Dialkyl phosphate metabolites of organophosphorus in applicators of agricultural pesticides in Majes – Arequipa (Peru)

BACKGROUND Organophosphorus (OPs) pesticides are the most commonly used pesticides in Peruvian agriculture. The population at risk for OPs exposure includes formulators, applicators and farmers. Majes Valley is the most important agricultural center of the Southern region of Peru. The present study was aimed to determine the knowledge about using OPs, safety practice and urinary dialkylphosphate metabolites on OP applicators in the Majes Valley, Peru. METHODS This study was based on a questionnaire which included socio-demographic characteristics, knowledge of safety practices to handling OPs, characteristics of pesticide application and use of protective measures to avoid pesticide contamination. Exposure was assessed by measuring six urinary OP metabolites (DMP, DMTP, DMDTP, DEP, DETP, and DEDTP) by gas chromatography using a single flame photometric detector. The sample consisted of 31 men and 2 women aged 20 - 65 years old. RESULTS 76% of applicators had at least one urinary dialkylphosphate metabolite above the limit of detection. The geometric mean (GM) and the geometric standard deviation (GSD) of DMP and DEP were 5.73 microg/g cr. (GSD 2.51), and 6.08 microg/g cr. (GSD 3.63), respectively. The percentage of applicators with detectable DMP, DMDTP, and DMTP in urine was 72.72%, 3.03%, and 15.15%, respectively, while the corresponding figures for DEP, DETP, and DEDTP were 48.48%, 36.36% and 15.15%, respectively. There was no significant association between the use of protection practices and the absence of urine OPs metabolites suggesting inadequate protection practices. CONCLUSION The pesticide applicators in Majes Valley have significant exposure to OP pesticides, probably due to inappropriate protective practices. Future work should evaluate possible health effects.