Transfer factor calculated using dermal exposure and dislodgeable foliar residue and exposure assessment for reentry worker after pesticide application in cucumber field

This study aimed to determine the transfer factor (TF) of methidathion for cucumber harvesters in greenhouses using the dermal exposure rates (DERs) and dislodgeable foliar residues (DFRs) measured simultaneously in my previous works. The DERs recalculated using the reference body surface area for the Korean adult males were 31.5–1281.1 μg/h, and the DFR values were 12.1–222.5 ng/cm² over 7 d after application. A strong correlation between the DERs and DFRs was observed, with a regression coefficient of 0.9982. The TF for cucumber harvesters in greenhouses was determined to be 6020.4 cm²/h, which was five times higher than that proposed by the US Environmental Protection Agency (EPA). Additionally, based on TF value of methidathion, the reentry intervals (REIs) with or without personal protective equipment (PPE) were estimated for 82 pesticides registered on cucumber. The REIs with PPE, obtained from acceptable operator exposure levels and TF value, were less than 0 d, indicating the lowest risk possibility. However, REIs without PPE were estimated between 0.04 and 4.4 d for seven pesticides, including chlorothalonil, emamectin benzoate, flubendiamide, fluquinconazole, iminoctadine tris(albesilate), propineb, and pyridaben. In conclusion, cucumber harvesters should wear PPE for health safety when they reenter the greenhouse to harvest cucumbers following application of pesticides.