| Intertidal is in the marine-terrestrial interlaced zone,it's a bond which connect the land and ocean ecosystem, nitrogen pollutant and heavy metal pollutants are the main pollutant in the estuarine intertidal area. In this paper, the sediments derived from estuaries of the four rivers(Dalinghe?Xiaolinghe?Shuangtaizihe?Liaohe) which inflow into the Liaodong Bay and the soils derived from the paddy field?corn field and reed wetland near the Dalinghe. potentiometry was used to determine soil p H, gravimetric method was used to determine soil soluble salt, suspension culture method was used to determine soil nitrification potential, anaerobic sludge culture method was used to determine soil denitrification potential, gas inhibition method was used to determine soil nitrogen transformation, atomic absorption spectrometry was used to determine soil heavy mental.The results of the study were as follows:Study on soil nitrification potential and denitrification potential of sediments and the nearby soil. The four different estuarine sediments differed greatly in nitrification and denitrification potential, nitrification potential decreased in the order of Xiaolinghe>Shuangtaizihe>Liaohe>Dalinghe, denitrification potential following a decreasing order of Liaohe >Shuangtaizihe>Xiaolinghe >Lalinghe in denitrification potential. Among the soils under different land near the Dalinghe estuarine,the nitrification potential of the soils derived from the paddy field?corn field and reed wetland were higher than the Dalinghe sediment's, the denitrification potential of the soils derived from the paddy field were far higher than the other regions'. Among the soils under different land near the shuangtaizihe estuarine, the nitrification potential of corn field is the highest, the denitrification potential of corn field and reed wetland were far higher than the sediment's. both the p H and soluble salt were related to the nitrification and denitrification potential, positive correlation were observed between the p H and nitrification potential, but the soluble salt had negative correlation with nitrification potential.both the p H and the soluble salt had positive correlation with the the denitrification potential.Study on nitrogen transformation in the sediments of the Liaohe's estuarine. With the presence of the air, the oxygen and argon gas, nitrification?denitrification?anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium would happen. the nitrification easier happened under the condition of air and oxygen, the nitrification potential is higher than the denitrification potential. the nitrification was far more competitive than anaerobic ammonia oxidation by using the NH4+-N. the aerobic conditions and increasing of NH4+-N content were beneficial to the nitrification, anaerobic conditions was beneficial to the denitrification, the presence of NH4+-N and NO3--N substrate were beneficial to the anaerobic ammonium oxidation.Assessment on heavy metals pollution of intertidal sediments and the nearby soil. the Cu and Zn contents were below the secondary standard of the soil environment quality standard(GB 15618-1995). except the corn field of the Shuangtaizihe estuarine,Cr contents were below the secondary standard. results indicated that the Cu?Zn and Cr hadn't reached pollution levels with the single pollutant index method; the nemerow comprehensive index method was evaluated in the studied area, it showed that the reed wetland near Dalinghe estuarine?the paddy field near Shuangtaizihe estuarine and the sediment in Liaohe estuarine belonged to the light pollution area, other regions hadn't been polluted. the potential ecological risk index was employed for the assessment, the results showed that a single level of potential ecological risk of heavy metals following a decreasing order of Cr > Cu >Zn, the potential ecological risk of metals wasn't high in Liaodong Bay. according to the geo-accumulation index, it showed that the heavy mental pollution following the order of Cr > Cu >Zn. evaluating the potential biological toxicity of Liaodong Bay, it showed that potential adverse biological impacts of Cr is great, but the Cu and Zn isn't great.the biological toxicity following a decreasing order of Cr > Cu >Zn, the assessment of biological toxicity risk and the geo-accumulation index were similar. |
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