Pirsaheb et al. 2015 — Pb, Cd, Cr, Ni, Zn, Cu in Kermanshah-market cereals and pulses by ICP-OES

This survey reports total concentrations of two toxic metals (Pb, Cd), total chromium, nickel, and two essential micronutrients (Zn, Cu) in seven retail-market cereal and pulse commodities — rice, wheat, corn, peas, lentil, bean, split peas — purchased from stores in Kermanshah city, west Iran, in 2014, and quantified by inductively coupled plasma-optical emission spectrometry (ICP-OES). Mean Pb concentrations exceeded the Codex Alimentarius cereal limit (0.2 mg/kg) and the Iranian national standard (0.15 mg/kg) in every commodity; mean Cd exceeded the Codex 0.1 mg/kg ceiling in four of seven commodities (wheat, corn, bean, split peas) and the Iranian 0.06 mg/kg ceiling in six of seven commodities (all commodities except rice, whose 0.055 mg/kg mean was below both ceilings). Estimated weekly intakes (EWIs) derived from a 110 g/day per-capita cereal-consumption assumption and a 60 kg body-weight reference remained below JECFA provisional tolerable weekly intakes (PTWIs) for all six metals across all seven commodities. Method validation against three certified reference materials (two Chinese cereal CRMs and SRM 1568b) returned recoveries of 87.5-109 %.

Key numbers

Reference values cited in the paper for comparison:

PTWI reference values used for the risk assessment (μg/kg body weight per week):

Mean concentrations across all brand-samples per commodity (mg/kg dry weight), and per-commodity ranges where the paper reports them (Figures 1-2 and prose, pp. 3-5):

Notes on the range structure: the paper reports an explicit per-brand range for rice Pb (0.99-2.3 mg/kg) but does not report explicit per-commodity Pb ranges for the other six commodities, only the means above. For Cr, Ni, Zn and Cu the paper reports across-all-samples ranges and per-commodity means but not per-commodity ranges. Across-all-samples extrema:

Cd extrema across all samples: lowest 0.033 mg/kg in a peas brand, highest 1.99 mg/kg in a wheat brand (per prose, p. 4).

Ni was below detection in six rice brands, one wheat brand, and one corn brand. Ni was detectable in all pea, lentil, bean, and split-pea brands.

Codex / Iranian exceedance pattern (paper’s framing, Figures 1-2):

• All commodity-mean Pb concentrations were above both the Codex Alimentarius 0.2 mg/kg cereal limit and the Iranian 0.15 mg/kg cereal limit.
• Mean Cd in rice was below both Codex (0.1 mg/kg) and Iranian (0.06 mg/kg) limits at 0.055 mg/kg, but individual rice brand-means in three rice categories exceeded the Iranian 0.06 mg/kg limit per the prose on p. 4.
• Mean Cd in wheat (0.41), corn (0.29), bean (0.13), split peas (0.15) exceeded both limits. Mean Cd in peas (0.09) and lentil (0.07) was below the Codex 0.1 mg/kg ceiling but above the Iranian 0.06 mg/kg ceiling.

Estimated weekly intake (EWI) of each metal at a Kermanshah-population per-capita consumption assumption of 110 g/day × 7 = 770 g/week, with a 60 kg body-weight reference (Table 3, p. 5; units μg/kg body weight per week):

The single-commodity EWI for Pb in bean (24.38 μg/kg body weight per week) approaches the PTWI ceiling (25 μg/kg bw/week) at 97 % of the ceiling; bean Ni EWI is 91.7 % of the Ni PTWI. The paper notes that the EWI calculation considers only one commodity at a time and does not account for cumulative exposure across all cereal consumption.

Certified reference material accuracy (Table 2, p. 3; certified values in μg/g):

Method limits of detection (LODs) ranged from 0.1 to 0.35 μg/kg across the six metal channels.

Methods (brief)

Sample collection. 150 packed cereal samples were collected from retail stores in Kermanshah city, west Iran, in 2014. The samples covered seven commodity types (rice, wheat, corn, peas, lentil, bean, split peas) and 3-11 brands per commodity (mix of imported and domestically cultivated). For each brand, three ~50 g samples were randomly drawn. Cereal samples were passed through a 50-mesh (<0.30 mm) sieve, sealed in plastic boxes, and stored at room temperature until analysis.

