Chinese Total Diet Study Research Articles

Simultaneous determination of 19 triazine pesticides and degradation products in processed cereal samples from Chinese total diet study by isotope dilution–high performance liquid chromatography–linear ion trap mass spectrometry

A selective and sensitive isotope dilution–high performance liquid chromatography–linear ion trap mass spectrometry (Isotope Dilution–HPLC–LIT-MS3) method was developed for the simultaneous determination of 19 triazine pesticides and their degradation products in processed cereal samples from Chinese total diet study (TDS). The method integrated the addition of isotope internal standards, liquid–liquid extraction (LLE), clean-up with MCX solid-phase extraction (SPE) cartridges and HPLC–LIT-MS3 analysis with selected reaction monitoring (SRM) mode. Matrix-matched calibration curves showed good linearity (R2≥0.9940) verified by applying the Mandel's fitting test (p>0.087) performed at the 95% confidence level. Decision limits (CCαs) and detection capabilities (CCβs) of the 19 triazine pesticides and their degradation products fell in the ranges of 0.0020–0.4200μgkg−1 and 0.0024–0.4500μgkg−1, respectively. Recoveries ranged from 70.1% to 112.8%, with the relative standard deviations (RSDs) ranging from 1.5% to 13.5%. Furthermore, the proposed method was applied to analyzing the proposed cereal samples from the fourth Chinese TDS. Eleven triazines were detected in six cereal samples with the concentrations ranging from 0.013 to 0.987μg kg−1. This method can also be used for the further determination of the triazines in other food group composites, and ultimately served as a methodological foundation for assessing the triazines in the average Chinese diet in the general population.

Dietary intake of PCDD/Fs and dioxin-like PCBs from the Chinese total diet study in 2007

Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in 96 food composite samples from eight varieties of food groups from the Chinese total diet study (TDS) in 2007. The concentrations of samples, expressed as WHO toxic equivalents (TEQ), ranged from 0.001pg TEQ g−1 to 0.85pgTEQg−1 (fresh weight). Dietary intake of PCDD/Fs and dl-PCBs of 12age/gender subgroups of the Chinese population subsequently estimated ranges from 15.4pg TEQkg−1bwmonth−1 to 38.7pgTEQkg−1bwmonth−1 for average population and from 68.5pgTEQkg−1bwmonth−1 to 226.1pgTEQkg−1bwmonth−1 for high consumers (the 97.5th percentile). Dietary exposure of children (mean: 32.5pgTEQkg−1bwmonth−1) is significantly higher than that of the adults (mean: 21.5pgTEQkg−1bwmonth−1) (p<0.01) presumably due to more food consumed by children relative to their body weight compared to adults. There is no difference of dietary exposure, expressed as pg TEQkg−1bw, found between different genders. Across various regions in China, there are large differences of dietary exposure of adult population and pattern of contribution of food groups to total exposure due to different contamination level and food habits. Dietary exposures of average population of various subgroups were all below the PTMI recommended by JECFA, but those of higher consumers were found exceeding or comparable to the PTMI.

Dietary exposure to persistent organochlorine pesticides in 2007 Chinese total diet study

Dietary exposure to persistent organochlorine pesticides (OCPs) was assessed for Chinese populations, using the total diet study (TDS) approach in 2007. Multistage random cluster sampling method was used in this study. 108 composite samples, representative of foods “as consumed” by the Chinese were analyzed for residues of OCPs by a multi-residue method. The result showed that hexachlorobenzene (HCB), dichloro-diphenyl-trichloroethane (DDT), chlordane compounds (CHLs), hexachlorocyclohexane (HCH) and heptachlor could be detected in, respectively 84%, 39%, 37%, 13% and 5% of all samples. Concentrations of DDT in all samples ranged from undetectable levels to 72.2μg/kg. Others were minor components in the OCPs profile. The residual levels of OCPs were significantly below the Extraneous Maximum Residue Limits (EMRLs). Based on the 2000 nationwide food consumption survey, the average dietary exposure of the Chinese to DDT, HCH, HCB, CHLs, and heptachlor was estimated to be 0.016, 0.002, 0.009, 0.006, and 0.001μg/kg body weight per day respectively, showing a significant decrease trend compared with the past. The major food groups contributing to dietary OCPs were aquatic foods, meats, and cereals. The average and high end estimated daily intakes of different OCPs for the Chinese were both lower than the tolerable daily intake (TDI) suggested by authorities indicating low health risk of OCPs dietary exposure among Chinese adults at present. However, the risk of carcinogenicity of the OCPs should be concerned with if the carcinogenicity effects from the exposures to these OCPs were considered.

