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Daily intake of total and inorganic arsenic, lead, and aluminum of the Japanese: Duplicate diet study
Journal of Food Composition and Analysis 77 (2019) 77–83
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Daily intake of total and inorganic arsenic, lead, and aluminum of the Japanese: Duplicate diet study☆ Akiko Hayashia,1, Fumio Satoa,2, Tomoko Imaia,3, Jun Yoshinagab, a b
T
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Food Safety Commission, 5-2-20 Akasaka, Minato, Tokyo, 107-6122, Japan Faculty of Life Sciences, Toyo University. 1-1-1 Izumino, Itakura, Oura, Gunma, 394-0193, Japan
A R T I C LE I N FO
A B S T R A C T
Keywords: Duplicate diet Total arsenic Inorganic arsenic Lead Aluminum
Daily intakes of total (TAs) and inorganic arsenic (iAs), lead (Pb) and aluminum (Al) of the Japanese were estimated by the analysis of duplicated diet samples. The samples were collected for 3 consecutive days from 319 subjects (total number: 949) living in Japan during 2006–2010 by the Ministry of the Environment of Japan. TAs, Pb and Al concentrations in duplicated diet samples, determined by ICP mass spectrometry (ICP-MS) preceded by a microwave acid digestion, and iAs was by liquid chromatography-ICP-MS preceded by an acidic extraction, were used for this study. Median 3-days average intake was calculated to be 2.31, 0.260, 0.0928, and 41.1 μg/kg/day, for TAs, iAs, Pb and Al, respectively (138, 15.3, 5.40, and 2363 μg/person/day). The daily intake levels were found to vary according to subjects’ gender (TAs, Pb, and Al), but this was explained by variation in the amount of daily food consumption. Daily TAs intake was found to vary with age grade, districts where community is located and types (urban/farming/fishing) of community, probably reflecting fish/seaweed consumption.
1. Introduction Metals and metalloids are ubiquitous in the environment with both natural and anthropogenic origins. They are present in food to be the major source for human exposure. Since the exposure to some of the metals and metalloids are known to be closely related to human health and diseases, dietary intake levels of such metals and metalloids have been a matter of concern in the field of environmental science, nutritional science, food safety and others. In this publication, daily dietary intake levels of total arsenic (TAs), inorganic arsenic (iAs), lead (Pb) and aluminum (Al) of the general Japanese people are presented. These metals and metalloids were selected because they have been attracting interest in the risk assessment bodies: Provisional Tolerable Weekly Intakes (PTWIs) for Pb and As, once set by JECFA in the past, were withdrawn in 2010, because the PTWIs were found not suitable for preventing health effects (JECFA, 2011a,b). On the other hand, in 2011, JECFA has set a renewed PTWI for Al to be 2 mg/kg/week (formerly 1 mg/kg/week) based on the re-
assessment of Al health risk (JECFA, 2011c). In response to the evaluations of JECFA on the risks of these metals and metalloids, other bodies started assessment/reassessment of the risks. Food Safety Commission of Japan (FSCJ) is one of such bodies and has recently assessed health risk of As in food. Risks of Pb and Al are currently under assessment. During the assessment of FSCJ, it has been recognized that reliable data on daily intake of As, Pb, and Al of the Japanese are not abundant. It was particularly so for iAs and Pb: iAs intake data are limited not only in Japan but also worldwide, probably due to analytical difficulty, though that on TAs was relatively abundant (e.g., Falcó et al., 2006; National Institute of Health Sciences (NIHS), 2008; Liu et al., 2010; Domingo et al., 2012; Luo et al., 2018). Daily intake of Pb of the Japanese have been reported, however, variation among the reports were large possibly reflecting downward changes of Pb levels in foods with time (National Institute of Health Sciences (NIHS), 2008), which might be also accompanied with technical problems in the analysis of Pb and calculation of daily intake (e.g., inclusion/exclusion of non-detectable
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The views expressed in this paper do not necessarily represent positions or policy of Food Safety Commission of Japan. Corresponding author. E-mail address: [email protected] (J. Yoshinaga). 1 Present address at Japan Agency for Medical Research and Development. Muromachi Chibagin Mitsui Bldg, 1-5-5 Nihonbashi-Muromachi, Chuo, Tokyo 1030022, Japan. 2 Present address at Fisheries Agency Niigata Fisheries Coordination Office. 1-5-15 Yachiyo, Chuo-ku, Niigata, Niigata 950-0909, Japan. 3 Present address at Tokyo Quarantine Station. Tokyo Kowan Godochosha, 2-7-11 Aomi, Koto, Tokyo 135-8615, Japan. ⁎
https://doi.org/10.1016/j.jfca.2019.01.009 Received 19 December 2017; Received in revised form 26 December 2018; Accepted 18 January 2019 Available online 22 January 2019 0889-1575/ © 2019 Elsevier Inc. All rights reserved.
Journal of Food Composition and Analysis 77 (2019) 77–83
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HNO3 (Kanto Chemicals Co. Ltd., Tokyo, Japan) and H2O2 (Atomic Absorption Grade, Kanto Chemicals) in microwave digestion systems (ETHOS TC or Ultra Wave, Milestone General Co. Ltd., Yokohama, Japan). After digestion, acetic acid (Reagent Grade, Kanto Chemicals) was added for the compensation of carbon interference on As and made up to 50 g with MQ water. TAs, Pb and Al concentrations in the digested samples were determined by ICP mass spectrometry (ICP-MS) (Agilent 7500ce and 8800, Agilent Technologies, Tokyo, Japan). ICP-MS was operated under helium collision mode and by using gallium (for Al), tellurium (for TAs), and thallium (for Pb) as internal standards. For the analysis of iAs, 2 g of sample was extracted with 10 mL of 0.3 mol/L HNO3 in a test tube at 100 °C for 2 h according to Nishimura et al. (2010) with a modification. After centrifugation, the supernatant was recovered and then the residue was washed with 5 mL of MQ, which was recovered and combined with the dilute HNO3 supernatant. The pH of the combined supernatant was adjusted to 3 with NH4OH, and then the volume was made up to 20 mL. The solution was filtered through 0.45 μm cellulose membrane filter and 20 μL of it was injected into a liquid chromatography-ICP-MS (LC-ICP-MS) system for As speciation analysis. The separation of As compounds by the LC (Agilent 1200 Series, Agilent Technologies, Co. Ltd.) was based on ion-pair reversed phase mode (Narukawa et al., 2010) using CAPCELL PAK C18 MG (4.6 mm I.D. × 250 mm) (Shiseido Co. Ltd. Tokyo, Japan). As(V), As(III), methylarsonic acid, dimethylarsinic acid, arsenobetaine, trimethylarsine oxide, and tetramethylarsonium ion were separated and determined. Since valence of iAs (As(V) and As(III)) could change during the acid extraction, the sum of As(III) and As(V) concentrations was taken as iAs in this study. The analytical results of the duplicate diet samples were compiled in a report (Japan Food Research Laboratories, 2014).
samples). As a result, reliable recent data on daily Pb intake is limited. In this study, a particular care was paid to analytical quality assurance so that reliable daily intake information is available for risk assessors. Although daily intake levels of metals/metalloids in a population are domestic/local issue, it is indispensable in the risk assessment of the metal in that particular country/area, which will be referenced in the assessment in other countries. 2. Materials and methods 2.1. Duplicate diet samples Duplicate diet samples analyzed in this study were obtained from the participants in the monitoring programs “Survey of the Exposure to Dioxins and Other Chemical Compounds in Humans” (2006–2010) conducted by the Ministry of the Environment of Japan (Ministry of the Environment of Japan, 2012). In the survey, one prefecture was selected from each of 5 districts of Japan (Hokkaido/Tohoku, Kanto/ Koshin-etsu, Tokai/Hokuriku/Kinki, Chugoku/Shikoku, Kyushu/Okinawa in the order of north to south of Japan Archipelago), and 3 different types of community, i.e., urban, farming, and fishery community, were selected from each of the Prefecture in each year during 20062008. During 2009–2010, urban and fishery communities were selected from each Prefecture. Fifteen to twenty participants were recruited for the Survey from each community each year whose blood samples were measured for organic contaminants. Among the participants, 5 in each community supplied duplicate diet samples for 3 consecutive days each year. In total, 325 participants of the survey supplied duplicate diet samples. Total weight of one day duplicate diet was recorded. The duplicate diet samples were individually homogenized in a food processor and stored in freezer. An aliquot of the frozen sample was subject to TAs, iAs, Pb, and Al analyses. Leaching test did not detect As, Pb and Al from the processer. For this study duplicate diet samples from 319 participants were available: 6 samples were missing for various reasons.
