EFSA CONTAM Panel 2015 — Nickel in food and drinking water: risk assessment
This EFSA CONTAM Panel opinion constitutes the primary European risk assessment for nickel in food and drinking water, requested by the Hellenic Food Authority (EFET) following concern about Ni in vegetables. The Panel established a TDI of 2.8 µg Ni/kg bw/day based on reproductive/developmental toxicity (post-implantation fetal loss in rats, BMDL10 = 0.28 mg Ni/kg bw, uncertainty factor 100). The Panel concluded that current chronic dietary exposure to Ni is of concern for the general population, with mean and 95th percentile values at or above the TDI for all age groups, especially toddlers and children. For Ni-sensitized individuals, an acute risk concern was also identified. This opinion was superseded in part by the 2020 update (see efsa-nickel-contam-2020).
Key numbers
Occurrence data (18,885 food samples, 15 EU countries, 2003–2012):
- Highest mean Ni levels: cocoa beans and cocoa products ~9.5 mg/kg; chocolate products ~3.8 mg/kg; legumes, nuts, oilseeds ~2 mg/kg.
- Grain and grain-based products: major contributor to exposure (widest consumption base).
- Drinking water: parametric value 20 µg Ni/L (EU Directive 98/83/EC); very small contribution to total exposure (0.0005–1.7% LB-UB across surveys).
- Left-censored data: 66% of analytical results (35% in food, 89% in drinking water).
Chronic dietary exposure:
- Mean, all surveys and age groups: 2.0 (elderly, min LB) to 13.1 µg/kg bw/day (toddlers, max UB).
- 95th percentile: 3.6 (elderly, min LB) to 20.1 µg/kg bw/day (toddlers, max UB).
- TDI: 2.8 µg Ni/kg bw/day — mean exposure in toddlers at or above TDI; 95th percentile above TDI for all age groups.
Acute dietary exposure:
- Toddlers mean: 14.3 µg/kg bw (range 13.2–15.5).
- Toddlers 95th percentile: 35.0 µg/kg bw (range 26.8–47.2).
- Adults mean: 2.5–4.9 µg/kg bw; 95th percentile: 5.5–11.8 µg/kg bw.
Health-based guidance values:
- Chronic TDI: 2.8 µg Ni/kg bw/day (from BMDL10 0.28 mg Ni/kg bw for post-implantation fetal loss, 2-generation rat study, uncertainty factor 100).
- Acute reference point for Ni-sensitized individuals: BMDL10 1.1 µg Ni/kg bw (from SCD dose-response studies in sensitized humans); MOE approach, MOE ≥ 10 = low concern; calculated MOEs considerably below 10 for all age groups.
Key food group contributors to chronic exposure: grain and grain-based products; non-alcoholic beverages (cocoa beverages in young, coffee in adults); sugar and confectionery (chocolate); legumes/nuts/oilseeds; vegetables; milk and dairy (in toddlers).
Methods (brief)
Analytical methods: ICP-MS (54% of reported methods) and AAS (42%). Lowest LOQ in food: 0.002 µg/kg (ICP-MS, alcoholic beverages); 1 µg/kg (AAS, fish/seafood and sugar/confectionery). Chronic and acute dietary exposure estimated by combining occurrence data (mean concentrations) with individual-level consumption data from EFSA’s Comprehensive Food Consumption Database. BMD modelling applied for TDI derivation.
Implications
Certification: Establishes the operative EU TDI for Ni (2.8 µg/kg bw/day). Cocoa and cocoa products have by far the highest occurrence levels (9.5 mg/kg for cocoa beans). Legumes and nuts (~2 mg/kg) are also high. Exposure concern is real across all age groups at mean levels; TDI is routinely exceeded at 95th percentile. No EU MLs for Ni in most food categories (exception: drinking water 20 µg/L). The 2020 update should be consulted for revised exposure estimates; this 2015 opinion remains the primary citation for the TDI derivation methodology.
Courses: Illustrates how sensitization (estimated prevalence up to 15% of general population) creates a separate, lower acute reference point than the chronic TDI. The SCD risk pathway (dermal sensitization leading to oral-challenge flare-up) is distinct from chronic systemic toxicity.
App: Confirms cocoa/chocolate and legumes/nuts as primary food-category drivers of Ni exposure. Grain products are high-volume contributors despite moderate Ni concentrations.