Sample preparation. Each sample was washed with tap water, rinsed with distilled water, dried at 40 °C for 100 min, milled to powder in a stainless-steel-blade commercial blender (Mixer B-400, BÜCHI, Flawil, Switzerland), homogenised, and sieved through 50 mesh. One gram of homogenised powder was weighed into a porcelain crucible and dry-ashed in a muffle furnace (Carbolite CWF 1200, Hope Valley, UK) by stepwise ramp to 500 °C over 3 h, then held at 500 °C for 8 h. The residue was dissolved in 8 mL of 3 M HNO₃ + 30 % H₂O₂ (3:1), filtered through Whatman paper into a 25 mL volumetric flask, made to mark with deionised water, and stored at −20 °C until analysis. Each sample was analysed in triplicate.

Instrumentation. Inductively coupled plasma-optical emission spectrometer (PerkinElmer model 7300 DV, Waltham, MA, USA) with a V-groove nebuliser, quartz-glass Scott spray chamber, and charge-coupled device (CCD) detector. RF generator power 1.55 kW, frequency 42 MHz; plasma gas flow 16 L/min; auxiliary gas flow 1.6 L/min; viewing height 5 mm above coil; nebuliser pressure 140 kPa; pump rate 2.5 mL/min. Simultaneous multi-element measurement of Pb, Cd, Cr, Ni, Zn, Cu.

Speciation. Total Pb, total Cd, total Cr (no hexavalent speciation), total Ni, total Zn, total Cu. No arsenic or mercury panel.

Quality assurance. Three certified reference materials were used to verify accuracy: NCS ZC 73008 Rice and NCS ZC 73009 Wheat (China National Analysis Center for Iron and Steel, Beijing) and SRM 1568b Rice flour (NIST, Gaithersburg, USA). Relative recoveries for the certified materials were 87.5-109 %. Standard-addition slopes compared to external-calibration slopes in SRM 1568b showed no matrix effect. LODs were calculated as 3·Sb/m from six replicate blank measurements; values fell between 0.1 and 0.35 μg/kg across the six metal channels. Reagents: HNO₃ (65 %, suprapur) and H₂O₂ (30 %) from Merck (Darmstadt, Germany); 1000 mg/L single-element metal standards from Sigma (St. Louis, USA); ultrapure water from a Milli-Q system (Millipore, Bedford, MA, USA). All plastic- and glassware was soaked in 2 M HNO₃ and rinsed with deionised water before use.

Risk assessment. EWIs were computed as EWI (mg/kg body weight per week) = C_cereal × WC_cereal / BW, with C_cereal the per-commodity mean concentration (mg/kg dry weight), WC_cereal a weekly cereal consumption of 770 g/week (110 g/day × 7) per the Institute of Standards and Industrial Research of Iran (2010), and BW a reference body weight of 60 kg. PTWI reference values were taken from Naseri et al. (2015) Table 4.

Statistical analysis. Descriptive statistics in Microsoft Excel 2010. One-way ANOVA, inter-metal correlations, and principal component analysis in SPSS v21.

Implications

This source contributes Iranian-market occurrence data for total Pb, Cd, Cr, Ni, Zn, and Cu in seven bulk-grain and pulse commodities sampled in 2014, plus a worked weekly-intake risk assessment under a defined consumption-and-body-weight assumption. Principal contributions to the wiki evidence pool:

• A consistent Pb signal across all seven Kermanshah-market commodities (means 0.95-1.90 mg/kg) that exceeds both the Codex Alimentarius 0.2 mg/kg cereal limit and the Iranian 0.15 mg/kg cereal limit by roughly an order of magnitude. The Pb signal is present in rice (1.35 mean), wheat (1.85), bean (1.90), and split peas (1.83) at very similar magnitudes despite the commodities being structurally and agronomically distinct, which is consistent with a Pb pathway that does not require direct soil uptake (e.g., post-harvest handling, storage, packaging, or the urban air-deposition pathway the authors cite for Kermanshah city). The paper does not isolate the pathway.
• A Cd signal at mean concentrations exceeding the Codex 0.1 mg/kg cereal limit in wheat (0.41), corn (0.29), bean (0.13), and split peas (0.15), with the wheat brand-range spanning 0.038-1.99 mg/kg — a 50-fold within-commodity spread. The corn within-commodity range (0.05-1.048 mg/kg) is similarly large. The Cd-in-pulses values fall in the same band as the Cd-in-rice values from this study (0.055) and from prior Iranian work (Mirlohi 2013, Naseri 2015 cited in the source).
• A Cr-in-cereals signal (means 0.48-0.75 mg/kg) within the range reported elsewhere for Iranian and Nigerian cereals; Cr was detected in 100 % of brand-samples. Speciation between Cr-III and Cr-VI is not addressed by the paper, and the wiki page therefore records this as total Cr only.
• A Ni signal that is below detection in roughly 6 % of rice brands but elevated in bean (mean 2.50 mg/kg, max 4.57 mg/kg in a white-bean brand) — a commodity-level pattern consistent with leguminous biological accumulation of Ni reported elsewhere.
• Zn and Cu values within ranges reported for cereals in Iran, Spain, Finland, and Nigeria; these are essential-mineral micronutrient contributions, not contamination findings.
• EWI estimates that remain below JECFA PTWIs across all 42 (commodity × metal) cells, with the bean Pb EWI (97 % of PTWI) and bean Ni EWI (92 % of PTWI) as the closest-to-ceiling values under a single-commodity assumption.

The single-city sampling footprint, the small per-cell replicate count (triplicate digestions per brand), and the absence of Pb / Cd / As / Hg speciation discipline place this source at the B-tier evidence level. It should pool with the parallel Ataee et al. 2016 ICP-OES-validation Kermanshah survey and other Iranian-market cereal-occurrence work (Naseri 2015, Mirlohi 2013, Heshmati 2020, Ataee 2016 — same authors’ group share between Pirsaheb and Ataee/Fattahi), not anchor any standalone characterisation. The 1.99 mg/kg Cd extremum in a single wheat brand-sample is a defensible “high tail” anchor if pooled-percentile work for Iranian-market wheat needs an upper-extreme reference.

Wiki pages this source may touch

• lead
• cadmium
• chromium
• nickel
• zinc
• copper
• rice
• wheat
• corn
• maize
• beans
• lentils
• legumes
• cereals
• rice-bulk-grain
• other-grain-products
• legumes-pulses-other