2.4. Analytical quality control Analytical quality was verified both internally and externally. Blanks and in-house control material with food matrix was run in each batch of measurements. Linearity of calibration curves were checked at every measurement. Lower limit of detection of TAs, iAs, Pb and Al as expressed in the concentrations in duplicate diet sample were 0.00008, 0.0013, 0.0003 and 0.03 μg/g, respectively, which roughly corresponded to 0.2, 3, 0.7 and 75 μg as daily intake/person, respectively. Accuracy of the analyses was confirmed by the analysis of certified reference materials, i.e., NIST SRM 1548a Typical Diet, NIST SRM 1568a Rice Flour, IRMM 804 Rice Flour, and NMIJ CRM 7503 Rice Flour for TAs, Pb and Al, and NMIJ CRM 7503-a White Rice Flour and NMIJ CRM 7405-a Hijiki for iAs. As presented in Table 1, the measured values were in accordance with the certified values of the CRMs with small standard deviations indicating that the trueness and precision of
2.2. Subject’s information Gender, age grade (10-yrs interval), and body weight of the subject, who supplied 3-days duplicate diet samples, was obtained for this study from the questionnaire data of the survey. 2.3. Analytical methods Analysis of TAs, iAs, Pb and Al was carried out at a commercial laboratory, Japan Food Research Laboratories (Tokyo, Japan). Two grams of thawed duplicate diet sample was digested with Ultrapure Table 1 Analytical Results (unit: mg/kg) of Certified Reference Materials$.
NIST SRM 1548a NIST SRM 1598a IRMM 804 NMIJ CRM 7503 NMIJ CRM 7503-a NMIJ CRM 7405-a
Measured Certified Measured Certified Measured Certified Measured Certified Measured Certified* Measured Certified#
TAs
Pb
Al
0.198 ± 0.001 0.2 ± 0.01 0.262 ± 0.007 0.29 ± 0.03 0.0502 ± 0.002 0.049 ± 0.005 0.0986 ± 0.0001 0.098 ± 0.007
0.049 ± 0.002 0.044 ± 0.009
72.3 ± 0.3 72.4 ± 1.52 4.54 ± 0.11 4.4 ± 1.0
iAs
0.414 ± 0.012 0.42 ± 0.07
0.0870 ± 0.0003 0.0841 ± 0.0068 10.2 ± 0.2 10.1 ± 0.5
$
Mean ± SD of 3 replicate analyses are shown. * Sum of the certified values for As(III) (0.0711 ± 0.0029 mg/kg) and As(V) (0.0130 ± 0.0009 mg/kg) with combined uncertainty is shown. # Certified value is based on iAs extracted in water. 78
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our analyses were satisfactory.
Table 2 Characteristics of the subjects who donated duplicate diet samples (n = 319).
2.5. Data analysis
Attribute Gender Male Female Age grade < 20 20–30 30–40 40–50 50–60 60–70 ≥70 District of the community where subjects reside* Hokkaido/Tohoku Kanto/Koushin-etsu Tokai/Hokuriku/Kinki Chugoku/Shikoku Kyushu/Okinawa Type of the community Urban Farming Fishery
TAs, iAs, Pb and Al concentrations in 949 duplicate diet samples from 319 subjects (one missing sample for each of 8 subjects was present) were obtained from ICP-MS and LC-ICP-MS analyses and they were analyzed in this study as follows. The concentration (μg/g) was multiplied by the total amount of the diet sample (g/day) to produce daily intake of the element. In this study, daily intake of the element is basically expressed as μg/kg body weight/day by dividing daily intake by the body weight of the subject. Further, mean of the 3 days intake (mean of two for the 8 subjects with missing data) was taken as the subject’s average intake: thus 319 3-days (or 2-days) average daily intakes for each of TAs, iAs, Pb, and Al are available and used in this study. The standard deviation of the 3-days intakes for each subject was divided by the corresponding 3-days average value to produce coefficient of variation (CV, %) for each of the subjects, which were regarded as intra-individual (between-day) variation. Note that standard deviation and CV for 8 subjects who had 2-days intake data was not calculated. Thus, intra-individual variation CV was obtained for 311 subjects. In contrast, the standard deviation of 319 3-days average values divided by the mean of the 3-days average was regarded as inter-individual variation CV (%). The two CV values were compared. The daily intakes of metals/metalloids distributed log-normally: logtransformed value was used for statistical analysis to compare daily intake between gender (t-test) and those to compare among age grades, 5 districts of Japan where the community is located, and 3 types of the community (one-way analysis of variance, ANOVA). Subjects’ attributes are shown in Table 1. Since the number of < 20 yrs and > 70 yrs subjects was 3 and 1, respectively (Table 1), the < 20 yrs subjects were included in 20–30 yrs age grade and the > 70 yrs subject was in 60–70 age grade, respectively, for age-grade based analysis. SPSS ver. 19 J (IBM Co. Ltd., Tokyo, Japan) was used for statistical analyses.
Body weight (kg) Male Female Weight of one-day duplicate diet sample (g) Male Female
Number
(%)
94 225
(29.5) (70.5)
3 25 59 63 97 71 1
(0.9) (7.8) (18.5) (19.7) (30.4) (22.3) (0.3)
54 73 74 64 54
(16.9) (22.9) (23.2) (20.1) (16.9)
124 95 100 Mean 59.7 68.7 56.0 2493 2647 2429
(38.9) (29.8) (31.3) ± SD ± 11.0 ± 9.7 ± 9.3 ± 646 ± 679 ± 552
* In the order of northern to southern part of Japan Archipelago.
2008). The present result (median 138 μg/person/day) is in agreement with these values. Tsuda et al. (1995) reported higher TAs daily intake (210–260 μg/person/day) based on duplicate diet study. In other countries, generally lower daily intakes have been reported. Higher daily TAs intakes in Japan and some European countries, such as Spain (Llobet et al., 2003; Domingo et al., 2012), are due to greater consumption of fish and seaweeds, which contains high levels of As.
3. Results and discussion 3.1. Subjects
3.2.2. iAs Three duplicate diet studies reported arithmetic mean iAs intake levels of 6.5–33.7 μg/person/day for Japanese populations with a limited number of subjects (Mohri et al., 1990; Yamauchi et al., 1992; Oguri et al., 2012) and one market basket study reported 21 μg/person/ day on bioaccessible fraction basis or 24 μg/person/day on total iAs basis (Oguri et al., 2014). The present result (median 15.3 μg/person/ day) was in accordance with these reported values. These levels were below PTWI for As (15 μg/kg/week or 129 μg/person of 60 kg body weight/day) which was withdrawn in 2010 because it was no longer health protective (JECFA, 2011b). Lower daily iAs intake levels were found in other countries: 2.1–5.6 μg/person/day in Italy (Cubadda et al., 2016) and 1.4–7 μg/ person/day in the UK (Rose et al., 2010) were reported with total diet study design while similar value (13.4 μg/person/day) to the present study was reported in Hong Kong (Wong et al., 2013). Consumption of rice as staple food would be the contributing factor of higher daily iAs intake in Asian countries including Japan.
Table 2 shows demographic characteristics of the 319 subjects. There were 94 male and 225 female subjects. All of them were adult (> 20 yrs old) except for 3 subjects. The subjects were selected from 5 districts of Japan fairly evenly, and so did from 3 different types of community. 3.2. Daily intake levels of TAs, iAs, Pb and Al of the Japanese Table 3 shows distribution of daily intakes of TAs, iAs, Pb and Al (3days average) of the 319 subjects. Minimum, maximum, and 5–95 percentile values, as well as geometric mean values, are presented. Daily intakes per person are also presented for the comparison with published data. There were 8 undetectable samples only for iAs: lower limit of detection could be converted to intake level of 3 μg/person/day or 0.05 μg/kg/day. For the undetectable samples, 1/2 of the converted lower limit of detection intake was substituted for the calculation of the mean value. The daily intakes obtained in the present study were generally in agreement with the recently published intakes of the Japanese subjects but some differences are also found when compared with intake levels reported in other countries.
