Normes OEPP EPPO Standards

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1 2003 OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 33, OEPP/EPPO, Blackwell Oxford, EPPO Environmental Bulletin Original Standards UK OEPP/EPPO Article Publishing 2003 risk asessment Ltd. Bulletin for plant protection products Organisation Européenne et Méditerranéenne pour la Protection des Plantes European and Mediterranean Plant Protection Organization Normes OEPP EPPO Standards Environmental risk assessment scheme for plant protection products Système pour l évaluation du risque des produits phytosanitaires pour l environnement PP 3/6 (revised) PP 3/13 Organisation Européenne et Méditerranéenne pour la Protection des Plantes 1, rue Le Nôtre, Paris, France 147

2 148 Environmental risk assessment of plant protection products Approval EPPO Standards are approved by EPPO Council. The date of approval appears in each individual standard. Review EPPO Standards are subject to periodic review and amendment. The next review date for this set of EPPO Standards is decided by the EPPO Working Party on Plant Protection Products Amendment record Amendments will be issued as necessary, numbered and dated. The dates of amendment appear in each individual standard (as appropriate). Distribution The EPPO Standards making up the EPPO/Council of Europe decision-making scheme for the environmental risk assessment of plant protection products are distributed by the EPPO Secretariat to all EPPO member governments. Copies are available to any interested person under particular conditions upon request to the EPPO Secretariat. Scope The EPPO Standards making up the EPPO/Council of Europe decision-making scheme for the environmental risk assessment of plant protection products are intended to be used by National Plant Protection Organizations or equivalent national authorities, in their capacity as bodies responsible for the registration of plant protection products, including an evaluation of the environmental risks arising from their use. Outline of requirements The decision-making scheme for the environmental risk assessment of plant protection products was developed by a joint Panel of EPPO and the Council of Europe and provides guidelines on how to assess the potential impact of a particular plant protection product on various different elements of the environment, each element being presented as a separate standard. The assessment scheme is for use by agrochemical companies and by regulatory authorities, and aims to: 1 guide assessors on the questions that should be addressed, and the data that may need to be requested from registrants; 2 provide information on the test methods and approaches that are suitable in each case; 3 indicate how the data should be interpreted in a consistent manner, involving expert judgement where appropriate; 4 produce a reliable assessment of environmental risk, as a suitable aid to risk management (though the assessment scheme will not provide all the information needed for decisions on the acceptability of plant protection products). The Standards in the scheme provide a set of flexible procedures that can be adapted for use in various ways according to the priorities in different countries, yet retain the consistency of a common framework. They are not based on a series of fixed, automatic triggers for testing requirements, but are able to take full account of the particular features of each plant protection product, and to make use of expert judgement when necessary. Approbation Les Normes OEPP sont approuvées par le Conseil de l OEPP. La date d approbation figure dans chaque norme individuelle. Révision Les Normes OEPP sont sujettes à des révisions et des amendements périodiques. La prochaine date de révision de cette série de Normes OEPP est décidée par le Groupe de travail sur les produits phytosanitaires. Enregistrement des amendements Des amendements sont préparés si nécessaires, numérotés et datés. Les dates de révision figurent (si nécessaire) dans chaque norme individuelle. Distribution Les Normes OEPP composant le système de décision OEPP/Conseil de l Europe pour l évaluation du risque des produits phytosanitaires pour l environnement sont distribuées par le Secrétariat de l OEPP à tous les Etats membres de l OEPP. Des copies sont disponibles, sous certaines conditions, auprès du Secrétariat de l OEPP pour toute personne intéressée. Champ d application Les Normes de l OEPP composant le système de décision OEPP/Conseil de l Europe pour l évaluation du risque des produits phytosanitaires pour l environnement sont destinées aux Organisations Nationales de Protection des Végétaux, en leur qualité d autorités responsables de l homologation des produits phytosanitaires, qui comporte une évaluation des risques pour l environnement liés à l utilisation de ces produits, et aux firmes agrochimiques demandant l homologation de leurs produits. Vue d ensemble Le système de décision pour l évaluation du risque des produits phytosanitaires pour l environnement a été mis au point par un Groupe d experts conjoint OEPP et Conseil de l Europe. Il donne des recommandations sur la manière d évaluer l impact potentiel d un produit phytosanitaire donné sur diverses composantes de l environnement, chacun de ces composantes étant traitée dans une norme distincte. Le système d évaluation a pour objectif de: 1 guider les responsables des évaluations sur les questions à aborder et sur les données que les demandeurs de l homologation peuvent avoir à fournir; 2 donner des informations sur les méthodes d essai et les approches appropriées dans chaque cas; 3 montrer comment interpréter les données d une manière cohérente, en ayant recours au jugement d experts lorsque cela s impose; 4 permettre une évaluation fiable du risque pour l environnement, pouvant faciliter la gestion du risque (même si le système d évaluation ne fournira cependant pas toutes les informations nécessaires pour décider de l acceptabilité des produits phytosanitaires). Les Normes OEPP qui composent le système présentent une série de procédures souples qui peuvent être adaptées et utilisées de différentes manières dans différents pays, tout en conservant la cohérence d un cadre commun. Elles ne reposent pas sur une série de seuils fixes définissant automatiquement la nécessité de conduire des essais, mais permettent de tenir compte de l ensemble des caractéristiques particulières de chaque produit phytosanitaire et de recourir au jugement d experts lorsque cela s impose OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 33,