Perfluorinated compounds in seafood from coastal areas in China

Diet is an important source of perfluorinated compound (PFC) exposure and seafood is an important diet component for coastal populations. Therefore, it is necessary to monitor the concentrations of PFCs in seafood. In this study, we measured thirteen PFCs in 47 fatty fish and 45 shellfish samples collected from six coastal provinces in China (Liaoning, Shandong, Jiangsu, Zhejiang, Fujian, and Guangdong), using an ultra-performance liquid chromatography and tandem mass spectrometry (UPLC–MS/MS). Perfluorooctanesulfonate (PFOS) was the dominant PFC in fatty fish which accounted for 38% of total PFCs, whereas perfluoroctanoic acid (PFOA) was the predominant PFC in shellfish. Concentrations of PFOS were ranged from less than 1.4 to 1627pg/g wet weight in fatty fish, with the highest concentration in red drum from Jiangsu. Concentrations of PFOA in shellfish ranged from less than 5.4 to 7543pg/g wet weight, with the maximum concentration found in briny clam also from Jiangsu. Compared with other studies, the PFC levels in seafood collected from our studied areas are relatively low. The estimated dietary intakes (EDI, pg/kg body weight /day) of PFOA, PFOS and total PFCs for the reference man (63kg body weight) were calculated by multiplying the mean concentrations (pg/g wet weight) of PFOA, PFOS and total PFCs in six coastal provinces with the daily consumption data (g/day) from the fourth Chinese total diet study carried out in 2007. The highest EDI of PFOS and PFOA were found to be 694pg/kg body weight/day and 914pg/kg body weight/day in Guangdong and Jiangsu, respectively. However, the highest EDI of total PFCs was found in Fujian at 2513pg/kg body weight/day. The EDI from seafood is much lower than the tolerable daily intake (TDI) recommended by the European Food Safety Authority in 2008 indicating low health risk of PFC exposure via eating seafood among the coastal populations in China.

The development and evolution of Chinese Total Diet Study

The development and evolution of Chinese Total Diet Study

Estimation of methylmercury intake from the 2007 Chinese Total Diet Study

Methylmercury intake for adult males of twelve provinces in China was estimated by means of the 2007 Chinese Total Diet Study. Methylmercury levels were measured in twelve food groups of each province of four regions and was only found in the aquatic food groups. The range for methylmercury contents of aquatic foods was 3.29–31.60 µg kg−1, being 50–87% of total mercury. Methylmercury intakes from aquatic foods for adult males of twelve provinces ranged from 0.003 to 0.138 µg kg−1 bw week−1 with average of 0.041 µg kg−1 bw week−1, which were estimated according to methylmercury contents and corresponding aquatic food consumption. Methylmercury intakes for the Chinese population were far below the corresponding provisional tolerable weekly intake (PTWI), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Consequently, there was little health risk from methylmercury exposure for the average Chinese population.

