>>1253Arsenic content in rice depends on 2 factors:
1. Soil. Rice grown in soils with higher arsenic content accumulates more rice in the grains. Depending on your country, there may be maps available showing arsenic concentrations in soil.
2. Degree of processing. Arsenic is more concentrated in the bran (brown exterior layer) than the endosperm (white center). So white rice (which is really just brown rice with the bran removed) tends to be lower in arsenic. But white rice is also lower in vitamins for the same reason (vitamins are also more concentrated in the bran), so it's a tradeoff.
Sickness from reheated rice is usually from Bacillus sp. toxins. Bacillus sp. forms spores that are highly resistant to heat and may survive boiling/desiccation. Uncooked rice often has some inactive spores in it that get activated by the cooking. It's not usually a problem in freshly cooked rice or rice that is refrigerated soon after cooking, but if you leave cooked rice at lukewarm or room temperature for hours, the spores can grow into bacteria which then start multiplying on the cooked rice and produce toxins.
