Heavy Metal Accumulation Of Aquatic Plants In Sewage

Phytoremediation that is a new kind of ecological treatment has a good effect on the removel of heavy metals.The ecological sewage treatment plant was the research base in the test,and 6 kinds of aquatic plants which are Calamus,Canna,Thalia,Lythrum,Scirpus and Arundo donax were researched.The project aimed to analyzed the characteristics and regularity of heavy metals accumulation about aquatic plants,in order to provide referenced data for the ecological treatment of sewage and the phytoremediation of water bodies contaminated by heavy metals.The main conclusions are as follows:(1)Contacting time and the stage of plant growth were analyzed as two factors which influenced the accumulation of heavy metals in plants.The results showed that,heavy metals concentration in different plants all gone up steadily with time,but the accumulation in different plants are diverse.In general,the ability of enriching heavy metals in seedling growth period of plant performed poorly.Instead,there were more heavy metal bioaccumulation in the reproductive growth period of plants.(2)The distribution characteristics of heavy metals as well as the enrichment and transfer capacity of each organ of 6 kinds of plants were compared and analyzed.The results showed that,the enrichment of four kinds of heavy metals in different plants showed a significant difference.The accumulation in root is as 2-5 times as the above-ground organs of plants.Cd was the most easily enriched by plants.The competitive plants of Cu,Zn,Pb,Cd are as follows:Lythrum,Calamus,Calamus,Canna.Arundo donax,by contrast,performed poorly on enriching heavy metals.(3)Heavy metals accumulation and transfer characteristics of the competitive plants in two sewage treatment plants were discussed.The results showed that,the heavy metals accumulation of plants in two plants all showed an increasing trend with time.For the accumulation of heavy metals,there were differences on the same plant in different plant.The plants showed strong enrichment ability in the wastewater with high concentration of heavy metal,and they showed strong migration ability in the sewage environment with low concentration of heavy metal.Figure 39,Table 23,Reference 87.