| The Lanmuchang mercury thallium mine in Xingren City,Guizhou Province is a typical Hg-Tl mineralization associated with As and Sb metals in China.The mining area of thallium and mercury mines has a history of more than 300 years.a large number of wastes such as waste slag,tailings,waste rock(hereinafter collectively referred to as mercury-thallium ore waste)produced in the process are stored in the environment for a long time.After strong weathering and rainwater leaching,Hg,Tl,As,a large number of highly toxic pollutants such as Sb continue to enter the surrounding and downstream soil and water environments,causing potential hazards to the health of the surrounding population and the environment.,which will cause potential harm to the health of the surrounding population and the environment and ecology.Therefore,effectively preventing the release and migration of highly toxic pollutants in the large amount of mercury thallium ore wastes stored in the open air in this area is increasingly important to protect the ecological environment of the surrounding and downstream areas.Pollution control and ecological restoration of mining and metallurgical waste dumps are of great significance to reduce the environmental impact of mines and improve the environmental ecology of mines.Compared with traditional physical treatment,vegetation restoration has the advantages of lower secondary pollution risk,high cost-effectiveness and environmental friendliness,etc.It is widely used in the restoration of the ecological environment of mine tailings,and the poor vegetation environment of waste storage yards often becomes the main restriction on vegetation restoration.Therefore,for the wastes from the mercury-thallium mines piled in the open-pit of Lanmuchang Mercury-thallium mine,this article uses on-site surveys and sampling studies to grasp the characteristics of waste pollution release,and the joint regulation of plant improvement-pioneer plants on the waste The research on the effect of pollutant release in-situ control is expected to provide a theoretical basis for the in-situ control of pollutant release and environmental ecological restoration in polymetallic mine mining and metallurgical waste dumps.The main research results obtained are as follows:(1)The six kinds of mining and metallurgical wastes from the Lanmuchang Mercury-thallium mining area are all acidic and have high salinity,and the acid neutralization ability is all less than 0.the total sulfur content,net acid production,and its leaching solution in W2 waste have the highest inhibition rate on bacterial luminescence intensity,indicating that it is the most toxic.Correlation analysis shows that both the sulfate content and total sulfur content in the waste are negatively correlated with the acid-soluble heavy metal content,but the negative correlation coefficients of total sulfur and acid-soluble heavy metal content are higher than sulfate,therefore,reduce and delay The oxidation of sulfur in the waste has positive significance for the control of the acid-soluble metals with high bioavailability in the waste.In addition,morphological analysis showed that the typical highly toxic pollutants in different types of wastes and surrounding farmland soils are mainly in residue form,but the content of Tl,Hg,As and Sb of unstable components in farmland soil are 18.9? 66.1 mg/kg,8?22.2 mg/kg,23.1?57.1 mg/kg and 0.59?3.2mg/kg,there are still great environmental and ecological risks.(2)The plant improvement-pioneer plant joint regulation study showed that the average Hg and Tl contents in the leached liquid obtained from the control group's waste leaching three times were 14.8 ?g/L and 170.6 ?g/L,and the average As and Sb were 22.1 ?g/L and 4.9 ?g/L,there is a risk of continuous release into the environment under rainwater leaching;the combined regulation effect reduces the leaching volume of the leaching test by 27.4%?29.4%,and significantly reduces the redox potential and biological toxicity of the leaching liquid.In addition,joint regulation can have a significant inhibitory effect on the release of Tl and Hg in the waste.The Tl content of the leaching liquid is reduced to 12.2%-54.1% of the control,and the Tl content of the leaching liquid of the mixed group with a 10% carbonate gradient is 19.6 ?g/L,the effect is the best;the Hg content in the leached liquid of the5% and 10% carbonate gradient trilobe group and mixed group is significantly lower than the control level(p<0.05),and it is 34.5%?47.9 lower than the control.%;while the joint regulation results in the release of As and Sb in the waste.Correlation analysis shows that the increase in the content of soluble organic matter in the waste matrix caused by the addition of plant amendments and the dissolution of free iron oxide induced by plants may lead to As and Sb.The key factor of release.(3)Plant improvement-joint regulation of pioneer plants can significantly improve the habitat of waste substrates,promote the development of waste substrates in a benign direction,and jointly regulate the content and substrates of plant nutrients(AN,TN,AP,TP,OM)in the wastes.The activity of enzymes(sucrose,catalase,urease,phosphatase)was significantly increased,and the sulfate content and net acid production in the waste were significantly reduced.In addition,morphological analysis shows Plant improvement-pioneer plant joint regulation has significantly increased the content of plant nutrients(AN,TN,AP,TP,AK,OM)and matrix enzyme activities(invertase,catalase)in mercury-thallium mine wastes(p<0.05)to make the waste develop in a benign direction.The morphological analysis results show that the combined regulation promotes the residual Hg and Tl content in the mercury thallium ore waste to rise from 15 mg/kg,184.6 mg/kg to 15.4?19.1 mg/kg and 184.9?191.1 mg/kg,respectively,and make it.Stable residue state transformation;for Tl with the highest content in waste,analysis from the perspectives of controlling its release,planting above-ground accumulation risks and improving the ecological landscape of the storage yard,5% carbonate rock and cow dung are coordinated to improve and plant clover The(S5)treatment constitutes the greatest benefit.In summary,the joint regulation of plant improvement-pioneer plants can significantly inhibit the release of some highly toxic pollutants,reduce the biological toxicity of the leachate,and improve the harsh plant environment of the waste,but all needs to be considered.Will adding plant bio-modifiers cause environmental risks caused by the activation and release of As and Sb.Therefore,the joint regulation has a good effect on the in-situ control of Tl and Hg release in the waste. |
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