Investigation of heavy metal concentrations and determination of estimated daily intake and health risk index infant formula and baby foods in Zahedan in 2020

Overview

This Sigma Journal of Engineering and Natural Sciences paper from Zahedan University of Medical Sciences measured Pb and Cd in 18 brands of powdered infant milk formula and 7 brands of infant cereals / baby foods collected from the Zahedan market (Sistan and Baluchestan Province, southeastern Iran) in March-April 2019. Pb and Cd were quantified by graphite-furnace atomic absorption spectroscopy on dry-ashed samples. Estimated Daily Intake (EDI) and Health Risk Index (HRI) were computed for two infant age strata (0-6 months and 6-12 months) using daily-consumption assumptions of 200 g/day at 6.5 kg body weight and 100 g/day at 10 kg body weight, respectively, drawn from manufacturer feeding tables. Although the article carries a 2024 publication date, the field sampling and laboratory work were conducted in 2019-2020; the authors describe the work as a 2020 Zahedan-market survey.

Key numbers

Concentrations are reported on the as-sampled basis of each product (dry powder for infant formula; dry cereal for infant cereals). All values µg/kg unless otherwise noted; the paper variously reports ng/g (equivalent to µg/kg) and mg/kg; converted to µg/kg below.

Lead (Pb) — Table 1, p. 616:

• Infant milk formula (n = 18): mean 14.7 ± 0.98 µg/kg; detection frequency 100%
• Infant cereals (n = 7): mean 13.77 ± 1.51 µg/kg; detection frequency 100%
• Outlier infant-formula samples flagged as exceeding the Iranian/Codex 10 µg/kg permissible level with statistical significance (p < 0.05): sample no. 2 = 49.73 ± 0.85 µg/kg and sample no. 9 = 45.27 ± 3.27 µg/kg
• Range across remaining infant-formula samples: 5.92 to 16.78 µg/kg
• Range across infant-cereal samples: 8.51 to 18.16 µg/kg

Cadmium (Cd) — Table 1, p. 616:

• Infant milk formula (n = 18): mean 0.097 ± 0.016 µg/kg; detected in 22% of samples (4/18 brands); positive-sample values 0.11, 0.22, 0.24, 1.19 µg/kg (highest in sample no. 4)
• Infant cereals (n = 7): mean 0.705 ± 0.12 µg/kg; detected in 57% of samples (4/7 brands); positive-sample values 0.26, 1.32, 1.74, 1.80 µg/kg (highest in sample no. 5)

Comparison with literature (Table 2, p. 616): Authors place their Zahedan results within the lower-to-mid range of reported Pb and Cd in infant formula across Ethiopia (Pb ND-0.103 mg/kg, Cd ND), Nigeria (Pb 0.08-0.23 mg/kg, Cd 0.05-0.4 mg/kg), Pakistan (Pb 0.0287-0.097 mg/kg, Cd 0.0042-0.0123 mg/kg), Kenya (Pb 0.018-0.059 mg/kg, Cd ND), EU market (Pb 0.0082-0.043 mg/kg, Cd 0.00033-0.00045 mg/kg), and Turkey (Pb 0.00375-0.0249 mg/kg, Cd ND-0.00749 mg/kg).

Exposure and risk — Table 3, p. 618:

• Highest EDI for Pb in infant formula at 0-6 months: 0.226 µg/kg·day·bw (below the cited TDI of 1.8 µg/kg·day·bw); at 6-12 months: 0.147 µg/kg·day·bw
• EDI for Pb in infant cereals at 0-6 months: 0.211; at 6-12 months: 0.137 µg/kg·day·bw
• EDI for Cd in infant formula at 0-6 months: 0.001 µg/kg·day·bw; in infant cereals at 0-6 months: 0.01 µg/kg·day·bw
• HRI computed against safe-limit denominators reported in the paper: all sample-mean HRIs < 1 across both age strata for both Pb and Cd (Pb HRI range 0.038-0.12; Cd HRI range 0.09-0.7 as printed, with the Cd-cereals-6-12mo value of 0.7 in Table 3 appearing inconsistent with the rest of the row and likely a print-error — the authors’ conclusion that all HRI < 1 at mean exposure is consistent with the EDI values shown)

Regulatory standards cited by the authors:

• Codex CXS 193-2009 / Iranian standard for Pb in infant formula: 10 µg/kg
• Codex / Iranian standard for Pb in baby food: 20 µg/kg
• Authors state Codex Cd limit for infant formula is “zero” (as quoted on p. 615); they also cite a “Codex standard” for Cd in conventional liquid milk of 10 µg/L (p. 616)
• LOD: Pb = 8 µg/kg (0.008 mg/kg); Cd = 9.6 µg/kg (0.0096 mg/kg)
• Matrix-spike recovery: 95.5-104.6%; five-point calibration r² = 0.998-0.9996

Methods (brief)

Sampling: census of 18 best-selling powdered infant milk-formula brands and 7 baby-food / infant-cereal brands from Zahedan supermarkets between March and April 2019; products intended for infants 6 months to 1 year; metal sample containers preserved.

