Levels and environmental risks of rare earth elements in a gold mining area in the Amazon.

Artisanal gold (Au) mining may have increased the concentrations of rare earth elements (REEs) in the Serra Pelada mine (southeastern Amazon, Brazil), which has not been evaluated so far. The objectives of this study were to determine the concentrations of cerium (Ce), lanthanum (La), scandium (Sc), and yttrium (Y) in the surroundings of the Serra Pelada mine, as well as the environmental risks associated with these elements. Therefore, 27 samples were collected in agricultural, forest, mining, and urban areas, and submitted to chemical and particle size characterization.

Potentially toxic elements (PTEs) in soils from the surroundings of the Trans-Amazonian Highway, Brazil.

The Trans-Amazonian Highway (TAH) is located in the northern region of Brazil, comprising a border region where agricultural, mining, and logging activities are the main activities responsible for fostering economic development, in addition to large hydroelectric plants. Such activities lead to environmental contamination by potentially toxic elements (PTEs). Environmental monitoring is only possible through the determination of element contents under natural conditions.

Prediction of the distribution coefficients of metals in Amazonian soils.

Soil pollution with metals alters ecosystem structure and function, as well as poses risks to human health. In this study the distribution coefficients (Kd) were determined for Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn in 21 soils from eastern Amazonian via Freundlich adsorption isotherm. The stepwise multiple regression models were used to estimate the Kd values through the combined effect of soil attributes.

Distribution coefficients of potentially toxic elements in soils from the eastern Amazon.

The solid-solution distribution or partition coefficient (Kd) is a measure of affinity of potentially toxic elements (PTE) for soil colloids. Kd plays a key role in several models for defining PTE guideline values in soils and for assessing environmental risks, and its value depends on edaphic and climatic conditions of the sites where the soils occur. This study quantified Kd values for Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn from representative soil samples from Brazil's eastern Amazon region, which measures 1.