

©2008 AwwaRF. ALLRIGHTS RESERVED methyl-2-(aminosulfonyl)benzoate metsulfuron-methyl 58% (dark) 14 days - Reported in PSD 1991d 13% 4 days - Reported in PSD 1991d saccharin metsulfuron-methyl 7% 14 days - Reported in PSD 1991d 2-(aminosulfonyl) benzoic acid metsulfuron-methyl 7% 14 days - Reported in PSD 1991d

hydrolysis (sterile) alachlor oxamic acid alachlor 2.2 - 25.1% 28 days - Reported in PSD 1990d

67 alachlor ethane sulfonic acid alachlor 0.3 - 5.5% 28 days - Reported in PSD 1990d 2-amino-4,6-dimethoxypyrimidine amidosulfuron 21% (pH 5) 30 days - Reported in PSD 1994a 2% (pH 6) 30 days - Reported in PSD 1994a product A (unidentified) amidosulfuron 23% 30 days Reported in PSD 1994a monohydroxy anilazine anilazine 65.3% (pH 8.9) 52 hours - Reported in PSD 1994c 52.1% (pH 7) 23 days - Reported in PSD 1994c

monohydroxy anilazine continued anilazine 24.1% (pH 5) 12 days - Reported in PSD 1994c dihydroxy anilazine anilazine 0.19% (pH 8.9) 48 hours - Reported in PSD 1994c 0.97% (pH 7) 23 days - Reported in PSD 1994c 52.1% (pH 8.9) 18 days - Reported in PSD 1994c carbofuran benfuracarb 54% (pH 7) - - Reported in PSD 1998a 9% (pH 9) - - Reported in PSD 1998a 13.6% (pH 7.1) 21.5 hours - Reported in PSD 1998a carbofuran phenol benfuracarb 35% (pH 7) - - Reported in PSD 1998a 76% (pH 9) - - Reported in PSD 1998a 10.7% (pH 7.1) 21.5 hours - Reported in PSD 1998a N-hydroxy-methyl carbofuran benfuracarb 24% (pH 7.1) 21.5 hours - Reported in PSD 1998a

1-tert-butyl-3-isopropyl-5-phenyl-2-biuret buprofezin 42% (pH 4) 11 days - Reported in PSD 1993i 1-isopropyl-3-phenyl urea buprofezin 15% (pH 4) 11 days - Reported in PSD 1993i TSO cycloxydim 12 - 16% (pH 7) 32 days - Reported in PSD 1990e 19% (pH 3) 0 days - Reported in PSD 1990e 7 - 11% (pH 5) 14 days - Reported in PSD 1990e 10 - 18% (pH 9) 7 days - Reported in PSD 1990e T1S cycloxydim 3 - 6% (pH 7) 32 days - Reported in PSD 1990e

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

7% (pH 3) 30 minutes - Reported in PSD 1990e 4 - 7% (pH 5) 14 days - Reported in PSD 1990e 4% (pH 9) 7 days - Reported in PSD 1990e T2S cycloxydim 3 - 9% (pH 7) 32 days - Reported in PSD 1990e 3% (pH 9) 7 days - Reported in PSD 1990e T2SO cycloxydim 10% (pH 3) 6 days - Reported in PSD 1990e T2 cycloxydim 70% (pH 3) 6 days - Reported in PSD 1990e 52% (pH 5) 14 days - Reported in PSD 1990e diphenylurea desmedipham <0.6% - - Reported in PSD 1993f N-demethyldimefuron dimefuron <10% - - Reported in PSD 1993h compound D dimefuron <10% - - Reported in PSD 1993h compound G dimefuron <10% - - Reported in PSD 1993h [(3-chlorophenyl)amino]-N,N- dimefuron <10% - - Reported in PSD 1993h

©2008 AwwaRF. ALLRIGHTS RESERVED dimethylcarboxamide hydrolysis (sterile) continued [(3-chloro-4-hydroxyphenyl)amino]-N,N- dimefuron <10% - - Reported in PSD 1993h dimethylcarboxamide O-desmethyldimethoate dimethoate 12% (pH 5) 30 days - Reported in PSD 1993j 22% (pH 7) 30 days - Reported in PSD 1993j

68 62% (pH 9) 30 days - Reported in PSD 1993j O,O-dimethylphosphorothioic acid dimethoate ND (pH 5) 30 days - Reported in PSD 1993j 2% (pH 7) 30 days - Reported in PSD 1993j 36% (pH 9) 30 days - Reported in PSD 1993j Cl-Vacid esfenvalerate 14.9% (pH 9) 28 days - Reported in PSD 1992b M3 fenpyroximate 6.7% 30 days - Reported in PSD 1995b 1,3-dimethyl-5-phenoxypyrazole-4-carbonitrile fenpyroximate 10.1% 30 days - Reported in PSD 1995b RH-9985 fluoroglycofen-ethyl 48.1% (pH 5) 30 days - Reported in PSD 1992a 64.7% (pH 7) 30 days - Reported in PSD 1992a 21.3% (pH 9) 30 days - Reported in PSD 1992a RH-5781 fluoroglycofen-ethyl 4% (pH 5) 30 days - Reported in PSD 1992a 13.8% (pH 7) 30 days - Reported in PSD 1992a 77.7% (pH 9) 30 days - Reported in PSD 1992a M1 imazaquin 10% (pH 9) 30 days - Reported in PSD 1993a propargyl butyl carbamate IPBC 12% (pH 7) 30 days - Reported in PSD 1994n 1% (pH 5) 30 days - Reported in PSD 1994n malonic acid kathon 886 <20% - - Reported in PSD 1993m N-methyl malonamic acid kathon 886 >20% - - Reported in PSD 1993m malonamic acid kathon 886 <20% - - Reported in PSD 1993m methyl-2-(aminosulfonyl)benzoate metsulfuron-methyl 26% 30 days - Reported in PSD 1991d saccharin metsulfuron-methyl 37% 30 days - Reported in PSD 1991d

soil photolysis dihydroxy anilazine anilazine 75% 20 days - Reported in PSD 1994c deethylatrazine atrazine 19.2% 3.5 days - Reported in Solomon et al. 1996

Degradate formation Degradate Parent pesticide a Percentage of Time c Country Reference parent pesticide b

deisopropylatrazine atrazine 7.9% 7 days - Reported in Solomon et al. 1996 soil photolysis continued diaminochlorotriatrazine atrazine 6.8% 22 days - Reported in Solomon et al. 1996 pyrimidinol diazinon 56 - 62% 24 hours - Reported in PSD 1991b 56% 24 hours - Reported in PSD 1991b CONH2-fen esfenvalerate 48.4% - - Reported in PSD 1992b 25% 10 days - Reported in PSD 1992b COOH-fen esfenvalerate 2% - - Reported in PSD 1992b Cl-Vacid esfenvalerate 4.5% - - Reported in PSD 1992b dec-fen esfenvalerate 0.9% - - Reported in PSD 1992b

©2008 AwwaRF. ALLRIGHTS RESERVED α-carbomoyl-3-phenoxybenzyl-2,2,3,3- fenpropathrin 6 – 44% 5 – 7 days - Reported in PSD 1989b tetramethyl cyclopropane carboxylate 3 – 26% (dark) 14 days - Reported in PSD 1989b CGA 257 777 fludioxonil 8% 7 days - Reported in PSD 1995b RH-5781 fluoroglycofen-ethyl 5.3% 13 days - Reported in PSD 1992a RH-9985 fluoroglycofen-ethyl 19% 13 days - Reported in PSD 1992a 3-methyl phosphinico-proprionic acid glufosinate 9.7% 16 days - Reported in PSD 1990f ammonium

69 HOE 83348 HOE 070542 8.9% 45 days - Reported in PSD 1990c HOE 88988 HOE 070542 3.6% 16 days - Reported in PSD 1990c HOE 88989 HOE 070542 1.6% 7 days - Reported in PSD 1990c HOE 72829 HOE 070542 13% 3.7 days - Reported in PSD 1990c HOE 87606 HOE 070542 4.6% 16 days - Reported in PSD 1990c 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro-2-imino- imidacloprid 6.3 - 6.5% 7 - 15 days - Reported in PSD 1993e imidazollidine-5-ol 1-(6-chloro-pyridine-3-ylmethyl)-N-nitroso-2- imidacloprid <3% 7 - 15 days - Reported in PSD 1993e imino-imidazolidine 6-chloro-nicotinic acid imidacloprid <3% 7 - 15 days - Reported in PSD 1993e 1-(6-chloro-pyridine-3-ylmethyl)-N-nitro-2-imino- imidacloprid <3% 7 - 15 days - Reported in PSD 1993e 2,3-dihydro-imidazole and 1-(6-chloro-pyridine- 3-ylmethyl)-imazolidine-2-one saccharin metsulfuron-methyl 10% 30 days - Reported in PSD 1991d 2-aminosulfonyl) benzoic acid metsulfuron-methyl 8% 30 days - Reported in PSD 1991d methyl-2-(aminosulfonyl)benzoate metsulfuron-methyl <1% - - Reported in PSD 1991d thin-layer photolysis (non soil) 4-fluoro-3-phenoxybenzaldehyde cyfluthrin 2% 9 days - Reported in PSD 1988c 4-fluoro-3-phenoxybenzoic acid cyfluthrin 4% 9 days - Reported in PSD 1988c a - pesticide identified in the reference as the source of the degradate b - peak percentage formation of degradate during study c - time to peak degradate formation d - soil and water system e - soil before leaching in column leachate study f - soil after leaching in column leachate study

APPENDIX 2. THE DEGRADATION RATE OF PESTICIDE DEGRADATES IN THE ENVIRONMENT

a Test matrix/system Degradate Parent pesticide Half-life / DT50 Reference

aqueous photolysis albendazole sulfoxide albendazole 0.034 - 1.05 days Weerasinghe et al. 1992 albendazole sulfone albendazole 0.014 - 1.77 days Weerasinghe et al. 1992 2-aminoalbendazole sulfone albendazole 0.163 - 1.94 days Weerasinghe et al. 1992

surface water methamidophos acephate 8.6 - 17.8 days Sundaram, 1993 ethyl-m-hydroxyphenyl carbamate desmedipham 26 days Reported in PSD 1993f disulfoton sulfoxide disulfoton 10.4 days (estuarine) Lacorte et al. 1995 disulfoton sulfone disulfoton 8.19 days (estuarine) Lacorte et al. 1995 fenthion sulfoxide fenthion 6.9 days (estuarine) Lacorte et al. 1995

©2008 AwwaRF. ALLRIGHTS RESERVED kresoxim-methyl acid kresoxim-methyl 337 - 383 days Reported in Roberts and Hutson, 1999 2,6-di-tert-butyl-4-methylphenyl terbutol 47.1 months Suzuki et al. 1998 carbamate 2,6-di-tert-butyl-4-carboxyphenyl N- terbutol 63.6 months Suzuki et al. 1998 methylcarbamate 2,6-di-tert-butyl-4-carboxyphenyl terbutol 29.4 months Suzuki et al. 1998 carbamate

