Speciation Analysis And Environmental Assessment Of Trace Mercury In Soil In Shihezi Region

Mercury is a highly biological toxic metal element.The impact of mercury pollution on the environment has been great concerned since the Japanese Minamata disease.With the continuous development of the western region,a number of high-polluting,high energy-consuming enterprises settled in the "Gobi Pearl" Oasis Shihez.However,the basic research on mercury pollution in concentrated areas of chlor-alkali production and coal-fired power generation is still in the lack of stage,and it is urgent to carry out research on the pollution characteristics of soil mercury in the area,and provide theoretical support for soil mercury control.In this paper,we researched the soil of alkali chemical and coal-fired power plants in Shihezi.The distribution of mercury content in soil,the distribution of morphological characteristics,the characteristics of adsorption and desorption of typical soils and the environmental assessment of soil mercury pollution were carried out..The results will guide the control of soil pollution in arid areas,and will also be of reference value for the research and comprehensive control of environmental mercury pollution in northwest China.The main conclusions are as follows:The mercury content in the Shihezi urban area is 0.001 mg·kg-1-0.902 mg·kg-1,the average is 0.176 mg·kg-1,which is much higher than the Xinjiang background(0.017mg·kg-1)but is lower than the national secondary standard(1.000 mg·kg-1).At the same time,soil mercury content monitoring was carried out in Shawan and Manas areas around Shihezi.The soil mercury content in the sandy area is 0.001 mg·kg-1-0.491 mg·kg-1,with an average value of 0.102 mg·kg-1;the mercury content in the Manas area is 0.046mg·kg-1-0.882 mg·kg-1,the average value of 0.286 mg·kg-1,higher than the average mercury content in Shihezi soil;Bioavailability analysis showed,species mercury from Shihezi soil samples could be used by plants and animals was less,but the more potential bioavailability.The results showed that the higher the total mercury content in the soil,the higher the total organic content of the soil,the higher the content of refractory organic matter and the mercury content of the residual organic matter.Organic matter was associated with easily degradable organic matter,refractory organic-bound mercury and residual mercury content showed significant positive correlation.The adsorption and desorption of mercury in the three soils showed that the maximum adsorption capacity of mercury in the three soils was the largest in the meadow soil,followed by the fluvo-aquic soil and the grey desert soil.The effect of organic matter on the adsorption and desorption of mercury was studied.The results showed that the lower the content of organic matter in soil environment,the more desorption of mercury in soil.The soil adsorption kinetics experiment shows that the adsorption rate of fluvo-aquic soil was the largest,the adsorption rate of meadow soil was the second,and the adsorption rate of grey desert soil was the smallest.The FTIR spectra of soils and their complexes with mercury showed that the adsorption occurred mainly in O-H,C-O and C = O or C = N groups.The environmental mercury risk assessment of urban soils showed that the change of mercury release in urban areas was very small and had little effect on the overall environmental quality of urban areas.The overall pollution level of Shihezi was non-polluting or mild pollution,and it was within the national soil environmental standard.Risk Health Assessment found that the health risks of soil mercury got into the human body with three methods(Ingestion/Dermal absorption/Respiratory)were lower than normal.