Smolikova et al. 2016 — Heavy metals in fish products sold in Czech Republic
This conference proceedings paper reports Cd, Pb, and tHg concentrations in 159 fish muscle tissue samples representing 33 species from 17 FAO fishing localities, purchased from fresh seafood shops in Brno, Czech Republic, using electrothermal atomic absorption spectrometry (ETAAS) for Cd and Pb, and a direct mercury analyzer (AMA 254) for tHg. Ten samples exceeded EU maximum permissible limits for mercury (Commission Regulation EC No 1881/2006: 0.5 mg/kg for most species, 1.0 mg/kg for selected predatory species), and three samples exceeded the cadmium limit (0.05 mg/kg); no lead exceedances were found. The most contaminated species were white marlin (tHg 10.42 ± 2.08 mg/kg, Cd 0.1809 ± 0.0362 mg/kg) and swordfish (tHg >1.0 mg/kg), highlighting the risk from apex predator billfish that are increasingly available in landlocked country markets; eight exceedance findings were reported to the EU RASFF system.
Key numbers
- White marlin (Tetrapturus albidus) tHg: 10.42 ± 2.08 mg/kg — highest in the study; LOD 0.1 µg/kg
- Swordfish (Xiphias gladius) tHg: >1.0 mg/kg EU limit exceeded; highest Pb: 0.0250 ± 0.0013 mg/kg
- Blue shark (Prionace glauca) tHg: >1.0 mg/kg EU limit exceeded
- Dusky grouper (Epinephelus marginatus) tHg: >0.5 mg/kg EU limit exceeded
- Nile tilapia (Oreochromis niloticus) tHg: 0.0031 ± 0.0002 mg/kg — lowest in study
- Cd exceedances (EU limit 0.05 mg/kg for general fish): tub gurnard 0.0950 ± 0.0047 mg/kg; ray 0.1203 ± 0.0060 mg/kg; white marlin 0.1809 ± 0.0362 mg/kg
- Swordfish (EU Cd limit 0.3 mg/kg): not exceeded in this study
- Pb: all samples below 0.3 mg/kg EU limit; highest in swordfish 0.0250 ± 0.0013 mg/kg
- LOD Cd: 0.12 µg/kg; LOD Pb: 3.11 µg/kg; LOD tHg: 0.1 µg/kg
- 14 RASFF alerts for Czech Republic since 2004 (6 Hg, 6 Cd, 2 both); this study contributed 8 new reports
Methods (brief)
159 fresh/frozen fish tissue samples (33 species, 17 FAO localities) from Brno markets. Microwave digestion (Ethos ONE, 210 °C, 1000 W, 30 min, 10 mL HNO3 1:1 in 600 mg sample) for Cd and Pb. ETAAS: Series AA 280 Agilent with Zeeman correction; pyrolysis 500 °C (Cd), 1000 °C (Pb); atomisation 1800 °C (Cd), 2100 °C (Pb); Pd/Mg(NO3)2 modifier. tHg by direct analysis: AMA 254 analyzer, 0.1 g sample, dry at 120 °C 90 s, decompose at 550 °C 180 s under O2 flow, cold-vapor AAS at 253.65 nm. Note: tHg only; no MeHg speciation performed.
Evidence tier B: conference proceedings publication (MendelNet 2016), not peer-reviewed journal. Data quality appears rigorous (RASFF submissions accepted), but publication venue limits tier assignment.
Implications
Certification: Apex predator billfish (marlin, swordfish, shark) carry extreme tHg levels that can exceed EU limits by an order of magnitude. These species are not typical HMT&C-certified product ingredients but are relevant context for seafood-category risk framing.
Courses: Useful illustration of biomagnification in the food web — white marlin at 10.42 mg/kg vs tilapia at 0.003 mg/kg, same market, same measurement protocol. RASFF reporting pathway as model for regulatory response.
App: Not applicable — species (marlin, shark, swordfish) are not typical ingredient-list items.