Overview
Valizadeh et al. measured As, Cu, Pb, Fe, Sn, Zn, Mn, Cd, and Hg in 90 canned bean samples (pinto beans across 8 brands, fava beans across 4 brands) distributed in Gilan Province, northern Iran. Analysis used ICP-OES (Varian 730-ES) for most elements and EPA Method 7473 (direct Hg analysis) for mercury; wet digestion with HNO3/HClO4/H2SO4. LOD: Hg 0.01 mg/L, Cd 0.0003 mg/L, As 0.01 mg/L, Pb 0.003 mg/L, Sn 0.02 mg/L. Certified reference material recoveries: Cd 99.1%, Pb 99.5%, As 99.4%. All As is total arsenic (ICP-OES; no speciation). Mercury was below the detection limit in all samples. Cadmium was detected in pinto bean samples (max 0.004 mg/kg, well below EU limit 0.1 mg/kg) but not in fava bean samples. The element ranking by mean concentration in both matrices was: Hg < Cd < As < Pb < Sn < Cu < Zn < Fe. Carcinogenic risk for 95th percentile consumers was 2.68×10⁻⁵ (pinto beans) and 1.30×10⁻⁵ (fava beans), above the generally accepted threshold of 10⁻⁶ but below 10⁻⁴; non-carcinogenic THQ was 0.3 for both types, below the hazard quotient threshold of 1.
Key numbers
All concentrations in mg/kg wet weight (mean ± SD where reported). Values from Fig. 1 and text.
| Element | Pinto beans (mean) | Fava beans (mean) | EU standard | INSO standard |
|---|---|---|---|---|
| Fe | 3.57 ± 0.008 | 7.079 ± 0.018 | 5 mg/kg | — |
| Sn | below Sn MRL | — | 200 mg/kg | 250 mg/kg |
| Zn | reported | — | — | — |
| Cu | reported | — | 5 mg/kg | — |
| Pb | reported (exceeds INSO 12968 in all samples) | reported | 0.1 mg/kg (EU) | 1 mg/kg (INSO) |
| As | — | 0.01 (minimum) | 200 µg/kg | — |
| Cd | 0.004 (max, below EU 0.1 mg/kg) | not detected | 0.1 mg/kg | — |
| Hg | <LOD (0.01 mg/L) | <LOD | 0.5 mg/kg | — |
Note: The text states Pb levels in all pinto and fava bean samples “exceeded the permissible limit in national standard 12,968” (Iran INSO; Pb limit 1 mg/kg in some canned product categories). All values remain below EU limits for most elements except the Pb comparison against INSO. As is total arsenic; iAs/tAs split not measured.
Non-carcinogenic TTHQ: 0.3 (pinto), 0.31 (fava), both <1. Carcinogenic risk 95th percentile: 2.68×10⁻⁵ (pinto), 1.30×10⁻⁵ (fava).
Methods (brief)
ICP-OES (Varian 730-ES) for As, Cd, Pb, Sn, Zn, Fe, Cu, Mn, Cr, Al; EPA Method 7473 (direct solid analysis) for Hg; wet acid digestion (HNO3/HClO4/H2SO4 at 150 °C). All arsenic is total arsenic; speciation not performed. Monte Carlo simulation (10,000 iterations, Crystal Ball) for risk assessment; consumption rates from Iranian national household basket standard INSO 12968.
Implications
Certification: Canned beans from Iranian Gilan Province market show Hg <LOD in all samples; Cd well below EU limit 0.1 mg/kg; Sn within EU limit 200 mg/kg. Pb is the principal element of concern under national (INSO) standards. Total arsenic concentrations are low.
Courses: Illustrates canned legume contamination profile; tin (from can lining) is a relevant analyte for canned product monitoring; brand-level variability was significant for Cu, As, Zn, Sn.
App: Canned pinto/fava beans (IR): Hg <LOD; Cd max 0.004 mg/kg; Fe highest element 3.6–7.1 mg/kg; Sn below 200 mg/kg EU limit. tAs minimum 0.01 mg/kg in fava beans.
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| Commit | Date | Change | Description |
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| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |