Al Zabadi et al. 2018 — Cd, Pb, Cu, and Zn in Palestinian canned foods

This study quantified cadmium, lead, copper, and zinc in 16 canned food samples — four products (beans, chickpeas, corn, mushroom) with four different brand-product combinations each — sold in a single supermarket in Nablus, Palestine, using flame atomic absorption spectrometry (FAAS, Thermo Scientific iCE-3000 series). Samples originated from Thailand, China, the United Arab Emirates, Jordan, and Palestine. Concentrations are reported in mg/L of the digestion solution (5 g sample digested into 50 mL final volume; on a wet-weight food basis this corresponds to a 10× multiplier into mg/kg). Cadmium and copper concentrations exceeded the authors’ stated permissible-limit references in multiple samples; lead exceeded its 1 mg/L reference in one canned corn sample; zinc was within the cited reference across the dataset.

Key numbers

Reported concentration ranges across all 16 samples (mg/L of digestion solution, abstract and discussion):

• Cadmium (Cd): 0.019–0.322 mg/L
• Lead (Pb): 0.089–1.17 mg/L
• Copper (Cu): 0.79–3.25 mg/L (Table 1 maxima; the abstract gives 0.79–3.97 mg/L and the discussion text states 0.79–2.97 mg/L — neither matches Table 1, see verification notes)
• Zinc (Zn): 2.058–10.66 mg/L

Average concentration by food type (mg/L ± SD, from Table 2):

Per-sample concentrations by country of origin (mg/L, from Table 1; brand identifiers omitted per Part 12):

Canned corn (n=4): Pb 0.30 (Thai), 0.47 (UAE), 0.50 (Chinese), 1.17 (Thai); Cd 0.01–0.09; Cu 0.79–1.05; Zn 5.49–6.80. One Thai-origin corn sample drove the Pb maximum of 1.17 mg/L — the only sample above the 1 mg/L permissible-limit reference the authors cite.

Canned chickpeas (n=4): Pb 0.12–0.75 (UAE, Jordanian, two Palestinian-origin); Cd 0.10–0.20; Cu 1.93–2.05; Zn 8.90–10.66. All four chickpea samples exceeded the authors’ 0.9 mg/L Cu reference.

Canned beans (n=4): Pb 0.089–0.35 (with two samples reported as “ND”); Cd 0.23–0.32; Cu 1.68–3.25; Zn 6.55–9.26. The Jordanian-origin sample had the highest Cd (0.322 mg/L); the UAE-origin sample had the highest Cu (3.25 mg/L). All beans samples exceeded the 0.9 mg/L Cu reference.

Canned mushroom (n=4, all Chinese origin): Pb 0.293–0.549; Cd 0–0.065 (two ND); Cu 0.815–1.438; Zn 2.058–5.670. All mushroom samples were Chinese-origin.

Permissible-limit references cited by the authors (all in mg/L as reported):

• Cd: 0.006 mg/L (cited as ATSDR chronic-oral MRL derivation)
• Pb: 1 mg/L (Joint FAO/WHO Codex maximum for canned food)
• Cu: 0.9 mg/L (RDA reference; framed by the authors as a permissible limit)
• Zn: 11 mg/L for males / 8 mg/L for females (RDA references; framed by the authors as permissible limits)

The authors compare their mg/L measurements directly to these reference values without unit reconciliation; see verification notes on the mg/L vs mg/kg basis question.

Methods

FAAS on a Thermo Scientific iCE-3000 series flame atomic absorption spectrometer (serial c113500021) with element-specific hollow cathode lamps for Cd, Pb, Cu, Zn. Wavelength, slit width, and lamp current followed manufacturer-recommended settings.

Sample preparation: 5 g of homogenized can contents transferred to a 100-mL flask, digested in a fume hood with ~5 mL concentrated HNO3 (Riedel-de Haën No. 30713), heated with a Bunsen burner until first vigorous reaction, then 2 mL H2SO4 (batch P110001671) added with continued heating and incremental HNO3 additions until the solution became clear yellow-orange with no solid residue (total 25–30 mL HNO3 over 1.5–2 h per sample). Digestate transferred to 50-mL volumetric flask, diluted to volume with distilled water.

Calibration: external five-point curves (0, 2, 5, 10, 20 mg/L) prepared from Pb(NO3)2 (1.598 g), cadmium salt (0.27 g), ZnSO4·7H2O (4.397 g), and Cu(NO3) salt (0.465 g) in deionized water to give 1000 mg/L stock; serial dilution to working standards. Calibration curves shown in Figures 1–4. Instrument re-zeroed with distilled water between samples.

Three replicate analyses per sample. The paper does not report LOD/LOQ values, recovery from spiked samples, or use of certified reference materials. No speciation performed: total Cd, Pb, Cu, Zn only.

