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SOURCES OF VARIATION IN THE MUTAGENIC POTENCY OF COMPLEX CHEMICAL MIXTURES BASED ON THE SALMONELLA/MICROSOME ASSAY
Citation:
Krewski, D., B. Leroux, J. Creason, AND L. Claxton. SOURCES OF VARIATION IN THE MUTAGENIC POTENCY OF COMPLEX CHEMICAL MIXTURES BASED ON THE SALMONELLA/MICROSOME ASSAY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/057 (NTIS PB92150713).
Description:
Twenty laboratories worldwide participated in a collaborative trial sponsored by the International Programme on Chemical Safety on the mutagenicity of complex mixtures as expressed in the Salmonella/ microsome assay. he U.S. National Institute of Standards and Technology provided homogeneous reference samples of urban air and diesel particles and a coal tar solution to each participating laboratory, along with samples of benzo(a)pyrene and 1-nitropyrene which served as positive controls. Mutagenic potency as characterized by the slope of the initial linear component of the dose response curve. nalysis of variance revealed significant interlaboratory variation in mutagenic potency, which accounted for 57-96% of the total variance on a logarithmic scale, depending on the sample, strain and activation conditions. ariation among replicate extractions of organic material (required for the air and diesel particles) and among replicate bioassays within the same laboratory was noteworthy. o significant differences were noted in the average potency reported for air and diesel particles between laboratories using soxhlet extracts and those using sonication, although there was larger interlaboratory variation for the soxhlet method.
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SOURCES OF VARIATION IN THE MUTAGENIC POTENCY OF COMPLEX CHEMICAL MIXTURES BASED ON THE SALMONELLA/MICROSOME ASSAY