Combining ultrafiltration and diffusive gradients in thin films techniques for speciation/fractionation of Cu and Zn in cytosol of liver of Nile tilapia (Oreochromis niloticus).

This work aims to evaluate the size and lability of Cu and Zn bound to proteins in the cytosol of fish liver of Oreochromis niloticus by employing solid-phase extraction (SPE), diffusive gradients in thin films (DGT), and ultrafiltration (UF). SPE was carried out using Chelex-100. DGT containing Chelex-100 as binding agent was employed.

A new approach to improve the accuracy of DGT (Diffusive Gradients in Thin-films) measurements in monitoring wells.

The Diffusive Gradients in Thin-films (DGT) technique represents an ideal tool for monitoring water quality of inorganic species in systems with a high flow such as rivers, streams, lakes and seas. However, in low-flow systems (non-turbulent waters), the influence of a diffusive boundary layer (DBL) formed on the surface of the DGT device has been observed, which can lead to erroneous measurements by DGT. Therefore, the use of DGT in wells for groundwater monitoring is still very limited until now.

Lability and bioavailability of Co, Fe, Pb, U and Zn in a uranium mining restoration site using DGT and phytoscreening.

Mine restoration is a long and ongoing process, requiring careful management, which must be informed by site-specific, geochemical risk assessment. Paired topsoil and tree core samples from 4 sites within the uranium mining complex of INB Caldas in Minas Gerais (Brazil) were collected. Soil samples were analysed for their total content of Co, Fe, Pb, U and Zn by XRF, and subsequently, the potential environmental bioavailability of these metals were investigated by DGT and pore water analysis.

Dynamics of hydrocarbon mineralization characterized by isotopic analysis at a jet-fuel-contaminated site in subtropical climate.

Release of benzene, toluene, ethylbenzene, and xylene (BTEX) as components of the light non-aqueous phase liquids (LNAPL) contaminates soil and groundwater. Assessing the mechanisms of degradation and mineralization of BTEX in groundwater helps understand the migration of the dissolved plume, enabling the reduction of risks to humans. Here, we studied the fate of ethylbezene, m,p-xylenes and o-xylenes and the accompanying formation of methane in a Cenozoic lateritic aquifer in Brazil by compound-specific carbon stable isotope analysis (CSIA), to gain insights into the complex dynamics of release and biodegradation of BTEX in the LNAPL source zone.

LNAPL saturation derived from laser induced fluorescence method.

Light non-aqueous-phase liquid (LNAPL) spills are a widespread source of contamination in shallow aquifers. Owing to their human health risks, remediation actions should be undertaken to recover the contaminants from the subsurface. However, traditional investigation techniques do not assess the actual volume of residual hydrocarbon in the pore space, hindering the effectiveness of remediation predictions.

Controls over spatial and seasonal variations on isotopic composition of the precipitation along the central and eastern portion of Brazil.

Based on Global Network Isotopes in Precipitation (GNIP) isotopic data set, a review of the spatial and temporal variability of δO and δH in precipitation was conducted throughout central and eastern Brazil, indicating that dynamic interactions between Intertropical and South Atlantic Convergence Zones, Amazon rainforest, and Atlantic Ocean determine the variations on the isotopic composition of precipitation over this area. Despite the seasonality and latitude effects observed, a fair correlation with precipitation amount was found. In addition, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) air mass back trajectories were used to quantify the factors controlling daily variability in stable isotopes in precipitation.

Field data and numerical simulation of btex concentration trends under water table fluctuations: Example of a jet fuel-contaminated site in Brazil.

Mass transfer of light non-aqueous phase liquids (LNAPLs) trapped in porous media is a complex phenomenon. Water table fluctuations have been identified as responsible for generating significant variations in the concentration of dissolved hydrocarbons. Based on field evidence, this work presents a conceptual model and a numerical solution for mass transfer from entrapped LNAPL to groundwater controlled by both LNAPL saturation and seasonal water table fluctuations within the LNAPL smear zone.