Key Numbers

Inorganic Arsenic Concentrations in Rice Cereal (FDA survey)

• Range: 0.023–0.283 mg/kg iAs
• Mean: ~0.100 mg/kg iAs
• Rice cereal accounted for approximately 55% of total iAs exposure in infants 4–24 months

Exposure Assessment (Monte Carlo, n=1,000,000 iterations)

Infants 4–6 months:

• Mean daily intake: 0.46 μg/kg/day iAs
• 95th percentile: 1.32 μg/kg/day iAs

Infants 7–12 months:

• Mean daily intake: 0.32 μg/kg/day iAs
• 95th percentile: 0.85 μg/kg/day iAs

Toddlers 13–24 months:

• Mean daily intake: 0.28 μg/kg/day iAs
• 95th percentile: 0.75 μg/kg/day iAs

Hazard Quotient for Chronic Non-Carcinogenic Risk

• ATSDR chronic MRL: 3.0 × 10⁻⁴ mg/kg/day
• HQ exceeded 1.0 at 50th percentile for 4–6 month-olds
• HQ exceeded 1.0 at 75th percentile for 7–12 month-olds
• HQ remained below 1.0 for 13–24 month-olds at all percentiles

Incremental Lifetime Cancer Risk (ILCR)

• EPA cancer slope factor: 1.5 (mg/kg/day)⁻¹
• 4–6 month-olds: ILCR 10⁻⁶ to 10⁻⁵
• 7–12 month-olds: ILCR 10⁻⁶ to 10⁻⁵
• 13–24 month-olds: ILCR below 10⁻⁶ at mean, 10⁻⁶ to 10⁻⁵ at 95th percentile

Regulatory Reference Values and Proposed MCL

• ATSDR acute MRL: 5.0 × 10⁻³ mg/kg/day
• ATSDR chronic MRL: 3.0 × 10⁻⁴ mg/kg/day
• EPA oral RfD: 3.0 × 10⁻⁴ mg/kg/day
• FAO/WHO proposed maximum level for polished rice: 0.2 mg/kg
• Derived MCL (chronic exposure at ATSDR MRL, 4–6 month infants): 0.0 mg/kg (practical limit)
• Derived MCL (acute exposure at ATSDR MRL): 0.4 mg/kg

Methods

Exposure Assessment Framework

• Hazard identification: iAs classified as Group 1 carcinogen; dose-response derived from epidemiological and animal studies
• Exposure pathways: rice cereal (primary), other solid foods, drinking water, infant formula
• Body weight and dietary intake: age-stratified (4–6, 7–12, 13–24 months); assumed exclusive rice-cereal consumption for 4–6 month cohort in sensitivity analysis
• Probabilistic modeling: Monte Carlo simulation (1 million iterations) to characterize exposure distribution and percentiles

Risk Characterization

• Non-carcinogenic risk: Hazard Quotient (HQ) = exposure ÷ ATSDR MRL; HQ > 1.0 indicates potential for adverse effects
• Carcinogenic risk: ILCR calculated as mean daily intake × cancer slope factor; risk interpreted relative to EPA benchmark of 10⁻⁶

Data Sources

• FDA 2012–2013 retail rice cereal survey: 116 samples analyzed for total and inorganic arsenic
• NHANES dietary intake data: age-specific consumption patterns and body weight distributions
• Drinking water: USDA data for iAs in municipal and private well supplies

Wiki Pages Updated on Ingest

• metals/arsenic.md — inorganic arsenic toxicology, dose-response, regulatory values
• ingredients/rice.md — iAs contamination in rice and rice cereal; exposure in infant populations
• ingredients/rice-cereal.md — if separate page exists, update iAs contamination_profile
• products/infant-rice-cereal.md — iAs exposure contribution; regulatory context
• products/infant-formula-cow-milk.md — iAs as background exposure source in mixed-feeding scenarios
• products/infant-formula-soy.md — iAs as background exposure source
• products/infant-solid-foods.md — category-level iAs profile; rice cereal dominance
• regulations/us-fda-closer-to-zero.md — iAs baseline for infant foods; gap between current survey mean and precautionary levels

Page history

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