71 2,6-di-tert-butyl-4-methylphenol terbutol 42 months Suzuki et al. 1998 2,6-di-tert-butyl-4-carboxyphenol terbutol 25 months Suzuki et al. 1998

hydrolysis (sterile) RH-9985 fluoroglycofen-ethyl 15.1 days (pH 9) Reported in PSD 1992a 5.3 days (pH 9) Reported in PSD 1992a

aerobic soil z-3-chloroallyl alcohol 1,3-dichloropropene (z-isomer) 2.3 - 4.2 days Leistra et al. 1991 e-3-chloroallyl alcohol 1,3-dichloropropene (e-isomer) 0.8 - 1.4 days Leistra et al. 1991 methamidophos acephate 3.5 - 9.3 days Sundaram, 1993 dihydroxy anilazine anilazine 21 - 45 days Reported in PSD 1994c 2-chloro-2',6'-diethylacetanilide alachlor 2.4 days Fava et al. 2000 2-hydroxy-2',6'-diethylacetanilide alachlor 0.8 days Fava et al. 2000 2,6-diethylaniline alachlor 1.3 days Fava et al. 2000 carbouran benfuracarb 36 - 44 days Reported in PSD 1998a 30 - 34 days Reported in PSD 1998a 11 - 23 days Reported in PSD 1998a 1-naphthol carbaryl 14.93 days Menon and Gopal, 2003 3,5,6-trichloro-2-pyridinol chlorpyrifos 42 - 49 days Baskaran et al. 2003 cis-3-chloroallylalcohol cis-1,3-dichloropropene 1.2 - 1.8 days Dijk, 1974 clodinafop-propargyl free acid clodinafop-propargyl 5 - 20 days Reported in Tomlin, 2000 melamine cyromazine 175 - 186 days (estimated) Reported in PSD 1993l 150 - 730 days (estimated) Reported in PSD 1993l dacthal mono-acid dacthal 2.8 ± 0.1 days Wettasinghe and Tinsley, 1993

a Test matrix/system Degradate Parent pesticide Half-life / DT50 Reference

aqueous photolysis dacthal di-acid dacthal > 300 days Wettasinghe and Tinsley, 1993 ethyl-m-hydroxyphenyl carbamate desmedipham 21 days (15oC) Reported in PSD 1993f 9 days (25oC) Reported in PSD 1993f 27 days (15oC) Reported in PSD 1993f 21 days (25oC) Reported in PSD 1993f diazoxon diazinon 88 days Reported in Tomlin, 2000 17 hours Reported in PSD 1991b 3,6-dichlorosalicylic acid dicamba > 40 days Pearson et al. 1996 dicolfop-methyl and diclofop acid diclofop-methyl 21 - 93 days Reported in PSD 1991e combined 10 - 38 days Reported in PSD 1991e 21 - 52 days Reported in PSD 1991e diclofop acid diclofop-methyl 10 - 30 days Reported in PSD 1991e

©2008 AwwaRF. ALLRIGHTS RESERVED 6 - 38 days Reported in PSD 1991e 63 days Reported in PSD 1991e 26 - 28.4 days Reported in PSD 1991e fenoxaprop-ethyl acid fenoxaprop-ethyl 5 - 14 days Reported in PSD 1990b fluroxypyr fluroxpyr-meptyl < 7 days Reported in Roberts, 1998 RH-5781 fluoroglycofen-ethyl 14 - 128 days Reported in PSD 1992a HOE 35950 glufosinate ammonium 4 - 42 days Reported in PSD 1990f 3-methyl phosphinico-proprionic glufosinate ammonium 165 days Reported in PSD 1990f

72 acid 7 - 14 days Reported in PSD 1990f 13 - 22 days Reported in PSD 1990f propargyl butyl carbamate IPBC 4.3 days Reported in PSD 1994n kresoxim-methyl acid kresoxim-methyl 38 -131 days Reported in Roberts and Hutson, 1999 methyl isothiocyanate metam sodium 4 - 5 days Reported in Roberts and Hutson, 1999

2-ethyl-6-methylaniline metolachlor 1.7 days Fava et al. 2000 paraoxon parathion 4 hours a Saffih-Hdadi et al. 2003 2,6-di-tert-butyl-4-methylphenyl terbutol 291 days Suzuki et al. 2001 carbamate 2,6-di-tert-butyl-4-carboxyphenyl N- terbutol 173 days Suzuki et al. 2001 methylcarbamate 2,6-di-tert-butyl-4-carboxyphenyl terbutol 184 days Suzuki et al. 2001 carbamate tridimenol triadimefon > 2 years Bromilow et al. 1999 trans-3-chloroallylalcohol trans-1,3-dichloropropene 0.4 - 0.6 days Dijk, 1974 3,5,6-trichloro-2-pyridinol triclopyr 30 - 90 days Reported in Tomlin, 2000

anaerobic soil diclofop acid diclofop-methyl > 150 days Reported in PSD 1991e fenoxaprop-ethyl acid fenoxaprop-ethyl 30 days Reported in PSD 1990b

sediment

a Test matrix/system Degradate Parent pesticide Half-life / DT50 Reference

aqueous photolysis ethyl-m-hydroxyphenyl carbamate desmedipham 43 days Reported in PSD 1993f

water/sediment system ethyl-m-hydroxyphenyl carbamate desmedipham 25 days Reported in PSD 1993f diclofop acid diclofop-methyl 27 days Reported in PSD 1991e 4-(2,4-dichlorophenoxy)phenol diclofop-methyl 32 days Reported in PSD 1991e fluroxypyr fluroxpyr-meptyl < 7 days Reported in Roberts, 1998 propargyl butyl carbamate IPBC 11.5 days (anaerobic) Reported in PSD 1994n kresoxim-methyl acid kresoxim-methyl 464 - 473 days Reported in Roberts and Hutson, 1999

sewage sludge degradation O,O-dimethyl phosphorodithioate dimethoate 1 day a Reported in PSD 1993j

a - DT100 73

APPENDIX 3. DEGRADATE ORGANIC CARBON PARTITION COEFFICIENT (KOC)

a -3 -1 -3 -1 Degradate Parent pesticide Details Kd (cm g ) Koc (cm g ) Reference

2,4-dichlorophenol 2,4-D sand 2.64 447.5 a Haberhauer et al. 2000 sandy silt loam 4.39 182.9 a Haberhauer et al. 2000 sandy loam 2.6 481.5 a Haberhauer et al. 2000 clay loam 5.02 185.9 a Haberhauer et al. 2000 2-chloro-2',6'- alachlor determined by HPLC - 148 Fava et al. 2000 diethylacetanilide 2-hydroxy-2',6'- alachlor determined by HPLC - 45 Fava et al. 2000 diethylacetanilide 2,6-diethylaniline alachlor determined by HPLC - 357 Fava et al. 2000 alachlor ethane sulfonic acid alachlor - - 182 Reported in Aga and Thurman, 2001 ©2008 AwwaRF. ALLRIGHTS RESERVED 4,6-dihydroxypyrimidin-2-yl- amidosulfuron determined by HPLC - 0.4 Reported in PSD 1994a urea 2-amino-4,6- amidosulfuron sand 2.47 211 Reported in PSD 1994a dimethyoxypyrimidine loamy sand 0.23 89 Reported in PSD 1994a sandy loam 8.25 625 Reported in PSD 1994a loamy sand 1.06 663 Reported in PSD 1994a sandy loam 1.81 696 Reported in PSD 1994a 75 sandy loam 4.11 395 Reported in PSD 1994a silty clay loam 81.28 11289 Reported in PSD 1994a clay 16.51 917 Reported in PSD 1994a determined by HPLC - 29 Reported in PSD 1994a HOE 101630 amidosulfuron sand 0.08 51 Reported in PSD 1994a clay 0.43 24 Reported in PSD 1994a loamy sand 0.71 24 Reported in PSD 1994a sandy loam 0.83 63 Reported in PSD 1994a sandy loam 0.51 57 Reported in PSD 1994a determined by HPLC - 3 Reported in PSD 1994a dihydroxy anilazine anilazine sand 2.97 512 Reported in PSD 1994c sandy loam 0.92 144 Reported in PSD 1994c silt loam 7.39 437 Reported in PSD 1994c clay loam 3.97 310 Reported in PSD 1994c deethylatrazine atrazine - - 110 Steinheimer and Scoggin, 2001 silt loam 0.3 300 a Mills and Thurman, 1994 sand 6.5 46 b Brouwer et al. 1990 sand 0.96 24 b Brouwer et al. 1990 deethylatrazine continued atrazine loamy sand 0.58 25 b Brouwer et al. 1990 loam 0.24 24 b Brouwer et al. 1990 clay 1.02 36.1 Reported in Solomon et al. 1996 sand 0.06 12.2 Reported in Solomon et al. 1996 sandy loam 0.36 31.8 Reported in Solomon et al. 1996 deisopropylatrazine atrazine - - 130 Steinheimer and Scoggin, 2001 silt loam 0.4 400 a Mills and Thurman, 1994 sand 8.6 62 b Brouwer et al. 1990

a -3 -1 -3 -1 Degradate Parent pesticide Details Kd (cm g ) Koc (cm g ) Reference

sand 1.2 31 b Brouwer et al. 1990 loamy sand 0.73 32 b Brouwer et al. 1990 loam 0.41 41 b Brouwer et al. 1990 clay 2.73 97 Reported in Solomon et al. 1996 sand 0.16 30 Reported in Solomon et al. 1996 sandy loam 0.51 45 Reported in Solomon et al. 1996 loam 0.27 58 Reported in Solomon et al. 1996 loam 0.21 44.9 Reported in Solomon et al. 1996 diaminochlorotriazine atrazine clay 1.56 55 Reported in Solomon et al. 1996

sand 0.16 31 Reported in Solomon et al. 1996 sandy loam 0.65 58 Reported in Solomon et al. 1996 loam 0.36 76 Reported in Solomon et al. 1996 hydroxyatrazine atrazine sand 82 590 b Brouwer et al. 1990 b ©2008 AwwaRF. ALLRIGHTS RESERVED sand 4.1 103 Brouwer et al. 1990 loamy sand 3.7 161 b Brouwer et al. 1990 loam 1.7 170 b Brouwer et al. 1990 clay 389 13797 Reported in Solomon et al. 1996 sand 1.98 374 Reported in Solomon et al. 1996 sandy loam 6.52 583 Reported in Solomon et al. 1996 loam 12.1 2573 Reported in Solomon et al. 1996 2-amino-N-isopropyl bentazone silty clay loam - 59 ± 5 Gaston et al. 1996

76 benzamide clay - 250 ± 10 Gaston et al. 1996 N-methyl bentazone bentazone silty clay loam - 97 ± 7 Gaston et al. 1996 clay - 350 ± 20 Gaston et al. 1996 3,5,6-trichloro-2-pyridinol chlorpyrifos red brown earth 1.62 - 2.86 70 - 159 Baskaran et al. 2003 3,5,6-trichloro-2-pyridinol chlorpyrifos black earth 0.45 - 2.53 76 - 126 Baskaran et al. 2003 desmethylpropanenitrile cyanazine silt loam 1.77 - 2.85 110 - 133 Reddy et al. 1997 cyanazine desmethylpropanenitrile cyanazine loamy sand 0.18 15 Reddy et al. 1997 cyanazine continued silty clay 1.69 89 Reddy et al. 1997 hydroxyacid cyanazine cyanazine silt loam 1.59 - 2.79 99 - 130 Reddy et al. 1997 loamy sand 0.13 11 Reddy et al. 1997 silty clay 1.17 62 Reddy et al. 1997 deethylcyanazine cyanazine silt loam 1.05 - 1.76 65 - 82 Reddy et al. 1997 loamy sand 0.31 26 Reddy et al. 1997 silty clay 1.44 76 Reddy et al. 1997 cyanazine amide cyanazine silt loam 0.64 - 1.08 40 - 50 Reddy et al. 1997 loamy sand 0.19 16 Reddy et al. 1997 silty clay 1.43 75 Reddy et al. 1997 chloroacid cyanazine cyanazine silt loam 0.17 - 0.23 10 - 11 Reddy et al. 1997 loamy sand 0.08 7 Reddy et al. 1997 silty clay 0.21 11 Reddy et al. 1997 3,6-dichlorosalicylic acid dicamba silt loam - 504 Pearson et al. 1996 diclofop acid diclofop-methyl sandy silt loam 0.7 191 Reported in PSD 1991e sand 1.8 334 Reported in PSD 1991e

a -3 -1 -3 -1 Degradate Parent pesticide Details Kd (cm g ) Koc (cm g ) Reference

silt loam 1.7 283 Reported in PSD 1991e 4-chlorophenol dichloroprop sand 1.15 194.9 a Haberhauer et al. 2000 sandy silt loam 2.29 95.4 a Haberhauer et al. 2000 sandy loam 1.23 227.8 a Haberhauer et al. 2000 clay loam 2.61 96.7 a Haberhauer et al. 2000 fluroxypyr fluroxpyr-meptyl sandy loam 1.7 - Reported in Tomlin, 2000

HOE 35956 glufosinate sand - 16 Reported in PSD 1990f ammonium imidacloprid-guanidine imidacloprid clay loam - 211 Cox et al. 1997 silt loam - 189 Cox et al. 1997 sandy loam - 209 Cox et al. 1997 imidacloprid-guanidine-olefin imidacloprid clay loam - 3805 Cox et al. 1997 silt loam - 3667 Cox et al. 1997

©2008 AwwaRF. ALLRIGHTS RESERVED sandy loam - 2129 Cox et al. 1997 imidacloprid-urea imidacloprid clay loam - 2829 Cox et al. 1997 silt loam - 3083 Cox et al. 1997 sandy loam - 2314 Cox et al. 1997 kresoxim-methyl acid kresoxim-methyl - - 17 - 24 Reported in Tomlin, 2000

