Genomics Testing

U .S. and european officials informally agreed last week to use genomics techniques to test whether chemicals can be lumped together in categories of similar characteristics for toxicity assessment.

Such categories are employed in U.S. and international efforts to gather toxicity information about commercial chemicals produced in large amounts. Under a U.S. initiative, manufacturers of high-production-volume (HPV) chemicals--those produced in quantities of 1 million lb or more per year--are voluntarily providing data on more than 2,200 substances. Meanwhile, the International Council of Chemical Associations is compiling basic data on 1,000 HPV chemicals for the Organization for Economic Cooperation & Development.

In both efforts, manufacturers have placed chemicals into groups so that toxicity data from one compound can be extrapolated to others in the same category, rather than testing each substance individually. Although this approach is innovative, regulators and environmental groups have questioned the basis for some of the groupings.

At the U.S.-European Union Transatlantic Environment Conference on Chemicals, held on April 26-28 in Charlottesville, Va., Ellen Silbergeld, a Johns Hopkins University professor, challenged regulators and industry to run toxicogenomics tests on categories of HPV chemicals to determine if chemicals grouped together do have like toxicity. She suggested comparing the results to determine whether there are similar patterns of genes turning off or on due to exposure to chemicals in a category.

Charles M. Auer, director of EPA's Office of Pollution Prevention & Toxics, said it would be useful to know whether chemicals in a group provide consistent responses in gene arrays--even if regulators do not know how to interpret the results into possible health effects.

Cornelis (Kees) van Leeuwen, of the European Commission's Joint Research Center, said EU officials would work with the U.S. on a plan for such tests.