Study on biological monitoring of fenpropathrin exposure in application by utilizing urinary 3-phenoxybenzoic acid level

To estimate pesticide exposure faced by applicators, an investigation of exposure-absorption was conducted on two applicators under routine working conditions and using regular procedures during pesticide spraying of greenhouse strawberries with fenpropathrin. The authors hypothesized that 3-phenoxybenzoic acid (3-PBA) is a urinary excreted metabolite of fenpropathrin, a synthetic pyrethroid pesticide with 3-phenoxybenzyl moiety, and its determination would help to improve the assessment of fenpropathrin exposure-absorption in applicators. The extent of exposure-absorption was evaluated by the determination of urinary level of 3-PBA (biological monitoring), the amount of the chemical adhered to clothes and permeated to the skin surface, and its concentration in the air of the greenhouse. The results showed that the fenpropathrin concentration in the air was less than 0.1 μg/m³. The amount of adhesion was less than 0.001 to 10.25 μg/cm², and there was very little permeation. However, the urinary 3-PBA concentration by biological monitoring appeared to be approximately twice that of pre-exposure levels in both applicators. This finding demonstrates that the applicators were exposed to fenpropathrin and absorbed it during spraying. We conclude that the fenpropathrin exposure-absorption in application could be estimated by the determination of urinary 3-PBA. This method of biological monitoring may be more useful indicator to accurately evaluate the working conditions in application.