Tuesday, July 20, 2010

US Agencies Work Together to Develop Chemical Screening Methods

One of the big questions regarding the new TSCA reform discussions is how exactly will companies meet any data obligations imposed by the new law. In the past any "data" request was expected to be filled by animal testing, but the animal welfare advocates and a realization of the limitations of animal testing have led many to look for alternative testing techniques.

The Tox21 collaboration merges the resources (research, funding and testing tools) of several US agencies "to develop ways to more effectively predict how chemicals will affect human health and the environment." The agencies include the EPA, the National Institute of Environmental Health Sciences (NIEHS) National Toxicology Program (NTP), the National Institute of Health (NIH) Chemical Genomics Center (NCGC), and most recently the Food and Drug Administration (FDA).

Through the collaboration the agencies hope to develop methods to screen all chemicals for risk quickly, efficiently, and in most cases without the use of animal testing. About 2,000 chemicals "have already been screened against dozens of biological targets," with hopes of getting that number up to five times that much by the end of this year. Eventually all 85,000+ chemicals on the market will have had at least an initial screening, which will help prioritize any chemicals of concern for more closer analysis.

A major component of the Tox21 collaboration is development of rapid and automated methods, which is the focus of a testing program called ToxCast. Many of these methods use sensitive cell culture and even genomic markers to screen for toxicity rather than going directly to standard animal testing. The idea is "high-throughput," i.e., screening a lot of chemicals fast so that those that are clearly not toxic can be put aside, those that are clearly very toxic can be prioritized, and those that are somewhere in the middle can get more targeted testing to address the specific questions raised.

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