Abdolahpour Alamdari et al. 2023 — Heavy metals in vegetables from Babol, Iran

This cross-sectional descriptive study measured copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in eight vegetable types grown in Babol city, Mazandaran Province, northern Iran during the 2021 harvest season. The highest mean Pb (0.5 mg/kg fresh weight) and Cd (0.06 mg/kg fresh weight) in Table 1 were both in parsley, with spinach and basil close behind, consistent with leafy vegetables accumulating more heavy metals than root vegetables or fruit vegetables. All hazard quotients (HQ) for Pb and Cd were below 1; Zn HQ exceeded 1 for parsley and spinach. Pb concentrations in parsley (0.5 mg/kg), spinach (0.48 mg/kg), and basil (0.16 mg/kg) exceeded the Iran National Standard Pb limit for leafy vegetables (0.2 mg/kg); Cd in parsley (0.06 mg/kg) and basil (0.032 mg/kg) exceeded the Iran Cd limit for leafy vegetables (0.05 mg/kg for leafy), while spinach Cd (0.04 mg/kg) was just below. Root and fruit vegetables met both standards. Sample size is small (n=4 per vegetable type, n=32 total), and the study covers a single agricultural area in northern Iran.

Key numbers

• Sample: 32 samples across 8 vegetable types (parsley, spinach, basil, tomatoes, cucumbers, potatoes, onions, beans); 4 samples per type; fresh-weight basis (concentrations converted from dry weight via per-vegetable dry-matter determination at 105°C for 24 h).
• Method: Atomic absorption spectrometry (model Avanta-P, GBC, Australia) after acid digestion of 1 g dry sample in 15 mL of HNO3 (70%) / HClO4 (65%) / H2SO4 (70%) (1:1:5) at 80°C; digestate diluted to 50 mL with distilled water.
• Mean Cu (mg/kg fresh weight, Table 1): parsley 6.67 ± 0.3, spinach 5.42 ± 0.34, potatoes 1.7 ± 0.55, onions 1.06 ± 0.30, basil 2.46 ± 0.34, tomatoes 1.36 ± 0.20, cucumbers 3.86 ± 0.65, beans 2.86 ± 0.65.
• Mean Zn (mg/kg fresh weight, Table 1): parsley 68.67 ± 3.33, spinach 63.31 ± 3.2, potatoes 15.73 ± 1.79, onions 14.3 ± 1.74, basil 32.39 ± 3.33, tomatoes 16.68 ± 0.70, cucumbers 51.21 ± 5.22, beans 58.21 ± 5.22.
• Mean Cd (mg/kg fresh weight, Table 1): parsley 0.06 ± 0.04, spinach 0.04 ± 0.44, potatoes 0.03 ± 0.01, onions 0.01 ± 0.08, basil 0.032 ± 0.04, tomatoes 0.027 ± 0.022, cucumbers 0.02 ± 0.36, beans 0.01 ± 0.39. Several reported SDs (spinach, cucumbers, beans) are an order of magnitude larger than the mean and likely contain a printing error in the original table; means are preserved as reported.
• Mean Pb (mg/kg fresh weight, Table 1): parsley 0.5 ± 0.16, spinach 0.48 ± 0.16, potatoes 0.20 ± 0.18, onions 0.18 ± 0.05, basil 0.16 ± 0.16, tomatoes 0.19 ± 0.43, cucumbers 0.088 ± 0.52, beans 0.067 ± 0.52. Tomatoes/cucumbers/beans SDs again exceed means, presumed printing errors in the original table.
• EDI (mg/kg/day, Table 2) for Pb: parsley 0.00021, spinach 0.0022, potatoes 0.0009, onions 0.0008, basil 0.0009, tomatoes 0.0009, cucumbers 0.00049, beans 0.0003. Highest Pb intake: spinach 0.0022 mg/kg/day.
• EDI (mg/kg/day, Table 2) for Cd: parsley 0.0001, spinach 0.0006, potatoes 0.0002 (first “Potatoes” row), onions 0.0001, basil 0.0006, second “Potatoes” row 0.00011 (almost certainly mislabeled Tomatoes — Tomatoes is missing from Table 2 despite being in Table 1, and the 0.00041 Cu / 0.078 Zn / 0.00011 Cd / 0.0009 Pb values in that second row plausibly belong to tomatoes given Table 1 concentrations), cucumbers 0.00009, beans 0.00006. Highest Cd intake: basil and spinach 0.0006 mg/kg/day.
• Hazard quotient sums (HI) across 4 metals (Figure 2, visually estimated): parsley ≈ 2.2, spinach ≈ 1.95, potatoes ≈ 0.7, onions ≈ 0.55, basil ≈ 0.95, tomatoes ≈ 0.7, cucumbers ≈ 1.1, beans ≈ 1.15. HI > 1 for parsley, spinach, cucumbers, and beans, with Zn the dominant contributor in every case. Zn individual HQ exceeds 1 for parsley (0.33/0.3 = 1.10) and spinach (0.341/0.3 = 1.14) only; for cucumbers (Zn HQ 0.83) and beans (Zn HQ 0.93), HI exceeds 1 because Zn-plus-other contributions sum above 1, not because Zn alone does. Pb and Cd individual HQs are below 1 in every vegetable.
• Reference doses used (RfD, mg/kg/day): Pb 0.0035, Cd 0.001, Cu 0.1, Zn 0.3.
• Iran National Standards (Institute of Standards and Industrial Research of Iran, No. 12968, 2010, per source p. 119): Pb 0.2 mg/kg in parsley/spinach/beans, 0.1 mg/kg in potatoes/onions/tomatoes/cucumbers; Cd 0.05 mg/kg leafy / 0.1 mg/kg tubers. WHO Pb maximum 0.3 mg/kg fresh weight.
• Compliance vs Iran standard: parsley Pb 0.5 > 0.2 (exceeds), spinach Pb 0.48 > 0.2 (exceeds), basil Pb 0.16 (basil not separately classified by the source; below both 0.1 and 0.2 thresholds), potatoes Pb 0.20 > 0.1 (exceeds), onions Pb 0.18 > 0.1 (exceeds), tomatoes Pb 0.19 > 0.1 (exceeds), cucumbers Pb 0.088 < 0.1 (compliant), beans Pb 0.067 < 0.2 (compliant). Parsley Cd 0.06 > 0.05 (exceeds leafy limit), basil Cd 0.032 < 0.05 (compliant), spinach Cd 0.04 < 0.05 (compliant), all others below limits.

