Application of Multivariate Statistic of U, Th and Pb Concentrations and Pb Isotopic Signatures in the Assessment of Geogenic and Anthropogenic Sources in a U-Mineralized Area

Abstract

This work presents a Principal Component Analysis (PCA) study using Pbisotope signatures and U, Th and Pb concentrations from groundwater, sediments and rocks (granites and orthogneisses) of the Complex of Lagoa Real (Bahia, Brazil). This area is naturally enriched in U and Th, with the occurrence of Pb derived from the radioactive decay of the elements (238 U, 235 U and 232 Th) in the form of their stable isotopes 206 Pb, 207 Pb and 208 Pb in addition to the natural isotope 204 Pb. Sampling was carried out in the rainy season (December to January) and the points were selected according to regional hydrology and geology. Thirty samples were analyzed: 12 of groundwater (AP) and 18 of sediments (S). The results show that the use of isotopic ratios allows discrimination between geogenic and anthropogenic samples. This information is not obtained using only the analysis of concentration data. Statistically, the isotopic data of Pb stand out as an efficient tool in the characterization of sources in the scenario investigated, allowing an effective environmental monitoring and a better management of the mining activities.

Using Si, Al and Fe as Tracers for Source Apportionment of Air Pollutants in Lake Baikal Snowpack

“…Stable isotopes of light elements are more conservative than those of PAHs; however, they also can be biased due to mixing of element sources and biological fractionation [46][47][48][49][50][51]. The most reliable results are obtained using lead isotope ratios as source tracers [52][53][54][55], as the Pb isotope ratio does not change in industrial or environmental processing, and retains its characteristic value from its source ore [56]. The disadvantage of using lead isotopes is the low Pb concentrations in most study objects (i.e., water, air, and snow).…”