Heshmati et al. 2020 — Total Pb and Cd in eight Hamadan-market vegetables and cereals (western Iran) by GF-AAS with adult exposure and risk assessment

This Iranian market-basket survey quantifies total Pb and total Cd in eight commodities — potato, onion, tomato, lettuce, leek, carrot, wheat, and rice — purchased from local markets, supermarkets, and grocery stores in Hamadan province, western Iran, between August 2017 and February 2018. Fifty composites per commodity (n=400 total) were microwave-digested in HNO₃/H₂O₂ and quantified by graphite-furnace atomic absorption spectrometry (Thermo Scientific CE 3300) at 217 nm (Pb) and 228.8 nm (Cd). All eight commodity means for both Pb and Cd were below the EU 1881/2006 maximum allowable concentrations (MAC) cited by the authors, but Pb exceeded the MAC in 4 % of carrot samples, 10 % of wheat samples, and 8 % of rice samples; no Cd sample in any commodity exceeded the EU MAC. Adult (70 kg, single-cohort) exposure assessment used Iranian per-capita consumption (68 g/d potato; 39 g/d onion, leek, carrot; 109 g/d tomato; 58 g/d lettuce; 322 g/d wheat; 322 g/d rice from Table 4) and yielded total Cd EDI 0.49 µg/kg bw/day (below JECFA PTDI ≈ 0.8 µg/kg bw/day), all per-commodity Cd THQ values < 1, and all per-commodity Pb MOE values > 1 (range 2.12 wheat / 2.69 rice / 42.86 potato / 133.33 onion), supporting the authors’ conclusion of no significant non-carcinogenic health risk from Pb and Cd exposure through these eight commodities for the adult population.

Key numbers

Method validation (Table 1, p. 103)

Spike recoveries (three spiking levels 0.025, 0.25, 0.5 µg/g): 95.14–106.98 %. RSD < 2 %.

Moisture content (% w/w, oven 105 °C to constant weight)

Potato 74.34; onion 89.20; tomato 94.27; lettuce 93.28; leek 90.48; carrot 86.35; wheat 11.22; rice 13.04.

Table 2 — Lead concentration in eight commodities (n=50 per commodity)

Parenthetical letters (A–D) within a column denote Duncan’s test significant-difference groups (P < 0.05); columns share their own letter alphabet.

Table 3 — Cadmium concentration in eight commodities (n=50 per commodity)

Table 4 — Adult exposure and non-carcinogenic risk (70 kg adult; per-capita consumption from ISIRI 2010 No. 12968)

Total Cd EDI sum across all eight commodities = 0.490 µg/kg bw/day (text §“Risk assessment” p. 105), below the JECFA PTDI of 0.8 µg/kg bw/day derived from the PTMI of 25 µg/kg bw/month.

Risk-assessment parameters (§“Health risk assessment”, p. 102; §“Risk assessment”, p. 105)

• Body weight (single adult cohort): 70 kg.
• RfD Cd: 1 µg/kg bw/day (USEPA, oral chronic).
• JECFA Cd PTMI: 25 µg/kg bw per month (≈ 0.8 µg/kg bw/day PTDI).
• JECFA Pb: PTWI withdrawn; dietary intake of 1.2 µg Pb/kg bw/day cited as the comparator that “would only raise adult blood pressure by 1 mm Hg,” with MOE = 1.2 / EDI; MOE > 1 → risk negligible.
• THQ formula (Eq. 2): THQ = EDI / RfD.
• TTHQ (Eq. 3): TTHQ = Σ THQ across commodities.
• MOE formula (Eq. 4): MOE = 1.2 (µg/kg bw/day) / EDI Pb.
• EU 1881/2006 MAC values cited by the authors (Tables 2–3): Pb 0.10 mg/kg ww for potato, onion, tomato, carrot; 0.30 mg/kg ww for lettuce and leek; 0.20 mg/kg ww for wheat and rice. Cd 0.10 mg/kg ww for potato, onion, tomato, carrot; 0.20 mg/kg ww for lettuce, leek, wheat, and rice.

