Study On The Regularity Of Move, Enrichment, And Translation Of Cadmium And Other Heavy Metals In The District Of The Three Gorges Reservoir

It has been discussed that the distribution characteristics and regularity, geochemical pattern, mineral property, and ecological effects of As, Cd, Hg, Cr, Cu, Ni, Pb, and Zn, etc. in different carriers such as rock, soil, water system sediment, garbage, and sediment deposited from sewage in Chongqing area of the Three Gorges reservoir. This research has special significations for the protection of ecological environment and application of land. Some new cognitions has been gained:1.Compared to the rocks of East China, the geochemical compositions of limestone, mudstone, and sandstone in study area do not show distinct differences, which can only form little influence to the distribution of heavy metals. The background value of heavy metals in soil has been proposed first in study district.2.Two methods, standard contrast and geological cumulation index, have been used to evaluate the degree of pollution of heavy metals in the Three Gorges reservoir. Because the latter method considers the effect of nature background, it has more reliability and can be used as the evaluated method for the pollution of heavy metals caused by the human in the future. The regional pollution of heavy metals in the surface soils is less than the middle degree in the Three Gorges reservoir. It has been found that the cadmium has regional pollutions with light degree and spotted pollution with middle degree. Arsenic has local pollution with light degree and spotted pollution with middle degree. Mercury has local pollution with light degree and spotted pollution with middle and high degree. Chromium, copper, lead, and zinc have only spotted pollution with light degree.3.Upon the section study for longitudinal, horizontal, and vertical direction along the Yangtze river, it can be concluded that the Cd has middle to high degree pollution in the sediment continuously, and Hg and Pb with middle to high degree pollution locally. The pollution of heavy metals in the sediments of Yangtze river system has the characteristics of Cd>>Hg>Pb(Cu)>Zn>As>Ni>Cr. The pollution of Cd in sediment of three Gorges region mainly come from the upper part of Yangtze river, and partly from the urban sewage and garbage.4.The forming states of elements in the sediment are different. Cr, Hg, Ni, and Pb exist as residue, and Cd as carbonate. Cd in state of ion-exchange and easy transference has high proportion, with state of ion-exchange, carbonate, and iron-manganese oxidation up to 63 percent. The chief reason of Cd anomaly in Yangtze river system is that much of Cd exists as state of easy transference and can deposit in proper conditions.5.The content of Cd in the paddy soil with state of dissociation and easy...