US agency chastened by criticism, but not surprised
The US Environmental Protection Agency (EPA) needs to significantly improve its chemical risk assessments, or their value and credibility ’will erode’, the country’s National Research Council (NRC) has warned.
The agency is ’struggling to keep up with demands for hazard and dose-response information and is challenged by a lack of resources’, says the NRC in its 3 December report, Science and Decisions: Advancing Risk Assessment, which was requested by the EPA.
’There have been some important risk assessments that have taken forever and still haven’t been satisfied,’ says Lorenz Rhomberg, a quantitative risk assessment expert with Gradient Corporation, an environmental science consulting firm based in Cambridge, Massachusetts, US.
One example noted by the NRC is EPA’s risk assessment of trichloroethylene, which has been under development since the 1980s and is not slated for completion until 2010. A chlorinated hydrocarbon, trichloroethylene is often used as an industrial solvent and is a common contaminant in soil and groundwater. It has been linked to cancer and other health problems.
Besides trichloroethylene, Rhomberg cites EPA’s considerable delays in assessing the health risks associated with dioxins and formaldehyde, as well as the carcinogenicity of arsenic.
EPA welcomed the report’s release, calling the findings unsurprising. ’As science and research methodology changes and evolves over time, EPA expects to continue to update and change how we do conduct risk assessments,’ agency spokesperson Suzanne Ackerman tells Chemistry World.
The American Chemistry Council (ACC), the major industry trade association for US chemical companies, agrees that EPA’s chemical risk assessment process is lacking. ’EPA has had difficulty keeping up with the science of risk assessment,’ states Rick Becker, a senior toxicologist at ACC.
The NRC panel recommends that EPA focus on the questions that policy-makers want answered before running through the usual risk assessment framework of identifying hazards, dose-response relationships, exposures, and risks. It hopes that careful early planning addressing the needs of users will cut down on unnecessary analysis.
The panel pointed out that the science of risk assessment is becoming more complicated. Improved analytical techniques are now raising questions about the role of differing susceptibility to chemicals among different populations, and the need to assess the risks of exposure to multiple chemicals.
The NRC suggests the agency move to consider chemicals under a more unified assessment framework, including an evaluation of background exposures, disease processes, possible vulnerable populations, and various modes of action that may affect human dose-response relationships. It also calls for better analyses of variability and uncertainty in dose-response curves during the risk assessment process.
EPA says it will thoroughly review the NRC recommendations and develop an implementation plan. Concern remains, however, that some of the report’s proposals may be overly complicated and rigid.
’Risk assessments lack credibility if it seems as though they are just a recipe for endless wrangling about things that can never be finished,’ warns Gradient’s Rhomberg. ’You don’t want tonnes of different EPA offices doing risk assessments on one chemical all because they have slightly different purposes or missions.’
Rebecca Trager, US correspondent for Research Day USA
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