3 EPPO Standards 149 Existing EPPO Standards in this series The first 10 Standards in the scheme were originally published in Bulletin OEPP/EPPO Bulletin in 1993/1994: OEPP/EPPO (1993) Decision-making scheme for the environmental risk assessment of plant protection products. Chapters 1 6, 8 & 10. Bulletin OEPP/EPPO Bulletin 23, OEPP/EPPO (1994) Decision-making scheme for the environmental risk assessment of plant protection products. Chapters 7, 9 & 11. Bulletin OEPP/EPPO Bulletin 24, Over the period from 1994 to 2002, these texts were first reformatted as EPPO Standards, to constitute Series PP 3. All the Standards were then updated to take account of new developments and two additional Standards were approved. Chapters 7 and 8 were combined. A first set of these new and revised standards was published as follows: PP 3/1 (2) Chapter 1: Introduction. Bulletin OEPP/EPPO Bulletin 33, PP 3/2 (2) Chapter 2: Guidance on identifying aspects of environmental concern. Bulletin OEPP/EPPO Bulletin 33, PP 3/9 (2) Chapter 9: Non-target terrestrial arthropods. Bulletin OEPP/ EPPO Bulletin 33, PP 3/10 (2) Chapter 10: Honeybees. Bulletin OEPP/EPPO Bulletin 33, PP 3/12 (1) Chapter 3: Air. Bulletin OEPP/EPPO Bulletin 33, The present set completes the Series. Although the original set of Standards was published bilingually in English and French, the present set is now published only in English. The new French versions of these Standards will be published at a later date. The corresponding old English and French versions of the Standards in this set are withdrawn. Normes OEPP déjà existantes dans cette série Les 10 premières Normes de ce système ont initialement été publiées dans le Bulletin OEPP/EPPO Bulletin en 1993/1994: OEPP/EPPO (1993) Système pour l évaluation des effets non intentionnels des produits phytosanitaires sur l environnement. Chapitres 1 6, 8 & 10. Bulletin OEPP/EPPO Bulletin 23, OEPP/EPPO (1994) Système pour l évaluation des effets non intentionnels des produits phytosanitaires sur l environnement. Chapitres 7, 9 & 11. Bulletin OEPP/EPPO Bulletin 24, Entre 1994 et 2002, ces textes ont d abord été reformatés sous forme de Normes OEPP, pour former la série PP 3. Ces Normes ont ensuite été mises à jour pour tenir compte des évolutions dans ce domaine et deux Normes supplémentaires ont été approuvées. Les chapitres 7 et 8 ont été combinés. Un premier groupe de ces Normes nouvelles et révisées a été publié comme suit: PP 3/1 (2) Chapter 1: Introduction. Bulletin OEPP/EPPO Bulletin 33, PP 3/2 (2) Chapter 2: Guidance on identifying aspects of environmental concern. Bulletin OEPP/EPPO Bulletin 33, PP 3/9 (2) Chapter 9: Non-target terrestrial arthropods. Bulletin OEPP/ EPPO Bulletin 33, PP 3/10 (2) Chapter 10: Honeybees. Bulletin OEPP/EPPO Bulletin 33, PP 3/12 (1) Chapter 3: Air. Bulletin OEPP/EPPO Bulletin 33, Les Normes publiées ici complètent la série. Bien que la série originale de Normes ait été publiée sous forme bilingue, en anglais et en français, la présente série n est publiée qu en anglais. Les nouvelles versions françaises de ces Normes seront publiées ultérieurement. Les anciennes versions, anglaises et françaises, des Normes de cette série sont retirées OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 33,

4 Blackwell Publishing Ltd. European and Mediterranean Plant Protection Organization PP 3/6(2) Organisation Européenne et Méditerranéenne pour la Protection des Plantes Environmental risk assessment scheme for plant protection products Chapter 7: Aquatic organisms Specific scope This standard provides an assessment of risk presented by plant protection products to aquatic organisms. Specific approval and amendment First approved in Edited as an EPPO Standard in Revision approved in Introduction This subscheme for aquatic organisms was originally based on the recommendations of an OECD Workshop on Ecological Effects Assessment held in 1988 in Washington (US) (OECD, 1989). It was updated in The subscheme has three aims: 1 to identify plant protection products whose use could lead to short- or long-term declines in the viability of aquatic wildlife populations and communities; 2 to identify plant protection products which may bioaccumulate in fish and shellfish and from there, possibly result in significant exposure to man and other predators; 3 to identify those plant protection products which may cause kills of fish, large invertebrates, or terrestrial predators of fish, irrespective of whether such kills have effects at the population or community level. This is because even small ecologically irrelevant wildlife kills are now considered to be unacceptable by most members of the public. The subscheme follows a sequential or tiered approach, and is based on the comparison of predicted harmful concentrations with predicted environmental concentrations (PEC). Progression from one tier to the next is generally determined by the failure to exceed empirically derived uncertainty factors, although expert judgement plays an important part. This approach was endorsed by the OECD Workshop on Extrapolation of Aquatic Toxicity Data to the Real Environment (December 1990, Washington, US), and is the only reliable method which can be used for the small data sets associated with new notifications of plant protection products. It is based on long experience with both plant protection products and industrial chemicals. New probabilistic approaches to risk assessment are being developed, but these are data-intensive and are not generally ready for routine application in the environmental risk assessment of plant protection products. The subscheme contains many decision points where expert judgement is specifically requested. This is important because, if the subscheme is to be useful throughout the EPPO region, it should incorporate sufficient flexibility to take account of regional differences in farming practice, climate, etc. The subscheme cannot therefore be operated without the experience of an ecotoxicologist. It is primarily designed to ensure consistency of overall approach between different regulatory authorities. The subscheme also has decision points based on critical values of certain parameters. Suggested critical values are shown in square brackets, but expert judgement may be needed to decide on suitable values for any given region. In order to facilitate understanding of the subscheme, it has been summarized in a flow chart (Fig. 1). The chart should not be used as a substitute for working through the subscheme itself, but it does indicate which sections of the subscheme are needed in particular circumstances. The subscheme was reviewed and updated by an expert working group in 2000/2001. One or two loopholes in the original subscheme have been closed off, all aspects concerning prediction of environmental concentrations have been eliminated (they are fully covered in the revision of Chapter 6 Surface water and sediment), the scheme has been simplified, more detail has been given on higher-tier risk assessments, and assessment of sediment toxicity has been fully incorporated. However, the essential details of the approach remain the same and it is not anticipated that the outcome of risk assessments performed with the new subscheme will differ greatly from those produced by the original procedure. The revision has been influenced by experience with the EU Directive 91/414 risk assessment of plant protection products, but users of the present subscheme are still free to use assessment factors and other numerical values which best suit their local circumstances. The guiding principle in the revision has been to follow current best practice rather than to recommend new procedures which are still in the development phase, and it is worth reiterating that the subscheme cannot be operated without inputs from suitable experts. Risk assessment scheme Details of the product and its pattern of use 1 Take from Chapter 2 the basic information on the product and its pattern of use. go to 2 183

5 184 Aquatic organisms Fig. 1 Simplified diagram of the subscheme for evaluation of the risk of a plant protection product for aquatic organisms.

