LI Xinlong1, WU Yonggui1,2,3, WEN Jichang1, ZHU Xinwei1
(1. College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025;
2. Institute of Applied Ecology, Guizhou University,Guiyang 550025;
3. Guizhou Karst Environmental Ecosystem Observation and Research Station, Ministry of Education, Guizhou University, Guiyang 550025; )
Abstract:In order to evaluate the effect of plant growth condition modifier and pioneer plants on the control of pollutants migration in the waste of mining, mercury-thallium wastes, including the mining and metallurgical waste residues, tailings and waste rock in Lanmuchang, Xingren city of Southwest Guizhou was studied by adding carbonate rock and decomposed cow manure as growth condition modifier, and by planting with Trifolium repens and Lolium perenne as pioneer plants for joint regulation, to evaluate the inhibition effect of these measures on the release of toxic pollutants Hg, Tl, As and Sb from waste by leaching experiments. The results showed that the average content of Hg and Tl in the leachate obtained from the control group was 14.8 μg/L and 170.6 μg/L, respectively, and the average content of As and Sb was 22.1 μg/L and 4.9 μg/L, respectively. There is a risk of continuous release of heavy metals into the environment; joint regulation has a significant inhibition effect on the release of Tl and Hg. The content of Tl in the leachate is reduced to 12.2%-54.1% of the control, with the T10 treatment has lowest Tl of 19.6 μg/L, which has the best inhibition effect; Hg content in the leachate of the S5,S10,T5 and T10 treatment was significantly lower than the control level (p<0.05), with a reduction of 34.5%-47.9%; while, the combined regulation resulted in the release of As and Sb in the waste. Correlation analysis indicated that the increase in the content of dissolved organic matter in the waste caused by the addition of plant growth condition modifier and the Fed induced by plants might be the key factor of the release of As and Sb. The chemical speciation analysis suggested that the joint regulation promotes the transformation of Hg and Tl in the waste to the residue state, and decrease of the proportion of the residue state of As and Sb. In summary, the use of plant growth condition modifier -Pioneer Plants joint regulation of mercury-thallium mine waste pollutants can significantly inhibit the release of Hg and Tl, but increase the release of As and Sb, which was induced by the increase of dissolved organic matter by adding plant growth condition modifier and this should be considered for this joint control.
Key word: Mercury-thallium mine waste slag; Carbonatite; Typical highly toxic pollutants; plant growth condition modifier; Transformation
EARTH AND ENVIRONMENT Vol.49, No.5, Tot No.343, 2021, Page 539-550
