College of Ecology & Environment, Hainan University, Haikou, Hainan, 570228, PR China; State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, 570228, PR China; Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou, Hainan, 570228, PR China; Center for Eco-Environmental Restoration Engineering of Hainan Province, Hainan University, Haikou, Hainan, 570228, PR China; Key Laboratory for Environmental Toxicology of Haikou, Hainan University, Haikou, Hainan, 570228, PR China.
College of Ecology & Environment, Hainan University, Haikou, Hainan, 570228, PR China; State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, 570228, PR China; Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou, Hainan, 570228, PR China; Center for Eco-Environmental Restoration Engineering of Hainan Province, Hainan University, Haikou, Hainan, 570228, PR China; Key Laboratory for Environmental Toxicology of Haikou, Hainan University, Haikou, Hainan, 570228, PR China.
Chemosphere. 2020 Dec;261:128122. doi: 10.1016/j.chemosphere.2020.128122. Epub 2020 Aug 28.
Heavy metals in soil are harmful to human health via the food chain, but little is known about the mechanism of reducing bioavailability of Cd or Pb to maize (Zea mays L.) by applying complex amendments to soil. A field experiment was conducted at a tropical site in Hainan Province, China, that had been subjected to soil pollution by Cd and Pb from past mining activities. There were ten treatment groups comprising a mixture of biochar, hydroxyapatite (HAP), manure, and plant ash in varying proportions and at three different rates. Compared with untreated soil, all treatments increased pH by 2-3 units in bulk soil or 1-2 units in rhizosphere soil. For all amendments, the concentration of Cd in all parts of maize plants was decreased compared with unamended soil, but this effect was much smaller for Pb. The greatest effect was found with a mixture containing the ratio of HAP:manure:biochar:plant ash as 6:4:2:1 when applied at 20.1 t ha. The dominant microbial group in contaminated soil was Proteobacteria. There is evidence that this group can immobilize Cd by mechanisms that include biosorption and bioprecipitation. It was concluded that the mixed amendments containing biochar, HAP, manure, and plant ash can be useful in decreasing Cd uptake by maize. The amendment in this study likely operates through a combination of soil chemical changes and by influencing the soil-microbe-plant interaction.
土壤中的重金属通过食物链对人类健康有害，但对于通过向土壤中施加复合改良剂来降低玉米（Zea mays L.）对镉或铅的生物利用度的机制知之甚少。在中国海南省的一个热带地区进行了一项田间试验，该地区曾受到过去采矿活动产生的镉和铅污染。有十个处理组，包括生物炭、羟基磷灰石（HAP）、粪肥和草木灰以不同比例和三种不同的速率混合。与未处理的土壤相比，所有处理均使原状土的 pH 值增加了 2-3 个单位，根际土的 pH 值增加了 1-2 个单位。对于所有的改良剂，与未施肥的土壤相比，所有玉米植株各部位的镉浓度均降低，但对于铅的影响要小得多。当以 20.1 t ha 的比例施加 HAP:粪肥:生物炭:草木灰比为 6:4:2:1 的混合物时，效果最大。受污染土壤中的主要微生物群是变形菌门。有证据表明，该菌群可以通过生物吸附和生物沉淀等机制固定镉。研究结果表明，含有生物炭、HAP、粪肥和草木灰的混合改良剂可有效降低玉米对镉的吸收。本研究中的改良剂可能通过土壤化学变化和影响土壤-微生物-植物相互作用来发挥作用。
