Lin 2021 - Taiwan seafood mercury total diet study

Lin, Nan, and Ling measured total mercury in 140 Taiwan seafood samples and compared raw and steam-cooked preparations. The study then estimated methylmercury exposure using literature-derived MeHg/THg ratios for seafood families. Measured occurrence values are total mercury; methylmercury values in this paper are converted estimates used for risk assessment, not directly measured MeHg concentrations.

Key numbers

The total diet study classified 140 seafood samples into seven categories and 82 species: pelagic fish n = 17, inshore fish n = 35, other farmed fish n = 47, shellfish n = 9, cephalopods n = 10, crustaceans n = 16, and algae n = 6. Each sample was analyzed raw and steam-cooked.

THg was measured by ICP-MS. The mean recovery of THg in certified reference material was 94.85%, and the detection limit for THg analysis was 0.02 mg/kg.

Table 4 reports total mercury (THg) concentrations in mg/kg:

Table 4 footnotes define ND as 0.02 mg/kg for uncooked/raw seafood and 0.01 mg/kg for cooked/steamed seafood.

The Results text reports raw THg ranges of 0.03-3.16 mg/kg in pelagic fish, ND-0.78 mg/kg in inshore fish, ND-0.35 mg/kg in other farmed fish, ND-0.06 mg/kg in shellfish, ND-0.05 mg/kg in cephalopods, ND-0.14 mg/kg in crustaceans, and ND in algae. Cooked THg ranges were 0.05-4.59 mg/kg in pelagic fish, ND-1.39 mg/kg in inshore fish, ND-0.47 mg/kg in other farmed fish, ND-0.05 mg/kg in shellfish, 0.02-0.11 mg/kg in cephalopods, ND-0.23 mg/kg in crustaceans, and ND-0.01 mg/kg in algae.

The paper estimated MeHg from THg using literature MeHg/THg ratios. The ratios used were 73-100% for pelagic fish, 83.6-100% for inshore fish, 75-100% for other farmed fish, 35-82% for shellfish, 72.8-92% for cephalopods, and 80% for crustaceans and algae.

Estimated raw MeHg ranges were 0.025-2.307 mg/kg in pelagic fish, ND-0.760 mg/kg in inshore fish, ND-0.329 mg/kg in other farmed fish, ND-0.048 mg/kg in shellfish, ND-0.036 mg/kg in cephalopods, ND-0.112 mg/kg in crustaceans, and ND-0.024 mg/kg in algae. Estimated cooked MeHg ranges were 0.042-3.351 mg/kg in pelagic fish, ND-1.354 mg/kg in inshore fish, ND-0.442 mg/kg in other farmed fish, ND-0.0400 mg/kg in shellfish, 0.016-0.080 mg/kg in cephalopods, ND-0.184 mg/kg in crustaceans, and ND-0.008 mg/kg in algae.

Raw THg detection rates were pelagic fish 100%, inshore fish 91%, other farmed fish 62%, shellfish 33%, cephalopods 50%, crustaceans 69%, and algae 17%. After cooking, detection rates increased for inshore fish (97%), other farmed fish (89%), shellfish (67%), cephalopods (100%), and crustaceans (88%).

The paper states that overall Hg concentrations were higher in cooked samples than in raw samples, increasing by 50% to 80%, and attributes the increase mainly to water loss during cooking.

For health-risk modeling, the MeHg reference dose was 1.6 µg/kg BW/week as PTWI. The abstract states that, in a 75th percentile scenario, hazard indices for children aged 1 to 3 years and 4 to 6 years were higher than 100% of PTWI.

Consumption advisories in Table 5 use 35 g servings. The abstract reports weekly advisories for childbearing women of 35 g/week of pelagic fish and 245 g/week of inshore fish, based on MeHg risk results and EPA/DHA composition.

Methods (brief)

Seafood categories were defined from Taiwan sanitation standards for aquatic animals and algae foods, domestic sales volume, import/export statistics, and Taiwan dietary survey consumption rates. Samples were purchased from fishing ports, traditional wet markets, afternoon markets, supermarkets, and discount stores across Taiwan. Edible parts were homogenized; each sample was analyzed raw and after steam cooking for 10 min. THg was measured by ICP-MS. MeHg was not directly measured; the paper estimated MeHg by applying literature-derived MeHg/THg ratios to steam-cooked THg values for risk assessment.

Implications

This source contributes Taiwan total-diet-study evidence for seafood total mercury, including raw and cooked bases. It is useful for fish, shellfish, crustacean, cephalopod, and algae/seaweed routing, but the benchmark pool should keep the measured THg table separate from the converted MeHg risk estimates. The cooked THg values are especially relevant for as-consumed exposure context because the paper shows cooked concentrations higher than raw values.

Verification notes

• PDF text extracted with pdftotext -layout; title page, methods, Tables 1-4, Results sections, risk discussion, Table 5 text, and appendices were readable.
• DOI 10.3390/ijerph182212227, raw handle MFK_ijerph-18-12227, and cite-key checks found no existing source page before creation.
• Table 1 sample counts, Table 4 THg values, MeHg/THg conversion ranges, MeHg estimated ranges, detection rates, and method recovery/LOD values were checked against extracted text. Units are preserved as mg/kg, µg/kg BW/week, and g/week; no conversion was performed.
• Speciation: THg was measured directly; MeHg concentrations were estimated from literature MeHg/THg ratios and are not direct MeHg measurements.
• Brand firewall: no sampled seafood product brands were reported.
• Missing closed-vocabulary slugs: cephalopod and crustacean product slugs are not present in the taxonomy snapshot, so those categories are documented in the body without invented frontmatter product slugs.

Page history

The five most recent substantive edits to this page. 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.