Valizadeh et al. 2023 — Potentially toxic elements in canned pinto and fava beans, Gilan Province, Iran
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.