Distribution Characteristics Of¹³⁷Cs And Heavy Metals In The Soil Of Guangxi Beibu Gulf

Coastal zone is the most active areas of land-sea interaction and the most sensitive areas for study the human activities and global change. Coastal zone is the key objects for study land and sea interactions. The research area in the thesis is Beibu Gulf in Guangxi, including Beihai, Qinzhou, Fangchenggang, and the building nuclear power plant in the Guangpo town, port area of Fangchenggang. Radioactive nuclide137CS is one of the most important indicator elements in modern sedimentary environment. Heavy metal with high toxicity, environmental persistence, with the accumulation of the food chain or food web features, is considered to be one of the main pollutants in environment. It takes serious harm to the environment. The specific activity of137Cs and heavy metal content in soil samples in the Guangxi Beibu Gulf were measured.The distribution characteristic of137Cs, and heavy metals (such as Cd、Cu、Pb and Zn) were discusses. The main result of the thesis is as follows:(1) The specific activity of Cs in various soil types in Guangxi Beibu Gulf is indicated:paddy> forest land> dry field> grassland≈estuarine bay. In general, the specific activity of137Cs in P01standard section decreases with depth. The deposition rate of San Niang Bay sample column SN2is about0.38cm/a.(2) The distribution of the average content of Cd in Guangxi Beibu Gulf for various types of soil surface samples is indicated:grassland> paddy≈dry field> estuarine bay> forest land. The distribution of average content of Cu、Pb and Zn are:estuarine bay> forest land> paddy> dry field> grassland. Heavy metal in land surface samples, Cd is mild pollution; other elements such as Cu、Pb and Zn are pollution-free. For mild damage on ecological harm, Cd is mild; other elements such as Cu、Pb and Zn are very mild, integral harm is very mild. Heavy metal in gulf surface sample, Cd and Cu are mild pollution, Pb and Zn are pollution-free. For mild damage on ecological harm, Cd is mild, other elements Cu、Pb and Zn are very mild, integral harm is very mild.(3) The content of Cd and Zn in P01standard section, in general, has a fluctuations downtrend with depth increasing, and the content of Cu has a small fluctuations downtrend, and the content of Pb has a small fluctuations uptrend. The polluted effect from different heavy metals as follows. Cd is mild pollution, Cu、Pb and Zn are pollution-free; on the ecological harm, Cd、Cu、Pb and Zn are very mild, integral harm is very mild.(4) Heavy metal elements content in the San Niang Bay sample column SN2changes with the depth is the same trend, generally decreasing with the depth increasing. Cd is mild pollution; Cu、Pb and Zn are pollution-free. For mild damage on ecological harm, Cd is mild, other elements (such as Cu、Pb and Zn) are mild, and the integral harm is very mild.(5) Through the analysis of the distribution characteristics of137Cs, the distribution characteristics of heavy metal, heavy metal pollution and potential ecological risk assessment, in the study area in Guangxi Beibu Gulf, can provides help for the study the soil erosion and accumulation in this area. According to the results, we can obtain basic background data for the future study of the Fangchenggang Hongsai nuclear power plant. The relevant data can provide help for the study of heavy metal pollution in soil as well as the preventive measures in Guangxi Beibu gulf.