The Minnesota Department of Health is changing the way it tests the state's drinking water for certain contaminants after finding some of its procedures were "inconsistent" and "inadequate."
The concern is that tests done over the past two decades may have underreported the level of some chemicals in people's drinking water, the health department said in a news release Thursday.
Although the risk to people's health is extremely low, Health Commissioner Dr. Ed Ehlinger says they "want to ensure we have the highest level of reliability in our data on drinking water quality."
Ehlinger added, “This inconsistency is unacceptable and should not have happened. We’re moving swiftly to correct it.”
So what happened?
The health department routinely samples public drinking water from around the state. The agency uses these samples to test for chemicals and other compounds that could affect the quality of the water.
Some organic chemicals and inorganic compounds, including fertilizers and cyanide, show up better when water is cooler – federal guidelines for monitoring these compounds require samples to be kept at around 40 degrees when being transported from the collection site to the lab.
But in some cases, the health department says samples were transported at room temperature. That could degrade the sample, meaning test results could be lower than the true value. (Although, the health department says it's unlikely the data is off by a lot.)
This situation didn't involve water samples taken to look for viruses or other infectious agents, fluoride, radionuclides, arsenic, lead, mercury or other heavy metals.
“Even though that evidence would suggest the risk to communities is low, recent events like the case in Flint, Michigan, show the special expectations that exist around drinking water safety,” MDH Environmental Health Division Director Tom Hogan said in the release.
Hogan says these inconsistent practices have been in place since the early 1990s, noting they are working to resample systems that are at the "greatest potential to be affected by the temperature inconsistencies."
The health department says it expects to be done re-sampling the water that could be most affected by this situation by this summer.