BENTON — New test results from the Kennebec Water District show that abnormally high lead levels in the water at Benton Elementary School might have been caused by brass in parts of the plumbing system.

After initially finding levels of lead in the water at the school higher than the federal action level, further tests resulted in consistently low levels, leaving officials both pleased and perplexed.

The school is continuing to hand out bottled water for drinking and cooking as a precaution, and it will continue to do so until all the fixtures that need to be changed have been changed, school Superintendent Dean Baker said. Baker also said the school has not had any reports of ill effects, although some students and teachers did have blood tests that came back normal.

While the tests are not definitive, results point toward plumbing in the school’s mechanical room near the water meter.

Water goes through the meter and then a set of pipes, some of which are brass, before it goes to into the internal plumbing system, said Jeff LaCasse, general manager of the Kennebec Water District. Older brass tends to contain some lead, LaCasse said, and could be a potential source of lead leaching.

Action must be taken when more than 10 percent of samples show a water supply’s lead level is above 15 parts per billion for residential areas and 20 ppb for schools, according to the Environmental Protection Agency.

After running through the brass pipes, the first fixture the water goes by is the cafeteria sink, which had the highest level of lead, at 670 parts per billion. In both the second and third tests, the lead levels were well below the action level at the first draw, after running the water for 15 seconds and after running it for one minute.

A first draw sample, which is the first 8 ounces that comes out of the faucet, taken at the water meter in the second round of testing had a level of 180 ppb, which led to the investigation of the piping.

The water district has replaced the water meter with a lead-free version, Principal Brian Wedge said. The school plans to replace to the brass fittings and pipes as well.

LaCasse said that instituting a flushing regimen, which means the school would run the water fixtures each morning to drain out what sat in the pipes overnight, also could help overcome the potential problem of lead leaching.

The water district still hasn’t been able to pinpoint how the excessive first readings happened. It also hasn’t seen a replication of the higher levels in any of the tests that followed.

In its report, however, the district says that “it does not appear that the fountains and faucets tested were the source of the high initial lead levels.”

A.E. Hodsdon Engineers also took water samples and sent them to Northeast Laboratory in Winslow for a comparison. The results were all below the action level, Baker said.

The initial tests were taken Oct. 14 as a “goodwill gesture” toward the school in light of the national spotlight on lead in water. Lead is most dangerous to children, who can suffer mental and physical developmental delays if exposed to lead for long periods of time.

The water district was surprised to find high lead levels in all three sites it tested — 57 parts per billion, 78 ppb and 670 ppb. Once the school was notified of the high levels, it immediately turned off drinking fountains and provided bottled water for drinking and cooking.

Baker said they are continuing with the same precautions until each fixture is changed and another round of testing is done.

“Anything that was brought into question is going to be replaced,” he said.

Madeline St. Amour — 861-9239

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Twitter: @madelinestamour