Investigation On Cadmium Content In Cereals And Dietary Exposure Assessment Of Residents In Chongqing

Background : Cadmium is a kind of metal element which is naturally stable on the surface of the earth ’ s crust,and its content is usually very low.It is mainly used in electroplating,chemical industry and electronic industry.Cadmium is a kind of non-essential element for human body and has no nutritional value.Most of the cadmium in the environment is absorbed by plants,especially crops,and then absorbed by the human body through the food chain.It combines with high molecular organic matter in the human body,resulting in pathological changes in liver,kidney and bone,and even reproductive toxicity to the human body,resulting in infertility or infertility.It has strong teratogenic,carcinogenic and mutagenic effects.The World Health Organization has identified cadmium as one of the food contaminants that have been prioritized for research.Among the hazardous chemical substances of global significance proposed by the United Nations Environment Program in 1984,Cd ranks first.Research in recent years has found that the crops with the highest absorption of cadmium are cereals such as rice,and the news of "cadmium rice" is also frequently reported.At the same time,according to the 2002 and 2010-2012 surveys on the nutritional and health status of Chinese residents,cereals are the main body of Chinese residents’ diet and the main source of energy for urban and rural residents in my country.Therefore,the quality and safety of cereals is an important part of food safety.Studying the current status of cadmium pollution and evaluating their dietary exposure has far-reaching impact and practical significance for protecting the national food safety.Objective:(1)To investigate the consumption of cereals of residents in Chongqing.(2)To investigate the distribution of cadmium pollution in cereals sold in Chongqing.(3)Assessment of dietary cadmium exposure : based on the results of cadmium content in food,combined with the dietary exposure of cadmium in food,the dietary exposure assessment of cadmium in cereal food of Chongqing residents was completed based on point assessment model and probability assessment model.Methods:(1)Chongqing is divided into four districts,namely,the main city,the west,the northeast and the southeast of Chongqing.According to the principle of multi-stage stratified cluster sampling,1-2 districts and counties are selected from each district to carry out the investigation of residents ’food consumption.Residents aged 3 years and above(living for at least 6months or more)in each district and county were selected as subjects.The basic information of families and individuals of the surveyed population was collected by questionnaire survey,and the food consumption status of the respondents was collected by discontinuous 3-day 24 hours dietary recall method.SAS9.4 statistical software was used to analyze the dietary data,and the average intake of the whole population and the consumer population was calculated.SPSS26.0 statistical software was used to analyze the basic information of the family and the related factors of dietary intake.(2)According to the characteristics of population,economy and geographical location in different regions of Chongqing,Chongqing is divided into four districts,namely,the main city,the west,the northeast and the southeast of Chongqing.According to the principle of stratified random sampling,2-3 districts and counties are selected in each district.In the supermarkets,shops and agricultural markets where the daily consumption of local residents is large,local self-produced or marketed cereals are collected according to the national standards.According to GB5009.268-2016,heavy metal content in samples was detected by a laboratory certified by CNAS.Excel 2007 and SPSS26.0 software were used to collate,classify,summarize and calculate the test data.Origin2018 was used to draw the graphics.Shapiro-Wilk normality test was used to verify the data distribution.The pollution degree of the sample was preliminarily evaluated by single factor pollution index.(3)According to the point evaluation formula,the evaluation parameters were adjusted,and the food consumption and pollutant concentration of all the investigated population were calculated in the form of block grouping.According to the probability evaluation formula,based on the @ RISK evaluation software,the model input parameters were adjusted,and the Monte Carlo simulation was used to evaluate the dietary cadmium exposure by cereal intake.Results:(1)Results of grain food consumption survey : In this study,a total of4014 valid dietary data of permanent residents aged 3 and above were collected.The characteristics of the sample population were mainly women,primary school and below education level,and housework.The overall consumption rate of cereal food in the population was high,with an average consumption rate of 95.57 % and an average consumption of 252.39 g / d,which basically reached the recommended value of the dietary guidelines,but there was a significant difference in the intake between the sections.(3)Cadmium contamination of cereals sold on the market : 240 cereal samples were collected in this study,with the detection rate of 98.33 % and the exceeding rate of 3.33 %.The average detection rate of all samples was0.0563 mg / kg.The results of single factor pollution index suggested that most samples in this study belonged to the first-class products,accounting for 88.33 %,which could be evaluated as safety.(3)Dietary exposure assessment of cadmium in cereal food : According to the point assessment and probability assessment results,the average dietary cadmium exposure of cereal food in our city were 7.80μg / kg.b /m and 8.46μg / kg.bw/m,respectively,which were lower than the health guidance value standard proposed by JECFA.By comparing the results of point assessment and probability assessment,the results show that the results of the two assessment methods are roughly the same.In contrast,the results of point assessment are more conservative,and the results of probability assessment model are more robust and more in line with the daily actual situation.Conclusions:(1)The average level of cereal intake of residents in Chongqing basically meets the recommended requirements of dietary guidelines,but the intake of some areas and populations is probably insufficient.(2)The cadmium pollution of cereals sold in Chongqing is at a safe level as a whole.(3)The average dietary cadmium exposure through cereal food intake in Chongqing was lower than the health guidance value standard proposed by JECFA,and there was no health risk for most healthy people.