The mechanistic pathways of arsenic transport in rice cultivars: Soil to mouth

Rice cultivars are major conduit of arsenic (As) poisoning to human. We quantified transferability of fifteen rice cultivars representing three groups i.e., high yielding variety (HYV), local aromatic rice (LAR) and hybrid for As from soil to cooked rice and its ingestion led health risk, elucidating the processes of its unloading at five check points. Conducting a field experiment with those cultivars, we sampled roots and shoots at tillering, booting and maturity (with grains), separated the grains into husk, bran and polished rice, cooked it through different methods and analyzed for As. Of the tested groups, As restriction from root to grain followed the order: LARs (94%) > HYVs (88.3%) > hybrids (87.2%). The low As sequestration by LARs was attributed to their higher root biomass (10.20 g hill−1) and Fe-plaque formation (2421 mg kg−1), and lower As transfer coefficients (0.17), and higher As retention in husk and bran (84%). On average, based on calculated four major risk indices, LARs showed 4.7–6.8 folds less As toxicity than HYVs and hybrids. These insights are helpful in advocating some remedies for As toxicity of the tested rice cultivars. [Display omitted] •Five check-points to curb As flow from soil to mouth via rice plants quantified.•Order of As transferability from soil to cooked rice: Hybrids >HYVs>LARs.•Low transferability of LARs owed to root biomass, Fe plaque and processing losses.•As drop in cooked rice depends on raw rice As, cooking water and method of cooking.•ADI, HQ, ILCR and SAMOE of LARs found to be safer over HYVs and hybrids.