Recent Findings from Human Health and Ecological Risk Assessments of Waste to Energy Technologies

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1 Recent Findings from Human Health and Ecological Risk Assessments of Waste to Energy Technologies Society for Risk Analysis Annual Meeting Baltimore, Maryland December 8-11, 2013 Paul C. Chrostowski Sarah A. Foster CPF Associates, Inc.

2 Why Are WTE Risk Assessments Performed Usually response to public concerns about human health Sometimes response to ecological or natural resource concerns Rarely regulatory requirement

3 Some Milestones in WTE Health Evaluation History 1980 s Early risk assessments Opposition (dioxin, mercury, incinerator risk assessments) 1990 s Risk assessment guidance (California, human health - US EPA HHRAP, ecorisk - USEPA SLERAP) US EPA New Source Performance Standards (NSPS) 2000 s + Comprehensive reviews (US National Academy of Sciences, UK Health Protection Agency) Revised risk assessment guidance (US EPA HHRAP) EU Waste Incineration Directive (WID)

4 The Past Two Decades Implementation of regulations (US/EU) Standardization of risk assessments (HHRAP) Numerous studies of potential WTE impacts The potential for WTE to impact public health and environment is significantly different today than in the past

5 Risk Assessments Many risk assessments conducted in the past decade Facilities designed and operated to comply with current regulations (US/EU)

6 Compounds Evaluated in Human Health Assessments Note: PCDDs/PCDFs and PCBs each counted as 1 compound class All included Dioxins/furans and Hg Most included acid gases and several metals Rarely included ultrafine particles (qualitatively)

7 Exposure Pathways Evaluated Standard HHRAP suite almost always addressed Multiple pathway hypothetical exposure to multiple locally-raised animal food products usually included

8 Types of Health Risks Excess lifetime cancer risk Noncancer health effects (hazard index) Acute inhalation risk Exposure to infant from breast-feeding Ecological risks (inclusion varies) Criteria pollutants, GHGs treated separately

9 Maximum Excess Lifetime Cancer Risks Map shows maximum result among all evaluated scenarios in each assessment. All other results lower. Benchmark levels: One in 1,000,000 (1E-6) to one in 100,000 (1E-5)

10 Compounds Evaluated in Ecological Risk Assessments Five of the 10 risk assessments included an ecological component Note: PCDDs/PCDFs and PCBs each counted as 1 compound class All included Dioxins/furans and Hg All evaluated aquatic life, birds, mammals Some evaluated soil invertebrates and plants Some included food chain exposure calculations

11 Results from the EU Many EU risk assessments also rely on HHRAP methods Italy - health risks due to emissions modern WTE facility well below maximum acceptable levels, relatively small health significance for the surrounding population, very small compared to background cancer risk levels Spain potential carcinogenic and non carcinogenic risks less than regulatory threshold values; modern WTE plants do not pose significant human health risks UK no significant risk to human health associated with emissions from proposed EfW facility in Plymouth; cancer risks < UK benchmark of 1 in one million; non-cancer results well below reference levels

12 Model Refinements Sometimes Necessary Focus on risk drivers Example: mercury - Highest noncancer risks typically associated with methyl Hg in fish - HHRAP recommends SERAFM as alternative to default modeling approach (more refined) - Fish tissue concentrations and fish ingestion noncancer risk results >40 times higher using HHRAP vs SERAFM

13 Risk Assessment Observations USEPA HHRAP provides standardization, conservatism Facilities designed and operated to comply with US/EU regulations are protective of public health PCDD/Fs and Hg are most common risk drivers Bioaccumulative pathways (beef, milk, fish consumption) dominate risks Cancer risks, non-cancer hazards, ecological hazards below benchmarks

14 Do Risk Assessments Answer Public Health Issues? Honolulu, HA - risks are 50 to 3,333 lower than the USEPA s combustion facility benchmark for cancer risk, 50 to 5,000 times lower than USEPA s noncancer risk benchmark. Montgomery County, MD - relative risk is very low... Results indicate a very low chance (less than 1 chance in 1 million) for occurrence of potential carcinogenic health effects, and that no adverse noncarcinogenic health effects are expected... Lee County, FL - potential risks from stack emissions from the expansion of the Lee County ERF, in its proposed configuration with three combustion units, are below regulatory and other target risk levels for both human health and ecological receptors.

15 Current and Future Research Open source availability of all assessments Inclusion of ultrafine particles, criteria pollutants, GHGs Integration of epidemiology and risk assessment Standardization of ecological risk assessment