Analysis And Evaluation Of Heavy Metal Pollution In The Major Seafood Of Zhoushan Fishery

Background:People's living standard is improved gradually with the rapid development of economy and society, and the food safety has become the focus, but people paid not enough attention to the heavy metal pollution in seafood. This article studies the heavy metal pollution status of Zhoushan fishery through the analysis of Lead, Cadmium, Methylmercury content in the main seafood, and provides the scientific basis for health supervision.Materials & Methods:The article analyzed and evaluated the heavy metal pollution in seafood of Zhoushan fishery by reviewing relative data and literature combined with experimental data. According to the distribution of Zhoushan fishery, we randomly selected a certain number of Zhoushan seafood as research object from four county's (district) agricultural products markets. Seafood mainly included sea fish, seawater crustaceans, seawater soft-bodied animals, sea algae. Seawater fish included hairtail, yellow croaker, silver pomfret, etc. Soft-bodied animals included WenGe, scallops, abalone, etc. Crustaceans included crabs, shrimp, etc. The sea algae included laver, kelp, etc. The inedible parts of all the seafood were removed, such as head, shell, organs and scale, and then the samples of the edible parts were grinded into homogenate. We measured the content of Lead, Cadmium using graphite furnace atomic absorption spectrometry method and the content of methylmercury using gas chromatography (acid extraction method of mercaptoacetic cotton). Data of 2007-2009 were analyzed using SPSS.Results:1. The average rates over standard are respectively, Lead 3.90%(11/282), Cadmium 11.35%(32/282), methylmercury 2.84%(8/282).2. Analysis of the Lead, Cadmium, methylmercury accumulation in different types of seafood.(1) The comprehensive evaluation results of the metal content:seaweed (0.4513 mg/kg)>marine molluscs (0.1155 mg/kg)> marine crustaceans(0.0486 mg/kg)>sea-fish (0.0419 mg/kg)(2) Single-factor variance analysis results of the lead, cadmium, methylmercury accumulation in different types of seafood:Lead F=35.683, P<0.001; cadmium F= 25.301, P<0.001; methylmercury F=25.990, P<0.001.(3) Comparison results:Scheffe method:Lead accumulation:seaweed-sea fish (P<0.001), seaweed-sea mollusks (P<0.001), seaweed-sea water crustaceans (P<0.001) difference between the statistical significance. Cadmium accumulation:sea fish-sea water molluscs (P<0.001), sea fish-algae (P<0.001), marine molluscs-marine crustaceans (P=0.0019), marine molluscs-seaweed (P=0.0083), the sea crustaceans-seaweed (P<0.001) difference between the statistical significance. Methylmercury accumulation:seaweed-sea fish (P <0.001), seaweed-sea mollusks (P<0.001), seaweed-sea water crustaceans (P<0.001) difference between the statistical significance.S-N-K law:Lead accumulation:According to a= 0.05 level, sea-fish, sea molluscs, sea crustaceans three kinds of seafood, the overall average level of lead accumulation are not significantly different; but seaweed accumulation of lead in the overall average level of the above-mentioned three kinds of seafood are statistically significant. Cadmium accumulation:According to a=0.05 level, the sea of fish, crustaceans, difference between two kinds of seafood, seawater cadmium accumulation and the overall average was not significant; but water mollusks, seaweed accumulation of cadmium in the overall average level of the two kinds of seafood have a statistically significant difference, and the water molluscs, seaweed accumulation of cadmium in the overall average is also statistically significant. Methylmercury accumulation:According to a=0.05 level, it is not that the sea-fish, sea molluscs, sea crustaceans three kinds of seafood, the overall average level of methylmercury accumulation are different; but seaweed accumulation of methylmercury overall average level and the above-mentioned three kinds of seafood, there are statistically significant.3. Safety analysis of different types of seafood in the lead, cadmium, methylmercury food(1) Single-factor pollution index method:Lead single pollution index values are: seaweed (0.53)>marine crustaceans (0.28)>sea-fish (0.24)>marine molluscs (0.16), all seafood, the body of lead pollution index values are less than 1, indicating both still clean. Cadmium single pollution index values are:seaweed (1.22)>marine molluscs (0.64)> sea-fish (0.21)>marine crustaceans (0.07), can be seen, seaweed has been subjected to moderate pollution, while the other seafood free from contamination, but water pollution in the software category index also reached a high level. Methylmercury single pollution index values are:seaweed (0.38)>marine molluscs (0.11)>sea-fish (0.10)>marine crustaceans (0.08).(2) Chi-square test:Lead x2=10.167, P<0.05; cadmium x2=62.940, P<0.001; methylmercury x2=20.960, P<0.001.(3) Comparison results:Lead:water molluscs-seaweed exceeded different. Cadmium:Sea fish-sea water molluscs, sea fish-seaweed, sea molluscs-marine crustaceans, sea molluscs-seaweed, sea crustaceans-seaweed different. Methylmercury: Sea Fish-seaweed, sea molluscs-seaweed, sea crustaceans-seaweed different. 4. Seafood in different years of lead, cadmium, methylmercury accumulation ComparisonKruskal-Wallis rank sum test results:Lead the approximate H-statistic significant probability value 0.000; cadmium approximation of H-Statistics significant probability value of 0.694; methylmercury H-statistic is a significant probability of the approximate value of 0.076.Spearman correlation test results:P= 0.000 lead, cadmium P= 0.974, P=0.024 methylmercury.5. Safety assessment of different years of lead, cadmium, methylmercurySeafood in different years of lead, cadmium, methylmercury exceeding the rate of x2 test results:Lead x2=6.440, P<0.05; cadmium x2=34.455, P<0.001; methylmercury x2 =5.226, P> 0.05.Conclusions:1. Heavy metal pollution in different kinds of Zhoushan fishing is different. The algae is the worst, the second is seawater soft-bodied animals, and sea fish, sea water crustaceans pollution most light;2. Lead, and methylmercury mainly pollutes sea algae seafood, Cadmium mainly pollutes sea algae, followed by seawater software class.3. The rates over standard of different kinds of seafood are different from each other, while the rates over standard of Lead, Cadmium, methylmercury in sea algae are all the highest.4. Evaluated by pollution index, lead, methylmercury pollution is still low, cadmium in the sea with mild pollution in algae seafood.5. In the recent three years, heavy metal lead pollution in seafood is tending to be worsened, while the cadmium, methylmercury pollution levels remain basically stable.