Ⅲ. RESULTS AND DISCUSSION
3.4 Dietary intake
3.4.1 Dietary intake of PCNs
In order to lessen underestimate of dietary intake of PCNs, MFDS data for 8 livestock products and 20 fishery products were added to calculation (MFDS, 2019b). The concentration of 11 congeners (CN-52, 53, 66, 68, 69, 71, 72, 63, 73, 74, and 75) from additional data are listed in Table S4. To avoid misinterpretation of the data due to the difference in the number of congeners, Σ11 TEQPCN or Σ20 TEQPCN
were used depending on the purpose of data interpretation. Σ11 TEQPCN were used for the comparison of the “proportions” of the intake from food items or food groups to the total intake of PCNs. Otherwise, Σ20 TEQPCN were used for the estimated “values” of the intake of PCNs.
Based on the food consumption survey (KNHANES) conducted by KHIDI, the average daily consumption of 496 food items for overall average age group was 1505.17 g/day (KHIDI, 2019). With the absence of consumption data of pheasant meat, the daily food consumption of 57 selected food in this study was 658.5 g/day, which accounted for 44% of the total consumption. In addition, the considered food categories (agricultural products, fishery products, livestock products, and processed foods) cover 74% of the total. Daily food consumptions of 9 age groups (1–2, 3–5, 6–11, 12–18, 19–
29, 30–49, 50–64, over 65, and overall average) were listed in Table S5.
Figures 12 to 16 depict the contributions of food items to the total intake of Σ11 TEQPCN, the intake from agricultural products, fishery products, livestock products, and processed foods, respectively. Each figure consists of pi-charts for overall average and 8 age groups.
The results of earlier studies were referred for each food group. However, it is important to note that direct comparison was impossible due to the limited number of studies, difference of congeners, homologue groups, food items and categories, and based on whether TEQs are applied.
30
Figure 12. Distributions of dietary intake (pg-TEQ/kg bw/day) of Σ11 TEQPCN in selected food samples.
The contributions of eleven PCN congeners in each food item to the total intake are depicted in Figure 12. The intakes from oyster, webfoot octopus, beef, sesame oil, and soybean oil were zero, due to the influence of TEQ values. For the overall average group, the total intake of Σ11 TEQPCN from 57 food items was 0.392–0.823 pg-TEQ/day. Previous studies reported the total intake of tetra-CNs to octa-CN as 0.104 ng/kg bw/day in Spain (Martí-Cid et al., 2008), and the total intake of 26 congeners as 0.036 pg/kg bw/day in Latvia (Zacs et al., 2020).
The highest contribution to the total intake corresponded to pork (27–35%) for people between 6 and 49 years old, whereas rice made the biggest contribution (23–31%) for the youngest (1–5 years) and the oldest (≥ 50 years), due to the very high consumption of pork (12.67–75.37 g/day; mean 50.21 g/day) and rice (97.3–171.1 g/day; mean 145.9 g/day) among the Korean population. In spite of the high Σ11TEQPCN, the contributions of sailfin sandfish (2.7×10-5 pg-TEQ/kg bw/day), rockfish (8.9×10-5 pg- TEQ/kg bw/day), Spanish mackerel (4.4×10-5 pg-TEQ/kg bw/day), and salmon (7.5×10-5 pg-TEQ/kg bw/day) were relatively low due to the low consumption of these fish in Korea.
Pork 25%
Rice 22%
Anchovy 9%
Radish 5%
Duck meat 5%
Egg, 4%
Onion, 3%
Ramen, 3%
Rice 28%
Anchovy 17%
Pork Yogurt 12%
6%
Egg 5%
Milk 5%
Hairtail, 4%
Pork 27%
Rice Duck 24%
meat 6%
Anchovy 6%
Egg, 5%
Ramen, 4%
Milk, 3%
Pork 33%
Rice 19%
Anchovy 7%
Ramen 5%
Radish, 5%
Egg, 4%
Onion, 4%
Pork 29%
Rice 20%
Anchovy 8%
Duck meat 5%
Radish 5%
Egg, 4%
Onion, 3%
Rice 23%
Pork 19%
Anchovy 12%
Radish 7%
Egg, 4%
Duck meat 3%
Onion, 3%
Hairtail, 3%
Rice 31%
Anchovy Pork 13%
12%
Radish 7%
Duck meat 5%
Hairtail, 4%
Onion, 3%
Pork 35%
Rice Duck 21%
meat 7%
Ramen 6%
Egg, 4%
Anchovy, 3%
Rice 25%
Pork 17%
Anchovy 13%
Duck meat 8%
Yogurt 6%
Egg, 5%
1–2 3–5
6–11 12–18
30–49 65
19–29 50–64
Overall average
31
Figure 13. Distributions of dietary intake (pg-TEQ/kg bw/day) of Σ11 TEQPCN in agricultural products.
