The Salt : NPR
The fact that a second contaminant in West Virginia's drinking water eluded detection for nearly two weeks — despite intense testing of the water — reveals an important truth about how companies test drinking water: In most cases, they only find the contaminants they're looking for.
Freedom Industries earlier this week revealed it had spilled two chemicals, not just one. The second chemical is PPH, a mixture of polygycol ethers. It was combined with first contaminant — 4-methylcyclohexanemethanol, or MCHM — a chemical that washes coal.
PPH made up about 7 percent of the contents of the tank thatspilled into the Elk River, about 1.5 miles upstream from the treatment plant's intake.
Experts say it's not surprising that the drinking water company did not detect a second contaminant during its search for MCHM.Laboratories can hunt for unexpected chemicals, but generally they don't.
"When water companies do specific tests on contaminants like this they look for a fingerprint, if you will," says Brent Fewell, senior vice president of environment, health and safety of a different water company, United Waters. "Every chemical has a chemical fingerprint. And so when you focus on that fingerprint and you're not focusing on other fingerprints, you very well could miss a contaminant like this."
There are tens of thousands of chemicals in use
