Ćwieląg-Drabek et al. 2025 — Cd, Pb, Cr, and Ni in five nut types on the Polish market
This study measured cadmium, lead, chromium, and nickel in 69 samples of five nut types commercially available in Poland: almonds, cashews, hazelnuts, peanuts, and walnuts. Using electrothermal atomic absorption spectrometry (ETAAS), the authors found that peanuts carried the highest mean concentrations of both Cd and Pb among the five types, while cashews had the highest Ni and almonds had the highest Cr. Health risk modelling across eight age groups identified moderate-to-high non-cancer hazard quotients (HQ > 1) for infants 6–11 months in multiple nut types, underscoring particular concern for early-life exposures when nut-containing foods are introduced into the diet.
Key numbers
Cadmium (mg/kg dry weight):
- Peanuts: highest mean (0.092 mg/kg = 92 µg/kg); no samples exceeded the EU ML of 0.1 mg/kg for peanuts (0.05 mg/kg for other nuts)
- Almonds: second highest
- Hazelnuts, walnuts, cashews: progressively lower; some samples below LOQ
- Below-LOQ rates: substantial fractions of all five types had Cd below LOQ (0.0032 mg/kg)
Lead (mg/kg dry weight):
- Peanuts: highest mean (0.229 mg/kg = 229 µg/kg); one sample reached 0.818 mg/kg, exceeding the EU ML of 0.2 mg/kg for peanuts
- Almonds: mean 0.22 mg/kg; second highest
- Cashews: majority below LOQ (0.032 mg/kg); lowest mean
- Sequence: peanuts > almonds > hazelnuts > walnuts > cashews
Nickel (mg/kg dry weight):
- Cashews: highest mean (6.434 mg/kg = 6,434 µg/kg)
- Peanuts: second highest
- Walnuts, hazelnuts: intermediate
- Almonds: lowest (1.299 mg/kg = 1,299 µg/kg)
- Sequence: cashews > peanuts > walnuts > hazelnuts > almonds
Chromium (mg/kg dry weight):
- Almonds: highest mean (0.253 mg/kg = 253 µg/kg)
- Cashews and hazelnuts: similar second-tier levels
- Peanuts: lower
- Walnuts: lowest mean (0.133 mg/kg = 133 µg/kg)
- Sequence: almonds > cashews and hazelnuts > peanuts > walnuts
LOD/LOQ: Cd LOD 0.0017 mg/kg, LOQ 0.0032 mg/kg; Pb LOD 0.018 mg/kg, LOQ 0.032 mg/kg; Ni LOD 0.27 mg/kg, LOQ 0.44 mg/kg; Cr LOD 0.034 mg/kg, LOQ 0.06 mg/kg
Health risk: HQ > 1 for all four metals in the 6–11-month infant group under scenarios B–J (10–100 g/day consumption) using mean and maximum concentrations. HI > 1 (combined hazard across all four metals) was also found at multiple consumption scenarios for this age group. Lifetime cancer risk from Pb and Cr in walnuts was within acceptable bounds (ILCR analysis).
Methods (brief)
Electrothermal AAS (ETAAS) using a Perkin-Elmer AAnalyst 800 graphite furnace. Samples were wet-digested in HNO3 + HClO4. LODs and LOQs were calculated from 20 independent blank samples. The country of origin was recorded for each sample; geographic breakdown was used in supplementary tables. Note: chromium was reported as total Cr; no Cr speciation was performed, so the reported values reflect Cr(III) + any Cr(VI) together and should not be used as Cr(VI) estimates.
Implications
Certification: Nickel concentrations in cashews (mean 6,434 µg/kg) and peanuts are notably elevated relative to other nut types; relevant for HMT&C analyte coverage of Ni in nut-containing products. The single peanut sample with Pb at 818 µg/kg (country: unspecified) signals that origin sourcing for peanuts matters. Cd in peanuts is at the EU ML boundary, consistent with Cd risk prioritization in that commodity.
Courses: Health risk findings for the 6–11-month infant group illustrate how small body weight amplifies per-kg dose from normal nut-containing food servings; a useful case study in pediatric exposure calibration.
App: Provides mean concentrations per nut type suitable for per-serving Cd, Pb, Ni, and Cr estimates in products containing peanuts, almonds, hazelnuts, walnuts, or cashews. Use values as dry-weight basis; conversions needed for moisture-adjusted fresh or paste forms.