Why you should know:
Arsenic is a carcinogen and has various other negative health effects; enough to warrant exposure limits in various jurisdictions. A five minute boil-and-discard step before cooking is a simple way to reduce your exposure, especially if you eat a lot of rice.
Details are in the study, linked in the title of this post. Here’s a diagram from the abstract:
Let’s do the math. Rice contains about 0.4 mg/kg As by weight. The “bad” rice in Louisiana or whatever contains about 75% more - about 0.7 mg/kg. Let’s round up to 1 mg/kg to make the math easy. Chronic exposure limits for a 50 kg adult are about 5 mg/day (on the low end).
So you’d have to choke down a full 10 lb bag of rice every day (about 110 cups of cooked rice) to start to tip the scales. Other sources of arsenic, like groundwater, are likely far more significant.
Comment stolen from reddit
Soooo it’s safe to eat without throwing the eater out?
Well, if you were previously throwing anyone who ate the rice in the garbage, then yes, not doing that would be safe.
sorry, I ^couldn’t ^ resist. yes, it’s safe to eat rice without throwing out the first batch of water. see rest of this thread for nuance.
Challenge accepted.