2-methyl-4-chlorophenol MCPA sand 1.05 178 a Haberhauer et al. 2000 sandy silt loam 2.97 123.8 a Haberhauer et al. 2000 a 77 sandy loam 1.41 261.1 Haberhauer et al. 2000 clay loam 3.72 137.8 a Haberhauer et al. 2000 metolachlor ethane sulfonic metolachlor - - 195 Reported in Aga and Thurman, 2001 acid 2-ethyl-6-methylaniline metalochlor determined by HPLC - 197 Fava et al. 2000

a - Koc or Kd calculated using % organic carbon data presented in the reference b - Kom, organic matter partition coefficient

(Koc is the sorption of a compound to soil normalized for the organic carbon content of that soil, whilst Kom is the sorption of a compound to soil normalized for the organic matter content of that soil)

APPENDIX 4. THE OCCURRENCE OF PESTICIDE DEGRADATES IN THE ENVIRONMENT

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

Soil topsoil (0-30 cm) 3-chlorallyl alcohol 1,3-dichloropropene ND 10 µg kg-1 USA Obreza and Ontermaa, 1991 2-chloro-2',6'-diethylacetanilide alachlor ND 10 µg g-1 Germany Heyer and Stan, 1995 2,6-diethylaniline alachlor ND 10 µg g-1 Germany Heyer and Stan, 1995 alachlor ethane sulfonic acid alachlor 43.5 - 210 µg kg-1 - USA Aga and Thurman, 2001 deethylatrazine atrazine < 12 - 60 µg kg-1 - USA Mills and Thurman, 1994

14 ± 2 ppb 1 - 5 ppb Canada Khan and Saidak, 1981 ©2008 AwwaRF. ALLRIGHTS RESERVED < 1 - 15.3 µg kg-1 - Canada Raju et al. 1993 0.04 - 0.11 ± 0.01 µg g-1 - USA Winkelmann and Klaine, 1991 deisopropylatrazine atrazine < 4 - 27 µg kg-1 - USA Mills and Thurman, 1994

< 1 - 10.08 µg kg-1 - Canada Raju et al. 1993 0.01 - 0.02 - USA Winkelmann and Klaine, 1991 hydroxyatrazine atrazine 296 ± 27 - 378 ± 30 ppb 1 - 5 ppb Canada Khan and Saidak, 1981

79 < 1 - 52.1 µg kg-1 - Canada Raju et al. 1993 0.41 ± 0.08 - 0.5 µg g-1 - USA Winkelmann and Klaine, 1991 deethylhydroxyatrazine atrazine 47 ± 4 - 17 ± 2 ppb 1 - 5 ppb Canada Khan and Saidak, 1981 deisopropylhydroxyatrazine atrazine 23 ± 2 - 64 ± 8 ppb 1 - 5 ppb Canada Khan and Saidak, 1981 carbofuran benfuracarb < 1 - 6.3 mg kg-1 - Japan Reported in PSD 1998a SDS1449 chlorthal-dimethyl ND - 0.11 kg ha-1 0.01 ppm USA Niemczyk and Krause, 1994 SDS954 chlorthal-dimethyl ND - 2.09 kg ha-1 0.01 ppm USA Niemczyk and Krause, 1994 1-(2,4-dichlorophenyl) ethan-1-ol chlorfenvinphos ND 2 mg kg-1 - Reported in PSD 1994k 0.3 mg kg-1 c - Belgium Reported in PSD 1994k 0.3 mg kg-1 c - Belgium Reported in PSD 1994k 2-hydroxy-4-chlorobenzoic acid chlorfenvinphos 5.6±0.2 mg kg-1 0.02 mg kg-1 Belgium Reported in PSD 1994k 3.2 mg kg-1 c - Belgium Reported in PSD 1994k 4.7 mg kg-1 c - Belgium Reported in PSD 1994k 5.7 mg kg-1 c - Belgium Reported in PSD 1994k 5.0 mg kg-1 c - Belgium Reported in PSD 1994k 2,4-dichloroacetophenone chlorfenvinphos 0.4 mg kg-1 c - Belgium Reported in PSD 1994k 0.4 mg kg-1 c - Belgium Reported in PSD 1994k 0.3 mg kg-1 c - Belgium Reported in PSD 1994k 2,4-dichlorophenacyl chloride chlorfenvinphos 0.1 mg kg-1 - - Reported in PSD 1994k 3.5±0.2 mg kg-1 0.02 mg kg-1 Belgium Reported in PSD 1994k 4.8 mg kg-1 c - Belgium Reported in PSD 1994k 4.3 mg kg-1 c - Belgium Reported in PSD 1994k 3.5 mg kg-1 c - Belgium Reported in PSD 1994k 3.3 mg kg-1 c - Belgium Reported in PSD 1994k 2,4-dichlorobenzoic acid chlorfenvinphos 7.3±0.3 mg kg-1 0.02 mg kg-1 Belgium Reported in PSD 1994k

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

4.7 mg kg-1 c - Belgium Reported in PSD 1994k 4.9 mg kg-1 c - Belgium Reported in PSD 1994k 7.4 mg kg-1 c - Belgium Reported in PSD 1994k 7.9 mg kg-1 c - Belgium Reported in PSD 1994k 2,4-dihydroxybenzoic acid chlorfenvinphos 1.5±0.1 mg kg-1 0.02 mg kg-1 Belgium Reported in PSD 1994k

1.1 mg kg-1 c - Belgium Reported in PSD 1994k 1.3 mg kg-1 c - Belgium Reported in PSD 1994k 2,4-dihydroxybenzoic acid chlorfenvinphos 2.5 mg kg-1 c - Belgium Reported in PSD 1994k 2.0 mg kg-1 c - Belgium Reported in PSD 1994k dichlorobenzyl alcohol chlorfenvinphos 0.5 mg kg-1 c - Belgium Reported in PSD 1994k

trichloroacetophenone chlorfenvinphos 0.1 mg kg-1 - - Reported in PSD 1994k

0.41 - 0.9 ppm - UK Beynon et al. 1972b 2-chloro-4-(1-carbonyl-1- cyanazine < 0.01 - 0.08 ppm - France and UK Beynon et al. 1972a methylethylamino)-6-amino-1,3,5- triazine cyanazine acid cyanazine 0.72 - 1.66 ppm - UK Beynon et al. 1972b

80 cyanazine hydroxy acid cyanazine 0.1 - 0.79 ppm - UK Beynon et al. 1972b 2-[(4-amino-6-chloro(1,3,5-triazin- cyanazine < 0.01 - 0.02 ppm - UK Beynon et al. 1972b 2-yl))amino]-2-methylpropanenitrile (4-amino-6-chloro(1,3,5-triazin-2- cyanazine 0.03 - 0.08 ppm - UK Beynon et al. 1972b yl))ethylamine CCA cypermethrin 1-10 ng g-1 ng g-1 range Germany Class, 1992 3-phenoxybenzoic acid cypermethrin 1-10 ng g-1 ng g-1 range Germany Class, 1992 3-phenoxybenzaldehyde cypermethrin 1-10 ng g-1 ng g-1 range Germany Class, 1992 melamine cypromazine 0.05 - 1.4 mg kg-1 - Switzerland Reported in PSD 1993l ethyl-m-hydroxyphenyl carbamate desmedipham ND - 0.59 mg kg-1 0.005 mg kg-1 USA Reported in PSD 1993f o,p’-DDE DDT > 0.01 ± 0.01 µg g-1 - Australia Van Zweiten et al. 2001 p,p’-DDE DDT 17.3 ± 1.6 µg g-1 - Australia Van Zweiten et al. 2001 o,p’-DDD DDT 20.9 ± 4.9 µg g-1 - Australia Van Zweiten et al. 2001 p,p’-DDD DDT 9.0 ± 1.0 µg g-1 - Australia Van Zweiten et al. 2001 diazoxon diazinon ND 0.001 ppm UK Reported in PSD 1991b 3,6-dichlorosalicylic acid dicamba 0.05 - 1.25 µg g-1 0.005 µg g-1 USA Krueger et al. 1991 2,5-dihydroxy-3,6-dichlorosalicylic dicamba 0.03 - 0.1 µg g-1 0.005 µg g-1 USA Krueger et al. 1991 acid diclofop acid diclofop-methyl 0.01- 0.28 mg kg-1 - USA Reported in PSD 1991e DM2 diflufenican ND - 20 ± 1 µg kg-1 2 µg kg-1 Belgium Rouchaud et al. 1991 DM3 diflufenican ND - 26 ± 1 µg kg-1 2 µg kg-1 Belgium Rouchaud et al. 1991 DM4 diflufenican ND - 23 ± 1 µg kg-1 2 µg kg-1 Belgium Rouchaud et al. 1991 2,4-difluoroaniline diflufenican ND 5 µg kg-1 Belgium Rouchaud et al. 1991 3-(trifluoromethyl)phenol diflufenican ND 5 µg kg-1 Belgium Rouchaud et al. 1991 N-demethyldimefuron dimefuron 0.1 mg kg-1 b - UK Reported in PSD 1993h

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

RH-6467 fenbuconazole 5 µg kg-1 b 0.01 mg kg-1 Germany Reported in PSD 1995c 0.016 mg kg-1 0.01 mg kg-1 USA Reported in PSD 1995c 0.047 mg kg-1 b 0.01 mg kg-1 USA Reported in PSD 1995c RH-9129 fenbuconazole ND 0.01 mg kg-1 Germany Reported in PSD 1995c 0.031 mg kg-1 0.01 mg kg-1 USA Reported in PSD 1995c 0.05 mg kg-1 b 0.01 mg kg-1 USA Reported in PSD 1995c RH-9130 fenbuconazole ND 0.01 mg kg-1 Germany Reported in PSD 1995c 0.01 mg kg-1 0.01 mg kg-1 USA Reported in PSD 1995c 0.063 mg kg-1 b 0.01 mg kg-1 USA Reported in PSD 1995c fomesafen amine fomesafen <0.02 mg kg-1 0.01 mg kg-1 USA Reported in PSD 1995a 3-methyl phosphinico-proprionic glufosinate ammonium 0.03 - 0.2 mg kg-1 - Reported in PSD 1990f acid ND - 0.03 mg kg-1 < 0.05 mg kg-1 - Reported in PSD 1990f -1 -1 ©2008 AwwaRF. ALLRIGHTS RESERVED 2-hydroxyquinoxaline quinalphos ND - 64 ± 2 µg kg < 1 mg g India Menon and Gopal, 2003 quinoxaline-2-thiol quinalphos ND - 35 ± 7 µg kg-1 < 1 mg g-1 India Menon and Gopal, 2003 4-chloro-2-methylphenol MCPA 5 - 6 mg kg-1 b 15 - 45 µg kg-1 Spain Crespin et al. 2001 metolachlor ethane sulfonic acid metolachlor 11.91 - 128 µg kg-1 - USA Aga and Thurman, 2001 subsoil (30 - 60cm) 3-chlorallyl alcohol 1,3-dichloropropene ND 10 µg kg-1 USA Obreza and Ontermaa, 1991 alachlor ethane sulfonic acid alachlor 80 - 142 µg kg-1 - USA Aga and Thurman, 2001 metolachlor ethane sulfonic acid metolachlor 3.6 - 13.3 µg kg-1 - USA Aga and Thurman, 2001

81 subsoil (60 - 90cm) alachlor ethane sulfonic acid alachlor 13.3 - 140 µg kg-1 - USA Aga and Thurman, 2001 metolachlor ethane sulfonic acid metolachlor 18.7 - 122 µg kg-1 - USA Aga and Thurman, 2001

