Martín-Torre M Camino, Payán M Cruz, Verbinnen Bram, Coz Alberto, Ruiz Gema, Vandecasteele Carlo, Viguri Javier R
Department of Chemistry and Process & Resources Engineering, ETSIIT, University of Cantabria, Avda. de Los Castros s/n, 39005, Santander, Cantabria, Spain,
Arch Environ Contam Toxicol. 2015 Apr;68(3):577-87. doi: 10.1007/s00244-015-0133-z. Epub 2015 Feb 14.
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.
采用改进的CEN/TS 14429 pH依赖性浸出试验，研究了河口沉积物因pH值变化而导致的污染物释放情况。该试验使用去离子水和海水作为浸出液，在pH值0 - 14范围内进行。由于全球酸化、碳捕获与封存技术中的二氧化碳（CO₂）泄漏以及海水中的意外化学品泄漏，实验条件模拟了海洋环境的不同情况。以海水作为浸出液的浸出试验结果显示出更好的中和能力，与使用去离子水时相比，金属浸出浓度略低。受污染的沉积物显示出较低的碱中和能力（去离子水的BNCpH 12 = -0.44 eq/kg，海水的BNCpH 12 = -1.38 eq/kg），但使用去离子水（ANCpH 4 = 3.58 eq/kg）和海水（ANCpH 4 = 3.97 eq/kg）时具有较高的酸中和能力。利用Visual MINTEQ地球化学软件对实验结果进行建模，以预测使用两种浸出液时沉积物中的金属释放情况。对所有研究元素均应用了铁和铝（氢）氧化物的表面吸附。分别通过NICA - Donnan模型和斯德哥尔摩腐殖酸模型考虑铅和铜与金属有机物质的结合，改进了先前对金属释放的预测。由于建模曲线与实验值相符，因此可用于海水酸化的环境影响评估。
