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Part 7 – Environment

1. Introduction

This chapter sets out the requirements for submitting environmental data as part of applications for:

1. registration of an agricultural chemical product;
2. variation/extension of a registration of an agricultural chemical products; or
3. applications for a permit to use an agricultural chemical product.

Environmental data are generally evaluated by the Environment Protection Branch of the Department of Sustainability, Environment, Water, Population and Communities (DSEWPC) who then advise the APVMA. The data provide information on the expected volume, exposure, behaviour and fate of the active constituent(s) when the agricultural chemical product is used as proposed, and on the potential harmful effects on birds, mammals, fish, terrestrial and aquatic invertebrates, algae plus aquatic and terrestrial plants. This information is important in establishing whether the risk posed by the proposed use of the product to any of these organisms may be considered unacceptable or whether there are other concerns due to the behaviour of the substance in the environment.

This chapter lists a very broad range of data elements. However, in many cases the data that are required to be submitted will be a subset of these, and should be tailored to the nature of the proposed application and the anticipated environmental exposure pattern. Decisions regarding which data is required are based primarily on the expected environmental exposure. It is unrealistic to prescribe uniform data requirements for environmental assessments, as agricultural chemical products vary widely in their environmental properties and in the ways that they are introduced into the environment. Considerable variation in the nature of the receiving environment can also be expected for different applications. This will be discussed in more detail in Section 4 of this chapter.

1.1 Reference materials

The details of documents referred to in this chapter (including codes and standards) are given in the References section. Applicants should be aware that many of these documents are updated regularly, and thus should endeavour to ensure that the latest edition is used.

The Environmental Risk Assessment Guidance Manual for agricultural and veterinary chemicals (referred to in this document as the “Risk Assessment Manual (RAM)”, developed through the Environment Protection and Heritage Council (EPHC), is a useful document that provides more detailed explanations of how data are used in the assessment process. This may be located on, and downloaded from, the EPHC web site (last accessed April 2010).

“Guidelines for the Registration of Biological Agricultural Products” is a useful document that provides more detailed guidelines when registering biological agricultural products.

2. Overview of the Assessment Process

Under the legislation pertaining to agricultural and veterinary chemical registration, in granting or refusing an application the APVMA needs to consider whether the proposed use of an active constituent or product in accordance with the instructions for its use may have unintended effects that are harmful to “animals, plants or things or to the environment” (see the Agricultural and Veterinary Chemicals Code Regulations under the APVMA Legislative Framework). It is the Environment Protection Branch in DSEWPC that generally provides advice to the APVMA on environmental aspects of applications.
The practices used in undertaking environmental risk assessments for the APVMA are described in the RAM. Environmental risk assessment consists of:

1. an exposure assessment to arrive at a predicted or estimated environmental concentration (PEC/EEC) – to do this considerations include the method of use of the product, scale of use, situations in which the product is used, and fate of the active constituent in the environment. Various models may be used for which specific information is needed, e.g. to estimate concentration in surface waters from spray drift or runoff. For existing chemicals monitoring data may also be considered;
2. an effects assessment to identify and classify the hazards to the environment and to arrive at which are the most sensitive end points in the various compartments;
3. risk characterisation, relating the PEC/EEC to the most sensitive end points to determine whether or not the risk is acceptable, and if not, considers if/how risks may be mitigated by appropriate label advice or other action (see Figure 2‑1).

In Figure 2.1 Q is the (most sensitive) end point divided by the predicted (estimated) environmental concentration (PEC/EEC).  For agricultural chemicals the acute Q needs to be <0.1 as there is an inbuilt assessment factor of 10 (see p75 of the RAM).  The same relationship is also used for chronic risk assessments, except that NOECs/NOELs rather than LC/EC/IC/LR50s (depending on the end point), and the chronic PEC/EECs are used, together with the Q needing to be <1.

In addition to evaluating toxicity hazards to non-target organisms, the assessment needs to consider whether there are other concerns due to the behaviour of the substance in the environment, including persistence in soil, sediment, water or the atmosphere, bioaccumulation, potential to move into groundwater, or for volatile/gaseous substances, potential to affect the ozone layer or act as a greenhouse gas in the atmosphere.

In assessing risks to the environment, consideration is given to the whole life cycle of the active constituent. Consideration is given as to whether there is any environmental exposure in Australia as a consequence of the manufacture of the active constituent or formulation and packing of the product. Assessment of the fate of the active constituent once released to the environment includes consideration of:

1. the rate of degradation;
2. the means by which degradation occurs;
3. the identity and amount of degradation products produced and their further degradation; and
4. the mobility of the active constituent and major metabolites.
   
   If significant metabolites are produced during degradation it is necessary to conduct an effects assessment to identify and classify the hazards to the environment they represent.

Figure 2-1 The iterative approach to determine risk acceptability

As well as assessing data provided by the applicant, consideration is also given to information available from other sources, such as literature searches and foreign environmental agency reports (e.g. United States Environmental Protection Agency (US EPA) or European Food Safety Authority (EFSA) reports).

2.1 Environmental Risk

As stated above, the risk assessment is a synthesis of the results from the evaluation of the exposure and the toxic effects. Depending on the degree of environmental hazard, consideration may be given to actions to minimise the environmental risk. The assessment of the environmental hazard may result in requests for further environmental data (e.g. monitoring trials). To further minimise environmental risk, APVMA may also impose:

• Specific restrictions (e.g. Do not apply on steep country above 20% or 11 degrees); or
• Other label instructions and warnings (e.g. Toxic to fish and other aquatic organisms).

Having considered an overview of Australia’s environmental risk assessment process, the following section considers the specific data requirements to enable a full environmental risk assessment.

3. Types of Applications

Applications that trigger environmental assessment requirements may fall into one of three environmental modules: modules 7.1, 7.2 and 7.3. The main distinction between the three modules relates to the resources required for their evaluation. Environmental assessment may also be required for some of the fixed categories listed in Ag Volume 2 of MORAG.

The nature of the application determines which Part 7 (Environment) data module is required. Each module refers to the same broad set of environmental data elements, but the actual data elements required varies depending upon the nature and extent of environmental exposure from the proposed use pattern and the anticipated environmental behaviour of the product.

4. Data Requirements

The environmental data required for an application depend largely on the expected environmental exposure. All of the data requirements discussed in this chapter must be complied with. Where data to address a specific requirement is not submitted, applicants must request a data waiver against the specific requirement and justify the waiver with a valid scientific argument, for example, by demonstrating that environmental exposure to this group of organisms will be minimal.

4.1 General requirements

The APVMA has adopted the OECD dossier numbering system as outlined in Section 6.1. Applicants must provide all registration applications in this format, however if an applicant  chooses they can provide a full OECD formatted dossier. Detailed guidance to further assist registration applicants in complying with the OECD dossier format is available from the OECD website (last accessed April, 2010).

The OECD format is unlikely to be relevant for the limited data submissions for module 7.3 applications. Therefore, for module 7.3 applications, applicants are required to fill in the appropriate APVMA form as the template.

Quality of submitted studies

Data quality directly influences how confident risk assessors can be in the results of a study and the conclusions they may draw from it. Therefore, environmental fate and toxicity studies must be of sufficient quality for the study to be relied upon for regulatory decision-making. The process of determining the quality of data takes into consideration three aspects - adequacy, reliability and relevance of the available information to describe a given assessment end-point. Detailed information on how the quality of studies are determined and rated can be found in Chapter 4 of the RAM. Studies must be of sufficient quality to achieve either a rating of “1 Fully reliable” or “2 Reliable with restrictions” according to the OECD approach as used by DSEWPC, as described in Chapter 4 of the RAM.

Level of documentation

The documentation must be complete, well organised and be presented in sufficient detail (for example, inclusion of raw data on concentrations measured or individual animal responses) to allow independent scientific assessment. Copies of original reports must be supplied. Summaries, or reprints of published material, usually do not contain sufficient detail and will, therefore, only be accepted if they contain sufficient detail to allow independent scientific assessment and achieve an acceptable reliability rating.

