Mariana Finkler

This study aimed to report the effects of chronic exposure of zebrafish exposed to environmentally relevant concentrations of 0.5, 2.4, and 5.0 mg L⁻¹ iron (Fe) and 0.2, 0.4, and 2.0 mg L⁻¹ aluminum (Al). We also evaluated the reversal and generational transposition (F1) of possible histopathological, behavioral, and genotoxic changes in the species. Locomotion changes that may have been caused by the increase in the number of apoptotic cells and in the telencephalic mitochondrial activity were observed especially after the 30 days exposure to Al and persisted after recovery (30 days). We also observed histopathological changes, such as an increase in the number of intestinal goblet cells, even after the recovery period in these animals. Our results also showed that the Fe concentrations used were insufficient to cause genotoxicity, behavioral and intestinal epithelium changes. The adult offspring (F1) of animals exposed to Al showed changes in locomotion and in the amount of goblet cells, demonstrating that even in low concentrations this pollutant can harm subsequent generations in the aquatic biota. Animals demonstrate, in general, greater tolerance to Fe which may be related to the physiological demand of this metal by the body. Even so, all concentrations of both metals that caused some change in the species represent Brazilian environmental occurrences or Brazilian legislation. It highlights the need for updating the guidelines and constant monitoring of aquatic environments, since even in the face of a hypothetical decontamination of the environment, some changes could persist and affect different trophic levels.

The aim of this study was to monitor the water quality of Luiz Rau stream, through physicochemical parameters, environmental characteristics of the site, and genotoxicity test in Allium cepa. Four water samples from Luiz Rau stream were collected once a week for one month and some physicochemical parameters were verified. The environmental characteristics were performed by the Quick Assessment Protocol (QAP) and evaluated at the sampling site. For the genotoxicity assay, the Allium cepa test was utilized. In relation to the water physicochemical parameters, low levels of dissolved oxygen (DO) and high levels of ammonia, and phosphorus were obtained, which demonstrates the poor quality of the stream. The QAP results identified the stream as impacted. The mitotic index parameter was altered in the seed exposed to raw water samples in the third and fourth sample collection, demonstrating cell cycle reduction and proliferation respectively; witch can be associated with the presence of contaminated effluents in the water. In relation to the genotoxicity, the micronuclei were increased in seeds exposed to four raw samples in comparison to the control group. Therefore, the results obtained can characterize the Luiz Rau stream as impacted, mostly by anthropic actions, corroborating with other publications.