Genotoxic damage in a Bolivian agricultural population exposed to a mixture of pesticides

Abstract

TPS 792: Occupational health 2, Exhibition Hall, Ground floor, August 27, 2019, 3:00 PM - 4:30 PM Pesticides are well-known chemicals that can increase the risk to develop cancer by induction of DNA damage and oxidative stress, especially in populations with chronic exposure. Bolivian farmers have been increasing their use of pesticides during the last decades to increase their production and economy. Chronic exposure to these chemicals, their combined effects and genetic polymorphisms can increase the risk of genotoxic damage, mutagenicity and development of chronic diseases. A cross-sectional study in 297 volunteers from three different Bolivian agricultural communities was conducted. Exposure and handling of pesticides were assessed by a questionnaire and urinary pesticide metabolite analysis. Genotoxic effects were evaluated in collected blood samples by Micronucleus and Comet assay. Frequency of glutathione transferase (GST) null genotypes (GSTM1 and GSTT1) was determined to evaluate the impact on DNA damage levels. The results showed that only 17% of the farmers used recommended protection equipment. In agreement, they were highly exposed to chlorpyrifos, pyrethroids and 2,4-D, and men generally more highly compared to women. Higher frequency of micronuclei (MN) was found in women compared to men (4.52 vs 3.55, p<0.05). Farmers active >8 years had higher frequency of MN compared to farmers active <8 years (4.23 vs 2.94, p<0.05). Surprisingly, a null GST genotype (GSTM1 and GSTT1: 84% and 24% null, respectively) was associated with lower levels of DNA damage. High levels of exposure to tebuconazole, 2,4-D or cyfluthrin was associated with high levels of DNA strand breaks (p<0.05-0.01). After adjustment for confounding factors (e.g. gender, age, GST genotype), a significant increased risk of DNA strand breaks was found for exposure to 2,4-D (OR=1.9, CI=1.0-3.8, p=0.049). In conclusion, agricultural Bolivian population, especially men are highly exposed to mixtures of pesticides causing genotoxic effects in lymphocytes and which constitutes an increased risk of developing cancer in the future.