Request for waiver of data requirement

Where an applicant believes a particular data element is not necessary, the applicant must maintain the data heading, request a data waiver for the specific data element and provide a valid scientific argument as to why the data is not required. In some circumstances, model data based on Structure-Activity Relationships (SAR) may be accepted in lieu of test reports, particularly where models have been validated.

Adverse reports

Applicants must not omit reports, including published material, which could adversely influence the outcome of an environmental risk assessment. If the applicant considers that such reports reach unsupportable conclusions, they should clearly state the justification in the application.

Details of other regulatory applications

The application must include details of any regulatory applications for the same product made to other regulatory bodies, either in Australia or overseas. Where available, the results of those applications and subsequent regulatory decisions (e.g. copies of assessment reports, or links to where these and/or regulatory decisions may be found) must be provided. If any data in the submission have been rejected by an overseas regulatory body, the applicant must identify this and provide justification to support the inclusion of the study in question.

Formulation data

Formulation toxicity is an important consideration, noting that with the move to the OECD format formulation data is covered in Parts III A 9 & 10.  DSEWPC usually prefers data on the active constituent, for example for aquatic toxicity, but formulation data are more important for toxicity to honeybees, non-target arthropods and non-target vegetation as these are directly contacted by spray or spray drift, as opposed to water or soil where there is more time for the formulation components to separate before exposure occurs.  If results are available for both, DSEWPC will use the most sensitive value in its risk assessments.

4.2 Chemistry and manufacture

Applications which require environmental data will also require Part 2, Chemistry and Manufacture data. This is because details of the chemical and physical properties of the active constituent, in particular, are necessary to allow complete environmental evaluation of the product. This can be particularly important for Reduced and Limited assessments (Modules 7.2 and 7.3, respectively), where both environmental fate and effects may be inferred from, for example, data on water solubility and partition co-efficient.

4.3 Data elements – basic requirements

The data elements that must be complied with for environmental risk assessment include:

• Fate and behaviour in the environment (environmental exposure); and
• Hazard: effects on non-target species (environmental hazard).

Environmental fate and behaviour

Environmental fate and behaviour data describe the degradation of active constituents, through abiotic and biotic mechanisms, and their mobility and likely transport and final destination in the environment. The data are used to help estimate the predicted environmental concentrations in different environmental compartments (vegetation, soils, sediment, water, air and animals), as appropriate, based on the proposed use pattern and physico-chemical properties of the chemical.

Environmental effects

Environmental effects data are obtained from tests on standard organisms, representing organisms that are likely to be exposed to the agricultural chemical product or to residues arising from its introduction into the environment. These data are used in conjunction with the anticipated environmental exposure and environmental fate data to determine the potential risk to non-target organisms, and the need for precautionary label statements or other risk management measures to minimise the potential for harm.

Non-target species

Tests for effects on non-target species include short term acute, subacute, reproduction, simulated field and full field studies. A hierarchical or tier system is used, under which the results from lower tier laboratory tests are used to determine the need for higher tier testing, such as full field studies, based on the potential for the chemical to cause harmful effects.

4.3.1 Data elements for OECD format

The APVMA has adopted the OECD dossier numbering system as outlined in Section 6.1. Applicants must provide all registration applications in this format, however if an applicant choices they can provide a full OECD formatted dossier. Detailed guidance to further assist registration applicants in complying with the OECD dossier format is available from the OECD website (last accessed April, 2010).

The OECD format is unlikely to be relevant for the limited data submissions for module 7.3 applications. Therefore, for module 7.3 applications, applicants are required to fill in the appropriate APVMA form as the template.

Individual data elements and the circumstances in which they are likely to be required are discussed in more detail in Section 4.4 below.

4.4 Elements that may be needed for any particular application

The level of data required for a submission is generally proportional to the potential for environmental exposure arising from the proposed use pattern. For example, any proposal that includes broadacre use will generally require the full data set, unless DSEWPC has previously assessed the chemical. If this is the case, the data set would only need to be updated and supplemented as required.

The use pattern, together with its scale of use, type of formulation and mode of application, however, could modify the data requirements and is now discussed.

4.4.1 Factors determining data requirements

Table 4‑1 gives an idea of the potential for environmental exposure arising from four factors related to exposure. Each column is arranged in approximate decreasing order of potential environmental exposure, from high at the top, to low at the bottom. This may be used as an indicator of the extent of environmental data likely to be required.

Table 4‑1 Factors relating to environmental exposure

		Use Pattern	Scale of Use	Formulation	Application
Potential Environmental Exposure	More	Grain and fibre crops	Broadacre	ULV	Aerial
		Fruit crops	Multiple applications	EC	Mister
		Vegetable crops			Boom
	↑	Forestry	Irrigated crops	Fumigants
	↓	Pasture and seed crops	Single application	WP	Baiting
	Less	Antifoulants, rodenticides		Granules	Seed dressing
		Glasshouse crops and turf	Small acre
		Premises	Home gardens	Individual baits	Backpack

The following scenarios are provided to demonstrate data requirements for various levels of environmental exposure. These scenarios are not exhaustive, and are indicative only. However, they may be used as an example and a guide for the applicant’s decision-making process. Additionally, applicants are encouraged to contact the APVMA to request pre-application advice.

Variations in data requirements – example scenarios

The applicant, when addressing the data requirements, may decide that a particular data element is not needed, or needs only minimal data, because of use pattern or indications from other data. For example, if the chemical’s volatility is low, then dissipation in air studies would not be required, or if acute toxicity studies indicate it is practically non-toxic, then short-term and chronic studies may not be needed, unless it was persistent, or there are good reasons to suggest the acute chronic ratio is very high, such as with insect growth regulators. This reason or scientific argument for the waiver of data must be clearly stated.

The mode of application, as illustrated in the examples above, can often decide the extent of environmental exposure. For instance, if the chemical is to be aerially sprayed, then the data requirements (both fate and toxicity) are likely to be high because of the potential, from this application route, for widespread environmental exposure to non-target areas and non-target organisms. Misters or air-assisted sprayers in orchard situations are also likely to have potential for widespread environmental exposure to non-target areas and therefore require a similar degree of fate and toxicity data.

Scenario 1: Insecticide:

Use Pattern	Scale of Use	Formulation	Application
Grain and fibre crops	Broadacre	ULV	Aerial

For example, an applicant wanting to register a new insecticide, which is aerially sprayed onto broadacre crops, will need to address all data elements, given the wide dispersive exposure pattern. In addition, the applicant would also need to place special emphasis on the potential for overspray and spray drift, as well as for run-off in the irrigation water and the effect on non-target invertebrates.

For crops where Integrated Pest Management (IPM) is routinely practiced, such as pome fruits, non-GLP screening studies may be useful in addition to the standard laboratory tests. Non-target organisms that must be considered include bees and earthworms, predators, parasites, and detritus feeders. Field efficacy studies addressing impacts on non-target organisms or screening tests for activity of metabolites will also be useful for environmental assessment.

Scenario 2: Herbicide:

Use Pattern	Scale of Use	Formulation	Application
Grain and fibre crops	Irrigated	EC	Boom

In contrast to Scenario 1 above, an applicant registering a herbicide to control pre-emergent weeds, which will be sprayed as a blanket spray by low boom spray, with a coarse spray (VMD 341 µm). Based on the proposed crops for which this will be applied, the soils are expected to range from a light sandy loam to heavier silt loam. Clearly in this scenario, the chemical has the potential, if moderately water soluble and applied at a high rate, to move in surface waters or leach to groundwater while the potential for spray drift is comparatively low.

Ecotoxicity tests for at least 4 algal species and Lemna spp. must be included for all herbicides and fungicides due to the potential for harm to these species to these types of pesticides (Fewer data points may be adequate for other types of pesticides).

