title: Metal release from contaminated estuarine sediment under pH changes in the marine environment.
abstract: The contaminant release from estuarine sediment due to pH changes was investigated using a modified CEN/TS 14429 pH-dependence leaching test. The test is performed in the range of pH values of 0-14 using deionised water and seawater as leaching solutions. The experimental conditions mimic different circumstances of the marine environment due to the global acidification, carbon dioxide (CO2) leakages from carbon capture and sequestration technologies, and accidental chemical spills in seawater. Leaching test results using seawater as leaching solution show a better neutralisation capacity giving slightly lower metal leaching concentrations than when using deionised water. The contaminated sediment shows a low base-neutralisation capacity (BNCpH 12 = -0.44 eq/kg for deionised water and BNCpH 12 = -1.38 eq/kg for seawater) but a high acid-neutralisation capacity when using deionised water (ANCpH 4 = 3.58 eq/kg) and seawater (ANCpH 4 = 3.97 eq/kg). Experimental results are modelled with the Visual MINTEQ geochemical software to predict metal release from sediment using both leaching liquids. Surface adsorption to iron- and aluminium-(hydr)oxides was applied for all studied elements. The consideration of the metal-organic matter binding through the NICA-Donnan model and Stockholm Humic Model for lead and copper, respectively, improves the former metal release prediction. Modelled curves can be useful for the environmental impact assessment of seawater acidification due to its match with the experimental values.
authors: Department of Chemistry and Process & Resources Engineering, ETSIIT, University of Cantabria, Avda. de Los Castros s/n, 39005, Santander, Cantabria, Spain, martinmc@unican.es.
authors: M Camino
authors: MC
authors: Martín-Torre
authors: M Cruz
authors: MC
authors: Payán
authors: Bram
authors: B
authors: Verbinnen
authors: Alberto
authors: A
authors: Coz
authors: Gema
authors: G
authors: Ruiz
authors: Carlo
authors: C
authors: Vandecasteele
authors: Javier R
authors: JR
authors: Viguri
mesh_terms: D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000032:analysis*; D008956:Models, Chemical; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical