Health risk assessment of dermal exposure to chlorpyrifos among applicators on rice farms in Ghana

Generally, there is limited information on pesticide absorbed dose levels and health risk attributable to the dermal route of exposure among applicators. The objective of this study was to evaluate the absorbed dose levels and consequent health risk from dermal exposure to chlorpyrifos among applicators on rice farms in Ghana. The whole-body dosimetry technique was used to capture chlorpyrifos residues penetrating the applicators’ clothing and reaching their skin, as well as residues reaching uncovered body areas of the applicators. Acute (ADD_D) and chronic (LADD_D) absorbed dose levels of chlorpyrifos were estimated from the residues and plotted as cumulative probability distributions. Health risk from chlorpyrifos exposure was characterized using the Hazard Quotient (HQ) technique. Three of the four acute exposure guideline values used in the study indicated that applicators, represented by the median-exposed (ADD_D, 15 μg/kg/day) and the 5% - highly exposed (ADD_D, 27 μg/kg/day) groups were at high risk of acute adverse health effects due to chlorpyrifos exposure, with HQ values ranging from 1.5 to 5 and 2.7 to 9, respectively. Regarding chronic adverse health effects, none of the guideline values suggested risk among the median-exposed group (LADD_D, 0.3 μg/kg/day), with HQ values ranging from 0.03 to 1. However, two of the chronic exposure guideline values suggested that the 5%- highly exposed group (LADD_D, 0.6 μg/kg/day) may be adversely affected, with HQ values ranging from 1.2 to 2. These findings highlight the importance of the dermal route as a major pesticide exposure pathway and suggest possible exposure minimization strategies.