Sugar cane, cotton or summer grain crops that are irrigated, even if the product is applied by boom spray, would require most of the fate data requirements to be addressed because of the potential for movement off-site in surface water (either as release of tail waters or storm water). The data must be reflective of soils typical for the area, for the latter cases most notably the heavy cracking clays.

Scenario 3: Insecticide/Fungicide Seed Dressing:

Use Pattern	Scale of Use	Formulation	Application
Grain and fibre crops	Broadacre crop	EC	Seed dressing

In contrast to Scenario 1 is if the formulation was a granule or the application was as a seed dressing, as this does not allow a high degree of drift or spread of the chemical off target. However, there would be a greater requirement for avian toxicity studies because of the greater potential for poisoning birds from ingesting granules and treated seeds.

Scenario 4: Residential/Commercial Rodenticide:

Use Pattern	Scale of Use	Formulation	Application
Antifoulants, rodenticides	Single application	Individual baits	Baiting

If the product is a rodenticide and put out as a field bait, then avian and non-target mammalian toxicity data would be needed, but little aquatic data because exposure to aquatic life is expected to be very low when the bait is used according to label directions. If it is used on residential or commercial premises, then avian and non-target mammalian toxicity data requirements are potentially lower due to the lower environmental exposure. However, some data is still required, particularly for anticoagulants due to the length of time taken for the target animal to die, and the potential for dead or dying animals to move into the open.

Scenario 5: Poultry shed insecticide:

Use Pattern	Scale of Use	Formulation	Application
Premises	Single application	WP	Backpack

A poultry shed insecticide requires a basic set of environmental chemistry and fate, as well as some biodegradation (i.e. metabolism/transformation) studies, especially those performed using relevant (i.e. soil) test systems. A request for data waiver for mobility studies (particularly for spray drift, and possibly volatility and leaching potential) could be justified with a suitable argument as it will be applied to building surfaces, with an expected very limited exposure to soil. If, however, the insecticide was expected to contaminate chicken litter (e.g. because of different management practices or use pattern), then more biodegradation, mobility and field dissipation studies would be expected because of the potential use of the litter as a fertiliser. Similarly, only a limited set of environmental toxicology would be needed because of its generally low environmental exposure, unless it contaminated litter and this was subsequently used as a field dressing.

Other Issues

For chemicals (and their major degradates - defined as >10% of applied) that may persist in the environment (identified through laboratory studies on hydrolysis, photolysis, metabolism studies, and frequency of application), field accumulation studies will be essential, particularly if exposure is high, and there is likely to be carry over of residues in soil etc between years or seasons.  This can be tested through the use of some basic modelling using the half-life (see Chapter 5 of the RAM). In this case, the scale of field use (i.e. broad acre versus glasshouse) is not sufficient justification to request a data waiver of these data elements, as a chemical might be very persistent, used at high rates and mobile, therefore of possible concern in its potential to accumulate and/or leach to groundwater, even if used in glasshouses.

All data generated from field dissipation studies, or other studies performed for ‘realism’ or ‘environmental relevance’ such as micro- or mesocosms, must use the appropriate formulations to be used in Australia to be of value in assessing the risk of the active constituent.

In summary, active constituents in products that are used in broad scale applications are likely to require all elements, and it is mainly in the specialty areas that a data waiver for certain data elements may be applicable.

Other areas of toxicity testing

The data requirements in areas of environmental risk assessments which have emerged over the past decade include:

• information on non-target terrestrial plants, of which data for herbicides are particularly relevant, but is also important for fungicides; and
• sediment testing, which is also a relatively new emerging and important area of toxicity in the aquatic environment and is particularly important for insoluble persistent pesticides. As noted in Chapter 6 of the RAM, the route of exposure is an important factor. Where exposure is primarily through chemical bound to soil/sediment (for example, run-off in the sorbed state), data based on OECD TG 218 are more appropriate as the test is performed with the substance pre-mixed with the test sediments. However, in the case of exposure directly to the water column (for example through spray drift), data based on OECD TG 219 using spiked water should be generated.

Combination toxicity testing

Combination toxicity data is required for formulations containing two or more active constituents, to allow assessment of any increased toxicity from the combination product. Data will also be required for all deliberate (mandatory) tank mixes where the draft label’s Directions for Use or Critical Comments says “must always be applied with X”.  This can be in all applications or only in certain circumstances.  It will not be required if it is only on another part of label which says – “Compatible with….” or “May be tanked mixed with….”.

The extent of combination toxicity required will depend on both on the exposure and toxicity.  Examples are: a seed dressing may not require combination aquatic toxicity, for birds combination toxicity may not be required if toxicity of both actives is low, or for aquatic toxicity if one active constituent’s toxicity swamps the other.  Further for aquatic toxicity if one group (say algae) is 100X more sensitive for both actives, only that level needs be tested.  However, if the most sensitive taxonomic groups for the individual actives constituents are not the same, formulation data is required for all three groups (see RAM, p44).

5. Data Evaluation and Guidelines

Applicants are expected to conduct their own environmental risk assessment, based on the expected environmental exposure arising from the proposed use volume and pattern, and the data or argument submitted to address relevant data elements. This assessment is essential, as it identifies which data elements require particular attention, and whether the data package contains sufficient information to be accepted for evaluation by the APVMA. The risk assessment forms part of the crucial determination of which elements are required for a particular application, as described in Section 4.4 above.

This risk assessment corresponds to point 6.8 (environmental risk mitigation) in the tier III overall summary and assessment known as Document N under the OECD format. The risk assessment must be based on a concise summary of the data presented in the active substance and formulated product dossiers, supported with a statement of the applicant’s overall assessment of the dossier and the conclusions which the applicant believes should be reached on the basis of the data and information provided. The statement must have regard to the weight of the evidence available (the extent, quality and consistency of the data) and the criteria and guidelines for environmental evaluation and decision making used by the APVMA. These criteria and guidelines are described below.

Three Step Process

Environmental risk assessment is a three step process. An environmental exposure assessment is first conducted, in order to determine the concentrations of the chemical that are likely to occur in the environment. Toxicity data for organisms that are likely to be exposed, based on the exposure assessment, are then evaluated in an environmental effects assessment, in order to determine the concentrations that are likely to be harmful to these organisms. The exposure and effects assessments are interdependent, in that the exposure assessment will determine which data elements are required for environmental effects, while the effects assessment will determine the level of detail and refinement required for the exposure assessment. Environmental risk assessment integrates the outcomes of the exposure and effects assessments to determine whether the use of the chemical according to label directions likely to be harmful to non-target organisms in the environment.

The procedures followed for environmental risk assessment are discussed in more detail below. The discussion is deliberately presented from a general perspective, as it is unrealistic to prescribe a specific procedure given the variability of environmental exposures and risks across different products and use patterns. Further, some product types, such as antifoulants, have very specific data requirements that do not pertain to crop protection chemicals. Such examples will be presented in more detail at Section 5.2 below, after the more general discussion of data evaluation procedures.

5.1.1 Environmental exposure assessment

The amount of chemical likely to be released to the environment is a central tenet of environmental exposure assessment. DSEWPC considers the chemical in the context of ‘cradle-to-grave’. The assessment will determine which compartment(s) of the environment (air, soil, water and biota) will be exposed to the chemical, and the likely level of exposure through its use as stated on the proposed product label and predicted market volume. This includes consideration of environmental exposure arising from the manufacture or formulation, and from disposal of excess or spent chemical (for example, dipping solutions, after appropriate treatment), unused product, and empty containers.

Amount of chemical to be used

The estimated quantity (in tonnes or litres) of chemical/product to be imported, manufactured, formulated or repacked up to and including market maturity must be provided.

