Aguilar-Miranda et al. 2024 - Total mercury in canned tuna sold in Quito, Ecuador

Aguilar-Miranda et al. measured total mercury (tHg) in 60 cans of tuna in water purchased from supermarkets in the Metropolitan District of Quito, Ecuador. The study sampled three anonymized coded product groups, 20 cans per group, between March 2022 and March 2023. Mercury was quantified by cold-vapor atomic fluorescence spectrometry after freeze-drying and microwave-assisted acid digestion. The authors measured tHg only; they did not speciate methylmercury (MeHg) or inorganic mercury. For the exposure assessment, they followed the US EPA fish-advisory convention of treating measured tHg as MeHg.

The overall tHg range was 0.02-1.98 mg/kg wet weight. One sample in the intermediate-price coded group reached 1.98 mg/kg and another sample in the same coded group reached 1.0 mg/kg. The authors state that 96.7% of samples were below the national and international threshold limits they cite. The source uses anonymized group codes rather than public brand names; this page preserves those codes only as non-identifying sample strata and does not name or rank sampled manufacturers.

Key numbers

• Sample design: 60 cans total; three coded product groups; 20 cans per group; samples purchased from Quito supermarkets from March 2022 through March 2023.
• Coded group A: mean tHg 0.14 +/- 0.11 mg/kg w.w.; range 0.02-0.37 mg/kg; Table 1 combined 2022-2023 row.
• Coded group B: mean tHg 0.41 +/- 0.42 mg/kg w.w.; range 0.12-1.98 mg/kg; Table 1 combined 2022-2023 row.
• Coded group C: mean tHg 0.25 +/- 0.22 mg/kg w.w.; range 0.04-0.78 mg/kg; Table 1 combined 2022-2023 row.
• Year-specific Table 1 rows:
  • 2022: A 0.17 +/- 0.12 (0.04-0.37), B 0.43 +/- 0.55 (0.12-1.98), C 0.25 +/- 0.20 (0.06-0.78) mg/kg w.w.
  • 2023: A 0.11 +/- 0.11 (0.02-0.37), B 0.39 +/- 0.25 (0.20-1.00), C 0.24 +/- 0.24 (0.04-0.69) mg/kg w.w.
• Compliance/exceedance statement: 96.7% of analyzed samples were below the cited tHg threshold limits; one coded-group-B batch at 1.98 mg/kg exceeded the EU 2023, FAO 2019, and Ecuador NTE INEN 184:2013 comparators cited by the paper; another coded-group-B sample was at 1.0 mg/kg.
• Paper-cited maximum levels: EU 2023/915 / EU mercury fish tier for tuna, 1.0 mg/kg tHg; Ecuador NTE INEN 184:2013 for canned tuna, 1.0 mg/kg tHg; FAO/Codex comparator as cited by the paper, 1.2 mg/kg.
• FDA/EPA reference value used by the authors: 0.46 mg/kg tHg for fish eaten at one serving per week; 20% of coded-group-B samples and 15% of coded-group-C samples exceeded this reference value.
• Table 4 exposure/risk values based on mean tHg treated as MeHg:
  • Children: Ex 5.40 x 10^-5, Rx 0.5, weekly intake 169 g for coded group A; Ex 1.61 x 10^-4, Rx 1.6, weekly intake 57 g for coded group B; Ex 9.68 x 10^-5, Rx 0.97, weekly intake 94 g for coded group C.
  • Adults: Ex 2.24 x 10^-5, Rx 0.2, weekly intake 817 g for coded group A; Ex 6.68 x 10^-5, Rx 0.7, weekly intake 274 g for coded group B; Ex 4.01 x 10^-5, Rx 0.40, weekly intake 456 g for coded group C.
• Maximum-concentration weekly-intake calculations in the text: adults/children 306 g/63 g for coded group A, 57 g/12 g for coded group B, and 144 g/30 g for coded group C.
• Health-risk parameters: MeHg RfD 1 x 10^-4 mg/kg bw/day; PTWI for MeHg 1.6 ug/kg human body weight/week; body weight 70 kg for adults and 14.5-15 kg for children, with 14.5 kg used in Table 4.
• Literature comparator range in the source discussion: canned tuna tHg in Latin American studies ranged from 0.005 to 1.4725 mg/kg.
• Source-cited biological context: the introduction states that approximately greater than 89% of tHg in tuna muscle is methylated according to cited literature, but this study did not independently measure MeHg.

Methods (brief)

Sixty cans of tuna in water were purchased from supermarkets in Quito, Ecuador, from March 2022 to March 2023. Each can contained an 80 g sample. The water was drained, tuna meat was homogenized with a stainless-steel blender, and about 20 g from each can was freeze-dried for 48 h at -50 deg C and 0.150 hPa. Results were reported as wet weight.

