The water contamination advisory has been issued for the entire Tyrnävä municipality in northern Ostrobothnia, with the exception of the former Temmes district. The area is home to nearly 2,000 households and 6,000 residents. An official warning was issued Thursday afternoon.
Water samples taken from the Kukkolanvaara intake facility Monday were found to contain Escherichia coli or E. coli bacteria, however water in the distribution system was found to be clean.
By Wednesday however, coliform bacteria and E. coli bacteria were detected in new samples taken from the intake system and the distribution network.
The Kukkolanvaara intake facility was taken offline Wednesday.
“We are now flushing the distribution system and we have taken control samples today. They are now being examined in the laboratory and we’ll have the results Friday,” said head of Tyrnävä Water Supply Company Kalevi Sarsila.
Cause of the contamination unclear
The Oulu Environment Department and the water company are speculating that the bacteria come from surface water which has entered the intake system.
The presence of E. coli bacteria in drinking water is sign of contamination by human waste; this in turn could indicate contamination by disease-causing bacteria and viruses.
“We don’t know why. We can guess that surface water could have entered the intake and that is also speculation. It’s the most common explanation. The Kukkolanvaara area was checked yesterday and nothing out of the ordinary was detected,” Sarsila explained.
He added that there had so far been no reports of residents falling ill.
“I talked with the health centre doctor this afternoon and there had not been any cases of illness,” Sarsila noted.