Manufacturing plant (active constituent) and formulating plant (product)

For active constituents where the manufacturing plant is located in Australia, and for all product formulation and packaging processes taking place in Australia, the applicant must provide a brief summary of the following:

1. details of release of the chemical to the environment resulting from all manufacturing, formulation and packaging operations (e.g. from disposal of bulk containers and rinsings from cleaning machinery). This will include total amounts released to water, air and land, concentrations in effluent streams, and the control technology used to minimise release; and
2. proposed means of disposal of waste product arising from manufacturing, formulation and packaging operations (e.g. spilled material and off-specification batches).

Use and application

To accurately assess the environmental hazard, the applicant must provide information about label claims (uses) and application methods to determine which environmental compartments are likely to be exposed to the chemical. Therefore, information on the following is required:

1. details of the method of application (e.g. granules incorporated into the soil; type of spraying: ground directed, ground boom, ground misting, aerial; baits/lures; fumigation; dipping, etc);
2. details of factors influencing mobility or transport/spray drift of the product (e.g. droplet size, equipment used, nozzle type(s), size(s), pressure range and angle); and
3. fundamental characteristics of the environment which may influence transport and degradation of the chemical (e.g. irrigated pasture or crop, type(s) of irrigation, soil types and range, rainfall, cropping system and area under cultivation to that crop, etc).

Crop profiles are particularly useful when the active constituent is only proposed for restricted uses or limited applications, as the characteristics of the environment can play an important role in deciding the amount of fate and toxicity data required.

Product disposal

Information must be provided on disposal of:

1. empty containers;
2. unused product; and
3. diluted-for-use chemical.

The applicant should consider developments in these areas. The National Farmers Federation (NFF), CropLife Australia, Animal Health Alliance (Australia) Ltd, VMDA and the Australian Local Government Association (ALGA) have together developed the initiative, the Industry Waste Reduction Scheme (IWRS) as the solution to the safe collection and recycling of cleaned chemical containers and the collection of unwanted rural and agricultural and veterinary chemicals.

General label statements for the proper disposal of product and used containers can be obtained from the Ag Labelling Standard. Furthermore, part of DSEWPC’s assessment and advice to the APVMA may include appropriate label disposal instructions for the particular product under assessment.

Spent dipping solution disposal

1. Half-life in soil <10 days at the likely concentrations following dip disposal;
   AND/OR
2. The active(s) must be able to be denatured safely, quickly and completely (>98% in 2 hours) prior to disposal.
   AND
   
3. If repeat applications are to be made to the same site and denaturing is not possible, these should not occur until 4 half-lives have passed.
4. The spent dip should be evenly spread over flat land at a rate not exceeding 100,000 L/ha for spent sheep dips and 20,000 L/ha for spent fruit dips.
5. The disposal site must be dedicated and adequately bunded (soil at least 15 cm high).
   

Whilst an examination of the data holdings and label statements of all current active constituents and their associated products used in dipping is currently being undertaken, any application for new active constituents or extension of existing actives and associated products to be used in dips will need to be accompanied by data in the above areas to allow assessment of whether disposal to land is feasible and/or the drafting of suitable label statements.

Predicted Environmental Concentration (PEC)

Chapter 5, Environmental Exposure Assessment of the RAM provides a more detailed discussion of this area, providing guidance and more details of the range of environmental chemistry and fate tests, and in particular provides details for the determination of estimated or predicted environmental concentrations (PECs).

A key element of the exposure assessment is the spray quality, as this is one of the determinants of drift, and a key input in models used to estimate the amount of drift at different distances from the point of application. Spray quality parameters need to be clearly defined on product labels. Applicants should refer to the APVMA’s Operating Principles in Relation to Spray Drift Risk.

PECs in water, air, soil, vegetation and/or animals will need to be estimated, depending on the use pattern. If no such exposure is expected in any compartment, applicants can request a data waiver and provide this as an argument for not providing particular data elements. For example, aquatic exposure would not be expected from the use of household rodenticides. Therefore, toxicity data for aquatic life would not be required for such an application, although applicants must provide such data if available.

Tiered PECs

The exposure assessment is a stepwise or tiered process, under which PECs are first determined under worst case conditions using simple screening models. If the initial PECs are at harmful levels, based on the environmental effects assessment, they are progressively refined to reflect more realistic exposures. In this way, the analysis for a particular chemical will be kept to a minimum, allowing resources to be directed towards chemicals with the greatest potential for causing ecological harm.

PEC_Water - Spray drift

The initial estimates of the predicted aquatic concentrations are based on the scenario of direct application to a 3 m wide water body that is 15 cm deep at the maximum proposed rate. Short term (acute) PECs will need to be supplemented with long term (chronic) PECs if the chemical is persistent or applied repeatedly within a season. These estimates are then refined as necessary to reflect exposure through spray drift, again with progressive refinement from an initial worst case assumption that this represents 10% of the maximum proposed rate. More realistic exposures are then modelled as needed. For ground based application, AGDRIFT is used, while exposure from aerial application is modelled using AGDISP. These models are used to determine the buffer distances necessary to protect sensitive downwind habitats, such as aquatic environments or areas of native vegetation.

PEC_Water - Run-off and drainage

pray drift may not be the most significant route of aquatic contamination for many chemicals, particularly those that are persistent and mobile, and are widely used within a catchment. An OECD based model (Probst et al 2005), which considers the edge of field concentration, has been developed and will be used in future. The model considers that the application rate, topography, in particular slope of the field to which the pesticide is applied, the magnitude of the rainfall and run-off events, the persistence and mobility of the chemical are the most important factors. Additionally placement of the pesticide, an allowance for the heterogeneity of fields and pesticide bound to suspended sediment are also considered. Based on data available, the model considers a worst case scenario of a 100 mm rainfall event with 20% of that water running off. On a hectare basis this results in 200 m3 of run-off water. An initial screen that does not consider the properties of the chemical is performed. Depending on the likely topography of the cropping scenario, the run-off water is assumed to carry 5 or 10% of the applied chemical, once heterogeneity of the field is allowed for. Consideration is given to the interception and retention of the applied chemical by foliage for foliar applications.  Suspended sediment bound pesticides are generally only considered for sparingly soluble chemicals with solubility < 1 mg/L. This screen can be used to exclude low risk chemicals from further consideration.

Refined Run-Off PECs

If the predicted aquatic exposure from the screening model for run-off indicates that aquatic organisms may be exposed to harmful concentrations of the chemical, the assessment of the edge of field concentration will need to be refined. Exposure scenarios for run-off and drainage are more complex than those for spray drift because the properties of the chemical and of the soils where it is used will influence the mobility and stability of the chemical, and consequently the levels of aquatic exposure. The model assumes 3 days degradation of the chemical and the Kd value, usually based on the Koc of the chemical and the organic carbon content of soil as determined by (ANRA 2001). The modeled refined “edge of field” concentration may also be compared with any actual studies of run-off of the chemical of interest. Dilution of the “edge of field” water is considered in 1500 m3 of environmental water, which is equivalent to a 1 ha water body 15 cm deep or the daily flow of a low flow primary stream. Initially it is assumed that the water body is entirely fed by a 10 ha field 100% treated at the maximum rate. Further refinement of the model considers partitioning of the chemical to sediment using the same model as that used for determining the PECsediment as outlined in the RAM.
A worked example has been added in the Attachment.

The model is being further developed to consider the fate of the chemical in water and more hydrologically realistic catchments, which consider the likely use pattern of the chemical in the catchment.

PEC_Sediment

As noted above for hydrophobic chemicals, rapid partitioning to the sediment may be expected. The PECSediment may be estimated from the PECWater based on the partition coefficient. More information about estimating the PECSediment can be found in the RAM.

PEC_Soil

PECs in soil are usually based on the maximum proposed application rate, as effects on soil organisms in treated areas need to be evaluated. A soil depth of 10 cm is generally assumed, but this may be decreased for chemicals that sorb strongly to soils, or increased for more mobile chemicals. PECs in soil can be refined where needed by considering the persistence of the chemical in soil. Similarly, the PECs in off-target soils can be refined based on modelling of spray drift. Measured data are generally preferred over model outputs and may replace the model predictions where necessary.

