Rahati et al. 2026 — Heavy Metals in Infant Formula and Baby Food, Iran
This 2026 study from Mashhad University of Medical Sciences measures trace element concentrations in 80 infant formula and 27 baby food samples from the Iranian market, then applies deterministic and probabilistic (Monte Carlo, 10,000 iterations, 95th percentile) health risk assessment covering non-carcinogenic hazard indices (HI) and carcinogenic risk (CR) for infants aged 0–24 months. All HI values exceeded the EPA safety threshold of 1.0 for all age groups, driven principally by chromium and iron in formula and chromium and zinc in baby food. Lead, cadmium, and mercury were below the instrument LOD in all samples.
Key numbers
Instrument: ICP-OES (Spectro Arcoes-76004555); acid digestion with HNO3/HCl; recovery 80.46–100.55%. LOD values: Fe 0.06 mg/kg, Cu 0.2 mg/kg, Cr 0.14 mg/kg, Zn 0.02 mg/kg, Al 0.44 mg/kg, Cd 0.03 mg/kg, Co 0.012 mg/kg, Hg 0.0014 mg/kg, Pb 0.01 mg/kg, Se 0.11 mg/kg, Ba 0.13 mg/kg. All concentrations in mg/kg dry weight.
Pb: below LOD (0.01 mg/kg) in all 80 formula and 27 baby food samples across all three sampling periods.
Cd: below LOD (0.03 mg/kg) in all 80 formula and 27 baby food samples.
Hg: below LOD (0.0014 mg/kg) in all samples.
Al (infant formula): total mean 1.0 ± 1.4 mg/kg (Mashhad market, n=80); significant seasonal variation (p=0.034, higher in wet season). FAO/WHO ML for infant formula is 1 mg/kg; mean Al in formula exceeded this limit.
Cr (infant formula, total mean): 0.5 ± 0.8 mg/kg (n=80); significant seasonal variation (p=0.016). The JECFA Codex ML for Cr in infant formula is 0.001–0.0001 mg/kg (for children). Mean total Cr in this study exceeded that limit by multiple orders of magnitude; however, the paper measures total chromium by ICP-OES, not Cr-VI specifically.
Zn (infant formula total mean): 44.12 ± 2.4 mg/kg; FAO/WHO ML is 7 mg/day (exposure-based, not concentration-based, so direct comparison is not straightforward).
Fe (infant formula total mean): 82.96 ± 4.7 mg/kg.
Co (infant formula, total mean): 0.08 ± 0.1 mg/kg.
Se (infant formula, total mean): 0.4 ± 0.2 mg/kg.
Sr (infant formula, total mean): 2.8 ± 1.5 mg/kg.
Ba (infant formula, total mean): 0.2 ± 0.1 mg/kg.
Baby food means (n=27, total across age groups): Al 2.6 ± 1.6 mg/kg, Cr 2.3 ± 1.2 mg/kg, Cu 5.9 ± 9.5 mg/kg, Mn 5.9 ± 9.8 mg/kg, Se 2.3 ± 1.1 mg/kg, Sr 2.3 ± 1.1 mg/kg, Zn 54.15 ± 3.1 mg/kg, Fe 78.27 ± 7.2 mg/kg. Baby food Cr was significantly higher in wet season (p=0.003); Cu and Fe also showed significant temporal variation.
Non-carcinogenic HI (infant formula, deterministic): 3.54–3.92 across age groups (mean 3.70), driven principally by Cr (mean HQ=0.95), Fe (0.86), Zn (0.74), Se (0.54), Cu (0.41), Co (0.06), Mn (0.06), Al (0.00). All HI values exceed the EPA threshold of 1.0.
Non-carcinogenic HI (baby food, deterministic): 3.73–3.97 across age groups (mean 3.82), driven by Cr (0.84), Zn (0.94), Cu (0.66), Fe (0.58).
Probabilistic HI (95th percentile, infant formula): 2.17–5.05 depending on age group.
Probabilistic HI (95th percentile, baby food): 2.55–6.29 depending on age group.
Carcinogenic risk (CR) via Cr (infant formula): mean 9.55 × 10⁻⁵; range by age group 3.30 × 10⁻⁵ to 3.75 × 10⁻⁴. CR for Pb, Cd, and Hg not assessed because concentrations were below LOD.
Carcinogenic risk (CR) via Cr (baby food): mean 7.08 × 10⁻⁵; range 3.30 × 10⁻⁵ to 1.30 × 10⁻⁴.
Probabilistic CR (95th percentile, infant formula): 6.86 × 10⁻⁶ to 5.77 × 10⁻⁴.
Probabilistic CR (95th percentile, baby food): 1.34 × 10⁻⁵ to 1.55 × 10⁻⁴.
Sensitivity analysis: Cr concentration drove more than 97% of carcinogenic risk variance in both formula and baby food. Fe and Cr concentrations drove 27–33.7% of non-carcinogenic risk in formula; Cr and Zn drove 27.2–38.5% in baby food.
Methods (brief)
Cross-sectional market survey, three seasonal collection rounds (two dry season, one wet season), Mashhad retail. Acid digestion: 1 g sample + HNO3 + HCl, Bain-Marie indirect heating, 24 h ambient, then 90 °C for 2 h, filtered through Whatman grade-42. ICP-OES (Spectro Arcoes-76004555). Recovery 80.46–100.55% (acceptable range 80–101%). Risk assessment followed USEPA framework: EDI calculated from IR (age-group specific from USEPA), BW, EF, ED, AT. Cancer slope factors (OSF) used for Cr (respiratory route CSF applied as surrogate for oral, a noted limitation), Pb, Cd. Monte Carlo simulation via Crystal Ball v11.1, 10,000 iterations. Limitation: CSF for Cr oral route not established; authors used respiratory CSF, so cancer risk estimates for Cr carry substantial uncertainty. All HI and CR values are reported for the as-sold dry-weight matrix.
Implications
Certification: Demonstrates that Cr (total) and Fe concentrations in Iranian market infant formula consistently exceed FAO/WHO limits; Al also exceeds ML in formula. However, Pb, Cd, and Hg were all below LOD, which is the opposite pattern from HBBF US data. Context matters: these findings reflect the Iranian market supply chain. For HMT&C, Cr data here is for total Cr not Cr-VI; the carcinogenic risk modeling uses a respiratory CSF applied to an oral route, which is a recognized methodological weakness. Do not use these CR values as primary evidence for Cr-VI health endpoints.
Courses: Useful example of probabilistic vs deterministic risk comparison; the Monte Carlo approach is standard in modern risk assessments. Also illustrates that HI >1 driven by multiple metals simultaneously is common in developing-country infant food surveys, even when no single metal exceeds its individual safety threshold.
App: Pb, Cd, and Hg all below LOD in Iranian market formulas 2020–2021. Al and Cr elevated relative to WHO limits. Sample size (80 formula, 27 baby food) is reasonable but single-city and single-year; use as corroborating evidence alongside multi-country surveys, not as primary distribution data for global app estimates.