Kit de Herramientas para el Registro de Plaguicidas

Introduction

The general protection goal for aquatic species is to protect biodiversity and ecosystems. The focus is on protecting aquatic species at the population level although the acute risk assessment for aquatic vertebrates may also seek to protect individuals.

The major routes of exposure of aquatic species to a pesticide are from spray drift or run- off from the treated area. The scope of the environmental assessment will depend on the potential groups of non-target species that could be exposed and that could be at risk.

The acute and chronic risks to aquatic species are generally assessed using a tiered approach. An initial (screening) level risk assessment assumes a worst-case scenario and identifies those pesticides and associated uses that do not pose a risk to aquatic species. When acceptable risk cannot be determined at the initial (screening ) level then more refined higher tier risk assessments are undertaken and/or risk mitigation measures applied.

What this page contains

This table summarises the principles applied during the risk assessment to determine whether the environmental risks in relation to surface water and aquatic species (fish and shrimp) are acceptable. The focus is on the screening level assessment. The screening level assessment identifies those pesticides and uses where no further testing or analysis is required. Where available, links to documents that describe the more complex higher tier assessment in more detail are provided.

Summary analysis

The reader needs to be aware that a key issue for environmental risk assessment in relation to surface water and aquatic species is the limitations inherent in extrapolation from a limited number of test species to a comparatively large number of potential species at risk. Some regulatory frameworks more precisely describe the setting of specific protection goals for water organism (generally at the population level for different organism groups and including at the individual level for aquatic vertebrates), while others rely on the problem formulation component of the risk assessment to identify the specific protection goal and suitable indicator species.

 

 

Australia

Aspect

Description

Links to risk assessment guidelines, manuals and science policy documents

Hazard assessment and end-point selection

The following end-points are derived from the hazard assessment:

  • Fish
    • for acute toxicity the relevant LC50
    • for chronic toxicity the relevant NOEC
  • Invertebrates
    • for acute toxicity the relevant LC50
    • for chronic toxicity the relevant NOEC

Setting of toxicological reference values and the use of assessment factors

The RAC is calculated for acute and chronic exposure scenarios using the following assessment factors:

  • Fish
    • for the LC50 (acute toxicity ) an assessment factor of 10 is applied
    • for the NOEC (chronic toxicity) an assessment factor of 1 is applied
  • Invertebrates
    • for the LC50 (acute toxicity ) an assessment factor of 10 is applied
    • for the NOEC (chronic toxicity) an assessment factor of 1 is applied

Exposure assessment

The exposure assessment involves the calculation of the PEC. The screening level assessment assumes the worst-case scenario of a direct overspray of a shallow aquatic habitat (15cm water depth).
For pesticides used multiple times in one season, the (cumulative) PEC is calculated assuming non-target species are exposed to the peak concentration immediately after the last application. The number of applications, half-life of the active ingredient and time between applications are also considered.
Higher tier run off and spray drift exposure assessments are conducted when acceptable risks cannot be determined at the screening level.

Methodology for higher tier runoff assessment is described in more detail in
https://apvma.gov.au/sites/default/files/publication/15701-runoff-nethod-apvma-publication-template-version-21-july-2015_1.pdf

Assessment of spray drift risks is described in more detail in
https://apvma.gov.au/sites/default/files/publication/51826-spray_drift_risk_assessment_manual.pdf

Risk assessment and acceptability criteria

The risk assessment compares the PEC to the RAC to arrive at a risk quotient.

RQ= PEC/RAC

Risks are considered to be acceptable where the RQ<=1.

