Quantitative Evaluation of Arsenic Exposure from Baby Rice Cereal

Arsenic contamination in baby rice cereal, which is one of the most common first solid foods, is a rising concern because there are no set standards or quantitative guidelines available for food products in the U.S.  The objective of this study was to evaluate whether detected arsenic levels in baby rice cereal (e.g. 1.2x10^-4±4.7x10^-5 mg/g) were safe for consumption by young children.  The average daily dose (ADD) and chronic daily intakes (CDI) were estimated  from the reported inorganic arsenic concentrations in rice cereal  and the recommended amounts of rice cereal consumed by infants and toddlers based on their body weights between ages  four to 24 months, in the literature.  Hazard quotients (HQs) for acute and chronic exposures were calculated based on ADD with the ATSDR’s minimal risk level (MRL)_acute (5.0x10^-3 mg/kg/day) and CDI with MRL_chronic (3.0x10^-4 mg/kg/day).  A maximum contaminant level (MCL), the highest level of inorganic arsenic allowed, in rice cereal was computed considering the MRL_chronic from other sources (e.g. drinking water, formula, fruits, vegetables, and meats).  A Monte Carlo simulation was performed and showed that ADD (3.7x10^-4 at 50^th and 1.3x10^-3 mg/kg/day at 90^th percentile) and CDI calculations (8.8x10^-6 at 50^th and 3.0x10^-5 mg/kg/day at 90^th percentile).  The HQ_{acute and chronic} from rice cereal were 0.25 and 0.10 at 90^th percentile, respectively.  Even though the trace levels of arsenic detected in rice cereal could be allowable, it is possibly the largest single source (53%) of inorganic arsenic for young children followed by drinking water (18%), which is regulated.  The study suggests monitoring rice cereal for inorganic arsenic based on a MCL of 2.2x10^-3 mg/g (or total arsenic of 3.6x10^-3 mg/g assuming that 60.5% of total arsenic in rice cereal is inorganic).  Further investigation is required for potential policy interventions in order to protect public health.