老化对干湿和冻融循环模拟的历史污染碱性农田中生物炭对 Cd 和 Ni 的稳定化及酶活性的影响。
Effect of aging on stabilization of Cd and Ni by biochars and enzyme activities in a historically contaminated alkaline agricultural soil simulated with wet-dry and freeze-thaw cycling.
机构信息
MOE Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
MOE Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
出版信息
Environ Pollut. 2021 Jan 1;268(Pt A):115846. doi: 10.1016/j.envpol.2020.115846. Epub 2020 Oct 27.
Natural aging alters the surface physicochemical properties of biochars, which can affect the retention of heavy metals. This work investigated the effect of biochar aging on stabilization of heavy metals (Cd and Ni) and soil enzyme activities simulated with laboratory wet-dry (WD) and freeze-thaw (FT) cycling. A wheat straw (WS) biochar and a corn straw (CS) biochar were subjected to 30 WD or FT cycles, and Cd- and Ni-contaminated alkaline soils amended with the two fresh biochars (at 5% w/w) were subjected to 30-day constant moisture incubation and 30 WD or FT cycles. WD and FT aging caused slight reduction in the pH of the biochars, significant increases in their O contents and surface areas, and formation of new carbonate minerals. WS biochar was more effective than CS biochar at reducing the phytoavailable Cd in the soil, with reduction of 12.1%, 14.6%, and 12.9% under constant moisture incubation, WD aging, and FT aging, respectively. Reduction in phytoavailability of Ni by the addition of biochars was observed only under WD aging, by 17.0% and 18.5% in the presence of WS and CS biochars, respectively. Biochar amendment also reduced the distribution of Cd in the acid soluble and reducible fractions in all aging regimes. The addition of biochars decreased catalase activity in almost all aging regimes and invertase activity under FT aging, but increased urease activity under FT aging. Comparison of the enzyme activities in the soils amended with biochars under constant moisture and accelerated aging conditions indicates WD aging significantly decreased the activities of catalase, invertase, and urease in all treatments, while FT aging significantly increased urease activity in all treatments. These findings suggest that biochars can stabilize Cd in alkaline soils under changing environmental conditions, although the activities of some soil enzymes could be negatively impacted.
自然老化会改变生物炭的表面物理化学性质，从而影响重金属的保留。本研究探讨了生物炭老化对重金属（Cd 和 Ni）稳定化和实验室干湿（WD）和冻融（FT）循环模拟的土壤酶活性的影响。采用小麦秸秆（WS）生物炭和玉米秸秆（CS）生物炭进行 30 次 WD 或 FT 循环，然后将两种新鲜生物炭（按 5%w/w）添加到 Cd 和 Ni 污染的碱性土壤中，进行 30 天恒湿培养和 30 次 WD 或 FT 循环。WD 和 FT 老化导致生物炭的 pH 值略有降低，O 含量和表面积显著增加，形成了新的碳酸盐矿物。在恒湿培养、WD 老化和 FT 老化条件下，WS 生物炭比 CS 生物炭更有效地降低土壤中可植物利用的 Cd，分别降低了 12.1%、14.6%和 12.9%。只有在 WD 老化条件下，添加生物炭才会降低 Ni 的可植物利用性，WS 和 CS 生物炭的降低率分别为 17.0%和 18.5%。生物炭添加还降低了所有老化条件下 Cd 在酸可溶和可还原部分的分布。在几乎所有的老化条件下，添加生物炭都会降低过氧化氢酶的活性，在 FT 老化条件下会降低转化酶的活性，但会增加 FT 老化条件下的脲酶活性。比较在恒湿和加速老化条件下添加生物炭的土壤中的酶活性表明，WD 老化显著降低了所有处理中过氧化氢酶、转化酶和脲酶的活性，而 FT 老化显著增加了所有处理中脲酶的活性。这些发现表明，生物炭可以在不断变化的环境条件下稳定碱性土壤中的 Cd，尽管一些土壤酶的活性可能会受到负面影响。
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