For digestion, 0.1 g dried sample was treated with 1 mL HNO3, 1 mL H2O2, and 1 mL HClO4 in high-pressure PTFE vessels and digested in a CEM MARS 6 microwave at 210 deg C, 20 min ramp, 15 min hold, 1400 W, and 800 psi. THg was quantified with a Mercur Plus cold-vapor atomic fluorescence spectrometer coupled to a cold-vapor generator (Analytik Jena). Calibration covered 0.5-5 ug/L from a Hg+2 stock solution. Instrumental LOD and LOQ were 0.10 ug/L and 0.34 ug/L. The study used IAEA-436A tuna fish flesh homogenate as certified reference material; mean recovery was 103% +/- 5% (96-110%). Sample fortification recoveries were 99% +/- 2% at 1 ug/L and 91.0% +/- 5% at 4 ug/L. Digestions and measurements were performed in duplicate.

The authors calculated descriptive statistics in Excel 2016. They used Kruskal-Wallis and pairwise Wilcoxon tests in R to compare the three coded groups and Chebyshev’s theorem to evaluate dispersion. Human-health risk calculations used the US EPA fish-advisory assumption that tHg in fish can be treated as MeHg for risk calculations when MeHg is not measured.

Speciation and interpretation notes

• The measured analyte is total mercury (tHg). MeHg was not speciated analytically.
• Risk calculations are based on tHg-as-MeHg substitution. This is a conservative exposure-assessment convention, not a measured MeHg result.
• The source contains an internal comparator inconsistency: most regulatory text, Table 1 notes, and the conclusion use 1.0 mg/kg for Ecuador NTE INEN 184:2013 / EU tuna comparators, but one paragraph states that coded group B was closest to an “Ecuadorian limit of 0.5 mg/kg.” This page treats the 1.0 mg/kg value as the paper’s operative Ecuador canned-tuna comparator and flags the 0.5 mg/kg sentence as source-internal inconsistency rather than silently harmonizing it.
• The paper filename in the manual-fetch folder says “Spain,” but the paper itself is about canned tuna in water sold in Quito, Ecuador. Spain appears only as a comparator country in Table 3.

Implications for wiki use

This page contributes occurrence and exposure-assessment evidence for canned tuna tHg in Ecuadorian retail samples. The finding most relevant for downstream standards work is the wide within-category spread: mean group values were below 0.5 mg/kg, but the maximum value reached 1.98 mg/kg. The source is not a species-resolved dataset, because two of the three coded groups did not disclose tuna species on the label; the one labeled group was Thunnus albacares. Use this page for canned-tuna occurrence context, not as evidence that a named manufacturer or public brand is safer or riskier than another.

Wiki pages this source may touch

• canned-tuna
• fish
• seafood
• canned-fish
• seafood
• mercury
• mercury-total
• mercury-methyl
• eu-reg-2022-617-mercury-fish
• eu2023-contaminants-maximum-levels
• ecuador-nte-inen-184-2013-canned-tuna
• fda-cpg-540-600-methylmercury-fish
• epa-iris-methylmercury-rfd
• jecfa-methylmercury-ptwi

Sources

• Aguilar-Miranda A, Fernández L, Yánez-Jácome GS, Alcoser-Pinto B, Zambrano H, Paz-Suconota F, Espinoza-Montero P. 2024. “Total mercury exposure through canned tuna in water sold in Quito, Ecuador.” Scientific Reports 14:27951. DOI: 10.1038/s41598-024-79430-y.
• Manual-fetch PDF: raw/Manual Fetch Kimi /04_Meat_Poultry_Seafood/04_Meat_Poultry_Seafood/P0163_Total mercury exposure through canned tuna in water sold in Spain.pdf (SHA-256 3404846dfe53a1a37c22262870abee4eac23d012c1937e47e7fd62de51e3e73f).

Verification notes

• 2026-05-18 Codex merge-enhance: DOI match to the pre-existing aguilar-miranda2024-thg-canned-tuna-ecuador source page. Corrected raw_handle from the generic manual-fetch-kimi, restored the full manual-fetch PDF path, added the PDF SHA-256, replaced narrow/non-common matrix terms with broad fish, added exact access URL, expanded seafood/canned-fish routing, replaced invalid regulations/eu-2023-915 with existing EU mercury/current-framework slugs, and added the Ecuador NTE INEN 184:2013 regulation target.
• 2026-05-18 Codex merge-enhance: tightened strict Part 12 brand-firewall language. The source anonymizes sampled products as coded groups A, B, and C; this page keeps only those non-identifying codes needed to preserve Table 1/Table 4 numerical fidelity and does not name sampled manufacturers or present public brand rankings.
• 2026-05-18 Codex merge-enhance: corrected earlier page wording that said “one lot reached 1.98 +/- 0.42 mg/kg.” The source reports 1.98 mg/kg as the maximum value in the range for coded group B; 0.42 is the combined-row SD for that group, not the uncertainty on the maximum sample.

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.