Avaliação dos parâmetros físico-químicos e ecotoxicológicos das águas do Rio Marrecas e seus afluentes em diferentes vazões

Abstract

Water quality is one of the biggest global challenges, however, a large volume of waste from industrial and urban activities is still discarded, without treatment, in bodies of water. Furthermore, many rivers suffer from changes in discharge conditions, due to high or low water flow events. Therefore, the objective of the work was to evaluate the quality of the waters of the Marrecas River and its tributaries, at high and low flows, and of the water treated by the Water Treatment Station (ETA) of Francisco Beltrão-Paraná, carrying out physical-chemical and ecotoxicological tests. Collections were carried out at five points on the Marrecas River (Points 1, 2, 3, 6 and 7), at the mouth of the Lonqueador River (Point 4), at the mouth of the Urutago River (Point 5) and at a residence supplied by ETA (Point 5). Point 8), in the high flow (314 m3 s-1) and low flow (5 m3 s-1) of the Marrecas River. The physicochemical analyzes of the samples collected at high flow rates in the present study showed high values for turbidity (P1, P2, P3, P6, P7 and P8), total dissolved solids (P1, P2, P3, P4, P5, P6 and P7), agrochemical 2,4D (P3, P4, P5, P6, P7 and P8), with values above those permitted by Brazilian legislation and high values for the estrogen hormones estrone (E1) (P5),17β-estradiol (E2 ) (P1, P2, P3, P4 and P5), 17α-ethinylestradiol (EE2) (P1, P2, P3, P4, P5, P6 and P7) and estriol (E3) (P3, P5 and P7). The samples did not affect the mobility/mortality of the bioindicator Artemia salina nor did they present a cytotoxic or mutagenic effect on the meristematic cells of Allium cepa. For Eisenia fetida, P4 showed a toxic effect through the escape test, for Lithobates catesbeianus, points 5, 6 and 8 showed a mutagenic effect and P1 showed a cytotoxic effect, through the micronucleus test with the peripheral blood of these tadpoles. For the culture of human liver cells (Huh7.5) points 3, 5 and 8 alter cell divisions by the MTT test (3-(4,5-Dimethilthiazol-2-yl)-2,5-diphenyl tetrazolium bromide). Regarding sample collection at low flow rates, physical-chemical analyzes showed that only P7 continued to present turbidity and total dissolved solids values above the values required by legislation. The values of estrogen hormones continued to be high for E1 (all points), E2 (all points), EE2 (P1, P2, P3, P5, P6, P7 and P8) and E3 (P6 and P8). It was possible to detect dissolved aluminum (P7), total aluminum (P8), dissolved iron (P7), total phosphorus (P4, P6 and P7) and total manganese (P4, P5 and P7) with values above those permitted by Brazilian legislation. Ecotoxicological tests showed toxicity for A. salina (P4), E. fetida (P4), mutagenic effect for L. catesbeianus (P5 and P7), mutagenicity for A. cepa (P4) and changes in cell divisions of Huh7.5 cells (all points). In this way, it is possible to observe that the waters evaluated are altered in physical-chemical and ecotoxicological terms and that the flow of rivers affects these parameters, warning about the need for constant monitoring and protection measures for these waters.