Organochlorine pesticides in the sediment of lacustrine environments (Lower Rio Doce Basin, ES, Brazil)

Abstract

Levels of pesticide were assessed in the sediment of deep and shallow lakes from Lower Rio Doce Basin (ES) to evaluate the levels of selected organochlorine pesticides (OCPs) in the sediment of lacustrine environments (shallow lakes x deep lakes). The catchment area of the studied lacustrine environments is characterized by multiple agricultural activities and human occupations. Sediment samples were collected monthly from October/2018 to February/2020. Total pesticides were analyzed in gas chromatography coupled to mass spectrometry (GC-MS). Five organic pesticides were in the sediments, including banned OCPs in developed countries such as DDT and PCBs. Highest values of DDT and PCBs were detected in the sediment of the deep and shallow lakes. No seasonal difference was observed in the concentration of PCOs in deep lake and shallow lake sediments, indicating that these environments present signs of persistent and long-term contamination. Despite the absence of seasonal influence, the heterogeneity of PCOs in the sediment was different between deep lakes and shallow lakes, indicating the influence of surface drainage on the concentration of these contaminants in the environments. The presence of already banned organic contaminants were detected, thus raising concerns. More studies are necessary, since these lacustrine environments are used for recreational and water supply purposes.

Keywords: pesticide; lakes; sediment; lacustrine environments; Lower Rio Doce Basin