6 Environmental risk assessment scheme for plant protection products 185 Possibility of exposure 2 Is exposure of aquatic organisms possible (see Note 1)? If no Categorize as Negligible Risk If yes go to 3 Properties of the active substance(s) and relevant major metabolites (see Note 4) The information requested here should be obtained from data already available (e.g. published literature or nonpublished reports for registration application), or from the output of other Chapters within the scheme, concerned with distribution of active substances in the environment. 3 Obtain the following information (see Note 2): solubility in water octanol/water partition coefficient vapour pressure soil organic carbon adsorption coefficient photodegradation rate In addition, obtain the following information: aquatic hydrolysis data (half-life at ph 5, 7 and 9 and 20 C) sediment-water fate data go to 4 4 Obtain information on the toxicity of the active substance to representative species of aquatic organisms, including data from the human health assessment. The test results should generally cover (see Notes 3 and 8) h LC(EC)50 data on the active substance for a minimum of 1 alga, 1 crustacean and 1 fish. If the active substance persists in water, it will also be necessary to obtain chronic or subchronic toxicity data (as noobserved-effect-concentrations or NOECs) for the most acutely sensitive group of organisms. Note that toxicity data on growth of a macrophyte such as Lemna is also desirable for herbicides (see Note 3). Also enter aquatic toxicity data on the formulated product, and metabolites where relevant (see Note 4). go to 5 5 From Chapter 6 (Surface water and sediment), obtain the initial and time-weighted average short-term PECs and the long-term PEC in water (see Note 5) go to 6 6 From Chapter 6 (Surface water and sediment), obtain shortterm and/or long-term measured environmental concentrations (MECs) in water go to 7 Acute effects The purpose of these steps is to identify the degree of shortterm risk to be expected on the basis of the initial dataset by comparing short-term PECs with acute toxicity. This will give Exposure-Toxicity Ratios (ETR). If expected risk is high (high ETR), one is asked to consider whether higher-tier data is required to lessen the degree of uncertainty. If expected risk is lower (lower ETR), the assessor should predict whether long-term exposure and hence chronic toxicity and bioaccumulation are likely. In both cases, the MEC values which may be derived from post-registration field monitoring of pesticide concentrations can also be used in the present scheme in place of PECs to produce refined estimates of risk to aquatic organisms. 7 Calculate the exposure/toxicity ratio or ETR (initial shortterm PEC/acute LC(EC)50) for the most sensitive species tested and for the acute PEC (including the integrated PEC). This applies to both the active substance and to formulants judged to be toxic. It may be appropriate to use the timeweighted average PEC if the active substance dissipates rapidly in the environment (e.g. a few hours), particularly if the mode of action is time-dependent and/or reversible. Consult an expert in order to decide whether toxicity data on the active substance. or the formulation is the more appropriate for each scenario. Now take the largest ETR derived from the base-set data and proceed as follows: If largest ETR a [a = 0.01, but see Note 3 concerning algae] go to 12 If largest ETR > a go to 8 Importation of information on environmental concentrations Chapter 6 (Surface Water and Sediment) provides calculations of short- and long-term concentrations in water which are expected to result from the various translocation and dissipation processes. The short-term predicted environmental concentration (PEC) (e.g. based on expected drift, atmospheric decomposition, drainage and run-off, and calculated either as an initial concentration, a peak concentration due to multiple applications, or as a short-term time-weighted average) and the long-term PEC (based on relevant emission routes and calculated as a time-weighted average) can therefore be imported to the present subscheme. Predictions of risk to aquatic organisms at the conclusion of this subscheme may also trigger the conduct of field monitoring (for products already on the market) which can generate measured environmental concentrations (MEC). Further guidance on calculating PECs for specific scenarios (e.g. PECs in bulk sediment) is available from FOCUS (2001). Higher-tier studies These are optional studies which can be used to lessen the degree of uncertainty surrounding predictions of high risk made on the basis of lower-tier data. They range from further singlespecies tests, through modified exposure studies (e.g. influence of sediment), to multispecies tests (which can include indoor or outdoor micro/mesocosm tests). They can also include measurements of persistence and bioaccumulation as well as of toxic effects (see Note 6). 8 Consult an expert in order to decide whether to obtain additional acute toxicity data with a broader range of species (5-8) which will permit the use of smaller uncertainty factors (or, potentially, probabilistic risk assessments), or whether modified acute-exposure studies with standard species (to investigate whether exposure to water dwellers is reduced due to adsorption) should be performed. These studies may, as appropriate, concern Acute Risk (coming from 7 or 15), or Chronic Risk (coming from 19 or 21). Is it desirable to conduct short- or

7 186 Aquatic organisms long-term, laboratory or field, multispecies tests (Note 6) in order to reduce uncertainty? If no Categorize as High Acute Risk or High Chronic Risk, as appropriate go to 24 If yes go to 9 9 Apply the product in multispecies test(s) at concentrations including the short-term or long-term PEC/MEC (as appropriate), and answer some or all of the following questions: (a) Do any species of fish or large invertebrate suffer direct mortality at concentrations PEC? (b) Is the Ecologically Acceptable Concentration (see Note 6) PEC? (c) Do residues of the active substance bioaccumulate in any species? If answer (a) is positive Categorize as High Acute Risk If answer (b) is positive Categorize as High Chronic Risk If answers (a) and (c) are negative Categorize as Low Acute Risk If answers (b) and (c) are negative Categorize as Low Chronic Risk go to If answer (c) is positive, refer the bioaccumulation data to Chapter 11 (Terrestrial vertebrates) go to If both acute and chronic risk have been categorized go to 24 If only acute risk has been categorized go to 17 Otherwise go to 12 Sediment toxicity Some substances can partition to, and persist in, sediments and may therefore cause toxicity to sediment-dwelling organisms. This section identifies substances which can potentially cause sediment toxicity, and subjects them to a sediment toxicity test (see Note 7). 