Dinesh Kumar et al. 2025 - Heavy metals in commercially important fish

Dinesh Kumar and colleagues compared heavy-metal concentrations across four organs (muscle, liver, intestine, gills) in three commercially important fish species landed at Ennore fishing port, Chennai (Bay of Bengal, India): Indian Oil Sardine (Sardinella longiceps, planktivorous), Indian Mackerel (Rastrelliger kanagurta, planktivorous), and Red Snapper (Lutjanus campechanus, carnivorous predator). The study is routeable for marine-fish occurrence context across both non-predatory and predatory product categories. The paper emphasizes organ-specific variation, so edible-muscle values must be separated from non-edible organ values during downstream extraction.

Key numbers

All concentrations are reported on a dry-weight basis in ppm (mg/kg dry tissue); the digestion procedure used 1 g of dried tissue.
Metals quantified (11): Cu, Cr, Al, Zn, Co, Hg, Pb, Ni, Fe, Cd, Mn, by inductively coupled plasma mass spectrometry.
Overall mean concentration ranking (Supplementary Table S1): Fe 525.23 ppm > Al 275.57 ppm > Zn 29.12 ppm > Mn 5.87 ppm > Cu 3.92 ppm > Cr 1.49 ppm > Ni 0.99 ppm > Co 0.25 ppm.
Fe ranged 4.05–4717.2 ppm and Al ranged 0.52–2663.81 ppm across organs.
Cd and Pb were often below the limit of quantification (BLQ). BLQ frequencies: Co 49/60 samples, Pb 34/60, Cd 32/60. Maximum observed concentrations: Cd 1.19 ppm, Pb 2.95 ppm.
Mean concentrations in muscle tissue (edible part): Cd 0.047 ± 0.05 ppm, Pb 0.084 ± 0.04 ppm (both dry weight).
Hg was consistently BLQ across all sampled tissues; the paper measured total Hg by ICP-MS and did not perform mercury speciation.
The authors compared muscle-tissue Cd and Pb means against WHO/FAO/Codex Alimentarius (2024) maxima of Pb 0.3 mg/kg, Cd 0.05–0.1 mg/kg, and Hg 0.5 mg/kg for methylmercury in fish.
Interspecies pattern: Snapper accumulated higher concentrations of most metals; Sardine carried elevated Fe, Al, and Zn; Mackerel showed the lowest levels.
Organ-level pattern: muscle consistently had the lowest values; liver was associated with Pb and Cu; intestine accumulated Fe, Al, Cr, and Ni; gills reflected waterborne exposure.

Methods (brief)

15 fish per species × 4 organs (muscle, liver, intestine, gills) = 60 organ samples. Tissues were dissected with sterile tools, stored at -20 °C, and 1 g of dried tissue digested at 140 °C with 5 mL concentrated nitric acid (Suprapur, Merck) in an Anton Paar microwave digestion system. Trace-element concentrations were quantified by ICP-MS (Agilent 7500). Analytical accuracy was validated against NIST CRM QC3163 (seawater). Results are total element concentrations in ppm on a dry-weight basis. The source measured total Hg by ICP-MS (consistently BLQ) and did not perform mercury speciation; report any downstream Hg routing as tHg, not MeHg.

Implications

Certification: Supports seafood metals context, but any benchmark extraction must isolate edible tissue from non-edible organs.

Courses: Useful for explaining why whole-organism or organ values cannot be silently pooled with fillet values.

App: Can inform seafood context if species and edible portion are retained.

Wiki pages this source may touch

Verification notes

The paper reports total-element values on a dry-weight basis (1 g dried tissue digested). Downstream extraction must preserve tissue type, retain the dry-weight basis flag, and route Snapper rows to predatory product pages and Sardine/Mackerel rows to non-predatory product pages. Organ means cannot be silently pooled with fillet (muscle) means.

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.

Commit	Date	Description
ae6c129	2026-07-01	feat(auth): large login + role-based signup screens (design, burgundy)

Comparative evaluation of heavy metal concentration in three commercially important fish: insights from organ-specific and interspecies variability