Análise qualitativa de pesticidas organoclorados em amostras de água do rio dos elefantes na zona da barragem de Massingir

Abstract

Human activities change the quality of water resources. Among these changes stand out pesticides, whose presence in waters is a source of pollution and toxicity to aquatic life, offering risks to the population and representing a great public health problem. Organochlorine pesticides, although most are banned, are still found in the environment due to its great physical-chemical stability. In the present work, the degree of contamination of the waters of the Elephants River was evaluated. in the area of ​​Massingir Dam for pesticides, since until now no systematic study had been done on organic pollutants in this area. 16 samples of river water, surface water and deep water were collected in the December 2013 and maintained in accordance with the standards described by the methods 619 and 622 of the EPA. First, the thin layer chromatography technique was applied, given its low cost and easy availability for chromatographic analysis. However, the thin layer chromatography failed to show the presence of total pesticides organochlorines, probably because their presence was below the limit of method detection. This fact reinforced the interest in studying new methodologies for determination of pesticides, ultimately culminating in the development of the silver nanoparticle method, which proved to be adequate for the determination of atrazine in water samples with detection limits and quantification of 1.84 mg / L and 5.57 mg / L, respectively. The attempt to determine the hexachlorobenzene using the same method, was unsuccessful, but it is assumed that the method is able to determine other organochlorine pesticides, as was the case with atrazine.