PEC_Food

Concentrations on vegetation are estimated using the modified Kenaga nomogram (Pfleeger et al., 1996). The nomogram may also be used, with qualification, to estimate residues on insects. These estimates are used to evaluate dietary risks to non-target organisms such as birds and mammals. The highest residues generally occur on foliage, and can be used as the basis for an initial risk assessment based on the assumption that only treated foliage is consumed. The risk assessment can be refined as needed, for example by considering a more realistic diet including insects as well as vegetation. The nomogram can be used to estimate residues on insects, based on those for fruits and seeds, but caution is needed as there are limitations in using fruits and seeds as surrogates for mobile organisms such as insects.

5.1.2 Environmental effects assessment

Chapter 6, Environmental Effects Assessment of the RAM provides a detailed discussion of this area, including the very wide potential range of environmental effects tests.

Again the amount of data required is likely to be dependent upon the extent of exposure to the various environmental compartments (air, water soil, sediment and biota including plants), and the toxicity of the active constituent and products containing it to organisms inhabiting these compartments. If the exposure is low to a particular compartment, limited data will be needed, particularly if the toxicity to representative organisms from the compartment is also low. Conversely if the exposure to a particular compartment and toxicity to representative organisms inhabiting this compartment are both high, a much more extensive suite of toxicity tests is required.

Formulations, combinations and tank mixes

Toxicity information on the formulation to be used is also an important consideration, including for combination products to clarify whether the toxic effects exerted by the different active constituents are additive or not. As noted above, toxicity of the mixture must also be addressed in the case of deliberate tank mixes where the label instructs that for general, or for a particular use, the product and its active(s) must always be mixed with another different active constituent contained in existing products.

Toxicity to non-target terrestrial plants

The discussion and guidance on the emerging area of toxicity to non-target terrestrial plants must also be noted, in particular the need to extrapolate from a limited set of tested plants, usually other crop species, which emphasises the value of obtaining incident data during trialling and testing the active constituent and its proposed formulations.

QSARs vs. field testing

The RAM also mentions the possible use of QSARs. As noted these are generally less useful in predicting toxicity of pesticides as opposed to industrial chemicals due to their relatively complex structures and that they have specific modes of action not easily incorporated into general structural relationships. Their use requires verified models.

On the other hand field testing such as microcosms or mesocosms are potentially very powerful tools in defining toxicity in actual or real life situations, in particular testing any mitigating effects such as reduced toxicity in the presence of sediment as opposed testing in clean laboratory tanks or vessels. Field testing is the preferred approach.

5.1.3 Environmental risk assessment

Chapter 8, Risk Characterisation of the RAM provides a detailed discussion of environmental risk assessment. The basic principles of which are outlined below. Applicants are encouraged to consult the RAM for further detail or clarification. Please note, however, that this chapter of the RAM is not in the order of the internationally agreed OECD format.

Risk Quotient (RQ) Method

The approach followed for environmental risk assessment is based on that used by the US EPA, as originally developed by Urban and Cook (1986). This is often referred to as the quotient or Risk Quotient (RQ) method. It compares the PEC as the numerator with the toxicity as the denominator. Acute toxicity is usually expressed as the median lethal or effect concentration, LC50 or EC50. For plants, a more sensitive measure (e.g. the EC25) may be used. Chronic toxicity is usually expressed as the NOEC. The objective is to ensure that the quotient does not exceed levels of concern.

Toxicity Exposure Ratio (TER) Method

The approach followed by the European Union entails the determination of the toxicity exposure ratio (TER) which is the inverse of the quotient. Under this approach, the TER must be maintained above levels of concern. Whilst the APVMA would prefer that applicants use the Risk Quotient method, it will accept risk assessments based on the TER approach, particularly for major data submissions in the agreed OECD format.

Level of Concern (LOC)

The level of concern (LOC) generally adopted by the APVMA for risk assessment of acute toxicity to aquatic organisms (fish, invertebrates, algae and aquatic plants), terrestrial animals (birds, mammals and invertebrates) and plants is 0.1. As noted in the comparison tables in Section 8.9 of the RAM this is often more conservative than the approach of the US EPA, though the US EPA’s level of concern (unity = 1.0) for chronic toxicity is adopted by the APVMA. This contrasts with the stricter LOCs adopted by the EU.

The iterative approach

When assessing risk it is generally the situation that every case cannot be accounted for, so the applicant should follow an iterative process (refer to Section 2 for example) by considering:

• a “worst case” scenario such as a direct overspray to shallow water; and if needed,
• a series of refinements which account for other factors and results in setting more realistic scenarios at each step, such as the 10% spray drift followed by spray drift modelling (refer to Figure 2‑1 above).

Mitigating risk

Where levels of concern are exceeded, the applicant will need to propose measures such as label instructions to mitigate the risk. For example, labels could require the observation of unsprayed buffer zones downwind of the treated area to protect sensitive aquatic or terrestrial environments.

Deterministic vs. probabilistic risk

As the quotient method is deterministic, it can only indicate the possibility of harmful effects, and not their probability or extent. The size of the quotient bears no relation to the ecological significance of any harm that may be caused by exposure to the chemical. Applicants have the opportunity to present further data or argument where they consider that any harm arising from exposure to the chemical will be limited. For example, if exposures are transient and affected organisms have high reproductive capacity, applicants may present data or argument to support a more relaxed approach to mitigation than would result from rigid maintenance of quotients below levels of concern. The overriding consideration is protection of populations and ecosystems, rather than individual organisms.
Chapter 10, Probabilistic Risk Assessment of the RAM provides a discussion and comparison of OECD, US EPA and EU approaches to this emerging tool for conducting environmental risk assessments. Probabilistic risk assessment methods provide more information on the probability and extent of harm associated with the use of a chemical. Such methods provide a more realistic and often less conservative basis for determining the risk, and the nature and extent of any measures that may be necessary to mitigate the risk, but generally need to be supported by a much larger database. This method is used where sufficient data are available. Probabilistic approaches to risk assessment used by applicants will be evaluated on their merits.

Secondary Exposure risk

merging areas of risk assessment are secondary exposure effects, particularly through the terrestrial food chain and its importance in bioaccumulative and persistent pesticides.

5.2 Specific requirements for particular proposals

There are numerous specific use patterns and/or situations, which due to their intrinsic nature, may require additional information. Examples include:

1. Cooling system antifoulants and similar products;
2. Timber preservative treatments;
3. Biotechnology products (see Section 1.1 for further details);
4. Products containing nanomaterial; and
5. Swimming pool products.

While it is not possible to address all of these specific use patterns in this document, an example of a specific use situation (marine antifoulant paints) has been addressed below to demonstrate the additional data elements that may be required.

5.2.1 Marine antifoulant paints

For assessment of a marine antifoulant paint it is essential to have a comprehensive set of fate data relevant to the fate of the active constituent/s in estuarine/marine situations, and of ecotoxicity data relevant to estuarine/marine species. The dossier must also indicate clearly the method of use and types of vessels which are to be treated with the product.

The risk assessment will compare predicted and, if available, measured levels of the active constituent with ecotoxicological endpoints. Marina and harbour situations or other scenarios will be considered, as appropriate for the intended use of the paint.

MAMPEC

Modelling is used to predict concentrations in water and sediment arising from release of the active constituent during the life of the coating. According to the procedures discussed in the OECD Emission Scenario Document for Antifouling Products (OECD, 2005), the MAMPEC model will be used, with OECD default scenarios (van Hattum et al., 2002). Applicants have the opportunity to submit their own modelling using MAMPEC or other models. In the past, simple tidal prism modelling has been used with worst case local Australian scenarios, whether the OECD default scenarios should be adapted to better represent Australian scenarios is under consideration.

