Clastogenicity of atrazine assessed with the Allium cepa test.

Atrazine is classified as a restricted use pesticide and it is currently included in an international revision program for re-evaluating the human and ecological (non-human populations) health risks associated with its release into the environment. The present study was undertaken to add new data on the genotoxic potential of atrazine using the Allium cepa chromosome aberration test. The test concentrations were based on the Maximum Contaminant Levels in water intended for human consumption set by European and US regulations. Atrazine produced a concentration-related increase in the number of total somatic chromosome aberrations, although this increase was statistically significant (p<0.05) only at the highest test concentration (5 microg/L). Analysis of the categories of structural chromosome damage indicated that breaks were the predominant lesion induced; the percent of cells per bulb with breaks also increased in a concentration-related manner, and the increase was statistically significant at the two highest test concentrations (1 and 5 microg/L) (p<0.05). The Allium cepa plant assay detected the clastogenicity of atrazine at concentrations that are likely to be encountered in water, a common site of atrazine contamination. Copyright 2004 Wiley-Liss, Inc.