Figure 13 shows the contribution of Σ11 TEQPCN in each food item to the intake from nine agricultural products. The sum of the intake of Σ11 TEQPCN from these agricultural products ranged from 0.157 to 0.299 pg-TEQ/day. A previous study in Spain reported the intake of tetra-CNs to octa-CN was 0.006 ng/kg bw/day from vegetables, and 0.004 ng/kg bw/day from fruits (Martí-Cid et al., 2008).
For the overall average age, the highest intake of Σ11 TEQPCN from agricultural products corresponded to rice (63%), followed by radish (15%) and onion (9%), which is due to the high consumption of rice and onion, and the high TEQs of radish. This result was similar across most of the Korean population except for 1–2 years old, whose intake came from rice, radish and apple. Unlike radish and onion, the consumption of apple for 1–2 year-olds is not significantly different from that of overall average, hence apple is third place for 1–2 year-olds. The sum of the intake from these three items accounted for 82.5–
90.3% of the intake from 9 agricultural products.
Rice 63%
Radish 15%
Onion 9%
Rice 70%
Radish 10%
Apple 6%
Rice 69%
Radish 7%
Onion 6%
Rice 70%
Onion 8%
Radish 8%
Rice 69%
Radish 10%
Onion 9%
Rice 63%
Radish 16%
Onion 12%
Rice 61%
Radish 15%
Onion 11%
Rice 59%
Radish 18%
Onion 8%
Rice 66%
Radish 14%
Onion 6%
1–2 3–5
6–11 12–18
30–49 65
19–29 50–64
Overall average
32
Figure 14. Distributions of dietary intake (pg-TEQ/kg bw/day) of Σ11 TEQPCN in fishery products.
Figure 14 depicts the contributions of 28 fishery products to the intake of Σ11 TEQPCN. The total intake of Σ11 TEQPCN from fishery products was 0.077–0.191 pg-TEQ/day. The intakes from these products were 0.012 pg-TEQ/kg/day in Latvia (Zacs et al., 2020), 0.022–0.028 ng/kg bw/day in Spain (Llobet et al., 2007; Martí-Cid et al., 2008), and 0.44 pg-TEQ/day for tetra-CNs to octa-CN in Korea (Kim et al., 2018).
Anchovy significantly contributed (35–70%) to the dietary intakes from fishery products due to the wide use of anchovy-based broth in various dishes in Korea. Hairtail and mackerel were also responsible for high intakes of Σ11 TEQPCN due to the high TEQ of hairtail and high consumption of mackerel. These results match the results of a previous study on fisheries in Korea (Kim et al., 2018). The top three contributors accounted for 87.4–88.2 % of the intake from fisheries among young children (1–5 years old), and 56.9–67.8% in adults (19–49 years old). This means more items affected the intake from fisheries for adults.
Anchovy 46%
Hairtail 11%
Mackerel 7%
Small octopus 6%
Crab 6%
Anchovy 63%
Hairtail 16%
Mackerel 9%
Anchovy 70%
Mackerel 9%
Hairtail 8%
Anchovy 42%
Hairtail 17%
Mackerel 10%
Spanish mackerel
8%
Anchovy 35%
Crab Small 13%
octopus 11%
Hairtail 11%
Spanish mackerel
7%
Anchovy 43%
Hairtail Small 12%
octopus 8%
Squid, 6%
Mackerel 5%
Anchovy 42%
Crab Squid8%
7%
Hairtail 7%
Small octopus 7%
Mackerel 7%
Anchovy 48%
Hairtail 13%
Mackerel 8%
Crab 6%
Anchovy 53%
Hairtail 15%
Mackerel 8%
1–2 3–5
6–11 12–18
30–49 65
19–29 50–64
Overall average
33
Figure 15. Distributions of dietary intake (pg-TEQ/kg bw/day) of Σ11 TEQPCN in livestock products.
