Estrogenic activity of endocrine disruptors in the surface water of Santa Maria Madalena, Southeastern Brazil

ABSTRACT

In recent decades, the release of contaminants with endocrine disrupting capacity into the water environment has intensified. In this context, the application and improvement of efficient analytical methods are increasingly required to verify the potential impacts of these substances on the organisms exposed to them. Bioassays can be conducted with this purpose, such as the yeast estrogen screen (YES) in vitro assay, which allows the detection of estrogenic and cytotoxic compounds. This study, applying the YES assay, investigated the estrogenic activity and its potential risks to the aquatic biota of two streams in Santa Maria Madalena, Rio de Janeiro State, Southeastern Brazil. Estrogenic activity was observed only in São Domingos stream, with estradiol equivalent (EEQ) concentrations of 23 and 10.4 ng.L⁻¹ during the dry and rainy season, respectively. The potential risks of this level of estrogenic activity were evaluated by a risk assessment, which revealed a high and medium risk to the local biota in the dry and rainy seasons, respectively. Among the studied water bodies, São Domingos watershed has a bigger population density and less sewage collection and treatment comparatively to Ribeirão Santíssimo stream. The YES assay presented itself as a useful tool for spotting estrogenic endocrine disruptors, with the potential to help in expanding knowledge about water bodies and to create and enforce environmental legislation and regulations.

Keywords:
estrogenic activity; endocrine disruptors; estrogens; surface water; domestic sewage