氧化铜纳米颗粒(CuO NPs)对土壤环境因子与砷生物有效性的影响

氧化铜纳米颗粒（CuO NPs）可以通过农药和肥料施用、意外泄露或污水灌溉进入As污染农田土壤,从而对土壤环境因子和As生物有效性产生影响.本试验选取两种不同类型土壤（安徽宿松黄棕壤和黑龙江海伦黑土）进行人工As污染,添加不同浓度的CuO NPs,探究90 d淹水-落干过程中CuO NPs对As污染农田环境因子和As生物有效态的影响.结果表明,CuO NPs进入土壤后12 h内快速溶解产生Cu²⁺,且在黄棕壤中的溶解速度较黑土迅速.CuO NPs可在短时间内降低土壤pH,提高土壤氧化还原电位（E_h）,降低土壤电导率（EC）,但随着培养时间增加土壤EC逐渐提高.一定时间内CuO NPs在两种类型土壤中可降低51.0%~82.5%土壤浸出液中的As和15.7%~66.5%的As生物有效性,减少淹水时Fe （II）的含量.但在土壤落干时期产生一定的“纳米效应”从而促进了Fe （II）的产生.研究表明,CuO NPs进入As污染农田改变了土壤环境因子,一定时间内降低了土壤As生物有效性.

Effects of copper oxide nanoparticles (CuO NPs) on soil environmental factors and the bioavailability of arsenic

Copper oxide nanoparticles (CuO NPs) are exposed to arsenic (As) contaminated soil by pesticide, fertilizer application and accidental leakage, and have impact on the soil environmental factors and the bioavailability of As. In this experiment, 3 levels of CuO NPs were added in two different types of soil (Susong yellow brown and Hailun black soil) with artificial As contamination, to explore the effect of CuO NPs on As contaminated soil environmental factors and the bioavailability of As during a 90 days of submergence and re-drying process. The results showed that CuO NPs dissolved rapidly within 12 h after entering the soil and released Cu²⁺, and the dissolution rate in yellow brown soil was higher than that in black soil. CuO NPs reduced soil pH, increased soil E_h, and decreased soil EC within 10 days, but CuO NPs increased EC with the flooding time prolonged further. CuO NPs reduced dissolved As and bioavailability of As concentrations by 51.0%~82.5% and 15.7%~66.5%, respectively, in two types of soil. CuO NPs reduced Fe(II) content on flooding condition, but "nano-effect" of CuO NPs was occurred on re-drying process and increased Fe(II) content. Our study showed that the entry of CuO NPs into As contaminated soil changed soil environmental factors and reduced As bioavailability for a certain period of time.