Abstract：
It is well known that aquaculture can alter the microenvironments of lakes at sediment-water interface (SWI). However, the main mechanisms underlying the effects of aquaculture activities on arsenic (As) transformations are still unclear. In this context, the present study aims to investigate the variations in the sediment As contents in Yangcheng Lake, as well as to assess its chemical transformations, release fluxes, and release mechanisms. The results showed substantial spatial differences in the dissolved As concentrations in the sediment pore water. The As release fluxes at the SWI ranged from 1.32 to 112.09 μg/L, with an average value of 33.68 μg/L. In addition, the highest As fluxes were observed in the aquaculture areas. The transformation of crystalline hydrous Fe oxide-bound As to adsorbed-As in the aquaculture lake sediments increased the ability of As release. The Partial least squares path modeling results demonstrated the great contributions of organic matter (OM) to the As transformations by influencing the sediment microbial communities and Fe/Mn minerals. The changes in the As fractionation and competing adsorption increased the dissolved As concentrations in the 0-10 mm surface sediment. Non-specifically and specifically adsorbed As were the major sources of dissolved As in the sediments. Specifically, microbial reduction of As[V] and dissolution of Fe oxides increased the dissolved As concentrations at the SWI (20 to -20 mm). The results of the current study highlight the positive enhancement effects of aquaculture on As release from sediments.
摘要：
众所周知，水产养殖可以改变沉积物-水界面（SWI）处湖泊的微环境。然而,水产养殖活动对砷（As）转化影响的主要机制尚不清楚。在这种情况下，本研究旨在研究阳澄湖沉积物中砷含量的变化，以及评估其化学转化，释放通量,和释放机制。结果表明，沉积物孔隙水中溶解的As浓度存在很大的空间差异。SWI的As释放通量范围为1.32至112.09μg/L，平均值为33.68μg/L此外,在水产养殖区观察到最高的As通量。水产养殖湖泊沉积物中结晶水合氧化铁结合砷向吸附砷的转化增加了砷的释放能力。偏最小二乘路径建模结果表明，有机物（OM）通过影响沉积物微生物群落和Fe/Mn矿物对As转化的巨大贡献。As分馏和竞争吸附的变化增加了0-10mm表面沉积物中溶解的As浓度。非特异性和特异性吸附的As是沉积物中溶解的As的主要来源。具体来说,As[V]的微生物还原和Fe氧化物的溶解增加了SWI（20至-20mm）处溶解的As浓度。当前研究的结果强调了水产养殖对沉积物中As释放的积极增强作用。
