Introduction Pesticide exposure in agricultural workers may be investigated using biomonitoring, i.e. the measurement of pesticides or their metabolites in easily accessible specimens. However, the scarce information on the fate of pesticides in the human body may impair this approach. This work aims to show the strategy developed to perform biomonitoring of the exposure to tebuconazole and penconazole, fungicides widely applied in the vineyard.

Methods Metabolites of tebuconazole and penconazole in workers urine were identified using mass spectrometry. The major metabolites were search prior, during and after the application of the fungicides, to elucidate the kinetics. Urinary metabolites were correlated with dermal exposure to verify their relationship with the external dose. The presence of the fungicides in workers hair prior and after the application season, was also investigated.

Results Hydroxy-metabolites of both tebuconazole and penconazole were identified as the major metabolites in humans; to a lesser extent, also carboxy-metabolites were found. Their concentration in urine of agricultural workers increased passing from prior to after the application sample and increased during the workweek, from the first to the last consecutive application; the sample collected in the 24 hours after the last application showed the maximum levels of metabolite. The correlation between urinary metabolites and dermal exposure showed Pearson correlation coefficient ranging from 0.3 to 0.7. The levels of conazoles in hair increased during the application season.

Discussions The outlined approach to human biomonitoring of conazole fungicides was successful. It opens the possibility to apply urinary hydroxyl- and carboxy-metabolites of tebuconazole and penconazole as short-term biomarkers of exposure. It also encourages further investigation on the measurement of pesticides in hair to assess long-term exposure.