Risk assessment for demal exposure of organophosphate pesticides in rice-growing farmers at Rangsit agricultural area, Pathumthani province, Central Thailand

Abstract

This cross-sectional descriptive study investigated the dermal route exposure of organophosphate pesticides and assessed the health risk due to Chlorpyrifos and Profenofos among rice farmers in the Rangsit Agricultural Area, Pathumthani Province, central Thailand. Interviews were conducted with 29 subjects to understand the characteristics of the rice farmers and pesticides use in the community. Neurological signs and symptoms that could be related to organophosphate pesticides existed among the community. The respondents generally could not identify the names of the pesticides which could cause their symptoms. The most common pesticides used were Chlorpyrifos, Dicroptophos and Abamectin. Neighbor influence was an important factor in pesticide purchasing. The surveyed farmers used at least one type of hazardous pesticide; often mixed more pesticides than recommended in each spray and even more if the previous application was ineffective, which shows that the sampled farmers are of particular concern since they were experiencing extensive potential exposure to harmful pesticides. For health risk assessment for dermal exposure portion, hand-wipe samples were collected from 14 subjects who sprayed organophosphate pesticides, specifically Chlorpyrifos and Profenofos. The residues of Chlorpyrifos and Profenofos contaminated on the hands of the rice farmers after they applied pesticides were quantified. The mean concentration of Chlorpyrifos was 10.48 mg/Kg, and concentrations ranged from 0.29 to 105.62 mg/Kg. The mean concentration of Profenofos was 4.38 mg/Kg, and concentrations ranged from 0.51 to 22.86 mg/Kg. The result of risk characterization indicated that the farmers may be at risk from Chlorpyrifos and Profenofos exposure (Hazard Index (HI), Chlorpyrifos and Profenofos >1). Long term dermal exposure of these two non-carcinogenic pesticides in these rice farmers may result in chronic adverse health effects.