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Environmental Safety of NP and NPE

Presentation Overview. Why the interest in NP/NPE?What are the Use and Disposal Patterns?What is the State of the Science on Exposure and Effects?What is the Relative Hazard of NPE and its degradation intermediates?What Can We Conclude about NP/NPE?. Why the Interest in NP/NPE?. Interest in NP/

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Environmental Safety of NP and NPE

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    1. Environmental Safety of NP and NPE Dr. Ellen Mihaich APERC Teleconference Series June 20, 2003

    2. Presentation Overview Why the interest in NP/NPE? What are the Use and Disposal Patterns? What is the State of the Science on Exposure and Effects? What is the Relative Hazard of NPE and its degradation intermediates? What Can We Conclude about NP/NPE?

    3. Why the Interest in NP/NPE? Interest in NP/NPE biodegradability in the early 1980s Connection of NP to the Endocrine Issue in the early 1990s High volume, ubiquitous chemical

    4. Chemical Structures

    5. General Uses of NPE Industrial Processing (~50%) Textiles, Pulp and Paper, Metal Processing, Emulsion Polymers and Coatings, Paints Industrial, Institutional, and Household Cleaning (~50%) Laundry Detergents, Hard Surface Cleaners, Agricultural Chemicals (inerts) Personal Care (<1%)

    6. Use and Disposal Patterns Application Disposal Practice Institutional and household cleaning products Industrial processing aids Paints and Coatings Pesticide formulations Down the drain to treatment plant On-site treatment or pre-treatment Remain encapsulated Sprayed onto foliage and soil

    7. State of the Science Exposure NP and NPE are biodegradable NP/NPE are effectively removed (>95%) from effluent in well-functioning secondary sewage treatment plants NP and NPE do not bioaccumulate and are not PBT compounds Levels of NP/NPEs found in monitoring studies typically well below ppb level However, environmental levels of concern can exist where treatment is inadequate

    8. State of the Science Environmental Exposure USGS Study (2001) Monitored for 95 substances in worst-case effluent-dominated streams e.g., caffeine, cholesterol, estrogen, pharmaceuticals and various chemicals Levels of NP/NPEs found were consistent with previous studies (Only 4 of 85 samples had NP > draft EPA Water Quality Criteria of 5.8 ppb)

    9. Degradation Pathway Shortening of the EO chain proceeds via formation of carboxylated intermediates (NPEC) Oxidation continues until EO chain shortened to NPE1,2 Enzymatic opening and mineralization of aromatic ring NPE fully biodegrade to CO2 and H2O, even the aromatic ring portion

    10. State of the Science Effects Numerous aquatic studies with NP/NPE/NP ether carboxylates (NPEC) with dozens of species Endpoints include standard toxicity endpoints (survival, growth and reproductions) as well as subtle biochemical changes Aquatic toxicity not endocrine issues drive risk assessment conclusions

    11. What is the Relative Hazard of NPE and the Degradation Intermediates?

    12. Data Review Process and Relative Hazard Assessment Critically reviewed chronic toxicity data Chronic Values (ChV) calculated ChV plotted according to EO chain length by endpoint Species sensitivity distribution Exposure compared to hazard for cumulative risk

    13. Chronic Values for Fish (F), Invertebrates (INV) and Algae (ALG) by NPEx + Survival ChV x Growth ChV ? Repro ChV

    14. Species Sensitivity Distribution NP

    15. Contribution of NPE, NPEC, NP to Total Hazard Quotient (HQ) in US Surface Waters

    16. Conclusions NPEs are widely used and well studied surfactants They are present in many industrial and down-the-drain applications Considerable aquatic toxicity data exists for the parent as well as the degradation intermediates Risk Assessment conclusions are not driven by endocrine activity

    17. Conclusions Typical concentrations of NP/NPEs in the environment are very low NP is a minor degradation intermediate Cumulative exposure assessment compared to hazard shows concentrations in the surface water do not exceed a safe level The draft EPA Water Quality Criteria (~ 5.8 ppb) is supported by this assessment

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