3.2.3. Pb Higher daily Pb intake (up to 100 μg/person/day) was reported in earlier market basket studies carried out in Japan in 1970s (National Institute of Health Sciences (NIHS), 2008). This was certainly due to more severe environmental contamination with Pb in those days of Japan. Daily Pb intakes thus expected to be variable depending on the time of survey. Most recent market basket survey by the Tokyo Metropolitan Government (2017) and that by Yoshinaga et al. (2017) reported 0.082 μg/kg/day and 4.69 μg/person/day, respectively, which
3.2.1. TAs National Institute of Health Science of Japan (NIHS) has been compiling data from market basket surveys carried out in Japan: during 2000–2007, yearly average daily intakes of TAs were recorded as 145–186 μg/person/day (National Institute of Health Sciences (NIHS), 79
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Table 3 Distribution of daily intakes of TAs, iAs, Pb and Al of the Japanese* (n = 319). Min
Intake per person (μg/person/day) TAs 11.0 iAs <3 Pb 0.73 Al (mg) 0.32
Percentile
Max
Geometric Mean
Geometric SD
5
25
50
75
95
37.9 6.87 2.17 0.84
85.3 10.8 3.90 1.64
138 15.3 5.40 2.36
226 22.0 7.87 4.27
437 45.2 17.3 11.1
1366 99.4 64.8 61.1
136 15.9 5.61 2.67
2.15 1.78 1.84 2.16
1.42 0.185 0.0634 27.1
2.31 0.260 0.0928 41.1
3.89 0.382 0.135 74.8
8.08 0.833 0.319 179
22.8 1.50 1.22 985
2.31 0.270 0.0955 45.4
2.19 1.78 1.88 2.21
Intake per body weight (μg/kg/day) TAs 0.20 0.60 iAs < 0.05 0.110 Pb 0.0120 0.0390 Al 5.7 14.7
* Distribution of the 3-days average intake.
are in good agreement with the present result (median 0.0928 μg/kg/ day or 5.40 μg/person/day). These levels are well below the withdrawn PTWI for Pb (25 μg/kg/week or 214 μg/person of 60 kg body weight/ day). Similar daily intakes to that in this study have been reported in other countries in the last five years: A French total diet study reported mean daily Pb intake of adult and children to be 0.2 and 0.27 μg/kg/ day (Arnich et al., 2012) and Australian market basket study found 0.10.2 μg/kg/day for children (Callan et al., 2014). The US National Health and Nutrition Examination Survey found 0.087-0.107 μg/kg/day for different ethnic populations in the US (Awata et al., 2017). Much higher intake levels were reported in China (2.01 μg/kg/day; Luo et al., 2017), Iran (671 μg/person/day; Rahmdel et al., 2015), and Serbia (72.3 μg/ person/day; Škrbić et al., 2013). In this respect, daily intake level of the Japanese is thought to be among the lowest in the world.
Table 4 Inter- and intra-individual variation.
3.2.4. Al A recent market basket study in Japan reported Al intake from processed and unprocessed foods of 7 categories (Sato et al., 2014). The sum of the intakes from all of the categories showed Al intake of 2.53 mg/person/day for adult (> 20 yrs old) and 2.85 mg/person/day for youth (15–19 yrs old). Lower intake was calculated for young children (7–14 yrs old, 1.98 mg/person/day) and children (1–6 yrs old, 2.35 mg/kg/day). This result for adult is in good agreement with the present result (median 2.36 mg/person/day). A Belgian study estimated adult daily intake of Al to be 0.030 mg/ kg/day which was based on a statistical model of food consumption and measured Al concentrations in pooled foods (Fekete et al., 2013) and this was in agreement with the present result (41.1 μg/kg/day or 0.041 mg/kg/day). Somewhat higher daily intakes of Chinese adult (0.462–1.065 mg/kg/week or 0.066-0.152 mg/kg/day; Yang et al., 2014) and Hong Kong adult (0.60 mg/kg/week or 0.086 mg/kg/day; Wong et al., 2010) were reported. The daily Al intake levels reported in these publications including ours were below the PTWI set by JECFA in 2011 (2 mg/kg/week or 0.286 mg/kg/day).
varied according more to personal preferences in food consumption than to intra-individual, day-to-day variation. Larger inter-individual CV than intra-individual CV was more pronounced for Pb and Al. Inter- and intra-individual CVs were smaller for iAs than other metals: This may be related to the fact that the major dietary source of iAs is known to be rice (Oguri et al., 2014), a staple food of the Japanese.
Intra-individual**
Inter-individual
TAs iAs Pb Al
Arithmetic mean ± SD of 319 3-days average (μg/kg/day)
CV* %
Median CV** % (MinMax)
3.15 ± 3.04 0.322 ± 0.225 0.120 ± 0.117 65.7 ± 84.4
96.5 70.0 97.3 129
61.2 24.9 30.7 49.1
(5.4–159) (2.8–153) (1.2–138) (4.0–162)
Abbreviations: SDstandard deviation; CVcoefficient of variation. * {[Standard deviation of 319 3-days average values]/[Mean of 3-days average values]} x 100. ** Median value of {[Standard deviation of 3 days intake levels of each subject]/[mean of 3 days intake levels of each subject]} x 100 (n = 311).
3.4. Variation in daily intake according to subjects’ factors Variation in daily intake levels of TAs, iAs, Pb and Al were analyzed in relation to gender, age grade, district of Japan where the subjects’ community is located, and type of the community. In the following, statistical results on log-transformed daily intake (μg/kg/day) are presented. 3.4.1. Gender Female subjects had significantly higher geometric mean daily intake levels of TAs (p < 0.05), Pb (p < 0.01) and Al (p < 0.001) than male subjects (Table 5). The significant gender differences diminished for TAs and Pb, but remained for Al with weaker significance, when intake was not adjusted for body weight (data not shown). Daily iAs
3.3. Inter- and intra-individual variations The daily intake levels of TAs, iAs, Pb and Al shown in Table 3 were the average intake levels of 3-days diet. Meanwhile, intra-individual variation for daily TAs, iAs, Pb and Al intakes could be estimated by the standard deviations of the 3-days intake of 311 subjects whose 3-days intake data were available. Table 4 compared intra- and inter-individual variations in daily intakes of TAs, iAs, Pb and Al. Intra-individual CVs, obtained for 311 subjects, ranged from 1% to > 100%, and median CV was 25–61%. On the other hand, inter-individual CV, calculated from mean of 319 3-days average intakes and its standard deviation, was 70–130%. The larger inter-individual CV than median intra-individual CV indicated that daily intakes of TAs, iAs, Pb and Al
Table 5 Gender difference in daily intake levels*(μg/kg/day).
TAs iAs Pb Al
Male (n = 94)
Female (n = 225)
t-test
2.01 (2.27) 0.277 (1.67) 0.0822 (1.88) 34.5 (2.11)
2.45 (2.12) 0.267 (1.83) 0.102 (1.86) 51.0 (2.20)
p < 0.05 NS p < 0.01 p < 0.001
* Geometric mean with geometric standard deviation in parenthesis. 80
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Fig. 3. Daily intake of total arsenic (log-transformed) by district where the surveyed communities were located. Dot and bar in the figure denote mean and 95% confidence interval. District 1 Hokkaido/Tohoku; 2 Kanto/Koshin-etsu; 3 Tokai/Hokuriku/Kinki; 4 Chugoku/Shikoku; 5 Kyushu/Okinawa.
Fig. 1. Daily lead intake (log-transformed) by age grade. Dot and bar in the figure denote mean and 95% confidence interval, respectively. Age grade 1: < 30 yrs; 2: 30–40 yrs; 3: 40–50 yrs; 4: 50–60 yrs; 5: > 60 yrs.
intake level was higher in male than in female when intake was not adjusted for body weight. In the present subjects, weight of one-day diet was significantly greater for male than for female (mean of 3-days average: 2647 ± 679 g/day vs 2429 ± 552 g/day, Table 2). On the other hand, males had significantly heavier body weight than female (68.7 ± 9.7 kg vs 56.0 ± 9.3 kg, Table 2), and daily consumption weight of food per unit body weight was significantly greater in female (44.4 g/kg bw) than in male (39.2 g/kg bw). This should be the reason of the gender difference in metals/metalloids intake.
