Metal concentrations in the whole blood of farmers in southeast Brazil.

In this study, we measured Ni, Co, Cd, and Pb concentrations in the whole blood of farmers from southeast Brazil to address the factors influencing human exposure in this population. The factors included smoking, alcohol consumption, aging, body composition, gender, and feeding preferences, which were measured through carbon and nitrogen isotopic composition. We also calculated and compared the reference values (RVs) of the measured elements to evaluate ongoing exposure levels. We observed the influence of lifestyle habits on metal exposure; Cd levels were statistically higher in smokers, and alcohol consumption affected only Pb concentrations, with an association also observed with the frequency of alcohol ingestion. The metal levels were positively associated with both isotope values, indicating that feeding may be the dominant source of these elements in this population. We also observed the effect of endogenous sources measured through age, as increased Pb concentrations in both genders and higher Cd levels in older women, which is related to bone, kidney, and liver accumulation. The body mass index was negatively associated with Ni, Co, and Cd in women and positively in men. The negative associations may indicate that body fat may act as a reservoir for metals, reducing their availability in the blood in individuals with higher body mass and possibly influencing the assessment of exposure levels. The evaluated population presented elevated RVs for all elements: Ni 36, Co 3.3, Cd 16, and Pb 149 µg L-1. These values point to higher exposure in this population compared to other studies in Brazil and worldwide. These results emphasize an urgent need for monitoring programs for toxic substances in Brazil and evaluating possible health effects, given the ongoing environmental exposure associated with endogenous exposure and lifestyle habits that promote higher metal levels in this population.

Metal concentrations and biological effects from one of the largest mining disasters in the world (Brumadinho, Minas Gerais, Brazil).

The rupture of the Brumadinho mining tailings dam in Brazil is considered one of the largest mining disasters in the world, resulting in 244 deaths and 26 missing people, in addition to the environmental consequences. The present study aims to evaluate the concentrations of multiple elements and the biological effects on water and sediments of the Paraopeba River after the Brumadinho Dam rupture. The tailings are formed by fine particulate material with large amounts of Fe, Al, Mn, Ti, rare earth metals and toxic metals. In the water, the levels of Fe, Al, Mn, Zn, Cu, Pb, Cd and U were higher than those allowed by Brazilian legislation. In the sediments, Cr, Ni, Cu and Cd levels were higher than the established sediment quality guidelines (TEL-NOAA). The differences in metal concentrations in the water and sediments between the upstream and downstream sides of the dam illustrate the effect of the tailings in the Paraopeba River. Toxicological tests demonstrated that the water and sediments were toxic to different trophic levels, from algae to microcrustaceans and fish. The fish exposed to water and sediments containing mine ore also accumulated metals in muscle tissue. This evaluation emphasizes the necessity of long-term monitoring in the affected area.

Comparative metal accumulation and toxicogenetic damage induction in three neotropical fish species with distinct foraging habits and feeding preferences.

Environmental pollutants affect fish species differently because their routes of exposure make them more critical to a specific group regarding foraging habits or food preferences. However, the association between local problems and environmental conditions makes a particular species more suitable for use in monitoring programs. Thus, this study compared muscle accumulation of metals (Al, Ba, Cr, Cu, Fe, Mn, Ti and Zn) and toxicogenetic damage to three neotropical species from the Itapemirim River Basin (Brazil) with distinct foraging habits and feeding preferences: Geophagus brasiliensis (benthopelagic - omnivorous); Harttia sp. (benthic - detritivorous); and Leporinus copellandii (pelagic - omnivorous). There was seasonal influence on muscle metal concentrations: Ba and Mn concentrations in G. brasiliensis, Cr in Harttia sp. and Zn, Al and Fe in L. copellandii increased during the rainy season. G. brasiliensis was the most sensitive species, since it had a statistically higher prevalence of erythrocytic nuclear abnormalities, which was influenced by seasonality. This result might be an effect of its benthopelagic habits, which favors contact with a larger group of contaminants due to its interaction with both water column and sediment. The present study showed the differential sensitivity of fish species and that the combination of chemical analysis of pollutants with evaluation of toxicogenetic responses helps to choose the best species for field studies.