EDI rank-order statements

The text (p. 105) states two decreasing rank-orders that are inconsistent with the EDI columns of Table 4 as published:

• Pb (text): wheat > rice > lettuce > leek > carrot > potato > onion > tomato.
• Pb (Table 4 values): wheat (0.566) > rice (0.446) > potato (0.028) > leek (0.022) > lettuce (0.018) > carrot (0.016) > tomato (0.011) > onion (0.009).
• Cd (text): rice > wheat > tomato > lettuce > leek > potato > onion > carrot.
• Cd (Table 4 values): rice (0.225) > wheat (0.212) > potato (0.021) > leek (0.008) > carrot (0.007) > lettuce (0.006) ≈ onion (0.006) > tomato (0.005).

See Verification notes — Table 4 numerics are internally consistent (EDI = C × FIR / bw recomputes verbatim from the table’s own consumption and concentration values); the text rank-orders are typographic, not data, errors.

Exceedance summary (counts derived from Tables 2–3 percentages)

• Pb above EU MAC: carrot 2/50 (4 %), wheat 5/50 (10 %), rice 4/50 (8 %); zero in potato, onion, tomato, lettuce, leek.
• Cd above EU MAC: zero in every commodity.

Methods (brief)

Study design. Cross-sectional market-basket survey of eight commodities across Hamadan province, western Iran (capital Hamadan, lat 33°33′–35°48′ N, long 47°45′–49°36′ E), August 2017 – February 2018. Fifty composites per commodity, each composite 2.5 kg, with a 1 kg subsample processed for analysis. n=400 total composites; measurements in triplicate per composite.

Sample preparation. Each composite washed with distilled water, sliced, oven-dried at 75 °C (Memmert GmbH, Schwabach, Germany), finely powdered in a mixer. 0.5 g of dried powder + 3:1 (v/v) HNO₃ (65 %) / H₂O₂ (35 %) digested in a Teflon vessel by a five-step microwave program (1.5 min 240 W → 2.5 min 100 W → 1.5 min 240 W → 4 min 300 W → 4 min 600 W). 10 mL deionised water added; filtered through 0.45 µm membranes. Moisture content determined separately on a second aliquot dried at 105 °C to constant weight (expressed % w/w).

Containers. Acid-washed per a previously published in-group protocol (Heshmati et al. 2017, ref [24]).

Instrumentation. Graphite-furnace atomic absorption spectrophotometer (CE 3300, Thermo Scientific, Waltham, MA) with hollow-cathode lamps at 217 nm (Pb) and 228.8 nm (Cd).

Calibration & QC. External calibration over 2.5–1000 µg/L (Cd Y = 0.21345X + 0.0118, r² 0.9972; Pb Y = 0.06541X + 0.03456, r² 0.9987). LOD = 3σ_blank/slope, LOQ = 10σ_blank/slope (Cd LOD 0.220 / LOQ 0.682 µg/kg; Pb LOD 0.350 / LOQ 1.090 µg/kg). Recovery validation at 0.025, 0.25, 0.5 µg/g spike levels across both vegetable and cereal matrices yielded 95.14–106.98 % recovery, RSD < 2 %. No certified reference material (CRM) reported; recovery is the sole accuracy control.

Speciation. Total Pb and total Cd only. No arsenic or mercury panel; no Pb or Cd species fractionation.

Reporting basis. Both wet-weight and dry-weight means are tabulated (Tables 2, 3, columns 4–5); risk-assessment EDIs (Table 4) use wet-weight mean concentrations and Iranian per-capita raw-commodity consumption figures (FIR, g/day) from Institute of Standards and Industrial Research of Iran (ISIRI) Standard No. 12968 (2010). All vegetables are treated as raw/as-consumed; wheat and rice as bulk grain.

Risk-assessment formulas. EDI (µg/kg bw/day) = C_mean (mg/kg ww) × FIR (g/day) / bw (kg), with implicit unit handling that yields µg/kg/day (recomputed verbatim from Table 4 inputs). THQ = EDI / RfD; TTHQ = Σ THQ across commodities; MOE = 1.2 (µg/kg bw/day) / EDI Pb. RfD Cd = 1 µg/kg bw/day (USEPA, oral chronic). bw = 70 kg, single adult cohort.

