Frequency of sister-chromatid exchange among greenhouse farmers exposed topesticides

Sister-chromatid exchange (SCE) was measured in peripheral lymphocytes of 1 04 greenhouse farmers exposed to pesticides and 44 unexposed workers. The r esults of SCEs are expressed in two variables: (a) mean number of SCEs per chromosome and, (b) proportion of high frequency cells (cells with more tha n eight SCEs). A high correlation was found between these two variables. Th e adjusted means of both SCEs variables were significantly higher among the farmers compared with the unexposed group (P < 0.01). Adjustment was made for smoking, age, education, and origin. The adjusted means of both SCE variables, were significantly elevated (P < 0.05) among the farmers who prepared and applied more than 70% of the pesti cides by themselves compared with those who prepared and applied less than 70% of the pesticides by themselves. Both SCEs variables were also signific antly elevated (P < 0.05) among farmers who were involved in more than 7.4 sprays per year compared with those with 7.4 or less sprays per year (P < 0 .05). We found a tendency towards elevation of the two variables of SCEs am ong those who did not use protective measures while preparing the pesticide s. Evaluation of the influence of years of exposure on the frequency of SCEs s howed that the two variables of SCEs were higher among those farmers who we re exposed to pesticides for more than 21 years than among those with less than 21 years of exposure. The variables that had the most influence on the elevation of SCEs were self-preparation of the pesticide mixtures and the number of sprayings per year. Because the farmers used a mixture of almost 24 different chemical classes it was impossible to attribute exposure to a specific pesticide or group of pesticides to single farmers. Our finding of a significant increase of SCEs frequency in peripheral lymph ocytes in greenhouse farmers indicates a potential cytogenetic hazard due t o pesticides exposure. (C) 2001 Elsevier Science B.V. All rights reserved.