SOURCE: Gradient


April 14, 2011 13:20 ET

Gradient Scientist Testifies Before House Subcommittee on Proposed Coal Combustion Residuals Regulations

CAMBRIDGE, MA--(Marketwire - Apr 14, 2011) - Gradient scientist Ari S. Lewis was invited by the House Subcommittee on Energy and the Environment as an expert in toxicology and human health risk assessment to provide scientific testimony regarding H.R. Bill 1391 on the Recycling Coal Combustion Residuals Accessibility Act of 2011. The hearing was held April 14, 2011 in Washington, DC.

In 2010, the U.S. Environmental Protection Agency (US EPA) issued proposed rules to regulate coal combustion residuals (CCR), one of which considered regulating CCR as hazardous waste under Subtitle C of the Resource Conservation and Recovery Act (RCRA). Concerns have been raised that the proposed rule would pose an impediment to the recycling and beneficial uses of coal combustion products (CCPs).

The US EPA analyses supporting its proposed rule included a series of human health risk assessments which evaluated the potential release and human exposure to constituents in CCR managed in landfills and surface impoundments. The US EPA's analyses found that the only potential exposure pathway of possible health concern was leaching of CCR constituents to groundwater.

Ms. Lewis testified that regulating CCR as hazardous waste is not adequately supported by the US EPA risk assessments which found, with the possible exception of arsenic, that CCR management under typical practices did not pose health risks above Agency-defined guidelines. However, arsenic risks were not distinguishable from risks associated with intake of naturally occurring arsenic in food, water, soil and air. Ms. Lewis also cautioned the US EPA "high end" residuals management scenarios contained large uncertainties and was not sufficiently constrained to be useful in quantifying possible risk reduction among different regulatory options.

Ms. Lewis is a senior environmental toxicologist who has focused her academic and professional career on metals toxicology and risk assessment. An expert on arsenic toxicology, she has also evaluated the human health risks of other metals, including selenium, lead, mercury, thallium, molybdenum, and chromium. Ms. Lewis holds a B.A. from the University of Pennsylvania and an M.S. in Environmental Toxicology from Cornell University.

About Gradient
Gradient is an environmental and risk science consulting firm renowned for its specialties in Toxicology, Epidemiology, Risk Assessment, Product Safety, Contaminant Fate and Transport, and Environmental Chemistry. Click to view Ms. Lewis's scientific testimony.