Research On Lead,Cadmium,Mercury And Inorganic Arsenic In The Fresh Seafood Of Rizhao City Market From 2013 To 2015

[Objective]As people's living standards improved,food safety issues are becoming more and more concerned by the society.Fresh seafood is rich in nutrition and delicious.It has always been an indispensable food on the table.In order to master the pollution status of lead,cadmium,mercury and inorganic arsenic in the fresh seafood of Rizhao city market.This study was taken in 2013,2014,and 2015,respectively,to collect live and fresh seafood from the city of Rizhao.The contents of lead and cadmium were determined by the graphite furnace atomic absorption method,and the contents of mercury and inorganic arsenic were determined by atomic fluorescence method.The safety analysis was carried out to provide reference for people's diet.[Methods]1.Sample collectionOn the basis of the investigation,20 markets were chosen as the sampling points according to the principle of random.The collection of economic variety common in this property was divided into four categories:sea fish,cephalopods,crustaceans and bivalves.After collection,the sample was numbered and sorted.2.The determination methodThe samples were processed according to the national standard method and then measured.The content of lead and cadmium was determined by graphite furnace atomic absorption method;and the concentration of mercury and inorganic arsenic was measured by the atomic fluorescence.[Results]1.The qualified rate of lead,cadmium,mercury and inorganic arsenic in fresh seafood sold in market of RizhaoFrom 2013 to 2015,there were 851 seafood tested and the total qualified rate was 95.77%.The qualified rates were respectively,lead 99.53%,cadmium 95.08%,mercury 100%,and inorganic arsenic 100%.2.Analysis results of lead,cadmium,mercury and inorganic arsenic in different types of seafood2.1 Content comparison of lead,cadmium and mercury and inorganic arsenic in different types of seafoodThe average value of lead content in sea fish,cephalopods,crustaceans and bivalve seafood was 0.084 mg/kg,0.120 mg/kg,0.116 mg/kg and 0.196 mg/kg;the average value of cadmium content was 0.018 mg/kg,0.378 mg/kg,0.114 mg/kg and 0.817 mg/kg;the average value of mercury content was 0.033 mg/kg 0.042 mg/kg,0.036 mg/kg and 0.072 mg/kg;the average value of inorganic arsenic content was 0.018 mg/kg,0.088 mg/kg,0.022 mg/kg and 0.170 mg/kg.Single factor variance analysis of lead,cadmium and mercury,inorganic arsenic content of four types of seafood:lead F=23.381,P<0.01;cadmium F=31.841,P<0.01;mercury F=18.749,P<0.01;inorganic arsenic F=20.552,P<0.01.2.2 Analysis of qualified rate in different types of seafoodAmong the different types of seafood,the qualified rate of sea fish was 98.58%,the qualified rate of cephalopods was 100%,the qualified rate of crustaceans was 98.13%,and the qualified rate of bivalves was 91.16%.The qualified rate chi-square test of four types of seafood:?2=33.83,P<0.01.3.Analysis results of lead,cadmium,mercury and inorganic arsenic in different years3.1 Content comparison of lead,cadmium,mercury and inorganic arsenic in different yearsIn 2013?2015 years in Rizhao City,the average value of lead content in fresh seafood sold in markets was 0.114 mg/kg,0.136 mg/kg,0.183 mg/kg;the average value of cadmium content was 0.198 mg/kg,0.220 mg/kg,0.268 mg/kg;the average value of mercury content was 0.048 mg/kg,0.064 mg/kg,0.058 mg/kg;the average value of inorganic arsenic content was 0.115 mg/kg,0.119,mg/kg 0.138 mg/kg.Result of the Krusal-Wallis test is lead(P<0.01),cadmium(P=0.076),mercury(P= 0.581)and inorganic arsenic(P =0.659).3.2 Analysis of the qualified rate of seafood in different yearsThe content of mercury and inorganic arsenic in seafood products detected in three years are all qualified,but content of lead and cadmium have exceeded the standard.The qualified rates of lead content were 100%,99.38%and 99.38%,and the qualified rates of cadmium content were 97.12%,96.56%and 95.33%.The difference of qualified rates of lead and cadmium content in the three year samples was analyzed by chi-square test,and the X2 of lead was 1.300(P>0.05),the X2 of cadmium was 1.285(P>0.05).4.Analysis results of lead,cadmium,mercury and inorganic arsenic in different sampling points4.1 Content comparison of lead,cadmium,mercury and inorganic arsenic in different sampling pointsThe average value of lead content in samples in the seafood market and large supermarket was 0.140 mg/kg and 0.152 mg/kg;the average value of cadmium content was 0.230 mg/kg,0.235 mg/kg;the average value of mercury content was 0.056 mg/kg,0.069 mg/kg;the average value of inorganic arsenic content was 0.120 mg/kg,0.129 mg/kg.The sample contents of lead,cadmium,mercury and inorganic arsenic were not significantly different in seafood markets and large supermarkets by t test(P>0.05).4.2 Analysis of the qualified rate of seafood in different sampling pointsThe contents of mercury and inorganic arsenic in the samples collected from seafood markets and supermarkets are all qualified,while the content of lead and mercury exceeded the standard.The qualified rate of lead content in the sample is 99.53%and 99.52%,and the qualified rate of cadmium content in the sample is 95.81%and 96.67%.The difference of qualified rates of lead and cadmium content in seafood markets and supermarkets samples was analyzed by chi-square test.The X2 of lead is 0.23,(P>0.05),the X2 of cadmium is 0.44(P>0.05).5.Analysis of seafoods safety in the aspects of contents of lead,cadmium,mercury and inorganic arsenic5.1 Comprehensive pollution index evaluation method for heavy metalsThe seafood pollutant index(XMp1)was respectively,the double shell class(0.107)>cephalopod(0.058)>crustacean(0.034)>sea fish(0.027).5.2 Single-factor pollution index evaluation methodSingle pollution index values of lead were:crustacean(0.232)>sea fish(0.168)>the double shell class(0.131)>cephalopod(0.120);cadmium were:the double shell class(0.401)>crustacean(0.228)>cephalopod(0.189)>sea fish(0.180);mercury were:the double shell class(0.148)>cephalopod(0.106)>crustacean(0.094)>sea fish(0.088);inorganic arsenic were:the double shell class(0.151)>cephalopod(0.109)>crustacean(0.092)>sea fish(0.058).[Conclusions]1.There are differences on the content of lead,cadmium,mercury and inorganic arsenic in different types of seafood,and the pass rate is related to the category of its species.The double shells have the lowest pass rate,followed by the crustaceans and sea fish,and the cephalopods is all qualified.2.From 2013 to 2015,content of lead in seafood was different in at least two years,while the content of cadmium,mercury and inorganic arsenic in seafood and the pass rate of lead,cadmium,mercury and inorganic arsenic were not related to the year.3.The content and qualified rate of lead,cadmium,mercury and inorganic arsenic in fresh seafood sold in Rizhao city do not have correlations with sampling points.4.The double shell seafood have the strongest enrichment capability of lead,cadmium,mercury and inorganic arsenic.Lead in the crustaceans is in light pollution level,cadmium in the double shells and crustaceans is in light pollution level,the other seafood are not contaminated and clean.