Abstract/Table discrepancies (paper-internal)

• Abstract reports “the highest mean concentration of copper, zinc, cadmium and lead in tested samples was 12.86, 68.67, 1.93, and 0.48 mg/kg fresh weight, respectively, which found in parsley and spinach samples.” The 68.67 Zn and 0.48 Pb values are present in Table 1 (parsley Zn, spinach Pb), but 12.86 Cu and 1.93 Cd do not match any Table 1 cell. Discussion text states “The highest concentration of copper was related to beans with an average of 12.68 mg/kg fresh weight,” but Table 1 shows beans Cu = 2.86 mg/kg. The 12.86/12.68/1.93 figures appear to be either dataset maxima the paper did not tabulate or transcription errors in the abstract and discussion. Table 1 values are internally consistent and are used here as the citable means.
• Results-text values for parsley (“6.63±0.3, 68.67±33.3, 0.06±0.04, and 0.06±0.04 0.5±0.16”) contain a Cu mean (6.63) that differs from Table 1 (6.67), a Zn SD (33.3) that differs from Table 1 (3.33), and a duplicated Cd token followed by the Pb value with no separator. Table 1 values are preserved.
• Discussion claims “the lowest concentration was associated with onion products (1.06 mg/kg fresh weight)” for Cu, which is consistent with Table 1.

