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 valuesingredients/rice.md— iAs contamination in rice and rice cereal; exposure in infant populationsingredients/rice-cereal.md— if separate page exists, update iAscontamination_profileproducts/infant-rice-cereal.md— iAs exposure contribution; regulatory contextproducts/infant-formula-cow-milk.md— iAs as background exposure source in mixed-feeding scenariosproducts/infant-formula-soy.md— iAs as background exposure sourceproducts/infant-solid-foods.md— category-level iAs profile; rice cereal dominanceregulations/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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