Vadose zone water alachlor ethane sulfonic acid alachlor 3 - 73 µg L-1 0.5 µg L-1 USA Aga and Thurman, 2001 deethylatrazine atrazine 0.3 µg L-1 c 0.04 µg L-1 USA Steinheimer and Scoggin, 2001 9 - 19 µg L-1 b 0.1 µg L-1 USA Fermanich et al. 1996 0.76 - 1.48 µg L-1 b 0.04 µg L-1 USA Pashin et al. 2000 15 - 29 µg L-1 b - USA Mills and Thurman, 1994 4.7 - 22.1 µg L-1 b 0.02 µg L-1 USA Adams and Thurman, 1991 deisopropylatrazine atrazine 0.6 µg L-1 c 0.04 µg L-1 USA Steinheimer and Scoggin, 2001 < 0.5 µg L-1 0.2 µg L-1 USA Fermanich et al. 1996 0.11 - 0.78 µg L-1 0.03 µg L-1 USA Pashin et al. 2000 7 - 15 µg L-1 b - USA Mills and Thurman, 1994 < 0.02 µg L-1 0.02 µg L-1 USA Adams and Thurman, 1991 didealkylatrazine atrazine 0.2 - 1.25 µg L-1 0.03 µg L-1 USA Pashin et al. 2000 hydroxyatrazine atrazine 0.08 - 0.37 µg L-1 0.04 µg L-1 USA Pashin et al. 2000 Leachate (column study) 2,6-diethylaniline alachlor 1 µg L-1 - Italy Fava et al. 2000 2-chloro-2’,6’-diethylacetanilide alachlor 2.2 - 2.7 µg L-1 - Italy Fava et al. 2000 2-hydroxy-2’,6’-diethylacetanilide alachlor 0.8 µg L-1 - Italy Fava et al. 2000 2-ethyl-6-methylaniline metolachlor 0.6 µg L-1 - Italy Fava et al. 2000

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

RH-6467 fenbuconazole trace - - Reported in PSD 1995c RH-9129 fenbuconazole trace - - Reported in PSD 1995c RH-9130 fenbuconazole trace - - Reported in PSD 1995c

Surface water runoff acetochlor oxanilic acid acetochlor ND - 0.08 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 alachlor ethane sulfonic acid alachlor ND - 48.84 µg L-1 0.5 µg L-1 USA Aga and Thurman, 2001 alachlor oxanilic acid alachlor ND - 0.17 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 deethylatrazine atrazine 0 - 10.33 µg L-1 d - France Patty et al. 1997 8 - 29 µg L-1 b 0.05 µg L-1 USA Thurman et al. 1994 0.97 µg L-1 c 0.02 µg L-1 USA Blanchard and Donald, 1997 deisopropylatrazine atrazine 0 - 12.14 µg L-1 d - France Patty et al. 1997 -1 -1 ©2008 AwwaRF. ALLRIGHTS RESERVED metolachlor ethane sulfonic acid metolachlor ND - 1.26 µg L 0.5 µg L USA Aga and Thurman, 2001 0.05 - 0.47 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 metolachlor oxanilic acid metolachlor ND - 0.29 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 tile drain deethylatrazine atrazine 0.36 - 7.71 µg L-1 0.01 µg L-1 Canada Muir and Baker, 1976 deisopropylatrazine atrazine 0.01 - 0.78 µg L-1 0.01 µg L-1 Canada Muir and Baker, 1976 cyanazine amide cyanazine < 0.04 - 3.3 µg L-1 0.01 µg L-1 Canada Muir and Baker, 1976 deisopropylatrazine cyanazine 0.02 - 0.62 µg L-1 0.01 µg L-1 Canada Muir and Baker, 1976 -1 -1 82 deethylatrazine cyprazine 0.15 - 3.6 µg L 0.01 µg L Canada Muir and Baker, 1976 metolachlor ethane sulfonic acid metolachlor 5 - > 20 µg L-1 0.2 µg L-1 USA Phillips et al. 1999 metolachlor oxanilic acid metolachlor 1 - 10 µg L-1 0.2 µg L-1 USA Phillips et al. 2002 ditch 2-isoprpyl-6-methyl-4- diazinon ND 1 µg L-1 Canada Li et al. 2002 hydroxypyrimidine diazioxon diazinon ND 0.03 µg L-1 Canada Li et al. 2002 stream acetochlor ethane sulfonic acid acetochlor < 0.2 - 1.6 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 acetochlor oxanilic acid acetochlor < 0.02 - 1.4 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 2,6-diethylanaline alachlor ND 0.01 µg L-1 USA Hoffman et al. 2000 alachlor ethane sulfonic acid alachlor < 0.2 - 3.5 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 alachlor ethane sulfonic acid alachlor 0.8 - 5.2 µg L-1 c 0.1 µg L-1 USA Kolpin et al. 1996a 5.2 - 27.8 µg L-1 b 0.1 µg L-1 USA Kolpin et al. 1996a alachlor oxanilic acid alachlor < 0.2 - 0.54 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 aldicarb sulfone aldicarb ND 0.05 µg L-1 USA Hoffman et al. 2000 aldicarb sulfoxide aldicarb ND 0.05 µg L-1 USA Hoffman et al. 2000 deethylatrazine atrazine and propazine < 0.05 - 0.39 µg L-1 0.05 µg L-1 USA Kalkhoff et al. 2003

stream continued deethylatrazine continued atrazine and propazine 0.04 µg L-1 b 0.01 µg L-1 USA Hoffman et al. 2000 deisopropylatrazine atrazine, cyanazine and < 0.05 - 0.36 µg L-1 0.05 µg L-1 USA Kalkhoff et al. 2003 simazine

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

hydroxyatrazine atrazine < 0.2 - 8.8 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 cyanazine amide cyanazine < 0.05 - 1.2 µg L-1 0.05 µg L-1 USA Kalkhoff et al. 2003 3-hydroxycarbofuran carbofuran ND 0.05 µg L-1 USA Hoffman et al. 2000 p,p’-DDE DDT ND 0.01µg L-1 USA Hoffman et al. 2000 alpha-HCH gamma-HCH ND 0.01 µg L-1 USA Hoffman et al. 2000 metolachlor ethane sulfonic acid metolachlor < 0.2 - 6.7 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 < 0.2 - 0.57 µg L-1 0.2 µg L-1 USA Phillips et al. 1999 metolachlor oxanilic acid metolachlor < 0.2 - 1.3 µg L-1 0.2 µg L-1 USA Kalkhoff et al. 2003 < 0.2 - > 0.5 µg L-1 0.2 µg L-1 USA Phillips et al. 1999 trifluoromethylphenyl urea fluometuron ND 0.05 µg L-1 USA Coupe et al. 1998 deisopropylprometryn prometryn ND 0.05 µg L-1 USA Coupe et al. 1998 -1 -1

©2008 AwwaRF. ALLRIGHTS RESERVED 3,4-dichloroaniline propanil 0.9 µg L 0.05 µg L Coupe et al. 1998 river 2,4-dichlorophenol 2,4-D ND 75 ng L-1 Italy Lagana et al. 2002 acetochlor oxanilic acid acetochlor ND - 0.15 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 alachlor ethane sulfonic acid alachlor 1.55 - 4.75 µg L-1 c 0.1 µg L-1 USA Battaglin and Goolsby, 1999 2.1 µg L-1 0.05 µg L-1 USA Verstraeten et al. 1999 alachlor oxanilic acid alachlor ND - 0.21 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 -1 -1 83 2,6-diethylaniline alachlor ND - 0.924 µg L 5 ng L USA Pereira and Rostad, 1990 2-chloro-2’,6’-diethylacetanilide alachlor ND - 0.35 µg L-1 5 ng L-1 USA Pereira and Rostad, 1990 2-hydroxy-2’,6’-diethylacetanilide alachlor ND - 0.9 µg L-1 5 ng L-1 USA Pereira and Rostad, 1990 8-hydroxy-bentazone bentazone ND - 27 µg L-1 2 ng L-1 Italy Lagana et al. 2002 cyanazine amide cyanazine 0.47 - 0.57 µg L-1 c 0.05 µg L-1 USA Battaglin and Goolsby, 1999 0.06 µg L-1 c 0.02 µg L-1 USA Lerch and Blanchard, 2003 ND - 222 ng L-1 25 ng L-1 USA Pereira and Hostettler, 1993 deethylcyanazine cyanazine < 0.05 µg L-1 c 0.05 µg L-1 USA Battaglin and Goolsby, 1999 ND 0.05 µg L-1 USA Verstraeten et al. 1999 deethylcyanazine amide cyanazine < 0.05 µg L-1 c 0.5 µg L-1 USA Battaglin and Goolsby, 1999 deethylatrazine atrazine and propazine 0.42 - 0.47 µg L-1 c 0.05 µg L-1 USA Battaglin and Goolsby, 1999 0.39 - 4.4 µg L-1 b 0.05 µg L-1 USA Thurman et al. 1992 ND - 0.407 µg L-1 0.005 µg L-1 Greece Albanis et al. 1998 ND - 0.215 µg L-1 0.01 µg L-1 Greece Albanis and Hela, 1998 0.025 - 0.08 µg L-1 0.3 ng L-1 USA Sabik et al. 2003 7 - 82 ng L-1 5 ng L-1 USA Pereira and Rostad, 1990 5 - 855 ng L-1 5 ng L-1 USA Pereira and Hostettler, 1993 150 ng L-1 b 1 ng L-1 USA Liu et al. 2002 12 - 28 µg L-1 c - USA Reported in Solomon et al. 1996 deisopropylatrazine atrazine, cyanazine and 0.43 - 0.87 µg L-1 c 0.05 µg L-1 USA Battaglin and Goolsby, 1999 simazine < 0.05 - 3.2 µg L-1 b 0.05 µg L-1 USA Thurman et al. 1992

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

0.007 - 0.038 µg L-1 0.3 ng L-1 USA Sabik et al. 2003 8 - 45 ng L-1 5 ng L-1 Pereira and Rostad, 1990 ND - 335 ng L-1 10 ng L-1 USA Pereira and Hostettler, 1993 64 ng L-1 b 1.8 ng L-1 USA Liu et al. 2002 4.9 - 15 µg L-1 c - USA Reported in Solomon et al. 1996 p,p’-DDE DDT 4 ng L-1 b 0.3 ng L-1 USA Liu et al. 2002 dimethenamid ethane sulfonic acid dimethenamid 0.05 µg L-1 c 0.03 µg L-1 USA Zimmerman et al. 2002 dimethenamid oxanilic acid dimethenamid 0.05 µg L-1 c 0.02 µg L-1 USA Zimmerman et al. 2002 flufenacet ethane sulfonic acid flufenacet 0.06 µg L-1 c 0.01 µg L-1 USA Zimmerman et al. 2002 flufenacet oxanilic acid flufenacet 0.05 µg L-1 c 0.07 µg L-1 USA Zimmerman et al. 2002 4-chloro-2-methylphenol MCPA ND 50 ng L-1 Italy Lagana et al. 2002 ©2008 AwwaRF. ALLRIGHTS RESERVED metolachlor oxanilic acid metolachlor ND - 0.29 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 metolachlor ethane sulfonic acid metolachlor 0.33 - 1.82 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 endosulfan sulphate endosulfan 6 ng L-1 0.3 ng L-1 USA Liu et al. 2002 canal deethylatrazine atrazine ND - 0.526 0.01 µg L-1 Greece Albanis and Hela, 1998 lake -1 b -1

84 deethylatrazine atrazine 1.57 µg L 0.05 µg L USA Spalding et al. 1994 92 ng L-1 c 2 - 6 ng L-1 Switzerland Bucheli et al. 1997 0.36 µg L-1 c 0.05 µg L-1 USA Thurman et al. 2000 0.18 - 1.57 µg L-1 b 0.05 µg L-1 USA Spalding et al. 1994 0.1 - 0.54 µg L-1 c deisopropylatrazine atrazine 1.06 µg L-1 b 0.09 µg L-1 USA Spalding et al. 1994 26 ng L-1 c 2 - 6 ng L-1 Switzerland Bucheli et al. 1997 ND - 1.06 µg L-1 b 0.09 µg L-1 USA Spalding et al. 1994 ND - 0.92 µg L-1 c hydroxyatrazine atrazine 0.56 µg L-1 c 0.05 µg L-1 USA Thurman et al. 2000 dichlorophenylurea diuron 0.2 µg L-1 c 0.2 µg L-1 USA Thurman et al. 2000 dichloromethylphenylurea diuron 0.45 µg L-1 c 0.2 µg L-1 USA Thurman et al. 2000 3,4-dichloroaniline diuron 0.31 µg L-1 c 0.05 µg L-1 USA Thurman et al. 2000 metolachlor ethane sulfonic acid metolachlor 0.1 µg L-1 c 0.2 µg L-1 USA Thurman et al. 2000 metolachlor oxanilic acid metolachlor 0.19 µg L-1 c 0.2 µg L-1 USA Thurman et al. 2000 demethylnorflurazon norflurazon 0.17 µg L-1 c 0.05 µg L-1 USA Thurman et al. 2000

