To add to what @ShiftyThomas said
Now, some ways of cooking rice reduce arsenic levels more than others. We carried out some tests with Prof Meharg and found the best technique is to soak the rice overnight before cooking it in a 5:1 water-to-rice ratio.
That cuts arsenic levels by 80%, compared to the common approach of using two parts water to one part rice and letting all the water soak in. Using lots of water - the 5:1 ratio - without pre-soaking also reduced arsenic levels, but not by as much as the pre-soaking levels.
So, while I would now think twice about feeding young children too much rice or rice products, I'm not going to stop eating rice myself. I will, however, be cooking it in more water and, when I remember, leave it to soak overnight.
...This is why rice contains about 10-20 times more arsenic than other cereal crops. But are these levels high enough to do us any real harm?
The only thing I can really equate it to is smoking," says Prof Andy Meharg of Queen's University Belfast, who has been studying arsenic for decades. "If you take one or two cigarettes per day, your risks are going to be a lot less than if you're smoking 30 or 40 cigarettes a day. It's dose-dependent - the more you eat, the higher your risk is.
See the article for more information:
Should I worry about arsenic in my rice?
By Dr Michael Mosley, BBC, 10 February 2017