New EPA rules could allow for more polluted waters, and tribes and state officials are worried

Some researchers say the extent of possible changes to health risks based on the water quality standard adjustments are difficult to pin down.  

"Anytime a regulation is changed, there's actually a calculation that's supposed to be done. There are often assumptions made in these calculations,” says Dr. Wayne Landis, director of the Institute of Environmental Toxicology at Western Washington University. “If someone raises the amount of a chemical like a PCB in an organism that's allowed for you to eat, that will increase the probability of getting the disease. [But] the amount that it will increase that probability is really hard to determine.”

Dr. Robin Matthews, outgoing director for the Institute of Watershed Studies at Western Washington University and an expert in aquatic ecology, says changing water quality regulations without following appropriate processes is worrying. 

“Water quality standards should only be changed when there's a strong scientific basis for it. Most of the water quality standards, it took years to develop them. And so changing them without an extensive review period makes me quite nervous,” she says. “If anything, we've seen pretty consistently that we tend to underestimate risks.”