Bartels et al. 2023 — Heavy metals in canned fish, Cape Coast market, Ghana

This study measured lead (Pb), zinc (Zn), iron (Fe), tin (Sn), manganese (Mn), and total mercury (tHg) in ten commercially available canned fish products from Cape Coast market in Ghana’s Central Region. Products covered three species groups: mackerel (n=4 products), sardines (n=4 products), and tuna (n=2 products). The paper compared Pb, Sn, and tHg against source-cited EU Regulation No. 1881/2006 values and reported all analyte means below the comparator levels. The dataset is most useful for Pb, Sn, and tHg values across three commercially important canned fish species in a West African retail context.

Key numbers

All values are source-reported in µg/g for homogenized canned fish contents; the paper does not state a separate wet-weight/dry-weight conversion. One µg/g is equivalent to one mg/kg and 1,000 µg/kg on the source-reported mass basis.

Lead (Pb): source-cited EC 1881/2006 comparator = 0.3 µg/g for fish

• Mackerel: mean 0.142 ± 0.017 µg/g (142 ppb)
• Sardine: mean 0.122 ± 0.034 µg/g (122 ppb)
• Tuna: mean 0.141 ± 0.006 µg/g (141 ppb)
• All three below EU limit of 0.3 µg/g (300 ppb); no significant difference across species types (ANOVA p=0.305)

Tin (Sn): source-cited EC 1881/2006 comparator = 200 µg/g for canned foods other than beverages

• Mackerel: mean 16.550 ± 3.700 µg/g (16,550 ppb)
• Sardine: mean 14.482 ± 10.202 µg/g (14,482 ppb)
• Tuna: mean 16.024 ± 0.195 µg/g (16,024 ppb)
• All values well below the 200 µg/g comparator; significant differences across species (ANOVA p=0.004)

Total mercury (tHg): source-cited EC 1881/2006 comparator = 0.5 µg/g for fishery products/default fish muscle

• Mackerel: mean 0.126 ± 0.017 µg/g (126 ppb)
• Sardine: mean 0.132 ± 0.012 µg/g (132 ppb)
• Tuna: mean 0.263 ± 0.006 µg/g (263 ppb)
• All below EU 0.5 µg/g limit; tuna highest mean; no significant difference across species (ANOVA p=0.990)
• Note: tHg reported; MeHg fraction not speciated in this study

Zinc (Zn): source table lists 100 µg/g as a recommended comparator; the EC 1881/2006 attribution for Zn appears questionable (see Verification notes); significant variation across species (ANOVA p=0.024)

• Mackerel: mean 0.137 ± 0.048 µg/g; Sardine: 0.140 ± 0.039 µg/g; Tuna: 0.178 ± 0.022 µg/g

Iron (Fe): Significant variation (ANOVA p<0.001)

• Mackerel: mean 7.279 ± 6.832 µg/g; Sardine: 13.261 ± 9.945 µg/g; Tuna: 12.115 ± 1.985 µg/g

Manganese (Mn): No significant variation (ANOVA p=0.664)

• Mackerel: mean 0.017 ± 0.014 µg/g; Sardine: 0.024 ± 0.014 µg/g; Tuna: 0.022 ± 0.004 µg/g

Methods (brief)

Ten canned fish samples; 2 ± 0.001 g representative homogenized subsamples per product. tHg determined by Cold Vapor AAS using a Direct Mercury Analyzer. Pb, Sn, Zn, Mn, Fe determined by Flame AAS (UNICAM 969). Detection limits: Pb 0.010 µg/mL, Zn 0.002 µg/mL, Mn 0.002 µg/mL, Fe 0.005 µg/mL, Hg 0.001 µg/mL; no Sn detection limit is stated. Certified reference materials used for validation; method blanks performed. One-way ANOVA for species comparisons. Key limitation: n=10 products is small; sample duplication but no per-product replication reported; tHg not speciated to MeHg.

Implications

Certification: The source contributes occurrence data for canned fish products in a Ghanaian retail market: Pb species-group means of 122–142 ppb, Sn means of 14,482–16,550 ppb, and tHg means of 126–263 ppb. The tHg data capture total mercury; the paper did not measure MeHg. Tuna had the highest mean tHg in this small sample set.

Courses: Useful case for teaching species-level differences in Hg (tuna > sardine/mackerel in this dataset) and the distinction between tHg occurrence data and MeHg-specific exposure assessment.

App: For canned fish as a product class in Ghana/West Africa market context: Pb ~120–140 ppb, tHg ~130–263 ppb with tuna at upper range. Sn ~14,000–16,500 ppb (canning-vessel contribution, not from fish biology).

Wiki pages this source may touch

• seafood
• fish
• tinned-fish
• canned-tuna
• canned-fish
• seafood
• mercury-total
• lead
• tin
• zinc
• iron
• manganese
• eu-1881-2006-contaminants-superseded

Verification notes

• 2026-05-18 Codex merge-enhance: matched DOI/raw path to P0157, added full MFK raw handle/path and SHA-256 provenance, expanded metals: to include all six measured analytes, replaced the invalid ingredients/canned-fish link with existing fish/seafood/tinned-fish/canned-tuna ingredient slugs, and added [[products/seafood]] as broad product context.
• Existing cite key benjamin2023-canned-fish-ghana was retained for stable backlinks, but the page heading and author field now follow the PDF’s printed author order: Bartels Benjamin; Apaah Brakye Kenneth; Gadzekpo Victor Patrick Yao.
• Strict Part 12 brand-firewall cleanup: the source names the sampled products, but this page aggregates by fish type and omits all sampled-product brand names.
• Source Table 1 lists a Zn recommended limit of 100 µg/g under the “EU Reg. No 1881/2006” row. That value is reported above as a source-cited comparator, but the attribution appears questionable because EC 1881/2006 sets maximum levels for contaminants such as Pb, Cd, Hg, iAs, and Sn, not a fish-specific Zn maximum level.
• The paper’s Conclusion says “three mackerel” and “three tuna” samples, but the Abstract, Methods, and Table 1 grouping indicate 4 mackerel, 4 sardine, and 2 tuna products; this page follows the internally consistent Abstract/Methods design.
• The source reports Hg as mercury by cold-vapor AAS/direct mercury analyzer. It does not speciate methylmercury.

Page history

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