Groundwater 2,4-dichlorophenol 2,4-D 4 µg L-1 b - Denmark Helweg et al. 2002 acetochlor ethane sulfonic acid acetochlor 0.77 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 3.32 µg L-1 0.2 µg L-1 USA Boyd, 2000 acetochlor ethane sulfonic acid acetochlor 0.28 µg L-1 c 0.1 µg L-1 USA Kolpin et al. 1996a 8.6 µg L-1 b 0.1 µg L-1 USA Kolpin et al. 1996a

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

acetochlor oxanilic acid acetochlor 11.5 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 1.75 µg L-1 0.2 µg L-1 USA Boyd, 2000 ND - 0.17 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 α-N-[(2'-6'- alachlor < 2 - 480 ng L-1 - USA Potter and Carpenter, 1995 diethylphenylamino]ethanol 2-chloro-2'-ethyl-6'-ethyl-N- alachlor < 2 - 310 ng L-1 - USA Potter and Carpenter, 1995 (methoxymethyl)acetanilide 2'-acetyl-6'-ethylacetanilide alachlor 28 - 120 ng L-1 - USA Potter and Carpenter, 1995 2'-acetyl-6'-ethyl-N- alachlor 68 - 240 ng L-1 - USA Potter and Carpenter, 1995 methoxymethyl)acetanilide 2-hydroxy-2',6'-diethyl-N- alachlor < 2 - 130 ng L-1 - USA Potter and Carpenter, 1995 methyl)acetanilide 2-hydroxy-2',6'-diethyl-N- alachlor < 2 - 100 ng L-1 - USA Potter and Carpenter, 1995 ©2008 AwwaRF. ALLRIGHTS RESERVED methoxymethyl)acetanilide 2,6-diethylaniline alachlor 0.085 µg L-1 b 0.003 µg L-1 USA Kolpin et al. 1998 < 2 - 16 ng L-1 - USA Potter and Carpenter, 1995 0.02 µg L-1 b 0.02 µg L-1 USA Kolpin et al. 1996b 2',6'-diethylacetanilide alachlor < 2 - 130 ng L-1 - USA Potter and Carpenter, 1995 2',6'-diethylformanilide alachlor < 2 - 87 ng L-1 - USA Potter and Carpenter, 1995 7-ethylindoline alachlor < 2 - 35 ng L-1 - USA Potter and Carpenter, 1995 85 alachlor ethane sulfonic acid alachlor 1.2 µg L-1 b 0.05 µg L-1 USA Verstraeten et al. 1999 8.63 µg L-1 b 0.1 µg L-1 USA Kolpin et al. 1996b 8.5 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 2.5 µg L-1 0.2 µg L-1 USA Boyd, 2000 0.06 - 9.32 µg L-1 0.05 µg L-1 USA Aga et al. 1994 alachlor oxanilic acid alachlor 33.4 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 0.31 µg L-1 0.2 µg L-1 USA Boyd, 2000 0.02 - 1.66 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 N-(2,6-diethylphenyl) methylene alachlor < 2 - 10 ng L-1 - USA Potter and Carpenter, 1995 N-(2,6-diethylphenyl)-N- alachlor 100 - 550 ng L-1 - USA Potter and Carpenter, 1995 (methoxymethyl)acetamide deethylatrazine atrazine 0.205 µg L-1 b 1 - 5 ng L-1 Greece Albanis et al. 1998 0.4 µg L-1 c 0.04 µg L-1 USA Steinheimer and Scoggin, 2001 2.32 µg L-1 b 0.05 µg L-1 USA Burkart and Kolpin, 1993 7 ng L-1 - Switzerland Bucheli et al. 1997 deethylatrazine continued atrazine 2.6 µg L-1 b 0.002 µg L-1 USA Kolpin et al. 1998 5 µg L-1 0.02 µg L-1 USA Adams and Thurman, 1991 2.2 µg L-1 b 0.05 µg L-1 USA Kolpin et al. 1996b 0.59 µg L-1 b 0.05 µg L-1 USA Kolpin et al. 2000 ND - 0.44 µg L-1 0.05 µg L-1 USA Boyd, 2000 0.05 - 0.13 µg L-1 b 0.02 µg L-1 USA Blanchard and Donald, 1997

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

deisopropylatrazine atrazine 0.6 µg L-1 c 0.04 µg L-1 USA Steinheimer and Scoggin, 2001 deisopropylatrazine atrazine, cyanazine, 1.17 µg L-1 b 0.05 µg L-1 USA Kolpin et al. 1996b simazine 14 ng L-1 - Switzerland Bucheli et al. 1997 < 0.02 µg L-1 0.02 µg L-1 USA Adams and Thurman, 1991 1.1 µg L-1 b 0.05 µg L-1 USA Kolpin et al. 2000 ND - 0.26 µg L-1 0.05 µg L-1 USA Boyd, 2000 hydroxyatrazine atrazine 1.3 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 0.22 µg L-1 0.2 µg L-1 USA Boyd, 2000 cyanazine amide cyanazine 0.55 µg L-1 b 0.55 µg L-1 USA Kolpin et al. 1996b 0.64 µg L-1 b 0.05 µg L-1 USA Kolpin et al. 2000 ©2008 AwwaRF. ALLRIGHTS RESERVED ND - 0.31 µg L-1 0.05 µg L-1 USA Boyd, 2000 deethylcyanazine cyanazine ND 0.05 µg L-1 USA Verstraeten et al. 1999 ND 0.05 µg L-1 USA Kolpin et al. 1996b deethylcyanazine amide cyanazine ND 0.05 µg L-1 USA Kolpin et al. 1996b dacthal mono acid and diacid dacthal ND - 158.2 µg L-1 e 0.05 µg L-1 USA Monohan et al. 1995 dacthal diacid dacthal 2.22 µg L-1 b 0.01 µg L-1 USA Kolpin et al. 1996b p,p’-DDE DDT 0.006 µg L-1 b 0.006 µg L-1 USA Kolpin et al. 1998 86 0.03 µg L-1 b 0.03 µg L-1 Kolpin et al. 1996b AMPA glyphosate 1.6 µg L-1 b - Denmark Helweg et al. 2002 α-HCH lindane 0.059 µg L-1 b 0.002 µg L-1 USA Kolpin et al. 1998 metolachlor ethane sulfonic acid metolachlor 8.6 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 6.84 µg L-1 0.2 µg L-1 USA Boyd, 2000 metolachlor ethane sulfonic acid metolachlor 0.1 - 1.83 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997 continued metolachlor oxanilic acid metolachlor 15.3 µg L-1 b 0.2 µg L-1 USA Kolpin et al. 2000 ND - 4.25 µg L-1 0.2 µg L-1 USA Boyd, 2000 0.03 - 0.91 µg L-1 0.01 µg L-1 USA Ferrer et al. 1997

Raw source water reservoir deethylatrazine atrazine 0.14 - 0.24 µg L-1 c - USA Reported in Solomon et al. 1996 0.38 µg L-1 c - USA Reported in Solomon et al. 1996 deisopropylatrazine atrazine 0.08 - 0.14 µg L-1 c - USA Reported in Solomon et al. 1996 0.1 µg L-1 c - USA Reported in Solomon et al. 1996 hydroxyatrazine atrazine 0.8 µg L-1 c - USA Reported in Solomon et al. 1996 azinphos-methyl-oxon azinphos-methyl 0.263 µg L-1 c 0.031 µg L-1 USA Reported in Nguyen et al, 2004

Environmental Degradate Parent pesticide a Concentration Limit of detection Country Reference compartment

disulfoton sulfone disulfoton 0.013 µ g L-1 c 0.005 µg L-1 USA Reported in Nguyen et al, 2004 disulfoton sulfoxide disulfoton 0.06 µg L-1 c 0.016 µg L-1 USA Reported in Nguyen et al, 2004 fenamiphos sulfone fenamiphos 0.005 µg L-1 c 0.008 µg L-1 USA Reported in Nguyen et al, 2004 fenamiphos sulfoxide fenamiphos 0.021 µg L-1 c 0.008 µg L-1 USA Reported in Nguyen et al, 2004 malaoxon malathion ND 0.005 µg L-1 USA Reported in Nguyen et al, 2004 abstraction wells o-p’-DDA DDT 0.28 µg L-1 - Germany Reported in Heberer and Dünnbier, 1999 p-p’-DDA DDT 1.7 µg L-1 - Germany Reported in Heberer and Dünnbier, 1999

Finished drinking water ©2008 AwwaRF. ALLRIGHTS RESERVED azinphos-methyl-oxon azinphos-methyl 0.026 µg L-1 c 0.031 µg L-1 USA Reported in Nguyen et al, 2004 disulfoton sulfone disulfoton ND 0.005 µg L-1 USA Reported in Nguyen et al, 2004 disulfoton sulfoxide disulfoton ND 0.016 µg L-1 USA Reported in Nguyen et al, 2004 fenamiphos sulfone fenamiphos 0.011 µg L-1 c 0.008 µg L-1 USA Reported in Nguyen et al, 2004 fenamiphos sulfoxide fenamiphos 0.022 µg L-1 c 0.008 µg L-1 USA Reported in Nguyen et al, 2004 malaoxon malathion 0.106 µg L-1 c 0.005 µg L-1 USA Reported in Nguyen et al, 2004

a - pesticide identified in the reference as the source of the degradate b - peak concentration during study c - median or mean concentration d - calculated average concentration e - combined degradate concentration

APPENDIX 5. ADI FOR PESTICIDES

Pesticide ADI Region Source chlorpropham 0.1 mg kg-1 bw day-1 (temporay) UK Reported in PSD 1993k cyromazine 0.015 mg kg-1 bw day-1 UK Reported in PSD 1993l desmedipham 0.0018 mg kg-1 bw day-1 UK Reported in PSD 1993f diclofop-methyl 0.001 mg kg-1 bw day-1 UK Reported in PSD 1991e difenoconazole 0.01 mg kg-1 bw day-1 UK Reported in PSD 1994j dimefuron 0.06 mg kg-1 bw day-1 UK Reported in PSD 1993h dimethoate 0.0008 mg kg-1 bw day-1 UK Reported in PSD 1993j dimethomorph 0.05 mg kg-1 bw day-1 UK Reported in PSD 1994g epoxiconazole 0.01 mg kg-1 bw day-1 UK Reported in PSD 1994l esfenvalerate 0.003 mg kg-1 bw day-1 UK Reported in PSD 1992b fenbuconazole 0.01 mg kg-1 bw day-1 UK Reported in PSD 1995c fenpiclonil 0.23 mg kg-1 bw day-1 UK Reported in PSD 1993g fenpyroximate 0.01 mg kg-1 bw day-1 UK Reported in PSD 1995d fluazinam 0.006 mg kg-1 bw day-1 UK Reported in PSD 1994h fludioxonil 0.01 mg kg-1 bw day-1 UK Reported in PSD 1995b fluoroglycofen-ethyl 0.0095 mg kg-1 bw day-1 UK Reported in PSD 1992a fomesafen 0.003 mg kg-1 bw day-1 UK Reported in PSD 1995a imazaquin 0.3 mg kg-1 bw day-1 UK Reported in PSD 1993a imidacloprid 0.03 mg kg-1 bw day-1 UK Reported in PSD 1993e mecoprop 0.01 mg kg-1 bw day-1 UK Reported in PSD 1994d mecoprop-P 0.01 mg kg-1 bw day-1 UK Reported in PSD 1994e

