Avaliação da qualidade de águas superficiais e de sedimentos quanto à toxicidade e atividade estrogênica

Abstract

A number of chemical compounds have been classified as endocrine disruptors, such as pesticides, chemicals used and produced by industries and natural and synthetic estrogens. The presence of these compounds in environmental matrices have increasingly raised concern in the scientific community because of their potential adverse health effects of various species, as these substances interfere with the production, release, metabolism and elimination of hormones and may also simulate the action of these ones. To determine the presence of endocrine disruptors different methodologies may be used. A major in vitro assays used to determine the estrogenic activity is the YES test (Yeast Estrogen Screen), a method developed by Routledge and Sumpter that uses the genetically modified yeast Saccharomyces cerevisiae. In this paper we analyzed the presence of estrogenic activity through the YES test, in raw and drinking water from the Guandu River, located in the state of Rio de Janeiro, Brazil, and in raw water and sediments of the Santa Lucía River, located in Uruguay. Chromatographic analyzes were also performed for samples of water from the Guandu River. Ecotoxicity tests and physico-chemical parameters were also determined. Based on the results of this study, it can be said that the YES assay proved to be an important monitoring and evaluation tool of water quality and sediments for the presence of estrogenic activity and the detection limit of the assay was 10.54 ± 3.53 ng.L-1. 75 % of the samples of the Guandu River showed estrogenic activity, and 20 % of raw water samples showed EQ- E2 higher than 1 ng.L -1. What is cause for concern, since this concentration is already responsible for adverse effects. The drinking water samples also showed estrogenicity, which indicates that the water treatment should be optimized in order to achieve the removal of micropollutants such harmful to human health and other animals. EQ- E2 values lower than 1 ng.L -1 were detected in the samples of Santa Lucía River, which does not rule out the need for attention, since the synergistic effect of these micropollutants in environmental matrices, is always worrying. In the samples subjected to high-performance liquid chromatography with fluorescence detection it was possible to detect the 17α - ethinylestradiol in 95 % of them. Ecotoxicity tests have been inefficient to predict the effects on the environment caused by this class of micropollutants. Thus, the estrogenic activity assays are best suited to evaluate the potential effects of endocrine disruptors, so their methodologies should be completely dominated and deployed as tests necessary to evaluate the effects of effluents discharged.