| After entering into water environment, low concentration of mercury hard be degraded by biology, which can be accumulated in the food chain by organisms and transformed into organic form to harm people’s health and Guangxi Beibu Gulf has unique geographical position and complicated marine environment. The intertidal zone is the typical transitional zone of Combination of coastal geomorphology and river flow, habitat and breeding sites of offshore seashells, fishes and many kinds of endangered wild lives and typical environmental vulnerable areas and sensitive zone as well.In this paper, we choose intertidal zone of Guangxi Beibu gulf as research area.In 13 sampling stations, the study objects related to can be divided into 3 categories:molluscs, arthropods and sipuncula, which including 20 kinds of shellfish, 6 kinds of intertidal crabs and 1 kind of Sipunculus in terms of specific types.And then we measured total mercury concentration of 27 kinds of organisms and the surface sediments of the intertidal area, and investigatd the mercury enrichment characteristics in different parts of intertidal crab and bivalve mollusks of some stations with the DEM-80 solid and liquid phase of direct mercury analyzer, and last evaluated,in the study area, the biological edible risk of some biological and the potential ecological risk of surface sediments. The research results showed that:1. The average value of mercury content in 13 stations of the collected organisms of Guangxi Beibu Gulf intertidal zone is 16.12ng/g, and the minimum value and maximum value appears in the Meretrix meretrix of Maowei Sea and the Uca dussumieri of Beilun River estuary respectively. The average total mercury content range of 26 kinds biological organisms from 5.16 ng/g to 76.07ng/g, in which the highest average mercury content is 76.07ng/g of Uca dussumieri, and the least in Meretrix meretrix and Monetaria moneta is 5.16 ng/g and 6.29 ng/g respectively. Total mercury content in various organisms were lower than the standard mercury limit in China and related international indicators.2. Based on the classification of various kinds of organisms in the study area,we analyse the mercury content characteristics among biological species that appeared inat least five stations. The data shows that the content of mercury in diverse category is different, mercury concentration among different biology category manifests that Grapsidae > Mytilidae > Ostreidae > Arcidae > Sipunculidae > Veneridae.3. To analysis the mercury content distribution characteristics in different tissues of intertidal crabs of 13 stations and 8 kinds of bivalve mollusks in National Mangrove Nature Reserve(S13), the finding shows that mercury enrichment in the visceral mass were greater than that of other tissues, which indicating that the visceral mass is the major enrichment part of mercury.4. In researching area, the difference of mercury content exists in surficial sediments of the intertidal areas. In terms of different sea areas,the mean value of mercury content range of Fangchenggang, Qinzhou and Beihai offshore areas is 25.15ng/g to 88.43ng/g, 41.28 ng/g to 126.50 ng/g and 36.19 ng/g to 110.71 ng/g respectively, the spatial distribution characteristics of average mercury content display that Qinzhou intertidal areas(S5, S6, S7, S8) > Beihai intertidal areas(S9, S10, S11,S12, S13) > Fangchenggang intertidal areas(S1, S2, S3, S4).5. Employing the single factor index method, hazard quotient method and the method of potential ecological index to evaluate all organisms and sediments.According to the analysis, the environmental pollution of various biology in intertidal zone of Guangxi Beibu Gulf at the level of non pollution which dues to exposed under mercury pollution, and potential human consumption health hazards are generally low, potential ecological risk of surface sediments in study field are at a mild level, in which potential mercury risk of station S5 and station S9 are close to low pollution level. |
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