Environment Chemical Behavior Of The Familiar Heavy Metals In Rhizosphere Sediment Scirpus Mariqueter

This study reviewed the definition, types, mechanisms, applications, affecting factors, such as basic theory of phytoremediation technology, analyzed research progress during the degradation of pollutants in the coastal wetlands. In view of the key technical problems in governance beach pollution, how the plant roots affected directly the total amount and the chemical form of pollutants in rhizosphere sediments and further affected indirectly the mechanism of biological contaminants. This research set the environment chemical behavior of the familiar heavy metals in rhizosphere sediment Scirpus mariqueter as research objectives, and discussed the technical feasibility of phytoremediation of the beach pollutants.On the basis of the investigation of familiar heavy metals spatial and temporal background distribution in the south bank of Hangzhou Bay, the beach polluted more seriously by heavy metal near the town of Chongshou in Ningbo Cixi was studied as the sample region. A three-year successive field investigation and laboratory analysis were conducted for research on the content of heavy metal (Cu, Zn, Pb and Cd), of different chemical forms under seasonal changes and main factors of bioavailability during physiological period in(spring, summer, autumn and winter) in rhizosphere of Scirpus mariqueter. The factors include plant growth season, pH, phosphorus, Eh and dissolved oxygen.Results indicated that this plant had a repair effect on heavy metal pollution and season alternation affected the bioavailability. Specific conclusions are as follows: the exchangeable contents of Cu and Pb are higher in spring-summer with higher bioavailability accordingly, but lower in autumn and in winter with lower bioavailability. Particularly, the combination of carbonate and ferro-manganese oxides con-tents of Cu and Pb is also higher, indicative of potential bioavailability. However, the content of exchangeable Zn is low but the organic-bounded and residues account for its low bioavailability. For Cd, mostly it is in the residue of no bioavailability. In spring and in summer with the increase of pH, both the exchangeable and the ferro-manganese oxides in-creased, while the organic-bounded and the carbonate decreased, which improved their bioavailabilities. Furthermore, in autumn and in winter, the scenario is opposite to that of spring and summer. Inorganic phosphorus affects directivity the bioavailability in spring and summer, resulting in decrease of pH because of inorganic phosphorus decline. The bioavail-ability of heavy metal decreased with the increase in Eh and dissolved oxygen.