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Canada

Aspect

Description

Links to risk assessment guidelines, manuals and science policy documents

Hazard assessment and end-point selection

The following end-points are derived from the hazard assessment:

  • Fish
    • for acute toxicity the relevant LC50
    • for chronic toxicity and early life-cycled test the relevant NOEC
    • for fish life-cycle test the relevant NOEC
  • Invertebrates
    • for acute toxicity the relevant LC50/EC50
    • for chronic toxicity the relevant NOEC

Setting of toxicological reference values and the use of assessment factors

The RAC is calculated for acute and chronic exposure scenarios using the following assessment factors:

  • Fish
    • for the LC50 (acute toxicity ) an assessment factor of 10 is applied
    • for the NOEC (chronic toxicity, including early life cycle and fish life cycle) an assessment factor of 1 is applied
  • Invertebrates
    • for the LC50 (acute toxicity ) an assessment factor of 2 is applied
    • for the NOEC (chronic toxicity) an assessment factor of 1 is applied

Exposure assessment

The exposure assessment involves the calculation of the EEC in an appropriate water body scenario.
The screening level assessment assumes the worst-case scenario of a direct overspray of an aquatic habitat. The EEC is based on direct overspray of an 80 cm water body depth for all aquatic organisms, with the exception of amphibians, which is based on a 15 cm water body depth.

For pesticides used multiple times in one season, the (cumulative) EEC is calculated assuming non-target species are exposed to the concentration immediately after the last application. The number of applications, half-life of the active ingredient, and time between applications are considered when determining the cumulative EEC.
Higher tier run off and spray drift risk assessments are conducted when acceptable levels cannot be determined at the screening level.

Further detail on higher level assessment EECs from surface runoff and on characterising spray drift are provided in PMRA internal guidance document: Environmental Assessment Technical Guidance: Characterization of Risk to Aquatic Organisms, November 2006
The Pesticide Water Calculator is used to calculate the EEC for surface runoff. In using the Pesticide Water Calculator, Canadian scenarios are used to represent various regions in Canada, taking into consideration regional soil characteristics and weather

Further information on the Pesticides Water Calculator can be found at the following US EPA link:
Models for Pesticide Risk Assessment
https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks/models-pesticide-risk-assessment

Risk assessment and acceptability criteria

RQs are calculated using the ratio of the EEC and the RAC.

RQ=EEC/RAC

Risks are considered to be acceptable if the RQ <=1

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China

Aspect

Description

Links to risk assessment guidelines, manuals and science policy documents

Hazard assessment and end-point selection

  • In Tier 1 assessment, a geomean approach is used to select the endpoint.

Higher tier assessments include Species Sensitivity Distribution (SSD) analysis and mesocosm studies. 

Setting of toxicological reference values and the use of assessment factors

  • The Predicted No Effect Concentration (PNEC) based on endpoints and a uncertainty factor is calculated.

In Tier 1 assessment, for fish and daphnia acute study, the uncertainty factor is 100; for fish and daphnia chronic study and algae study, the uncertainty factor is 10. 

Exposure assessment

  • The TOP-RICE model  is used to calculate the PECsw for paddy field.

China-PSEM model will be used to calculate the PECsw for dry land crop, this model is under development.

Risk assessment and acceptability criteria

  • Acceptability criterion is based on the calculation of a risk quotient where RQ=PECsw/PNEC
  • If RQ<= 1, the risk is considered acceptable
  • If RQ>1 the risk is considered not acceptable

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EU

Aspect

Description

Links to risk assessment guidelines, manuals and science policy documents

Hazard assessment and end-point selection

The following end-points are derived from the hazard assessment:

  • Fish
    • for acute toxicity the relevant LC50
    • for chronic toxicity early life stage test the relevant EC10 (NOEC)
    • for full life cycle tests the relevant EC10 (NOEC)
  • Invertebrates
    • for acute toxicity the relevant EC50
    • for chronic toxicity the relevant EC10 (NOEC)

Detailed guidance on tiered acute and chronic effect assessment schemes for aquatic organisms is provided at
https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2013.3290

Setting of toxicological reference values and the use of assessment factors

The RAC is calculated for acute and chronic exposure scenarios using the following assessment factors:

  • Fish
    • for the LC50 (acute toxicity) an assessment factor of 100 is applied
    • for the EC10 or NOEC(chronic toxicity early life stage test) an assessment factor of 10 is applied
    • for the EC10or NOEC (full life cycle tests) an assessment factor of 10 is applied
  • Invertebrates
    • for the EC50 (acute toxicity) an assessment factor of 100 is applied
    • for the EC10or NOEC (chronic toxicity) an assessment factor of 100 is applied

Exposure assessment

The exposure assessment for the aquatic environment is based on the FOrum for Co-ordination of pesticide fate models and their USe  (FOCUS) methodology.

