Phytoremediation, bioaccessibility and ecotoxicological risk assessment of arsenic in a gold mining area.

The physicochemical and biological parameters of aquatic ecosystems are directly affected by mining activities, increasing the ecotoxicological risk related to exposure to contaminants and pollutants. In this study, a native and adapted floating aquatic macrophyte was used in a gold mining area as a model organism to assess the environmental risk and its potential application in bioremediation of heavy metals. The physicochemical parameters of water and sediments were evaluated, as well as the phytoremediation parameters (bioconcentration and translocation factors) of Hydrocotyle ranunculoides L. The results showed a significant bioconcentration of Cr, Pb, Cu, and Zn in the roots of the macrophyte (high BCF: As > Cu > Zn > Pb > Cr), confirming its suitability for use in rhizofiltration. Regarding arsenic bioconcentration, H. ranunculoides demonstrated a high BCF and TF > 1, indicating its phytoextraction potential, an essential requirement for plants to be used in bioremediation programs.

Using native fish in eco-genotoxic assessment of heavy metal contamination pollution arising from nearby large Brazilian rivers.

Worldwide water quality has declined progressively due to continuous pollution of aquatic resources by agrochemicals in particular heavy metals. Fish genotoxicity biomarkers are vital to identify and complement chemical parameters for determining environmental risk of adverse effects. Therefore, it was of interest to examine the eco-genotoxicity attributed to water pollution over different stream sections of Brazilian rivers by using Cichlasoma paranaense (Teleostei: Cichlidae), a neotropical freshwater cichlid fish, as a biological model. Chemical analysis of water and sediments collected from different Brazilian rivers sites demonstrated contamination by metals. Cichlasoma paranaense were collected at a reference location (a permanent water preservation area), maintained in the lab under standard conditions (controlled temperature, lighting, daily feeding, and constant aeration) and exposed to environmental samples of water and sediments. Subsequently, micronucleus (MN) and nuclear abnormalities (NA) frequencies were assessed in erythrocytes obtained from the caudal and gill regions. The highest concentrations of Cu were found in samples from river sites with forest fragmentation attributed to intensive agriculture practices. Similarly, exposure of fish to samples from agricultural areas induced significantly higher number of genotoxic effects. There was no marked difference between the tissues (tail and gill) regarding the observed frequencies of MN and NA. Thus C. paranaense fish served as a reliable model for detecting genotoxic effects, especially when water samples were collected near the discharge of agrochemicals. Evidence indicates that this method be considered for other global river sites which are also exposed to agrochemicals discharges containing Cu.

Effects of environmental protection policies on fragile areas of a watershed occupied by agriculture in the Brazilian Cerrado.

Brazil has become an antagonist in natural resource conservation policies in recent years. The Brazilian Cerrado is one of the biomes most affected by this setback due to the occupation of areas of economic interest in agriculture. Interestingly, there are projects throughout the biome that aim to encourage the preservation of natural resources, but there is uncertainty about whether these incentives have provided conservation. That is the case of the Feio River hydrographic basin, located in the Cerrado, near the city of Patrocínio, state of Minas Gerais. Indeed, the Feio River watershed has projects incentivizing the Cerrado's conservation. Thus, in this article, we aimed to explain how the advance of agriculture in fragile areas of the Feio river watershed occurs, their causes and whether protection strategies have produced satisfactory results. We used an old Environmental Fragility proposal methodwith our contributions to estimate the variations regarding nature conservation in the basin. Our findings show considerable heterogeneity in the potential fragility of the Feio's river basin. We observe that less fragile sites are used for coffee cultivation (74 and 72% of the two places), while more fragile sites are occupied by reserves (around 50% of the area) and high-impact activities such as traditional monoculture and cattle ranching (25 and 44% for the two sites). Temporally, we observed little change in use and occupation, with a slight increase in no-till farming to replace coffee and conventional cultivation. The permanent preservation areas in the basin have improved vegetation quality, while the reserve areas composed of fields show a degradation process. Considering the importance of the Feio's river basin, different incentives and inspection strategies are needed to guarantee the site's preservation and environmental restoration.