The contributions of seven livestock products to the intake of Σ11 TEQPCN are given in Figure 15. The total intake of Σ11 TEQPCN from livestock products was 0.076–0.368 pg-TEQ/day. According to the overall average group, the highest contribution corresponded to pork (75%), followed by duck meat (14%), and eggs (11%). The high intakes of pork and eggs were influenced by high consumption, 50.21 g/day and 29.53 g/day, respectively. By contrast, the high intake of duck meat was affected by its high TEQ, which was three times higher than that of pork. These items accounted for more than 99% of the total intake from livestock products regardless of the age of the consumer. Although other items, including beef and chicken meat, have high consumption, their contributions to the intake of PCNs were much lower, or even zero, due to their TEQ values. A previous study in Latvia reported the intakes from meat and meat products as 0.003 pg-TEQ/kg bw/day, and from eggs as 0.0002 pg-TEQ/kg bw/day for 26 PCN congeners (Zacs et al., 2020). The intakes of tetra-CNs to octa-CN from meat and meat products was 0.006 ng/kg bw/day in Spain (Martí-Cid et al., 2008).
Pork 75%
Duck meat 14%
Egg
11% Pork
62%
Egg 27%
Duck meat
11%
Pork 56%
Duck meat
27%
Egg 17%
Pork 71%
Duck meat
17%
Egg 12%
Pork 76%
Duck meat
16%
Egg 8%
Pork 85%
Egg 10%
Duck meat
5%
Pork 61%
Duck meat
25%
Egg 14%
Pork 76%
Duck meat
14%
Egg 10%
Pork 73%
Egg 14%
Duck meat
13%
1–2 3–5
6–11 12–18
30–49 65
19–29 50–64
Overall average
34
Figure 16. Distributions of dietary intake (pg-TEQ/kg bw/day) of Σ11 TEQPCN in processed foods.
Figure 16 shows the contributions of 13 processed foods to the intake of 11 PCN congeners. For the overall average age, the total intake of Σ11 TEQPCN from processed foods was 0.046–0.114 pg-TEQ/day, and the intake from ramen (31%) was the highest, followed by kimchi (18%), yogurt (18%), and milk (12%). Although the TEQ values of milk and kimchi were much lower than others, they were ranked top due to their large consumption. Unlike other food groups, the highest intake corresponded to different items according to age. The highest intake for young children (1–2 and 3–5 years old) came from yogurt (46 and 42%) and milk (38 and 32%), while the highest for people between 6 to 49 years old corresponded to ramen (28–41%). For people over 50 years old, kimchi accounted for 26–30% as the major contributor. Among the 13 food items, the four highest ranked items covered more than 72.9–
95.3% of the intake from processed foods.
Since the processed foods consumed by each country are different, there were few previous studies on the items used in this study. The intake from tetra-CNs to octa-CN was 0.005 ng/kg bw/day in dairy products and 0.008 ng/kg bw/day in oils and fats (Martí-Cid et al., 2008). A previous study on dairy products reported that the intake from tetra-CNs to octa-CN was 0.004 pg-TEQ/kg bw/day in Latvia (Zacs et al., 2020).