Dietary Exposure Assessment of Chinese Adults and Nursing Infants to Tetrabromobisphenol-A and Hexabromocyclododecanes: Occurrence Measurements in Foods and Human Milk

Tetrabromobisphenol A(TBBPA) and hexabromocyclododecane diastereoisomers (alpha, beta, and gamma-HBCD) were determined in 24 pooled human milk samples and 48 Chinese total diet study (TDS) samples collected in 2007. On the basis of ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) analysis, levels of TBBPA ranged from < LOD to 5124 pg/g lipid weight (lw) in human milk and from < LOD to 2044 pg/g lw in TDS samples. The alpha-HBCD diastereoisomer, which ranged from < LOD to 2776 pg/g lw in human milk and from < LOD to 2224 pg/g lw in TDS samples, was generally the most abundant isomer comparing with beta- and gamma-HBCD. The average estimated daily intake (EDI) of TBBPA via human milk for nursing infants with a range 320-37240 pg/kg bodyweight (bw)/day was 5094 pg/kg bw/day, while that of sigmaHBCD was 5837 pg/kg bw/day with a range 670-17320 pg/kg bw/day. The medium bound (< LOD = 1/2LOD) EDI(TBBPA) for a "reference" man via animal origin foods was 256 pg/kg bw/day and EDI(sigmaHBCD) was 432 pg/kg bw/day. Meat and meat products were the main source in the total dietary intake of TBBPA and sigmaHBCD. Our research on the estimated daily intake of TBBPA and sigmaHBCD by the Chinese population indicated large variations in TBBPA and sigmaHBCD levels between provinces. Overall, our data indicate the Chinese EDI was lowerthan the EDI from similar studies in Europe.

Study on the contamination level and intake of organotins of Chinese dietary

To obtain the baseline data of organotins' pollution of Chinese meal in order to carry on primary danger analysis of the exposure. The samples of the third Chinese total diet study were determined by gas-chromatography pulsed flame photometric detector to estimate dietary intake of organotins. The dietary intake of organotins was estimated according to the contamination level of organotins and food consumption. Only several kinds of organotin were founded in several foods and no organotins was found in fruit, sugar and alcoholic beverages. Dimethyltin (DMT) were detected in some samples from Southern 1 area, the content ranged from 1.5 microg/kg to 4.1 microg/kg. Butyltin compounds existed in seafoods from Southern 1 area, the contents of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MTB) being 0.9 microg/kg, 1.1 microg/kg, 1.4 microg/kg respectively. The lower limit and upper limit of exposure to tributyltin were from 0.003 microg x kg(-1) x d(-1) to 0.006 microg x kg(-1) x d(-1) and from 0.004 microg x kg(-1) x d(-1) to 0.019 microg x kg(-1) x d(-1) respectively. Comparing to ADI of tributyltin (WHO), the Chinese dietary intake of tributyltin only accounted for 2.5% and that of butyltin only accounted for 3.5%. To identify the contamination source of organotins in Southern 1 area, the individual samples of aquatic food from individual province were analyzed, revealing that Fujian province and Shanghai City were the main contributors of organotins pollution in this area. The belt fish and yellow croaker were typical pollution samples. Higher levels of DMT were detected in seafood samples from Shanghai. The exposure level of Chinese dietary was relative low, however the sources of organotin pollution needs further investigation.

Dietary intake of polychlorinated dioxins, furans and dioxin-like polychlorinated biphenyls from foods of animal origin in China

Four food groups of animal origin from the Chinese Total Diet Study (TDS) in 2000 were analysed for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (PCBs). The samples were from four regions, covering 12 provinces of China. PCDD/Fs, expressed as WHO toxic equivalents (TEQ), ranged from 0.02 to 0.28 pg TEQ g−1 and dioxin-like PCBs ranged from 0.01 to 0.24 pg TEQ g−1 (wet weight, ND = LOD), in all samples. Using food consumption data from a 3-day household dietary survey, daily dietary intake of dioxin-like compounds from foods of animal origin in China was estimated. Daily intake among regions ranged 0.09–0.59 pg TEQ kg−1 body eight day−1.

