EFSA CONTAM Panel 2023 — Heavy metals and iodine in seaweeds and halophytes
This EFSA scientific opinion provides the most comprehensive EU-level assessment of heavy metal contamination in seaweeds and halophytes consumed as food. The panel analyzed 2,093 Cd, 1,988 Pb, 1,934 tAs, 920 iAs, and 1,499 tHg occurrence data points across seaweed species including laver (red algae), kombu/kelp (Laminaria/Saccharina), nori, spirulina, and chlorella. Laver red algae exhibited the highest Cd concentrations, reaching 1,675–1,676 µg/kg (wet weight). The opinion identifies seaweed consumption — particularly Asian-style dried seaweed products and seaweed-containing food supplements — as a meaningful contributor to dietary heavy metal exposure in European consumers, with iAs contribution from seaweed food supplements potentially approaching or exceeding the benchmark dose lower confidence limit (BMDL01) for some high-consumption scenarios.
Key numbers
- Laver (red algae) Cd: 1,675–1,676 µg/kg (mean range across data sets; wet weight basis)
- Number of occurrence data points: Cd n=2,093; Pb n=1,988; tAs n=1,934; iAs n=920; tHg n=1,499
- Kombu/kelp iAs concentrations among the highest observed for seaweed species
- Dietary exposure estimates calculated for mean and 95th percentile consumers across age groups
- WHO PTWI for Cd (25 µg/kg bw/week) and EFSA TWI (2.5 µg/kg bw/week) used as reference points
- BMDL01 for iAs: 0.3–8 µg/kg bw/day used for margin of exposure assessment
Methods (brief)
Systematic occurrence data compilation from EFSA’s comprehensive food consumption database (EFSA Comprehensive European Food Consumption Database). Analytical methods in cited studies: predominantly ICP-MS. Speciation: iAs distinguished from tAs using HPLC-ICP-MS in subset of studies. Basis: wet weight unless otherwise noted. CONTAM Panel dietary exposure assessment following EFSA guidance on probabilistic and deterministic approaches.
Implications
Certification: High Cd in red algae (laver) and iAs in kombu/kelp create elevated risk for any product containing these seaweed ingredients; directly relevant to seaweed-containing supplement certification. Courses: A-tier EU regulatory opinion establishing seaweed as a high-priority heavy metal source ingredient. App: Key data source for contamination_profile entries for seaweed, laver, kombu-kelp, spirulina, chlorella. Microbiome: Not directly applicable.