A Global Review of Methodologies for Aquatic Ecological Risk Assessment

Outline US EPA –Agency-Wide Guidance –Office of Pesticide Programs (FIFRA) –Office of Water (Clean Water Act) EU –Directive 91/414 –FOCUS Recommendations SETAC Involvement

US EPA Agency-Wide Guidance –USEPA (1998). “Guidelines for Ecological Risk Assessment,” EPA/630/R-95/002F, Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC. – sk/guide.pdf.

Office of Pesticide Programs RISK PRESUMPTIONS FOR AQUATIC ANIMALS Risk PresumptionRQLOC Acute High RiskEEC /LC50 or EC Acute Restricted UseEEC/LC50 or EC500.1 Acute Endangered SpeciesEEC/LC50 or EC Chronic RiskEEC/MATC or NOEC1 EEC = Expected Environmental Concentration (ppm or ppb) in water OPP Risk Quotients (RQs) integrate exposure and ecotoxicity data RQs compared to Levels of Concern (LOCs) to indicate potential risk

EECs Generated by exposure models in a tiered process –Tier I: GENEEC - 1 generic site –Tier II: PRZM/EXAMS sites –Tier III: PRZM/EXAMS run for ~ 30 regional standard scenarios (proposed) –Tier IV: Landscape-scale modeling (proposed)

Exposure Scenario Farm Pond Scenario (Tiers I - III) –10-ha field, 1-ha x 2-m pond –Aerial spray drift: 5% or 15% (AgDRIFT) of applied 10 ha 1 ha

GENEEC 1.2 Opening Screen

VERSION 1.3 ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U.S. ENVIRONMENTAL PROTECTION AGENCY TIER ONE SCREENING MODEL FOR AQUATIC PESTICIDE EXPOSURE BETA TEST VERSION PLEASE FAX COMMENTS TO: RON PARKER (703) PLEASE CHOOSE THE LETTER OF THE APPLICATION YOU WISH TO USE: A: ROW CROPS, ORCHARDS, GRASSES AND TURF B: RICE C: CRANBERRIES D: DITCHBANKS AND RIGHTS-OF-WAY ---> GENEEC 1.3 Opening Screen

AgDRIFT Tier I Opening Screen

AgDRIFT Tier I Aquatic Assessment Screen

Limitations of EECs Good for screening out “safe” products Worst case assumptions –Weather, site conditions, edge-of-field drainage, spray drift Scenario does not predict concentrations in flowing systems Landscape factors neglected Partially offset by considering field data

Ecotoxicity Data The ecotoxicity test values (i.e., measurement endpoints) used in the acute and chronic risk quotients derived from the results of required studies Limitations for predicting ecological relevance result from selection of: –Most sensitive species –Lowest reported numbers

Office of Water Clean Water Act –Water Quality Standards Designated uses Water Quality Criteria –Narrative: “No toxics in toxic amounts” –Numeric example: Acute Criterion: take 1/2 the value of pooled acute toxicity values for several genera Response level example: One 1-h excursion above Acute Criterion allowed in 3 y period

Possible New Directions OPP –ECOFRAM work groups Charged with developing more probabilistic methods for risk characterization Office of Water –Proposed rulemaking, Water Quality Standards regulation, criteria excursions Should EPA use kinetic models of organism response or population effects models?

European Union Council Directive 97/57/EC of 22 September 1997 establishing Annex VI to Directive 91/414/EEC concerning the placing of plant protection products on the market Official journal NO. L 265, 27/09/1997 P

Annex VI, Directive 91/ Influence on the environment – Fate and distribution in the environment – Impact on non-target species

Fate and Distribution in the Environment Member States shall evaluate the possibility of the plant protection product reaching surface water under the proposed conditions of use; if this possibility exists they shall estimate, using a suitable calculation model validated at Community level, the short-term and long-term predicted concentration of the active substance and of metabolites [PEC], degradation and reaction products that could be expected in the surface water in the area of envisaged use after use of the plant protection product according to the proposed conditions of use.

Suitable Calculation Models Recommendations of the FOCUS Surface Water Work Group –Tier I/II: “Back-of-envelope” erosion/runoff spreadsheet model for standard scenarios with conservative estimates of drift and drainage –Tier III: Standard scenarios, mechanistic models –Tier IV: Landscape models

Details of FOCUS Tier I/II/III Tiers I/II Back-of-Envelope –Static water body, 30-cm depth –Spray drift: Ganselmeier data, SDTF Tier III Mechanistic –Ten scenarios in 9 countries Ditch, stream, pond –Models: PRZM, MACRO, TOXSWA –Spray drift: same as above, 90th centile

Impact on Non-Target Species Toxicity/exposure ratio for fish and Daphnia –Acute: quotient of acute LC50 or EC50 and the short-term PEC –Chronic: quotient of the NOEC and the long-term PEC Algal growth inhibition/exposure ratio: quotient of the EC50 and the short-term PEC

Limitations of PECs/Quotients Good for screening out “safe” products PECs –Conservative, worst case scenarios do not predict probability of occurrence Quotients –Toxicity values for single species in major taxonomic group limit interpretations of ecological relevance

SETAC Involvement SETAC US –Society of Environmental Toxicology and Chemistry (SETAC) Technical Issue Paper: Ecological Risk Assessment ( What is ecological risk assessment? What is ERA used for? What is..... ? Where is there more information about ERA?

SETAC Involvement SETAC Europe/OECD/EC –HARAP workshop, April 1998 Higher Tier Aquatic Risk Assessment for Pesticides Suggested additional uses of core data, further lab studies, focused field studies Potential for use of probabilistic effects assessment Proposed the concept of an Ecologically Acceptable Concentration (EAC)

Summary Current methods based on single point estimates of exposure and risk Valuable as screening methods Difficult to quantitatively characterize risk if a product fails the screen Initiatives exist to develop more refined methods for risk characterization