Assessment of Health Risk and Presence of Metals in Water and Fish Samples from Doce River, Brazil, After Fundão Dam Collapse.

The rupture of the Fundão dam released about 50 million m3 of mining tailings in the Doce river basin. To assess the potential for environmental contamination and the risks of residual exposure of the human population generated by these tailings, water and fish samples from the Doce river were collected 25 days after the accident and analyzed the physicochemical parameters of the water and levels of metals by ICP-MS, in addition to the temporal variability of the concentration of these elements through other studies. This was the first study to carry out an assessment of the health risk associated with the consumption of fish contaminated by metals from the areas affected by the disaster. The values of turbidity (5460 NTU), electrical conductivity (74.8 µS cm-1), total dissolved solids (892 mg L-1) and total suspended solids (772 mg L-1) were above the maximum limit allowed by Brazilian legislation, due to the presence of large amounts of solid materials released after the dam rupture. The analysis of metals in water samples indicated high concentrations of Al (1,906.71 µg L-1), Mn (370.32 µg L-1), Fe (8,503.50 µg L-1) and Hg (34.25 µg L-1), while for the fish samples, only As (1,033.98 µg kg-1) and Hg (herbivorous: 505.32 µg kg-1; predatory: 1,184.09 µg kg-1) presented levels above those established by Brazilian legislation. The health risk assessment showed that the estimated daily intake for Hg was higher than the reference dose, reinforcing the need for monitoring the area affected by the disaster.

Degradation of haloacetic acids with the Fenton-like and analysis by GC-MS: use of bioassays for monitoring of genotoxic, mutagenic and cytotoxic effects.

In this study, a method was developed to evaluate the degradation of haloacetic acids (HAAs) in water by a heterogenous Fenton-like process catalyzed by cobalt-doped magnetite nanoparticles (Fe3 - xCoxO4), extraction of the contaminants by liquid-liquid extraction (LLE), and analysis by gas chromatography-mass spectrometry (GC-MS). The developed method was efficient in the degradation of HAAs, with the following degradation values: 63%, 62%, 30%, 39%, 37%, 50%, 84%, 41%, and 79% for monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, trichloroacetic acid, bromochloroacetic acid, dibromoacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, and tribromoacetic acid compounds, respectively. Through the application of the Allium cepa test, the cytotoxicity, genotoxicity, and mutagenicity of HAAs were evaluated. The results confirm its genotoxic and mutagenic effects on Allium cepa meristematic cells. Through this study, it was possible to verify the effectiveness of the developed method and its potential as a proposal for environmental remediation.