Certain information on the physicochemical properties and environmental fate of the active constituent is essential for modelling with MAMPEC, as described in the model and related guidance documents (van Hattum et al., 2002; Baart et al., 2008; http://www.cepe.org/ last accessed April, 2010).

Release Routes

Information is also essential on the release rate of the active constituent from the coating. Generally, the “steady state” release rate is considered, as discussed in OECD (2005). Annex 2 to that document (CEPE Anti-Fouling Working Group, 2003) explains how the release rate may be determined, including the use of ASTM/ISO laboratory methods to measure the release rate, field tests, and the European Paint Industry (CEPE) mass balance calculation method. Applicants must submit available results from such testing with the same or very similar paints, but these results will be compared with calculated results by the CEPE method to determine the most appropriate value for further modelling. Various parameters are needed to use the latter method, and these are often not evident from the product label or associated information.

CEPE Input Data

Applicants must ensure that all the necessary information is available to enable calculation of the release rate, or confirmation of a release rate which has already been calculated. As indicated in Appendix 1 of CEPE Anti-Fouling Working Group (2003), input values for the equations used include:

• the dry film thickness,
• specified lifetime for that dry film thickness,
• weight fraction of active ingredient in the biocide,
• concentration of biocide in the wet paint,
• solid volume ratio (volume of dry paint versus volume of wet paint in %), and
•  the specific gravity of the wet paint.

Monitoring Data

f monitoring data is available, it must be submitted, together with a discussion/risk assessment of levels which have been found in the environment relative to ecotoxicity data.

5.2.2 Emission Scenario Documents

An Emission Scenario Document (ESD) is a document that describes the sources, production processes, pathways and use patterns with the aim of quantifying the emissions (or releases) of a chemical into water, air, soil and/or solid waste. There are a range of “Emission Scenario Documents” prepared by the OECD for various situations which may provide useful guidance to applicants in preparing risk assessments for some agricultural product situations. These documents may be located on, and downloaded from, the OECD web site (last accessed April, 2010).

Many of the ESDs listed on the OECD website pertain more to industrial than agricultural or veterinary chemicals, but those currently available which may be useful for products considered to be agricultural products include:

• Series No. 2: Wood preservatives
• Series No. 4: Water Treatment Chemicals
• Series No. 13: Antifoulants main document and ANNEX (OECD, 2005)
• Series No. 14: Insecticides for Stables and Manure Storage Systems.

The list of ESDs is continually growing, so applicants should check from time to time for updates. OECD scenarios are likely to be “worst case”, and will be adapted as appropriate for local situation.

5.3 Data Protection

As Data Protection is likely to impact the data requirements of a submission, applicants should refer to relevant parts of MORAG to ensure that they possess an understanding of the implications for their application.

6. Format for Submission of Part 7 Environment Data

6.1 OECD format

The APVMA requires that all data submissions be made in accordance with the OECD common format for pesticide registrations as depicted in Figure 6‑1 below. As the OECD states: “Pesticide producers, who are responsible for testing any pesticide they want to register, usually have to present registration submissions in different formats for different OECD countries. The OECD common format should therefore reduce redundancies in the preparation of submissions by industry.”

Figure 6‑1 OECD Plant Protection Products Dossier Structure and Content

Applicants are advised to follow the comprehensive guidance documents and forms located on the OECD website (last accessed April, 2010), when preparing submissions.

7. More Information

Applicants seeking further information regarding environmental data requirements for specific uses should contact the Director of the Chemical Assessment Section, Environment Protection Branch, DSEWPC by email at CASadmin@environment.gov.au

Additionally, applicants have the opportunity to contact the APVMA to request pre-application advice. Refer to 3. Pre-Application advice in “The registration process” (Chapter 3; Volume 1) in MORAG for further details.

8. Glossary

Active constituent

The substance or substances in a formulated product that are primarily responsible for the biological or other effects that make the product an agricultural or veterinary chemical product.

Acute toxicity testing

There is no easily agreed definition for ‘acute’ when used to describe the exposure period in ecotoxicity testing. However, it generally refers to some very short period (e.g. < 10%) in relation to the organism’s typical expected life span. Acute toxicity testing generally has lethal effects as the end-points. For example, an acute Daphnia test would be performed over 48 h, with the end-point being immobilisation (an EC50 would be determined), or a fish test would be performed over 96 h with the end-point being death (an LC50 would be determined).

Agricultural chemical product

A substance or mixture of substances that fits the legal definition in the Agricultural and Veterinary Chemicals Code.

ANZECC

Australian and New Zealand Environment and Conservation Council operated between 1991 and 2001 with the aim of providing a forum for consultation and co-ordination between the State, Territory and Commonwealth governments of Australia and the Government of New Zealand on environmental and conservation issues. See more information about ANZECC and its publications (external site) (last downloaded April, 2010).

Chronic toxicity testing

There is no easily agreed definition for ‘chronic’ when used to describe the exposure period in toxicity testing. However, it generally refers to a substantial period (e.g. >90%) in relation to the organism’s typical expected life span. Chronic toxicity testing normally has sub-lethal effects as the end-point. For example, a chronic Daphnia test would be performed over 21–28 days, with the end-point being reproduction (NOEC and LOEC would be determined for number of young, etc), or an algae test would be performed over 72 h or 96 h with the end-point being growth rate or number of cells (an EC50 and/or NOEC and LOEC would be determined).

Environment Protection and Heritage Council (EPHC)

The objective of the Environment Protection and Heritage Council is to ensure the protection of environment and heritage of Australia and New Zealand. The statutory objects specified in the NEPC Act (Section 3) are:
to ensure people enjoy the benefit of equivalent protection from air, water or soil pollution and from noise, wherever they live in Australia; and
decisions of the business community are not distorted, and markets are not fragmented, by variations between participating jurisdictions in relation to the adoption or implementation of major environment protection measures.

Predicted Environmental Concentration (PEC)

Normally the PEC is derived from set parameters, such as the concentration in water if a still water body (or soil) of 15 cm depth was sprayed at the label rate, unless evidence (use pattern, research etc) indicates otherwise (e.g. the product is incorporated to a depth of 5 cm soil).

Good Product Stewardship

A companies’ initiated program to promote responsible manufacture, use and disposal of the product.

LC50

The concentration of a substance that produces death in 50 per cent of a population of experimental organisms within a specified period. It is usually expressed in milligrams per litre (mg/L) or milligrams per kilogram (mg/kg) as a concentration in food, water or air.

LD50

The dose of a substance that produces death in 50 percent of a population of experimental organisms within a specified period. It is usually expressed in milligrams per kilogram (mg/kg) of body weight.

Lowest-observed-effect concentration (LOEC)

The lowest test concentration in a concentration series which is statistically significantly different from the control value within a specified time period. The measured effect (i.e. endpoint) is normally the result of chronic or sub-chronic testing. The LOEC is most meaningful when stated in relation to the NOEC. If the LOEC is the lowest test concentration of the test concentration series, then it should be stated as ‘LOEC lowest test concentration’.

Safety Data Sheet (SDS)

Previously referred to as Material Safety Data Sheet (MSDS) Safety Data Sheets produced by manufacturers/ importers provide the information needed to allow the safe handling of hazardous substances.

No-observable-effect-concentration (NOEC)

The next lowest concentration in the concentration test series from LOEC. The measured effect (i.e. endpoint) is normally the result of chronic or sub-chronic testing. The NOEC is most meaningful when stated in relation to the LOEC. If the NOEC is the highest test concentration of the test concentration series, then it would be stated as ‘NOEC is = highest test concentration’.

Non-active constituent

Any ingredient other than an active constituent which is part of a formulated product. Non-active constituents are added at the time of manufacture for various reasons, e.g. to improve formulation characteristics such as stability, solubility and spreadability.

Product

A formulation containing one or more active constituent(s), and possibly non-active constituents(s), which is intended for application, with or without dilution prior to use, and which is labelled with directions for use.

