Salt-soil Agricultural Center, Key Laboratory of Agricultural Environment in the Lower Reaches of Yangtze River Plain, Institute of Agricultural Resource and Environment, Jiangsu Academy of Agriculture Sciences, 50 Zhongling Rd, Nanjing, 210014, PR China.
College of Environmental Science and Engineering, Yangzhou University, Yangzhou, PR China.
Environ Pollut. 2020 Jun;261:114103. doi: 10.1016/j.envpol.2020.114103. Epub 2020 Jan 29.
Periphyton plays a significant role in heavy metal transfer in wetlands, but its contribution to cadmium (Cd) bioavailability in paddy fields remains largely unexplored. The main aim of this study was to investigate the effect of periphyton on Cd behavior in paddy fields. Periphyton significantly decreased Cd concentrations in paddy waters. Non-invasive micro-test technology analyses indicated that periphyton can absorb Cd from water with a maximum Cd influx rate of 394 pmol cm s and periphyton intrusion significantly increased soil Cd concentrations. However, soil Cd bioavailability declined significantly due to soil pH increase and soil redox potential (Eh) decrease induced by periphyton. With periphyton, more Cd was adsorbed and immobilized on organic matter, carbonates, and iron and manganese oxides in soil. Consequently, Cd content in rice decreased significantly. These findings give insights into Cd biogeochemistry in paddy fields with periphyton, and may provide a novel strategy for reducing Cd accumulation in rice.
底栖藻类在湿地重金属迁移中起着重要作用，但它对稻田中镉（Cd）生物可利用性的贡献在很大程度上仍未得到探索。本研究的主要目的是研究底栖藻类对稻田中 Cd 行为的影响。底栖藻类显著降低了稻田水中的 Cd 浓度。非侵入性微测试技术分析表明，底栖藻类可以从水中吸收 Cd，最大 Cd 流入率为 394 pmol cm s，并且底栖藻类的侵入显著增加了土壤中的 Cd 浓度。然而，由于底栖藻类引起的土壤 pH 值升高和土壤氧化还原电位（Eh）降低，土壤中 Cd 的生物有效性显著下降。在底栖藻类的作用下，更多的 Cd 被吸附和固定在土壤中的有机物、碳酸盐和铁锰氧化物上。因此，水稻中的 Cd 含量显著降低。这些发现深入了解了有底栖藻类的稻田中 Cd 的生物地球化学特性，并可能为减少水稻中 Cd 积累提供一种新策略。
