The clayey aquitard has the potential to release geogenic poisonous chemicals such as arsenic (As) to the adjacent aquifer owing to complex hydrologic or biogeochemical processes. However, it remains unclear whether the aquitard has effect on As enrichment in the underlying aquifer in regions without extensive groundwater pumping, and the related processes have been poorly known. Based on piezometer water chemistry, stable water isotopes, sediment chemistry and reactive-transport model, this study aims to reveal the impact process of the aquitard to As accumulation of underlying aquifer from central Yangtze River Basin, a As-affected area without extensive groundwater pumping. On the whole, As migrated from top to bottom of the aquitard (especially the depth over 10 m) and significantly influenced the As accumulation in the underlying aquifer. Nonetheless, the results of three topical boreholes showed two different hydrogeological conditions affected As release in the aquitard and enrichment in the underlying aquifer. Different hydrogeological conditions could result in the input of different species organic carbon and then impact As concentrations in the aquifer. When the aquitard was near surface water bodies, the reductive dissolution of iron oxides was the main driver for As release and the aquitard had a significant influence on the enrichment of arsenic in the aquifer. At areas without surface water bodies nearby, the desorption of As(V) from minerals was the main source of As and the concentrations of As in pore water were quite low; this pattern had little effect on the enrichment of arsenic in the aquifer.

由于复杂的水文或生物地球化学过程，黏土型水母具有潜在的向邻近的含水层中释放诸如砷（As）等地源性有毒化学物质的潜力。但是，尚不清楚在没有大量抽水的地区，该水母是否对下层含水层中的砷富集有影响，而且相关过程还鲜为人知。本研究基于压力计水化学，稳定的水同位素，沉积物化学和反应输运模型，旨在揭示长江中下游水淹对底层蓄水层中砷的积累过程的影响过程。 。总体而言，砷从quit水的顶部到底部迁移（特别是深度超过10 m），并且显着影响了下层含水层中的As积累。尽管如此，三个局部钻孔的结果表明，两种不同的水文地质条件影响了水体中砷的释放和下层含水层的富集。不同的水文地质条件可能会导致输入不同种类的有机碳，进而影响含水层中的As浓度。当海葵在地表水体附近时，氧化铁的还原溶解是As释放的主要驱动力，而海葵对含水层中砷的富集有显着影响。在附近没有地表水体的地区，矿物质中As（V）的解吸是As的主要来源，孔隙水中As的浓度很低。这种模式对含水层中砷的富集几乎没有影响。三个局部钻孔的结果表明，两种不同的水文地质条件影响了阿奎德中砷的释放和下伏含水层的富集。不同的水文地质条件可能会导致输入不同种类的有机碳，进而影响含水层中的As浓度。当海葵在地表水体附近时，氧化铁的还原溶解是As释放的主要驱动力，而海葵对含水层中砷的富集有显着影响。在附近没有地表水体的地区，矿物质中As（V）的解吸是As的主要来源，孔隙水中As的浓度很低。这种模式对含水层中砷的富集几乎没有影响。三个局部钻孔的结果表明，两种不同的水文地质条件影响了阿奎德中As的释放和下层含水层的富集。不同的水文地质条件可能会导致输入不同种类的有机碳，进而影响含水层中的As浓度。当海葵在地表水体附近时，氧化铁的还原溶解是As释放的主要驱动力，而海葵对含水层中砷的富集有显着影响。在附近没有地表水体的地区，矿物质中As（V）的解吸是As的主要来源，孔隙水中As的浓度很低。这种模式对含水层中砷的富集几乎没有影响。