Statistics. SPSS v16.0 (SPSS Inc., Chicago, IL). One-sample t-test for comparison of analyte means to EU MAC values. One-way ANOVA with Duncan post-hoc test for between-commodity comparisons. α = 0.05.

Geographic context. Hamadan province population ~1,758,268; area 19,545.82 km². Authors describe the regional climate as cold winters and mild summers, citing Sadeghi et al. 2017 for the rainfall-altitude distribution. The paper does not investigate contamination pathway (soil, irrigation water, fertilizer, post-harvest handling, packaging) for any exceedance.

Implications

This source contributes Iranian market-basket occurrence data for total Pb and total Cd in eight bulk vegetable and cereal commodities sampled across one western Iranian province (Hamadan), plus an adult-only single-cohort exposure assessment using ISIRI 2010 per-capita consumption values. Its principal contributions to the wiki evidence pool:

• Bulk vegetable Pb occurrence (mg/kg ww and mg/kg dw) for six produce commodities in an Iranian regional market context: potato 0.029 / 0.110, onion 0.016 / 0.138, tomato 0.007 / 0.118, lettuce 0.022 / 0.319, leek 0.040 / 0.388, carrot 0.029 / 0.202. Leek and lettuce sit at or near the EU 0.30 mg/kg ww leafy-vegetable Pb MAC on a wet basis; on a dry basis lettuce 0.319 and leek 0.388 exceed the corresponding 0.30 mg/kg figure but the regulation is expressed in wet weight, so the wet-basis comparison is the operative one. Useful as central-tendency Iranian-market occurrence data for downstream pooling.
• Bulk grain Pb occurrence: wheat 0.123 mg/kg ww (10 % MAC exceedance at 0.20 mg/kg) and rice 0.097 mg/kg ww (8 % MAC exceedance). Adds Iranian-market occurrence data to the bulk-grain Pb evidence pool alongside other regional Iranian surveys (Tabriz, Shahre Rey, Isfahan, Kermanshah cited in the paper’s discussion).
• Bulk vegetable Cd occurrence (mg/kg ww and mg/kg dw): potato 0.022 / 0.088, onion 0.011 / 0.106, tomato 0.003 / 0.060, lettuce 0.007 / 0.108, leek 0.015 / 0.155, carrot 0.013 / 0.094. All below EU MAC on the wet basis; useful as low-to-moderate-end Cd occurrence values.
• Bulk grain Cd occurrence: wheat 0.046 mg/kg ww, rice 0.049 mg/kg ww; both below the EU 0.20 mg/kg ww MAC and below the contemporaneous Kermanshah-province Pirsaheb et al. 2016 wheat figure (0.41 mg/kg dw) cited in the discussion.
• Carrot, wheat, and rice MAC exceedance rates at the sample level (4 %, 10 %, 8 % respectively) document that despite below-MAC commodity means, a non-trivial fraction of sampled lots exceed the regulatory ceiling — useful evidence for downstream Part 9 synthesis of within-commodity Pb variability and for product-page Levers framing.
• Adult exposure parameter set: documents Iranian per-capita raw-commodity consumption (FIR) values from ISIRI Standard No. 12968 (2010) and the resulting EDIs at 70 kg body weight for one ranking of bulk vegetables and cereals; demonstrates that even with wheat and rice each contributing 322 g/day, the total Cd EDI of 0.49 µg/kg bw/day stays below the JECFA 0.8 µg/kg bw/day PTDI.
• Methodological reference point: GF-AAS LOD 0.220 µg/kg (Cd) and 0.350 µg/kg (Pb) with microwave digestion and HNO₃/H₂O₂; no CRM-anchored accuracy validation. The absence of CRM validation is the primary contributor to B-tier evidence grading.

