| With the rapid development of coastal industries of Jiangsu Province,heavy metal pollution to coastal environment has aroused wide attention.Heavy metal accumulation happens in the body of shellfish and can be transferred to human body through food chains and then lead to potential risks of edible safety.The coastal Jiangsu people’s consumption of shellfishes has been investigated in this thesis.According to the gender,age and body weight,we selected the inhabitants in Jiangsu coast area(Ganyu,Jianggang and Yangkougang)for questionnaire test from June to October in 2015,considering the different factors such as their likeness to shellfishes,frequency to eat and their consumption amounts per time.At the same time,we has collected four kinds of sample shellfishes from 12 coastal stations of Jiangsu Province,analyzed the feature of lead and cadmium concentration in shellfishes,and fullfiled the exposure assessment and the risk assessment.Results are showed as follows:1.The most consumption of the shellfishes was focused on the adults with the body weight ranging from 50-65KG.They consumed the shellfishes 3-5 times per week,and ate 10-50 g each time.Their preference for Meretrix meretrix topped the list,followed by Ruditapes variegata.Mactra venerifonnis and Cyclina sinensis took the third and fourth place respectively.They are used to buy shellfish from aquatic products wholesale market and farmers’ market taking freshness and price as their major purchasing factors.2.Atomic absorption spectrophotometry was used to research the feature of lead and cadmium concentration from 2012 to 2015 in the four economic shellfishes mentioned above collected from Maojia Port,Yangkou Port and Changsha Port of Jiangsu Province.The results revealed that lead concentration in the sample shellfishes ranged from 0.02-0.77 mg·kg-1 with an average of 0.25 mg·kg-1 and 100%pass rate.From 2012 to 2014,average lead in the sample shellfishes was listed from high to low as Mactra veneriformis,Meretrix meretrix,Ruditapes variegata and Cyclina sinensis,while in 2015 it was Meretrix meretrix,Mactra veneriformis,Ruditapes variegata and Cyclina sinensis.Cadmium concentration in sample shellfishes ranged from 0.05 mg·kg-1 to 0.83 mg·kg-1,with an average of 0.30 mg·kg-1 and 100%pass rate.From 2012-2013,average cadmium in the four types of shellfishes in descending order was Meretrix meretrix,Ruditapes variegata,Mactra veneriformis and Cyclina sinensis,in 2014,it was Ruditapes variegata,Meretrix meretrix,Mactra veneriformis and Cyclina sinensis,and in 2015,it was Meretrix meretrix,Ruditapes variegata,Mactra veneriformis and Cyclina sinensis.Cadmium and lead concentration were varied in different organs of the sample shellfishes.Visceral mass had the highest level of lead amount,followed by gill and mantle,and shell the lowest.3.After comparing lead and cadmium concentration in the sample shellfishes of March,2015,it could be seen that differences were existed in data from different stations.Lead reached the highest point at station Chen Jiagang Port to 0.44 mg·kg-1,while Yangkou Port has been found the lowest to 0.21 mg·kg-1.For cadmium concentration,station Chen Jiagang Port owned the highest to 0.37 mg·kg-1,while Dongsha fell as the lowest to 0.09 mg·kg-1.Those,which were accompanied with high lead and cadmium,were mostly located in coastal areas with chemical industries.4.Statistics,from September of 2012 to August of 2013,collected from the sample shellfishes,showed that season changes would result in lead and cadmium concentration change in shellfishes.The highest lead points of all the four type shellfishes--Meretrx meretrix,Cyclina sinensis,Ruditapes variegata and Mactra veneriformis--appeared in summer as 0.77,0.12,0.23 and 0.61 mg·kg-1 respectively,and as for the highest cadmium point,they would present in autumn as 0.83,0.20,0.27 and 0.24 mg·kg-1 respectively.Both the lowest lead points(0.13,0.02,0.08 and 0.20 mg·kg-1)and the lowest cadmium points(0.31,0.08,0.16 and 0.12 mg·kg-1)for the sample shellfishes were not sure when would be the exact month.5.Edible safety risks to the lead and cadmium concentration in the sample shellfishes have been assessed through single factor pollution index.The results indicated that all the four kinds of shellfishes were within the limits of China’s pollution free products,and could be provided to the dinning table.The average Pi index of Cyclina sinensis in both lead and cadmium concentration was the lowest,which suggested that among above four kinds,Cyclina sinensis was the least contaminated by lead and cadmium.Meretrix meretrix,Ruditapes variegata and Mactra veneriformis from Chen Jiangang Port and Yangkou Port suffered slight pollution during some months.Generally speaking,however,all of them were well satisfied with the requirements of food safety.6.Exposure assessment to the four kinds of economic shellfishes was taken through Point Assessment and Target Hazard Quotient..It showed that exposure for weekly intake of lead and cadmium,to all the sample shellfishes,was under the level of PTWI and the THQ of lead and cadmium concentration in each sample shellfish was far blow the threshold,which demonstrated in general lead and cadmium concentration in those four shellfishes would pose low risk over human body.Crystal Ball was adopted to conduct exposure assessment and risk assessment to lead and cadmium intake from shellfishes by seaside people of Jiangsu Province.Its results suggested that coastal people would not suffer high health risks in accordance to the exposure of lead and cadmium intake. |
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