Spatial pattern of pesticides in a Mediterranean rural area cultivated with citrus fruit: contribution of drift events and inadequate green cover to contamination of a local village

A monitoring campaign was carried out in a Mediterranean agricultural district by transplantation of thalli of the lichen Evernia prunastri to 32 stations to evaluate the distribution of pesticides, the development of drift events, the dimension of the area, and the level of exposure in the Cantinella village. Spearman correlation coefficients and PCA performed on the database stations × pesticides revealed that they were sprayed as mixtures and mostly bioaccumulated in the northern part. Spirotetramat and Hexythiazox exhibited the highest levels, consistent with the pests, being the former sprayed to contrast Tetranychus urticae, the most diffused species, and the latter used as a multi-spectrum pesticide. Based on the Calabria Region treatment schedule and covariance between pesticide spatial variation, we believe that Hexythiazox and Acetamiprid treatment has gone beyond prescribed deadline. Drift events were associated with the detection of pesticides in Cantinella and zones managed with organic agriculture criteria and to the significant correlation between the concentration patterns and wind flows. All the pesticides were detected inside Cantinella stations pointing to a potential co-exposure of the inhabitants to them. Spirotetramat concentration was 80% higher than that of the outside stations. The green-cement cover ratio was strongly inadequate for reducing atmospheric pollution, with a significant spatial variation (chi-square test) in green areas (northern side: 14%, southern side: 24%) associated with the percentage of single and total pesticide loads (northern side: 25%, southern side: 7%). Our data suggest that widespread drift, caused also by over-spraying, can damage the agricultural economy and promote pesticide inhalation by residents, especially when urban characteristics increase exposure.