Department of Biology, Ecology and Earth Sciences (DiBEST) - University of Calabria, P. Bucci street, cubo 15b, Arcavacata di Rende (CS), 87036, Italy.
Institute on Membrane Technology (ITM-CNR), P. Bucci street, cubo 17/C, Arcavacata di Rende (CS), 87036, Italy.
J Environ Manage. 2022 Jan 1;301:113796. doi: 10.1016/j.jenvman.2021.113796. Epub 2021 Oct 7.
Arsenic (As) is one of the most investigated elements worldwide due to its negative impact on the natural system. Its geochemical behavior depends on several geogenic processes, which can cause hazardous enrichment into natural waters, even in remote areas, far from anthropogenic sources. In this work the arsenic pollution issue has been addressed by studying water-rock interaction processes and applying reaction path modelling as a tool to understand the rock-to-water release of As and the fate of this natural pollutant in crystalline aquifers. In-depth geochemical characterization of several water samples discharging from crystalline aquifers was performed. The obtained data were used to fix the boundary conditions and validate the modelling outcomes. The performed modelling allowed to reconstruct the water-rock interaction processes which occur (i) in shallow and relatively shallow crystalline aquifers in which no As anomalies were observed and (ii) in As-rich areas, coupling reaction path modelling of granite dissolution with adsorption of dissolved As onto precipitating crystalline and amorphous Fe(III)-oxyhydroxides given the widespread presence of these phases in the studied environment. The results of the geochemical modelling are in agreement with the analytical data and reproduce them satisfactorily. The performed geochemical modelling is of high environmental significance because it is a flexible and powerful tool that correctly defines the water-rock interaction processes occurring in crystalline aquifers, providing valuable data to improve the knowledge on As behavior, not only in the study area, but also in similar geological settings worldwide. Therefore, the present research has broad future perspectives in the environmental field.
砷（As）是全球研究最多的元素之一，因为它对自然系统有负面影响。其地球化学行为取决于几种地球化学过程，这些过程可能导致有害的自然水源富集会即使在远离人为来源的偏远地区。在这项工作中，通过研究水-岩相互作用过程并应用反应路径建模作为理解砷从岩石到水的释放以及这种天然污染物在结晶含水层中命运的工具，解决了砷污染问题。对从结晶含水层中排出的多个水样进行了深入的地球化学特征描述。获得的数据用于确定边界条件并验证建模结果。所进行的建模允许重建发生的水-岩相互作用过程：(i) 在未观察到砷异常的浅层和相对浅层的结晶含水层中，以及 (ii) 在富含砷的地区，将花岗岩溶解的反应路径建模与溶解的砷在沉淀的结晶和无定形 Fe(III)-氢氧化物上的吸附相结合，因为这些相在研究环境中广泛存在。地球化学建模的结果与分析数据一致，并令人满意地再现了它们。所进行的地球化学建模具有很高的环境意义，因为它是一种灵活且强大的工具，可以正确定义在结晶含水层中发生的水-岩相互作用过程，为改善砷行为的知识提供有价值的数据，不仅在研究区域，而且在全球类似的地质环境中也是如此。因此，本研究在环境领域具有广阔的未来前景。
