大豆秸秆生物炭对铅锌尾矿污染土壤的修复作用

采用盆栽空心菜的方法,研究了大豆桔杆生物炭对铅锌尾矿污染土壤的修复作用。污染土壤中Cu、Zn、Pb和Cd含量分别为50,400,1 119,3.4mg/kg。结果表明:土壤无论是否受到铅锌尾矿污染,添加3%生物炭(w/w)均能显著提高土壤pH;3%生物炭能够抑制铅锌尾矿污染导致的土壤pH降低。大豆桔杆生物炭对尾矿污染土壤和未污染土壤中重金属有效态的影响不同,与未污染土壤相比,3%生物炭的钝化作用不能抵消铅锌尾矿污染导致的重金属有效态含量的增加。铅锌尾矿污染抑制空心菜生长;施加3%生物炭可以消除铅锌尾矿污染对空心菜生长的抑制作用。生物炭显著降低污染土壤空心菜根部重金属含量,而对地上部分的影响,不同元素表现出不同的特点;3%生物炭能够阻控铅锌尾矿污染土壤中Cu、Zn、Pb和Cd向空心菜地上部迁移富集。大豆桔杆生物炭对空心菜吸收重金属的影响,在铅锌尾矿污染土壤和未污染土壤上表现不同,存在元素之间的拮抗作用以及由于生物炭提高空心菜生物量所产生的稀释作用。在研究设置条件下,与未污染土壤相比,从空心菜生物量和可食部分吸收重金属含量来评价,施加3%大豆桔杆生物炭可以修复铅锌尾矿导致的土壤污染。

Remediation of Soil Polluted by Lead-Zinc Tailings Using Soybean Straw Biochar

The method of potted swamp cabbage was adopted to research the remediation effects of soybean straw biochar on soil contaminated by lead-zinc tailings. In the contaminated soil, the concentration of Cu, Zn, Pb and Cd was 50, 400, 1 119 and 3.4 mg/kg, respectively. The results showed that whether the soil contaminated by lead-zinc tailings or not, adding 3% biochar could significantly improve soil pH and inhibit the soil pH value reduction leaded by lead-zinc tailings pollution. Soybean straw biochar had different effects on effective state of heavy metals in soil contaminated by tailings and uncontaminated soil; compared with the uncontaminated soil, the passivation of 3% biochar could not offset the increase of bioavailability of heavy metal caused by lead-zinc tailings pollution. The pollution of lead-zinc tailings inhibited the growth of water spinach, and the application of 3% biochar could eliminate the inhibitory effect. Biochar significantly reduced heavy metal content of swamp cabbage roots in pollution soil, but in the aboveground part of swamp cabbage, biochar had different effects on different heavy metals; adding 3% biochar could prevent the migration of Cu, Zn, Pb and Cd from lead-zinc tailings contaminated soil to shoot of swamp cabbage. The effect of soybean straw biochar on the absorption of heavy metals in swamp cabbage was different in lead-zinc tailings contaminated soil and uncontaminated soil, there were interaction between elements, and dilution effect caused by biomass increase of swamp cabbage after adding biochar. Under the experimental conditions, evaluating from the biomass and heavy metal content in the edible parts of swamp cabbage, applying 3% soybean straw biochar could remedy pollution soil leaded by lead-zinc tailings.