Cassiano Aparecido de Souza

The systemic toxicities and cellular responses triggered by ethylparaben were evaluated in the roots of cenoura, tomate, and pepino seeds, in the roots of cebola bulbs, and in Eisenia fetida earthworms, at 1, 10, 100, and 1000 ng.L-1. In plants, concentrations significantly altered catalase activity, ascorbate peroxidase, guaiacol peroxidase, and superoxide dismutase. In carrot (10, 100, and 1000 ng.L-1), tomato (1000 ng.L-1), and cucumber (all concentrations) caused lipid peroxidation. Oxidative radicals produced caused a delay in the progression of the cell cycle and cellular changes in the root meristems, significantly inhibiting roots growth in the plants evaluated. In earthworms, ethylparaben caused a dose-dependent pattern of aversion to the treated soil, which at 1000 ng.L-1 was 90%, characterizing high repellency with habitat loss. Earthworms had no mortality after 14 days of an acute exposure to ethylparaben. Catalase, ascorbate peroxidase, and guaiacol peroxidase were significantly inhibited at the 10 ng.L-1 concentration, and all concentrations caused lipid peroxidation, which results in tissue damage and can substantially impact the survival and ecological functions of these organisms. Therefore, recurrent contamination with ethylparaben can negatively affect soil quality, impacting crop productivity and the ecological sustainability of agricultural landscapes.

The Santo Antônio River, a surface watercourse forming part of the Brazil-Argentina border, is a tributary of the Lower Iguaçu River, region that houses the biodiverse Iguaçu National Park. This study aimed to assess its impact on the Iguaçu River’s water quality. Samples were collected at 10 points: eight along the Santo Antônio River (P1 to P8), from source to mouth, and two in the Iguaçu River, upstream (P9) and downstream (P10) of the Santo Antônio’s mouth. Physicochemical analyses revealed turbidity above the limit in P6, P7, P8, and P10 and higher than allowed biochemical oxygen demand (BOD) at all points. The hormone estriol (E3) was detected in all samples (10.50 to 30.54 μg.L⁻¹), while 17β-estradiol (E2) was detected only in P2. The herbicide 2,4-D exceeded the limits in P3, P6, P7, P8, and P9. High concentrations of aluminum and iron were found in P8, with manganese above the limit in P8 and P10. In the sediments, high concentrations of chromium, nickel, and copper were confirmed at several points. Ecotoxicological tests with Artemia salina indicated high mortality in several points. Lithobates catesbeianus and Allium cepa showed cytotoxicity and mutagenicity at multiple points, while Eisenia fetida and Lactuca sativa did not present significant toxicity. Human liver cells (HuH7.5) had proliferation in P1, P2, and P8, while P9 and P10 showed cytotoxicity. The results show that the Santo Antônio River contributed to the degradation of water quality in the Iguaçu River, especially in terms of turbidity, BOD, hormones, metals, and ecotoxicity for A. salina.