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:
The real question. Apple seeds have naturally occurring cyanide, but you would have to eat something like 30 to 300 apples worth of seeds to maybe have a health issue.
It’s the dose that makes the poison.
Aren’t you better off with plum or peach seeds?
Best not to eat any, but it’s still a matter of dose. Plum/peach seeds may be more a choking hazard than any other.