Bae et al. 2023 — Heavy metals in commercial tuna (Korea)
This study measures methylmercury (MeHg), total mercury (tHg), lead (Pb), cadmium (Cd), and arsenic (As) in 31 commercial tuna product samples purchased in the Korean market. The paper provides mean concentrations with standard deviations and compares findings against Korean and international maximum residue limits. It reports that 9.7% of tuna samples exceeded the Korean maximum residue limit for methylmercury.
Key numbers
Reported mean concentrations (wet weight):
- MeHg: 0.56 ± 1.47 mg/kg (= 560 ± 1,470 ppb); 9.7% of samples exceeded the Korean MRL
- Pb: 33.95 ± 3.74 µg/kg (= 33.95 ± 3.74 ppb)
- Cd: 14.25 ± 2.19 µg/kg (= 14.25 ± 2.19 ppb)
- As (total): 1.46 ± 1.89 mg/kg (= 1,460 ± 1,890 ppb)
n=31 commercial tuna products, jurisdiction: Korea (KR).
The high MeHg relative standard deviation (SD nearly 3× the mean) indicates substantial variability across products; some samples far exceed the mean. The Pb and Cd means are well below Korean regulatory limits; the tAs is total arsenic (dominated by arsenobetaine in marine fish) and is not directly comparable to inorganic arsenic limits.
Health risk assessment: target hazard quotients (THQ) calculated for adult and child consumers; mercury THQ exceeded 1 for frequent consumers in the highest-exposure scenario.
Methods (brief)
ICP-MS for Pb, Cd, and tAs. Cold vapor atomic absorption spectrometry (CVAAS) or ICP-MS for total mercury; MeHg by HPLC-CVAAS or equivalent speciated method. Digestion by microwave acid digestion. Certified reference materials used for QC. Sample preparation details not fully specified in the available text.
Limitation: n=31 is a relatively small sample for characterizing the full Korean market distribution. High SD for MeHg suggests heterogeneous sourcing (species mix, troll-caught vs. canned).
Implications
Certification: MeHg data from tuna is directly relevant to HMT&C tuna and seafood product standards. 9.7% exceedance of Korean MRL at 0.5 mg/kg is a meaningful signal; the tail of the distribution drives certification risk.
Courses: Good case study on why speciation matters in seafood — tAs is high but is largely organoarsenic (arsenobetaine), while MeHg is the true health driver.
App: Contributes to contamination_profile for tuna and seafood at the product layer. MeHg 560 ppb mean; Pb 34 ppb; Cd 14 ppb.
Microbiome: Not applicable.