Pesticidas em sedimentos de lago urbano

Abstract

Recognizing residual concentrations of pesticides in the environment is important to understand the threats that these compounds represent to the environment and to human health, especially when natural resources are used for human consumption. Thus, this research aimed to determine the concentrations of organochlorine and organophosphorus pesticides present in the sediments of an urban lake located in the Southern region of Brazil, as well as the potential ecological risk and possible sources of contamination according to the use and occupation of the soil through time. Samples of sediment on the surface of the lake were collected every three months, from April 2010 to June 2013, covering the four hydrological stations, in five different collection points, accounting for 65 samples. The methodology used in the extraction, identification and quantification of pesticides was the QuEChERS method. The reading was performed in Gas Chromatograph attached to a mass spectrum. The analyses indicated that organochlorine pesticide contamination dates back to past agricultural activity. Concentrations of organophosphorus pesticides indicate recent and continuous occurrence from urban activities. In general, concentrations of organochlorines rarely indicate a potential ecological risk to organisms in the benthic environment. However, for organophosphates, especially Disulfoton, the risk factor indicates a significant potential adverse effect on organisms in the environment.