ADI - Acceptable daily intake

APPENDIX 6. MAMMALIAN ACUTE, SUBACUTE AND SUBCHRONIC DATA FOR PESTICIDE DEGRADATES

Degradate Parent pesticide Species Administration Toxicity a End-point Concentration Source (mg kg-1 body weight)

aldicarb nitrile aldicarb rat oral LD50 570 Reported in PSD 1994m aldicarb sulphoxide aldicarb rat oral LD50 0.49 - 1.13 Reported in PSD 1994m rat ip LD50 0.47 Reported in PSD 1994m rat ip LD50 0.71 Reported in PSD 1994m rat iv LD50 0.47 Reported in PSD 1994m rat oral subacute/ sub chronic NOAEL 0.4 mg kg bw-1 day-1 Reported in PSD 1994m rat oral subacute/ sub chronic NOEL 0.125 mg kg bw-1 day-1 Reported in PSD 1994m mouse oral LD50 0.8 - 1.6 Reported in PSD 1994m ©2008 AwwaRF. ALLRIGHTS RESERVED guinea pig oral LD50 0.8 - 1.8 Reported in PSD 1994m rabbit oral LD50 0.4 - 1.8 Reported in PSD 1994m rabbit dermal LD50 > 20 Reported in PSD 1994m dog oral NOEL 0.25 mg kg bw-1 day-1 Reported in PSD 1994m aldicarb sulfone aldicarb rat oral LD50 20 - 25 Reported in PSD 1994m rat oral subacute/ sub chronic NOAEL 2.5 mg kg bw-1 day-1 Reported in PSD 1994m rat ip LD50 21.2 Reported in PSD 1994m rat iv LD50 14.9 Reported in PSD 1994m 91 mouse oral LD50 25 Reported in PSD 1994m guinea pig oral LD50 > 50 Reported in PSD 1994m rabbit oral LD50 75 Reported in PSD 1994m rabbit dermal LD50 > 20 Reported in PSD 1994m dog oral subacute/ sub chronic NOEL 5.4 mg kg bw-1 day-1 Reported in PSD 1994m dog oral subacute/ sub chronic NOAEL 0.125 mg kg bw-1 day-1 Reported in PSD 1994m -1 aldicarb oxime aldicarb rat inhalation LD50 1.56 mg L Reported in PSD 1994m 2-methyl-2-(methyl aldicarb rat oral LD50 11000 Reported in PSD 1994m sulphinyl) propanol -1 hydroxyl-methyl aldicarb rat oral LD50 42.9 Reported in PSD 1994m aldicarb aldicarb sulphoxide aldicarb rat oral LD50 8060 Reported in PSD 1994m oxime aldicarb sulphone aldicarb rat oral LD50 1590 Reported in PSD 1994m oxime aldicarb sulphoxide aldicarb rat oral LD50 4000 Reported in PSD 1994m nitrile aldicarb sulphone aldicarb rat oral LD50 350 Reported in PSD 1994m nitrile 2-amino-4,6- amidosulfuron rat oral LD50 2700 Reported in PSD 1994a dimethoxypyrimidine 2-amino-4,6- amidosulfuron rat oral LD50 > 5000 Reported in PSD 1994a dihydroxypyrimidine HOE 101630 amidosulfuron rat oral LD50 > 5000 Reported in PSD 1994a (4,6- amidosulfuron rat oral LD50 > 5000 Reported in PSD 1994a dihydroxypyrimidin-2-

Degradate Parent pesticide Species Administration Toxicity a End-point Concentration Source (mg kg-1 body weight) yl deethylatrazine atrazine rat oral LD50 496 - 2480 Reported in PSD 1993d Reported in PSD 1993d deisopropylatrazine atrazine rat oral LD50 338 - 2800 Reported in PSD 1993d deisopropyl atrazine rat oral LD50 > 5050 Reported in PSD 1993d deethylatrazine dog oral subacute NTEL 3.5 mg kg bw-1 day-1 Reported in PSD 1993d hydroxyatrazine atrazine rat oral LD50 > 5050 Reported in PSD 1993d rat oral subacute NTEL 6.3 - 7.35 mg kg bw-1 day-1 Reported in PSD 1993d dog oral subacute NTEL 5.8 - 6.2 mg kg bw-1 day-1 Reported in PSD 1993d melamine cypromazine mouse oral LD50 3296 - 7014 Reported in PSD1993l mouse oral subacute NOEL 1800 mg kg bw-1 day-1 Reported in PSD1993l mouse oral subacute NOEL 900 mg kg bw-1 day-1 Reported in PSD1993l rat oral 3161 - 3828 Reported in PSD1993l -1 -1 ©2008 AwwaRF. ALLRIGHTS RESERVED rat oral subacute NOEL 250 - 300 mg kg bw day Reported in PSD1993l b dinitro octyl phenol dinocap mouse oral LD50 96 Reported in PSD1991a mouse oral LD50 122 Reported in PSD1991a 2,4-dinitro-6-(2-octyl) dinocap rat oral LD50 249 Reported in PSD1991a phenol rat oral LD50 211 Reported in PSD1991a mouse oral LD50 194 Reported in PSD1991a mouse oral LD50 154 Reported in PSD1991a

92 mouse oral LD50 > 150 Reported in PSD1991a 2,6-dinitro-4-(2-octyl) dinocap rat oral LD50 583 Reported in PSD1991a phenol rat oral LD50 318 Reported in PSD1991a mouse oral LD50 267 Reported in PSD1991a mouse oral LD50 271 Reported in PSD1991a fluazifop acid fluazifop-butyl rat percutaneous LD50 > 5000 Reported in PSD 1988a 2-(4-hydroxy rat oral LD50 > 5000 Reported in PSD 1988a phenoxy) propionic acid 5-trifluoro-methyl- rat oral LD50 3417 - 3866 Reported in PSD 1988a pyrid-2-one triazole acetic acid flusilazole rat oral LD50 > 5000 Reported in PSD 1989a mecoprop-hydroxy mecoprop rat oral LD50 > 2150 Reported in PSD 1994d a - acute toxicity unless otherwise stated b - isomer not defined LC50 - lethal concentration (50%) LD50 - lethal dose (50%) LOAEL - lowest observed adverse effect level MEL - minimum effect level NOAEC - no observed adverse effect concentration NOAEL - no observed adverse effect level NOEC - no observed effect concentration NOEL - no observed effect level NTEL - no toxicological effect level

APPENDIX 7. DEGRADATE ABBREVIATIONS USED IN THE DATA APPENDICES

Where a degradate was not given a chemical name only represented structurally in the reference, the chemical name (IUPAC) was obtained by drawing the structure in ChemDraw Std. Ver. 8.0 (CambridgeSoft Corporation, 2003) and naming the compound using the add-on Nomenclator Ver 6.0 (ChemInnovation Software, 2001).

210 352 [3-(2-chlorophenyl)-2-(4-fluorophenyl)oxiran-2-yl]methan-1-ol 231 761 1-(2-chlorophenyl)-2-(4-fluorophenyl)-3-(1,2,4-triazolyl)propane-1,2-diol 4’-OH-fen (1S)cyano[3-(4-hydroxyphenoxy)phenyl]methyl (2R)-2-(4-chlorophenyl)-3- methylbutanoate buprofezin metabolite 9 3-isopropyl-5-phenyl-3,4,5,6-tetrahydro-2H-1,3,5-thiadiazinone-2,4-dione carbinol N-(2-ethyl-6-methylphenyl)-2-hydroxy-N-(2-methylethyl)-acetamide CCA 2,2-dimethyl-3-(1,1-dichlorovinyl) cyclopropane carboxylic acid CGA 189138 2-chloro-4-(4-chlorophenoxy)benzoic acid CGA 205374 1-[2-chloro-4-(4-chlorophenoxy)phenyl]-2-(1,2,4-triazolyl)ethan-1-one CGA 205375 1-[2-chloro-4-(4-chlorophenoxy)phenyl]-2-(1,2,4-triazolyl)ethan-1-ol CGA 257 777 4-(2,2-difluorobenzo[d]1,3-dioxolen-4-yl)pyrrole-3-carboxylic acid Cl-Vacid (2R,3R)-2-(4-chlorophenyl)-2,4-dihydroxy-3-methylbutanoic acid compound B ({3-chloro-4-[5-(2-hydroxy-tert-butyl)-2-oxo(1,3,4-oxadiazolin-3- yl)]phenyl}amino)-N-methylcarboxamide compound C ({3-chloro-4-[5-(2-hydroxy-tert-butyl)-2-oxo(1,3,4-oxadiazolin-3- yl)]phenyl}amino)-N,N-dimethylcarboxamide compound D amino-N-{4-[5-(tert-butyl)-2-oxo(1,3,4-oxadiazolin-3-yl)]-3- chlorophenyl}amide compound G N-({4-[(N,N-dimethylcarbamoyl)amino]-2-chlorophenyl}amino)-2,2- dimethylpropanamide compound V 5-chloro-6-(3-chloro-α,α,α-trifluoro-2,6-dinitro-p-toluidine)-nicotinic acid compound VII 2-chloro-6-(3-chlotro-5-trifluoromethyl-2-pyridylamino)-α,α,α-trifluoro-5- nitro-m-toluidine compound VIII 4-chloro-2-(3-chloro-5-trifluoromethyl-2-pyridyl)amino-5-trifluoromethyl-m- phenylenediamine compound XII 5-(3-chloro-5-trifluoromethyl-2-pyridyl-amino) -α,α,α-trifluoro-4,6-dinitro-o- cresol CONH2-fen (1S)carbamoyl(3-phenoxyphenyl)methyl (2R)-2-(4-chlorophenyl)-3- methylbutanoate COOH-fen no structure identified in the reference cyanazine acid 2-{[4-chloro-6-(ethylamino)(1,3,5-triazin-2-yl)]amino}-2-methylpropanoic acid cyanazine amide 2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-ethylamino-1,3,5-triazine cyanazine hydroxy acid 2-{[6-(ethylamino)-4-hydroxy(1,3,5-triazin-2-yl)]amino}-2-methylpropanoic acid dec-fen no structure identified in the reference DEHA 6-hydroxy-N-isopropyl-1,3,5-triazin-2-ylamine DIHA N-ethyl-6-hydroxy-1,3,5-triazin-2-ylamine DM2 2-[3-(trifluoromethyl)phenoxy]pyridine-3-carboxylic acid DM3 N-(2,4-difluorophenyl)(2-hydroxy(3-pyridyl))carboxamide DM4 2-hydroxypyridine-3-carboxylic acid DPX M6316 TP1 methyl 2-(4-methoxy-6-methyl-1,3,5-triazin-2-yl-amino)-3-thiophene- carboxylate F0 12-7124 (RS)-1-[3-(4-tert-butylphenyl)-2-methylpropyl piperidin-1-oxide F0 18-5445 (RS)-1-[3-(4-tert-butylphenyl)-2-methylpropyl piperidin-4-ol

©2008 AwwaRF. ALL RIGHTS RESERVED fomesafen amine {2-amino-5-[2-chloro-4-(trifluoromethyl)phenoxy]phenyl}-N- (methylsulfonyl)carboxamide fomesafen amino acid 2-amino-5-[2-chloro-4-(trifluoromethyl)phenoxy]benzoic acid fomesafen nitro acid 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid HOE 070542 ethyl-1-(2,4-dichlorophenyl)-5-trichloromethyl-(1H)-1,2,4-triazole-3- carboxylate HOE 101630 3-(4-hydroxy-6-methoxypyrimidin-2-yl)-1-(N-methyl-N-methylsulfonyl- aminosulfonyl)-urea HOE 35956 2-amino-4-(methyl(hydroxyphosphoryl))butanoic acid HOE 64619 2-(methyl(hydroxyphosphoryl))acetic acid HOE 65594 4-(methyl(hydroxyphosphoryl))-2-oxobutanoic acid HOE 72829 1-(2,4-dichlorophenyl)-5-trichloromethyl-(1H)-1,2,4-triazole-3-carboxylic acid HOE 83348 1-(2,4-dichlorophenyl)-(1H)-1,2,4-triazole-3-carboxylic acid HOE 85355 2-(acetylamino)-4-(methyl(hydroxyphosphoryl))butanoic acid HOE 86486 3-(methyl(hydroxyphosphoryl))-3-oxopropanoic acid HOE 87606 ethyl-(2,4-dichlorophenyl)-5-chloromethyl-(1H)-1,2,4-triazole-3-carboxylate HOE 88988 1-(2,4-dichlorophenyl)-5-chloromethyl-(1H)-1,2,4-triazole-3-carboxylic acid HOE 88989 1-(2,4-dichlorophenyl)-5-dichloromethyl-(1H)-1,2,4-triazole-3-carboxylic acid HOE 89628 1-(2,4-dichlorophenyl)-5-hydroxy-(1H)-1,2,4-triazole-3-carboxylic acid Ia (1RS)-cis-3-(ZE-2 chloro-3,3,3-trifluoroprop-1-enyl)-2,2- dimethylcyclopropanecarboxylic acid Ib (1RS)-trans-3-(ZE-2 chloro-3,3,3-trifluoroprop-1-enyl)-2,2- dimethylcyclopropanecarboxylic acid M1 2-[N-(1-carbamoyl-1,2-dimethylpropyl)carbamoyl]quinoline-3-carboxylic acid M3 (E)-4-[(1,3-dimethyl-5-phenoxypyrazol-4-yl)-methyleneaminooxy-methyl] benzoic acid morpholinone 4-(2-ethyl-6-methylphenyl)-5-methyl-3-morpholinone R0 15-6045 1-[3-(p-2-hydroxymethylisopropyl)phenyl-2-methylpropyl] piperidine RH-0265-NH2 ethyl 2-{2-amino-5-[2-chloro-4- (trifluoromethyl)phenoxy]phenylcarbonyloxy}acetate RH-4514 2-amino-5-[2-chloro-4-(trifluoromethyl)phenoxy]benzoic acid RH-4515 2-(acetylamino)-5-[2-chloro-4-(trifluoromethyl)phenoxy]benzoic acid RH-5349 presented as structurally identical to RH-5781 RH-5781 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid RH-5782 methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate RH-6467 4-(4-chlorophenyl)-4-oxo-2-phenyl-2-(1,2,4-triazolylmethyl)butanenitrile RH-670 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrophenol RH-9129 (5S,3R)-5-(4-chlorophenyl)-3-phenyl-3-(1,2,4-triazolylmethyl)-3,4,5- trihydrofuran-2-one RH-9130 (3S,5S)-5-(4-chlorophenyl)-3-phenyl-3-(1,2,4-triazolylmethyl)-3,4,5- trihydrofuran-2-one RH-9985 2-{5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrophenylcarbonyloxy}acetic acid SD 53065 no structure identified in the reference SDS 1449 monomethyltetrachloroterephthalate SDS 954 tetrachloroterephthalic acid TDTP 1,6,7,8-tetrahydro-7,7-dimethyl-3-[p-(trifluoromethyl)-styryl]-4H-pyrimido [2,1-c]-as-triazo-4-one

