Dissertation > Excellent graduate degree dissertation topics show

Safety Assessment of Cadmium Pollution in Aquatic Products and the Research into the Influence of Cadmium in Different Forms

Author: LiMin
Tutor: DiZuoXiu
School: Ocean University of China
Course: Of Food Science
Keywords: Cadmium Inorganic cadmium Organic cadmium Aquatic
CLC: TS254.7
Type: Master's thesis
Year: 2008
Downloads: 161
Quote: 0
Read: Download Dissertation

Abstract

Cadmium is an organism the nonessential harmful trace elements, is also important in the aquatic persistent pollutants. Recent years, with the development of industry and agriculture, the environment and feed cadmium pollution intensifies, pass through the enrichment of aquatic animals and the food chain, human health posed a potential threat, and even affect the export of aquatic products in China. View of this situation, the paper study of cadmium from three aspects: First, select some regions of China with representative aquatic monitoring survey of the heavy metal cadmium content of the pollution situation analysis, and to evaluate its food safety aims to provide a reference for related research and standards cadmium perfect, provide a theoretical basis for the safe to eat, and to provide the basic data for future aquatic health quality monitoring, aquatic standards to develop and perfect, as well as the relevant departments to carry out the appropriate supervision regulators to provide the basis. In this paper, Litopenaeus vannamei targeted, systematic study of different forms of cadmium in feed for aquaculture animals through breeding experiments to compare the differences in the growth of aquatic animals, toxicity and accumulation law to fill such research gaps, limited the development and improvement of the standard of cadmium in the aquatic and aquaculture industry supervision and monitoring, and standards to optimize and improve the limit of cadmium in feed standard form and limited food formulated to provide the technical basis. Is used for the status quo of much-needed form of detection methods Cadmium and its morphology, breeding experiments fodder for the object, according to the nature of the organic cadmium and inorganic cadmium characteristics, the analysis method of cadmium form of extraction system research, this research useful discussion. The next step recommendations made on the basis of analysis of experimental results. Through the study found that the cadmium content of the decimation of aquatic there are regional variations and species differences, the cadmium content of the order of bivalve molluscs gt; shrimp gt; fish. Various regional fish and shrimp cadmium content were within the normal range, food safety is not affected. High cadmium content but some of the shellfish in the individual districts, affected by some degree of food security, should pay attention to. Monitoring results show that the content of cadmium in shellfish than fish and shrimp, but some shellfish liquid, visceral yet excellent fish feed ingredients which further contamination of cadmium in the form of organic Cd shrimp Other farmed aquatic animals. The morphology of cadmium toxicity hazard difference has been the focus of debate at home and abroad, the paper discusses the similarities and differences between the inorganic of cadmium and biological cadmium to farmed shrimp Wen object. Shrimp farming experiments found that farmed 131 days in the same concentration of cadmium, shrimp feed fed organic cadmium group higher mortality, to prove organic cadmium toxicity on aquatic animals may be greater than the inorganic cadmium, which there is a dispute with the traditional view ; compared with the control group, the of inorganic cadmium group feed shrimp growth with increasing cadmium concentrations showed obvious parabolic relationship, the organic the cadmium group of feed with the concentration of cadmium increased the growth of shrimp significantly enhanced role; feed two basically similar to the morphology of cadmium accumulation in the the prawn three organizations law, shrimp body parts cadmium residues add the amount of cadmium in feed and breeding time was positively correlated with the three organizations of the two forms of the same concentration of cadmium in shrimp The growth trend is also similar. Overall, these two forms of cadmium accumulation rate trends in the the Litopenaeus vannamei organizations relative the shrimp shell gt; shrimp offal gt; muscle, but in Litopenaeus vannamei organization the size of the absolute volume trends are shrimp offal gt; shrimp shell gt; muscle. , Inorganic cadmium representing the accumulation of organic cadmium easier Prawn. Visceral the enriched target organ is the shrimp body cadmium accumulation accounted for about 80% of the total body cadmium content. Detection of cadmium form the basis of research, but because it is difficult to separate home and abroad there is no analysis of the in vivo method of this thesis. Were used organic solvent extraction, hydrochloric acid extraction method and water to mention ultrafiltration centrifugation morphological analysis of different forms of cadmium in the feed, the study found that the organic solvent cyclohexane and ethanol can not dip proposed organic feed Cd; organic cadmium in a lower concentration of hydrochloric acid is destroyed dissociate, and can not be confirmed that the specific degree of dissociation; separated according to molecular weight by ultrafiltration using a centrifuge tube, is extremely complex due to the feed ingredients and feed processing production process complex physical and chemical changes occur, the results of theoretical speculation falls far short of low recoveries. In short, the morphological analysis of cadmium in feed, pending further study and testing. Select a suitable extraction system, based on the nature of the characteristics of the different forms of cadmium in the morphology of cadmium is not destroyed under the premise of its morphological analysis of to obtain separation technological breakthroughs is the urgent need to address the key issues.

Related Dissertations

CLC: > Industrial Technology > Light industry,handicrafts > Food Industry > Aquatic products processing industry > Standards and inspection of aquatic products
© 2012 www.DissertationTopic.Net Mobile