Nutrition Survey of 2008, conducted by the Ministry of Health, Labor and Welfare of Japan (MHLW), revealed that the average daily consumption weight of fish & shellfish of the Japanese in age category 18–29, 30–49, 50–69 and > 70 largely increased in this order (63.8 g, 67.7 g, 97.7 g, and 88.4 g) and so did seaweed (8.5 g, 9.2 g, 11.6 g, and 11.0 g) (Ministry of Health Labor and Welfare, 2009). This trend coincided with the age-related trend in daily TAs and Pb intakes observed in this study (Figs. 1 and 2). In contrast, daily consumption weight of rice and confectionery was rather constant across the age grades (Ministry of Health Labor and Welfare, 2009). 3.4.3. District Japan was divided into 5 districts in the Survey and community was selected from the districts as even as possible. Significant variation in daily TAs intake levels according to the district was found by ANOVA (p < 0.001, Fig. 3). Multiple comparison revealed significantly higher daily TAs intake in Hokkaido/Tohoku district (Tukey, p < 0.001) but no significant differences between the other districts. Although more females and more aged subjects are included in this district than in other districts (χ2 test), this significant variation in daily TAs intake was not consistent with variation in the amount of one-day diet consumption (data not shown). It is speculated that more seafood is consumed by the subjects in Hokkaido/Tohoku district than in other districts. According to the result of National Health and Nutrition Survey by MHLW, fish and shellfish consumption was greatest in Hokkaido district (96.1 g/day) and second greatest in Tohoku district (91.8 g/day) among 12 districts of Japan (grouping of districts is different from that of the present study) in 2008 (Ministry of Health Labor and Welfare, 2009). The reason of the lack of significant district-related variation in daily intake of Pb, of which intake was significantly contributed by fish & shellfish and seaweeds consumptions like TAs, would be less pronounced contribution of fish & shellfish consumption to Pb intake than to TAs intake (Hayashi et al., 2018).
3.4.2. Age-grade There was a significant variation in daily intake levels of TAs and Pb according to age grade (ANOVA, p < 0.01) (Figs. 1 and 2). For both TAs and Pb, increasing trend with aging was apparent. A similar trend was found in other countries, e.g., in Spain (Martorell et al., 2011), in which the factor(s) responsible to the trend was not discussed. The trend found in this study may be explained by the age-related trend in daily consumption weight of food categories among Japanese. Our previous study on Japanese subjects (Hayashi et al., 2018) and market basket studies of others (Sato et al., 2014; Yoshinaga et al., 2017) found major contributing food category to daily intake of the four metals/ metalloids were fish & shellfish and seaweed for TAs and Pb, rice for iAs and cereal and sugar & confectionery for Al. National Health and
3.4.4. Type of community Each year, 3 communities with different types (urban, farming and fishery) were selected for the Survey. Significant variation according to types of community was found only for daily TAs intake (ANOVA, p < 0.001) and subsequent multiple comparison revealed that daily TAs intake was higher in fishery community than in urban community (Fig. 4). No significant difference was found between farming community and fishery community. It must be noted that there was no difference in the distribution of gender and age grades by type of community (χ2 test) and no significant variation with the amount of
Fig. 2. Daily total arsenic intake (log-transformed) by age grade. Details are the same as those in the footnote to Fig. 1. 81
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Fig. 4. Daily intake of total arsenic (log-transformed) by type of community where duplicate diet samples were collected. Dot and bar in the figure denote mean and 95% confidence interval. Type of community 1 Urban; 2 Farming; 3 Fishery.
one-day diet consumption. This means that higher TAs intake in fishery community was independent of amount of diet consumption but depends on other factor(s). Greater fish and seaweed consumption in fishery community is expected, and this would most probably be the reason of higher daily TAs intake. The same reasoning as district-related variation can be postulated to the lack of significant community typerelated variation in daily Pb intake. As described above, there were several significant variations in daily intake levels of TAs, Pb and Al due to a couple of factors. The significant variations due to gender could be explained by variation in daily diet consumption amount per body weight: greater diet consumption amount in female and in elder subjects were associated with greater daily TAs, Pb, and Al intakes in them. Greater daily TAs intake in the people in elder age grade, that in Hokkaido/Tohoku district and that in fishery community was independent of the amount of diet consumption and significant difference in food preference from that of the subjects of other age grades/districts/types of community was suggested.
References Arnich, N., Sirot, V., Rivière, G., Jean, J., Noël, L., Guérin, T., Leblanc, J.-C., 2012. Dietary exposure to trace elements and health risk assessment in the 2nd French Total Diet Study. Food Chem. Toxicol. 50, 2432–2449. Awata, H., Linder, S., Mitchell, L.E., Delclos, G.L., 2017. Association of dietary intake and biomarker levels of arsenic, cadmium, lead, and mercury among Asian populations in the United States: NHANES 2011–2012. Environ. Health Perspect. 125, 314–323. Callan, A., Hinwood, A., Devine, A., 2014. Metals in commonly eaten groceries in Western Australia: a market basket survey and dietary assessment. Food Addit. Contam. Part A 31, 1968–1981. Cubadda, F., D’Amato, M., Aureli, F., Raggi, A., Mantovani, A., 2016. Dietary exposure of the Italian population to inorganic arsenic: the 2012–2014 Total Diet Study. Food Chem. Toxicol. 98, 148–158. Domingo, J.L., Perelló, G., Bordonaba, J.G., 2012. Diatery intake of metals by the population of Tarragona County (Catalonia, Spain): results from a duplicate diet study. Biol. Trace Elem. Res. 146, 420–425. Falcó, G., Llobet, J.M., Bocio, A., Domingo, J.L., 2006. Daily intake of arsenic, cadmium, mercury, and lead by consumption of edible marine species. J. Agric. Food Chem. 54, 6106–6112. Fekete, V., Vandevijvere, S., Bolle, F., Van Loco, J., 2013. Estimation of dietary aluminum exposure of the Belgian adult population: evaluation of contribution of food and kitchenware. Food Chem. Toxicol. 55, 602–608. Hayashi, A., Sato, F., Imai, T., Yoshinaga, J., 2018. Statistical approach to identify food categories that determine daily intake levels of total and inorganic arsenic, lead and aluminium of Japanese diet. Food Addit. Contam. Part A 35, 1749–1754. Japan Food Research Laboratories, 2014. Analysis Report of Chemical and Contaminant Content in Duplicate Diet Samples of 2012 Fiscal Year (The Present Authors’ Translation). Tokyo, Japan (In Japanese). . JECFA, 2011a. Evaluation of Certain Food Additives and Contaminants: Seventy-Second Report of the Joint FAO/WHO Expert Committee on Food Additives, World Health Organization Technical Report Series 959. pp. 21–37. JECFA, 2011b. Evaluation of Certain Food Additives and Contaminants: Seventy-Third Report of the Joint FAO/WHO Expert Committee on Food Additives, World Health Organization Technical Report Series 960. pp. 176–177. JECFA, 2011c. Evaluation of Certain Food Additives and Contaminants: Seventy-Fourth Report of the Joint FAO/WHO Expert Committee on Food Additives, World Health Organization Technical Report Series 966. pp. 7–17. Liu, P., Wang, C.-N., Song, X.-Y., Yu, Y.-F., Wu, Y.-N., 2010. Dietary intake of arsenic by children nd adults from Jinhu area of China. Food Addit. Contam. 27, 1128–1135. Llobet, J.M., Falcó, G., Casas, C., Teixidó, A., Domingo, J.L., 2003. Concentrations of arsenic, cadmium, mercury, and lead in common foods and estimated daily intake by children, adolescences, adults, and seniors in Catalonia, Spain. J. Agric. Food Chem. 51, 838–842. Luo, J., Meng, J., Ye, Y., Wang, Y., Bai, L., 2018. Population health risk via dietary exposure to trace elements (Cu, Zn, Pb, Cd, Hg, and As) in Qiqihar, Northeastern China. Environ. Geochem. Health 40, 217–227. Martorell, I., Perelló, G., Martí-Cid, R., Llobet, J.M., Castell, V., Domingo, J.L., 2011. Human exposure to arsenic, cadmium, mercury, and lead from foods in Catalonia, Spain: temporal trend. Biol. Trace Elem. Res. 142, 309–322. Ministry of Health Labor and Welfare, 2009. Result of 2008 National Nutrition and Health Survey. Retrieved December 19, 2018 from. http://www.mhlw.go.jp/bunya/ kenkou/eiyou/h20-houkoku.html. Ministry of the Environment, 2012. The Exposure to Dioxins and Other Chemical
