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Emerging Pollutants in Biosolids

Emerging Pollutants in Biosolids. Paul Chrostowski, Ph.D.,QEP AMSA Summer Conference July 16, 2003. 1993: 503 Rule Round 1. Started with 200 pollutants Narrowed to 50 for detailed profile assessments

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Emerging Pollutants in Biosolids

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  1. Emerging Pollutants in Biosolids Paul Chrostowski, Ph.D.,QEP AMSA Summer Conference July 16, 2003

  2. 1993: 503 Rule Round 1 • Started with 200 pollutants • Narrowed to 50 for detailed profile assessments • Risk screening identified 22 pollutants for detailed analysis for land app; 16 surface disp; 14 incin. • List modified using non-risk factors

  3. 2003: 503 Rule Round 2 • 411 pollutants from 1988 NSSS • Eliminated detection frequency <1%, no tox, non-specific; aggregated classes. • 31 subject to comprehensive hazard identification study • Resulted in dioxins, co-planar PCBs proposed for regulation.

  4. EPA Reports About 700 Chemicals in Biosolids • 4% regulated or being regulated • 8% PAHs • 20% Brominated aromatics • 8% Pesticides • 14% PPCP • 3% Natural or metabolites • 13% Inorganics

  5. Most Concern is with PPCPs • Problem recognized in 1976 with clofibric acid • Prescription and OTC pharmaceuticals • Diagnostic materials • Personal care products • Preservatives • Disinfectants • Sunscreens • Nutraceuticals

  6. PPCP Dimensions (Adapted from Daughton 2001) • New chemical classes (angiogenesis inhibitors) • Type of use (Viagra) • Type of effect (endocrine disruptors) • Source/matrix (multimodal drugs) • New exposure route (ingestion of musk from fish)

  7. Nothing is as Toxic as Dioxin • Dioxin (TCDD) is thousands of times more toxic than the chemicals currently found in sludge/biosolids • It is highly unlikely that a more toxic chemical will ever be found in biosolids • Regulating for dioxin will ensure help safety for all chemicals.

  8. NAS Biosolids Report and EPA Response • NAS: Comprehensive survey of pollutants in biosolids • EPA: Targeted approach for pollutant survey • NAS: Use improved risk assessments for standard setting • EPA: Focus on key pollutants and pathways with greatest impact

  9. How to Deal with New Chemicals • Focus surveys (Stevens et al. 2003 ES&T 37:462-467) • Partition coefficient, biodegradability screens • Replicate results • Take field measurements • Perform focused risk assessments • Evaluate environmental fate

  10. PBDEs • Widely used flame retardants • Refractory to 2º treatment, persistent • Generally low mobility, toxicity • Focused multiple pathway risk assessment shows concentrations in biosolids below levels of concern for children or adults

  11. Triclosan • Multimodal anti-microbial • Toothpaste, footwear, hand soap, acne creams, Microban® • At least 34 years of safe use as consumer product • Half-life is about 30 days in either aerobic or anaerobic sludge

  12. Alkylphenols • Degradation products of detergent components • Potentially endocrine disrupting • Stable in sludge • Rapidly degrades in land-applied biosolids (t½ = 3-30 days, complete disappearance in 90 days)

  13. Conclusions • Combination of extraordinary advances in analytical chemistry and greater societal reliance on chemicals. • Land applied biosolids as potent biological reactor. • Vigilance, not alarm. Holistic approach, replication, focused risk assessment.

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