Research Of Remediation Of BDE209-Cd Co-Contaminated Soil By Solanum Nigrum

Plant selection experiment was conducted to investigate the phytoremediation ofDecabromodiphenyl Ether （BDE-209） and Cadmium （Cd）, as the model pollutants of persistentorganic pollutants and heavy metal in soil and found Solanum nigrum could tolerate andremediate pollution.The study on the remediation in BDE-209, Cd single and combined pollutionsystems by Solanum nigrum was carried out which include the absorption of pollutant bySolanum nigrum, soil contaminant residues after repair, effect of remediation by Solanumnigrum adding surfactant and exogenous bacteria, morphology observation of Solanum nigrumin contamination system, soil microbial activity and community analysis. The research aimed toprovide values on phytoremediation of Polybrominated diphenyl ethers-heavy metals combinedpollution in soil.The tested plants have a certain ability to uptake and accumulate pollutants. The BDE-209contents in the plant could be up to18.01mg·Kg^-1, the Cd content could be up to422.11mg·Kg^-1.After60days remediation, a sequence of the plants remediation effect from high to low wasPennisetum alopecuroides, Solanum nigrum in single BDE-209contaminated system; Andanother sequence was Ipomoea aquatica Forsk, Houttuynia cordata Thunb, Brassica juncea,Sonchus brachyotus D C. While in combined pollution system, plant remediation effect ofBDE-209and Cd from high to low in turn was Solanum nigrum, Pennisetum alopecuroides andIpomoea aquatica Forsk. As Solanum nigrum was the most ideal remediation plant throughexperiments of tolerance, absorption ability and the removal effect of pollutants in tested plants,a selection of Solanum nigrum as remediation plant for further experiments was defined.Surfactants and exogenous bacteria could strengthen the remediation of BDE-209、Cdcontaminated soil by Solanum nigrum. After60days remediation, The absorption andenrichment ability of BDE-209、Cd of Solanum nigrum are enhanced. The pollutants removaleffect was also increased, removal rate of BDE-209and Cd could be up to51.38%and9.08%.Morphological distribution characteristics of Cd in soil from high to low in turn was: residualform RES, exchangeable form EXC, carbonate bounded form CAB,Iron and manganese oxidecombination state Fe-Mn, organic combination state OM. Strengthening measures had a certainactivation on heavy metals in soil, encouraging residual form Cd to transform into bioavailableexchange state. Cd absorbed by plants above the ground are mainly difficult soluble heavy metal phosphates, pectinate and protein binding state. However, the presence of Cd in root was mainlycombined with protein and dissolved in water-soluble organic acids. The main forms of Cd inplants root were active state, contributing to transport and migrate; while in plant ground part, Cdwas mainly exists in a stable form, reducing its toxicity for long-term store. Simultaneouslyadding surfactant Tween80and exogenous white rot fungus, could reach the most obviousstrengthening remediation effect by Solanum nigrum.Combined remediation of Solanum nigrum-microbe played a significant role in promotingenzyme activity of dehydrogenase, polyphenol oxidase and urease in soil; the number of bacteria,fungi, actinomycetes in the soil increased significantly after remediation; The whole activity ofsoil microbial and the diversity of community structure function was significantly enhanced aswell. Results of principal component analysis showed that utilization of carbon sources of soilmicrobial were different, cluster analysis could classify different treatment according to therepair effect of pollutants in soil.