Rice. It’s just one of the basics, right? Whether eaten on its own, or in products like pastas or cereal, this inexpensive and healthy food is a staple for Asian and Latino communities, as well as the growing number of people looking to avoid gluten.

Here’s the bad news (cue Debbie Downer sound effect): The food most of us think we have more or less locked down is shockingly high in arsenic. And arsenic, especially the inorganic form often found in rice, is a known carcinogen linked to several types of cancer, and believed to interfere with fetal development.

According to new research by the Consumers Union, which took over 200 samples of both organic and conventionally grown rice and rice products, nearly all the samples contained some level of arsenic, and a great deal of them contained enough to cause alarm. While there is no federal standard for arsenic in food, according to the Consumers Union, the advocacy arm of Consumer Reports, one serving of rice may have as much inorganic arsenic as an entire day’s worth of water. (They’ve also created a useful chart of various rice products, rice brands, and their arsenic levels.)

Rice often readily absorbs arsenic from soil where chemical-heavy cotton once grew. (Photo by Shutterstock.)

How does rice compare to other grains like wheat and oats? It turns out it’s much higher because of two main factors: How and where rice is grown. The November issue of Consumer Reports,released today, breaks down both phenomena. First, the how:

Rice absorbs arsenic from soil or water much more effectively than most plants. That’s in part because it is one of the only major crops grown in water-flooded conditions, which allow arsenic to be more easily taken up by its roots and stored in the grains.

Then, the where:

In the U.S. as of 2010, about 15 percent of rice acreage was in California, 49 percent in Arkansas, and the remainder in Louisiana, Mississippi, Missouri, and Texas. That south-central region of the country has a long history of producing cotton, a crop that was heavily treated with arsenical pesticides for decades in part to combat the boll weevil beetle.