Non-occupational pesticide exposure and risk assessment among preschool children : case study in Bang Rieng agricultural community, Khuan Nieng district, Songkhla province

This study was designed to investigate non-occupational pesticide exposure among preschool children (2-5 years) living in Bang Rieng vegetable farming community. Four organophosphate (OP) pesticides, dicrotophos, chlorpyrifos, methyl parathion, and profenofos, were analyzed from soil, floordust, and dermal wipes (hands and feet) samples collected from 37 farm children living in or nearby the field, and 17 reference children outside the farmland. The common OP metabolites were also measured from children’s urine. All samples were collected covering two spraying seasons, dry season (high spraying) and wet season (less spraying). The results showed that the average of total urinary OP metabolite for the farm children (26.2 g/g creatinine) was significantly higher than for the reference (9.3 g/g creatinine) during the dry season. The farm children also had higher levels of the metabolite during the dry season compared to the wet season. In addition, the percentages of detectable for the four OP pesticides residue in soil, floordust, and children’s hands and feet were found to be higher in the farm children than in the reference. Seasonal pesticide spraying, therefore, is an important factor for the children’s pesticide exposure. The results from multiple regression analysis showed that some children’s behaviors including, putting hand into the mouth, walking barefeet outside their home and frequent playing in the field were significantly positively associated with the OP exposures. The levels of dicrotophos on hands and profenofos on feet for the farm children were also significantly associated with the increasing levels of the urinary metabolites. The potential non-occupational exposure pathways for the children in this study consist of soil ingestion, hand mouthing, soil dermal contact, and surface residue contact. Non-carcinogenic hazard estimation indicated that non hazard effect was found from each exposure pathway for both the study groups. However, it was found that the average of the sum of hazard index for each pathway of the farm children in the dry season exceeded the acceptable values (Hazard Index, HI>1), whereas no significant hazard was found for the reference in both seasons.