APPLICABILITY OF ASPECIFIC NONINVASIVE METHODS FOR BIOMONITORING OF OCCUPATIONAL EXPOSURE TO DELTAMETHRIN - PRELIMINARY-STUDY USING AN ANIMAL-MODEL

Deltamethrin (CAS registry No. 52918-63-5), a synthetic dibromo-pyreth roid insecticide is highly effective against a broad spectrum of insec ts, and is widely used on crops and in public health programs. Data on the genotoxicity and carcinogenicity of deltamethrin are rather contr oversial, depending on the genetic system or the assay used. The aim o f the present study was to analyze previously demonstrated metabolic c hanges using aspecific noninvasive methods in rats which art: potentia lly applicable for monitoring occupational exposure. Since human expos ure to pesticides occurs not only to active principles but to ail chem icals present in a commercial formulation, we tested both the pure com pound and a deltamethrin-based commercial formulation. Groups of rats were treated, i.p., consecutively for 7 days. The daily doses tested w ere 5 and 10 mg/kg body weight for pure deltamethrin, corresponding to volumes of 178.57 and 377.14 mu l/kg body weight for the commercial f ormulation (containing 2.8% deltamethrin). Urine was analyzed for muta genic metabolites, thioethers, and D-glucaric acid content. Faeces ext racts were tested for mutagenicity. Results show that DGA urinary excr etion values did not mirror the phase I enzyme induction capability of the insecticide. Results obtained for urinary thioethers do not agree completely with those obtained on the influence of deltamethrin on gl utathione S-transferase activity in rat liver. In fact, after administ ration of the deltamethrin commercial formulation, highest thioether e xcretion values were obtained during the treatment time for treated an imals, as compared to controls. The mean values (+/-SEM) of thioether excretion were 0.033 +/- 0.002 mu mole -SH/24 h for control animals, 0 .122 +/- 0.004 and 0.185 +/- 0.025 for the two treatment groups. Thenc e, thioether determination in urine samples seems to be a suitable asp ecific noninvasive method for assessing exposure to deltamethrin-based formulations, particularly those containing xylene and mesitylene as solvents, as in the tested formulation. Negative or toxic results obta ined in the urinary and faecal mutagenicity test seem to exclude the f ormation and excretion of mutagenic metabolites following treatment wi th deltamethrin.