The Methylmercury Lab
Rice baby cereals are a dietary source of inorganic arsenic; however, less is known concerning methylmercury concentrations in rice baby cereals and rice teething biscuits.
Between September 2016 and June 2017, we purchased 36 boxes of rice baby cereals, eight boxes of rice-containing teething biscuits marketed to infants, and four boxes of baby cereals manufactured with wheat or oats. All products were purchased in the U.S., including South Carolina (n=28), California (n=9), Ohio (n=6), New York (n=3), and Florida (n=2).
Methylmercury concentrations were measured in 36 rice baby cereals, eight rice teething biscuits, and four baby cereals manufactured with oats/wheat (n=48 total). Arsenic species, including inorganic arsenic, were determined in rice baby cereals and rice teething biscuits (n = 44/48), while total arsenic was determined in all products (n = 48). Rice baby cereals and rice teething biscuits were on average 61 and 92 times higher in methylmercury, respectively, and 9.4 and 4.7 times higher in total arsenic, respectively, compared to wheat/oat baby cereals. Inorganic arsenic concentrations in two brands of rice baby cereal (n = 12/36 boxes of rice cereal) exceeded 100 ng/g, the proposed action level from the U.S. Food and Drug Administration.
We concluded rice-containing baby cereals and teething biscuits were a dietary source of both methylmercury and inorganic arsenic.
Rothenberg, S.E., Jackson, B.P., McCalla, G.C., Donohue, A., Emmons, A.M., (2017). Co-exposure to methylmercury and inorganic arsenic in baby rice cereals and rice-containing teething biscuits. Environmental Research. 159, 639-647. PMID: 28938205 PMCID: PMC5661960. https://doi.org/10.1016/j.envres.2017.08.046