Four surveys of the Huelva Estuary in southwest Spain and its sources, the Tinto and the Odiel Rivers, were carried out between 1996 and 1998. The surveys investigated the impact of metalliferous mining of sulfide-rich ores in the catchment area on metal speciation, metal concentrations in a macrophyte, and phytoplankton diversity and abundance. Chemical speciation measurements in the lower Tinto Estuary showed that metals were predominantly electrochemically labile (> 99% of total dissolved Cu, Co, and Ni at 10 microM Cu, 424 nM Co, and 500 nM Ni, S = 28). Concentrations of Cu complexing ligands and free cupric ions [Cu2+] in the Gulf of Cádiz ranged between 5.3 and 38 nM and 0.2-7.9 pM, respectively, with conditional stability constants of the ligands of log K'(CuL) = 11.7-12.6. At enhanced dissolved Cu concentrations in the lower Huelva Estuary, Cu complexing ligands were saturated with Cu, resulting in nanomolar [Cu2+], which increased upstream. Metal tissue concentrations of the macrophyte Blindingia marginata were high, and a clear relationship between dissolved labile Cu and macrophyte tissue Cu concentrations was observed. A low biodiversity was observed in the Huelva system (Shannon-Wiener indices (H) typically < 0.2). Nevertheless, the maximum biomass was observed in the lower Tinto Estuary, which showed high labile metal and nutrient concentrations and a low biodiversity (H < 0.02), thereby suggesting adaptation through evolutionary processes of the phytoplankton community to the harsh conditions.
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http://dx.doi.org/10.1021/es063042h | DOI Listing |
Chemosphere
January 2025
Faculty of Agronomy and Veterinary Medicine, University of Brasília, 70910-970, Brasília, Federal District, Brazil.
Phosphorus (P) plays an essential role for plant growth, but conventional P sources used in agriculture are finite and non-renewable. As a result, there is a growing need to explore alternative P sources such as sewage sludge (SS) - a P-rich solid waste and valuable renewable resource that is often mismanaged globally. Pyrolysis is a promising technique for managing SS.
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December 2024
Soil Chemistry and Chemical Soil Quality Group, Wageningen University & Research, PO BOX 47, Wageningen 6700 AA, the Netherlands.
Binding of glyphosate (PMG) to metal (hydr)oxides controls its availability and mobility in natural waters and soils, and these minerals are often suggested for the removal of PMG from wastewaters. However, a solid mechanistic and quantitative description of the adsorption behavior and surface speciation on these surfaces is still lacking, while it is essential for understanding PMG behavior in aquatic and terrestrial systems. This study gives new insights through advanced surface complexation modeling of new and previously published adsorption data, supplemented with MO/DFT calculations of the geometry, thermochemistry and theoretical infrared (IR) spectra of the surface complexes.
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View Article and Find Full Text PDFWater Res
December 2024
Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. Electronic address:
Calcium (Ca)-enhanced organic matter (OM) fouling of nanofiltration (NF) membranes leads to reduced flux during desalination and requires frequent cleaning. Fouling mechanisms are not fully understood, which limits the development of targeted fouling control methods. This study employed synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near-edge structure (XANES) spectroscopy to quantify the spatial distribution and mass of Ca deposition as well as changes in the Ca coordination environment characteristic of specific fouling mechanisms, respectively.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
Universidad Autónoma de Santo Domingo, Facultad de Ciencias, Zona Universitaria, Distrito Nacional, Santo Domingo, Dominican Republic.
Impacts of the acid mine drainage (AMD) remediation are investigated on the largest gold mine in Latin America, located in the Dominican Republic. Geochemical analysis of suspended matter in water performed in 2022 on water bodies located downstream to the mine, namely, the Margajita River and Lake Hatillo, are compared with analyses made in 2007, before the AMD remediation. The results for the Margajita River show a strong decrease in heavy metal and metalloid concentrations in the dissolved phase for Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sb, and Pb (between 89.
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