1. Pesticides in Nursery Runoff:Sources and Transport Processes Jay Gan Dept. Environmental Sciences UC Riverside, CA 92521 jgan@mail.ucr.edu 909-787-2712

2. Outline • Nursery and pesticides • Current issues • How does it happen? • Governing Processes

3. Nursery in CA(2001) • Production sales: • $3.17 billion • 10.6% of CA agricultural output • 2nd among all CA agricultural products • 21.3% of the U.S. nursery/floriculture total (11.9% for FL) • Retail sales • $10.1 billion • 1st in the U.S. • CA horticulture industry jobs • 81,011 jobs in production • 87,856 jobs in retailing

4. CA Nursery Industry Total CA Nursery/Floral Production: $3.2 billion (2001) Floral 12% Misc. 8% Woody, decidous Evergreen 26% Potted plants Flowering foliage 20% Bedding plants 15% Non- Ornamentals 19%

5. CA Nursery Industry Total CA Retail Sales: $10.1 billion (2001) Florists $988 mil Hardware Home centers $3,576 mil Chain stores Warehouses $2,757 mil Garden centers Farms Nurseries $2,859 mil

6. CA Nursery Industry Total Sales Composition (2001) Lawn furniture Accessories Tree trim 20.8% EquipmentTools 28.4% Chemicals Fertilizers 24.8% Green goods 26.0%

7. CA’s Top 10 Nursery, Flower and Foliage Producing Counties

8. Nurseries & Pesticides • Pesticide Uses • Agricultural crops • Home lawns/gardens • Structural/indoor pest control • Nurseries • Roadside • Parks

9. Pesticide Use in California by Sectors (million lbs)

10. Trend of Pesticide Use Total Active Ingredients (mil lbs)

11. Top Ten in California

12. Use Trend of “Reproductive Toxic” Pesticides in CA

13. Reproductive Toxic Products

14. Use Trend of Carcinogenic Pesticides in CA

15. Carcinogenic Pesticides

16. Use Trend of Cholinesterase Inhibiting Pesticides in CA

17. Cholinesterase-Inhibiting Pesticides

18. Use Trend of Groundwater-Risk Pesticides in CA

19. Groundwater-risk Pesticides

20. Midge Chironomus Mayfly Procloeon Surface water-Risk Pesticides • Not human safety concern ! • Aquatic toxicity: • Organophosphate insecticides (e.g., Dusban, diazinon) • Carbamate insecticides (e.g., carbaryl) • Synthetic pyrethroids (e.g., cyfluthrin, permethrin, …)

21. Most Used Nursery Pesticides (San Diego County, 2002) Greenhouse Containers Source: CDPR

22. Most Used Nursery Pesticides (San Diego County, 2002) Outdoor Containers Source: CDPR

23. Aquatic Toxic Insecticides (San Diego County, 2002) Greenhouse Containers Source: CDPR

24. Aquatic Toxic Insecticides (San Diego County, 2002) Outdoor Containers Source: CDPR

25. Water Quality Issues • Ground water issues • Surface water issues • TMDLs • TMDL examples

26. Groundwater Issues • TheCA Picture (CDPR, CWRCB) • 324 of 3,165 wells in year 2000 • 84 verified detections • From previous use (fumigants) • DBCP, EDB, 1,2-D • From existing use (herbicides): • Simazine, ACET (from simazine or atrazine), DACT, norflurazon, bromacil, diuron, atrazine, deethyl atrazine

27. Distribution of Verified Detections

28. Surface Water Quality Issues • Urban surface water quality issues • Pesticide detections in most streams • 99% streams with 1 pesticide • 70% streams with  5 pesticides • Sustained insecticide levels • Harmful to aquatic organisms • Beneficial use • TMDLs for many streams • The new rule!

29. What is TMDL? • CWA 303(d) • States to make list of “impaired” waters • Develop TMDLs for the listed waters • TMDLs to account for all pollutants and all sources, • TMDL includes non-point sources, e.g., urban and agricultural runoffs • Develop implementation plans (Basin Plans or Water Quality Control Plans in CA)

30. California: • RWQCBs • 800 TMDLs in total • 120 TMDLs in progress • Amend the Basin Plan by incorporating TMDLs • TMDL Elements: • Problem statement • Numeric targets • Source analysis • Allocations • Implementation plan • Linkage analysis • Monitoring/Re-evaluation • Margin of safety

31. High priority TMDLs in CA

32. High priority pesticide TMDLs in CA

33. San Diego Creek Pesticide TMDLs

34. San Diego Creek Pesticide TMDLs • Diazinon: • 200-455 ppt  50 ppt • 300-900% reduction! • Chlorpyrifos: • 87-111 ppt  14 ppt • 600-800% reduction! • Legacy pesticides: • DDT, chlordane,… • Urban use is the No.1 source!

35. Table 1. Proposed Water-Quality Criteria for Diazinon and Chlorpyrifos

37. How Does It Happen? • Storm water runoff • Irrigation runoff • Leaching through containers? • Planting media spills? • Runoff + planting media = pesticide runoff?

38. Irrigation

39. Nursery Runoff Runoff!

40. Runoff Driven: Storm runoff  Over-irrigation

41. Planting Media

42. Step 1: Scrap off surface soil Step 2: Estimate potting mix content Step 3: Analyze pesticides Step 4: Correlation

44. Pesticides in Spilled Potting Mix

45. Loose Potting Mix

46. Governing Processes • Degradation • Chemical • Microbial • Adsorption • Leaching Potential • Runoff Potential

47. Transport after application

48. Degradation in Soil • What is “degradation”? • Structural changes caused by chemical and/or microbial reactions • Desirable environmentally • Pesticide-dependent • Vary in different soil types • Measured by persistence or “half-life” T1/2 • Long “half-life” = problems • T1/2 = leaching potential  • T1/2  = runoff potential 

49. Pesticide degradation in soil T1/2

50. What Causes Degradation? • Chemical reactions • Hydrolysis (OPs, carbamates, etc.) – pH sensitive • Photolysis – by UV, near the surface • Oxidation – reduction by soil chemical species • Nucleophilic attacks by soil nucleophiles • Pesticide dependent • Soil dependent