Ramen 31%
Kimchi Yogurt 18%
18%
Milk 12%
Yogurt 46%
Milk 38%
Ice cream
7% Yogurt
42%
Milk 32%
Ice cream
11%
Ramen 28%
Milk Yogurt 22%
17%
Ice cream
16%
Ramen 41%
Yogurt 14%
Milk 13%
Ice cream 11%
Ramen 40%
Kimchi 12%
Yogurt 11%
Milk 10%
Ice cream
10%
Ramen 34%
Kimchi 19%
Yogurt 14%
Milk 10%
Kimchi 26%
Ramen Yogurt 23%
22%
Milk 10%
Kimchi 30%
Yogurt 27%
Ramen 17%
Milk 11%
1–2 3–5
6–11 12–18
30–49 65
19–29 50–64
Overall average
35
Figure 17 illustrates the profiles of the estimated intake of Σ11 TEQPCN (pg-TEQ/kg bw/day) from four food groups according to age. Based on the overall average consumption, the contribution to the total intake of Σ11 TEQPCN was the highest from agricultural products (36%), followed by livestock products (34%), fishery products (20%) and processed food (10%). By contrast, in previous studies, fishery products usually were the highest contributor to the total intake of PCNs (Fernandes et al., 2011; Martí- Cid et al., 2008; Zacs et al., 2020). Among the 12 food groups, fish and seafood constituted approximately 40% of the total intake of PCN concentrations in Spain (Martí-Cid et al., 2008). Another study of the Latvian population also found fishery products as a major contributor, which made up 60%
of the total intake of Σ TEQPCN (Zacs et al., 2020). In addition, in a study on Irish foods, dairy products and fish were the major contributors, which constitute 37% each, due to large consumption of dairy products and the high concentrations found in fish (Fernandes et al., 2011). The difference between the results of this study and others was due to the influence of the larger consumption of agricultural products (182–343 g/day) than fisheries (14–43 g/day) or other food groups.
Figure 17. (a) Fractions and (b) distributions of dietary intakes (pg-TEQ/kg bw/day) of Σ11 TEQPCN for ages.
0 20 40 60 80 100
1-2 3-5 6-11 12-18 19-29 30-49 50-64 ≥ 65 Overal l
0.00 0.01 0.02 0.03 0.04
Fraction (%)Intake (pg-TEQ/kg bw/day)
(a) Fraction
(b) Intake
0
Agricultural Fishery Livestock Processed
36
The ratios of the contribution of food groups were different depending on the age. The 12–18 years old group has the lowest contributions of agricultural (31%) and fishery (9%) products, and the highest contribution of livestock products (46%). The younger or older than 12–18 years old group, the higher the contribution of agricultural and fishery products whereas the lower the contribution of livestock products. Hence, the highest contributions of agricultural and fishery products were observed in youngest (1–2 years old) and oldest (≥ 65 years old) groups. Likewise, the lowest contribution of livestock products corresponded to youngest and oldest groups (19–20%). Meanwhile, older groups tended to have lower contributions of processed foods.
The total intake of Σ20 TEQPCN in food according to age and gender are shown in Table 7 and Table 8.
For the Korean population except for 1–2 year olds, higher intakes were observed in male groups than in female groups. Among the sixteen age/gender groups, the highest intake corresponded to males aged 30–49 years (1.0288 pg-TEQ/day), and the lowest intake corresponded to males aged 1–2 years (0.3961 pg-TEQ/day). However, on a body weight basis, females aged 1–2 years showed the highest intake (0.0336 pg-TEQ/kg bw/day) and the oldest females showed the lowest (0.0097 pg-TEQ/kg bw/day).
This can be explained by the difference in average body weight of each age group.
Earlier studies showed similar results with higher intakes in younger groups. Higher exposure was observed in children (1.65 ng/kg bw/day) than in the older adults (0.54 ng/kg bw/day) in Spain, and the consumption per body weight influenced to the result (Domingo et al., 2003). Another study in UK reported the intake of 0.39 pg-TEQ/kg bw/day for adults and 0.98 pg-TEQ/kg bw/day for young children (4–6 years) (Fernandes et al., 2010).
The intakes of Σ20 TEQPCN were compared to TWIs of dioxin-like compounds based on the TEQ values.
The estimated intakes in this study were much lower than the TWIs proposed by MFDS (14 pg-TEQ/kg bw/week) and EFSA (2 pg-TEQ/kg bw/week) (EFSA, 2018; MFDS, 2017). However, in addition to the intake of PCNs, other dioxin-like contaminants present in food should be considered. Previous studies in several countries including Netherlands, Turkey, China, Sweden, Germany and Korea reported the concentrations of PCDD/Fs and DL-PCBs in food (Kilic et al., 2011; Schwarz et al., 2014; Shin et al., 2015; Song et al., 2011; Theelen et al., 1993; Törnkvist et al., 2011). Therefore, the total combined intake of TEQ values from PCNs, PCDD/Fs and DL-PCBs were calculated and compared to the TWIs in 3.4.2.
