Endocrine disrupting chemicals (EDC) are exogenous substances that can potentially mimic hormonal substances and cause adverse effects on the endocrine system of living beings. The behavior and fate of these compounds in the environment is directly related to their physical-chemical properties, which indicate great affinity for solid and organic particles and suggest an inherent mechanism of fractionation between dissolved and particulate phases of aqueous matrices. However, few studies have been considering this fact when quantifying these pollutants and their effects through bioassays. In this study, the fractionation of estrogenic substances between dissolved and particulate phases in an urban stream was investigated via estrogenic activity evaluation by the YES assay. Two fractions of suspended solids (< 0.7 µm and between 0.45 and 0.7 µm) and the dissolved phase were considered and two approaches of SPE percolations were applied. Total estradiol equivalent (E2-Eq) values were observed in the 29-65 ng L^-1 range, of which 35-62% were associated with the particulate phase. Most of the estrogenicity was associated with particles between 0.45 and 0.7 µm, whereas cytotoxicity was induced by extracts of particles greater than 0.7 µm. Results demonstrated the importance of solid fractions analysis towards the quantification of total estrogenic activity from aqueous environmental matrices and highlights the relevance of controlling fine suspended solids in sewage treatment plant effluents, regarding the control of endocrine disrupters in the environment.

The present study investigated the degradation of levonorgestrel (LNG) and gestodene (GES) through an anodic oxidation process mediated by active chlorine species. The independent variables [LNG]₀ and [GES]₀, current density (mA cm⁻²), and [NaCl]₀ (mol L⁻¹) were optimized through a response surface methodology (RSM) based on a four-level central composite design (CCD). Specific energy consumption allowed CCD-RSM analysis and optimization. The decay of progestins was followed to verify the kinetics of the anodic degradation process. Chlorine monitoring showed that excess Cl⁻ concentration did not mean high hormones removal, as well as the excess of current density. Central point conditions ([NaCl]₀ = 0.07 mol L⁻¹, j = 32.5 mA cm⁻², [LNG]₀, and [GES]₀ 1.0 mg L⁻¹) proved to be the best operational option. The performance with real pharmaceutical wastewater confirmed model optimization (2.2 ± 0.2 kWh g⁻¹, with removals of 83.1 ± 0.9% and 75.1 ± 2.8% for LNG and GES, respectively). The selected condition was used for estrogenic activity and acute toxicity assays. The first allowed the identification of the initial estrogenic activity for the mixture of LNG and GES (924 E2-EQ ng L⁻¹). Additionally, the electrochemical process could decrease this environmental parameter by 74.6%. The progestin mixture was classified as acute toxicity to Daphnia similis, with a toxicity unit (TU) of 2.5 100/EC50%. After electrolysis, the hormone solutions reached a fourfold increase in TU value, classified as high acute toxicity.

O Rio Guandu é um dos principais mananciais do estado do Rio de Janeiro, embora enfrente uma pressão ambiental devido a poluição associada à falta de saneamento. Efluentes domésticos e industriais aportam uma mistura de poluentes que não são completamente removidos pelos sistemas de tratamento convencionais, incluindo desreguladores endócrinos estrogênicos. Neste contexto, aplicou-se o bioensaio in vitro Yeast Estrogen Screen (YES) para avaliar a presença de micropoluentes em amostras de água superficial da bacia do Rio Guandu através de sua atividade estrogênica. Considerou-se tanto a fase dissolvida quanto o material particulado suspenso (MPS), permitindo uma avaliação abrangente da amostra. Os resultados foram comparados a estudos no Rio Guandu realizados na década anterior e tiveram sua significância ambiental interpretada segundo o valor de EBT (effect-based trigger) de 1,17 ng L-1, que indica o limiar de segurança para o ecossistema aquático avaliado com o ensaio YES. Os resultados indicam elevada atividade estrogênica, com equivalente-estradiol (EQ-E2) de até 21,5 ng L-1 no Rio Guandu. A quase totalidade das amostras excederam o valor de EBT, sugerindo possível risco ao ecossistema aquático. A fase dissolvida foi responsável pela maior fração da atividade estrogênica total e a análise comparativa indica ainda uma piora na qualidade da água no curso do Rio Guandu, com aumento da mediana de EQ-E2. Os resultados reforçam a urgência do controle da poluição na região, bem como a relevância do monitoramento ambiental abrangente, contribuindo para o entendimento da evolução da contaminação por estrogênios no Rio Guandu ao longo da última década.