Land Application of Sewage Sludges Topics of Current Concern

1. Land Application of Sewage SludgesTopics of Current Concern Ellen Z. Harrison, Director Cornell Waste Management Institute Dept. of Crop and Soil Sciences http://cwmi.css.cornell.edu Cornell Waste Management Institute

2. Topics of Current Concern • Excess nutrients (particularly P) • Human health • Aerosols and odor • Water (wells and runoff) • Direct contact • Food chain (animal products, home garden) • Long term agricultural productivity/Ecohealth • Phytotoxicity (metals) • Soil health (metals, organic chemicals) • Surface water quality • Excess nutrients • Organic chemicals • Metals Cornell Waste Management Institute

3. Health Effects of Land Application "The NRC report issued in July 2002 concluded that, although there is no documented scientific evidence that the 503 regulations have failed to protect public health, further scientific work is needed to reduce persistent uncertainty about the potential for adverse human health effects from exposure to biosolids.” EPA letter, 2004 Cornell Waste Management Institute

4. NRC Findings • Complex mix of toxic chemicals, infectious organisms, and endotoxins may be present • Anecdotal reports of adverse health reactions • No “documented scientific evidence” of failure to protect public health • Lack of exposure and health info on exposed populations Cornell Waste Management Institute

5. Absence of Evidence is not Evidence of Absence Cornell Waste Management Institute

6. Stakeholder Involvement • Called for by NRC • Real contribution to research through local knowledge • Mutual understanding of limitations of research Cornell Waste Management Institute

7. 11/17/04 Cornell Waste Management Institute

8. 11/17/04 Cornell Waste Management Institute

9. Airborne contaminants Odors Irritants Pathogens Endotoxins Toxics Water borne contaminants Pathogens Toxics Nitrates Unevaluated Pathwaysof Concern to Human Health Cornell Waste Management Institute

10. Examples • DeSoto, Florida • Grand Bay, Alabama • Menifee, California Cornell Waste Management Institute

11. WERF Incident Response Effort • Biosolids Summit – July 2003 • Public Partnering Protocol • PSC for Incident Response Investigation Project Cornell Waste Management Institute

12. Organic Chemicals in Sewage Sludges • Many thousand chemicals in use • Few studied • Limits of detection can be insensitive • Lit search obtained data on 516 Cornell Waste Management Institute

13. EPA Soil Screening Levels • Risk-based • Several exposure paths • Trigger for site-specific risk assessment under Superfund • Used by NRC as indicator Cornell Waste Management Institute

14. Cornell Waste Management Institute

15. A=SSL, ingestion and dermal From NRC, 2002 Cornell Waste Management Institute

16. Sludge Application at the Cornell Orchard • 1978: Ley Creek Treatment Plant (Syracuse, NY) sewage sludge, applied at 244 tons/hectare, till depth 20 cm, 0.08 ratio of sludge:soil • 1979 to 1983: test crops grown on plots • 1985: entire site was deep plowed, limed and grass planted • 1986: apple trees planted, ground cover maintained, mowed • 2002: apple trees removed • 1994 and 2001 (16 and 23 years later): soil samples collected and analyzed for PAHs, PCBs and PBDEs (PBDEs, non-detect) by Hale and Laguardia Cornell Waste Management Institute

17. Old Orchard Sludge Plot Cornell Waste Management Institute

18. PAHs - Cornell Orchard (soil), Applied 1978 Laguardia and Hale data Cornell Waste Management Institute

19. PCBs - Cornell Orchard (soil), Applied 1978Laguardia and Hale data Syracuse NY. WWTP, 1972-73, PCBs 6600 ng/g (Furr, et al,1976) Cornell Waste Management Institute

20. PAHs, PCBs are persistent in Cornell Orchard 23 years after application PBDEs below detection limit, consistence with estimated usage rate Conclusion From LaGuardia, et al VIMS Cornell Waste Management Institute

21. Long-term Effects of Sludge Application • One dewatered sludge applied heavily in 1978 • Cumulative metal loading ~EPA 503 limits • Research • Effect on worms – 2003 field and laboratory Cornell Waste Management Institute

22. Orchard Sampling Locations and Extractable Metal Data Cornell Waste Management Institute

23. Looking for Earthworms Cornell Waste Management Institute

24. Number of Worms in the Field Cornell Waste Management Institute

25. Accumulating Organic Matter Cornell Waste Management Institute

26. Reproductive Effectson Worms: Experimental Data Cornell Waste Management Institute

27. Risk assessments contain many assumptions and policy choices Examination of Several Assumptions that Dramatically Impact Calculated Risks to Water Quality Cornell Waste Management Institute

