RESUMO
Objective To investigate the status of cadmium contamination in commercially sold aquatic products and to analyze the risk of dietary intake of cadmium among residents in one district of Shanghai. Methods Multistage sampling was used to collect 397 animal aquatic products from agricultural markets and supermarkets in 11 communities (townships), the District from 2018 to 2019.Cadmium content was tested according to national standard.The status of cadmium contamination was assessed by single factor pollution index(Pi)method.Risk of dietary intake of cadmium among residents was assessed by point evaluation method in combination with food consumption and dietary survey in 2013 and calculation of safe limits for cadmium in various aquatic diets(MOS). Results The detection rate of cadmium was 75.06% in the 397 animal aquatic products and the content of cadmium in 10 samples which crabs were totally exceeded the standard, accounting for 2.52%.The average contents of cadmium in crabs, bivalves which were higher than in shrimps(11.0 μg/kg), gastropods(7.6 μg/kg) and marine fish(3.8 μg/kg) were respectively 140.0 μg/kg and 90.0 μg/kg(χ2=186.41, P < 0.005), but no cadmium was detected in freshwater fish.The single factor pollution index(Pi) of crabs was 0.280 which meant light pollution and the Pi of other kinds of aquatic products was respectively under 0.100 that meant no cadmium contamination.The consumption of animal aquatic products was the highest in freshwater fish followed by shrimps, marine fish and crabs.The MOS of every kind of aquatic products is higher than 1 which meant cadmium intake from commercially sold animal products was an acceptable health risk for the population. Conclusion The risk level of cadmium intake by residents in the district through commercially sold animal aquatic products is relatively low, but the cadmium pollution status of commercially sold crustacean crabs should be vigilant, and the intake of crabs is advised to be reduced as far as possible.Relevant departments should also pay attention and strengthen monitoring and management in this regard.
RESUMO
Both total proteome and differential proteins were effectively extracted, separated and selected by a combined approach of both differential centrifugation and 2D-PAGE in liver of Paralichtys olivaceus( POL) under the stress of cadmium chloride as an artificial pollution source. Approximately 800 spots for extraction of whole protein separated with 2D-PAGE were obtained by direct lysis in the POL. In addition, approximately 11 differential proteins in POL were also obtained under the stress of cadmium chloride. The differential centrifugal were used to prepare three sedimentation and a plasmolysis proteins, called POL component Ⅰ, POL component Ⅱ, POL component Ⅲ, and POL component Ⅳ(plasmolysis protein), respectively. Total protein spots for each gel were calculated to have 380, 550, 500, and 850, respectively, approximately 2280 spots in sum, while total spots are much higher than those by direct lysis approach. Using the comparison method, approximately 54 differential proteins in POL were obtained by a combined technology of both differential and two dimensional polyacylaminde gel electrophoresis(2D-PAGE) methods under the stress of cadmium chloride. In addition, these differential proteins can be further identified by peptide mass fingerprint(PMF). Here, these combined techniques can be effectively used to extract, separate and identify the whole proteins and the differential proteins including protein markers in the biological tissue.