Proposed Rule on Conventional Pesticides (40 CFR Part 158) May 3-4, 2005 Holiday Inn Rosslyn 1900 N. Fort Myer Drive Arlington, VA 22209

Transcription

1 Proposed Rule on Conventional Pesticides (40 CFR Part 158) May 3-4, 2005 Holiday Inn Rosslyn 1900 N. Fort Myer Drive Arlington, VA 22209

2 Environmental Fate and Effects Division Environmental Fate Data Requirements Office of Pesticide Programs U.S. Environmental Protection Agency May 4, 2005

3 Purpose of Fate and Transport Assessments Where and how does the pesticide move in the environment major routes of dissipation. How long will it persist? What degradation products are produced and in what quantities? How much parent and/or degradate is likely to reach ground water and/or surface water? 3

4 Laboratory Studies: Degradation Hydrolysis Photodegradation in Water Photodegradation on Soil Photodegradation in Air 4

5 Laboratory Studies Metabolism Aerobic Soil Metabolism Anaerobic Soil Metabolism Anaerobic Aquatic Metabolism Aerobic Aquatic Metabolism 5

6 Laboratory Studies Mobility and Bioaccumulation Batch Equilibrium Soil Column Leaching Laboratory Volatility Accumulation in Fish 6

7 Field Studies Field Volatility Terrestrial Field Dissipation Aquatic Field Dissipation Forest Field Dissipation Bioaccumulation in Aquatic Non- Target Organisms Prospective Groundwater Monitoring 7

8 Summary l No new tests l Codify current practices l Evolving science, FIFRA, FQPA l Peer review and public participation on significant changes l Clarify test notes l Update required versus conditionally required based on risk assessment experience 8

9 9 Review of Laboratory Fate Studies

10 Hydrolysis Studies [ ] l Purpose: To establish the significance of chemical hydrolysis as a route for degradation of a pesticide and to identify the hydrolytic products formed. l What happens to the pesticide under acidic, neutral, and alkaline environments? l Required (R) for all use patterns except indoor where it is conditionally required (CR) 10

11 What s Changed? l Proposed to be conditionally required (CR) for indoor uses l May be required to support products for indoor uses for which environmental exposure is likely 11 l Longstanding practice

12 PHOTODEGRADATION Aqueous Photolysis ( ) Soil Photolysis ( ) Air Photolysis ( )

13 Purpose of Photodegradation Studies l Potential to degrade in water, soil, or air when exposed to sunlight l Data on the identity, formation, and persistence of photoproducts 13

14 What s Changed? l Photodegradation in Water Proposed new test note Not required when the electronic absorption spectra, measured at phs 5, 7, and 9, of the chemical and its hydrolytic products, if any, show no absorption or tailing between 290 and 800 nm. Longstanding practice 14 l Photodegradation on Soil Proposed R for terrestrial and forestry uses Previously was CR Longstanding practice

15 What s Changed? l Photodegradation in Air Adding conditional requirement for greenhouse, forestry, and residential outdoor uses New test note In view of methodological difficulties with the study, prior consultation with the Agency regarding the protocol is recommended before the test is performed. 15

16 Soil and Aquatic Metabolism Studies Aerobic Soil Metabolism ( ) Anaerobic Soil Metabolism ( ) Anaerobic Aquatic Metabolism ( ) Aerobic Aquatic Metabolism ( ) 16

17 Purpose: To Provide Information On... -Microbial degradation in soil and water systems -Measure rate transformation of parent compound -Provide information on the formation/decline of degradation products 17 -Exposure model inputs

18 What s Changed for Aerobic Soil Metabolism? l Expanded to require for aquatic food and nonfood crop uses for aquatic sites that are intermittently dry l Conditionally required l Presented to the SAP in

19 When is the Anaerobic Soil Metabolism Study Required and What s Changed? l Required (R) for all terrestrial uses l Missing from current CFR due to a printing error 19

20 What s Changed for Anaerobic Aquatic Metabolism? l Proposed required (R) for terrestrial uses l Advances in ecological risk assessment and drinking water assessments 20

