Polychlorinated biphenyls are toxic chemicals that were widely used in industry until they were banned in the 1970s.
PCBs can build up in fish.
A new study finds that levels of PCBs are declining in the air in the Great Lakes region. Except for one kind. It’s called PCB-11 and its levels are holding steady.
Ron Hites is a professor at Indiana University. He says researchers believe PCB-11 comes from yellow pigments and the way some yellow pigments are produced.
"A byproduct of that production leads to then PCB-11. So when you find PCB-11 it’s probably related to yellow pigments being used somewhere,” he says.
Hites says this suggests PCB-11 is still leaking into the environment, and he says he’s working to figure out where exactly the chemicals are coming from. One possibility he's investigating: the yellow paint that's used to make the stripes on roadways.