RESIDUE ANALYSIS OF ORGANOCHLORINE AND ORGANOPHOSPHORUS PESTICIDES IN URBAN LAKE SEDIMENTS

ABSTRACT The knowledge of pesticide residual concentrations in the environment is important to understand the threats to the environment and human health, especially when natural resources are used for human consumption. In this context, this study aimed to assess the potential ecological risk and respective sources of sediment contamination by organochlorine and organophosphorus pesticides. The study site was an urban lake located in Cascavel city, western Paraná state, Brazil, where the history of land use and occupation in the urban environment is typically agricultural. Surface sediment samples were collected every three months from April 2010 to June 2013 at five different collection points, totaling 65 samples. Analyses showed that contamination by organochlorine pesticides is related to agricultural activities in the past, with a low ecological risk to benthic organisms. Conversely, organophosphorus pesticides presented a recent and continuous contamination from urban activities, with a risk coefficient, especially for disulfoton, indicating a significant potential adverse effect on organisms. However, in general, the obtained results did not indicate an immediate risk to public health.