When soil in a rice paddy is waterlogged, oxygen gets depleted, causing the soil bacteria to rely further on arsenic to generate energy. The end result is more arsenic building up in the rice paddy, and more roots to take it up to the developing grain. https://grist.org/food-and-agriculture/the-king-of-poisons-arsenic-is-building-up-in-rice/?utm_medium=email&utm_source=newsletter&utm_campaign=daily