Hydrochemistry and weathering at Pardo River basin, São Paulo State, Brazil.

This work was conducted at the Pardo River hydrographic basin, which is a federal watershed belonging to the Paranapanema River hydrographic basin (PRHB) in Brazil (São Paulo State and Paraná State). The aim was to realize an integrated hydrochemical and radiometric (U-isotopes and Po) approach, highlighting the water/soil-rock and surface water/groundwater interactions, with implications to the weathering processes occurring there. The study area has been often considered one of the best preserved/unpolluted river in São Paulo State, contributing to the water supply of several cities distributed along its banks.

Comparative analysis of gamma ray spectrometers applied to Irati Formation, Paraná basin, São Paulo State, Brazil.

This paper describes the use of gamma ray spectrometry in the study of rock samples from the Irati Formation, Paraná sedimentary basin, São Paulo State, Brazil. This technique allowed to measure the natural radiation emitted by K, as well the radionuclides belonging to the decay series of U (eU = Ra = Bi) and Th (eTh = Th = Tl) which occur in the analyzed samples. Four gamma ray spectrometers have been utilized for comparing the results obtained: a portable sodium iodide [NaI(Tl)] scintillation detector (Digidart), a handheld bismuth germanate oxide (BGO) detector and two bench NaI(Tl) crystals, differing in their geometry (Planar and Well types).

U-isotopes and weathering rates in watersheds of Araxá city, Minas Gerais State, Brazil.

This work was conducted at Araxá city, Minas Gerais State, Brazil. The aim was to characterize by different approaches weathering rates at six watersheds occurring there. The study area is well-known in the country due to economic and touristic reasons.

Sedimentation rates by the Pb chronological method in Itanhaém river watershed, southeast Brazil.

The historical variation of sedimentation rate was investigated in five cores collected from the Itanhaém watershed main rivers, the second largest coastal watershed of the São Paulo state, Brazil, using the lead-210 radioisotope as a geochronometer. The main characteristics of the rivers' waters and sediments were determined in order to support the geochronological analysis results and associate sediments with possible source areas. In this context, the fluvial waters' general classification indicated the facies sulfated or chlorinated sodium in the winter and summer seasons, except for the Branco river waters in summer, which were classified as calcium or magnesium bicarbonate.

Hydrochemical and radiometric evaluation of fresh and thermal waters from Araxá city (Minas Gerais, Brazil).

This paper reports the hydrochemistry and activity concentration of the natural radionuclides U, U, and Po for three compartments of the hydrological/hydrogeological system in Araxá city, Minas Gerais State, Brazil: 1) mineral waters from the prominent springs Dona Beja (DBS) and Andrade Júnior (AJS), occurring at Barreiro area; 2) surface waters from Barreiro area and vicinity; and 3) rainwater. According to the Rule for Mineral Waters in Brazil (Register 7841) for temperature, the DBS water is cold (< 25 °C), while AJS is hypothermal (25-33 °C). The TDS (Total Dissolved Solids) concentration of DBS is low (70 mg/L), but high in AJS (2898 mg/L).

Nitrate-dependent Uranium mobilisation in groundwater.

Nitrate is a critical substance that determines the prevailing redox conditions in groundwater, and in turn the behaviour of Uranium (U). Therefore, the excessive use of nitrate-fertiliser in agricultural catchments could exert a significant influence on U mobilisation. This is a significant issue in catchments, where groundwater resources are increasingly being exploited for drinking water production.

Tracking pollutants in selected Brazilian drainages from araxá city.

Sediments geochemical data from Araxá city, Minas Gerais State, Brazil, have provided new insights on the pollutants inputs in different drainage systems of Araxá city, Minas Gerais State, Brazil. The sediments profiles (6) provided from a lake (Grand Hotel) and streams (Sal, Areia, Fundo, and Feio). The local municipality uses some waters (Areia, Fundo, and Feio streams) in water-supply systems.

Gross alpha/beta radioactivity and radiation dose in thermal and non-thermal spas groundwaters.

