Taher & Abojassim 2023 — Heavy metals in baby biscuits from Iraqi markets

Summary

This is a market-occurrence survey of toxic and essential metals in biscuit products marketed for infants and sold in Iraqi retail outlets. The authors measured zinc, lead, and cadmium by flame atomic absorption spectroscopy in 13 biscuit samples (codes B1–B13) of seven stated national origins, then computed dietary-exposure and health-risk indices for a baby consuming biscuits daily. For the Heavy Metal Index the load-bearing finding is cadmium: the mean Cd concentration (0.205 mg/kg dry weight) sits essentially at the FAO/WHO food limit of 0.2 mg/kg, and 7 of the 13 samples exceed it, while lead stays well below its 0.3 mg/kg limit in every sample and zinc stays far below its 9.4 mg/kg limit. The authors nonetheless conclude that aggregate health-risk parameters (Hazard Index, carcinogenic risk) remain inside US-EPA acceptable bands for all samples, because biscuits are a small fraction of total infant diet; they flag the Cd exceedances and long-term cumulative exposure as the residual concern. The paper is direct evidence on a baby-snack matrix and is most useful to the wiki as a cadmium data point for cereal/wheat-based infant biscuits, with the caveat that it is a single-region survey using flame AAS rather than ICP-MS.

Key numbers

Concentrations are reported by the source in mg/kg on a dry-weight basis (biscuits oven-dried and pulverized before digestion); ppb (µg/kg) conversions are added in brackets for wiki consistency. All values are total-metal by flame AAS.

• Concentration order across samples: Zn > Cd > Pb.
• Cadmium is the only analyte breaching its limit: the seven exceeding samples carry 0.201–0.267 mg/kg; the six compliant samples carry 0.119–0.196 mg/kg. The authors state 46% of samples (6 of 13) are at an “uncontaminated” level for Cd, i.e. 54% are above the limit.
• Health-risk indices (per the authors’ EDI/THQ/HI/CR model for an 18-month, daily-biscuit-consuming infant): mean Hazard Index 0.768 ± 0.040 (all samples < 1); mean carcinogenic risk 1.94 ± 0.25 × 10⁻⁶ (within the US-EPA 10⁻⁶–10⁻⁴ band). Cd dominates the Target Hazard Quotient (mean THQ_Cd 0.704) versus Pb (0.057) and Zn (0.006).
• Pearson correlations among the three metals are weak and non-significant (p > 0.05), so the authors infer no shared dominant contamination source across samples.

Methods (brief)

Flame atomic absorption spectroscopy (Buck Scientific 210 VGA), air/acetylene flame, at 213.9 nm (Zn), 283.2 nm (Pb), 228.9 nm (Cd). Wet acid digestion of 1 g dried, pulverized biscuit in HNO₃ then HClO₄. Calibration from metal-salt stock standards; deuterium background correction and the 210VGP variable pulse corrector used to limit interference. Only Zn, Pb, and Cd were determined; no arsenic, mercury, nickel, aluminium, chromium, or tin, and no speciation. Health-risk parameters (EDI, THQ, HI, CR) computed against US-EPA reference doses and a stated infant body weight and biscuit intake.

Implications

• Cadmium in cereal/wheat-based infant biscuits is the actionable signal: a mean at the FAO/WHO limit with a majority of samples over it, on a dry-weight basis, in a snack format aimed at 6–24-month-olds. This is consistent with the broader pattern that Cd tracks with cereal and root-derived ingredients in infant foods.
• Lead is low and compliant here (mean ≈66 ppb dry weight), which is a useful contrast point for the lead baseline in baked cereal snacks versus the higher Pb seen in some root-vegetable and rice-based infant products.
• Fitness caveat for synthesis: flame AAS has higher detection limits than ICP-MS, so the low Pb values especially should be weighted as B-quality for any pooled distribution even though the study design is A-tier. Single region (Iraq), single year (2023), n=13.

Wiki pages this source may touch

• cadmium — cereal/wheat infant-biscuit Cd occurrence, mean at the FAO/WHO limit.
• lead — low-Pb contrast point for baked cereal snacks.
• wheat-cereal-biscuits and wheat — Cd/Pb occurrence in the wheat-biscuit ingredient line.
• baby-food — baby-snack/biscuit format occurrence data.

Verification notes

• Concentrations taken from Table 2 (per-sample Zn/Pb/Cd) and the abstract/discussion means. The per-sample brand names and origins in Table 1 are withheld per the brand firewall (CLAUDE.md Part 12); only the category-level distribution and the set of stated national origins are reported here, not any brand-to-value mapping.
• Sample-count discrepancy: the Methods (“Collection Sample”) text states “Thirty samples of different types of biscuit samples” were collected, but Table 1 (sample identities/origins) and Table 2 (concentrations) both enumerate 13 sample codes (B1–B13). All reported statistics are computed over the 13 tabulated samples, so sample_n is recorded as 13; the “30” is treated as either total units collected before grouping into 13 product types or a transcription error. Flagged for any future re-read.
• Units are the source’s mg/kg dry weight; ppb conversions here are 1 mg/kg = 1000 µg/kg. Basis is dry weight (oven-dried, pulverized biscuit), not as-consumed.
• Speciation: total Pb and total Cd by flame AAS; no inorganic/organic speciation claimed and none inferred.
• Zinc is reported as an essential element for completeness and is not an HMI/HMTc target analyte; it is not routed to a metals page.

Page history

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