Dogruyol et al. 2024 — Toxic trace elements and Se in farmed Mediterranean mussels, Türkiye and Bulgaria
Dogruyol et al. measured selenium, cadmium, mercury, and lead in farmed Mediterranean mussels (Mytilus galloprovincialis) collected seasonally from four aquaculture farms — three on Turkish coasts (M1, M2, M3) and one in Bulgaria (M4). Analysis was by ICP-MS (Perkin Elmer NexION 1000) following microwave acid digestion (AOAC 999.10). CRM ERM-CE278k recoveries were 99–113%. All Hg is total mercury; the authors assumed 80% MeHg fraction for risk assessment following EFSA guidance, but no direct MeHg speciation was performed. All reported metals (Cd, Hg, Pb) were below EU and Codex maximum limits at the annual farm-mean level. The exception was a single spring sample from M2 (Pb 0.372 µg/g), which marginally exceeded the Codex recommended limit of 0.30 µg/g for mollusks. THQ and TTHQ values for Se, Cd, and MeHg were all below 1 for both Turkish and Bulgarian consumer consumption patterns; MOE-SBP and MOE-NE for Pb were well above 10. Se health benefit values (HBVSe 10.1–37.3) indicated that Se in mussels substantially outweighed any MeHg-associated risk.
Key numbers
All concentrations in µg/g wet weight (mean ± SD, n=3 per season per farm). Annual means shown below; full seasonal data in Table 3 of the source.
Annual mean concentrations by farm:
| Metal | M1 (TR) | M2 (TR) | M3 (TR) | M4 (BG) | EU/Codex limit |
|---|---|---|---|---|---|
| Se (µg/g) | 1.957 | 1.804 | 1.536 | 1.305 | — |
| Cd (µg/g) | 0.115 | 0.163 | 0.210 | 0.323 | 2 µg/g (EC) |
| tHg (µg/g) | 0.117 | 0.026 | 0.022 | 0.019 | 0.50 µg/g (EC) |
| Pb (µg/g) | 0.096–0.196 (seasonal) | 0.091–0.372 (seasonal) | 0.036–0.152 (seasonal) | 0.058–0.152 (seasonal) | 0.30 µg/g (Codex) |
Pb spring M2 exceedance: 0.372 µg/g (above Codex 0.30 µg/g). All Cd values below EU MRL 2 µg/g. All tHg values well below EU limit 0.50 µg/g.
LOD: Se 0.100 µg/kg, Cd 0.015 µg/kg, Hg 0.025 µg/kg, Pb 0.180 µg/kg.
Methods (brief)
ICP-MS (Perkin Elmer NexION 1000) after microwave acid digestion (AOAC 999.10; HNO3/H2O2). CRM: ERM-CE278k; recoveries 99–113%; RSD <2.03%. All mercury is total Hg; speciation not performed. For risk assessment, authors applied 80% MeHg fraction (EFSA convention) to derive methylmercury exposure. Weekly mollusk consumption rates: 9.61 g/week Turkey, 2.50 g/week Bulgaria (FAOSTAT 2020).
Implications
Certification: Farmed Mediterranean mussels from Turkish and Bulgarian aquaculture sites showed Cd 0.115–0.323 µg/g and tHg 0.019–0.117 µg/g, all within EU limits. One spring Pb outlier at M2 (0.372 µg/g) slightly exceeded Codex 0.30 µg/g; no systematic exceedance across farms or seasons.
Courses: Illustrates seasonal and geographic variation in mussel metal burden; spring often highest for multiple metals in this dataset. Se content (1.3–2.0 µg/g) provides context for Se-Hg interaction assessment.
App: Farmed Mediterranean mussels (TR/BG): Cd 0.115–0.323 µg/g, tHg 0.019–0.117 µg/g, Pb 0.096–0.372 µg/g (seasonal range), all below EU MRLs except one Pb outlier.