Armand et al. 2026 — Heavy metals in lettuce and cabbage from Behbahan, Iran

Armand and colleagues measured lead (Pb), chromium (Cr), cadmium (Cd), and nickel (Ni) in lettuce and cabbage purchased from ten retail outlets in Behbahan, a city in Khuzestan Province, southern Iran characterised by oil-and-petrochemical industrial development and recent agricultural intensification. Twenty samples of each vegetable (ten retail sites sampled twice four weeks apart) were analysed by ICP after HNO3 digestion. Cabbage carried roughly twice the total heavy-metal burden of lettuce; in both vegetables the concentration order was Cr > Ni > Pb > Cd. Mean cabbage concentrations of Pb (0.312 mg/kg wet weight) and Cr (0.699 mg/kg) exceeded the FAO/WHO-aligned guideline values used by the authors (0.3 and 0.5 mg/kg respectively), while all four metals in lettuce fell below the same guidelines. Probabilistic Monte Carlo simulation returned non-carcinogenic hazard indices below 1 for both vegetables (cabbage 1.52×10⁻¹; lettuce 4.58×10⁻¹), but total Excess Lifetime Cancer Risk above the 10⁻⁴ unacceptable threshold (cabbage 1.40×10⁻³; lettuce 4.14×10⁻³). Pb Margin of Exposure for cardiovascular endpoints was below 10 in both vegetables, interpreted by the authors as “of concern”.

Key numbers

• Sample: 20 samples each of lettuce and cabbage from 10 retail vegetable stores in Behbahan (uniform geographic distribution; two sampling rounds four weeks apart); n = 40 total. Each store-round sample contained 2 kg of vegetable.
• Method: ICP (not specified ICP-OES vs ICP-MS) after HNO3 digestion. Samples washed with distilled water, air-dried 24 h at room temperature, then 200 g sub-samples dried at 105 °C for 24 h, ground and homogenised; 500 mg dry-weight digested with 10 mL HNO3 at 80 °C, filtered, diluted to 25 mL with deionised water. Dry-weight concentrations converted to wet weight using the measured moisture content of each vegetable.
• Mean concentrations — cabbage (mg/kg wet weight): Pb 0.312, Cr 0.699, Cd 0.0756, Ni 0.633. Total ΣPb+Cr+Cd+Ni ≈ 1.720 mg/kg.
• Mean concentrations — lettuce (mg/kg wet weight): Pb 0.134, Cr 0.306, Cd 0.0601, Ni 0.320. Total ≈ 0.820 mg/kg.
• Per-site distributions for each of the four metals across S1–S10 stores are presented as nested radar plots in Fig. 2; visible label spread is roughly Pb 0.12–0.34, Cr 0.27–0.73, Cd 0.04–0.10, Ni 0.29–0.66 across both vegetables combined. Individual per-store and per-vegetable values are not readable to publication precision from the radar plot alone.
• Concentration order in both vegetables: Cr > Ni > Pb > Cd. Cabbage total metal burden was 2.09× lettuce total; mean Pb in the studied vegetables was on average 3.28× mean Cd.
• Estimated Daily Intake (EDI, mg/kg-BW/day, Table 3) — cabbage: Pb 2.41×10⁻⁴, Cr 5.39×10⁻⁴, Cd 5.83×10⁻⁵, Ni 4.88×10⁻⁴; lettuce: Pb 5.36×10⁻⁴, Cr 1.22×10⁻³, Cd 2.40×10⁻⁴, Ni 1.28×10⁻³.
• Hazard Quotients (Table 3) — cabbage: Pb 6.89×10⁻², Cr 3.59×10⁻⁴, Cd 5.83×10⁻², Ni 2.44×10⁻²; lettuce: Pb 1.53×10⁻¹, Cr 8.13×10⁻⁴, Cd 2.40×10⁻¹, Ni 6.40×10⁻². Highest HQ in both vegetables was driven by Pb (and Cd in lettuce); lowest by Cr.
• Hazard Index (sum of HQs): cabbage 1.52×10⁻¹, lettuce 4.58×10⁻¹, combined 6.10×10⁻¹. Both below 1: no significant non-carcinogenic risk under the authors’ exposure assumptions.
• Excess Lifetime Cancer Risk at the 95th-percentile probability (per metal, Fig. 3) — cabbage: Pb 2.05×10⁻⁶, Cr 3.78×10⁻⁴, Cd 3.67×10⁻⁴, Ni 6.49×10⁻⁴ (per Fig. 3 caption; the prose paragraph on p. 5 prints the cabbage Ni 95th-percentile value as 6.94×10⁻⁴ — a paper-internal Fig. 3 vs body-text discrepancy); lettuce: Pb 4.56×10⁻⁶, Cr 9.08×10⁻⁴, Cd 1.51×10⁻³, Ni 1.72×10⁻³. Total ELCR (average parameters): cabbage 1.40×10⁻³, lettuce 4.14×10⁻³ — both exceed the US EPA unacceptable threshold of 10⁻⁴.
• Margin of Exposure for Pb cardiovascular effects (BMDL 1.5 µg/kg-BW/day ÷ EDI): cabbage 6.22, lettuce 2.79. Both below 10, interpreted by the authors as “of concern”.
• Sensitivity analysis (Monte Carlo): metal concentration in vegetables and body weight were the dominant parameters driving calculated risk.
• Health guideline reference values used by the authors (Alimohammadi et al. 2020): Pb 0.3, Cr 0.5, Cd 0.2, Ni 2 mg/kg. Cabbage Pb (0.312) and Cr (0.699) exceeded these values; cabbage Cd (0.0756) and Ni (0.633) and all four metals in lettuce were below the guidelines.
• Risk-assessment parameters: ingestion rate 0.28 kg/day (lettuce) and 0.054 kg/day (cabbage); exposure frequency 365 day/year; exposure duration 70 year; body weight 70±15 kg; averaging time 25,550 day. (Table 1 prints these as 0.028 and 0.0054 kg/day, but back-calculation from Table 3 EDI values confirms 0.28 and 0.054 kg/day were used in the simulation — a typographic decimal-place error in Table 1.)
• Reference doses (mg/kg/day): Pb 0.0035, Cr 1.5, Cd 0.001, Ni 0.02. Cancer slope factors (mg/kg/day)⁻¹: Pb 0.0085, Cr 0.5, Cd 6.3, Ni 0.91.

