arsenic is a fairly common compound, both in natural form (mines) and as a chemical. it has multiple uses, including medical. yes, some forms of arsenic were used to treat syphilis, others are approved for cancer treatment. it can be found in water, soil, air and food. many water supplies are contaminated - naturally - by arsenic and contain level higher than it is suitable for human consumption but not high enough to immediately poison anyone.
it is normal to have trace arsenic in food, nothing to write home about. i hate how media create hype around those events and push people into living in fear. it's one thing to have awareness of what really is in your food and another thing to be paranoid about it.
I always like more beans and less rice anyway. Like my rice nice and wet.