12 In a sediment/water fate test, is > b% [b = 10] of the applied radioactivity (due to the parent compound) present in the sediment phase after c days [c = 14]? If yes go to 13 If no go to In a chronic Daphnia toxicity study, is the NOEC < d mg L 1 [d = 0.1]? If yes go to 14 If no go to Conduct a sediment toxicity test with at least one species of invertebrate, and calculate the largest sediment ETR go to 15 Calculation of acute exposure/toxicity ratios Risk is now categorized on the basis of acute toxicity data, but the subscheme subsequently requires an assessment of possible long-term risks. Although an enlarged acute toxicity dataset may permit the application of probabilistic risk assessment (see Note 6), there is still insufficient experience with this approach for it to be confidently recommended. However, such a dataset does generally permit an order-of-magnitude reduction in uncertainty factors. Note also that if a higher-tier modified exposure test shifts the largest ETR into a lower range (e.g. from 0.01 to 0.1 to < 0.01), then the Acute Risk Category can be reduced accordingly, or a more realistic higher-tier test (e.g. a short-term outdoor mesocosm study) can be triggered (go back to 8) to confirm the prediction of reduced exposure. Equally, predictions of high acute risk may trigger short-term multispecies studies (go back to 8) in order to reduce uncertainty. 15 If largest acute ETR is low [< 0.01 for three aquatic toxicity tests or < 0.1 for eight aquatic tests or < 0.1 for sediment toxicity test], categorize as Low Acute Risk. If largest acute ETR is medium [ for three aquatic toxicity tests or for eight aquatic tests or for sediment toxicity test], categorize as Medium Acute Risk. If largest acute ETR is high [> 0.1 for 3 aquatic toxicity tests or > 1 for 8 aquatic tests or > 1 for sediment toxicity test], categorize as High Acute Risk. go to 16 Persistence and bioaccumulation potential These steps are designed to establish whether chronic exposure or bioaccumulation are likely. If they are, the subscheme requests chronic toxicity and/or bioconcentration data. If they are not, the subscheme proceeds to categorization. 16 If chronic risk has already been categorized in highertier tests go to 24 Otherwise go to Is half-life in sediment-water fate study (either phase) > e days [e = 2], or is chronic exposure expected due to repeated applications? If yes to either question go to 18 If no to both questions Categorize as Medium Chronic Risk go to Is log K ow > f [f = 3] If yes go to 19 If no go to 21 Chronic effects and bioconcentration These steps call for bioconcentration and chronic toxicity tests to be conducted. The assessor is then asked to calculate chronic ETRs (see Note 8). Extra chronic tests may be requested in order to reduce the uncertainty of predictions. Although an enlarged chronic toxicity dataset may permit the application of probabilistic risk assessment (see Note 6), there is still insufficient experience with this approach for it to be confidently recommended. However, such an enlarged dataset does generally permit a reduction in uncertainty factors. After this section, the subscheme proceeds to categorization, unless the assessor decides on the need for higher tier testing (go back to 8). 19 Conduct a bioconcentration test (see Note 9) with at least one suitable species (including a fish) and record the steady-state bioconcentration factor (BCF). If largest BCF < g [g = ] go to 21 If any BCF > g go to 20

8 Environmental risk assessment scheme for plant protection products Refer the BCF data to Chapter 11 (Terrestrial vertebrates) go to Conduct a chronic toxicity test(s) (including tests with major degradation products if these are stable) with the most acutely sensitive species of Daphnia or fish, as appropriate (see Note 8). Calculate the chronic ETR (long-term PEC/chronic NOEC). It is permissible to use the short-term algal toxicity values if they are lower than the Daphnia or fish chronic data. It may be appropriate to use the time-weighted average PEC if the active substance dissipates rapidly in the environment (e.g. over a few days), particularly if the mode of action is time-dependent and/or reversible. If largest chronic ETR h [h = 0.1], categorize as Low Chronic Risk If largest chronic ETR h, but any available BCF > g, categorize as High Chronic Risk If largest chronic ETR > h go to 22 Note that if a higher-tier modified exposure test shifts the chronic ETR into a lower range (e.g. from > 0.1 to < 0.1), then the Chronic Risk Category could be reduced accordingly, or a more realistic higher-tier test (e.g. a long-term outdoor mesocosm study) could be triggered (go back to 8). 22 Consult an expert in order to decide whether chronic tests with additional taxa or population-level studies in the laboratory are required to lessen the uncertainty of extrapolation to the real environment (see Note 6). If yes Go to 23 If no Categorize as High Chronic Risk 23 Conduct additional chronic tests with 5-8 appropriate taxa. Choice of test species will depend in part on the available acute toxicity data. Is largest chronic ETR > i [i = 0.2]? If yes Go back to 8 If no, and any available BCF < g, categorize as Medium Chronic Risk If no, and any available BCF > g, categorize as High Chronic Risk Categories of risk The preceding sections allowed the use of the product to be allocated to one of seven categories of risk for aquatic organisms: negligible risk (see Note 11); low, medium or high acute risk; low, medium or high chronic risk (see Note 10). 24 If either acute or chronic risk is categorized as high (see Note 14 and 15) go to 27 Otherwise (see Notes 12, 13 and 15) go to 25 Analysis of uncertainty After completing the risk assessment based on data reflecting normal use of the product, it is necessary to consider whether errors in measurements, or variations in conditions of use, may alter the conclusions. This is appropriate for products initially categorized as a medium or low risk to aquatic organisms, to detect cases in which risks might be higher in practice. 