The effect study of vermicompost and sepiolite on copper and arsenic stabilization on the contaminated soils Neda Khodadadi Lory n.khodadadi@cv.ac.ir Sep 20 2020 Department of Civil Isfahan University of Technology, Isfahan 84156-83111, Iran Degree:M.Sc language: farsi Hasti Hasheminejad , hhasheminejad@cc.iut.ac.ir The toxicity of heavy metals and the risk of their bioaccumulation in the human and animal food chain is one of the major environmental and health problems in modern societies. Primary sources of soil contamination are heavy metals from fossil fuel combustion, mining, metal smelting, municipal waste, fertilizers and insecticides, and sewage sludge. Stabilization of contaminated soils is one of the cost-effective and easy methods to reduce the spread of contaminants in the soil and prevent their transfer to the plant. Due to the high contamination of copper and arsenic elements in the soil around Khatunabad copper smelter, a research was carried out with the aim of stabilizing copper and arsenic in this contaminated soil by the mineral sepiolite and vermicompost. The soil required for this study was collected from Khatunabad copper smelter with a total concentration of copper and arsenic of 1492 and 74.2 mg/kg, respectively. For this purpose, sepiolite mineral in three levels of 0, 2 and 5% by weight and vermicompost fertilizer in three levels of 0, 1 and 2% by weight were mixed with soil by a factorial design the resulting mixture was transferred into pots of one Kg to sow corn seeds. The plants were harvested 20 days after planting. Then they sent to the laboratory along with potting soil to determine pH, EC, plant growth parameters such as aerial and root dry weight, determine the concentration of copper and arsenic elements in the plant and determine the amountbioavailability of DTPA-extracted copper and arsenic metals. The results showed that sepiolite increased soil pH and decreased soil Ec. Sepiolite showed a high ability to stabilize copper and prevent its transfer to the plant, so that the addition of sepiolite at levels 2 and 5% reduced the concentration of copper in the roots of the plant to 46 and 52% compared to its zero level. Addition of sepiolite at 5% level also reduced the available copper concentration of DTPA extract by 50% compared to the blank sample. The concentration of copper in the aerial parts of the plant decreased by 73 and 92% compared to the zero level by applying 1 and 2% by weight of vermicompost, respectively. Due to the interaction effects of stabilizers on the concentration of copper in the aerial parts of the plant at the level of 2 and 5% by weight of sepiolite, the addition of vermicompost at the level of 2% increased the concentration of copper in the aerial parts compared to zero, but not much. There was no witness. Among the compounds used, sepiolite at 5% level and vermicompost at 1% level had better performance for copper stabilization considering the growth parameters. However, in the present study, there was no evidence of the effect of sepiolite and vermicompost on the stabilization and mobility of arsenic. The use of sepiolite and vermicompost caused the absorption of copper and reduced its transfer to the plant. Keywords : Stabilization, Sepiolite mineralization, Vermicompost, DTPA, Copper, Arsenic.