| 其他摘要 | mercury is toxic heavy metal which is not necessary for human being. As the development of the industry and taping of the mercury mines, mercury pollution has become an important environmental issue. According to the report, every year about 1.9×105ton mercury is dumped to the environment and pollute mass of soil threating people’s health. Stabilization/solidification, chemical immobilization, thermal desorption, electro-remediation, soil washing, phytostablization, phytoexaction and phytovalization techniques have been adopted to remedy the heavy-metal contaminated soil. In situ chemical immobilization aims to decrease the percentage of bioavailability and the accumulation of heavy-metal in plants by adding innocuous materials to facilitate series of chemical reactions including precipitation, adsorption, ion exchange and redox. Because of simplicity and efficiency, in situ chemical immobilization is a promising technique for the remediation of heavy-metal contaminated soil. The purpose of this paper was to investigate the potential of in situ chemical immobilization to remediate mercury contaminated soil at Wanshan. This was achieved through: The select of material to stabilization mercury by laboratory test; The effect of bentonite and diammonium phosphate on the removing of mercury in water; The field study of bentonite and diammonium phosphate in remedying mercury contamination site in Wanshan. The major results including: 1. Diatomaceous earth, humic acid, zeolite, bentonit, lime, combined zeolite and humic acid, combined bentonit and diammonium phosphate, combined zeolite and diammonium phosphate and combined zeolite and humic acid are used as amends, only the amend of combined bentonit and diammonium phosphate can cause the effectively decrease of bioavailable and Fe/Mn-oxide bound Hg content by comparing with the control. 2. By the adsorbing test, bentonit and diammonium phosphate together can have an effect on the remove of mercury in water under the pH 3 to pH 10. About 98% mercury can be removed at the pH 5. 3. In the field study，The results showed that the application of bentonite, diammonium phosphate, as well as a mixture of the compounds can increase the dry biomass of plants compared with the control. Specifically, the combined treatment resulted in a significant boost of dry biomass. In this combined treatment case, the biomass Hg content was also significantly lower than controls, while this effect was insignificant in single compound treatments. The plants received the treatment of 3% bentonite and 0.5% diammonium phosphate revealed the lowest Hg content in various plant tissue.Concerning the combined treatments, chemical analysis of Hg fractions present in plant soil before and after the remediation period indicated a significant drop-off in bioavailable Hg (soluble and exchangeable, specifically sorbed fractions) and Fe/Mn-oxide bound Hg content, while the content of Hg associated with organic bound and residual fractions were relatively stable. |
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