Torović et al. 2024 — Mercury in fish oil supplements: Serbia and Srpska market
This conference abstract (presented at FENS 2023, Belgrade; published 2024 in MDPI Proceedings) reports total mercury concentrations in 42 fish oil supplements from the Serbian and Bosnian-Srpska markets, determined by a direct mercury analyzer. Total mercury ranged from 0.001 to 0.0057 mg/kg, with a mean of 0.0019 ± 0.0009 mg/kg — well below the EU maximum level for food supplements of 0.1 mg/kg. Risk assessment against both the US EPA oral reference dose (RfD of 0.0001 mg/kg bw/day) and EFSA tolerable weekly intake (TWI of 0.0013 mg/kg bw) used the precautionary assumption that total mercury equals methylmercury (MeHg accounts for 75–98% of total mercury in fish). Mean consumer exposure represented 0.042% of RfD and 0.023% of TWI; the highest individual exposure reached 0.24% of RfD and 0.13% of TWI. The authors conclude that mercury risk from fish oil supplements is negligible even for pregnant and nursing women.
Key numbers
- tHg range: 0.001–0.0057 mg/kg (1.0–5.7 ppb), n = 42
- tHg mean ± SD: 0.0019 ± 0.0009 mg/kg (1.9 ± 0.9 ppb)
- EU maximum level for supplements: 0.1 mg/kg (100 ppb) — all samples below this at < 6% of the limit
- MeHg RfD (US EPA): 0.0001 mg/kg bw/day; mean exposure = 0.042% of RfD
- MeHg TWI (EFSA): 0.0013 mg/kg bw; mean exposure = 0.023% of TWI
- Maximum individual exposure: 0.24% of RfD, 0.13% of TWI
Speciation note: the study measured total Hg (tHg) only. The risk assessment applied the precautionary assumption tHg = MeHg, which is the more conservative approach. This paper does not provide species-resolved MeHg data.
Methods
Direct mercury analyzer (not specified in abstract but standard for this application is a thermal decomposition amalgamation instrument). No sample preparation required. Risk assessment applied manufacturer-recommended intake doses for the supplement and EFSA/EPA toxicological reference values for MeHg.
Limitations: This is a conference abstract (2 pages), not a full peer-reviewed article. Sample descriptions and individual-product results are not provided. The abstract does not name the specific supplements tested or describe how 42 products were selected.
Implications
Certification: Provides market-surveillance data supporting the position that fish oil supplements at recommended doses contribute negligibly to mercury exposure even under the conservative tHg = MeHg assumption. Useful as supporting context for HMT&C supplement product guidance.
Courses: Illustrates the precautionary principle applied to tHg/MeHg speciation in risk assessment for supplement products.
App: Supports a low-risk classification for fish oil supplements with respect to mercury at current market concentrations in the Serbia/Srpska market.