Avaliação de agrotóxicos em amostras de solo e de morango de sistemas de produção agrícola convencional e agroecológico

Abstract

In the Contestado Settlement, Lapa, PR, soil samples from agroecological and conventional environments and strawberry samples from conventional environments were evaluated against the pesticides alachlor, atrazine, chlorpyrifos and trifluralin. Soil sampling was carried out at 10 points and at 3 depths, 5 in an agroecological environment and 5 in a conventional environment, with sampling frequency at 2- month intervals. Strawberry samples were collected from all 5 conventional environments. The soil was characterized for its textural, chemical and fertility parameters and the data used in the chemometric study (PCA) showed that the environments are different. The extraction, identification and quantification method was validated at the trace level. The analytes were analyzed by GC-MS/MS, the recovery values were between 83 and 113%, RSD less than 14%, LD equal to 0.01; 0.0028; 0.004 and 0.02 μg kg-1, LQ equal to 0.04; 0.008; 0.011 and 0.05 μg kg-1, for alachlor, atrazine, chlorpyrifos and trifluralin, respectively. Chlorpyrifos was identified in Conv3 and trifluralin in Agro2 and 3 and Conv2 environments. The effect of rain/rainfall on the samples was evaluated by simulation and it was found that the physicochemical properties of the compounds and the soil influence their behavior in the soil profile. The recoveries for the extraction of pesticides in strawberry were between 12.8 and 18.6%; 11.8 to 23.8%; 12.7 to 22.3% and 17.4 to 19.8%, respectively, and it is not possible to validate the method for this matrix. Therefore, it was possible to observe the occurrence of environmental contamination by pesticides between the agroecological and conventional systems.