RQ

The potential hazard of the chemical to the environment can be determined by dividing the estimated environmental concentration by the relevant toxicity concentration. The resulting risk quotient, RQ, then provides a measure of the risk to the organism concerned.

Risk

The likelihood that a substance will cause harm in the circumstances of its use.

Risk assessment

An evaluation of scientific information on the hazardous properties of substances and the extent of environmental exposure to those substances. The estimate of risk is based on the anticipated level of exposure and the hazard posed by the substance in question. The existence of response variability means that the hazard is not uniform for everyone.

Sub-chronic toxicity testing

The exposure period described between acute and chronic (e.g. 10%<sub-chronic<90%). Sub-chronic testing normally has sub-lethal effects such as reproductive effects (e.g. decreased brood size), growth, or behaviour (e.g. reaction to light) as end-points. For example, a fish early life stage test may have embryos exposed up until the time of hatching and 32 days post-hatching, with number hatched, time to hatching and growth as end-points.

Use-pattern

he combination of all factors involved in the use of a formulated product, including the concentration of active constituent in the preparation being applied, rate of application, method of application, frequency and duration of treatments, additives recommended and other directions which determine total quantity applied, timing of treatment and withholding period.

9. References

ANRA (Australian Natural Resources Atlas; 2001) Australian Agriculture Assessment, National Land and Water Resources Audit, c/o Land & Water Australia on behalf of the Commonwealth of Australia, Appendix 2. ISBN: 0 642 37121 0.

http://www.anra.gov.au/topics/agriculture/pubs/national/agriculture_asris.html (last accessed April 2010).

Australian Pesticides and Veterinary Medicines Authority. Manual of Requirements and Guidelines (MORAG).

Baart A, Boon J and van Hattum B (2008). User Manual – Quick Guide MAMPEC Version 2.0. IVM Report, Deltares/Delft Hydraulics Report. Institute for Environmental Studies, Vrije Universiteit, Amsterdam, The Netherlands. Deltares/Delft Hydraulics, Delft, The Netherlands.

CEPE Anti-Fouling Working Group (2003). Provision of biocide leaching rate data for anti-fouling products. A discussion document from the Anti-Fouling Working Group of CEPE. Internet: http://www.oecd.org/dataoecd/33/37/34707347.pdf (last accessed April 2010).

Environmental Risk Assessment Guidance Manual (RAM) for agricultural and veterinary chemicals may be located on, and down loaded from, the Environment Protection and Heritage Council web site at:
http://www.ephc.gov.au/taxonomy/term/75 (last accessed April 2010).

Fletcher J S, Nellessen J E and Pfleeger T G 1994.‘Literature review and evaluation of the EPA food-chain (Kenaga) nomogram, an instrument for estimating pesticide residues on plants’, Environ. Toxicol. Chem. 13 (9), 1383–91.

Kenaga E E 1973.‘Factors to be considered in the evaluation of the toxicity of pesticides to birds in their environment’, in F Coulston and F Korte (eds), Environmental Quality and Safety: Chemistry, Toxicology, and Technology. Georg Thieme Publishers, Stuttgart, West Germany, pp 166–81.

National Registration Authority for Agricultural and Veterinary Chemicals 1997. Ag Labelling Code: Code of Practice for Labelling Agricultural Chemical Produces, NRA, Canberra, ISBN 0 642 26474 0.

OECD (2005). OECD Environmental Health and Safety Publications. Series on Emission Scenario Documents No. 13. Emission Scenario Document on Antifouling Products (and Annex). Environment Directorate, Organisation for Economic Co-operation and Development. ENV/JM/MONO(2005)8. Internet: http://www.oecd.org/document/46/0,3343,de_2649_34373_2412462_1_1_1_1,00.html (last accessed April 2010).

Pfleeger T G, Fong A, Hayes, R Ratsch H and Wickliff C 1996.‘Field evaluation of the EPA (Kenaga) nomogram, a method of estimating wildlife exposure to pesticide residues on plants’, Environ. Toxicol. Chem. 15 (4), 535–43.

Probst et al. (2005) Scenario-Based Simulation of Run-off-Related Pesticide Entries into Small Streams on a Landscape Level. ScienceDirect - Ecotoxicology and Environmental Safety http://www.sciencedirect.com/science (last accessed April 2010).

Urban D J and Cook N J 1986. Hazard Evaluation Division, Standard Assessment Procedure, Ecological Risk Assessment, EPA 540/9–85–001, US EPA, Washington DC.

an Hattum B, Baart AC and Boon JG (2002). Computer model to generate predicted environmental concentrations (PECs) for antifouling products in the marine environment. 2nd edition accompanying the release of Mam-Pec version 1.4. Report number E-02-04 / Z 3117, Institute for Environmental Studies (IVM), Vrije Universiteit, Amsterdam, The Netherlands. Internet July, 2009: http://dare.ubvu.vu.nl/bitstream/1871/10432/1/f4.pdf (last accessed April 2010).

10. Attachment

1. Worked Example of DSEWPC Run-off Model

1.1 Example 1 (Simple Example)

The following is a straightforward example using publicly available data for the herbicide oxasulfuron. It is assumed that there are no peculiarities in the applications of the herbicide.

Table 2: Physical Parameters for Oxasulfuron (Tomlin 2003)

Parameter	Value
DT50	10 days
Koc	30.6 mL/g.
Water solubility	52 mg/L
Application	200 g ac/ha.
Formulation	N/A
Crop Situation	Soya beans.

*pre-emergent assumed; value approximately doubled for example

Table 3: Simplified Ecotoxicology Data (ibid)

Parameter	Value
LC50 Bluegill Sunfish	116 mg/L
LC50 Daphnia	89.4 mg/L
EC50 Algae Selenastrum capricornutum	0.145 mg/L

Background crop information

The main production areas are West Moreton, eastern Darling Downs, Burnett and the Emerald and St George Irrigation areas in Queensland. In New South Wales Soya beans are grown in the inland irrigation areas from the Murray River Valley in the South to the Macintyre River valley along the Queensland border (Cribb 1991).

Analysis

Run-off is highly dependent on several factors, some of which are location specific and others event specific. The most important are rainfall and its intensity, infiltration of soil (in turn related to moisture content of soil), the slope, type of soil type of drainage, crop type, amount of trash on soil and cultivation (Mensink, et al., 1996). Other influences include mobility and persistence of the pesticide, formulation type and formulation placement (Grover 1989).

In spite of this a reasonable estimation of the amount of chemical in run-off water may be made using a sub-model of the REXTOX model proposed by the OECD (Probst et al., 2005). The model considers rainfall and run-off water, topography of the land (slope), degradation of the pesticide, mobility of the pesticide and buffer zones. In addition to the REXTOX sub-model CAS considers heterogeneity of fields, interception and retention of the pesticide by crops/weeds and sediment transport of the pesticide.

CAS considers the following equation for calculating the percentage run-off:

Equation 1

L%run-off = (R/P) × Crsoil_surface × f1slope × f2bufferzone × f3foliar_application × heterogeneity_factor × 100 + suspended_pesticide.”

CAS conducts a tiered approach to the risk to aquatic species from run-off. Initially the edge of field concentration is calculated considering application specific factors (Tier 1). If risk is shown, pesticide specific factors are taken into account (Tier 2). This is further mitigated by consideration of dilution of the edge of field water in environmental water (Tier 3). Values treated in higher tiers assume a value of 1 until considered.

CAS gives consideration to a rainfall event of 100 mm (P) with 20 mm of run-off water(R) in its worst case scenario (Tier 1) with all factors being considered, excepting Crsoil_surface, which is the subject of the second tier.

