Human exposure to neonicotinoid pesticides in the South-West and Littoral Regions of Cameroon

Abstract: Neonicotinoids are increasingly used in many countries around the world including Cameroon, to control pests involved in crop destruction or disease transmission. Unfortunately, the pesticides also pose tremendous environmental problems as a predominant amount of their residues enter environmental matrices to affect other non-targeted species including humans. Therefore, biomonitoring of neonicotinoid exposure in human populations is of great importance. The current study sought to assess neonicotinoid exposure in two agrarian regions of Cameron. The study involved 188 men including 125 farmers who used agro pesticides for crop protection, and a reference population of 63 men who were not involved in agro pesticide use. Spot urine samples were obtained from these subjects and subjected to LC-MS/MS analysis for concentrations of neonicotinoid compounds, including acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, nitenpyram, thiamethoxam and N-dm-acetamiprid. Neonicotinoid compounds were detected in 80.30% of the study population; and all the targeted pesticide residues were detected among participants except nitenpyram. Acetamiprid and imidacloprid were the most prevalent among the subjects. The farmers were more exposed to multiple neonicotinoid residues than the reference group, with higher overall pesticide levels and imidacloprid levels. The daily exposures of the detected neonicotinoids ranged from 0.017 to 0.161 µg/kg/day for dinotefuran and imidacloprid, respectively, and was also elevated among farmers. Although exposure levels of the neonicotinoids were generally lower than their respective reference doses, these results warrant further research on the health risk evaluation of multiple residues of the pesticides and reinforcement of control measures to minimize the exposure risks.
Keywords: agro pesticide, biomonitoring, neonicotinoid, occupational exposure