28. Different sludges and sludge products behave differently • Sludge variations • Influents vary • WWTP processes vary • Sludge treatment variations • anaerobic digestion • composting • lime stabilization • heat stabilization/pelletization • alkaline soil amendment Cornell Waste Management Institute

29. What about Class A EQ? • No different than Class B EQ • Endotoxins • Nutrients • Chemicals • Odor potential Note that processing mode impacts fate and transport, odor potential, pathogens Cornell Waste Management Institute

30. Risk assessments contain many assumptions and policy choices Examination of Several Assumptions that Dramatically Impact Calculated Risks • Assessing the Risk to Surface Water • Assessing the Risk to Groundwater • Assessing the Risk of Cadmium to Home Gardener Using Sludge • How much of each crop does the exposed person eat? • How much Cd uptake into the crops? Cornell Waste Management Institute

31. Map of NYS Showing Relative Size of Watershed and Sludge Site Under 503 RA Assumptions Only 0.24% of watershed assumed to receive sludge. A small stream may have much greater %of watershed receiving receiving sewage sludges. What is the risk to person fishing such a stream? What is the environmental risk? Watershed: 427,000 ha Sludged Area: 1074 ha Example Cornell Waste Management Institute

32. Sludges and Water Quality • Movement to Groundwater • In solution • Macropore preferential flow • Enhanced/facilitated transport (movement of contaminant associated with organic matter) Cornell Waste Management Institute

33. Groundwater and 503 RA • Rapid flow phenomena aren’t accounted for in EPA model (macropores) • One test tube experiment with one sludge and one soil are basis for metal mobilities to groundwater in the EPA risk assessment • Substantial dilution or attenuation of leachate before reaching receptor well is assumed (arsenic’s leachate/well concentration ratio is 230) Cornell Waste Management Institute

34. Example:TCLP Leachability of Metals as % total metals Sludge Products Behave Differently Cornell Waste Management Institute Richards, et al 1997

35. Preferential Flow Paths Blue dye reached 6 feet in 1/2 hour Model would predict ~3 years Cornell Waste Management Institute

36. Comparison of Diet Used in EPA Risk Assessment and USDA Recommended Diet How Much Does the Home Gardener Eat? 1+2=USDA Recommended Diet About 2 x as much veg 1=EPA daily diet Used Avg. ~1980 consumption Veg consumption has increased Home gardeners eat high veg diet 1 2 Cornell Waste Management Institute

37. Cadmium Uptake into Leafy Vegetables • 4 orders of magnitude difference (Different crops and cultivars, soils, pH, sludges, etc) • Federal 503 risk assessment used geometric mean • Home gardeners eat from a specific, not avg, garden Cd uptake into leafy veg, data from field studies Cadmium uptake Uptake value used in 503-------- Cornell Waste Management Institute Cadmium Loading

38. Cadmium Calculation for Home Gardener Eating Crops from Sludge-amended Soils Allowable Sludge Cadmium (ppm) 120 EPA calc home gardener risk (not the limiting path) 39 503 limit(soil ingestion path) - - - - - - - - - - - - - - - - - - - 15 simply changing to USDA diet 5 changing to USDA diet and arithmetic mean uptake 1.5 changing to USDA diet and 90th percentile uptake Changing a few assumptions results in very different standard Cornell Waste Management Institute

39. There is no such thing as “Safe” Rather what is the Acceptable Risk? To Whom? Under what conditions? Cornell Waste Management Institute

40. The Case for Caution Because: • Our ability to confidently predict risks from land application is very limited • Contaminants concentrate in sewage sludges • Many unevaluated contaminants in sludges (503 -only indicator pathogens and 9 elements) • Present standards are based on a risk assessment with many short comings • Liability rests largely with the farmer • If problems, hard to prove cause • Enforcement and monitoring are inadequate • Reports of illness Cornell Waste Management Institute

41. Management Considerations Regarding Use of Sewage Sludges and Sludge Products Cornell Waste Management Institute

42. Setbacks • From homes, schools, etc • From wells • From groundwater • From bedrock • From watercourses/floodplains • Significant aquifers Cornell Waste Management Institute

43. Application Practices • Incorporation - if yes, when • Pasture application • Food crops • Stockpiling • Soil type –permeability, steep, karst Cornell Waste Management Institute

44. Legal/Administrative • Indemnification agreement • Record keeping • Testing –frequency and/or parameters beyond 503? • Archive samples • Site specific permits for bulk application Cornell Waste Management Institute

45. Use • Nutrient Mgmt plan • Application rate – P based? • Soil testing • Limit annual application amount • Limit cumulative amount • Limit frequency of application • Limit % of a watershed that can be sludged • Not on frozen ground • Not when soils is within 75% of field moisture capacity Cornell Waste Management Institute