Study Of Fish Mercury Content In Nanning Market And Yongjiang River

Mercury is hazardous and toxic metals to living creatures, and Methylmercury is even more harmful. The mercury in the aquatic environment will gradually gather in the body of fish through bioaccumulation. Fish is one of human food sources, while fishes with high mercury levels inside can cause harm to the health of human body. With the ever social progressing and economic development, more and more food safety problems aroused people's attention. Nanning, as a southern city of China, is of a high-level fish consumption. So it is very important to conduct a research on the mercury content of fish on the market and Yongjiang River, which also has a great significance for evaluating mercury exposure safety when dining fishes.In this paper, we choose Yongjiang River and several large farmers' markets as study area, combining field surveys and laboratory analysis together by using U.S. EPA 7473 Method and DMA-80 Direct Mercury Analyzer in 10 Nanning Markets with 6 kinds of fishes. It takes 7 sampling sites in Yongjiang River with 12 kinds of fishes and 11 sites with sediments so as to improve the experimental process and quality control and also has assessment with fish intake safety and potential ecological risks of sediment.The results show that: 1. the total mercury content in fish market ranges between 3.15ng/g to 79.71ng/g, with an average value 19.35ng/g, a median 11.64ng/g. Total mercury level of fish in Yongjiang River ranges from 2.10ng/g to 330.56ng/g, with an average of 44.18ng/g, a median 29.53ng/g. Fish mercury in Yongjiang River is slightly higher than that of the market, both medians of mercury level values are below average ones, indicating lower level of mercury in most fishes, and both two items are below the limits prescribed by the State Food Safety Total mercury levels in freshwater fish—500ng/g. Fish total mercury content in a safe range. 2. On different nutrient levels mercury content is varying in fishes categories, Yongjiang water environments: herbivorous <omnivorous <filter-feeding fish. 3. The body length, weight and content of THg correlation analysis shows that most of the fish has no significant correlations, only the market tilapia fish mercury levels in fish body length has a negative correlation; In Yongjiang River, Wo flower carp fish body length and weight is positively correlated with the mercury content, tilapia fish mercury levels in body has a negative correlation with weight. 4. According to the single factor index method, WHO and FAO PTDIs acceptable daily intake can evaluate safety of fish, indicating that most of the fish Hg potential harm to human body is very small in Nanning market and Yongjiang River, and sensitive populations should be careful about excessive intake bighead carp, silver carp and blue saury. 5. The sediments of Yongjiang river spatial distribution of mercury are characterized with higher in middle and lower in east and west for the fact that Yongjiang River has various pollutants by tributaries flowing through the city. The higher place of mercury levels in Yongjiang River is located in Shuitangjiang River and Bachijiang River junction. Use of the Potential Ecological Risk Index indicates smaller potential ecological risks of mercury in Yongjiang River sediments based on the average of the Pearl River Basin sediments mercury content, but mercury loads into the Yongjiang River Estuary need to arouse enough attention.Overall, commercial fish and Yongjiang River aquatic environment mercury loads are small, the mercury content of fishes are below the national limit standard within a safe edible range. By discussing the origin of the fish, the feasibility of establishing a mechanism for the origin on the food safety is a question for us to answer. When food quality and safety problems happen, you can use experiment and analysis tools in combination with other methods to determine the source of contamination of food.