Revised Cumulative Risk Assessment: Organophosphorus Pesticides

Revised Cumulative Risk Assessment: Organophosphorus Pesticides Office of Pesticide Programs June 18, 2002

Welcome Lois Rossi, Director Special Review and Reregistration Division

Managing Risk From Organophosphorus Pesticides

Outline of Presentation • Plan for the OPs • Progress to date • Achievements in: • Risk reduction • Methods development • Process improvements

Plan for the OPs • Several OP Reregistration Eligibility Decisions completed before August 1996 • After August 1996 OPs became a major focus of Reregistration and Tolerance Reassessment • In the last six years a tremendous amount of resources dedicated to: • Risk assessment and risk management of the individual OP chemicals • Developing cumulative risk assessment methods and applying them to the OPs • It is appropriate to examine the results and the achievements of the last six years

Implementation of the Plan • Refine available exposure methods and data • Develop a public process to allow greater stakeholder access to information and to facilitate input on: • Science policies • Exposure data and assumptions • Risk assessments • Risk management • Develop methods for aggregate risk assessment • Develop methods for cumulative risk assessment

Status of OPs • 49 total OPs ever registered • 7 cancelled before 1996 • Chlorfenvinphos, Chlorthiophos, Dialifor, Dioxathion, Monocrotophos, Phosphamidon, Sulprofos • 42 started the public participation process

Status of OPs (continued) • 3 early voluntary cancellations • Fonofos, Isazophos, Isofenphos • 5 recent cancellations • Chlorpyrifos methyl, Ethion, Ethyl parathion, Fenamiphos, Sulfotepp • 34 OPs remain

Status of Tolerance Reassessment FQPA: Must reassess all tolerances by Aug. 2006 • 33% by August 3, 1999 • Completed! • Goal 3208, 3290 actually reassessed • 66% by August 3, 2002 • On track for completing goal of 6416 • 100% by August 3, 2006 • Final goal: 9721

Status of OP Tolerance Reassessment • 1691 at the start of FQPA (1996) • 17.4% of all tolerances (9721) • 871 reassessed through revocation or other process • 98 reassessment underway (revocation) • 722 OP tolerances remain to be reassessed

Public Participation Process • Phase 1 -- Registrant "Error Only" Review (30 days) • Phase 2 -- EPA Considers Registrants Comments (up to 30 days) • Phase 3 -- Public Comment on Prel. Risk Asmt. (60 days) • Phase 4 -- EPA Revises Risk Assessments; Technical Briefing (up to 90 days) • Phase 5 -- EPA Solicits Risk Mgmt. Ideas (60 days) • Phase 6 -- EPA Develops Risk Mgmt. Strategies (60 days)

Public Participation Process Individual Reregistration Eligibility Decisions (IREDs) • 39 preliminary risk assessments -- public comment • 39 revised risk assessments B public comment • 32 IREDs/TREDS • Communication about each OP: overviews, summaries, fact sheets, comment responses • Conference calls and closure calls • 18 Technical Briefings • Stakeholder meetings B 3 outside DC

Public Participation Process (continued) TRAC & CARAT (Advisory Committees) • 10 TRAC and 3 CARAT meetings • Numerous TRAC and CARAT Workgroup meetings • 50+ TRAC/CARAT staff papers

Public Participation Process (continued) Development of Cumulative Assessment • 5 Technical Briefings • Drinking Water Methodology Workshop • Numerous Science Advisory Panel meetings • Preliminary assessment B public comment • The release of the revised assessment

Achievements in Risk Reduction - Residential - • Residential use reduced by >20 million pounds annually • Principally as the result of risk mitigation for chlorpyrifos and diazinon

Residential (continued) Universe of chemicals • Started with 17 OPs with residential/public area uses • 7 OPs excluded from cumulative assessment because residential uses were eliminated/reduced to a negligible level (e.g. limited to bait stations, fire ant mounds) • Of the remaining 10, two are limited to public health uses (naled, fenthion) • 3 OPs with residential/public area uses still under review (DDVP, malathion, tetrachlorvinphos)

Residential (continued) Indoor Uses • Initially 9 OPs had indoor uses • Now only DDVP • Initially 6 OPs had pet uses – now only tetrachlorvinphos and DDVP • Indoor use of chlorpyrifos, fenitrothion, and trichlorfon limited to pre-packaged child-resistant bait stations (negligible exposure)

Residential (continued) Protecting Public Health Uses • Public Health uses retained where individual assessments indicate no risks of concern • Chlorpyrifos fire ant mound treatment • Chlorpyrifos mosquito control • Fenthion mosquito control • Naled mosquito and black fly control • Phosmet fire ant mound treatment

Residential (continued) • For the cumulative assessment: • Used daily residential estimates in probabilistic assessment for the first time • developed regional assessments to cover spatial variation throughout the U.S. • These advances together will likely have a major impact on future residential risk assessment methodology

Achievements in Risk Reduction- Food - • Many chemicals faced a much higher standard as the result of the FQPA safety factor requirement • This together with generally very low toxicological endpoints for cholinesterase inhibition resulted in extremely low allowable exposures for most chemicals • EPA & USDA increased PDP monitoring of OP residues on foods highly consumed by children • Agency quickly implemented use of probabilistic dietary exposure estimates on a routine basis

Food (continued) • Most OPs met these very high standards • When dietary risks of concern were identified, risks were mitigated: • Use removed from OP/crop combination • Use pattern changes • e.g., rate, frequency, timing

