School of Environment and Tourism, West Anhui University, Lu'an, 237012, China.
School of Biology, Food and Environment, Hefei University, Hefei, 230601, China.
Environ Sci Pollut Res Int. 2020 Nov;27(32):40001-40008. doi: 10.1007/s11356-020-10028-3. Epub 2020 Jul 10.
Paddy soil contamination by cadmium (Cd) and arsenic (As) is a great concern. Field experiments were conducted to study the effects of steel slag (SS, 2.0 and 4.0 t ha) on the solubility of Cd and As in soil and their accumulation by rice plants grown in a historically co-contaminated paddy field with Cd and As. The results showed that SS amendment (4.0 t ha) significantly decreased soluble concentrations of Cd in pore-water but increased that of As, related to markedly elevated soil pH and soluble silicon, phosphorus of pore-water in rice rhizosphere at both heading and mature stages. The amendments also evidently decreased Cd but enhanced As in iron plaque on root surfaces, while the formation of iron plaque was not significantly increased. Further, SS amendment (4.0 t ha) markedly reduced Cd concentrations in rice tissues (roots, straw, and brown rice) by 48-78% at both stages, though increased As by 13-38%. Cadmium translocation from roots to aerial parts decreased significantly after the amendments, but not for As. Besides, SS application increased the biomass of roots, straw and grains, and root antioxidant enzyme activities. Collectively, steel slag decreased Cd accumulation in rice tissues and in iron plaque but increased those of As, likely due to steel slag decreasing soluble Cd and enhancing soluble As in pore-water, related to soil pH and soluble nutrients (Si, P), and restraining Cd translocation within rice. Our results indicate that steel slag represents a favorable potential for Cd-contaminated paddy soils, though it seems undesirable for Cd and As co-contamination.
农田土壤镉（Cd）和砷（As）污染是一个严峻的问题。本研究采用田间试验，研究了钢渣（SS，2.0 和 4.0 t·ha）对历史上同时受到 Cd 和 As 污染的稻田中土壤 Cd 和 As 溶解性及其在水稻植株中积累的影响。结果表明，SS （4.0 t·ha）添加显著降低了水稻根际土壤 Cd 在孔隙水中的可溶性浓度，但增加了 As 的可溶性浓度，这与水稻根际土壤 pH 和 Si、P 显著升高有关。SS 还明显降低了根表面铁膜中 Cd 的含量，但增加了 As 的含量，而铁膜的形成并未显著增加。此外，SS （4.0 t·ha）添加在两个生育期均显著降低了 Cd 在水稻各组织（根、茎和糙米）中的浓度，降幅为 48-78%，但增加了 As 的浓度，增幅为 13-38%。添加 SS 后，Cd 从根部向地上部的转运明显减少，但 As 没有减少。此外，SS 应用增加了根、茎和粒的生物量以及根的抗氧化酶活性。总的来说，钢渣通过降低土壤中 Cd 的溶解性并增加孔隙水中的 As 溶解性来降低水稻组织和铁膜中 Cd 的积累，但增加了 As 的积累，这可能是由于钢渣降低了土壤 pH 值和可溶性养分（Si、P），从而抑制了 Cd 在水稻体内的转运。研究结果表明，钢渣是一种有潜力的 Cd 污染稻田改良剂，但对 Cd 和 As 复合污染的稻田似乎并不理想。