Implications

Direct evidence on contamination of canned legumes, canned corn, and canned mushroom marketed in Palestine. The data reflect the imported supply chain (Thailand, China, UAE, Jordan dominate the sample frame; only chickpeas had Palestinian-origin samples). Useful for contributing-source synthesis on the canned-vegetables and legumes-pulses product pages. The mg/L-vs-mg/kg unit question (see verification notes) and the absence of LOD/LOQ reporting argue for caution before treating the highest reported values as definitive per-product wet-weight concentrations.

Wiki pages this source may touch

• beans
• legumes
• canned-corn
• canned-mushrooms
• canned-vegetables
• legumes-pulses-other
• cadmium
• lead
• copper
• zinc

Verification notes

• 2026-05-25 merge-enhance (Claude Code, autonomous ingest skill v2.0). The pre-existing version of this page (updated 2026-05-14) had multiple schema-era and content defects, all corrected in this pass:
  • raw_handle: manual-fetch-kimi (generic parent-folder placeholder) → MFK_p0315-environmental-exposure-assessment-of-cadmium per the v2 manual-fetch handle convention.
  • raw_path shortened to a non-existent stub P0315.pdf → corrected to the full filename present in the source folder.
  • metals: [Cd, Pb] → [Cd, Pb, Cu, Zn] (the paper’s analyte list is all four; the prior frontmatter omitted Cu and Zn even though they are central to the study).
  • ingredients had two invented slugs (canned-beans, chickpeas) that do not exist in the current taxonomy. Replaced with the canonical beans and legumes umbrella slugs; kept canned-corn and canned-mushrooms which do exist.
  • products: [canned-foods] referenced a non-existent slug. Replaced with canned-vegetables (covers canned corn, canned mushroom; the conventional umbrella for non-fruit non-fish canned plant foods in the current taxonomy) and legumes-pulses-other (covers canned beans and chickpeas as a legumes product).
  • Added no_doi_assigned: false, access_url, and raw_sha256 fields (absent in prior version).
  • Expanded sample_population to capture the per-product origin spread and the triplicate-replicate structure.
• Legacy heading removed. Prior section ## Wiki pages updated on ingest (Part 5b system-rule violation: the model does not maintain routing by hand) replaced with the current ## Wiki pages this source may touch form.
• Brand firewall (Part 12, strict reading locked 2026-05-17). The source PDF names brand identifiers extensively (Table 1 lists per-sample brand names alongside country of origin). The prior wiki page leaked several of these into the body (“Kaseeh” canned beans, “Americana” chickpeas, “marina corn”, “Delmonaty” beans). All brand identifiers stripped in this pass; country of origin retained because it is a format-relevant supply-chain descriptor, not a brand ranking. Method-section vendor names (Thermo Scientific iCE-3000, Riedel-de Haën reagent) retained per the 2026-05-17 method-vendor exception.
• Wiki/HMTc firewall (Part 2). Prior Implications section contained certification-facing guidance (“this source should be used with caution as a secondary reference”; “heavier reliance on sources with explicit mg/kg reporting and validated LODs is recommended”), course-facing language, and app-facing risk advisories. All deleted; the new Implications section reports what the data are useful for (synthesis input) and flags the unit-basis caveat as a methodological observation, without proposing HMTc thresholds or consumer translations.
• Paper-internal Cu-range discrepancy (typesetting, not data-integrity). The abstract gives Cu range 0.79–3.97 mg/L; the discussion paragraph on page 3 gives 0.79–2.97 mg/L; Table 1 maximum Cu value is 3.25 mg/L (UAE-origin canned beans). Both the abstract and discussion text appear to be transcription errors; Table 1 is authoritative. The Key numbers section reports 0.79–3.25 mg/L as observed from the table and footnotes the prose-text discrepancy.
• Cd reverse-engineered mg/kg estimate withdrawn. The prior page asserted that on a mg/kg-food basis the highest Cd (0.322 mg/L × 10 = 3.22 mg/kg) “would indicate severe contamination that far exceeds any known regulatory limit.” The 5 g → 50 mL dilution factor is correct, but the paper itself reports throughout in mg/L without performing this conversion, and the abstract/conclusion frame the result against mg/L permissible-limit references. The mg/L-vs-mg/kg reconciliation belongs in Part 9 synthesis on the relevant ingredient and product pages, not in this source page. The mg/L value is reported here as the paper reports it; the basis caveat is flagged.
• Speciation. No speciation performed; total Cd, Pb, Cu, Zn only. Frontmatter uses unspeciated metal symbols accordingly.
• LOD/LOQ. Not reported in the paper. Two mushroom Cd values and two bean Pb values are listed as “ND” in Table 1; the practical detection floor is not stated.
• Sample-size limitation. n=16 (4 per product type) from a single supermarket on a single occasion. The authors acknowledge this as a baseline study limitation; treat reported ranges as indicative rather than representative of the Palestinian canned-food supply chain.

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.