by Sara Jerome, originally posted on February 06, 2017

Copper contamination at a middle school in Minnesota made at least ten students sick last month after they drank from a school water fountain.

“Water tests at Horizon Middle School in Moorhead came back positive for copper contamination,” KRVV reported.

“Moorhead Public Service and Fargo’s Water Treatment Plant are getting lots of calls after reports of water contamination that sickened several students at Horizon Middle school,” WDAY News reiterated.

“The superintendent tells us she thinks it was caused by water not running through the pipes over winter break. After flushing the system, test results came back normal,” Valley News Live reported.

The contamination resulted in a two-hour delay, the report said. The school decided to block off the fountains when students returned.

Mark Peterson, a top official at the Fargo Water Plant, told WDAY News that in this situation, the copper is in the plumbing, rather than the water itself. Water sometimes turns a blue tint due to copper contamination.

“If water sits in contact with pipe for extended period of time, it can tend to dissolve some of that copper,” said Kristofer Knutson, Water Division Manager, Moorhead, per the report.

Peterson and Knutson worked to reassure the public that their water is safe.

“The issue that Horizon Middle School is experiencing is what we call a premise plumbing issue, so something that occurred likely in the facility,” Knutson said, per the report.

Moorhead officials ran tests on the water near the school and found the water was safe, according to the report.

The World Health Organization notes that “at lower doses, copper ions can cause symptoms typical of food poisoning (headache, nausea, vomiting, diarrhea).”

The U.S. EPA explains the federal limit for copper in drinking water: “If… copper concentrations exceed an action level of 1.3 ppm in more than 10% of customer taps sampled, the system must undertake a number of additional actions to control corrosion.”