25 Repeat the assessment, using values that represent realistic extremes of variation in the direction of higher risk, for certain critical parameters (see Note 14). Is the risk category changed by the repeat assessment? If yes go to 26 If no, confirm initial assessment go to Consider whether the lower risk category identified by preliminary assessment, or the higher category in the repeat assessment, is more appropriate as a basis for classification and approval of the product s use. go to Review the data which led to the high-risk category and check whether the conclusions are correct. If yes, confirm assessment go to 28 If no, obtain more information as needed go to 4 28 The assessor should consider whether field studies of environmental fate or, in the case of products already on the market), postregistration monitoring are required to provide data on exposures experienced by organisms in the field (Note 15). If field exposure data is required go to 6 If field exposure data is not obtained, or has already been used to revise risk categories go to 29 Risk management 29 The following risk management measures are to be considered as merely illustrative of the type of approach which can be taken. Individual regulatory jurisdictions will, of course, be the final arbiters of how risks are to be controlled. No particular aquatic risk management procedures will be necessary for a product identified as having negligible risk. Any product may, however, have high direct toxicity to aquatic organisms and should be labelled with an aquatic toxicity classification. All products in the low-risk category will be safe for the aquatic environment when used at the recommended application rate, including aerial and bankside applications. The majority will also be safe for use in water. Although all these products are in the low-risk category, some may have high toxicity to aquatic life under laboratory conditions and should be labelled accordingly. The potential exposure of potable water supplies posed by those which persist in water should be carefully considered (see Chapters 5 and 6). All products in the medium-risk category could cause damage to aquatic organisms when used at the recommended application rate under certain circumstances. They should not be applied from the air or on bankside vegetation, and should not be used in water. Improved engineering controls on sprayers may be considered to reduce spray drift. Also, the use of medium-risk products may have to be restricted to soils which are not subject to excessive crack-flow or surface run-off, and it may be necessary to prohibit use on certain leaching-prone soils and aquifers. All products in the high-risk category are likely to harm aquatic organisms unless their conditions of use are adequately controlled. As well as applying the restrictions outlined above

9 188 Aquatic organisms for medium-risk products, the use of unsprayed buffer zones between treated fields and adjacent surface water should be considered, as well as the use of stringent engineering controls on sprayers to prevent spray drift. The size of these buffer zones should be determined by formulation characteristics, mode of application and local circumstances. Explanatory notes Note 1. Possibility of exposure If the product is used exclusively indoors (including glasshouses) and cannot reach surface water by an indirect route (e.g. vegetable washings), then assume that aquatic organisms will not be exposed. Note 2. Test methods for properties of active substance The American (USEPA, 1998), Canadian, German (BBA, 1990), Dutch and British (MAFF, 1992) registration authorities have inter alia produced national guidelines for fate (degradation and partitioning) in natural sediment-water systems, and a draft OECD guideline has recently been developed (OECD, 2000a). These take natural sediment and water from clean field sites and hold them in static columns in the laboratory to which are introduced radio-labelled plant protection products for the degradation and partitioning study. Labelled CO 2 and volatiles are trapped, and radioactive label in water and sediment is measured at intervals. This type of study is now considered to provide essential data for all aquatic risk assessments of plant protection products. Note 3. Acute toxicity test methods Although these methods do not require analytical verification of test concentrations, it is current best practice to supply such information, especially if the test material is expected to degrade rapidly, adsorb to surfaces, be absorbed rapidly by test organisms, or volatilize. Toxicity to unicellular algae: OECD Test Guideline no (OECD, 1984a). Acute toxicity to aquatic macrophytes (Lemna spp.): EPA (1985) (not internationally accepted); ASTM (1997a,b); OECD (2000e) 2. Acute toxicity to fish: OECD Test Guideline no. 203 (OECD, 1992a). Acute toxicity to Daphnia magna: OECD Test guideline no. 202 (OECD, 1984b). 1This last test includes several generations of algae, and can therefore also be considered to provide chronic toxicity data to which a smaller uncertainty factor may apply than for acute data. 2Lemna toxicity data is required for all herbicides in the EU, and for all herbicides and fungicides in the USA. However, Lemna is not a perfect surrogate for all aquatic macrophytes as some substances are more toxic to the latter. Acute toxicity to other invertebrates: ASTM (1989) (not internationally accepted). Note 4. Toxicity of metabolites and formulations Metabolites Toxicity tests with an individual metabolite should generally be required where it is measured in water/sediment fate studies in the water phase in an amount which constitutes > x% (value of x = 10 suggested) of the applied radioactivity (AR). However, where there are indications that other metabolites give rise to a particular concern, their toxicity should also be addressed with a specific justification or a special risk assessment. Water/ sediment fate tests are carried out in the dark, and do not take into consideration possible photolysis of a substance and should as such not be used as the only study relevant for determining major metabolites which may require testing. The whole spectrum of environmental fate studies should be used to determine whether the x% trigger is reached. Tests may not be required for metabolites which are generated relatively rapidly by hydrolysis, as their toxicity may be exerted in the tests (particularly static tests) with the parent compound. This conclusion should be supported by analytical measurements on the metabolite in the toxicity test. If more than one metabolite is considered significant, it may not be necessary to require the same package of tests as for the parent compound on all of them. Alternatively, an appropriately designed microcosm or mesocosm study to address the risk from the parent compound and metabolites could be undertaken. In general, the same set of toxicity studies should be submitted as for an active substance. However, if acute toxicity tests with the active substance show that one taxonomic group is clearly the most sensitive, by a factor of y (y = 100 is suggested) to the next most sensitive one, testing on a metabolite can be restricted to that group. If the metabolite is more toxic to one taxonomic group than the parent compound, testing should be performed on all groups. Initially, it is only necessary to test the most sensitive species from a particular group; for example, a test on one appropriate fish species should be sufficient. Testing on additional species may then be necessary in some cases, where the risk to a particular group is considered to be of concern and is predicted to be greater than from exposure to the parent compound. In deciding whether chronic testing of metabolites is necessary, the intended uses, fate and behaviour of the metabolite, and the acute ETR values for the metabolite should be taken into account. In general, chronic/long-term tests are only necessary if the persistence trigger for chronic tests is surpassed for the metabolite. In terms of the choice of taxonomic group(s) to be studied, this should take account of any acute toxicity data on the metabolite, the acute and chronic toxicity data on the active substance, and data on fate and behaviour in aquatic systems. Only if the metabolite is more acutely toxic than the active substance should long-term/ chronic tests be required. Where acute toxicity data is available on fish and Daphnia for

