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Secondary Routes of Exposure to Biocides

Secondary Routes of Exposure to Biocides. Rolf Halden, PhD, PE Johns Hopkins University Center for Water and Health Bloomberg School of Public Health Baltimore, MD

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Secondary Routes of Exposure to Biocides

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  1. Secondary Routes of Exposureto Biocides Rolf Halden, PhD, PE Johns Hopkins University Center for Water and Health Bloomberg School of Public Health Baltimore, MD Presented to the Food and Drug Administration (FDA) Nonprescription Drugs Advisory Committee, Silver Spring, MD, on October 20, 2005

  2. Overview • Background • Primary exposures • Secondary exposures • Biocides in aquatic environments • Biocides in terrestrial environments • Biocides in food, drinking water, human milk, blood, and urine • Summary

  3. Properties of Important Environmental Contaminants • Toxic • Large quantities • Environmentally persistent • Exposure routes exist • Difficult to detect

  4. Accordingly, Polychlorinated Biocides May Be Problematic Triclosan (TCS) Triclocarban (TCC) For each molecule in water, we expect to find ~100,000 in fat

  5. Triclocarban:A chemical running under the radar Publications per year

  6. Known / Potential Environmental and Human Health Risks of Triclosan Degradates (including chloroform)  Impurities  Persistent Environmental Contaminant  Cross-resistance to Antibiotics  Triclosan Bioaccumulation  Acts as Carcinogen, Mutagen or Teratogen (No, at least not directly) Endocrine Disruption ?

  7. Known / Potential Environmental and Human Health Risks of Triclocarban Degradates  Impurities ?  Persistent Environmental Contaminant  Cross-resistance to Antibiotics ? Triclocarban Bioaccumulation ?  Acts as Carcinogen, Mutagen or Teratogen ?  (Plausible Connection) Endocrine Disruption ?

  8. Biocides Are Persistent Environmental Pollutants 10000 Triclosan 540 1000 Triclocarban 120 60 100 Estimated Half-life (days) 10 1 0.75 1 0.1 Air Water Soil Sediment Estimated using quantitative structure activity relationship (QSAR) analysis Halden and Paull, 2005, ES&T 39(6):1420-1426

  9. Overview • Background • Primary exposures • Secondary exposures • Biocides in aquatic environments • Biocides in terrestrial environments • Biocides in food, drinking water, human milk, blood, and urine • Summary

  10. Routes of Primary Exposure Primary Human exposure Ingestion Absorption (Inhalation) Sources of Biocides: Personal care products Plastics Textiles Laundry detergents Others Manufacturing byproducts Co-exposure

  11. Routes of Secondary Exposure Disposal Secondary Human exposure Sludge Wastewater WWTP Ingestion Absorption (Inhalation) Air Effluent Soil Water resources Drinking water Sediment Food (Plants and Animals) Bioconcentration Bioaccumulation Biomagnification Co-exposure Degradates & Metabolites

  12. Overview • Background • Primary exposures • Secondary exposures • Biocides in aquatic environments • Biocides in terrestrial environments • Biocides in food, drinking water, human milk, blood, and urine • Summary

  13. Triclocarban: 48 Years of Usage Before the First Publication on Its Environmental Fate

  14. TCC Contamination in Baltimore Streams Halden and Paull, 2005, Environ. Sci. Technol., 39(6):1420-1426

  15. Co-Occurrence of TCC and TCS in MD Streams TCC [ng/L] TCS [ng/L] Calculate TCC R2 = 0.9882 Measure TCS Halden and Paull, 2005, Environ. Sci. Technol., 39(6):1420-1426

  16. Prediction: TCC Contamination Nationwide

  17. Model Predicts Nationwide Contamination Halden and Paull, 2005, Environ. Sci. Technol., 39(6):1420-1426

  18. Predictions for 85 Streams Across the U.S. Halden and Paull, 2005, Environ. Sci. Technol., 39(6):1420-1426

  19. Toward an Inventory of Biocides inU.S. Water Resources Nationwide

  20. Jochen Heidler: Initial Data from the U.S. • • • • • • • • • River samples taken upstream and downstream of WWTPs in 9 states across the U.S. Sapkota, Heidler, and Halden (In Review)

  21. Preliminary Results Predicted Nationwide Contamination Was Confirmed Experimentally Model Experimental Upstream Downstream Number of samples 85 18 18 Detection Frequency 60% 56% 100% Mean [ng/L] 213 12±15 84 ±109 However, concentrations are low, in the ng/L range! Sapkota, Heidler, and Halden (In Review)

  22. Overview • Background • Primary exposures • Secondary exposures • Biocides in aquatic environments • Biocides in terrestrial environments • Biocides in food, drinking water, human milk, blood, and urine • Summary

  23. Typical U.S. Wastewater Treatment Plant (WWTP) • Activated sludge WWTP • 680 ML/d (180 MGD) • Population served: 1.3 Million Heidler and Halden, 2004

  24. Schematic Overview of Studied Activated Sludge Wastewater Treatment Plant (WWTP) Mechanical Screens Primary Secondary Sand Activated Sludge Treatment Chlorine Influent Clarifiers Clarifiers Filters Effluent Air Primary Secondary Sludge Sludge Solid Waste Sludge Thickeners Anaerobic Digesters Sampling Locations Dewatered digested sludge Heidler and Halden, 2004

