Overview
Weber and colleagues measured total arsenic and arsenic species in 53 rice brans from 10 countries, a field trial comparing irrigation and an arsenical herbicide soil treatment, organic and conventional bran, and probiotic-fermented bran. Inorganic arsenic averaged 0.463 mg/kg and tracked total arsenic closely. Alternate wetting and drying gave lower arsenic than flooding.
Key numbers
- All 53 brans: total arsenic 0.609 ± 0.393 mg/kg (0.017 to 1.86); inorganic arsenic 0.463 ± 0.243 mg/kg (0.012 to 1.17) (Section 3.1, p. 4).
- Native-soil field trial: inorganic arsenic 0.502 mg/kg with alternate wetting and drying vs 0.803 mg/kg flooded (Section 3.3, p. 4).
- US bran (n = 20): total arsenic 0.771 ± 0.310 mg/kg, the highest country mean; Guatemala 0.023 mg/kg the lowest (Section 3.2).
Methods (brief)
Arsenic species were separated by ion chromatography and read by ICP-MS; total arsenic by triple-quadrupole ICP-MS after digestion. Rice flour and peach leaf reference materials were analyzed. Per-sample results are in a supplementary table that was not available, so only text summaries are recorded.
Evidence Fitness
Peer reviewed with good analytical QA, but the sample is a convenience set, several groups have n = 1 or 2, and the field-trial and MSMA brans are experimental. The text and figure captions conflict on the organic vs conventional numbers and on the Thai value. The paper measures rice bran, not rice bran oil: it is a proxy for rice-bran-oil, which is not linked; arsenic in bran does not show how much reaches the extracted oil.