Study On Contents And Speciation Of Arsenic In Four Bivalves And In Vitro Bioaccessibility

Marine bivalves, such as mussel, oyster, razor clam, clam, have a lot of protein, fat and microelement, and so on. They are one of kinds of edible marine foods of inhabitants in the coast of our country. Nevertheless, Bivalves have such an ability of enriching arsenic in seawater and other environment substance that arsenic content in them is much higher than biological source food in land. Arsenic in bivalves is divided into inorganic arsenic and organic arsenic. When they enter human body followed by food, excerpt some of them excreted quickly through urine and feces, plenty of them, especially inorganic arsenic, are accumulated in vivo and will be potential human health risk. So it is very important and necessary to efficiently control and analyze arsenic pollution of marine foods in their growing environment and artifactitious process.The ways arsenic entering human bodies, except respiration of lung in occupation, usually are hand-oral and gastrointestinal way by ingesting foods and water which has being of great interest in researchers of many countries. Many researchers from some countries have taken more and more attention on accumulating and health risk of arsenic in food to people, especially to children. This study is about the solution and transfer of arsenic in four bivalves by method of in vitro bioaccessibility. It has a great signification to farther study how arsenic in high-arsenic food can change and release from matrix and whether it will transfer from one speciation to another in human gastrointestinal track.In our study two parts of arsenic problems will be discussed.1 Speciation and content of arsenic in four marine bivalves of Zhejiang province coast districts. The collection of four bivalves was done. Total arsenic of bivalves were treated with microwaving digestion method and determined by hydride generation-atomic fluorescence spectrometry (HG-AFS). Compare of the two treat methods, microwaving and ashing digestion, was conducted to find the best one. The results showed microwaving digestion is more convenient, quickly and timesaving and finally was selected in this study as the treat method. Inorganic arsenic of bivalves was treat with 1:1 hydrochloric acid and determined by HG-AFS. Though the contents of arsenic in the four bivalves are much higher than common land source food, the content of inorganic arsenic is not excess to the limits standard of food health of China. The district difference existed in the content of total and inorganic arsenic in bivalves. The contents of total and inorganic arsenic of the same bivalve were also compared. Seawater and sediment were collected in the bivalve growing districts and their contents of arsenic also were determined and compared to those of bivalves.2 The method of in vitro bioaccessibility was established to determined the capability of solution of bivalves in gastrointestinal track. After bivalves were digested in gastrointestinal track, the contents of arsenic in the digestion fluid wereanalyzed. Arsenic in gastrointestinal fluid is not completely dissolvable. Bioaccessibility of total arsenic was below 70%. Inorganic arsenic increased after gastrointestinal digestion. It is possible that some organic arsenic transferred into inorganic arsenic. The contents of total and inorganic arsenic in raw and cooked bivalves were compared and resulted no great difference. The absorption of arsenic in the cooked was much easier than that of the raw.