Multi-element contamination in soils from major mining areas in Northeastern of Brazil.

Mining has become one of the main factors in the global biogeochemical cycle of potentially toxic elements. Therefore, it is considered one of the anthropogenic activities with the greatest negative impact on the environment. These impacts are maximized in semiarid regions, where mining activities can lead to soil degradation and decrease in land productivity. This study aimed to assess the level of contamination in natural, urban, and agricultural soils of three important mining areas, where approximately 80,000 people live, and pollution levels have never been determined before. For this purpose, soil samples were collected around iron, uranium, and vanadium mines, as well as in the main human settlements of the region. The concentrations of 34 elements were determined by instrumental neutron analysis activation (INAA) and inductively coupled plasma optical emission spectrometry (ICP OES) techniques. Pollution indices (CF, EF, mCd, PLI, and REEP) revealed that there is a moderate to heavy level of pollution for 89% of the analyzed elements. Additionally, an extreme contamination level was observed in 78% of the samples, for at least one element. Statistical analyses were performed to identify patterns in the distribution and common sources of pollution. The results suggest that the concentrations for Al, Ba, Hf, Na, Pb, Rb, REE, Ta, Th, U, Zn, and Zr are associated with geogenic causes. However, the influence of anthropogenic sources such as agriculture and mining on the accumulation of these elements in soils should not be disregarded. In contrast, the contents of As, Br, Cd, Co, Cr, Cs, Cu, Fe, K, Mn, Ni, Sc, Ti, and V reflect the direct impact of anthropogenic sources.

Determination of various nutrients and toxic elements in different Brazilian regional diets by neutron activation analysis.

The concentration of 19 elements (As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se and Zn) was evaluated in some diets taken from different regions of Brazil by Instrumental and Radiochemical Neutron Activation Analysis. Several populations with different socio-economic living conditions and inhabiting in different regions of Brazil were studied in order to estimate and to detect the variability of the mineral and toxic element content among Brazilian populational groups. The data obtained showed a significant difference between the contents of these elements in the diets from the regions studied. The general conclusions from the data obtained in this study were: 1) regarding the daily amounts of essential elements (Ca, Cl, Co, Fe, Mn, Na, K, Fe, Se and Zn), the Santa Catarina 2 diet showed the closest values when compared to the recommended values of RDA (Recommended Dietary Allowance) and/or WHO (World Health Organization). The Santa Catarina 1(low income groups) showed the lowest when compared to the same values. 2) The intake of toxic elements (As, Br, Cd, Hg, Sb) among the diets does not seem to be a major problem when compared to PTWI (Provisional Tolerable Weekly Intake, WHO), except for Hg intakes in regions near gold mining activities, like Manaus and Mato Grosso, where the values found were near the upper limit set by WHO.

Neutron activation analysis of biological samples at the radiochemistry division of IPEN-CNEN/SP.

Neutron activation analysis is a very useful method for determination of a great number of elements in biological samples. At the Radiochemistry Division of the IPEN-CNEN/SP, this method is being extensively applied to study several materials, such as extracts from medicinal plants, human hair, snake venoms, human lungs, food-stuffs, and corn samples. Both instrumental neutron activation analysis (INAA) and radiochemical neutron activation analysis (RNAA) are used to analyze real samples, as well as biological standard reference materials to evaluate the accuracy and precision of the results.