Valutazione della genotossicità dell'imidacloprid in relazione all'attivazione metabolica ed alla composizione del prodotto commerciale

Imidacloprid is a neonicotinoid insecticide combining excellent efficacy against parasites and low toxicityfor mammalians. It is commercialised with coformulants including dimethylsulfoxide, methylpyrrolidone and mineral oil, which can modify its bioavailability and toxicological profile for human following occupational exposure. A combined in vitro approach employing comet assay and micronucleus test was used to assess the genotoxicity of imidacloprid in relation to formulation, metabolic activation and exposure level. Human peripheral blood lymphocytes from unexposed healthy volunteers were treated with imidacloprid (0.2, 2 e 20 μM) and equimolar concentrations of a commercial product, with and without addition of S9 fraction. Imidacloprid increased significantly comet score and frequency of micronuclei only at the highest dose tested. DNA damage was slightly more severe with commercial product, and was increased by metabolic activation. These results suggest that at doses <20 μM imidacloprid is not genotoxic on human lymphocytes in vitro; nonetheless, the presence of coformulants in the commercial product and occupational exposure not respectful of safety procedures may determine an increased risk for DNA fragmentation and chromosomal aberrations.