Sample size is moderate (50 composites per commodity, triplicate measurements). The single-province sampling footprint, single-year window (August 2017 – February 2018), 70-kg adult-only exposure cohort, and lack of CRM-anchored accuracy validation limit the paper’s standalone authority; pools with other Iranian and regional vegetable/cereal surveys rather than anchoring any standalone characterisation. The paper does not measure As, Hg, Ni, Al, or Sn; it does not investigate Pb or Cd contamination pathway; and the EDI rank-order statements in the text contradict the EDI values printed in Table 4 (see Key numbers and Verification notes).

Wiki pages this source may touch

• lead
• cadmium
• potatoes
• onions
• tomato
• lettuce
• carrots
• wheat
• rice
• vegetables
• cereals
• leafy-vegetables
• root-vegetables
• non-root-vegetables
• root-tuber-vegetables
• non-root-vegetables
• leafy-vegetables-other
• rice-bulk-grain
• other-grain-products
• eu-1881-2006-contaminants-superseded
• jecfa-cadmium-ptmi
• jecfa-lead-ptwi-withdrawn
• epa-iris-cadmium-rfd

Verification notes

• Cite-key choice. heshmati2020-iran-vegetables-cereals-pb-cd follows the descriptive-suffix convention (first author, year, region, commodity class, analytes). DOI is the canonical identity; cite-key is a human-readable handle.
• Evidence tier B. Peer-reviewed in Journal of Food Protection (IAFP); single-province sampling footprint (Hamadan), single-year window (Aug 2017 – Feb 2018), no CRM-anchored accuracy validation (recovery only), and a 70-kg adult single-cohort exposure assessment that excludes children and elderly. Sample size (50 composites × 8 commodities × triplicate) is adequate but does not by itself reach A-tier without methodology anchoring.
• Paper-internal inconsistency #1 — Text vs. Table 4 consumption values. Page 3 §“For Pb risk assessment” reads “daily consumption of potatoes, onions, tomatoes, lettuce, leeks, carrots, wheat, and rice was considered to be 68, 39, 109, 58, 39, 39, 332, and 332 g, respectively (27).” Table 4 prints 322 g/day for both wheat and rice, and the Table 4 EDIs are internally consistent with 322 (e.g., wheat Pb EDI = 0.123 × 322 / 70 = 0.566 ✓; with 332 the EDI would be 0.584). The wiki page reports 322 g/day per Table 4 and flags the 332 in the text as a typographic error.
• Paper-internal inconsistency #2 — EDI rank-order statements vs. Table 4. The text’s Pb-EDI decreasing order (“wheat > rice > lettuce > leek > carrot > potato > onion > tomato”) and Cd-EDI decreasing order (“rice > wheat > tomato > lettuce > leek > potato > onion > carrot”) do not match the EDI values printed in Table 4. The correct rank-orders from Table 4 are: Pb wheat > rice > potato > leek > lettuce > carrot > tomato > onion; Cd rice > wheat > potato > leek > carrot > lettuce ≈ onion > tomato. Both Key numbers and Implications report the Table 4 values; the text statements are flagged as writing errors and are not reused downstream.
• Paper-internal inconsistency #3 — Abstract precision. The abstract reports rice Cd as “0.049 ± 0.04 mg kg⁻¹ wet weight” (one significant figure on SD) while Table 3 reports “0.049 ± 0.040 mg kg⁻¹ wet weight” (two significant figures). This is precision/formatting only, not a data discrepancy; the wiki page uses Table 3 precision.
• Frontmatter discipline. All ingredient and product slugs verified against the 2026-05-18 taxonomy snapshot. Eight commodities mapped to ingredient slugs (potatoes, onions, tomato, lettuce, carrots, wheat, rice) plus three umbrella ingredients (vegetables, cereals, leafy-vegetables, root-vegetables, non-root-vegetables). Leek is not present in the ingredient taxonomy snapshot (the snapshot has lettuce, leafy-greens, leafy-vegetables but no leek); the leek-specific values are captured in matrices: [leek] and route through the umbrella leafy-vegetables and vegetables ingredient slugs. Auto-stub creation for leek, if/when freq-2 is crossed by other sources, is the routing-layer’s job, not this page’s. Five product slugs (root-tuber-vegetables for potato + carrot; non-root-vegetables for onion + tomato; leafy-vegetables-other for lettuce + leek; rice-bulk-grain for rice; other-grain-products for wheat) all in the snapshot.