Methods (brief)

Ten vegetable retail stores in Behbahan (uniform geographic distribution across the city) were sampled on two occasions four weeks apart, yielding 20 lettuce and 20 cabbage samples (40 total). Each sample was 2 kg of fresh vegetable transported immediately to the laboratory. Inedible/crushed parts were removed; samples were washed with distilled water and air-dried at room temperature for 24 h, then 200 g sub-samples were oven-dried at 105 °C for 24 h, ground and homogenised. 500 mg of dry sample was digested with 10 mL HNO3 at 80 °C, filtered, and adjusted to 25 mL with deionised water. Analysis used ICP (instrument vendor/model and ICP-OES vs ICP-MS not specified in the methods text). Dry-weight concentrations were converted to wet weight using each vegetable’s measured moisture content. Risk assessment used standard US-EPA equations for EDI, HQ, HI, and ELCR. Monte Carlo simulation was applied to body weight (70±15 kg) and per-site metal concentrations. Note on Cr speciation: only total chromium was measured. The authors nonetheless applied the Cr-VI cancer slope factor (0.5 (mg/kg/day)⁻¹) to total Cr in the carcinogenic-risk calculation, which materially overestimates ELCR-Cr if dietary Cr is predominantly Cr-III, as is typical for plant tissue. The cabbage Cr ELCR (3.78×10⁻⁴) and lettuce Cr ELCR (9.08×10⁻⁴) reported here should be interpreted with that caveat.

Implications

• Certification (HMTc): Cabbage mean Pb (0.312 mg/kg wet weight) exceeds the FAO/WHO-aligned 0.3 mg/kg guideline used by the authors and the Codex GSCTFF 0.10 mg/kg wet-weight ML for leafy vegetables. Cabbage mean Cr (0.699 mg/kg) exceeds the 0.5 mg/kg author guideline; however, the paper measured total Cr without speciation, and Cr-VI vs Cr-III speciation is essential before this value can support an HMTc-row decision. Lettuce values are below the same guidelines on a mean basis but Cd HQ in lettuce (0.240) is the second-highest single-metal HQ across either vegetable. Values reflect a specific industrial-impact region (Khuzestan oil-and-petrochemical corridor) and should not be treated as representative of global lettuce or cabbage baselines for HMTc P97/P45 pooling without explicit regional adjustment.
• Courses: Useful case study illustrating that non-carcinogenic HI can be below 1 while ELCR exceeds the 10⁻⁴ unacceptable threshold — the two metrics can diverge substantially. Also a clear example of the Cr speciation pitfall (applying a Cr-VI CSF to total Cr).
• App: Concentration values from this source are region-specific (Khuzestan industrial zone, Iran) and should be flagged as high-industrial-impact regional data rather than incorporated into generic lettuce or cabbage contamination profile baselines.
• Microbiome: Not applicable; no microbiome data.