4. Conclusion Duplicated diet samples obtained from 319 adult subjects from all over Japan for 3 consecutive days were analyzed for TAs, iAs, Pb and Al contents. The obtained results for daily intake of these 4 metals/metalloids are regarded as representative of the general Japanese people. Inter-individual variations in the daily intake levels according to gender was mostly explained by daily food consumption amount (more metal/ metalloid intake for the person who consumed more food) except for TAs, of which intake was more in elder aged persons, northern part of Japan and/or in fishery communities, which may be explained by more fish and shellfish and seaweed consumption. The present result will be valuable for the exposure assessment of the Japanese in assessing the health risk. Acknowledgements The authors thank Ministry of the Environment for providing duplicate diet samples and Y. Chisaki and M. Hijiya of IDEA Consultants Inc. for providing with information on the samples. This study was partly supported by a grant from the Food Safety Commission, Cabinet Office, Government of Japan (Research Program for Risk Assessment Study on Food Safety, No. 1704). 82
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Sato, K., Suzuki, I., Kubota, H., Furusho, N., Inoue, T., Yasukouchi, Y., Akiyama, H., 2014. Estimation of daily aluminum intake in Japan based on food consumption inspection results: impact of food additives. Food Sci. Nutr. 2, 389–397. Škrbić, B., Živančev, J., Mrmoš, N., 2013. Concentrations of arsenic, cadmium and lead in selected foodstuffs from Serbian market basket: estimated intake by the population from the Serbia. Food Chem. Toxicol. 58, 440–448. Tokyo Metropolitan Government, 2017. Estimated Daily Intake of Chemicals via the Diet. Retrieved December 19, 2018 from (in Japanese). http://www.metro.tokyo.jp/tosei/ hodohappyo/press/2017/08/02/documents/08_01.pdf. Tsuda, T., Inoue, T., Kojima, M., Aoki, S., 1995. Market basket and duplicate portion estimation of dietary intake of cadmium, mercury, arsenic, copper, manganese, and zinc by Japanese adults. J. AOAC Int. 78, 1363–1368. Wong, W.W.K., Chung, S.W.C., Kwong, K.P., Ho, Y.Y., Xiao, Y., 2010. Dietary exposure to aluminium of the Hong Kong population. Food Addit. Contam. 27, 457–463. Wong, W.W., Chung, S.W., Chan, B.T., Ho, Y.Y., Xiao, Y., 2013. Dietary exposure to inorganic arsenic of the Hong Kong population: results of the first Hong Kong total diet study. Food Chem. Toxicol. 51, 379–385. Yamauchi, H., Takahashi, K., Mashiko, M., Saitoh, J., Yamamura, Y., 1992. Intake of different chemical species of dietary arsenic by the Japanese, and their blood and urinary arsenic levels. Appl. Organomet. Chem. 6, 383–388. Yang, M., Jiang, L., Huang, H., Zeng, S., Qiu, F., Yu, M., Li, X., Wei, S., 2014. Dietary exposure to aluminium and health risk assessment in the residents of Shenzhen, China. Plos One 9 e89715. Yoshinaga, J., Al Amin, M.H., Oguri, T., 2017. Daily dietary lead exposure estimated based on market basket survey. J. Environ. Chem. 27, 171–175.
Compounds in the Japanese People. Retrieved December 19, 2018 from. http:// www.env.go.jp/chemi/dioxin/pamph/cd/en_full.pdf. Mohri, T., Hisanaga, A., Ishinishi, N., 1990. Arsenic intake and excretion by Japanese adults: a 7-day duplicate diet study. Food Chem. Toxicol. 28, 521–529. Narukawa, T., Kuroiwa, T., Inagaki, K., Takatsu, A., Chiba, K., 2010. Heat-assisted aqueous extraction of rice flour for arsenic speciation analysis. J. Agric. Food Chem. 58, 8183–8188. National Institute of Health Sciences (NIHS), 2008. Daily Intake of Contaminants in Foods Based on Market Basket Samples: 1977–2007 (The Present Authors’ Translation). Tokyo, Japan (In Japanese). . Nishimura, T., Hamano-Nagaoka, M., Sakakibara, N., Abe, T., Maekawa, Y., Maitani, T., 2010. Determination method for total arsenic and partial-digestion method with nitric acid for inorganic arsenic speciation in several varieties of rice. J. Food Hyg. Soc. Jpn. 51, 178–181. Oguri, T., Yoshinaga, J., Tao, H., Nakazato, T., 2012. Daily intake of inorganic arsenic and some organic arsenic species of Japanese subjects. Food Chem. Toxicol. 50, 2663–2667. Oguri, T., Yoshinaga, J., Tao, H., Nakazato, T., 2014. Inorganic arsenic in the Japanese diet: daily intake and source. Arch. Environ. Contam. Toxicol. 66, 100–112. Rahmdel, S., Abdollahzadeh, S.M., Mazloomi, S.M., Babajafari, S., 2015. Daily dietary intakes of zinc, copper, lead, and cadmium as determined by duplicate portion sampling combined with either instrumental analysis or the use of food composition tables, Shiraz, Iran. Environ. Monit. Assess. 187, 349. Rose, M., Baxter, M., Brereton, N., Baskaran, C., 2010. Dietary exposure to metals and other elements in the 2006 UK Total Diet Study and some trends over the last 30 years. Food Addit. Contam. 27, 1380–1404.
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Journal of Food Composition and Analysis journal homepage: www.elsevier.com/locate/jfca
Daily intake of total and inorganic arsenic, lead, and aluminum of the Japanese: Duplicate diet study☆ Akiko Hayashia,1, Fumio Satoa,2, Tomoko Imaia,3, Jun Yoshinagab, a b
T
⁎
Food Safety Commission, 5-2-20 Akasaka, Minato, Tokyo, 107-6122, Japan Faculty of Life Sciences, Toyo University. 1-1-1 Izumino, Itakura, Oura, Gunma, 394-0193, Japan
A R T I C LE I N FO
A B S T R A C T
Keywords: Duplicate diet Total arsenic Inorganic arsenic Lead Aluminum
Daily intakes of total (TAs) and inorganic arsenic (iAs), lead (Pb) and aluminum (Al) of the Japanese were estimated by the analysis of duplicated diet samples. The samples were collected for 3 consecutive days from 319 subjects (total number: 949) living in Japan during 2006–2010 by the Ministry of the Environment of Japan. TAs, Pb and Al concentrations in duplicated diet samples, determined by ICP mass spectrometry (ICP-MS) preceded by a microwave acid digestion, and iAs was by liquid chromatography-ICP-MS preceded by an acidic extraction, were used for this study. Median 3-days average intake was calculated to be 2.31, 0.260, 0.0928, and 41.1 μg/kg/day, for TAs, iAs, Pb and Al, respectively (138, 15.3, 5.40, and 2363 μg/person/day). The daily intake levels were found to vary according to subjects’ gender (TAs, Pb, and Al), but this was explained by variation in the amount of daily food consumption. Daily TAs intake was found to vary with age grade, districts where community is located and types (urban/farming/fishing) of community, probably reflecting fish/seaweed consumption.
1. Introduction Metals and metalloids are ubiquitous in the environment with both natural and anthropogenic origins. They are present in food to be the major source for human exposure. Since the exposure to some of the metals and metalloids are known to be closely related to human health and diseases, dietary intake levels of such metals and metalloids have been a matter of concern in the field of environmental science, nutritional science, food safety and others. In this publication, daily dietary intake levels of total arsenic (TAs), inorganic arsenic (iAs), lead (Pb) and aluminum (Al) of the general Japanese people are presented. These metals and metalloids were selected because they have been attracting interest in the risk assessment bodies: Provisional Tolerable Weekly Intakes (PTWIs) for Pb and As, once set by JECFA in the past, were withdrawn in 2010, because the PTWIs were found not suitable for preventing health effects (JECFA, 2011a,b). On the other hand, in 2011, JECFA has set a renewed PTWI for Al to be 2 mg/kg/week (formerly 1 mg/kg/week) based on the re-
assessment of Al health risk (JECFA, 2011c). In response to the evaluations of JECFA on the risks of these metals and metalloids, other bodies started assessment/reassessment of the risks. Food Safety Commission of Japan (FSCJ) is one of such bodies and has recently assessed health risk of As in food. Risks of Pb and Al are currently under assessment. During the assessment of FSCJ, it has been recognized that reliable data on daily intake of As, Pb, and Al of the Japanese are not abundant. It was particularly so for iAs and Pb: iAs intake data are limited not only in Japan but also worldwide, probably due to analytical difficulty, though that on TAs was relatively abundant (e.g., Falcó et al., 2006; National Institute of Health Sciences (NIHS), 2008; Liu et al., 2010; Domingo et al., 2012; Luo et al., 2018). Daily intake of Pb of the Japanese have been reported, however, variation among the reports were large possibly reflecting downward changes of Pb levels in foods with time (National Institute of Health Sciences (NIHS), 2008), which might be also accompanied with technical problems in the analysis of Pb and calculation of daily intake (e.g., inclusion/exclusion of non-detectable
☆
The views expressed in this paper do not necessarily represent positions or policy of Food Safety Commission of Japan. Corresponding author. E-mail address: [email protected] (J. Yoshinaga). 1 Present address at Japan Agency for Medical Research and Development. Muromachi Chibagin Mitsui Bldg, 1-5-5 Nihonbashi-Muromachi, Chuo, Tokyo 1030022, Japan. 2 Present address at Fisheries Agency Niigata Fisheries Coordination Office. 1-5-15 Yachiyo, Chuo-ku, Niigata, Niigata 950-0909, Japan. 3 Present address at Tokyo Quarantine Station. Tokyo Kowan Godochosha, 2-7-11 Aomi, Koto, Tokyo 135-8615, Japan. ⁎
https://doi.org/10.1016/j.jfca.2019.01.009 Received 19 December 2017; Received in revised form 26 December 2018; Accepted 18 January 2019 Available online 22 January 2019 0889-1575/ © 2019 Elsevier Inc. All rights reserved.
