Urine mutagenicity of farmers occupationally exposed during a 1-day use of chlorothalonil and insecticides.

OBJECTIVES

A study was conducted to evaluate the genotoxic impregnation consecutive to a 1-day open-field spraying of pesticides.

METHODS

From 14 farmers (five smokers and nine non-smokers), three urine samples were collected at the end of the spraying season: the morning (S1) of the day of spraying, the evening (S2) and the morning (S3) of the following day. A fourth sample (S0) was obtained before the pesticide-handling period. Mutagenicity of urine extracts was evaluated with the Ames test, using strains TA97a, TA98, TA100 and TA102, with and without S9 mix.

RESULTS

The ratio of induced vs spontaneous revertants (induction ratio) was > or =2 in five farmers (including three smokers), with only one strain responding in each. Applying the SALM software proposed by Kim and Margolin in combination with the ANOVA-Dunnett test on crude data (number of revertants), urine extracts were found to be mutagenic on at least one Salmonella strain in 57% and 96% of non-smokers and smokers, respectively. The proportion of mutagenic responses tended to increase from S1 to S3 (not statistically significant) in non-smokers only. Finally, there were no relationships between the relative changes in the number of revertants (adjusted for urine concentration) and any exposure parameters available: area sprayed, number of tanks prepared and time free of exposure to any pesticide.

CONCLUSIONS

The lack of significant relationships between urine mutagenicity and exposure data argues against a direct role of the pesticides sprayed, on this impregnation. This result should be considered with caution since the number of farmers involved may limit the significance of the study.