• degradates where at least one default value was required in the prioritization are represented in italics • ■ = experimental regulatory data available, □ = default value used in the prioritisation

Pesticide Degradate Formation Kd DT50 ADI RI

alachlor 2,6-diethyl-N-methoxymethyl-2-sulpho-acetanilide ■ □ □ ■ 47.58 ©2008 AwwaRF. ALLRIGHTS RESERVED alachlor alachlor oxanilic acid ■ □ □ ■ 42.63 alachlor 2,6-diethyl-N-methoxy-methoxanilic acid ■ □ □ ■ 41.87 cyanazine cyanazine acid □ ■ □ ■ 35.95 alachlor alachlor ethane sulfonic acid ■ ■ □ ■ 33.33 acetochlor 2-([N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)carbomyl]methylsulfonyl) acetic acid □ □ □ ■ 33.30

95 acetochlor acetochlor oxanilic acid □ □ □ ■ 33.30 acetochlor N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide □ □ □ ■ 33.30 acetochlor N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-2-sulfoneacetamide □ □ □ ■ 33.30 cyanazine cynazine amide □ ■ □ ■ 32.62 alachlor alachlor DM-oxanilic acid ■ □ □ ■ 32.35 alachlor alachlor sulfinylacetic acid ■ □ □ ■ 30.83 alachlor 2',6'-diethyl-2-hydroxy-N-methoxymethylacetanilide ■ □ □ ■ 19.41 atrazine DEHA ■ □ □ ■ 13.96 atrazine deisopropyl atrazine ■ ■ □ ■ 11.27 atrazine DIHA ■ □ □ ■ 9.90 atrazine diaminochloroatrazine ■ ■ □ ■ 7.88 dichloropropene 3-chloroprop-2-enoic acid □ □ □ ■ 7.61 dicamba 3,6-dichlorosalicylic acid ■ ■ □ ■ 7.24 2,4-D 1,2,4-benzenetriol □ □ □ ■ 6.28

atrazine hydroxy atrazine ■ ■ ■ ■ 2.51 malathion malathion dicarboxylic acid ■ □ ■ ■ 2.43

Pesticide Degradate Formation Kd DT50 ADI RI

metolachlor metolachlor oxanilic acid ■ □ □ ■ 2.23 chlorothalonil 3-cyano-2,4,5,6-tetrachlorobenzamide ■ □ □ ■ 1.69 trifluralin a,a,a-trifluoro-2,6-dinitro-N-propyl-p-toluidine ■ □ □ ■ 1.34 metolachlor CGA-37735 ■ □ □ ■ 1.18 chlorothalonil 3-carbamyl-1,2,4,5-tetrachlorobezoic acid ■ □ □ ■ 0.99 trifluralin 2,2'-azoxybis (a,a,a-trifluoro-6-nitro-N-propyl-p-toluidine ■ □ □ ■ 0.88 trifluralin a,a,a-trifluoro-2,6-dinitro-p-cresol ■ □ □ ■ 0.79 trifluralin 2-ethyl-7-nitro-5-(trifluoromethyl) benzimidazole ■ □ □ ■ 0.76 ©2008 AwwaRF. ALLRIGHTS RESERVED chlorpyrifos 3,5,6-chloro-2-pyridinol ■ ■ ■ ■ 0.74 ethephon 2-hydroxy ethyl phosphonic acid ■ □ □ ■ 0.73 2,4-D 2,4-dichloroanisole ■ □ □ ■ 0.69 trifluralin a,a,a-trifluoro-5-nitro-4-propyl-toluene-3,4-diamine ■ □ □ ■ 0.61 chlorothalonil 3-cyano-6-hydroxy-2,4,5-trichlorobenzamide ■ □ □ ■ 0.60

96 chlorothalonil 3-carbamyl-2,4,5-trichlorobenzoic acid ■ ■ □ ■ 0.60 glyphosate AMPA ■ ■ ■ ■ 0.52 trifluralin [2,6-dinitro-4-(trifluoromethyl)phenyl]propylamine ■ □ □ ■ 0.50 trifluralin 2-ethyl-7-nitro-1-propyl-5-(trifluoromethyl) benzimidazole ■ □ □ ■ 0.29 chlorothalonil 3-cyano-2,5,6-trichlorobenzamide ■ □ □ ■ 0.22 2,4-D 2,4-dichlorophenol ■ ■ □ ■ 0.20 chlorpyrifos 3,5,6-trichloro-2-methoxypyridine ■ □ ■ ■ 0.19 ethephon ethylene ■ □ □ ■ 0.17 pendimethalin 2,6-dinitro-3,4-xylidine ■ □ □ ■ 0.17 pendimethalin 4-[(1-ethylpropyl)amino]-2-methyl-3,5-dinitro benzyl alcohol ■ □ □ ■ 0.17 pendimethalin 4-[(1-ethylpropyl)amino]-3,5-dinitro-o-toluic acid ■ □ □ ■ 0.17 metolachlor CGA-41638 ■ □ □ ■ 0.16 trifluralin 2-ethyl-7-nitro-1-propyl-5-(trifluoromethyl) benzimidazole-3-oxide ■ □ □ ■ 0.09 malathion malaoxon ■ □ □ ■ 0.09 metolachlor CGA-13656 ■ □ □ ■ 0.08

atrazine deethylatrazine ■ ■ ■ ■ 0.07 trifluralin 2,6-dinitro-4-(trifluoromethylphenyl)amine ■ □ □ ■ 0.06

Pesticide Degradate Formation Kd DT50 ADI RI

chlorothalonil 4-hydroxy-2,5,6-trichloroisophthalonitrile ■ ■ ■ ■ <0.01 EPTC EPTC sulfoxide ■ □ ■ ■ <0.01 metam sodium methylisothiocyanate ■ □ ■ ■ <0.01 dichloropropene chloroallyl alcohol □ □ ■ ■ <0.01

APPENDIX 9. THE RISK INDEX AND DATA AVAILABILITY FOR DEGRADATES FROM THE UK MOST USED AGRICULTURAL PESTICIDES

Pesticide Degradate Formation Kd DT50 ADI RI

cyanazine cyanazine acid □ ■ □ ■ 26.56 cyanazine cynazine amide □ ■ □ ■ 24.11 ©2008 AwwaRF. ALLRIGHTS RESERVED isoproturon 1-methyl-3-(4-isopropyl phenyl)-urea ■ □ □ ■ 7.92 flufenacet FOE sulfonic acid ■ □ □ ■ 4.67 bitertanol/tebuconazole 1,2,4-triazole ■ □ □ ■ 4.51 flufenacet FOE oxalate ■ □ □ ■ 3.25 dicamba 3,6-dichlorosalicylic acid ■ ■ □ ■ 3.15

99 atrazine/simazine deisopropylatrazine ■ ■ □ ■ 2.12 flufenacet FOE methyl sulfone ■ □ □ ■ 2.03 flufenacet FOE thioglycolate sulfoxide ■ □ □ ■ 2.03 flufenacet thiadone ■ □ □ ■ 2.03 metaldehyde acetaldehyde ■ □ □ ■ 1.63 bitertanol bitertanol benzoic acid ■ □ □ ■ 1.59 atrazine DEHA ■ □ □ ■ 1.29 propachlor propachlor oxanilic acid ■ ■ □ ■ 1.26 atrazine/simazine DIHA ■ □ □ ■ 1.21 trifluralin α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine ■ □ □ ■ 1.10 isoproturon 3-[4-(2’-hydroxy-2’-propyl)-phenyl]-methyl urea ■ □ □ ■ 1.01 bitertanol 4-hydroxybiphenyl ■ □ □ ■ 1.00 linuron demethyl linuron ■ □ □ ■ 0.99 atrazine/simazine diaminochloroatrazine ■ ■ □ ■ 0.89 dimethoate O-desmethyl dimethoate ■ □ □ ■ 0.81

propachlor propachlor ethane sulfonic acid ■ ■ □ ■ 0.72

Pesticide Degradate Formation Kd DT50 ADI RI

trifluralin 2,2’-azoxybis (α,α,α-trifluoro-6-nitro-N-propyl-p-toluidine ■ □ □ ■ 0.72 2-chloroethylphosphonic acid ethylene ■ □ □ ■ 0.67 trifluralin α,α,α-trifluoro-2,6-dinitro-p-cresol ■ □ □ ■ 0.65 trifluralin 2-ethyl-7-nitro-5-(trifluoromethyl) benzimidazole ■ □ □ ■ 0.62 asulam ionic form of asulam ■ □ □ ■ 0.61 chlorothanonil 3-cyano-2,4,5,6-tetrachlorobenzamide ■ □ □ ■ 0.61 chlorothanonil 3-carbamyl-2,4,5-trichlorobenzoic acid ■ ■ □ ■ 0.60 metalaxyl CGA-62826 ■ □ □ ■ 0.57 ©2008 AwwaRF. ALLRIGHTS RESERVED chloridazon 5-amino-4-chloropyridazine-3(2H)-one ■ □ □ ■ 0.54 metalaxyl 2-N-(2,6-dimethylphenyl)-2-methoxyacetylamino propanoic acid ■ □ □ ■ 0.53 trifluralin α,α,α-trifluoro-5-nitro-4-propyl-toluene-3,4-diamine ■ □ □ ■ 0.50 mecoprop-P 4-chloro-2-methyl phenol ■ □ □ ■ 0.50 azoxystrobin azoxystrobin metabolite 2 □ ■ □ ■ 0.42

