Dimethylated Thioarsenates: A Potentially Dangerous Blind Spot in Current Worldwide Regulatory Limits for Arsenic in Rice
Britta Planer‐Friedrich, Carolin F. Kerl, Andrea E. Colina Blanco, Stephan Clemens
Abstract
Arsenic (As) occurrence in rice is a serious human health threat. Worldwide, regulations typically limit only carcinogenic inorganic As, but not possibly carcinogenic dimethylated oxyarsenate (DMA). However, there is emerging evidence that "DMA", determined by routine acid-based extraction and analysis, hides a substantial share of dimethylated thioarsenates that have similar or higher cytotoxicities than arsenite. Risk assessments characterizing the in vivo toxicity of rice-derived dimethylated thioarsenates are urgently needed. In the meantime, either more sophisticated methods based on enzymatic extraction and separation of dimethylated oxy- and thioarsenates have to become mandatory or total As should be regulated.