37 Table 7. Dietary daily intakes of Σ20 TEQPCN in selected food items in male groups.
Food categories (pg-TEQ/day)
Age groups
Overall 1–2 3–5 6–11 12–18 19–29 30–49 50–64 ≥ 65
Agricultural products 0.308 0.167 0.181 0.225 0.306 0.269 0.316 0.358 0.329
Fishery products 0.173 0.082 0.095 0.085 0.087 0.134 0.195 0.222 0.193
Livestock products 0.324 0.085 0.179 0.265 0.440 0.377 0.415 0.261 0.161
Processed foods 0.097 0.061 0.074 0.089 0.133 0.121 0.104 0.086 0.061
Total intake
(pg-TEQ/day) 0.901 0.396 0.530 0.663 0.966 0.901 1.029 0.926 0.743
Body weight (kg) 66.7 12.1 17.6 34.3 64.9 74.8 76.3 70.1 66.2
Food categories (pg-TEQ/kg bw/day)
Age groups
Overall 1–2 3–5 6–11 12–18 19–29 30–49 50–64 ≥ 65
Agricultural products 4.6×10-3 1.4×10-2 1.0×10-2 6.6×10-3 4.7×10-3 3.6×10-3 4.1×10-3 5.1×10-3 5.0×10-3 Fishery products 2.6×10-3 6.8×10-3 5.4×10-3 2.5×10-3 1.3×10-3 1.8×10-3 2.6×10-3 3.2×10-3 2.9×10-3 Livestock products 4.9×10-3 7.1×10-3 1.0×10-2 7.7×10-3 6.8×10-3 5.0×10-3 5.4×10-3 3.7×10-3 2.4×10-3 Processed foods 1.5×10-3 5.1×10-3 4.2×10-3 2.6×10-3 2.1×10-3 1.6×10-3 1.4×10-3 1.2×10-3 9.2×10-4
Total intake
(pg-TEQ/kg bw/day) 1.4×10-2 3.3×10-2 3.0×10-2 1.9×10-2 1.5×10-2 1.2×10-2 1.3×10-2 1.3×10-2 1.1×10-2
38 Table 8. Dietary daily intakes of Σ20 TEQPCN in selected food items in female groups.
Food categories (pg-TEQ/day)
Age groups
Overall 1–2 3–5 6–11 12–18 19–29 30–49 50–64 ≥ 65
Agricultural products 0.231 0.157 0.160 0.187 0.196 0.187 0.228 0.258 0.282
Fishery products 0.129 0.125 0.084 0.081 0.067 0.113 0.139 0.163 0.124
Livestock products 0.170 0.067 0.100 0.192 0.292 0.183 0.203 0.143 0.097
Processed foods 0.071 0.054 0.073 0.088 0.110 0.084 0.071 0.070 0.043
Total intake
(pg-TEQ/day) 0.601 0.403 0.417 0.548 0.664 0.567 0.640 0.635 0.547
Body weight (kg) 55.0 12.0 17.5 32.6 54.3 57.5 59.3 59.0 56.5
Food categories (pg-TEQ/kg bw/day)
Age groups
Overall 1–2 3–5 6–11 12–18 19–29 30–49 50–64 ≥ 65
Agricultural products 4.2×10-3 1.3×10-2 9.1×10-3 5.7×10-3 3.6×10-3 3.3×10-3 3.8×10-3 4.4×10-3 5.0×10-3 Fishery products 2.3×10-3 1.0×10-2 4.8×10-3 2.5×10-3 1.2×10-3 2.0×10-3 2.3×10-3 2.8×10-3 2.2×10-3 Livestock products 3.1×10-3 5.6×10-3 5.7×10-3 5.9×10-3 5.4×10-3 3.2×10-3 3.4×10-3 2.4×10-3 1.7×10-3 Processed foods 1.3×10-3 4.5×10-3 4.2×10-3 2.7×10-3 2.0×10-3 1.5×10-3 1.2×10-3 1.2×10-3 7.7×10-4
Total intake
(pg-TEQ/kg bw/day) 1.1×10-2 3.4×10-2 2.4×10-2 1.7×10-2 1.2×10-2 9.9×10-3 1.1×10-2 1.1×10-2 9.7×10-3
39