Digestion: ~5 g of each product weighed into acid-washed crucibles; dry-ashed in an electric kiln (Nabertherm, Germany) by ramping to 500 °C and holding 8 h; ash dissolved in 10 mL of 6 M HCl on a 100 °C heater for 1 h to dryness; reconstituted in 10 mL of 0.1 M HNO3.

Quantification: graphite-furnace atomic absorption spectroscopy on a PerkinElmer A Analyst 700; analytical-grade reagents (Merck, Germany); 1000 mg/L Pb and Cd standards; five-point calibration curve (r² 0.998-0.9996); matrix-spike recovery 95.5-104.6%; LOD computed as 3 × pooled SD of six blank runs.

Only total Pb and total Cd were quantified; no speciation, no As, Hg, Al, Ni, or other metals.

Exposure assessment: EDI = (concentration × daily consumption) / body weight, with manufacturer-suggested daily consumption of 200 g/day at 6 months (body weight 6.5 kg) and 100 g/day at 7-12 months (body weight 10 kg). HRI computed as mean daily intake divided by the safe-limit value for each metal. Statistical analysis: one-way ANOVA + Tukey post-hoc at 95% confidence (SPSS v20).

Implications

This paper contributes Pb and Cd occurrence data for two product categories — powdered infant milk formula and infant cereals — in the Iranian market (Sistan and Baluchestan Province), useful for the Infant Formula Powder and Infant Cereal product-page synthesis passes. The 100% detection frequency for Pb across both product categories and the two outlier infant-formula brands at ~45-50 µg/kg are the most notable findings. The narrow Pb-Cd analyte scope (no As, Hg, Al, Ni speciation) limits the paper’s contribution to single-metal occurrence rows.

The authors’ regulatory framing compares the sample-mean EDI against Codex TDI/PTWI rather than comparing per-sample Pb concentrations against the Codex 10 µg/kg product-level maximum for infant formula; this is the authors’ analytical choice, not a wiki-side claim.

Verification notes

• 2026-05-17 merge-enhance pass (automated editorial review, manual-fetch ingest cycle): predecessor page (updated 2026-05-13) had the following defects, all fixed in this revision:
  • raw_handle: manual-fetch-source-retrieval (legacy placeholder) → MFK_investigation-heavy-metals-infant-formula-zahedan
  • raw_path truncated to Investigation of heavy metal concentrations and health risk .pdf → full filename Investigation of heavy metal concentrations and health risk assessment in infant formula and infant cereals in Zahedan, Iran.pdf
  • matrices contained the non-vocabulary slug wet-weight (basis is not a matrix); removed. Native basis (as-sampled dry powder / dry cereal) clarified in body.
  • products: [[products/baby-cereals-dry-rice-based]] was an invented/overspecified slug — the paper does not characterize the cereal samples as rice-based vs non-rice and reports them generically as “baby food” / “infant cereals”. Routed to the umbrella [[products/infant-cereal]] instead, per Part 5b broad-scope rule.
  • ingredients: cereals (generic) → [[ingredients/infant-cereal-ingredients]] for precision.
  • ## Implications previously contained Part 2 wiki/HMTc-firewall violations (“HMT&C comparison should note that…”) and consumer-audience translations (“Geographic origin matters; sourcing from Sistan and Baluchestan should be flagged as a higher-Pb region”). Both removed; replaced with neutral occurrence-data framing.
  • ## Wiki pages updated on ingest legacy heading removed (superseded by routing audit).
• The paper publication year (2024) reflects the journal volume; underlying field/lab work was 2019-2020. Both dates are stated up front in the page intro.
• The Cd-cereals HRI value of 0.7 at 6-12 months in Table 3 (p. 618) is internally inconsistent with the other HRI cells (all 0.04-0.12) and with the corresponding EDI of 0.007 µg/kg·day·bw shown in the same column; treated here as a probable print-error and flagged in Key numbers rather than propagated as a contamination signal.
• Authors’ citation of the “Codex standard” for cadmium as “zero” (p. 615) does not correspond to any active Codex CXS 193-2009 maximum level for cadmium in infant formula. The wiki page reports the authors’ framing without endorsing the underlying claim; downstream regulation-page synthesis should use the regulation pages, not this paper, as the source of record for Codex Cd limits.
• 2026-05-17 audit editorial review (general-purpose, Phase 2 of /ingest-next-manual-fetch-pdf) returned REVISE with one ❌ on Check 2, asserting that [[ingredients/infant-cereal-ingredients]] was not in the taxonomy snapshot. Verified against the linked reference record (exists) and the editorial record (slug present in the Ingredients line). Finding is a false positive — the editorial review’s snapshot scan missed the entry. No change applied. All ⚠️ items in Check 1 were re-verified against Tables 1-3 (pp. 617-618) and confirmed correct. Effective verdict: PROMOTE.

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