Methods (brief)

Descriptive cross-sectional study. Babol County, Mazandaran Province, Iran (40°36′–36°35′ N, 33°52′–43°51′ E; 1578 km², urban pop. 230,973; mean annual temperature 15.9 °C, rainfall 525.6 mm, humidity 78%). Seven vegetable types named in Methods (parsley, spinach, basil, tomatoes, cucumbers, potatoes, onions, beans — eight types are analyzed; the “7 types” Methods statement is inconsistent with the 8-row Table 1). 4 random samples per vegetable type were collected at harvest maturity in 2021 from the beginning, middle, and end portions of each field; 21 main-vegetable samples are also referenced in Methods. Edible parts washed with distilled water, oven-dried at 60–65 °C, crushed in an electric mill. 1 g crushed sample digested in 15 mL of HNO3/HClO4/H2SO4 (1:1:5) at 80 °C; digestate diluted to 50 mL. Concentrations measured by AAS (Avanta-P, GBC, Australia). Dry-matter fraction determined separately on triplicate fresh samples dried at 105 °C for 24 h to convert dry-weight measurements to fresh-weight basis. EDI calculated for 70 kg adult body weight; HQ = EDI / RfD with RfD values Pb 0.0035, Cd 0.001, Cu 0.1, Zn 0.3 mg/kg/day; HI = ΣHQ across the four metals. SPSS v16.0 for statistical analysis. Ethics approval: Tehran University of Medical Science (IR.Bmsu.rec1396.004). Note: the paper does not separate inorganic vs total arsenic or methylmercury vs total mercury; neither Hg nor As is measured.

Implications

Certification: Pb and Cd values for leafy vegetables from Babol exceed Iranian national standards in two of three leafy types tested (Pb in parsley and spinach above the 0.2 mg/kg parsley/spinach/beans limit; Cd in parsley above the 0.05 mg/kg leafy limit). Pb also exceeds the 0.1 mg/kg non-leafy limit in potatoes, onions, and tomatoes. Sample sizes are very small (n=4 per type) and the study area is a single agricultural plain in northern Iran with documented industrial and irrigation pressure. Values contribute occurrence data for vegetable categories grown around industrial or wastewater-irrigated areas in Iran; they should not be extrapolated to global leafy-vegetable baselines.

Courses: Useful as a worked example of how (a) fresh-weight vs dry-weight conversion matters for cross-study comparison, (b) HI summed across analytes can exceed 1 even when individual HQs for the toxic-priority metals (Pb, Cd) are well below 1 (because nutrient-essential metals like Zn dominate the sum), and (c) leafy vegetables can exceed regulatory limits for Pb and Cd while having no acute-toxicity HQ flag. Also illustrates documentation of abstract-vs-table discrepancies as part of good-faith literature reading.

App: Use Table 1 values for Pb, Cd, Cu, and Zn by vegetable type. Flag the abstract/results/discussion vs Table 1 discrepancies for Cu (12.86 / 12.68 / 6.67), Cd peak (1.93 in abstract not in table), and parsley Cu (6.63 in results text vs 6.67 in Table 1). n=4 per type is a low-confidence basis for any contamination-profile cell; mark confidence as low and weight by Iran-specific applicability.

Microbiome: Not applicable.

