Ana Paula de Oliveira Schmitz

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.

The excessive application of agrochemicals has resulted in significant workplace exposure for agriculturists and environmental interaction for the general public, particularly in communities adjacent to agricultural zones. Such exposure is associated with detrimental health effects, including mutagenic and cytotoxic impacts. Agrochemical contamination frequently occurs through water, especially in rural villages where conventional water treatment systems are not designed to address these specific contaminants. The efficacy of activated carbon was investigated in this study as an adsorbent for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from contaminated water. The concentration of 2,4-D in water samples was quantified using ultravioletvisible (UV-Vis) spectroscopy at a wavelength of 283 nm. Preliminary adsorption experiments identified pH 2 as the optimal condition for 2,4-D uptake. The adsorption kinetics were best described by the Elovich model, with an equilibrium time of 480 minutes. Equilibrium studies revealed that three isotherm models-Redlich-Peterson, Temkin, and Toth-effectively represented the experimental data, with a maximum adsorption capacity of 252.8 mg/g. The findings underscore the potential of activated carbon as a cost-effective and straightforward treatment method for the removal of 2,4-D from drinking water, particularly in rural areas lacking access to advanced water treatment infrastructure.

The Campos de Palmas Wildlife Refuge (RVS-CP) is a full protection conservation unit (CU) formed by private properties. The present study aimed to use the bioindicators Allium cepa L. (cytotoxicity and mutagenicity tests) and Eisenia fetida (avoidance test) to assess the quality of surface water of the Chopim River within the RVS-CP area and its surroundings during the four seasons of the year. To do so, water samples were collected at five points, four inside the RVS-CP area and a fifth point outside thereof. Samples from all sampling points had cytotoxic effect on A. cepa in at least one season of the year. Such a finding may be related to inadequate management practices (without land-use control) in the areas surrounding the sampling points such as forestry, native fields, pastures, agriculture, and housing areas. As for the animal bioindicator (E. fetida), only points 1 (in the winter) and 5 (in the autumn) were toxic. Concerning mutagenicity, points 1 and 4 (in the spring), 1 and 2 (in the summer), and 3 (in the autumn) showed mutagenic effect on A. cepa meristematic cells, therefore only within the RVS-CP area. Overall, these results show that biomonitoring can be an ally of the residents of the RVS-CP area in controlling management practices, aiming to bring together economic support and conservation of resources, especially water.

Animals have a long history of assessing ecosystem responses to environmental disturbances, and amphibians stand out for presenting themselves as good animal model and bioindicators of environmental quality. The main purpose of the present work was to investigate the cellular effects of contamination of waters of the Marrecas River, located in the southwest of the state of Paraná, Brazil. Therefore, the objective of the present study was to investigate and monitor the cytotoxic and mutagenic effect, with bullfrog tadpoles, and to discuss these effects with land use along this hydrographic basin. Mutagenic effects were determined by micronucleus assay, and cytotoxicity by other nuclear changes, such as segmented cells, binucleated cells, cells with buds and reniform cells. Water samples were obtained at nine sites along the Marrecas River, covering areas with rural and urban hydrological contribution. For each site, four samples were collected, along the years 2017 and 2018, encompassing the four seasons (summer, autumn, winter, and spring). The results showed mutagenic and cytotoxic effect in four sampling sites, and only cytotoxic effect in other four sites. These effects may be due, possibly, to the use of different agrochemicals across the hydrographic basin region, which have predominant hydrological contributions from crops. Data of this study indicate the presence of cytotoxic and mutagenic contaminants in the waters of the Marrecas River, which can generate environmental problems on the river fauna/flora, and can also affect the local population health.