21 What s Changed for Aerobic Aquatic Metabolism? l Proposed required (R) for terrestrial and forestry uses l Advances in ecological risk assessment and drinking water assessments 21

22 Mobility Studies Batch Equilibrium ( ) Soil Column Leaching ( ) 22

23 Purpose l Will give an indication of how fast a dissolved compound will move relative to the movement of water l Describes the distribution of pesticide between water and soil at equilibrium l Needed for inputs to exposure models l No changes are proposed 23

24 24 Laboratory Volatility ( )

25 Purpose of the Laboratory Volatility Studies and What s Changed l Determine amount and rate of volatilization under controlled conditions l When Required Conditionally required (CR) for terrestrial and greenhouse uses not required when vapor pressure < 10-6 mmhg l No changes are proposed 25

26 26 Laboratory Studies of Pesticide Accumulation in Fish

27 Purpose of the Accumulation in Fish Study l Determine if pesticide residues accumulate in fish used as human food sources l Determine the extent of pesticides in edible portions of such fish l Data provides information on ecological food chain exposure 27

28 What s Changed? l Clarified test note about conditions for when the study is required 28

29 Integrating Fate Data 29 Building a Conceptual Model

30 The Conceptual Model l Hypothesis developed using assumptions derived from the laboratory data l Since lab studies evaluate specific fate and transport properties individually, they allow for the development of a conceptual model that includes only those processes that are significant. 30

31 The Conceptual Model l Field studies provide the primary mechanism for testing and refining the hypothesis. l Field studies give site-specific information on the fate and transport of a pesticide and its degradates under actual use conditions. 31

32 Field Studies l l l l l Terrestrial Field Dissipation Aquatic (sediment) Dissipation Forestry Dissipation Combination and Tank Mixes Accumulation in Aquatic Nontarget Organisms 32

33 Important l Dissipation in the field is NOT the same as degradation of the pesticide in individual laboratory studies l Dissipation in the field results from interaction of multiple processes at work in the entire soil and/or water system 33

34 Dissipation can result from any one process or combination of the following processes Spray Drift Volatilization Foliar Interception & Dissipation Surface Runoff Lateral Flow Tile Drainage Sorption / Retention Applied Pesticide Leaching Transformations microbial chemical Plant Uptake Washoff 34

35 How Do We Use Field Studies? l Data from field studies can provide more realistic estimates of the persistence and transport of an active ingredient and its degradates l Can reduce potential overestimation of exposure and risk and can confirm assumptions of low levels of toxic degradates l Results can be used to propose scenario-specific effective risk mitigation 35

36 36 Terrestrial Field Dissipation ( )

37 What s Changed? l Expanded conditional requirement to include aquatic sites that are intermittently dry l Merged with the long-term field dissipation study l Added independent laboratory validation of analytical methods 37

38 Aquatic Field Dissipation Studies ( ) l Similar scientific issues as the terrestrial field dissipation study l Required for pesticides with aquatic uses l Conditionally required (CR) for terrestrial uses based on potential for aquatic exposure and if pesticide residues have the potential for persistence, mobility, non-target aquatic toxicity, or bioaccumulation 38

39 What s Changed? l Expanded conditional requirement to include terrestrial uses l Clarified conditions for when study is required 39 l Added independent laboratory validation of analytical methods

40 40 Forestry Dissipation ( )

41 What s Changed? l Changed from required to conditionally required l Added independent laboratory validation of analytical methods 41

42 42 Field Volatility ( )

43 43 Field Accumulation in Aquatic Non-Target Organisms ( )

44 44 Prospective Groundwater Monitoring ( )

45 PGW Study l Generally triggered by drinking water concern (FQPA) l Conditionally required (CR) for terrestrial and forestry uses 45

46 Summary l No new tests l Codify current practices l Evolving science, FIFRA, FQPA l Peer review and public participation on significant changes l Clarify test notes l Update required versus conditionally required based on risk assessment experience 46