Topography, especially slope, is an important consideration in assessing run-off. Soya bean cultivation is not normally conducted on steep terrains. The value adopted for f1slope is 0.5 based on the worst case for applications on slopes ≤ 12.5% (7º) and 1 (no effect) for f2bufferzone, which is the default value (Probst et al 2005). The heterogeneity_factor value is assumed to be 0.5 to reflect the heterogeneity of real fields. This is due to not all parts contributing to run-off. CAS estimates that < 50% of an area effectively contributes to runoff in most realistic circumstances [based on (Dunne & Black 1970)]. For pesticides applied to crops a portion is retained by the crop and not available for run-off during the event. CAS estimates that ½ of the intercepted pesticide is retained based on Linders et al., 2000 citing Willis et al., 1994. The value of f3foliar_application is equal to (1-Fret), where Fret = Fint × 0.5. For weeds and bare soil (as in this case) Fret = 0 and f3foliar_application is consequently = 1. The value of suspended_pesticide = 0 for pesticides with water solubility ≥ 1 mg/L. Pesticides in solution is the major form of transportation, with only chemicals with a water solubility of < 1 mg/L being transported primarily by sediment (Grover 1989); paraquat and diquat being notable exceptions). This is due to the volume of run-off water greatly outweighing the mass of sediment transported in a run-off event (ibid & Afyuni et al 1997).

The solution for the equation is as follows:

Equation 2

L%run-off = (20/100) × 1 (Crsoil_surface) × 0.5 × 1 × 1 × 0.5 × 100 + 0 = 5%.

The concentration of pesticide in the worst case “edge of field” run-off water may be calculated by considering the amount run-off water and amount of pesticide on a hectare basis. On this basis a 20 mm run-off event will result in 200 m3 (200 000 L) of run-off water containing L%run-off × application rate per hectare. The resulting concentration is (5 ÷ 100 × 200 g ac/ha) ÷ 200 m3 = 50 µg/L and the risk to aquatic species is presented in Table 4.

Table 4: Worst Case Scenario EEC and Q (Oxasulfuron)

EEC		0.050 mg/L (50 µg/L)
Most sensitive Species	Toxicity mg/L	Q value
Bluegill sunfish	96 h LC50 = 116	<0.01
Waterflea	48 h EC50 = 89.4	0.01
Algae	EC50 = 0.145 (145 µg/L)	0.34

The scenario shows a mitigable risk to algae and this will be analysed further.

The model is further refined by considering the fate of the pesticide (Crsoil_surface). The model assumes that in a worst case, the run-off event occurs three days after the application of the pesticide. The mobility of pesticide is also taken into account. The fraction of the pesticide available for run-off is related by the equation:

Equation 3

Crsoil_surface = e (-3 ln2 ÷ DTsoil) × (1 ÷ (1 + Kd) for three days of degradation.

CAS uses Kd values if they are available for the specific soil(s) of interest. Otherwise an estimation is used from the formula Kd = Koc × % o.c. ÷ 100. The formula assumes that the only mechanism for adsorption of the pesticide to soil is via the organic carbon content. In most cases this provides a reasonable estimate of Kd. CAS use a default value of 1% o.c. based on available data (ANRA 2001).

Substituting the Koc and DT50 values result in Crsoil_surface = 0.812 × 0.766 = 0.622.

Substituting into Equation results in:

L%run-off = (20/100) × 0.622 × 0.5 × 1 × 1 × 0.5 × 100 + 0 = 3.11%.

The resulting concentration is (3.11 ÷ 100 × 200 g ac/ha) ÷ 200 m3 = 31 µg/L and the risk to aquatic species is presented in Table 5.

Table 5: Scenario Further Mitigated for Fate of Pesticide (Oxasulfuron)

EEC		0.031 mg/L (31 µg/L)
Most sensitive Species	Toxicity mg/L	Q value
Algae	EC50 = 0.145 (145 µg/L)	0.21

The run-off water still shows mitigable risk to algae.

The edge of field concentration of Oxasulfuron shows a mitigable risk to algae.

The effect of the “edge of field” run-off water entering an existing environmental water body is now considered. The following is an adaptation of the USEPA model (USEPA 2004). Consideration is given to a 1500 m3 water body of environmental significance. This could be represented by a 1 ha pond, 15 cm deep or a low flow (~ 0.03 – 0.06 m/sec; ~ 0.1-0.2 km/h) primary stream with 1500 m3 per day flow having approximate dimensions of ~ 2 m wide and ~ 25 cm deep (based on Vietz et al. 2003). In a worst case scenario this water body is considered to be fed entirely by the largest likely field to be 100% treated with the pesticide of interest. The considered field size is 10 ha (USEPA 2004). In most realistic circumstances either the amount of runoff from 10 ha will result in a water body larger than 1500 m3, or to support such a water body a much larger watershed will need to be considered (ibid). This will be considered in a refined model if required. The concentration in the water body may be calculated assuming that 200 m3 of water contaminated with pesticide from each hectare for a total of 10 ha flows into the 1500 m3 water body resulting in a total water body of 3500 m3. The concentration and risk are presented in Table 6.

Table 6: Scenario Mitigated for Environmental Receiving Waters (Oxasulfuron)

EEC		0.017 mg/L (17 µg/L)
Most sensitive Species	Toxicity mg/L	Q value
Algae	EC50 = 0.145 (145 µg/L)	0.12

This shows a mitigable risk but is just above what is considered acceptable. The model has not allowed for further degradation in water or adsorption to sediment in the environmental water. This also represents a worst case hydrologically, which is unlikely to occur in real situations. Accordingly the risk to aquatic species is considered acceptable.

References

Afyuni, et al., (1997).  Run-off of Two Sulfonylurea Herbicides in Relation to Tillage System and Rainfall Intensity.  J, Environ. Qual. (1997) 26:1318-1326.

ANRA (Australian Natural Resources Atlas; 2001) Australian Agriculture Assessment, National Land and Water Resources Audit, c/o Land & Water Australia on behalf of the Commonwealth of Australia, Appendix 2. ISBN: 0 642 37121 0. (http://www.anra.gov.au/topics/agriculture/pubs/national/agriculture_asris.html accessed April 2010)

Birkved & Hauschild (2003) PESTLCI - A Pesticide Distribution Model for LCA. Development of a Pesticide Distribution Model for use in Lifecycle Inventory Analysis. Institute for Product Development. Technical University of Denmark. Lyngby, April 2003.

Cribb J. Ed., (1991) Australian Agriculture, The Complete Reference on the Rural Industry 3rd Ed., National Farmer Federation, Victoria Australia, Morescope Pty Ltd. pp 322. ISBN 0818-4771.

Dunne & Black (1970) Partial Area Contributions to Storm Run-off in a Small New England Watershed, Water Resources Research Vol. 6 No. 5 October.

Grover R. ed., (1989) Environmental Chemistry of Herbicides, Vol. 1, Florida, CRC Press Inc. ISBN 0-8493-4376

Linders et al., (2000) Foliar Interception and Retention Values after Pesticide Application. A Proposal for Standardized Values for Environmental Risk Assessment (Technical Report) Pure Appl. Chem., Vol. 72, No. 11, pp. 2199–2218, IUPAC.

Mensink et al. (1996) How to estimate concentrations of pesticides in surface water semi-quantitatively: an interim report. Report No. RIVM Rapport 679102011, Publisher: Rijksinstituut voor Volksgezondheid en Millieu RIVM, National Institute for Public Health and the Environment, The Netherlands.

Probst et al. (2005) Scenario-Based Simulation of Run-off-Related Pesticide Entries into Small Streams on a Landscape Level. ScienceDirect - Ecotoxicology and Environmental Safety http://www.sciencedirect.com/science (last accessed April 2010).

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Willis et al (1994). Permethrin and Sulprofos Washoff from Cotton Plants as a Function of Time between Application and Initial Rainfall, J. Environ. Qual. 23, 96–100.

11. Revision History

Revision date	Description of revision
January 1997	First Edition
July 2009	Second Edition Complete revision including OECD data requirements and formats.
April 2010	Third Edition Revision after industry comments

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