Personal air sampling and biological monitoring of occupational exposure to the soil fumigant cis-1,3-dichloropropene

Objectives-To assess exposure of commercial application workers to the nema tocide cis-1,3-dichloropropene (cis-DCP). Methods-The study was conducted during the annual application season, Augus t to 15 November, in the starch potato growing region in The Netherlands. 1 4 Application workers collected end of shift urine samples on each fumigati on day (n=119). The mercapturic acid metabolite N-acetyl-S- (cis-3-chloro-2 -propenyl)-L-cysteine (cis-DCP-MA) in urine was used for biological monitor ing of the cis-DCP uptake. Inhalatory exposure was assessed by personal air sampling during a representative sample (n=37) of the fumigation days. Ext ensive information was collected on factors of possible relevance to the ex posure and the application workers were observed for compliance with the st atutory directions for use. The inhalatory exposure during all fumigation d ays was estimated from the relation between the personal air sampling data and the biological monitoring data. Exposure levels were correlated with th e general work practice. The fumigation equipment and procedures were in ac cordance with the statutory directions of use, with the exception of the an tidrip systems. Two antidrip systems were used: antidrip nozzles or a compr essed air system. Results-The geometric mean exposure of the application workers was 2.7 mg/m (3) (8 hour time weighted average); range 0.1-9.5 mg/m(3). On 25 days (21%) the exposure exceeded the Dutch occupational exposure limit (OEL) of 5 mg/ m(3). This could mainly be explained by prolonged working days of more than 8 hours. The general work practice of the application workers was rated by the observers as good or poor. No difference in exposure to cis-DCP was fo und in the use of none, one, or two antidrip systems. Malfunctioning of the antidrip systems and lack of experience with the compressed air system wer e identified as possible causes for the lack of effectiveness of these anti drip systems. The use of personal protection was not always in accordance w ith the statutory directions of use. Dermal exposure to liquid cis-DCP was found four times during repair and maintenance, but the biological monitori ng data did not suggest a significant increase in cis-DCP uptake. Conclusions-The application of cis-DCP in the potato growing industry can b e performed at exposure concentrations below the Dutch OEL of 5 mg/m(3) if the working days are limited to 8 hours. An injector equipped with either k ind of antidrip system which is in good working order, as well as the consi stent use of personal protection in accordance with the statutory direction s of use, may ensure exposure concentrations below the Dutch GEL.