AN ASSESSMENT OF THE GENETIC TOXICITY OF ATRAZINE - RELEVANCE TO HUMAN HEALTH AND ENVIRONMENTAL-EFFECTS

The genetic toxicity of atrazine, a member of the s-triazine herbicide s, was reviewed with the objective of classifying the chemical. Atrazi ne has been subjected to a broad range of genetic tests with predomina ntly negative results. Some publications, specifically those measuring dominant lethality in mice and bone marrow clastogenicity in rodents, reported conflicting results across two or more independent tests. Tw o approaches were employed to evaluate and interpret the results. The first approach attempts to classify each type of genetic endpoint as p ositive or negative and resolve test conflicts by critical assessment of the study and detailed data. This is the more traditional ''expert judgement'' approach to hazard assessment. The second approach employs a computer-assisted weight-of-evidence method of data analysis. This approach does not require resolution of conflicts but uses all data se ts to arrive at a classification of hazard. The first approach was abl e to resolve some conflicts but not all. Use of the ''expert judgement '' results in an equivocal conclusion and classification. Use of the w eight-of-evidence method resulted in a conclusion that atrazine does n ot pose a mutagenic hazard. The weight-of-evidence scheme is proposed to be a more practical and relevant approach for assessing complex dat a sets.