Ficorremediação do hormônio feminino 17-alfa etinilestradiol (EE2) pela microalga Chlorella vulgaris

Abstract

Domestic sewage released into the environment represents one of the most serious and chronic human and environmental health problems in Brazil. In the last decades, environmental micropollutants, such as 17-alpha ethinylestradiol (EE2), have been constantly detected in very low concentrations in surface waters. However, most current sewage treatment plants were not designed to remove micropollutants. Wastewater treatment by phycoremediation processes is attracting interest, being a low cost, good effectiveness and operational simplicity technology. In this study, the bioremediation potential of EE2 was investigated using the unicellular microalgae, Chlorella vulgaris. This microalga was exposed to 50 μgL-1 of the hormone in mineral water and the results were compared to the positive control, comprising the hormone and water and negative control, composed only by water and algae. The assays were monitored for 168 hours. Cell counts, dry biomass, chromatographic analysis and yeast estrogen screen (YES) tests were performed. Results indicate the role of algae in the degradation of the hormone, showing removal at the end of the batch test of 29.48 μgL-1, compared to 11.98 μgL-1 measured in the photodegradation control sample. The first 24 hours presented the highest algae efficiency when compared to the control, which did not present degradation in the same period. Biomass production was not affected by exposure to the hormone, being slightly higher when in contact with it. Estrogenic activity of the effluent resulting from the phycoremediation indicated a reduction of the activity in the samples extracted from the algae (sorption by the algae). However, in the free environment there were oscillations with a significant reduction verified only in the first 24 hours. C. vulgaris was shown to be promising for the study of biodegradation of environmental micropollutants.