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Occupational exposure to pesticides and thyroid function in Brazilian soybean farmers

Bernieri, Tanandra, Rodrigues, Dabiana, Barbosa, Isadora Randon, Ardenghi, Patrícia Grolli, Basso da Silva, Luciano
Chemosphere 2019 v.218 pp. 425-429
agricultural productivity, blood sampling, blood serum, cholinesterase, endocrine-disrupting chemicals, epidemiological studies, farmers, humans, nontarget organisms, occupational exposure, pest control, pesticides, plant protection, risk, soybeans, thyroid function, thyrotropin, triiodothyronine
Agriculture production has been supported especially by the use of pesticides for crop protection and pest control. Although the agricultural production has been increased by pesticides use, these substances also reach non-target organisms and may become a risk to the health of farmers. Several epidemiological studies in human have investigated the association between exposure to pesticides and altered serum levels of thyroid hormones, reporting both positive and negative results. Overall, the impact of pesticides on human thyroid function is still limited.The aim of this study was to access serum levels of free thyroxin (FT4), total triiodothyronine (TT3), thyroid-stimulating hormone (TSH), and butyrylcholinesterase (BChE) in soybean farmers in southern Brazil.The exposed group was composed by 46 rural workers and 27 subjects not exposed to pesticides composed the control group. All subjects had blood samples collected by venipuncture in order to analyze the serum levels of FT4, TT3, TSH and BChE.The results showed a significant decreasing in TSH and increasing in TT3 and FT4 in rural workers, compared to control group. BChE levels were lower in exposed group than in control group. The results suggest that farmers are exposed to mixtures of pesticides with endocrine disruptor properties.