Comprehensive Environmental Assessment and U.S. EPA Nanomaterial Case Studies

Transcription

1 Comprehensive Environmental Assessment and U.S. EPA Nanomaterial Case Studies J. Michael Davis, Ph.D. Senior Science Advisor, U.S. EPA, Research Triangle Park, NC Amy Wang, Ph.D. Postdoctoral Fellow, EPA-DOE Interagency Agreement, RTP, NC Maureen Gwinn, Ph.D. Biologist, U.S. EPA, Washington, DC Jo Anne Shatkin, Ph.D. Managing Director, CLF Ventures, Boston, Mass. NATO Advanced Research Workshop Risk, Uncertainty and Decision Analysis for Nanomaterials: Environmental Risks and Benefits and Emerging Consumer Products Faro, Portugal -- April 27-30, 2008

2 Outline Comprehensive Environmental Assessment Life Cycle + Risk Assessment Diversity of perspectives Structured process Case Studies Examples Current Status & Next Steps

3 Look at the Big Picture!

4 Comprehensive Environmental Assessment (CEA) CEA LC + RA LC = Product Life Cycle framework RA = Risk Assessment paradigm See: Davis, J. M. How to assess the risks of nanotechnology: learning from past experience J. Nanosci. Nanotechnol. 7(2): , 2007

5 Product Life Cycle Feedstocks Manufacturing Distribution Storage Use Disposal

6 Risk Assessment Dose-Response Assessment Hazard Identification Exposure Assessment Risk Characterization

7 Comprehensive Environmental Assessment Life Cycle Stages Environment Pathways Fate & Transport Exposure Effects Feedstocks Manufacture Distribution Air Water Primary contaminants Biota Ecosystems Storage Use Soil Food chain Secondary contaminants Human populations Health Disposal

8 CEA Features Qualitative > quantitative Comparative: Alternative choices Risks vs. benefits Guidance to risk managers: Highlights trade-offs Focus for monitoring, mitigation Adaptive management Identifies: Information gaps Research priorities

9 Process Focus on draft case studies Obtain a variety of technical & stakeholder perspectives Use expert judgment methods Repeat periodically

10 Case Studies EPA Nanotechnology White Paper (2007) recommendation Goal: identify & prioritize research needed for comprehensive assessment of nanomaterials Selected applications within classes of nanomaterials: Nanoscale titanium dioxide (nano-tio 2 ) Nanoscale silver (nano-ag)

11 Case Studies (cont d.) Selection Criteria: Current or future exposure potential Environmental as well as human relevance Nano-ness Relevance to EPA programs Data availability Case Study (CS) topics: CS#1 nano-tio 2 for water treatment CS#2 nano-tio 2 in sunscreen lotion CS#3 nano-ag not yet determined Note: Case Studies are not completed assessments

12 Acute nano-tio 2 Aquatic Toxicity Tests EPA/OPPT Hazard Ranking Daphnids 48 hr LC 50 = 5.5 mg/l Medium concern 48 hr EC 50 > 100 mg/l Low concern Algae 72 hr growth EC 50 = mg/l Medium concern 96 hr LC 50 > 100 mg/l Low concern Fish

13 Indirect and Interactive Effects May Be Significant In fish, nano-tio 2 increases uptake of: Arsenic (Sun et al., 2006) Cadmium (Zhang et al., 2007) What are implications for: Enhanced toxicity? Uptake/toxicity of other contaminants? Similar effects in other species?

14 CEA Case Study Water Treatment Life Cycle Stages Environment Pathways Fate & Transport Exposure Effects Feedstocks Manufacture Distribution Storage Use Disposal Air Water Soil Food chain Primary contaminants Secondary contaminants Aggregate Cumulative Ecosystems Human Health

15 CEA Case Study Water Treatment Life Cycle Stages Environment Pathways Fate & Transport Exposure Effects Feedstocks Manufacture Distribution Storage Use Air Water Soil Food chain Inhalation Primary contaminants Ingestion Secondary contaminants Absorption Injection Ecosystems Human Health Disposal

16 Currently: Current Status & Next Steps CS#1 (nano-tio 2 : water treatment) external review (peer consultation) completed, draft in revision CS#2 (nano-tio 2 : sunscreen) reviewed by internal workgroup, draft in preparation for external review CS#3 (nano-ag) application to be determined Planned: Solicit public comment / input Hold expert judgment workshop Publish Research Strategy