Distribution And Ecological Risk Of Nutrients And Heavy Metals In Reclamation Project

Pudong airport reclamation project is located in the south branch of Yangtze estuary. It is the bigger reclamation project in rencent years,which causes great impact of the flat wetland landscape and ecosystem near this project. This dissertation took Pudong airport reclamation project as the research object and carried out research on ecologic nutrients of water, heavy metals in the whole process of reclamation in sediment and macrobenthos.The main investigations of this study were as follows: 1) monitoring nutrients(i.e., total nitrogen, total phosphorus,nitrate, nitrite, ammonium, phosphate, dissolved inorganic nitrogen) and environmental factors(i.e., dissolved oxygen, suspended, turbidity, water temperature, salinity, p H and chemical oxygen demand) to determine the seanonal distribution of nutrients and relationship between environmental factors and nutirents. The eutrophication of water bodies was also evaluated; 2) investigating heavy metals(i.e., Cu, Pb, Cd, Hg, As) in sediment and macrobenthos in the Pudong reclamation project area, and comparing to those in Jiuduansha Nature Preserve to assess the effect of reclamation project. Ecological risk of heavy metals in sediment and macrobenthos was analyzed. The major results of this dissertation were listed as follows:(1) Total nitrogen, total phosphorus, nitrate, nitrite,ammonium, phosphate, dissolved inorganic nitrogen were analyzed. The results showed that the main presence of dissolved inorganic nitrogen was nitrates, which accounted for from 84% to 97%, the highest level of nitrite and ammonium were present in spring, up to 0.639 mg/L and 0.098mg/L, the highest level of nitrate and total nitrogen were present in winter,up to 0.012 mg/L and 3.418 mg/L. The highest level of phosphate was present in autumn, up to 0.031 mg/L, the highest level of total phosphorus was present in summer, up to 0.322 mg/L. Seasonal variation of nutrients were different, this may be due to Yangtze River basin, agricultural irrigation, environmental factors and biological activity. Seasonal variation of the eutrophication index were 2.42 to 21.99, all greater than 1,which showed the water was over nutritious and limited by phosphate.The influence of Pudong airport reclamation project to nutrients is suspended.(2) The contents of heavy metals in sedimentduring the process of reclamation project were analyzed. The results showed that the concention of heavy metals was Cu>Pb>As>Cd>Hg. Except Cd greater than that in national soil standards level 2, other heavy metals were met national soil standards level 1. The contents of heavy metals in sediment of Pudong airport reclamation project were greater than those in Jiuduansha Nature Preserve. Cu and Pb had the same seasonal distribution, whereas other heavy metals were different. Potential ecology risk assessment illustrated that the pollution level and ecological risk of heavy metals increased because of reclamation project. Cd was the strong ecological risk factor. The geoaccumulation index also showed that the pollution degree of heavy metals in is reclamation project was higher than those in Jiuduansha Nature Preserve, mainly account for Pb.(3) The contents of heavy metals in Corbicula fluminea in Corbicula fluminea during the process of reclamation project were analyzed. The results showed that the concentration of heavy metals was Cu>Cd>Pb>As>Hg. The contents of heavy metals of Corbicula fluminea in Pudong airport reclamation project were greater than those in Jiuduansha Nature Preserve. The lowest content of heavy metal in Corbicula fluminea was found in winter. Both Edible evaluation and BSAFs illustrated that Corbicula fluminea had strong adsorptive ability of Cd.Corbicula fluminea were seriously polluted in this area, not eat too much.