EFSA published this guidance document on 5th August 20131. Key issues discussed in the new guidance document are summarised below.
• Move from NOEC to ECX values (EC10 and EC20). • C alculation of acute and chronic RAC values in surface water (RACSW;AC and RACSW;CH) instead of TER values.
• The document considers organisms living in the water column. Separate guidance for the risk assessment to sediment dwelling organisms is expected in the near future.
•H igher tier assessment options (e.g. SSD, geomean, trigger values) are now formalised into a single document. • Tiered aquatic risk assessment process: Tier 1: Standard acute and chronic single species tests Tier 2A: Geomean-AF2 approach where additional single species toxicity tests can enable a geomean L(E)C50 or NOEC/EC10 value to be calculated for species belonging to the same taxonomic group Tier 2B: Species Sensitivity Distribution (SSD) approach can be performed on the additional single species test data to produce a lower limit HC5 (LLHC5) Tier 2C: Refined exposure laboratory test-AF approach using data with modified exposure regimes Tier 3: RACSW derivation on the basis of microcosm/mesocosm tests that consider both the Ecological Threshold Option (ETO), which allows negligible population effects only and the Ecological Recovery Option (ERO), which allows some population level effects if ecological recovery takes place within an acceptable time period
• Assessment of the risk from secondary poisoning for birds and mammals eating fish from contaminated water is required. A RAC for secondary poisoning (RACSP) is calculated and compared with the 21-day TWA PECSW.
• A n assessment scheme for the risk assessment of metabolites and degradation products is presented.
• Mixture risk assessment scheme - guidance on the risk assessment of formulations containing mixtures of active substances is provided. Toxic units (TU) define the ratio between the concentration of a mixture component and its toxicological endpoint. A model deviation ratio (MDR) can be used to determine if the active substances in the mixture act as expected by the concentration addition prediction, act synergistically or act antagonistically.
1. http://www.efsa.europa.eu/en/efsajournal/pub/3290.htm 2. AF: Assessment Factor
Aquatic Risk Assessment
Guidance on tiered risk assessment for plant protection products for aquatic organisms in edge-of-field surface waters
Effects studies and study monitoring
• Data gap analysis to identify critical studies. • Extensive experience of study design, monitoring and evaluation of both laboratory and field studies. Exposure modelling
• Skilled in the application of all surface water exposure models at EU and national level, including FOCUS (STEPS 1-4), EVA/EXPOSIT, Rautmann, TOXSWA-NL, etc.
• Exposure models can be refined for difficult compounds and for novel application methods. Risk assessment
• Tier I and higher-tier risk assessments for all aquatic organism groups. • Development of a range of higher-tier refinements, including:
• Re-evaluation of existing data
• Refinement of exposure models to reduce PECsw concentrations
• Design and interpretation of higher-tier studies, including single and multi-species systems
• Reasoned arguments based on client data and detailed knowledge of public literature
• Up to date knowledge of developments in aquatic risk assessment, including the proposed EFSA guidance document for aquatic risk assessment (published 5th August 2013)
Complete service The APC environment team can offer a complete aquatic risk assessment service, including data gap analysis, preliminary risk assessment, placing and monitoring studies, performing risk assessments and writing the dossier sections. We are also happy to assist in these individual services. Using these approaches, APC have achieved many successful authorisations for the majority of EU MSs.
For more information on any of the above, please contact us on +44 (0) 1937 587962 or email
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Aquatic Risk Assessment
The environmental team at APC has extensive experience of performing aquatic risk assessments under SANCO/3268/2001 for a large range of crops and active substances. We are able to offer advice and assistance at every stage of the aquatic risk assessment:
