Short-lived natural radionuclides as tracers in hydrogeological studies - A review.

Fundamental approaches to the study of groundwater rely on investigating the spatial and temporal distribution of stable and radioactive isotopes and other anthropogenic compounds in natural waterbodies. The most often used tracers for estimating groundwater flow paths and residence times, groundwater/surface water interaction as well as tracing chemical (contamination) sources include stable isotopes of water (δ O and δ H), radiocarbon (C; t = 5730 a), tritium (H; t = 12.43 a) as well as unreactive fluorine-containing gases (e.

Biogeochemical diversity, O-supersaturation and hot moments of GHG emissions from shallow alkaline lakes in the Pantanal of Nhecolândia, Brazil.

Nhecolândia is a vast sub-region of the Pantanal wetland in Brazil with great diversity in surface water chemistry evolving in a sodic alkaline pathway under the influence of evaporation. In this region, >15,000 shallow lakes are likely to contribute an enormous quantity of greenhouse gas to the atmosphere, but the diversity of the biogeochemical scenarios and their variability in time and space is a major challenge to estimate the regional contribution. From 4 selected alkaline lakes, we compiled measurements of the physico-chemical characteristics of water and sediments, gas fluxes in floating chambers, and sedimentation rates to illustrate this diversity.

Natural radioactivity determination in samples of Peperomia pellucida commonly used as a medicinal herb.

The concentration of (238)U, (232)Th, (230)Th, (226)Ra, (228)Ra and (210)Pb were determined in samples of Peperomia pellucida and in the surrounding soil, by alpha spectrometry and gross alpha and beta counting. The radionuclide activity concentrations ranged from 4.3 to 38 Bq kg(-1), 1.

Metal distribution in sediment cores from São Paulo State Coast, Brazil.

Ten sediment core samples with lengths ranging from 35 to 100 cm were collected in the Baixada Santista region and analyzed to determine As, Br, Co, Cr, Cs, Fe, Rb, Sb, Ta, Th, U, Zn and rare earths (Sc, Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) level concentrations using instrumental neutron activation analysis (INAA). The studied region is located in the southeastern coast of São Paulo State and is comprised of a densely urbanized area, the largest industrial complex of the country, with a predominance of petrochemical and fertilizer plants. It is also home to Brazil's most important and busiest port.

Assessment of atmospheric pollution in the vicinity of a tin and lead industry using lichen species Canoparmelia texana.

This paper examines the viability of using Canoparmelia texana lichen species as a bioindicator of air pollution by radionuclides and rare earth elements (REEs) in the vicinity of a tin and lead industry. The lichen and soil samples were analyzed for uranium, thorium and REEs by instrumental neutron activation analysis. The radionuclides (226)Ra, (228)Ra and (210)Pb were determined either by Gamma-ray spectrometry (GRS) (soils) or by radiochemical separation followed by gross alpha and beta counting using a gas flow proportional counter (lichens).