Wiki pages this source may touch

• vegetables
• leafy-vegetables
• lettuce
• cabbage
• lead
• chromium
• cadmium
• nickel

Verification notes

• 2026-05-20 — Merge-enhance pass against the source PDF (raw/Manual Fetch Kimi /02_Vegetables_and_Vegetable_Products/02_Vegetables_and_Vegetable_Products/Probabilistic Carcinogenic and Health Risk Assessment of Heavy Metals in Lettuce and Cabbage.pdf). Pre-existing page dated 2026-05-13 was correct on cabbage/lettuce mean concentrations (cabbage Cd 0.0756; lettuce Cd 0.0601) but used a legacy raw_handle (“manual-fetch-kimi”) and truncated raw_path. Updated to current MFK_ raw_handle convention, restored the full PDF filename in raw_path, added raw_sha256 and near_duplicates fields, added ingredients/vegetables to the ingredients array, broadened matrices to [“vegetable”, “leafy-vegetable”], and rewrote the body to current source-page conventions (full EDI/HQ/ELCR tables, Pb-MOE, per-site ranges, parameter table).
• Abstract vs Table 2 / Table 3 internal Cd transposition: the abstract prints “(0.0756, 0.0601)” for cadmium “in (lettuce, cabbage)”, which would make lettuce Cd > cabbage Cd. Table 2, Table 3 EDI/HQ values, the conclusion’s total-burden sums (lettuce 0.820, cabbage 1.720 mg/kg), and the paper’s own statement that cabbage total burden is 2.09× lettuce all confirm cabbage Cd = 0.0756 and lettuce Cd = 0.0601. The abstract has the Cd pair transposed; the rest of the paper is self-consistent. The page reports the table/conclusion values.
• Table 1 ingestion-rate values (0.028 kg/day lettuce, 0.0054 kg/day cabbage) are inconsistent with the Table 3 EDI values by exactly 10×. Back-calculation from Table 3 (e.g., EDI_Pb_lettuce = 5.36×10⁻⁴ = 0.134 × IR / 70 ⇒ IR = 0.28 kg/day; EDI_Pb_cabbage = 2.41×10⁻⁴ = 0.312 × IR / 70 ⇒ IR = 0.054 kg/day) confirms IR = 0.28 and 0.054 kg/day were used in the simulation. Table 1 is a typographic decimal-place error. The Key numbers section reports the back-calculated values that match the simulation outputs.
• Cr speciation caveat preserved: the authors applied the Cr-VI cancer slope factor (0.5 (mg/kg/day)⁻¹) to total chromium, which overstates ELCR-Cr if dietary Cr is predominantly Cr-III as typical in plant tissue. This caveat is noted in both the Methods (brief) and Implications sections.
• No brand names appear in the source (retail sites are de-identified as S1–S10). No brand-firewall edits required.
• No new ingredient, product, regulation or metal slugs needed; all linked slugs exist.
• Routing audit run after enhancement: 0 unresolved entries, source not in malformed (advisory-only entry expected for products: [] raw-produce sources).
• 2026-05-20 — Fresh-context audit subagent verdict REVISE; two findings applied:
  • Cabbage Ni 95th-percentile ELCR: subagent flagged a paper-internal inconsistency between Fig. 3 caption (6.49×10⁻⁴) and the prose paragraph on p. 5 (6.94×10⁻⁴). Verified against the PDF directly — confirmed both values appear in the paper. Reported both in Key numbers with the discrepancy made explicit. Wiki had previously taken the Fig. 3 value silently.
  • Per-site ranges from Fig. 2 (S1–S10): subagent noted that radar-chart label readings to four decimal places are not defensible because the curves overlap and the panel layout makes vegetable/site attribution ambiguous. Verified — Fig. 2 is the only per-site source in the PDF; supplementary figures SF1–SF8 are cited for ELCR distributions but not for per-site concentrations. Replaced specific per-site ranges with a qualitative summary of the visible label spread across the radar; left publication precision to the mean values that are tabulated.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.