Accumulation and distribution of cadmium at organic-mineral micro-interfaces across soil aggregates

作者：Qi Li, Linfeng Li, Bohao Yin, Xiaoyang Lin, Anwen Xiao, Weijie Xue, Hengjie Liu, Yichun Li · 发表于：Ecotoxicology and Environmental Safety · 年份：2024 · DOI：10.1016/j.ecoenv.2024.117457 · 被引用次数：10 · 研究领域：Heavy metals in environment、Geochemistry and Geologic Mapping

Soil amendments are crucial in regulating cadmium (Cd) distribution as aggregates of varying sizes have different capacities to retain soil Cd. Directly observing the Cd distribution within aggregates and understanding their interactions with minerals and carbon at the submicron scale remain significant challenges. Pot experiments were conducted to assess the impacts of mineral, organic, and microbial amendments on the Cd distribution in soil aggregates using synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectroscopy and nano-scale secondary ion mass spectrometry (NanoSIMS). Our results revealed that different soil amendments exerted varying effects on Cd accumulation in soil aggregates. The mineral and microbial amendments facilitated the Cd transfer from the macroaggregates to the silt+clay fraction, while the organic amendment increased the Cd loading in the macroaggregates. Additionally, the mineral and microbial amendments reduced the binding of Fe oxides with microbial-derived peptides in the macroaggregates and enhanced the interaction of Fe oxides with plant-derived lignin in the silt+clay fractions. Furthermore, NanoSIMS analysis provided direct evidence that the mineral and microbial amendments decreased the association between Cd with carbon and minerals in the macroaggregates, while they enhanced the binding of Cd and Fe oxides in the silt+clay fractions. Collectively, our findings revealed that the mineral and microbial amendments promoted Cd t...