10 Environmental risk assessment scheme for plant protection products 189 a particular metabolite, chronic testing should only be required on the most sensitive group. For unstable active substances (i.e. those that do not meet the persistence criteria), it may be more appropriate to conduct chronic studies on a stable metabolite instead of the parent compound. For unstable active substances, where chronic toxicity data for the parent compound is not available and an environmentally significant metabolite exceeds the persistence criteria, chronic toxicity data should be submitted for this metabolite regardless of its acute toxicity, for the most sensitive group as identified in acute toxicity studies on the metabolite. Where a metabolite is detected in the sediment phase of a sediment/water fate study and constitutes > x% AR, the criteria detailed in this document should be used to determine whether sediment toxicity data are required. However, when there are indications that other metabolites give rise to particular concern, these should also be addressed with a specific justification. Where a sediment toxicity study is carried out using the parent compound as the test material, this may address the risk from metabolites as well, if they are produced in the test system. However, when metabolites in such a system are the main concern, it should be borne in mind that chronic sediment toxicity may be the most relevant endpoint. Some active substances are metabolized in soil to mobile compounds which may not otherwise be produced by the degradation of the active substance in the aquatic environment. If fate and behaviour data suggest that, through drainage/ leaching, such a compound constitutes an environmentally significant residue in surface water, it may be necessary to require toxicity data for it. A metabolite that is more toxic than the active substance is included in the definition of environmentally significant residue, and should therefore contribute to the overall environmental risk assessment. Acute toxicity tests with the formulated product Acute toxicity studies should not be required on every formulation. However, co-formulants and solvents in formulations may significantly increase or decrease the acute toxicity of the active substance and there is some difficulty in predicting which types of formulations are critical in terms of such interactions. If the formulated product contains more than one active substance, this also complicates the prediction of toxicity using data on the individual active substances, to the extent that tests on such products are usually required. Acute toxicity data on a formulation also takes the toxicity of the co-formulants into account, as their toxicity will also be exerted in the tests. If the active substance is more acutely toxic when in formulation, ETRs should be calculated on the basis of the data for the product. If the formulated active substance is clearly less acutely toxic than the technical grade active substance, this fact should be taken into account, if relevant, within the refined risk assessment. Where available information on the active substance permits the conclusion that one group of organisms (algae, Daphnia, fish, etc.) is clearly more sensitive, tests on only the most sensitive species of the relevant group should be performed. In this context, the most sensitive group should be defined as z times (z = 100 is suggested) more sensitive than the next most sensitive. If the least sensitive group is z times less sensitive than the most sensitive, then formulation data need not be required on the least sensitive group. If the formulated product contains two or more active substances, and the most sensitive taxonomic groups for the individual active substances are not the same, formulation toxicity data should be required on all three groups. There is some scope for extrapolation of toxicity data between similar formulations. In addition, in some cases it may be possible reliably to predict the toxicity of a simple formulation from data on the active substance and information on the co-formulants. Such approaches should be justified in reasoned cases. Chronic toxicity tests with the formulated product It is unclear, on the basis of current knowledge, what criteria should be used to decide whether laboratory chronic toxicity data is necessary for a particular plant protection product. It can be argued that chronic formulation studies provide valuable information on sublethal effects from exposure to active substance/co formulant interactions. However, the fundamental question whether formulations persist in freshwater aquatic systems, as formulations, over longer time periods remains to be settled, and further discussion and input are required. At present, a refined chronic/prolonged exposure assessment cannot be carried out for a formulation, since water/sediment studies for products are not usually available. However, comparisons between the data from analytical measurements in the toxicity tests with the active substance and the formulated product may be helpful in deciding on this question. Without a refined exposure estimate, a NOEC from a chronic formulation study can only be compared with the initial formulation PEC, which may lead to an overestimation of risk. Even though some important areas are yet to be resolved, day-to-day decisions on the need for chronic data on specific formulations have to be made. The following guidance may be useful to address this issue. Long-term/chronic tests with the formulated product are not necessary if continued or repeated exposure is not possible. Therefore, chronic toxicity data are not required if it can be clearly demonstrated that the formulation will not persist in natural sediment/water systems and that continued or repeated exposure will not occur. However, long-term/chronic tests with the formulated product should be required for that group of organisms where the formulated active substance is more acutely toxic than the technical active substance by α orders of magnitude (α = 1 suggested) or greater. Relevant information especially concerning the effect of specific co-formulants on the fate and effects of the active substance could be required and used more routinely in the assessment. Further, the LC/EC50 in the acute test on fish or Daphnia with the formulated product should be < β mg formulation per L (β = 10 suggested).