Severe impacts of the Brumadinho dam failure (Minas Gerais, Brazil) on the water quality of the Paraopeba River

On 25 January 2019, Córrego do Feijão's tailing dam at Brumadinho city (Minas Gerais, Brazil) breached, leaving over 250 people dead. At least 12 million cubic meters of ore tailing were spread into Paraopeba River and the surrounding area. To evaluate the short-term impacts of the Brumadinho dam rupture on the environment, we performed biogeochemical, microbiological and ecotoxicological analyses across 464 km of the Paraopeba River in the week following the disaster (1 February 2019) and four months latter (27–29 May 2019). Immediately after the disaster, the water turbidity was 3000 NTU, 30 times greater than the standard recommended by the Brazilian Resolution for Water Quality (CONAMA 357). Up to a 60-fold increase in iron tolerant microbial colony forming unities was observed up to 115 km downstream of the dam failure in May 2019 (compared with February 2019), suggesting changes in microbial metabolic profiles. In the second sampling (May 2019), the ecotoxicological analyses indicate higher zebrafish embryo mortality (up to ~85% embryo mortality) rates in Retiro Baixo (304 km from dam failure location). However, increased zebrafish mortality in Retiro Baixo and Três Marias reservoirs may not be related exclusively to the dam failure. The causal nexus of mortality may be associated with other factors (e.g. local sewage pollution). Our study suggests that independent monitoring programs are needed to quantify the extent of potential impacts caused by the anthropogenic use of the river and to promote the recovery of the impacted area.

Autophagy, apoptosis and organelle features during cell exposure to cadmium.

Cadmium (Cd) induces several effects in different tissues, but our knowledge of the toxic effects on organelles is insufficient. To observe the progression of Cd effects on organelle structure and function, HuH-7 cells (human hepatic carcinoma cell line) were exposed to CdCl2 in increasing concentrations (1 microM - 20 microM) and exposure times (2 h - 24 h). During Cd treatment, the cells exhibited a progressive decrease in viability that was both time- and dose-dependent. Cd treated cells displayed progressive morphological changes that included cytoplasm retraction and nuclear condensation preceding a total loss of cell adhesion. Treatment with 10 microM for 12 h led to irreversible damages. Before these drastic and irreparable damages, treated cells (5 microM for 12 h) presented a progressive loss of mitochondrial function and cytoplasm acidification as well as dysfunction and disorganization of microfilaments and endoplasmic reticulum. These damages led to the induction of apoptotic events and an increase in autophagic bodies in the cytoplasm. These results revealed that Cd affects multiple intra-cellular targets that induce alterations in the mitochondria, cytoskeleton, endoplasmic reticulum and acidic compartments, ultimately culminating in cell death via apoptotic and autophagic pathways.

Autophagy, apoptosis and organelle features during cell exposure to cadmium. / Autophagy, apoptosis and organelle features during cell exposure to cadmium.

Cadmium (Cd) induces several effects in different tissues, but our knowledge of the toxic effects on organelles is insufficient. To observe the progression of Cd effects on organelle structure and function, HuH-7 cells (human hepatic carcinoma cell line) were exposed to CdCl2 in increasing concentrations (1 microM - 20 microM) and exposure times (2 h - 24 h). During Cd treatment, the cells exhibited a progressive decrease in viability that was both time- and dose-dependent. Cd treated cells displayed progressive morphological changes that included cytoplasm retraction and nuclear condensation preceding a total loss of cell adhesion. Treatment with 10 microM for 12 h led to irreversible damages. Before these drastic and irreparable damages, treated cells (5 microM for 12 h) presented a progressive loss of mitochondrial function and cytoplasm acidification as well as dysfunction and disorganization of microfilaments and endoplasmic reticulum. These damages led to the induction of apoptotic events and an increase in autophagic bodies in the cytoplasm. These results revealed that Cd affects multiple intra-cellular targets that induce alterations in the mitochondria, cytoskeleton, endoplasmic reticulum and acidic compartments, ultimately culminating in cell death via apoptotic and autophagic pathways.

Acute intraperitoneal mercury chloride contamination and distribution in liver, muscle and gill of a neotropical fish Hoplias malabaricus (BLOCK, 1794)

The present study investigated with the distribution of mercury chloride in muscle, liver and gills of Hoplias malabaricus contaminated through intraperitoneal injection (6 µg in 0.1mL of PBS) for a period of 24, 48, 72 and 96h. The liver, gill and muscle were analyzed for mercury content in an ICP/AES (Varian Liberty II) with vapor generating accessory (VGA 77). The muscle and liver tissues presented the same contamination pattern increasing concentrations in 24 h of exposure with a decrease in Hg concentration with 72 h and a new increase in Hg concentrations with 96 h of exposure. The Hg concentrations in contaminated organisms were always higher than the control although only for liver samples the difference was statistically significant. Liver samples always presented higher Hg contents when compared with gill and muscle samples.