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HNO3 (Kanto Chemicals Co. Ltd., Tokyo, Japan) and H2O2 (Atomic Absorption Grade, Kanto Chemicals) in microwave digestion systems (ETHOS TC or Ultra Wave, Milestone General Co. Ltd., Yokohama, Japan). After digestion, acetic acid (Reagent Grade, Kanto Chemicals) was added for the compensation of carbon interference on As and made up to 50 g with MQ water. TAs, Pb and Al concentrations in the digested samples were determined by ICP mass spectrometry (ICP-MS) (Agilent 7500ce and 8800, Agilent Technologies, Tokyo, Japan). ICP-MS was operated under helium collision mode and by using gallium (for Al), tellurium (for TAs), and thallium (for Pb) as internal standards. For the analysis of iAs, 2 g of sample was extracted with 10 mL of 0.3 mol/L HNO3 in a test tube at 100 °C for 2 h according to Nishimura et al. (2010) with a modification. After centrifugation, the supernatant was recovered and then the residue was washed with 5 mL of MQ, which was recovered and combined with the dilute HNO3 supernatant. The pH of the combined supernatant was adjusted to 3 with NH4OH, and then the volume was made up to 20 mL. The solution was filtered through 0.45 μm cellulose membrane filter and 20 μL of it was injected into a liquid chromatography-ICP-MS (LC-ICP-MS) system for As speciation analysis. The separation of As compounds by the LC (Agilent 1200 Series, Agilent Technologies, Co. Ltd.) was based on ion-pair reversed phase mode (Narukawa et al., 2010) using CAPCELL PAK C18 MG (4.6 mm I.D. × 250 mm) (Shiseido Co. Ltd. Tokyo, Japan). As(V), As(III), methylarsonic acid, dimethylarsinic acid, arsenobetaine, trimethylarsine oxide, and tetramethylarsonium ion were separated and determined. Since valence of iAs (As(V) and As(III)) could change during the acid extraction, the sum of As(III) and As(V) concentrations was taken as iAs in this study. The analytical results of the duplicate diet samples were compiled in a report (Japan Food Research Laboratories, 2014).
samples). As a result, reliable recent data on daily Pb intake is limited. In this study, a particular care was paid to analytical quality assurance so that reliable daily intake information is available for risk assessors. Although daily intake levels of metals/metalloids in a population are domestic/local issue, it is indispensable in the risk assessment of the metal in that particular country/area, which will be referenced in the assessment in other countries. 2. Materials and methods 2.1. Duplicate diet samples Duplicate diet samples analyzed in this study were obtained from the participants in the monitoring programs “Survey of the Exposure to Dioxins and Other Chemical Compounds in Humans” (2006–2010) conducted by the Ministry of the Environment of Japan (Ministry of the Environment of Japan, 2012). In the survey, one prefecture was selected from each of 5 districts of Japan (Hokkaido/Tohoku, Kanto/ Koshin-etsu, Tokai/Hokuriku/Kinki, Chugoku/Shikoku, Kyushu/Okinawa in the order of north to south of Japan Archipelago), and 3 different types of community, i.e., urban, farming, and fishery community, were selected from each of the Prefecture in each year during 20062008. During 2009–2010, urban and fishery communities were selected from each Prefecture. Fifteen to twenty participants were recruited for the Survey from each community each year whose blood samples were measured for organic contaminants. Among the participants, 5 in each community supplied duplicate diet samples for 3 consecutive days each year. In total, 325 participants of the survey supplied duplicate diet samples. Total weight of one day duplicate diet was recorded. The duplicate diet samples were individually homogenized in a food processor and stored in freezer. An aliquot of the frozen sample was subject to TAs, iAs, Pb, and Al analyses. Leaching test did not detect As, Pb and Al from the processer. For this study duplicate diet samples from 319 participants were available: 6 samples were missing for various reasons.
2.4. Analytical quality control Analytical quality was verified both internally and externally. Blanks and in-house control material with food matrix was run in each batch of measurements. Linearity of calibration curves were checked at every measurement. Lower limit of detection of TAs, iAs, Pb and Al as expressed in the concentrations in duplicate diet sample were 0.00008, 0.0013, 0.0003 and 0.03 μg/g, respectively, which roughly corresponded to 0.2, 3, 0.7 and 75 μg as daily intake/person, respectively. Accuracy of the analyses was confirmed by the analysis of certified reference materials, i.e., NIST SRM 1548a Typical Diet, NIST SRM 1568a Rice Flour, IRMM 804 Rice Flour, and NMIJ CRM 7503 Rice Flour for TAs, Pb and Al, and NMIJ CRM 7503-a White Rice Flour and NMIJ CRM 7405-a Hijiki for iAs. As presented in Table 1, the measured values were in accordance with the certified values of the CRMs with small standard deviations indicating that the trueness and precision of
2.2. Subject’s information Gender, age grade (10-yrs interval), and body weight of the subject, who supplied 3-days duplicate diet samples, was obtained for this study from the questionnaire data of the survey. 2.3. Analytical methods Analysis of TAs, iAs, Pb and Al was carried out at a commercial laboratory, Japan Food Research Laboratories (Tokyo, Japan). Two grams of thawed duplicate diet sample was digested with Ultrapure Table 1 Analytical Results (unit: mg/kg) of Certified Reference Materials$.
NIST SRM 1548a NIST SRM 1598a IRMM 804 NMIJ CRM 7503 NMIJ CRM 7503-a NMIJ CRM 7405-a
Measured Certified Measured Certified Measured Certified Measured Certified Measured Certified* Measured Certified#
TAs
Pb
Al
0.198 ± 0.001 0.2 ± 0.01 0.262 ± 0.007 0.29 ± 0.03 0.0502 ± 0.002 0.049 ± 0.005 0.0986 ± 0.0001 0.098 ± 0.007
0.049 ± 0.002 0.044 ± 0.009
72.3 ± 0.3 72.4 ± 1.52 4.54 ± 0.11 4.4 ± 1.0
iAs
0.414 ± 0.012 0.42 ± 0.07
0.0870 ± 0.0003 0.0841 ± 0.0068 10.2 ± 0.2 10.1 ± 0.5
$
Mean ± SD of 3 replicate analyses are shown. * Sum of the certified values for As(III) (0.0711 ± 0.0029 mg/kg) and As(V) (0.0130 ± 0.0009 mg/kg) with combined uncertainty is shown. # Certified value is based on iAs extracted in water. 78
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our analyses were satisfactory.
Table 2 Characteristics of the subjects who donated duplicate diet samples (n = 319).