  25. WWTP: Less Than 1 ppb in Effluent TCS 100000 TCC 10000 1000 100 10 1 ppb Accumulation < 1 ppb Influent Effluent Digested Sludge Heidler and Halden (In Preparation) Heidler and Halden (2004 Preliminary Estimate)

  26. But Substantial Accumulation in Sludge TCS 100000 TCC 10000 1000 100 10 1 ppb Accumulation < 1 ppb Influent Effluent Digested Sludge Heidler and Halden (2004 Preliminary Estimate)

  27. Fate of Biocides During Conventional Activated Sludge Wastewater Treatment 43% 54% 45% 54% 3% 1% (Data shown are based on a conservative 2004 estimate; revised estimates have been submitted for publication ) TCS TCC Mass in effluent Mass in sludge Mass degraded Heidler and Halden (2004 Preliminary Estimate)

  28. Estimated Mass & Use of Sludge in the U.S. Sludge: A Potential Resource: 12.5 Billion dry lb/yr Incineration 19% Other 1% Land Application 63% Landfills 17% After successful removal from wastewater, the majority of captured compounds is re-introduced into the environment Biosolids Applied to Land, National Research Council of the National Academies, 2002

  29. Biocides: Transfer from Water to Ag Soils • Plant removes but does NOT degrade biocides effectively • Biocides are transferred into municipal sludge • Concentration ratio sludge/effluent: ~100,000 • >150,000 lbs/yr of TCS and >175,000 lbs/yr of TCC are applied on agricultural land in sludge used as fertilizer • Neither biocide is approved/tested for use in agriculture Heidler and Halden (2004 Preliminary Estimate)

  30. Overview • Background • Primary exposures • Secondary exposures • Biocides in aquatic environments • Biocides in terrestrial environments • Biocides in food, drinking water, human milk, blood, and urine • Summary

  31. Are People Getting Unintentionally Exposed and What Are the Risks/Outcomes?

  32. Rare Infant Deaths From Laundry Disinfectants AJPH 60(5):901 (1970)

  33. 1967: Rare Deaths Due to Improper Use of Laundry Agents • 1967, Booth Memorial Hospital, St. Louis, MO • Infants: sweating, fever, difficulty breathing • 2 deaths, multiple illnesses • 2 drums of Loxene found in laundry closet • 22.9% chlorophenols • 4% triclocarban • Analysis of blood showed phenol poisoning AJPH 60(5):901 (1970)

  34. Methemoglobinemia in Infants: U.S. Pediatrics, February 1963 Committee on Drugs “...clinical judgment would dictate avoiding... even the most innocent-appearing substances in the nursery ...until data on toxicity are available...” (verbiage from final paragraph) Pediatrics, December 1971

  35. Human Exposure to Environmentally Persistent Biocides • Triclosan in drinking water resources (Multiple reports) • Triclocarban in fruit juice (Sapkota et al. unpublished) • Triclosan in fish (Multiple reports) • Triclosan in breast milk (1 Report published; 1 in preparation) • Triclosan/Triclocarban in human blood (WWF; Sapkota et al. unpublished) • Triclosan in humanurine (CDC, 2005)

  36. In Summary: The Biocides TCS and/or TCC... • persist in the environment • are produced faster than they degrade (unsustainable usage) • contaminate sludge, a potentially valuable resource • contaminate the food supply • bioaccumulate in biota (e.g., fish) • are detectable in human blood, milk and urine (general population) • contaminate soils and aquatic sediments; consequences unknown These known/potential risks need to be weight against potential benefits

  37. Acknowledgments • Daniel Paull, Jochen Heidler, Amir Sapkota, David Colquhoun, Rey de Castro • Guy Hollyday (Baltimore Sanitary Sewer Oversight Coalition) • John Martin and Nick Frankos from the Department of Public Works, City of Baltimore Triclocarban research was made possible by the • NIEHS grant P30ES03819 (Pilot Project) • JHU Faculty Innovation Award • CRF of Maryland • JHU Center for a Livable Future • JHU Faculty Research Initiative

  38. Selected References • Kolpin et al., Environ. Sci. Technol., 36:1202, 2002 • Halden and Paull, Environ. Sci. Technol., 38(18):4849, 2004 • Halden and Paull, Environ. Sci. Technol., 39(6):1420, 2005 • Okumura, Nishikawa, Anal. Chim. Acta, 325:175, 1996 • Latch, J. Photochem. Photobiol., 158:63, 2003 • Gledhill, Water Research, 9:649, 1975 • Clark et al., Int. J. Environ. Anal. Chem., 45:169, 1991 • Bester, Water Research, 37:3891, 2003 • Federle et al., Environ. Toxicol. Chem., 21:1330, 2002 • McAvoy et al., Environ. Toxicol. Chem., 21:1323, 2002 • Heidler and Halden, ACS National Meeting, Washington, DC, 2004.

  39. TCC in River Sediments Source: Wastewater Treatment Plant

  40. TCC in Human Urine • 30 Anonymous Adult Volunteers Lacking Occupational Exposures • 24 Had Detectable Levels of Triclosan • Mean 127 ng/mL = µg/L = ppb • 5th to 95th Percentile: <LOD to 702 ng/mL Ye et al. 2005 Anal. Chem. 77:5407-5413; Data from the CDC in Atlanta, GA

  41. Ecological Risk Posed by 3,4-Dichloroaniline Versteeg et al. 1999; Environ. Tox. Chem. 18(6):1329

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