Verification notes

• Frontmatter discipline. All ingredient, product, metal, and jurisdiction slugs verified against the 2026-05-18 taxonomy snapshot. The matrix list captures the seven physical commodities (rice-grain, wheat-grain, corn-grain, peas, beans, lentil, split-peas) plus the umbrella cereal-grain matrix; ingredient routing is via the closed taxonomy (no peas or split-peas ingredient slug exists yet; auto-stub at freq-2 is the routing-layer’s job). The legumes and cereals umbrella ingredient slugs cover the routing fan-out for the pulse and grain commodities respectively.
• Cite-key choice. pirsaheb2015-iran-kermanshah-cereals-metals follows the descriptive-suffix convention (first author, year, country, region, commodity-group, analytes). The “metals” suffix is intentionally broad because the paper covers six analytes (Pb, Cd, Cr, Ni, Zn, Cu) and a more specific suffix would be unwieldy.
• Evidence tier B. Peer-reviewed in Food Additives & Contaminants: Part B (Taylor & Francis); method validated against three CRMs with recoveries 87.5-109 %; standard-addition checks for matrix effects passed. Sampling footprint is single-city (Kermanshah) with three samples per brand and 3-11 brands per commodity, n=150 packed samples total. The single-province scope and brand-level sampling structure are the dominant reasons for B rather than A.
• Speciation. Total metals only. No As or Hg panel. No Cr-VI speciation step — the metals: field uses Cr (total) per CLAUDE.md Part 14, not Cr-VI. Pb and Cd are total per the standard digestion-and-ICP-OES protocol; no chemical speciation between Pb species or Cd species was attempted.
• Brand firewall (Part 12, strict reading). The paper attributes its per-brand contamination extrema to specific cultivar and place-of-origin identifiers (a mix of Iranian rice and wheat cultivar names and producer-brand or town-of-origin tags; the paper does not consistently disambiguate which is which). Under the strict 2026-05-17 reading of Part 12, no brand-level or cultivar-level identifier was carried into the wiki page tables, narrative, or verification notes. Per-commodity means and ranges are reported aggregated across all brand-samples within each commodity type, as the paper itself does in Figures 1-2 and Table 3. The specific “1.99 mg/kg in a single wheat brand-sample” and “4.57 mg/kg in a single white-bean brand-sample” extremes are reported as commodity-level extremes without naming the cultivar or brand.
• Wiki/HMTc firewall (Part 2). No threshold proposals, no consumer-audience advisories, no synthesis claims against other papers beyond what the source itself cites. The Implications section reports what this paper contributes; cross-paper synthesis (e.g., updating ingredient contamination_profile blocks for rice, wheat, cereals, legumes) is the Part 9 workflow’s job.
• Reference-value attribution. The paper attributes the Pb 0.2 mg/kg and Cd 0.1 mg/kg cereal ceilings to “Codex Alimentarius” and cites Codex Standard 193-1995 (amended through 2012). The 0.15 mg/kg Pb and 0.06 mg/kg Cd cereal ceilings are attributed to ISIRI 12968 (Institute of Standards and Industrial Research of Iran, 2010, “Food and feed - maximum limit of heavy metals”, 1st ed., Tehran). These are reported as the paper attributes them; the wiki page does not extend the comparison to contemporaneous EU or FDA limits because the paper does not.
• Basis. All values are reported on a dry-weight basis as the paper describes (sample dried at 40 °C for 100 min, then dry-ashed at 500 °C for 11 h total). The EWI calculation in Table 3 uses these dry-weight concentrations against a weekly fresh-consumption mass of 770 g; this is a known basis mismatch in the paper itself (cooked / hydrated cereal mass is the actual consumption mass), and the EWI values inherit that limitation. The wiki page reports the EWI table as the paper publishes it without basis-conversion adjustment.
• Sampling year and replication. Sampling stated as “2014” in the Sample collection section. Per-commodity n (number of brands) ranges 3-11 per the methods text, with three ~50 g samples per brand; the paper does not publish the exact per-commodity brand count. Triplicate digestions per sample. Total packed-sample count is 150 across the seven commodities.
• Pb-range reporting. The paper publishes an explicit per-brand Pb range only for rice (0.99-2.3 mg/kg). For the other six commodities, only per-commodity means are reported. The “0.54-4.89 mg/kg in wheat” and similar ranges that appear in the prose are attributed by the authors to prior Iranian work (Mirlohi 2013, Zazoli 2010, Jahed Khaniki and Zazoli 2005), not to this study. The wiki page table accordingly carries Pb ranges only where the source publishes them.
• Data integrity. All values in the Key numbers section transcribed from Figures 1-2 (mean Pb and Cd bars), prose on pp. 3-5 (per-commodity means and Cd / Cr / Ni / Zn / Cu ranges), Table 2 (CRM accuracy), and Table 3 (EWI summary), and verified against the original PDF. No paper-internal contradictions identified.
• Audit-application notes (2026-06-01, Claude audit subagent, general-purpose, fresh context). Subagent verdict REVISE. Three findings applied: (1) opening narrative Cd-exceedance count corrected from “five of seven commodities (wheat, corn, bean, split peas)” to “four of seven commodities (wheat, corn, bean, split peas)” — the enumerated list was correct, the count was wrong (verified against source p. 4: “all cereals were higher than the safe limit… except for peas and lentil”; rice mean 0.055 was below Codex per p. 3, so Codex-exceeding commodities total 4); (2) opening narrative Iranian-limit framing corrected from “in all commodities except lentil where the Iranian limit was matched” to “in six of seven commodities (all commodities except rice, whose 0.055 mg/kg mean was below both ceilings)” — the prior phrasing both misattributed the below-Iranian-limit commodity (rice, not lentil) and used “matched” where the source describes lentil mean 0.07 as “higher than the safe limit as set by the National standards of Iran” (p. 4); (3) brand-firewall Verification note rewritten to describe the stripping policy without enumerating the cultivar/brand identifiers that were stripped (the audit correctly observed that listing the names in the Verification note re-introduces the brand-level information that the table-side stripping was meant to remove). No findings rejected; all three findings were verified against the source and applied.

Page history

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