WAILUKU, Maui — Recent testing of nearly 400 children and pregnant women from Upcountry Maui have showed no sign of elevated lead levels.

The testing was conducted by the state Department of Health as part of a $500,000 Environmental Protection Agency grant to study potential health impacts from lead leaching into the drinking water from pipes in older homes, and examine options for fixing the problem.

Lead exposure can cause damage to the brain and nervous system, behavior and learning problems, headaches, high blood pressure, reproductive problems and other trouble, according to the EPA. Children's brains and nervous systems are more sensitive to lead exposure, and even youngsters who appear healthy can have dangerous levels of lead.

A study 15 years ago by the Centers for Disease Control and Prevention showed that about 6 percent of children in the Upcountry area, which relies on surface water, had high lead levels, compared with about 2 percent for the rest of the island.

Central Maui, Hana and Moloka'i are served by groundwater resources, or "hard water," with a higher alkalinity that provides a protective coating in pipes that prevents corrosion. The Lahaina system also is supplied by surface water, but is supplemented by groundwater that protects the system from corrosion.

In response to a Health Department order to reduce the high lead levels, the county added zinc orthophosphate to the Upcountry water system in 2001 to prevent corrosion. But new health issues arose when more than 140 residents complained of itching, skin rashes and other problems believed to have been related to the additive. The county switched to phosphoric acid in 2003, but complaints continued.

Soda ash, or sodium carbonate, eventually proved to be the solution. The compound lowers the water's acidity, resulting in less corrosion in the pipes.

Maui district health officer Dr. Lorrin Pang said a few residents still report skin problems, with the number rising in the summer. He said the ailments are due to bacteria in residential plumbing. The Health Department is working with the residents to use filtration systems and other measures, he said.

Mayor Alan Arakawa said the test results show that county water systems are safe. "This should be particularly good news for Upcountry families with small children," he said in a statement.

The free lead testing was offered to infants and children up to 6 years old and pregnant women who live in Upcountry. Over a 20-month period that ended June 30, 273 people were tested by the Health Department and an additional 125 were tested through Kaiser Permanente. There were seven initial positives for high lead levels, officials said, but retesting of five of the residents proved negative. Two others could not be found for retesting.

Officials had estimated that hundreds more were eligible for testing. Ha'iku resident Pamela Grossman, one of several Upcountry residents involved in the grant project, said health officials aren't sure why more people didn't participate, and it's possible some may have been tested by their private physicians and the results never reported.

Even with the smaller-than-expected turnout, Pang said, the results have a confidence level of 0 to 0.9 percent, meaning Upcountry residents can be assured the lead problem has been resolved for now. He was not so certain of whether the results could be attributed to the additives, residents flushing their taps or using filters, a natural reduction in lead leaching, or a combination of factors.

Grossman said she's more confident about the water at home.

"We drink the water, and we don't have any filtration systems. I'm very comfortable with it. I feel so much better now than I did 12 years ago," she said.

With the testing done, Grossman said her next task is to educate the public about preventing lead leaching in their home plumbing.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.