Gross alpha and gross beta activities have been determined in thermal and non-thermal spas groundwaters (75) occurring at São Paulo and Minas Gerais states in Brazil as they are ingested in public places, bottled and used for bathing purposes, among other. The samples provided from springs and pumped tubular wells drilled at different aquifer systems inserted in Paraná and Southeastern Shield hydrogeological provinces. The WHO guideline reference value proposed in 2011 for the drinking water quality was never reached for the gross alpha activity (0.

Assessing mercury pollution in Amazon River tributaries using a Bayesian Network approach.

Mercury pollution of water bodies exerts significant human and ecosystem health impacts due to high toxicity. Relatively high levels of mercury have been detected in the Amazon River and its tributaries and associated lakes. The study employed a Bayesian Network approach to investigate the contribution from geogenic sources to mercury pollution of lakes in the Madeira River basin, which is the largest tributary of the Amazon River.

The application of U-isotopes to assess weathering in contrasted soil-water regime in Brazil.

This paper presents the use of U-series radionuclides U and U to evaluate the biogeochemical disequilibrium in soil cover under a contrasted soil-water regime. The approach was applied in three profiles located in distinct topographical positions, from upslope ferralitic to downslope hydromorphic domain. The U fractionation data was obtained in the samples representing the saprolite and the superficial and subsuperficial soil horizons.

Mobility indices and doses from Po and Pb activity concentrations data in Brazilian spas groundwaters.

Po and Pb activity concentrations in spas groundwaters occurring at São Paulo (SP) and Minas Gerais (MG) states, Brazil, have been reported in this paper with a dual purpose: to compare different indices for evaluating the radionuclides mobility into waters and to evaluate the drinking water quality from dose calculations. The waters (75 sampling points) are extensively used for drinking in public places, bottling and bathing purposes, among other. The samples were taken from springs and wells drilled at different aquifer systems inserted in Paraná and Southeastern Shield hydrogeological provinces.

Weathering processes and dating of soil profiles from São Paulo State, Brazil, by U-isotopes disequilibria.

This study reports the use of the U-series radionuclides U and U for dating two soil profiles. The soil horizons developed over sandstones from Tatuí and Pirambóia formations at the Paraná sedimentary basin, São Paulo State, Brazil. Chemical data in conjunction with the U/U activity ratios (AR's) of the soil horizons allowed investigating the U-isotopes mobility in the shallow oxidizing environment.

Hydrogeochemical features of surface water and groundwater contaminated with acid mine drainage (AMD) in coal mining areas: a case study in southern Brazil.

Effects of acid mine drainage (AMD) were investigated in surface waters (Laranjinha River and Ribeirão das Pedras stream) and groundwaters from a coal mining area sampled in two different seasons at Figueira city, Paraná State, Brazil. The spatial data distribution indicated that the acid effluents favor the chemical elements leaching and transport from the tailings pile into the superficial water bodies or aquifers, modifying their quality. The acid groundwaters in both sampling periods (dry: pH 2.

The dissolved uranium concentration and U/U activity ratio in groundwaters from spas of southeastern Brazil.

This paper describes the natural radioactivity due to U and U in 75 water sources from spas located in 14 municipalities in São Paulo and Minas Gerais states, Brazil. These waters are extensively utilized for drinking in public places, bottling and bathing purposes, among other uses. The water samples were taken from springs and pumped tubular wells drilled into different aquifer systems in the Paraná and Southeastern Shield hydrogeological provinces.

(210)Pb and compositional data of sediments from Rondonian lakes, Madeira River basin, Brazil.

Gold exploration has been intensive in Brazilian Amazon over the last 40 years, where the use of mercury as an amalgam has caused abnormal Hg concentrations in water bodies. Special attention has been directed to Madeira River due to fact it is a major tributary of Amazon River and that since 1986, gold exploration has been officially permitted along a 350km sector of the river. The (21)(0)Pb method has been used to date sediments taken from nine lakes situated in Madeira River basin, Rondônia State, and to verify where anthropogenic Hg might exist due to gold exploitation in Madeira River.

