Assessment of Human Health Risk Based on Characteristics of Heavy Metal Contents in Foods Sold in Beijing,China

Author:Wei Jun Xiao

Supervisor:zuo kuang


Degree Year:2019





"People is the basic of a country,food is what people relies on,and safety is paramount for food." Food safety has always been considered a significant concern for the Chinese government,which is because it relates to the national economy and people’s livelihood.In order to study the concentrations of heavy metals as well as the distribution characteristics for foods on sale across Beijing,the risk assessment of food safety was conducted for the residents living in Beijing.From October 2016 to December 2017,totally 13 types of commercially available food(including Cereals,Legumes,Potatoes and Eggs)were collected from 16 districts in Beijing.The concentrations of Cadmium(Cd),Chromium(Cr),Copper(Cu),Iron(Fe),Manganese(Mn),Lead(Pb)and Zinc(Zn)in the collected samples were determined by using a combination of graphite furnace atomic absorption spectrometry(GF-AAS),flame atomic absorption spectrometry(F-AAS)and inductively coupled plasma optical emission spectrometry(ICP-OES).The concentrations of heavy metals in commercial foods offered in Beijing and its distribution characteristics were studied for the first time.In addition,the Nemero comprehensive pollution index method was applied to making assessment of heavy metal pollutions found in foods.With the principle of heavy metal concentrations in samples taken into account,the principle of dietary consumption was given priority.A combination of correlation analysis,factor analysis and cluster analysis were made using IBM SPSS Statistics 22 for the selected samples including rice,leeks,apples and mung beans.Meanwhile,combined with the dietary data of The Fifth China Total Dietary Study(TFCTDS),the dietary exposure and safety risk assessment were conducted of the heavy metals as contained in the foods offered on the market in Beijing.The main conclusions drawn from this study are as follows:(1)Except for the over-standard samples,the heavy metal concentrations of the simplyprocessed samples were found to be lower than that of the highly-processed samples,and the heavy metal concentrations in the high moisture samples including vegetables,fruits,beverages,alcohol,milk and the likes were significantly lower than in grains,beans,nuts and condiments.Among the 79 types of samples,chocolate,dried chili and cumin were found to be at the alarming levels,with fish being at the medium level.For the remaining samples,it was at the levels considered as safe.The average index of comprehensive pollution for the commercially available samples in Beijing was 0.118,indicating that the current levels of heavy metal pollutions in foods on sale in Beijing was acceptable and safe.(2)From the perspective of environmental geochemistry,the environmental impact made by heavy metals in the primary agricultural products was analyzed with rice being exemplified.By comparing the relationship among elements in the crust,soil,rice and human blood,the dynamic balance between human and nature was identified.(3)The average daily intake of Cd,Cr,Cu,Fe,Mn,Pb and Zn among residents living in Beijing was about 12.26 μg/d,153.17 μg/d,1.90 mg/d,20.19 mg/d,7.12 mg/d,25.16 μg/d and 12.69 mg/d,respectively.Besides,cereals and legumes were the main sources of the Cd,Cu,Fe,Mn,Pb and Zn.(4)The target hazard quotient(THQ)of Cd,Cr,Cu,Fe,Mn,Pb and Zn was 0.18,0.76,0.77,0.43,0.76,0.10 and 0.63,respectively.The total target hazard quotient(TTHQ)= 3.64 < 10.The target cancer risk(TCR)of Pb was 3.23×10-6,which was within the acceptable range.Therefore,based on the current dietary structure,the THQ and TCR of heavy metals in foods sold in Beijing were considered as acceptable and safe.Long-term consumption of these foods would not have detrimental effect on the health of residents living in Beijing.