Background: Mercury, particularly in its methylmercury form, significantly affects neu-

Overview

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Key numbers

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7.1% exceed the single intake limit, while up to 1.9% exceed the JECFA’s provisional tol-
erable weekly intake (PTWI) and 0.6% exceed the MFDS’s PTWI, suggesting consider-
children of Minamata, due to prenatal exposure.4,5 Al- through this region, which is said to supply 50% of the
of foods containing mercury. Ingested methylmercury is higher blood mercury levels (>7.0 µg/L) than the aver-
buk-do, in which shark meat consumption is a tradition 6 months in the past year (Table 1).
Table 1. General characteristics of the study subjects
in each district, with a target error of ±3%, and allocated Yes 69 1.9 (0.3)
95% CIs. A CI that did not include zero was considered
shark meat consumption. The estimated numbers, 95% The prevalence of shark meat consumption among
ages of the population in each category were calculated. buk-do was 22.5%, and when calculated by region, the
The number of intakes was converted to the number prevalences in Yeongcheon-si (54.6%), Gyeongju-si
months) for better comparability, and the annual intake Uisung-gun (38.4%), Gyeongsan-si (36.8%), and
(annual intake × serving size) was calculated for each Cheongsong-gun (29.8%) were higher than the overall
individual and used for statistical analysis. The mean, prevalence in Gyeongsangbuk-do (Fig. 1). The highest
95% CIs, and maximum values of the annual intake consumption rates were found in the central and south-
exposure over a year, the annual intake was calculat- buk-do had as a whole (22.0% and 13.1%, respectively).
The prevalence of shark meat consumption among more than this amount was 28.1% (n = 291) of all young
was 18.6% (n = 14) of pregnant women, 23.1% (n = 49) had given birth in the past year, and 11.5% (n = 4) of
of those who had given birth within the past year, and those who had breastfed in the past year (Table 2).
26.5% (n = 23) of those who had breastfed within the The number of servings were up to 156 per year (mean:
past year. 3.14; 95% CI: 2.92–3.35) among all young and mid-
size greater than or equal to the size of their entire palm seven per year (mean: 2.59; 95% CI: 2.18–3.01) among
were 7.1% (n = 61) of those of young and middle-aged women who had given birth within the past year; and up
(n = 4) of those who had given birth in the past year, and women who had breastfed within the past year. The
7.4% (n = 3) of those who had breastfed in the past year. mean annual total intake for all young and middle-aged
women (95% CI: 6,762–13,027) aged 19–55 in the overall mean annual intake for pregnant women was 66 g, with
sumed shark meat in excess of the recommended intake. take was 107 g, with a maximum of 500 g (Table 3).
Fig. 2. (A) Geographical distribution of estimated consumption rate (%) in Gyeongsangbuk-do. Consumption rate (%) is defined as the propor-
Table 3. Mean and maximum annual consumption in young and middle-aged women
estimation of 176 (n = 2 (95% CI: –133 to 486)) young PTWI established by regulatory authorities. Based on
JECFA threshold (1.6 µg/kg/week)23 and 20 (n = 1 (95% population estimates revealed statistically significant
(8.93 µg/g),22 it was estimated that 2,645 (n = 18 (95% CI: mercury concentration in shark meat was 8.93 µg/g, the
1,053–4,237)) and 845 (n = 6 (95% CI: 46–1,645)) people estimated population exceeding the PTWI was 845 (95%
this study was 622,123 (95% CI: 601,875–642,371), with
a need for more proactive advisory measures against mercury level should be 1.5 μg/L. However, the average
of updating control standards for mercury content in 3.11 µg/L (95% CI: 2.36–2.65 µg/L),31 which means that
μg/L, Cheongsong 6.85 μg/L, Yeongdeok 6.33 μg/L, Po- study include the fact that the exact blood mercury lev-
L, Andong 5.55 μg/L, Gunwi 5.47 μg/L, Cheongdo 5.38 foods that may affect blood mercury levels were not
μg/L, and Gyeongsan 4.87 μg/L (Gyeongsangbuk-do examined. In addition, recall bias in questionnaire re-
overall 4 μg/L).20 Spearman’s correlation analysis was sponses to items about shark meat consumption char-
blood mercury levels by 0.02 μg/L,21 consuming shark monitoring and guidance. Community-level interven-
levels by 2 μg/L. The reference value for maternal blood Continuous monitoring of methylmercury levels in

Methods (brief)

Korea breastfeeding status. The Complex Sample Analysis was used to determine the preva-
1999). The survey sampled from a comprehensive list of
and Transport. The sample size was then stratified by Age > 55 years 7,881 55.2 (0.7)
an average sample size of 900 people per health center Pregnancy status
as sample points by cluster sampling. The raw survey Total 231 100
sample that includes stratification variables, cluster for analysis.
plex sample statistical analysis to reflect this. Ethics statement
tradition of turn-taking and rituals.17,18 These character- Also, given that the community health survey sample
istics may explain the difference in consumption rates used in this study was a reliable sample with stratifi-

Implications

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised