Arsenic Transfer from As-Rich Sediments to River Water in the Presence of Biofilms

作者：Martina Prieto Diego; Martin Linares Veronica; Pineiro Veronica; Teresa Barral Maria

来源：Journal of Chemistry, 2016, 2016: 6092047.

DOI：10.1155/2016/6092047

The influence of epipsammic biofilms on As release from river sediments was evaluated in a microcosm experiment where biofilms were grown on sediments containing 106 mg kg(-1) As, collected in the Anllons River, and compared with control systems without biofilms. The As transfer to the water column was low (<0.11% of total As in the sediment) and was further reduced by 64% in the presence of biofilms. As-V was the predominant species in the overlying water in both systems. As-III concentration was higher (up to 12% of total dissolved As) in the control systems than in the systems with biofilms, where this species was almost absent. This fact is of toxicological relevance due to the usually higher mobility and toxicity of the reduced As-III species. Control systems exhibited higher As mobility in water, in sulphate solution, and in weak acid medium and higher bioavailability in diffusive gradient in thin films (DGT) devices. Arsenic retained by the biofihn was equally distributed between extracellular and intracellular compartments. Inside the cells, significant concentrations of As-III, monomethylarsonic acid (MMA(V)), and dimethylarsinic acid (DMA(V)) were detected, suggesting that active methylation (detoxification) processes are occurring in the intracellular compartment.

• 出版日期2016