Pesticide human exposure reduction optimizing spray application technologies: λ-cyhalothrin measurements in bio- and artificial-samples

In the present work, the effectiveness of optimizing pesticide application equipment (PAE) settings using optimal volume rate adjustment and spray drift reduction technology tools has been tested to verify their effectiveness in reducing human exposure of operators and bystander populations in citrus and vineyard crops. Thus, the application of an insecticide, λ-cyhalothrin active ingredient-based, with conventional (reference) and optimized spray settings have been compared by using i) passive artificial samplers which measured soil-sedimenting, airborne spray drift and dermal deposit and ii) active artificial samplers, which measured bystander inhalation exposure and secondary pollutants. Concurrently, pesticide biomarkers levels in urine of both operators and bystanders were measured. Results from the field trials assays demonstrated that the use of the optimized PAE settings reduced by 99 % and 61 % drift ground sediments, and by 87 % and 85 % airborne sediments in citrus orchard and vineyard, respectively. Inhalation exposure was reduced by 85 % and 70 %, as well as dermal exposure up to 91 % and 71 % in citrus and vineyard, respectively. Regarding λ-cyhalothrin biomarkers in urine, no significant reductions were obtained for 3-PBA, but CFMP levels decreased by 79 % and 57 % in citrus, and 70 % and 60 % in vineyard, for operators and bystanders, respectively. This work shows the effectiveness of PAE setting optimization in reducing pesticide exposure for bystanders and operators. For the first time, a direct link between optimized PAE settings and reduced human insecticide biomarker levels has been demonstrated, emphasizing the essential role of proper PAE adjustments in minimizing pesticide use-risks.