2.5. Data analysis
Attribute Gender Male Female Age grade < 20 20–30 30–40 40–50 50–60 60–70 ≥70 District of the community where subjects reside* Hokkaido/Tohoku Kanto/Koushin-etsu Tokai/Hokuriku/Kinki Chugoku/Shikoku Kyushu/Okinawa Type of the community Urban Farming Fishery
TAs, iAs, Pb and Al concentrations in 949 duplicate diet samples from 319 subjects (one missing sample for each of 8 subjects was present) were obtained from ICP-MS and LC-ICP-MS analyses and they were analyzed in this study as follows. The concentration (μg/g) was multiplied by the total amount of the diet sample (g/day) to produce daily intake of the element. In this study, daily intake of the element is basically expressed as μg/kg body weight/day by dividing daily intake by the body weight of the subject. Further, mean of the 3 days intake (mean of two for the 8 subjects with missing data) was taken as the subject’s average intake: thus 319 3-days (or 2-days) average daily intakes for each of TAs, iAs, Pb, and Al are available and used in this study. The standard deviation of the 3-days intakes for each subject was divided by the corresponding 3-days average value to produce coefficient of variation (CV, %) for each of the subjects, which were regarded as intra-individual (between-day) variation. Note that standard deviation and CV for 8 subjects who had 2-days intake data was not calculated. Thus, intra-individual variation CV was obtained for 311 subjects. In contrast, the standard deviation of 319 3-days average values divided by the mean of the 3-days average was regarded as inter-individual variation CV (%). The two CV values were compared. The daily intakes of metals/metalloids distributed log-normally: logtransformed value was used for statistical analysis to compare daily intake between gender (t-test) and those to compare among age grades, 5 districts of Japan where the community is located, and 3 types of the community (one-way analysis of variance, ANOVA). Subjects’ attributes are shown in Table 1. Since the number of < 20 yrs and > 70 yrs subjects was 3 and 1, respectively (Table 1), the < 20 yrs subjects were included in 20–30 yrs age grade and the > 70 yrs subject was in 60–70 age grade, respectively, for age-grade based analysis. SPSS ver. 19 J (IBM Co. Ltd., Tokyo, Japan) was used for statistical analyses.
Body weight (kg) Male Female Weight of one-day duplicate diet sample (g) Male Female
Number
(%)
94 225
(29.5) (70.5)
3 25 59 63 97 71 1
(0.9) (7.8) (18.5) (19.7) (30.4) (22.3) (0.3)
54 73 74 64 54
(16.9) (22.9) (23.2) (20.1) (16.9)
124 95 100 Mean 59.7 68.7 56.0 2493 2647 2429
(38.9) (29.8) (31.3) ± SD ± 11.0 ± 9.7 ± 9.3 ± 646 ± 679 ± 552
* In the order of northern to southern part of Japan Archipelago.
2008). The present result (median 138 μg/person/day) is in agreement with these values. Tsuda et al. (1995) reported higher TAs daily intake (210–260 μg/person/day) based on duplicate diet study. In other countries, generally lower daily intakes have been reported. Higher daily TAs intakes in Japan and some European countries, such as Spain (Llobet et al., 2003; Domingo et al., 2012), are due to greater consumption of fish and seaweeds, which contains high levels of As.
3. Results and discussion 3.1. Subjects
3.2.2. iAs Three duplicate diet studies reported arithmetic mean iAs intake levels of 6.5–33.7 μg/person/day for Japanese populations with a limited number of subjects (Mohri et al., 1990; Yamauchi et al., 1992; Oguri et al., 2012) and one market basket study reported 21 μg/person/ day on bioaccessible fraction basis or 24 μg/person/day on total iAs basis (Oguri et al., 2014). The present result (median 15.3 μg/person/ day) was in accordance with these reported values. These levels were below PTWI for As (15 μg/kg/week or 129 μg/person of 60 kg body weight/day) which was withdrawn in 2010 because it was no longer health protective (JECFA, 2011b). Lower daily iAs intake levels were found in other countries: 2.1–5.6 μg/person/day in Italy (Cubadda et al., 2016) and 1.4–7 μg/ person/day in the UK (Rose et al., 2010) were reported with total diet study design while similar value (13.4 μg/person/day) to the present study was reported in Hong Kong (Wong et al., 2013). Consumption of rice as staple food would be the contributing factor of higher daily iAs intake in Asian countries including Japan.
Table 2 shows demographic characteristics of the 319 subjects. There were 94 male and 225 female subjects. All of them were adult (> 20 yrs old) except for 3 subjects. The subjects were selected from 5 districts of Japan fairly evenly, and so did from 3 different types of community. 3.2. Daily intake levels of TAs, iAs, Pb and Al of the Japanese Table 3 shows distribution of daily intakes of TAs, iAs, Pb and Al (3days average) of the 319 subjects. Minimum, maximum, and 5–95 percentile values, as well as geometric mean values, are presented. Daily intakes per person are also presented for the comparison with published data. There were 8 undetectable samples only for iAs: lower limit of detection could be converted to intake level of 3 μg/person/day or 0.05 μg/kg/day. For the undetectable samples, 1/2 of the converted lower limit of detection intake was substituted for the calculation of the mean value. The daily intakes obtained in the present study were generally in agreement with the recently published intakes of the Japanese subjects but some differences are also found when compared with intake levels reported in other countries.
3.2.3. Pb Higher daily Pb intake (up to 100 μg/person/day) was reported in earlier market basket studies carried out in Japan in 1970s (National Institute of Health Sciences (NIHS), 2008). This was certainly due to more severe environmental contamination with Pb in those days of Japan. Daily Pb intakes thus expected to be variable depending on the time of survey. Most recent market basket survey by the Tokyo Metropolitan Government (2017) and that by Yoshinaga et al. (2017) reported 0.082 μg/kg/day and 4.69 μg/person/day, respectively, which
3.2.1. TAs National Institute of Health Science of Japan (NIHS) has been compiling data from market basket surveys carried out in Japan: during 2000–2007, yearly average daily intakes of TAs were recorded as 145–186 μg/person/day (National Institute of Health Sciences (NIHS), 79
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Table 3 Distribution of daily intakes of TAs, iAs, Pb and Al of the Japanese* (n = 319). Min
Intake per person (μg/person/day) TAs 11.0 iAs <3 Pb 0.73 Al (mg) 0.32
Percentile
Max
Geometric Mean
Geometric SD
5
25
50
75
95
37.9 6.87 2.17 0.84
85.3 10.8 3.90 1.64
138 15.3 5.40 2.36
226 22.0 7.87 4.27
437 45.2 17.3 11.1
1366 99.4 64.8 61.1
136 15.9 5.61 2.67
2.15 1.78 1.84 2.16
1.42 0.185 0.0634 27.1
2.31 0.260 0.0928 41.1
3.89 0.382 0.135 74.8
8.08 0.833 0.319 179
22.8 1.50 1.22 985
2.31 0.270 0.0955 45.4
2.19 1.78 1.88 2.21
Intake per body weight (μg/kg/day) TAs 0.20 0.60 iAs < 0.05 0.110 Pb 0.0120 0.0390 Al 5.7 14.7
* Distribution of the 3-days average intake.
are in good agreement with the present result (median 0.0928 μg/kg/ day or 5.40 μg/person/day). These levels are well below the withdrawn PTWI for Pb (25 μg/kg/week or 214 μg/person of 60 kg body weight/ day). Similar daily intakes to that in this study have been reported in other countries in the last five years: A French total diet study reported mean daily Pb intake of adult and children to be 0.2 and 0.27 μg/kg/ day (Arnich et al., 2012) and Australian market basket study found 0.10.2 μg/kg/day for children (Callan et al., 2014). The US National Health and Nutrition Examination Survey found 0.087-0.107 μg/kg/day for different ethnic populations in the US (Awata et al., 2017). Much higher intake levels were reported in China (2.01 μg/kg/day; Luo et al., 2017), Iran (671 μg/person/day; Rahmdel et al., 2015), and Serbia (72.3 μg/ person/day; Škrbić et al., 2013). In this respect, daily intake level of the Japanese is thought to be among the lowest in the world.
Table 4 Inter- and intra-individual variation.
3.2.4. Al A recent market basket study in Japan reported Al intake from processed and unprocessed foods of 7 categories (Sato et al., 2014). The sum of the intakes from all of the categories showed Al intake of 2.53 mg/person/day for adult (> 20 yrs old) and 2.85 mg/person/day for youth (15–19 yrs old). Lower intake was calculated for young children (7–14 yrs old, 1.98 mg/person/day) and children (1–6 yrs old, 2.35 mg/kg/day). This result for adult is in good agreement with the present result (median 2.36 mg/person/day). A Belgian study estimated adult daily intake of Al to be 0.030 mg/ kg/day which was based on a statistical model of food consumption and measured Al concentrations in pooled foods (Fekete et al., 2013) and this was in agreement with the present result (41.1 μg/kg/day or 0.041 mg/kg/day). Somewhat higher daily intakes of Chinese adult (0.462–1.065 mg/kg/week or 0.066-0.152 mg/kg/day; Yang et al., 2014) and Hong Kong adult (0.60 mg/kg/week or 0.086 mg/kg/day; Wong et al., 2010) were reported. The daily Al intake levels reported in these publications including ours were below the PTWI set by JECFA in 2011 (2 mg/kg/week or 0.286 mg/kg/day).
varied according more to personal preferences in food consumption than to intra-individual, day-to-day variation. Larger inter-individual CV than intra-individual CV was more pronounced for Pb and Al. Inter- and intra-individual CVs were smaller for iAs than other metals: This may be related to the fact that the major dietary source of iAs is known to be rice (Oguri et al., 2014), a staple food of the Japanese.
