Groundwater hydrogeochemistry used for human consumption. Lower Chubut river catchment

El objetivo de este estudio fue caracterizar la hidrogeoquímica del agua subterránea utilizada para consumo humano de la localidad de 28 de Julio (NE-Chubut). Se tomaron muestras de agua subterránea de tres pozos en junio 2017. Se determinó in situ los parámetros físicoquímicos (sonda YSI-556-MPS), y en laboratorio se midieron los elementos trazas (ET), elementos de las tierras raras (ETR), iones mayoritarios (ICP-MS), nutrientes (autoanalizador- Skalar) y radón-222 (RAD7-Durridge). Las aguas subterráneas presentaron un gradiente en profundidad desde sódico-potásicas hacia aguas cálcicas. Las concentraciones de los ET (Mn<Sr<Zn<Ba<Fe<Se<V<Al<As<Ti<Cu<Rb<Mo<Ni<Co<Cr<Pb<Cd<Sb) fueron menores a los valores máximos fijados por el Código Alimentario Argentino, con excepción del Mn y Se. Los ETR más livianos presentaron mayor concentración que los pesados. La concentración de nitrato+nitrito fue dos ordenes de magnitud mayor respecto al amonio y fosfato. El agua subterránea presentó alta actividad de Radón-222. Estos resultados se comparan con datos de agua superficial del río Chubut.Centro de Investigaciones Geológica

Geochemical study of beachrocks and hybrid carbonates deposited during the Holocene in southeastern Brazil

The data refer to the geochemical and isotopic characterization of sandstones, with carbonate cementation (beach rocks), and hybrid carbonates, formed by algal mats, in the shallow platform of the South Atlantic Ocean, Espírito Santo - Brazil. The determination of 14C activity was performed on 10 samples in Accelerator Mass Spectrometry Dating (AMS), University of California, Irvine (UCL). Sample preparation backgrounds have been subtracted based on measurements of 14C-free calcite. Radiocarbon concentrations were given as fractions of the modern standard, δ14C, and the conventional radiocarbon age followed the convention of Stuiver and Polach (1977). The 14C calibration was performed on the Radiocarbon Calibration Program* CALIB REV7.1.0, Copyright 1986-2018 (Stuiver and Reimer, 1993), with marine13.14C calibration dataset (Reimer et al., 2013). The concentrations of rare earth elements (REEs) and traces were obtained by ICP-MS (PerkinElmer Nexlon300D), after digestion according to the modified EPA Protocol 3052. The quality of data was checked by the analysis of standard reference material (PACS-2 National Research Council, Canada)

Age determination of beachrocks and hybrid carbonates deposited during the Holocene in southeastern Brazil

The data refer to the geochemical and isotopic characterization of sandstones, with carbonate cementation (beach rocks), and hybrid carbonates, formed by algal mats, in the shallow platform of the South Atlantic Ocean, Espírito Santo - Brazil. The determination of 14C activity was performed on 10 samples in Accelerator Mass Spectrometry Dating (AMS), University of California, Irvine (UCL). Sample preparation backgrounds have been subtracted based on measurements of 14C-free calcite. Radiocarbon concentrations were given as fractions of the modern standard, δ14C, and the conventional radiocarbon age followed the convention of Stuiver and Polach (1977). The 14C calibration was performed on the Radiocarbon Calibration Program* CALIB REV7.1.0, Copyright 1986-2018 (Stuiver and Reimer, 1993), with marine13.14C calibration dataset (Reimer et al., 2013). The concentrations of rare earth elements (REEs) and traces were obtained by ICP-MS (PerkinElmer Nexlon300D), after digestion according to the modified EPA Protocol 3052. The quality of data was checked by the analysis of standard reference material (PACS-2 National Research Council, Canada)

Trophic analysis of female mangrove crabs at two sites from Southeastern Brazil (Rio de Janeiro)

