A third round of tests on drinking water at Jefferson Elementary School shows some fixtures, valves and water lines are still leaching concerning levels of lead, according to Medford School District officials.

A third round of tests on drinking water at Jefferson Elementary School shows some fixtures, valves and water lines are still leaching concerning levels of lead, according to Medford School District officials.

Out of 80 water samples, 15 showed levels considered unacceptable by the Environmental Protection Agency.

Schools are held to a higher standard than other entities and are required to take action to reduce the amount of lead in water once it reaches 15 parts per billion, the EPA stipulates.

Fixtures, valves and sections of water lines are being replaced in the areas with unacceptable amounts. Results from yet another round of testing are expected Thursday, said Medford schools Superintendent Phil Long.

"It's really been a process of elimination," Long said. "We are essentially following the EPA protocol until we finally find where all the lead is coming from."

The goal is to lower the levels to less than 10 ppb, Long said.

The 500 or so students at the school and staff members will remain on bottled water until that is accomplished, he said.

Even at small amounts, the toxic metal can have harmful health effects, including behavioral problems and learning disabilities, according to the EPA.

Lead is most dangerous to children 6 years old and younger who may sustain developmental delays as a result of exposure.

In adults, it is more likely to cause high blood pressure and kidney problems. The main source of exposure is breathing in lead paint chips. About 10 to 20 percent of exposure comes from drinking water, according to the EPA.

The lead seems to be coming from the water infrastructure within the school. Tests of the water going into Jefferson showed minimal lead levels of less than 1 ppb, according to the Medford Water Commission.

The 80 samples most recently tested were taken at sinks and drinking fountains throughout the school.

Unlike the previous round of testing when the most concentrated amounts of lead were found in the front of the building, there was no pattern to where the elevated levels were found this time.

"There were sporadic hits around the building," Long said.

It's possible that while flushing out the water system, more lead might have been dislodged, he said.

This round of testing was more comprehensive than the last, in which only 13 samples were tested.

The spike in lead levels was discovered after testing four water samples at the request of a school staff member who expressed health concerns about the water after having some blood work done.

The results came as a surprise, as water tests in fall 2006 showed that lead levels in Jefferson's water were well below the amount considered acceptable by the EPA, Long said.

Reach reporter Paris Achen at 541-776-4459 or pachen@mailtribune.com.