Intra-individual**
Inter-individual
TAs iAs Pb Al
Arithmetic mean ± SD of 319 3-days average (μg/kg/day)
CV* %
Median CV** % (MinMax)
3.15 ± 3.04 0.322 ± 0.225 0.120 ± 0.117 65.7 ± 84.4
96.5 70.0 97.3 129
61.2 24.9 30.7 49.1
(5.4–159) (2.8–153) (1.2–138) (4.0–162)
Abbreviations: SDstandard deviation; CVcoefficient of variation. * {[Standard deviation of 319 3-days average values]/[Mean of 3-days average values]} x 100. ** Median value of {[Standard deviation of 3 days intake levels of each subject]/[mean of 3 days intake levels of each subject]} x 100 (n = 311).
3.4. Variation in daily intake according to subjects’ factors Variation in daily intake levels of TAs, iAs, Pb and Al were analyzed in relation to gender, age grade, district of Japan where the subjects’ community is located, and type of the community. In the following, statistical results on log-transformed daily intake (μg/kg/day) are presented. 3.4.1. Gender Female subjects had significantly higher geometric mean daily intake levels of TAs (p < 0.05), Pb (p < 0.01) and Al (p < 0.001) than male subjects (Table 5). The significant gender differences diminished for TAs and Pb, but remained for Al with weaker significance, when intake was not adjusted for body weight (data not shown). Daily iAs
3.3. Inter- and intra-individual variations The daily intake levels of TAs, iAs, Pb and Al shown in Table 3 were the average intake levels of 3-days diet. Meanwhile, intra-individual variation for daily TAs, iAs, Pb and Al intakes could be estimated by the standard deviations of the 3-days intake of 311 subjects whose 3-days intake data were available. Table 4 compared intra- and inter-individual variations in daily intakes of TAs, iAs, Pb and Al. Intra-individual CVs, obtained for 311 subjects, ranged from 1% to > 100%, and median CV was 25–61%. On the other hand, inter-individual CV, calculated from mean of 319 3-days average intakes and its standard deviation, was 70–130%. The larger inter-individual CV than median intra-individual CV indicated that daily intakes of TAs, iAs, Pb and Al
Table 5 Gender difference in daily intake levels*(μg/kg/day).
TAs iAs Pb Al
Male (n = 94)
Female (n = 225)
t-test
2.01 (2.27) 0.277 (1.67) 0.0822 (1.88) 34.5 (2.11)
2.45 (2.12) 0.267 (1.83) 0.102 (1.86) 51.0 (2.20)
p < 0.05 NS p < 0.01 p < 0.001
* Geometric mean with geometric standard deviation in parenthesis. 80
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Fig. 3. Daily intake of total arsenic (log-transformed) by district where the surveyed communities were located. Dot and bar in the figure denote mean and 95% confidence interval. District 1 Hokkaido/Tohoku; 2 Kanto/Koshin-etsu; 3 Tokai/Hokuriku/Kinki; 4 Chugoku/Shikoku; 5 Kyushu/Okinawa.
Fig. 1. Daily lead intake (log-transformed) by age grade. Dot and bar in the figure denote mean and 95% confidence interval, respectively. Age grade 1: < 30 yrs; 2: 30–40 yrs; 3: 40–50 yrs; 4: 50–60 yrs; 5: > 60 yrs.
intake level was higher in male than in female when intake was not adjusted for body weight. In the present subjects, weight of one-day diet was significantly greater for male than for female (mean of 3-days average: 2647 ± 679 g/day vs 2429 ± 552 g/day, Table 2). On the other hand, males had significantly heavier body weight than female (68.7 ± 9.7 kg vs 56.0 ± 9.3 kg, Table 2), and daily consumption weight of food per unit body weight was significantly greater in female (44.4 g/kg bw) than in male (39.2 g/kg bw). This should be the reason of the gender difference in metals/metalloids intake.
Nutrition Survey of 2008, conducted by the Ministry of Health, Labor and Welfare of Japan (MHLW), revealed that the average daily consumption weight of fish & shellfish of the Japanese in age category 18–29, 30–49, 50–69 and > 70 largely increased in this order (63.8 g, 67.7 g, 97.7 g, and 88.4 g) and so did seaweed (8.5 g, 9.2 g, 11.6 g, and 11.0 g) (Ministry of Health Labor and Welfare, 2009). This trend coincided with the age-related trend in daily TAs and Pb intakes observed in this study (Figs. 1 and 2). In contrast, daily consumption weight of rice and confectionery was rather constant across the age grades (Ministry of Health Labor and Welfare, 2009). 3.4.3. District Japan was divided into 5 districts in the Survey and community was selected from the districts as even as possible. Significant variation in daily TAs intake levels according to the district was found by ANOVA (p < 0.001, Fig. 3). Multiple comparison revealed significantly higher daily TAs intake in Hokkaido/Tohoku district (Tukey, p < 0.001) but no significant differences between the other districts. Although more females and more aged subjects are included in this district than in other districts (χ2 test), this significant variation in daily TAs intake was not consistent with variation in the amount of one-day diet consumption (data not shown). It is speculated that more seafood is consumed by the subjects in Hokkaido/Tohoku district than in other districts. According to the result of National Health and Nutrition Survey by MHLW, fish and shellfish consumption was greatest in Hokkaido district (96.1 g/day) and second greatest in Tohoku district (91.8 g/day) among 12 districts of Japan (grouping of districts is different from that of the present study) in 2008 (Ministry of Health Labor and Welfare, 2009). The reason of the lack of significant district-related variation in daily intake of Pb, of which intake was significantly contributed by fish & shellfish and seaweeds consumptions like TAs, would be less pronounced contribution of fish & shellfish consumption to Pb intake than to TAs intake (Hayashi et al., 2018).
3.4.2. Age-grade There was a significant variation in daily intake levels of TAs and Pb according to age grade (ANOVA, p < 0.01) (Figs. 1 and 2). For both TAs and Pb, increasing trend with aging was apparent. A similar trend was found in other countries, e.g., in Spain (Martorell et al., 2011), in which the factor(s) responsible to the trend was not discussed. The trend found in this study may be explained by the age-related trend in daily consumption weight of food categories among Japanese. Our previous study on Japanese subjects (Hayashi et al., 2018) and market basket studies of others (Sato et al., 2014; Yoshinaga et al., 2017) found major contributing food category to daily intake of the four metals/ metalloids were fish & shellfish and seaweed for TAs and Pb, rice for iAs and cereal and sugar & confectionery for Al. National Health and
3.4.4. Type of community Each year, 3 communities with different types (urban, farming and fishery) were selected for the Survey. Significant variation according to types of community was found only for daily TAs intake (ANOVA, p < 0.001) and subsequent multiple comparison revealed that daily TAs intake was higher in fishery community than in urban community (Fig. 4). No significant difference was found between farming community and fishery community. It must be noted that there was no difference in the distribution of gender and age grades by type of community (χ2 test) and no significant variation with the amount of
Fig. 2. Daily total arsenic intake (log-transformed) by age grade. Details are the same as those in the footnote to Fig. 1. 81
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Fig. 4. Daily intake of total arsenic (log-transformed) by type of community where duplicate diet samples were collected. Dot and bar in the figure denote mean and 95% confidence interval. Type of community 1 Urban; 2 Farming; 3 Fishery.
one-day diet consumption. This means that higher TAs intake in fishery community was independent of amount of diet consumption but depends on other factor(s). Greater fish and seaweed consumption in fishery community is expected, and this would most probably be the reason of higher daily TAs intake. The same reasoning as district-related variation can be postulated to the lack of significant community typerelated variation in daily Pb intake. As described above, there were several significant variations in daily intake levels of TAs, Pb and Al due to a couple of factors. The significant variations due to gender could be explained by variation in daily diet consumption amount per body weight: greater diet consumption amount in female and in elder subjects were associated with greater daily TAs, Pb, and Al intakes in them. Greater daily TAs intake in the people in elder age grade, that in Hokkaido/Tohoku district and that in fishery community was independent of the amount of diet consumption and significant difference in food preference from that of the subjects of other age grades/districts/types of community was suggested.
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