The mangrove crab&nbsp;Ucides cordatus&nbsp;(Linnaeus, 1763) is a burrowing crab with an important role in mangrove nutrient cycling. The species holds major socioeconomic importance, generating yield for traditional and low-income populations. Despite its ecological and economic importance, there are few experiments in Brazil applying stable isotope tools to trophic crab classification, and even fewer considering females in the reproductive period. Females have different energy demands than males; studies examining C and N can reveal details regarding the differences. Hence, the present study is the first analysis of the δ&nbsp;13C, δ&nbsp;15N, and the C/N ratio in ovigerous females of two populations from Southeastern Brazil (Caceribu River - Guanabara Bay and Gargaú mangrove - Paraiba do Sul River secondary estuary). The Caceribu mangrove is larger and is located in one of the most impacted bays in the world. In the Paraiba do Sul River region, the mangrove swamp is about ten times smaller, has a substantially lower population in the surrounding area, and is more influenced by agricultural activities. The δ&nbsp;13C analysis confirmed mangrove leaves as their main food source. The significant δ&nbsp;13C variation between the Guanabara and Paraiba do Sul estuary populations can be related to differences in food availability and nutritional value. However, the δ&nbsp;15N values can be related to the ingestion of other food items during the breeding season as well as the influence of anthropogenic mangrove degradation. At both study sites, the δ15N values were higher than those observed in other mangrove crab populations and other herbivorous species. Significant (p&nbsp;&lt; 0.05) isotopic differences were found among populations, suggesting variations in biogeochemical cycles that may be related to different environmental conditions between the sites

Residential radon exposure and seasonal variation in the countryside of southeastern Brazil

Poorly ventilated environments such as residences can accumulate radon gas to levels that are harmful to humans and thus produce a public health risk. To assess the risk from natural radiation due to indoor radon exposure, 222Rn measurements, using an alpha RAD7 detector, were conducted in Timóteo, Minas Gerais state, southeastern Brazil. Indoor radon concentrations, along with meteorological parameters, were measured every 2 h during both wet and dry seasons in 2017 and 2018. The mean concentration of indoor radon varied between 18.0 and 412.8 Bq m−3, which corresponded to an effective annual dose of 1.2 and 7.6 mSv y−1. Average radon concentrations were significantly higher during the winter dry season, and there was a strong positive correlation with humidity in both wet and dry season. Furthermore, concentrations showed an inverse correlation with atmospheric pressure, wind speed, air temperature, and solar radiation. The radon levels are generally above the limits recommended by international standards, meaning that mitigation measures are needed to improve air quality to reduce human exposure and risk. Finally, through the statistical analysis, it was possible to determine the differences and similarities between the sampling points concerning the geology of the place and the geographical location

The use of caffeine as a chemical marker of domestic wastewater contamination in surface waters: seasonal and spatial variations in Teresópolis, Brazil

Abstract This study assessed the suitability of caffeine as an indicator for surface water pollution by domestic wastewaters. Caffeine concentrations determined in samples collected in the Paquequer River, located at the city of Teresópolis, a medium-sized city in the State of Rio de Janeiro, Brazil, were compared to other conventional water quality parameters such as phosphate, nitrate and ammonium concentrations to determine whether it as an efficient indicator of anthropic pollution of an urban aquatic environment. The Paquequer River originates in a pristine area called Parque Nacional da Serra dos Órgãos (PARNASO) and it crosses the urban area of the city of Teresópolis. Water samples were collected at seven points along the river, considering the periods of rain (summer) and drought (winter) and the different uses of land. Caffeine was measured using Solid Phase Extraction (SPE) and High Performance Liquid Chromatography (HPLC). Caffeine concentrations were found in a range from 0.16 to 47.5 µg L-1. The results show a positive relation between caffeine, phosphate, nitrate and ammonium concentrations and the increase of wastewater load, suggesting that caffeine can be used as an indicator of surface water pollution by domestic wastewaters