(CBS News) -- Since a Consumer Reports study released in recent weeks found 10 percent of store-bought apple and grape juice contained unhealthy levels of the chemical, other foods are now under scrutiny.
Rice, a new study finds, may also contain dangerous levels of arsenic, as well.
Rice is of particular interest because of the way it is grown," medical contributor Dr. Holly Phillips explained on "The Early Show."
"Arsenic is in chemical that's in our soil and rocks naturally," she said. "But for many years in the United States, it was added to our soil in the form of pesticides. That's a more dangerous form of the chemical called inorganic arsenic. It turns the out that the way that rice is grown, in the soil with a lot of water makes it particularly able to soak up arsenic. And so it gets concentrated in the rice and subsequently with eat it."
The Dartmouth study was based on findings of 200 pregnant women; some ate a half-cup of rice a day while others had none. Researchers tested their urine and found women who had a half-cup of rice for just two days had 53 percent more arsenic in their urine than women who didn't, Phillips said.
"It really shows rice can be a source of this chemical," Phillips said. "But we just don't know exactly how much is too much. But we do know it affects fetuses. It can affect pregnant women; it can affect the unborn baby. So, as much as we can avoid it, is a good thing. It's all about how much you're exposed to."
Phillips said you would likely have to have gallons and gallons of rice to really put yourself in danger, but she added, "that doesn't mean we shouldn't follow it closely."
"(The Environmental Protection Agency) regulates how much arsenic is in our drinking water. (The regulation is) 10 parts per billion," Phillips said. "It is not uncommon for rice to have 100 parts per billion or even up to 2,000 parts per billion. Now, in extremely high doses, arsenic can cause cancers, particularly liver cancer, kidney cancer and lung cancer, as well as bladder cancer. It's linked with heart disease, diabetes and some neurological problems in children. But the real question here is how much arsenic are we dealing with? And we don't know that yet. But what this study shows is that we might want to take a closer look at our dietary sources."
There's not a way to avoid arsenic completely, Phillips said, but you can "make a difference," she said, by selecting organic products that are particularly high in arsenic, such as chicken, apple juice -- and rice.
"Even rice cereals and rice milk we need to be careful of," Phillips said. "You should get your water tested, particularly if you have well water. City water is tested automatically. Or, if you have concerns, you can get yourself tested. It's a very easy blood test at the doctor's office."