• Matrices vocabulary. Bare-string matrices include the eight commodity-specific terms (potato, onion, tomato, lettuce, leek, carrot, wheat-grain, rice-grain) plus the umbrella vegetable and cereal-grain per the matrices controlled vocabulary used in adjacent Iranian-survey source pages.
• Speciation. Total Pb and total Cd only — no As/Hg panel, no Pb or Cd species fractionation. Frontmatter metals: reflects this ([Pb, Cd]).
• Basis. Tables 2–3 report both wet-weight and dry-weight means; the wiki page tabulates both. Table 4 risk-assessment EDIs use wet-weight mean concentrations × per-capita raw-commodity consumption, which matches the regulatory basis the authors compare against (EU 1881/2006 MAC values are stated in mg/kg ww). No basis conversion required for downstream routing of the wet-weight values; the dry-weight values are retained as a parallel column for downstream cross-comparison with dry-basis Iranian-cereal surveys (e.g., Ataee et al. 2016 Kermanshah, Pirsaheb et al. 2016 Kermanshah).
• Sampling year. Stated as August 2017 – February 2018 (page 2, §“Samples collection”).
• Brand firewall (Part 12). No brand-name attribution to contamination values — the paper identifies samples only by commodity and aggregates across three retail venue types (local markets, supermarkets, grocery stores) in Hamadan province. Methods-section vendor names retained per the 2026-05-17 vendor-name exception: Thermo Scientific CE 3300 (GF-AAS), Memmert GmbH (oven), Merck (standard solutions and reagents), SPSS Inc. (v16.0 statistical software).
• Wiki/HMTc firewall (Part 2). No threshold proposals, no consumer-audience advisories, no synthesis claims against other papers beyond paper-discussion-citation pass-through (e.g., the paper’s reference to Pirsaheb et al. 2016 Kermanshah cereals and Pajević et al. 2018 Serbian vegetables are noted in Implications as comparators the paper itself draws, not as wiki-side synthesis claims).
• Regulatory citations. The paper cites EU Commission Regulation 1881/2006 (Off. J. Eur. Union L 364, 5; ref [15]) for vegetable and cereal MAC values; JECFA 2010 WHO TRS 960 (ref [32]) for the Cd PTMI of 25 µg/kg bw/month and for the withdrawal of the Pb PTWI in favour of the 1.2 µg/kg bw/day MOE comparator. EU 1881/2006 is captured in the wiki page’s regulatory-context routing as eu-1881-2006-contaminants-superseded (superseded by EU 2023/915 in 2023; the paper’s sampling window predates the supersession, so the cited values were operative at the time of the survey).
• Pb wavelength. Paper reports 217 nm (Pb) and 228.8 nm (Cd). 217.0 nm is a recognized secondary Pb GF-AAS line (the primary is 283.3 nm); the paper does not justify the choice but the calibration r² of 0.9987 and the 95–107 % recovery support the working selection. Documented for downstream method-comparison cross-reference.
• Data integrity. All 8 commodity × 2 metal × (mean ww, SD ww, mean dw, SD dw, range min, range max, n below MAC, n above MAC) = 128 Table 2/3 cells transcribed from the original PDF (pages 103, 104). All Table 4 cells (8 commodities × 7 columns + TTHQ) likewise transcribed. Table 1 method-validation cells (Cd and Pb × 5 columns) likewise transcribed. EDI = C × FIR / bw recomputed verbatim for all eight commodities and both metals against the Table 4 column inputs, with no internal arithmetic discrepancies in Table 4 itself. The 332-vs-322 g/day discrepancy and the EDI rank-order statements are the two paper-internal contradictions identified; both flagged above. No other contradictions.

Page history

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