I've just read a news item that the drinking water for the city of Phoenix has been muddied by recent storms and flooding. Residents of the city are being urged to use bottled water or to boil tap water.

This paragraph was included in the story:

Ken Kroski, a spokesman for the Phoenix Water Services Department, said there were no health effects from the "turbidity," or cloudiness, caused by the muddy water. However, it could interfere with water disinfection, provide a medium for bacterial growth, and indicate a presence of disease-causing organisms, he said.

Doesn't the second sentence contradict the Kroski's statement? Or am I thinking too much again?