Study On The Bioaccessibility Of Heavy Metals In Industrial Shellfish To Human

Shellfish can easily accumulate heavy metals, and heavy metals in shellfish highly depend on the environmental quality. However, economic development has intensifies the pollution of heavy metal in sea waters, especially in coastal waters. It has always been a concern about heavy metals in shellfish as it’s one of the major seafood in China. But the risk that based on total amount of heavy metals in shellfish can also be overestimated due to the total amount does not provide information on its bioavailability. In order to efficiently evaluate the bioavailability of heavy metals and other pollutants, the researchers developed a lot of bionic digestion models, and currently vitro bionic digestion model is increasingly being applied to the fields of environment, food, pharmaceutical, etc. In this study, the technique of bionic digestion and unilammellar liposome are combined to create a bionic digestion model to study the speciation and bioavailability of heavy metals in shellfish, and targeted to provide basic statistics information for the risk estimation of eating shellfish with heavy metals residues, and to promote the healthy development of aquatic products.The results of this study are as follows:(1) Adding digestive enzymes in the digestive juice can increase the solubility of shellfish, and provide better extraction effectiveness to the bionic extraction digest than half bionic digestion. Vitro bionic digestion model for shellfish is more reliable and effective as it’s similar to the shellfish digestive process in human begin.(2) As optimal amount of bionic digestive juice can be changed by different shellfish species, heavy metals, phase of digestion, and some other factors, in order to improve the usability of vitro digestion model full, the experimental compared the extraction effects of five different heavy metals in C. rivulari and R. philippinara during the digest stages of stomach and intestines, and determined the required amount of gastrointestinal digestive juice: gastric juice 150 ml, duodenal juice 200 ml and duodenal bile 80 ml.(3) Different ways of eating shellfish will affect the bio-acceptability of heavy metals in shellfish, but it varies for different heavy metals. Generally, the bio-acceptability of Fe, Zn and Mn in cooked oyster samples is higher than in raw oyster samples, while that of Cd is in the opposite; in clams samples, the bio-acceptability of Zn, Cu in cooked ones is lower than that of raw ones.(4) The measurement of bio-acceptability of heavy metals in C. rivulari and R. philippinarashowed that: when comparing between the different heavy metals, the bio-acceptability of Fe is the lowest(60% and 45%), while that of Zn, Mn, Cu, Cd is more than 80%; when comparing between shellfish, the bioavailability of heavy metals in R. philippinara is relatively lower than in C. rivulari.(5) In the unilammellar liposome- water distribution system, the presence of most heavy metals is in water soluble state, and 90% of the distribution factors are lower than 0.89, only a small portion of the bio-acceptability transformed into absolute bioavailability. Illustrating only a small amount of heavy metals that transferred from the two shellfishes into the digestive juice are absorbed by human, and the heavy metals entering the circulatory system of human body is only a small part of the total amount of heavy metals in shellfish...