Food (continued) • Used rigorous methods and high quality data and worked with stakeholders on viable use pattern changes: • Addressed dietary risks of concern • Limited disruption to agriculture

Achievements in Risk Reduction- Drinking Water - • OPP now routinely addressing drinking water risks • Surface water models enhanced to include a scenario representative of a drinking water reservoir • Screening level model developed for groundwater • Agency moved on several fronts to obtain improved water monitoring data and is continuing that work • Effects of drinking water treatment beginning to be addressed

Drinking Water (continued) • OPs are not a major concern for drinking water (relative to some other classes of chemicals) • Time generally allowed for data development when concerns were identified • Drinking water risks were mitigated through: • Use removed from certain OP/crop combinations • Use pattern changes • e.g., rate, frequency, timing, use area

Drinking Water (continued) • For the cumulative assessment: • Used daily drinking water estimates in probabilistic assessment for the first time • Developed regional assessments to cover spatial variation throughout the U.S. • These advances together with improved modeling and monitoring likely to have a major impact on future drinking water risk assessment methodology

Achievements in Risk Reduction- Worker Risk - • Worker risks are important concern for Ops • Very low toxicological endpoints for cholinesterase inhibition often resulted in very low exposures presenting risks of concern • Risk/Benefit balancing required an enormous amount of input from stakeholders

Worker Risk (continued) Agency worked quickly to complete review of ARTF data • Excellent source of extensive, up-to-date data on exposure of re-entry workers • Allowed exposures for specific tasks to be calculated separately PR notice AWorker Risk Mitigation for Organophosphate Pesticides@ • Focused stakeholder attention on worker risks • Leveled playing field by stating EPA’s approach

Worker Risk (continued) • Most chemicals showed some worker risks of concern (handler and/or re-entry) • Two chemicals cancelled in large part due to worker risk: • Mevinphos (1994) • Ethyl parathion (last use date 10/31/03)

Worker Risk (continued) Handler risks addressed in several ways: • Closed mixing loading systems applied to many chemicals/scenarios • Closed cabs with various levels of respiratory protection applied to many chemicals/scenarios • Maximum PPE used in some cases where closed systems not feasible

Worker Risk (continued) • Most hand held application methods eliminated • Certain formulation types (e.g. dusts) eliminated or restricted • Reductions in amount handled • Reduced rates/frequency of application • Some restrictions on amounts used when mixer/loader/applicator is same person • Some restrictions on aerial applications

Worker Risk (continued) Re-entry risks addressed in several ways: • Tailored to specific problem • Significant input from stakeholders • Creative solutions in toughest cases (high risks, high benefits), collecting bio-monitoring and will reexamine risks

Achievements in Risk Reduction- Ecological Risk - Many risk management actions described above also address ecological risks • Chlorpyrifos and diazinon mitigation • Azinphos methyl: eliminated use on sugarcane and cotton in large part due to aquatic concerns • Decreased rates/application frequency; limited area covered (e.g. on golf courses, change from broadcast to spot treatments)

Ecological Risks (continued) Other risk mitigation methods utilized: • Watering in/incorporation of granules • Altered timing of applications to reduce exposure to wildlife at most vulnerable times (e.g. nesting) • Developed new disposal methods for cattle dip vats (coumaphos) • Buffer zones (for spray drift) • Addressed special risk concerns (e.g. honey bees) • Addressed special habitat concerns (fenthion) • Improved labeling (e.g. emphasize best management practices)

Summary • Major accomplishment in which many people played an important role • Better results when people work together • Establishment of an effective public participation process ensures the continuation of a productive working relationship

Science Assessment Staff from the Health Effects Division and Environmental Fate and Effects Division

General Overview and Introduction Randolph Perfetti, Ph.D Associate Director, Health Effects

Roadmap • Background • Activities Since the Preliminary Assessment • Major Revisions in This Assessment • Highlights of Sensitivity Analyses

Background • FQPA 1996 requirements • Methods development • SAP reviews and public comments, technical briefings • Development of Preliminary Assessment • Revised Assessment

What is this Cumulative Assessment • Multiple chemicals with common mechanism of toxicity • Multiple routes of exposure • Multiple pathways of exposure

Activities Since Preliminary Assessment • Addressed the FQPA Safety Factor • Incorporation of new food processing factors • Sensitivity analyses • SAP review • Public comments and technical briefing

Major Differences • Hazard/ Dose Response • Relative Potency Factors • FQPA Factors • Food Exposure • New processing factors • Over- tolerance residues • Time frames • Populations Considered

Major Differences • Water • Number of regions • Populations considered in Region A • Residential • Number of regions • Distributions used • Populations considered in Region A • Pet uses

Major Differences • Regional • Preliminary OP CRA – 13 regions • Revised OP CRA – 7 regions • 7 regions effectively describes geographical/climatological differences

Preliminary Regional Framework Source: USDA ERS

Revised Regional Framework Region A

Regional Integrated Output

Risk Characterization • Summarizes and integrates all of the information from the various components of the assessment. • Looks at: • Strengths and weaknesses of the data used including any potential biases in input parameters and the direction of that bias, • Reliability and availability of the data, as well as the characteristics of the exposure models, and attempts to bound that uncertainty. • The revised assessment discusses in great detail what data have been used; how the data have been used; and the strengths and weaknesses of the resulting analysis.

Revised Cumulative Risk Assessment: Organophosphorus Pesticides