100 trifluralin [2,6-dinitro-4-(trifluoromethyl)phenyl]propylamine ■ □ □ ■ 0.41 dimethoate O,O-dimethylphosphorothioic acid ■ □ □ ■ 0.38 3-isopropyl-2,3-dioxo-5-oxocyclo-penteno-IH-2,1,3-thiadazin- bentazone □ □ □ ■ 0.32 4(3H)-one-6-carbonic acid propachlor propachlor sulfinylacetic acid ■ □ □ ■ 0.26 chlorothanonil 3-carbamyl-1,2,4,5-tetrachlorobezoic acid ■ □ □ ■ 0.25 trifluralin 2-ethyl-7-nitro-1-propyl-5-(trifluoromethyl) benzimidazole ■ □ □ ■ 0.24 pendimethalin 2,6-dinitro-3,4-xylidine ■ □ □ ■ 0.23 pendimethalin 4-[(1-ethylpropyl)amino]-2-methyl-3,5-dinitro benzyl alcohol ■ □ □ ■ 0.23 pendimethalin 4-[(1-ethylpropyl)amino]-3,5-dinitro-o-toluic acid ■ □ □ ■ 0.23 atrazine hydroxy atrazine ■ ■ ■ ■ 0.23 propachlor hydroxypropachlor ■ □ □ ■ 0.23 cyprodinil CGA 249287 ■ □ □ ■ 0.22 chlorothanonil 3-cyano-6-hydroxy-2,4,5-trichlorobenzamide ■ □ □ ■ 0.22 linuron norlinuron ■ □ □ ■ 0.19 chlorothanonil 3-cyano-2,5,6-trichlorobenzamide ■ □ □ ■ 0.19

asulam conjugated form of asulam ■ □ □ ■ 0.17

Pesticide Degradate Formation Kd DT50 ADI RI

bitertanol biteranol ketone ■ □ □ ■ 0.17 quinmerac BH518-2 ■ ■ ■ ■ 0.16 azoxystrobin azoxystrobin acid ■ □ □ ■ 0.14 metaldehyde paraldehyde ■ □ □ ■ 0.13 quinmerac BH518-5 ■ ■ ■ ■ 0.13 propachlor propachlor methyl sulfone ■ □ □ ■ 0.12 asulam sulphanilamide ■ □ □ ■ 0.10 isoproturon desmethyl isoproturon ■ ■ ■ ■ 0.09 ©2008 AwwaRF. ALLRIGHTS RESERVED 2,4-D 2,4-dichloroanisole ■ □ □ ■ 0.08 tebuconazole SN 320-1 ■ □ □ ■ 0.08 tebuconazole SN 3678-7/A ■ □ □ ■ 0.08 tebuconazole SN 3678-7/B ■ □ □ ■ 0.08 trifluralin 2-ethyl-7-nitro-1-propyl-5-(trifluoromethyl) benzimidazole-3-oxide ■ □ □ ■ 0.07

101 terbuthylazine deethylterbuthylazine ■ □ □ ■ 0.07 simazine hydroxysimazine ■ ■ ■ ■ 0.07 azoxystrobin azoxystrobin metabolite 10 ■ □ □ ■ 0.07 azoxystrobin azoxystrobin metabolite 20 ■ □ □ ■ 0.07 azoxystrobin azoxystrobin metabolite 3 ■ □ □ ■ 0.07 captan tetrahydrophthalimide acid ■ □ □ ■ 0.05 trifluralin 2,6-dinitro-4-(trifluoromethylphenyl)amine ■ □ □ ■ 0.05 glyphosate AMPA ■ ■ ■ ■ 0.05 propachlor norchloropropachlor ■ □ □ ■ 0.05 azoxystrobin azoxystrobin metabolite 30 ■ ■ □ ■ 0.05 quinmerac BH518-1 ■ □ □ ■ 0.03 quinmerac BH518-4 ■ □ □ ■ 0.03 azoxystrobin azoxystrobin metabolite 28 ■ ■ □ ■ 0.02 2,4-D 2,4-dichlorophenol ■ ■ □ ■ 0.02 kresoxim methyl kresoxim-methyl acid ■ ■ ■ ■ 0.02 chloridazon 5-amino-4-chloro-2-methyl-2-hydropyridazin-3-one ■ □ □ ■ 0.02

mepiquat N-methylpiperidine ■ □ □ ■ 0.01

Pesticide Degradate Formation Kd DT50 ADI RI

mepiquat piperidine ■ □ □ ■ 0.01 (3,5-dichlorophenyl)-N-(2,3-dihydroxy-1,1- propyzamide ■ □ □ ■ 0.01 dimethylpropyl)carboxamide (3,5-dichlorophenyl)-N-(3-hydroxy-1,1-dimethyl-2- propyzamide ■ □ □ ■ 0.01 oxopropyl)carboxamide (3,5-dichlorophenyl)-N-(3-hydroxy-1,1- propyzamide ■ □ □ ■ 0.01 dimethylpropyl)carboxamide [2-(3,5-dichlorophenyl)-4,4-dimethyl-1,3-oxazolin-5- propyzamide ■ □ □ ■ 0.01 ylidene]methan-1-ol ©2008 AwwaRF. ALLRIGHTS RESERVED propyzamide 2-[(3,5-dichlorophenyl)carbonylamino]-2-methylpropanoic acid ■ □ □ ■ 0.01 3-[(3,5-dichlorophenyl)carbonylamino]-3-methyl-2-oxobutanoic propyzamide ■ □ □ ■ 0.01 acid propyzamide 3-[(3,5-dichlorophenyl)carbonylamino]-3-methylbutanoic acid ■ □ □ ■ 0.01 kresoxim methyl 490M0 ■ □ □ ■ 0.01

102 fluroxypyr 4-amino-3,5-dichloro-6-fluoro-methoxypyridine ■ □ ■ ■ 0.01 atrazine deethylatrazine ■ ■ ■ ■ 0.01 kresoxim methyl 490M4 ■ □ □ ■ 0.01 chlorothanonil 4-hydroxy-2,5,6-trichloroisophthalonitrile ■ ■ ■ ■ <0.01 clodinafop-propargyl 5-chloro-3-fluoro-2-hydroxy-pyridine ■ □ ■ ■ <0.01 propyzamide 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-methyleneoxazoline ■ ■ ■ ■ <0.01 fluroxypyr 4-amino-3,5-dichloro-6-fluoro-2-pyridinol ■ □ ■ ■ <0.01 dimethoate omethoate ■ □ ■ ■ <0.01 captan 1,2,3,6-tetrahydrophthalimide ■ ■ ■ ■ <0.01 2,4-DB 2,4-D ■ ■ ■ ■ <0.01 propyzamide N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide ■ ■ ■ ■ <0.01 bentazone n-methylbentazone □ ■ ■ ■ <0.01 ioxynil di-iodo-4-hydroxybenzamide ■ ■ ■ ■ <0.01 bromoxynil 3,5-dibromo-4-hydroxy benzamide ■ ■ ■ ■ <0.01 ioxynil di-iodo-4-hydroxybenzoic acid ■ ■ ■ ■ <0.01 bromoxynil 3,5-dibromo-4-hydroxy benzoic acid ■ ■ ■ ■ <0.01

REFERENCES

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©2008 AwwaRF. ALL RIGHTS RESERVED PSD, (1991d), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on metsulfuron-methyl, No. 38, Pesticide Safety Directorate, York, UK. PSD, (1991e), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on diclofop-methyl, No. 46, Pesticide Safety Directorate, York, UK. PSD, (1992a), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fluoroglycofen-ethyl, No. 50, Pesticide Safety Directorate, York, UK. PSD, (1992b), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on esfenvalerate, No. 55, Pesticide Safety Directorate, York, UK. PSD, (1992c), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on atrazine (1), No. 51, Pesticide Safety Directorate, York, UK. PSD, (1993a), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on imazaquin, No. 66, Pesticide Safety Directorate, York, UK. PSD, (1993b), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fenpropidin, No. 67, Pesticide Safety Directorate, York, UK. PSD, (1993c), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on 2,4-dichlorophenoxy acetic acid and its salts and esters, No. 68, Pesticide Safety Directorate, York, UK. PSD, (1993d), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on atrazine (2), No. 71, Pesticide Safety Directorate, York, UK. PSD, (1993e), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on imidacloprid, No. 73, Pesticide Safety Directorate, York, UK. PSD, (1993f), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on desmedipham, No. 75, Pesticide Safety Directorate, York, UK. PSD, (1993g), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fenpiclonil, No. 78, Pesticide Safety Directorate, York, UK. PSD, (1993h), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on dimefuron, No. 79, Pesticide Safety Directorate, York, UK. PSD, (1993i), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on buprofezin, No. 81, Pesticide Safety Directorate, York, UK. PSD, (1993j), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on dimethoate, No. 86, Pesticide Safety Directorate, York, UK. PSD, (1993k), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on chloropropham, No. 87, Pesticide Safety Directorate, York, UK. PSD, (1993l), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on cyromazine, No. 89, Pesticide Safety Directorate, York, UK. PSD, (1993m), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on kathon 886 use in wood preservation, No. 90, Pesticide Safety Directorate, York, UK. PSD, (1994a), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on amidosulfuron, No. 91, Pesticide Safety Directorate, York, UK. PSD, (1994b), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on bitertanol, No. 92, Pesticide Safety Directorate, York, UK. PSD, (1994c), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on anilazine, No. 93, Pesticide Safety Directorate, York, UK. PSD, (1994d), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on mecoprop, No. 95, Pesticide Safety Directorate, York, UK.

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©2008 AwwaRF. ALL RIGHTS RESERVED PSD, (1994e), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on mecoprop-p, No. 96, Pesticide Safety Directorate, York, UK. PSD, (1994f), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on triazoxide, No. 97, Pesticide Safety Directorate, York, UK. PSD, (1994g), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on dimethomorph, No. 99, Pesticide Safety Directorate, York, UK. PSD, (1994h), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fluazinam, No. 100, Pesticide Safety Directorate, York, UK. PSD, (1994i), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on hydramethylon use in public hygiene, No. 102, Pesticide Safety Directorate, York, UK. PSD, (1994j), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on difenoconazole in Plover 250 EC, No. 106, Pesticide Safety Directorate, York, UK. PSD, (1994k), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on chlorfenvinphos, No. 107, Pesticide Safety Directorate, York, UK. PSD, (1994l), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on epoxiconazole, No. 108, Pesticide Safety Directorate, York, UK. PSD, (1994m), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on alidcarb, No. 109, Pesticide Safety Directorate, York, UK. PSD, (1994n), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on IPBC (2), No. 115, Pesticide Safety Directorate, York, UK. PSD, (1995a), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fomesafen, No. 118, Pesticide Safety Directorate, York, UK. PSD, (1995b), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fludioxonil, No. 126, Pesticide Safety Directorate, York, UK. PSD, (1995c), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fenbucaonazole, No. 128, Pesticide Safety Directorate, York, UK. PSD, (1995d), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on fenpyroximate, No. 130, Pesticide Safety Directorate, York, UK. PSD, (1995e), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on diclofop-methyl (2), No. 117, Pesticide Safety Directorate, York, UK. PSD, (1998a), Advisory Committee on Pesticides Published Evaluation Documents, Evaluation on benfuracarb, No. 5, Pesticide Safety Directorate, York, UK. Punch, B., Patton, A., Wight, L., Larson, B., Masscheleyn, P., Forney, L. (1996) A biodegradability evaluation and simulation system (BESS) based on knowledge of biodegradation pathways. In Peijneburg, W.J.G.M., Damborsky, J. (Eds) Biodegradability prediction. Kluwer Academic Publishers, The Netherlands Punch, W.F., Forney, L.J., Patton, A., Wight, K., Masscheleyn, P. and Larson, R.J., (1997) BESS, a computerised system for predicting biodegradation potential of new and existing chemicals, In Chen, F. and Schüürmann, G. (Eds.) Quantitative Structure-Activity Relationships in Environmental Sciences - VII, SETAC, Florida, USA, pp 81- 92. Raju, G.S., Millette, J.A. and Khan, S.U. (1993), Pollution potential of selected pesticides in soils, Chemosphere, Vol. 26, No. 8, pp. 1429-1442. Ramwell, C.T., Heather, A.I.J. and Shepherd, A.J. (2002), Herbicide loss follwoing application to a roadside, Pest Management Science, Vol. 58, pp. 695-701.

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A Degradate amount index a.i. Active ingredient ADI Acceptable daily amount AE alcohol ethoxylates AME alkyl amine ethoxylates APE alkyl phenol ethoxylates AWWA American Water Works Association CO2 Carbon dioxide DEA deethylatrazine DIA deisopropylatrazine, DT50 Degradation half life for the degradate DWI Drinking Water Inspectorate E Exposure index ESA ethane sulfonic acids EU European Union F Fraction of degradate in the aqeous phase GC-MS Liquid chromatography mass spectrometry GWRC Global Water Research Coalition HA hydroxyatrazine HPLC High performance liquid chromatography Kd sorption coefficient Koc Organic carbon sorption coefficient LAS linear alkylbenzene sulfonates LC-MS Liquid chromatography mass spectrometry LCS liquid scintillation counting MCL Maximum concentration limit NMR Nuclear magnetic resonance OA oxanilic acids OECD Organisation for Economic Co-operation abd Development OP organophosphorus insecticides P Persistence index QSAR Quantitative structure-activity relationships RI Degradate risk index SBR Structure-biodegradability relationships SSLRC Soil Survey and Land Research Centre t Tonne t½ Half-life UK United Kingdom US United States USEPA United States Environmental Protection Agency USGS United States Geological Survey UV Ultraviolet WWTPs Wastewater treatment plants

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