Uranium isotopes in groundwater occurring at Amazonas State, Brazil.

This paper reports the behavior of the dissolved U-isotopes (238)U and (234)U in groundwater providing from 15 cities in Amazonas State, Brazil. The isotope dilution technique accompanied by alpha spectrometry were utilized for acquiring the U content and (234)U/(238)U activity ratio (AR) data, 0.01-1.

Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia.

Natural, dissolved (238)U-series radionuclides (U, (226)Ra, (222)Rn) and activity ratios (A.R.s: (234)U/(238)U; (228)Ra/(226)Ra) in Continental Intercalaire (CI) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times.

(222)Rn, (220)Rn and other dissolved gases in mineral waters of southeast Brazil.

This paper describes the natural radioactivity due to (222)Rn and (220)Rn in mineral waters occurring at São Paulo and Minas Gerais states, Brazil, that are extensively used for drinking in public places, bottling and bathing purposes, among other. The measurements of these alpha-emitting radionuclides were also accompanied by the monitoring of temperature and some dissolved gases (O2, CO2 and H2S) in 75 water sources located in 14 municipalities of those states. Eight water sources yielded (220)Rn activity concentration values below the detection limit of 4 mBq/L.

Radon emissions related to the granitic Precambrian shield in southern Brazil.

The equivalent uranium (eU) activity concentration was analysed in selected granite samples at several sites in Porto Alegre, Southern Brazil, to obtain information on the radon ((222)Rn) generation by the aquifer rock matrices. Radon analyses of ground water and soil samples were also performed. Several samples exhibited a dissolved (222)Rn activity concentration exceeding the World Health Organization maximum limit of 100 Bq l(-1).

Natural radionuclides in major aquifer systems of the Paraná sedimentary basin, Brazil.

This paper describes the natural radioactivity of groundwater occurring in sedimentary (Bauru and Guarani) and fractured rock (Serra Geral) aquifer systems in the Paraná sedimentary basin, South America that is extensively used for drinking purposes, among others. The measurements of gross alpha and gross beta radioactivity as well the activity concentration of the natural dissolved radionuclides ⁴⁰K, ²³⁸U, ²³⁴U, ²²⁶Ra, ²²²Rn, ²¹⁰Po and ²¹⁰Pb were held in 80 tubular wells drilled in 21 municipalities located at São Paulo State and its border with Mato Grosso do Sul State in Brazil. Most of the gross alpha radioactivity data were below 1 mBq/L, whereas values exceeding the gross beta radioactivity detection limit of 30 mBq/L were found.

(210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil.

Activity profiles of excess (210)Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles.

Distribution of 226Ra, 232Th and 40K in soils and sugar cane crops at Corumbataí river basin, São Paulo State, Brazil.

The common use of phosphate fertilizers NPK and amendments in sugar cane crops in Brazilian agriculture may increase the (226)Ra, (232)Th and (40)K activity concentrations in soils and their availability for plants and human food chain. Thus, the main aim of this study was to evaluate the distribution of (226)Ra, (232)Th and (40)K in soils and sugar cane crops in the Corumbataí river basin, São Paulo State, Brazil. The gamma spectrometry was utilized to measure the (226)Ra, (232)Th and (40)K activity concentration in all samples.

Biodegradability of commercial and weathered diesel oils.

This work aimed to evaluate the capability of different microorganisms to degrade commercial diesel oil in comparison to a weathered diesel oil collected from the groundwater at a petrol station. Two microbiological methods were used for the biodegradability assessment: the technique based on the redox indicator 2,6 -dichlorophenol indophenol (DCPIP) and soil respirometric experiments using biometer flasks. In the former we tested the bacterial cultures Staphylococcus hominis, Kocuria palustris, Pseudomonas aeruginosa LBI, Ochrobactrum anthropi and Bacillus cereus, a commercial inoculum, consortia obtained from soil and groundwater contaminated with hydrocarbons and a consortium from an uncontaminated area.