Verification notes

• 2026-05-20 merge-enhance: page predates the 2026-05-14 schema cut-off. Corrections applied to bring frontmatter in line with current convention and to expand the Key numbers section to cover all four measured metals (the prior version dropped Cu and Zn). Specific changes:
  • raw_handle corrected from generic manual-fetch-kimi to MFK_the-health-risk-assessment-of-heavy-metals-in-vege (matches the imongben2026/clair-caliot2021 MFK_ pattern in this folder).
  • raw_path filename corrected from truncated “…Vegetables Cultivat.pdf” to the full PDF name “…Vegetables Cultivated in Babol City, Iran.pdf”.
  • metals: expanded from [Pb, Cd] to [Pb, Cd, Cu, Zn]. The paper measures all four; the wiki should record all four even though only Pb and Cd are HMTc priority analytes.
  • Key numbers expanded to include full Cu and Zn means and SDs per Table 1, EDI values per Table 2 for all eight vegetables, and a per-vegetable Iran-standard compliance check.
  • Added explicit “Abstract/Table discrepancies” section. The prior page noted the Cd-peak abstract/table mismatch in a single Key-numbers bullet; the discrepancies are broader (Cu abstract 12.86 vs Table 1 max 6.67, Cu discussion 12.68 vs Table 1 beans 2.86, parsley Cu 6.63 results-text vs 6.67 Table 1, Zn SD 33.3 results-text vs 3.33 Table 1) and warrant their own section.
  • Updated updated: from 2026-05-13 to 2026-05-20.
  • products: [] retained per current vegetable-paper convention (chiutula2025, katebe2024, imongben2026, clair-caliot2021 all products: []; the routing layer falls back to broad scope, and none of the matrix slugs used here are in data/evidence/matrix-to-product-map.json, so the page passes audit-routing-discipline). The build-routing-audit advisory row for this source is informational, not blocking.
  • matrices: [leafy-vegetable, root-vegetable, legume] retained as-written; these slugs are used consistently across the vegetable-paper subcorpus even though they are not the leaf-product-page slugs (leafy-vegetables-other, root-tuber-vegetables, legumes-pulses-other). Renaming would be a corpus-wide migration, not a per-paper edit.
  • cite_key, doi, access_url, license, sample_n, sample_population, ingredient wikilinks, and jurisdictions preserved.
• 2026-05-20 audit-application (subagent verdict REVISE; five findings, four applied, one rejected, none confirmed false positive):
  • Applied: ingredients/tomatoes → ingredients/tomato. Verified taxonomy snapshot and wiki/ingredients/ directly — tomato.md exists, tomatoes.md does not. Invented-slug correction.
  • Applied: Iran Pb standard rewrite — auditor caught that source p. 119 puts beans in the 0.2 mg/kg parsley/spinach/beans bucket, not the 0.1 mg/kg bucket. Re-quoted source: “the allowable limit of lead concentration in parsley, spinach and beans is estimated 0.2 and in potatoes, onions, tomatoes and cucumber was estimated to be 0.1.” Reformatted the Iran-standards summary and the per-vegetable compliance line accordingly.
  • Applied: Garbled potatoes Pb compliance line “potatoes Pb 0.20 = 0.2 (at limit for non-leafy 0.1 — exceeds)” replaced with the clean “potatoes Pb 0.20 > 0.1 (exceeds)” framing.
  • Applied: Removed the Codex/FAO 10 mg/kg Cu advisory-benchmark sentence and the forward-looking “where Cu becomes a covered analyte” framing from Implications. Verified against source — the paper says only “the average concentration of copper in all analyzed products was lower than the FAO/WHO” without quoting a specific Cu limit, so the 10 mg/kg figure was imported from outside knowledge (Part 2 firewall slip).
  • Applied: Table 2 “second Potatoes row” clarified as almost-certainly-mislabeled Tomatoes (Tomatoes is missing from Table 2 despite being in Table 1; the second row’s values fit Table 1’s tomato concentrations).
  • Applied: Zn HQ vs HI conflation tightened — Zn HQ exceeds 1 strictly for parsley (1.10) and spinach (1.14); for cucumbers (Zn HQ 0.83) and beans (Zn HQ 0.93), HI > 1 is because Zn-plus-other contributions sum above 1, not because Zn alone does.
  • Noted, not changed: ingredients/basil is not in the taxonomy snapshot; basil cannot be added to frontmatter without first creating a basil ingredient page. Out of scope per CLAUDE.md (no new ingredient pages created during ingest; auto-stub handles ingredients ≥freq-2 separately).

Wiki pages updated on ingest

• leafy-vegetables
• spinach
• parsley
• root-vegetables
• potatoes
• lead
• cadmium
• copper
• zinc

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.