The Analyses Of Heavy-Metal Trace And Selection Of Heavy-Metal Accumulation Plants In Wetlands Of The Poyang Lake

To screen out a series of ideal native hyperaccumulators that can effectively remedy contaminated soils by heavy metals is the main groundwork of bioremediation engineering and the first step of its commercial application on a large scale, which is also front field of contaminated environment remediation. This study determined the evaluation of heavy metals pollution in Poyang Lake wetlands and the screening about native heavy metals hyperaccumulators as the major study contents. In this paper, Xiushui estuary, main branch estuary of Gan River , west branch estuary of Xing River, Le'an River estuary, Chang River estuary and Raohe estuary were investigated in November and December 2006. The content of Cu, Pb, Zn, Cd in samples and their speciation in soil samples were determined by Microwave Digestion and atomic absorption spectrophotometry (AAS), then datas were analyzed by Microsoft Office Excel and Statistical Package for the Social Sciences(SPSS). The results were as follows:1. Nemerow and potential ecological risk index indicated, Cu was the dominant factor of heavy metals pollution in the Poyang Lake wetlands, accompanied by Zn, Cd pollution, Pb pollution smallest. The heavy metals pollution degree was more in eastern of the Poyang Lake wetlands than in western. Cu, Pb, Zn were minor potential ecological hazards; Cd total was big and the potential ecological harm of Cd is strong, although most Cd can be transferred to the plants body, but would also like to pay special attention to the potential ecological harm.2. Cu was the secondary standard of environmental quality standard for soils at Le'an River estuary, west branch estuary of Xing River and Raohe estuary. Xiushui estuary and main branch estuary of Gan River were the first; Pb was the secondary of quality standards at all Sampling point; Zn was the third quality standards at Raohe estuary, secondary at west branch estuary of Xing River , Le'an River estuary, Xiushui estuary and main branch estuary of Gan River; Cd cause serious pollution, and more than the third soils quality standards, the degree of pollution followed: west branch estuary of Xing River > Le'an River estuary > Raohe estuary > Xiushui estuary > main branch estuary of Gan River.3. The organic matter-sulfide bound and residum speciation were the main content of Cu, Pb, Zn, Cd in wetland soils. The soluble and exchangeable speciation (bioavailable speciation) were less content of Cu, Zn, Cd and the bioavailable speciation was 1/3 of Pb total.4. The heavy metals in Plants was significantly related with their bioavailable speciation in root zone soils.5. Carex. was Pb native hyperaccumulators of Poyang Lake, and the concentration of Pb accumulated in frond was 65.73mg/kg, accmulation coefficient was 3.19, transport coefficient 17.15.Torilis japonica (Houtt.) DC. was Zn hyperaccumulators and Zn accumulated in leaves was 510.31 mg/kg, accmulation coefficient was 1.14, transport coefficient 1.6.Erigeron annuus (Linn.)Pers. was Zn, Cd native hyperaccumulators. Zn accumulated in frond was 256.75 mg/kg, accmulation coefficient was 1.2, transport coefficient 2.2. Cd accumulated in frond was 22.08 mg/kg, accmulation coefficient was 5.32, transport coefficient 23.42.CarduuscrispusL. was Zn, Cd hyperaccumulators. Zn accumulated in leaves was 599.52 mg/kg, accmulation coefficient was 1.86, transport coefficient 2.11. Cd accumulated in frond was 7.17 mg/kg, accmulation coefficient was 1.01, transport coefficient 3.25.Miscanthussacchariflorus and Herba GnapHaii Affinis were Cd native hyperaccumulators. The concentrations of Pb accumulated in frond were 3.66 mg/kg,5.54 mg/kg, accmulation coefficient 9.89 and 1.31, transport coefficient were 1.59 and 2.31.