Two suburban Detroit schools have been temporarily closed after a science experiment found high levels of mercury in a water sample.
The Rochester Community Schools district says students were dismissed early Monday and classes at Van Hoosen Middle School and Rochester Adams High School were canceled Tuesday for water tests.
Officials say school drinking water sources have been shut off.
The district says it learned about the water issue from a laboratory manager after samples were taken by a teacher at the middle school.
Three water samples were tested and one from a science room faucet was above a recommended federal threshold.
The middle school and high school use the same water, so they were closed as a precaution so testing by certified personnel could take place.