Geochemical evaluation of bottom sediments affected by historic mining and the rupture of the Fundão dam, Brazil.

The rupture of the Fundão dam released about 39 million m3 of tailings into the Rio Doce/Brazil. The sediment load increase in the affected rivers has become a concern. As such, this article provides recent information about the region. In addition, based on past studies in the region, it shows the magnitude and dynamics of the environmental impacts caused by the rupture of the dam on the bottom sediments. Sediment samples in different seasonal periods were collected at eleven sampling stations located along the Gualaxo do Norte River, the first tributary of the Rio Doce affected by the environmental disaster. These sediments underwent physical, chemical, and granulometric analyses for their organic, metal, and semimetal content. The contamination factor and the enrichment factor of the samples also were calculated. To evaluate the anthropogenic contributions to sediment metal concentrations, reference values (regional background values) for the Gualaxo do Norte River were used. The results indicate that, in the sampling stations not affected by the disaster, the concentrations of the metals and semimetals reflect the geology of the Quadrilátero Ferrífero. However, in the area affected by the environmental disaster, there were changes in the chemical and physical properties of the bottom sediment, mainly in the concentrations of iron, organic matter, and fine sediment fractions. This was reflected in the contamination factors and enrichment factors calculated for the sediments of the sampling stations. Iron and manganese concentrations in sediments are much higher than other rivers in the world that are unaffected by mining activities. The observed changes in the bottom sediments of the river suggest a need for constant monitoring of the iron because the iron oxide minerals present in silt and clay have a high adsorption capacity. In the long term, these factors may contribute to the decrease of the quality of these sediments and consequently of the waters and biota present in these environments.

Tropidurus torquatus (Squamata: Tropiduridae) as a bioindicator of heavy metal (aluminum and zinc) pollution in Vila Velha, Brazil.

Urbanization is responsible for numerous environmental changes including pollution. Information on the susceptibility of reptiles to environmental contaminants is relatively scarce. Tropidurus torquatus represents a potential bioindicator of heavy metal pollution. Levels of heavy metals in tissues from T. torquatus depend on bioavailability and vary among different populations. The aim of this study was to determine the heavy metal concentration in liver and fat tissue of T. torquatus from three distinct populations in the state of Espírito Santo, Brazil. The study areas included coastal rocky outcrops, dunes, and mountain rocky outcrops; each area had a different climate, vegetation, and level of anthropogenic influence. Fifty-one individuals were captured. Biometrics and sexes were determined, and stomach contents were identified. The tissue samples were digested with nitric acid and analyzed via inductively coupled plasma optical emission spectrometry (ICP-OES) for aluminum (Al), arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), strontium (Sr), titanium (Ti), vanadium (V), and zinc (Zn) contents. The concentration of zinc in Tropidurus torquatus was higher in liver than in fat tissue (432 ± 1380 mg kg-1), and that of aluminum was higher in fat tissue (765 ± 1455 mg.kg-1). The animals' diet may be related to heavy metal contamination. The study suggests that T. torquatus could be used for soil biomonitoring with liver as a bioindicator for aluminum contamination and fat tissue as a bioindicator for zinc contamination. Graphical abstract ᅟ.

Evaluation of matrix effect on the determination of rare earth elements and As, Bi, Cd, Pb, Se and In in honey and pollen of native Brazilian bees (Tetragonisca angustula - Jataí) by Q-ICP-MS.

Bees are considered the main pollinators in natural and agricultural environments. Chemical elements from honey and pollen have been used for monitoring the environment, the health of bees and the quality of their products. Nevertheless, there are not many studies on honey and pollen of native Brazilian bees. The goal of this work was to determine important chemical elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Lu and Yb) along with As, Bi, Cd, Pb, Se and In, in honey and pollen of native Brazilian bees, assessing analytical interferences from the matrix. A proposed analytical method was developed for these elements by quadrupole ICP-MS. Matrix effect was verified in honey matrix in the quantification of As, Bi and Dy; and in pollen matrix for Bi, Cd, Ce, Gd, La, Pb and Sc. The quality of the method was considered satisfactory taking into consideration the recovery rate of each element in the spiked solutions: honey matrix (91.6-103.9%) and pollen matrix (94.1-115.6%). The quantification limits of the method ranged between 0.00041 and 10.3µgL-1 for honey and 0.00041-0.095µgL-1 for pollen. The results demonstrate that the method is accurate, precise and suitable.