关键词: 汞; 重金属污染; 赋存形态; 风险评价; 珠江流溪河; 广州;

Abstract: In the process of urban industrialization,soil heavy metal pollution has gradually attracted attention of many researchers.Taking the area along the Pearl River-Liuxi River in Guangzhou as study area,a total of 66 surface soil(0-20 cm)samples were collected in the study area in September 2016.Total mercury and the content of different occurrence forms of mercury in the collected soil were detected and analyzed by using the Tessier continuous extraction method,combined with cold atomic absorption spectrometer(CVAAS)and the Atomic Fluorescence Spectrometer(AFS).The analysis results show that the total mercury content in the soil of the study area is in the range of 0.029～4.496 mg/kg,of which the over-standard rate of Hg in soil sampled from agricultural land is 17.39%,the contents of Hg collected from construction land are all less than the standard limit and the high distribution areas are mainly concentrated in the park area.In addition,it is found that the mercury element in the soil mainly exists in the form of residue through comparative analysis,followed by the organic binding state,and the iron manganese oxide binding state is the least.Based on the results of the risk assessment,it can be judged that the study area is generally at a slight ecological risk level.The research results can provide certain reference for guiding the pollution control of mercury in the soil.

Key words: mercury; heavy metal polutants; occurrence form; risk assessment; Liuxi River of Pearl River; Guangzhou City;