The Variance Characteristic Of Heavy Metals In The Lower Reaches Of The Huanghe And Sediments Of Estuarine Wetland

Heavy metals as environmental pollutants, due to its special chemical and geochemical properties, and the toxic effects, have been attracting widespread attention. Estuarine wetland is a typical complex system of non-steady state. It is coupling bolt of the interaction of many factors, such as runoff, ocean, atmosphere, biological, geological processes and human activities. Estuarine and tidal flat environment is not only unique function and ecological value, but also rich in land resources. Because of various functions, tidal flat become the focus of the many problems. This paper focuses on the variance characteristic of heavy metals in the lower reaches of the Huanghe and sediments of estuarine. The influences of heavy metals in water and sediment were discussed. The achievements can enrich the understanding of coastal wetland biogeochemistry. And it also can provide a reliable scientific basis for management, protection and pollution control of Huanghe estuary wetlands.Yellow River wetland sediment samples in this study were collected in April 2009 (spring), June (summer). Dissolved and particulate samples were collected from the low reaches of Huanghe from December 2008 to November 2009. Concentrations of Cu, Pb, Zn, Cr, Cd, As, Hg of all samples were determined. The distribution and influencing factors of heavy metals were studied1. The average concentrations of Cu, Pb, Zn, Cr, Cd, As, Hg in surface sediments of the Huanghe estuary wetland are 22.1,53.8,78.4,60.5,0.25,7.7,0.055μg/g. The average concentrations lie lower range for other regions. Except Pb, all heavy metals meet National environmental quality standard for soils. Concentrations of heavy metals in spring are higher than in summer. Concentrations of heavy metals in surface sediments exist spatial differences. The difference is mainly due to different hydrodynamic and the environment.2. Concentrations of heavy metals of core sediments changed greatly, and it was peak-like distribution. Because of early diagenesis, concentrations of nearly all heavy metals of core sediments increase with depth first and then decrease at stations near the river. Hydrodynamic conditions, Organic matter and vegetation are important factors in vertical distribution.3. Seasonal Variance of concentration of total heavy metals in the lower reaches of the Huanghe is significantly. The range of concentration of dissolved Cu, Pb, Cr, Cd, As and Hg are 1.07-3.18,0.14～0.47,0.13～0.24,0.17～0.39,1.39-2.12, 0.11-0.14μg/L. The particulate heavy metal are 0.45-7.33,0.36-4.01,0.36-5.32, 0.005～0.082,0.02-0.41,0.002-0.025μg/g. Particulate heavy metals are mainly in all these heavy metals. All particulate heavy metals take on a significantly negative correlation between concentrations and discharge, suspended particulate matter. They are the important factors to effect the seasonal variation of particulate heavy metals. Huanghe input about 24.02 tons of dissolved Cu,4.11 tons of dissolved Pb,2.22 tons of dissolved Cr,3.81 tons of dissolved Cd,24.59 tons of dissolved As, and 1.60 tons of dissolved Hg to the Bohai Sea every year. Huanghe input particulate Cu, Pb, Cr, Cd, As and Hg about 406.07,334.14,350.46,5.11,21.19,1.65 tons to the Bohai Sea every year.