11 190 Aquatic organisms In general, the same type of toxicity studies should be submitted as for an active substance. However, static tests may be more useful than flow-through studies as the former are slightly more relevant to the exposure which could occur in the field. An alternative is to conduct a specifically targeted microcosm study with the formulated product to address the long-term risk. There is also scope for extrapolation of toxicity data between similar formulations. Such an approach should be justified in a reasoned case. In the risk assessment, data from long-term/chronic tests with the formulated product should be used for ETR calculations. NOECs should be compared with initial PECs, unless appropriate fate and behaviour data are available which are relevant to the formulated product. Note 5. Predicted environmental concentration (PEC) The Predicted Environmental Concentrations (PECs) are taken from Chapter 6 (Surface water and sediment). The PECs (initial, short- or long-term average concentrations) provide the exposure part of the exposure/toxicity ratio used. The exposure of aquatic organisms to plant protection products depends on the loading to the surface water compartment, which may be via drift, run-off, drainage or atmospheric deposition. Each of these is estimated depending on the situation the risk assessor or the consultant expert considers relevant. Depending on the results of the risk assessment to aquatic organisms, it may be decided to return to the Surface Water and Sediment Scheme to perform higher-tier modelling of the surface-water concentration, fieldexposure experiments, or postregistration monitoring. Note 6. Higher-tier risk assessment During the HARAP international workshop (Campbell et al., 1999), it was agreed that appropriate techniques, intermediate between core data and field trials, are available for higher-tier risk assessment. The objective of the HARAP workshop was to develop guidance principles for higher-tier aquatic risk assessment, i.e. guidance for assessing the risks of plant protection products to the aquatic environment when a preliminary risk characterization indicates potential concerns. Approaches to higher-tier risk assessment discussed at the HARAP workshop include: further single-species studies, laboratory multispecies tests, outdoor microcosm and mesocosm studies. Further single-species studies With respect to further single-species studies, the HARAP workshop identified three possible approaches: (1) acute and chronic tests with additional species (2) modified exposure studies with standard test species, and (3) population-level studies. Data from additional single-species toxicity tests can be used under some circumstances to reduce uncertainty by providing information on the distribution of species sensitivity. The number and type of additional species that should be tested depends on what is known about the mode of action or selectivity of the plant protection product. In general, for compounds which do not appear to be selective to aquatic organisms (those to which all standard test species show a more or less similar sensitivity within an order of magnitude), it is suggested that eight species could be used as a minimum to describe the distribution of sensitivities of aquatic organisms. However, in cases where it is known that a specific group of organisms is particularly sensitive, the species selected for further testing should be chosen from the relevant group. If fish are the most sensitive group, fewer species (at least 5) may be required because of animal welfare considerations and the usually more narrow distribution of sensitivity between fish. The HARAP workshop (Campbell et al., 1999) recommended that probabilistic approaches should be the subject of further research and discussion. However, comparisons of laboratory single-species tests and (semi)field experiments performed with the same plant protection products (Okkerman et al., 1993; Solomon et al., 1996; Giesy et al., 1999; van den Brink et al., 2000) suggest that the 5 10th percentiles from the distribution of the chronic-effect concentrations in single-species tests are predictive of the no-adverse-effect levels in ecosystems under longterm exposure conditions. For further statistical and ecotoxicological considerations of the Species Sensitivity Distribution concept, the reader is referred to the scientific literature (van Straalen & Denneman, 1989; Wagner & Løkke, 1991; Aldenberg & Slob, 1993; Forbes & Forbes, 1993; Aldenberg & Jaworska, 2000; ECB, 2001). If dissipation of a plant protection product is rapid under field conditions, risk assessments based on toxicity studies performed under constant exposure conditions may overestimate potential risks. One approach to modified exposure studies is to alter the test system to allow an important environmental fate process to take place (e.g. addition of sediment to simulate adsorption/degradation processes; natural light conditions to simulate photolysis). The second approach is to simulate the dissipation dynamics of the chemical (derived from exposure modelling or field tests) in a toxicity test by using a variabledosing system. According to the HARAP workshop (Campbell et al., 1999), the same uncertainty factors as used in the preliminary risk characterization should be used to evaluate modified exposure studies with standard test species, since risk reduction from altered exposure is included in the amended effect concentration. Population-level studies are most appropriate when concerns have been identified for a specific organism. These studies, which can include either experimental or modelling studies, may allow conclusions about the potential impacts at the population level and subsequent recovery, rather than effects on individual life-stages. Standard toxicity tests are typically conducted with neonate or juvenile test organisms. According to the HARAP workshop (Campbell et al., 1999), the implementation of these studies into risk assessment needs to be evaluated on a case-by-case basis and will depend on what other data is available. For example, if additional single-species laboratory toxicity tests or field studies have identified a particular species to be at risk (e.g. the most sensitive species tested),