The Chinese Total Diet Study in 1990. Part II. Nutrients

This paper reports the intakes of 72 nutrients and their dietary sources obtained from the Chinese total diet study in 1990. Most of the nutrient intakes are close or equal to their corresponding recommended daily allowances (RDAs). Both the total energy intake (2203 kcal) and the proportions contributed by protein, fat, and carbohydrate meet the current Chinese RDAs and the World Health Organization (WHO) nutrient goals. The average protein intake was 64 g/day. The intake of essential amino acids all exceeded the Chinese RDA, and their proportions were generally consistent with the WHO recommended pattern. The average fat intake was 51.2 g/day (21.2% of the total energy intake). However, the dietary fat intake has been increasing significantly in the Chinese diet and the proportion of animal fat has reached 53% of the total fat intake. The total saturated:total monounsaturated: total polyunsaturated fatty acid ratio was 1.0:1.5:1.0. Although the average cholesterol intake was only 179 mg/day, it was 248 mg/day in the South 1 region. The intakes of thiamine and riboflavin were below the RDA. Retinol intakes in all the 4 regions were low. Most (80%) of the retinol (equivalent) intakes were from carotenoids. The average intake of total tocopherol was 89% of the RDA, and among the 4 regions, only the South 2 region has relatively low intake. The intakes of iron, copper, manganese, sodium, and phosphorus were adequate. The intakes of calcium, zinc, and potassium were insufficient, and intakes of selenium and magnesium were a little low. High sodium and low potassium intake is a traditional problem in the Chinese diet.

The Chinese Total Diet Study in 1990. Part I. Chemical Contaminants

The Chinese total diet study in 1990 estimated the dietary intake of 24 chemical contaminants and 72 nutrients from 4 market baskets collected and prepared in 12 provinces. Twelve food group composites were made for each regional market basket. The overall dietary Pb, Cd, Hg, hexachlorocyclohexane HCH, and DDT intakes were well below their corresponding acceptable daily intakes. However, the Pb content of eggs from the 2 southern regions exceeded the tolerance limit. The Hg content of legumes just reached the tolerance limit, and Hg in eggs from the North 1 region exceeded the tolerance limit. The dietary HCH intake has decreased significantly since the 1980s, but dietary DDT intake has decreased rather slowly. Five organophosphorus pesticides were detected out of a total of 12 organophosphorus pesticides analyzed. Among them, methamidophos was the most outstanding. The intake of total committed dose equivalents (CDEs) of the 6 radionuclides was 0.24 mSv/a; only 1.5% was accounted for by 90Sr and 137Cs. 210Pb, 210Po, 226Ra, and 228Ra accounted for 98.5% of the total CDEs. The main food sources of those radionuclides were cereals, vegetables, and aquatic foods. Aflatoxin B1 was detected at very low levels only in the cereal composite of the North 1 region. Aflatoxin M1 was not detected in any of the milk and milk products. The overall results show that there is no significant environmental contamination of the average Chinese diet.

Effect of dislocations on the lattice thermal conductivity of superconducting niobium: A.C. Anderson and S.C. Smith, Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801

A selective and sensitive isotope dilution–high performance liquid chromatography–linear ion trap mass spectrometry (Isotope Dilution–HPLC–LIT-MS3) method was developed for the simultaneous determination of 19 triazine pesticides and their degradation products in processed cereal samples from Chinese total diet study (TDS). The method integrated the addition of isotope internal standards, liquid–liquid extraction (LLE), clean-up with MCX solid-phase extraction (SPE) cartridges and HPLC–LIT-MS3 analysis with selected reaction monitoring (SRM) mode. Matrix-matched calibration curves showed good linearity (R2 ≥ 0.9940) verified by applying the Mandel's fitting test (p > 0.087) performed at the 95% confidence level. Decision limits (CCαs) and detection capabilities (CCβs) of the 19 triazine pesticides and their degradation products fell in the ranges of 0.0020–0.4200 μg kg−1 and 0.0024–0.4500 μg kg−1, respectively. Recoveries ranged from 70.1% to 112.8%, with the relative standard deviations (RSDs) ranging from 1.5% to 13.5%. Furthermore, the proposed method was applied to analyzing the proposed cereal samples from the fourth Chinese TDS. Eleven triazines were detected in six cereal samples with the concentrations ranging from 0.013 to 0.987 μg kg−1. This method can also be used for the further determination of the triazines in other food group composites, and ultimately served as a methodological foundation for assessing the triazines in the average Chinese diet in the general population.