The FOCUS simulation models and scenarios are used to calculate the concentrations of pesticides (PEC) in surface water.

Risk assessment and acceptability criteria

The risk assessment compares the PEC to the RAC. Where the PEC is less than or equal to the RAC the the risks are considered to be low.

In accordance with Commission Regulation (EU) 546/2011 no authorisation can be granted if the active substance and significant metabolites and breakdown or reaction products in surface water:

  • exceed limits for drinking water quality set out in Directive 2000/60/EC (if the surface water is intended for the abstraction of drinking water), or has an unacceptable impact on non-target species, including animals

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USA

Aspect

Description

Links to risk assessment guidelines, manuals and science policy documents

Hazard assessment and end-point selection

The assessment of the ecotoxicological and other relevant data in line with the matters to be taken into account as set out in legislation, forms the basis for the hazard assessment

Abbreviations:
EC10 - concentration that induces an effect to 10% of the test population
EC50 - concentration that induces an effect to 50% of the test population
LC50 - concentration that is lethal to 50% of the test population
NOEC - No Observable Effect Concentration

Setting of toxicological reference values and the use of assessment factors

n.a.

Exposure assessment

The exposure assessment involves the calculation of the EEC. The screening level assessment assumes the worst-case scenario for a water body adjacent to the treated field and highly vulnerable to runoff or leaching.

The generic (non-site specific) model GENEEC2 (GENeric Estimated Environment Concentration) is used for the screening-level risk assessment.

When acceptable risks cannot be determined at the screening-level, higher tiered screening models (PRZM-3 and EXAMS II) that better reflect actual use site conditions are used.

Details on the screening-level exposure assessment, including assumptions are provided in
https://www.epa.gov/sites/production/files/2014-11/documents/ecorisk-overview.pdf

Details of higher-tier exposure assessments, including input parameters is provided in
https://www.epa.gov/sites/production/files/2014-11/documents/ecorisk-overview.pdf

Risk assessment and acceptability criteria

The risk assessment compares the EEC to the acute and chronic toxicity values to calculate the RQ.

RQ=EEC/toxicity value


The LOCs are:

  • where the acute RQ> 0.5, the potential for acute risk may warrant a regulatory action in addition to restricted use classification
  • where the acute RQ>0.1 for aquatic animals, the potential for acute risk may be mitigated through restricted use classification
  • the potential for endangered species to be affected by use is indicated by an acute RQ > 0.05
  • where chronic RQ>1, the potential for chronic risk may warrant regulatory action or endangered species may potentially be affected through chronic exposure 

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Can the legislative criteria be applied in other countries?

The principles and policies followed in the hazard assessment and end-point selection for surface water and aquatic species is similar across regulatory frameworks and can be applied in any country.

The setting of toxicological reference values for fish and invertebrates is similar across regulatory frameworks, however different regulatory frameworks use different assessment factors when setting the toxicological reference values. Country or regional policy should determine which assessment factors should be applied in setting toxicological reference values depending on the specific protection goal to be achieved.

The exposure assessment involves estimating concentrations of the pesticide in surface water based on a water body scenario. Different regulatory frameworks use different scenarios which will impact the outcome of the assessment. Water body scenarios must be relevant to the country/agricultural area where the pesticide is to be used.

Screening-level/worst case exposure assessments used by some countries/regions may be applicable to other countries. It is important that the regulator understands the scope and limitations of models they intend to use. In many case the risk assessment methods and models used are generally are based on local cropping situations, ecosystems, soil characteristics and weather, particularly for higher tier risk assessments. Country/region specific models based on site-specific, local cropping situations, ecosystems, soil characteristics and weather may not readily be applied in other countries.

The risk assessment approach and acceptability criteria based on comparing the estimated environmental exposure to the toxicological reference value are similar across regulatory frameworks and can be applied in other countries. Some countries apply trigger values (levels of concern) that focus on specific protection goals and/or endangered species. Country or regional policy should determine whether and what trigger values/level of concern should be applied.