12 Environmental risk assessment scheme for plant protection products 191 the results of a population-level study for that species could be compared directly with the exposure concentrations to determine the potential for effects. Laboratory multispecies tests Indoor multispecies test systems consist either of a set of predetermined species and abiotic conditions chosen by the experimenter (indoor defined microcosms) or of less prescribed assemblages of organisms derived from samples collected in natural ecosystems (indoor semirealistic microcosms). They can be useful for investigating potential risks, or help in the design and interpretation of more complex outdoor tests. In general, indoor defined microcosms are relatively small (several litres) and inoculated with a well-described assemblage of small organisms but characterized by several trophic levels (e.g. primary producers, consumers, decomposers). These test systems may be useful to address concerns identified at lower tiers, at least when phytoplankton and zooplankton are among the most sensitive endpoints. When single-species tests indicate in particular that larger species such as insects, fish and macrophytes are the organisms of concern, other test systems should be considered. According to the HARAP workshop, more guidance is needed on the use of defined microcosm tests in higher-tier risk assessment. Examples of defined microcosm tests are described by Stay (1990). Indoor semirealistic micrcocosms are intended to represent natural assemblages. These derived test systems are usually larger and more complex than defined microcosms, and contain a higher diversity of species. In general, these test systems can include populations of larger organisms like macroinvertebrates and submerged macrophytes. It was concluded by the HARAP workshop that semirealistic microcosm studies may, under some circumstances, be used directly in the risk assessment without applying an uncertainty factor, provided the test systems include relevant species, sensitive end-points and test conditions comparable to field conditions at risk. Many of the fundamental issues relating to semirealistic laboratory microcosms also apply to equivalent outdoor studies in microcosms and mesocosms. Some examples of indoor semirealistic microcosm tests with pesticides are described by Breneman & Pontasch (1994), Fliedner et al. (1997) and van den Brink et al. (1997). Outdoor microcosm and mesocosm (multispecies) tests Tests in outdoor microcosms or mesocosms are useful in risk assessments when lower-tier and higher-tier laboratory studies indicate potential risks. The preceding laboratory studies help to focus the (semi)field tests in microcosms or mesocosms. Micro/mesocosm studies are especially suited for determining the ecological relevance of effects identified in laboratory studies. Interpretation of these studies focuses on responses of dominant populations, community level effects, potential indirect effects and the recovery of aquatic populations and communities. A second important reason for conducting micro/ mesocosm tests is to measure the environmental relevance of certain fate processes, and to evaluate environmentally realistic exposure conditions. Every study should be designed with a specific purpose in mind, determined by the conclusions of preceding risk assessments. Each study is unique in at least some respects. A good summary of the general approach to this type of testing is given by Crossland (1990). Guidance for conducting field studies is therefore necessarily generic and flexible. The Monks Wood (SETAC-Europe, 1991), Wintergreen (SETAC/RESOLVE, 1991) and EWOFFT (1992) guidance documents, and the draft guidance documents of OECD (2000b), are useful for establishing appropriate study designs. In the present subscheme, there are two types of (semi)field tests which can optionally be required, depending on the situation, viz., short-term and long-term micro/mesocosm tests. By definition, short-term trials are relatively short (up to approximately 1 3 months) and mainly attempt to measure direct effects of single applications, crude disappearance half-lives under seminatural conditions, and indirect effects and rate of recovery of populations with short life-cycles. It might also be permissible to study similar effects in laboratory-scale microcosms (particularly for small organisms such as algae and zooplankton). Long-term (semi)field tests are much more complex, time-consuming, expensive and difficult to interpret than shortterm trials, but are designed to confirm whether predicted chronic effects (e.g. due to repeated application), bioaccumulation, or expected fate actually occur under reasonably realistic field conditions. They also allow long-term observations on interactions between species (e.g. indirect effects) and recovery of populations with a more complex life-cycle. A literature review of indoor and outdoor freshwater micro/mesocosm tests performed with herbicides and insecticides, describing the types of effects that can be observed in these tests systems, is presented by Brock et al. (2000a,b). The ecological interpretation of aquatic microcosm and mesocosm data, and implementation of these studies in regulatory risk assessment, were recently discussed at the CLASSIC Workshop (Community Level Aquatic System Studies-Interpretation Criteria). Recommendations can be found in the proceedings of this workshop (Giddings et al., 2002). Although several problems were recognized when using micro/mesocosm studies for regulatory purposes, it was concluded that, where these studies are appropriately designed, conducted and evaluated, an ecologically acceptable concentration can be derived from them. Ecological criteria (e.g. potential for recovery; ecological role of affected populations) should be taken into account when deriving acceptable concentrations. In addition, it is important to have transparent legal, political or societal protection aims for the types of aquatic community actually at risk. Note 7. Sediment toxicity A sediment toxicity test is required if the test substance is expected to partition into sediment, persist there, and exert chronic toxicity to Daphnia (as an assumed surrogate for all