School of Science, Engineering and Environment, University of Salford, Manchester, M5 4WT, United Kingdom.
School of Science, Engineering and Environment, University of Salford, Manchester, M5 4WT, United Kingdom.
Sci Total Environ. 2020 Jul 1;724:138223. doi: 10.1016/j.scitotenv.2020.138223. Epub 2020 Mar 25.
Microcosm and field investigation were conducted to examine the effects of heavy metals on the decomposition and accumulation of organic carbon in contaminated Mersey estuarine floodplain, northwest England. The results show that inhibition of microbially mediated decomposition of organic matter occurred in the water-inundated soils. However, individual heavy metals had differential effects on the inhibition of soil organic matter decomposition with arsenic and copper being much stronger, as compared to other investigated heavy metals. The weak inhibitory effects of chromium on organic matter decomposition was due to the conversion of highly toxic Cr(VI) to less toxic Cr(III) under reducing conditions. Lead also had a weaker capacity to inhibit organic matter decomposition due to its low solubility. It was surprising that the same phenomenon was not clearly observed during the field examination. The inhibitory effects of heavy metals on soil organic matter decomposition could be curtained under field conditions. pH, Eh and EC played more important roles, as compared to soil-borne heavy metals, in affecting the soil carbon dynamics in the contaminated Mersey estuarine floodplain.
采用微宇宙和野外调查方法，研究了重金属对英格兰西北部默西河口洪泛区污染土壤中有机碳分解和积累的影响。结果表明，水淹土壤中微生物介导的有机物分解受到抑制。然而，个别重金属对土壤有机质分解的抑制作用存在差异，砷和铜的抑制作用比其他研究的重金属更强。铬对有机物分解的弱抑制作用是由于在还原条件下，高毒性的 Cr(VI)转化为低毒性的 Cr(III)。由于铅的溶解度低，其抑制有机物分解的能力也较弱。令人惊讶的是，这一现象在野外调查中并没有明显观察到。在野外条件下，重金属对土壤有机质分解的抑制作用可能会受到抑制。在受污染的默西河河口洪泛区，pH、Eh 和 EC 对土壤碳动态的影响比土壤传播的重金属更为重要。
