Water in the Chapel Hill area is very pure. When pure water flows through new brass plumbing fixtures, though, the reaction can cause lead to leach from the brass initially.

That situation, commonly seen in new construction around the country, seems to be the reason four campus buildings recently showed elevated lead levels in some water samples.

In March, after building occupants complained of bad taste in the water, University officials tested the water in Caudill Labs and Chapman Hall. When the test results showed elevated levels of lead in the water, officials also tested the Campus Y, Information Technology Services (ITS) Manning and the FedEx Global Education Center.

Water in the FedEx Global Education Center showed no signs of elevated lead levels. When testing in the other buildings showed elevated lead levels in some water samples, University officials restricted water use and supplied bottled water for drinking.

 “The purer the water, the more likely it is to leach lead from brass. You are both blessed and cursed by high-quality water,” said Marc Edwards, Charles Lunsford professor of civil and environmental engineering at Virginia Tech. As a consultant, Edwards is guiding the University’s investigation into the situation.

The problem is resolved over time, Edwards said. As water flows through the brass fixtures, a protective film is formed that shields against leaching. Flushing the water lines hastens the formation of the protective film, he said. Edwards was on campus May 15 to discuss updated test results and answer questions from people who work and study in Caudill Labs, Chapman Hall and ITS Manning.

Following Edwards’ direction, within the last few weeks the Department of Environment, Health and Safety (EHS) has systematically flushed the water in the four affected buildings and retested sample fixtures.

When none of the sample tests within a building shows elevated lead, officials will test each fixture that can reasonably be expected to provide water for human consumption in the building. If none of the fixtures shows elevated lead levels, the building will be declared safe for unrestricted water use. The Campus Y was cleared for unrestricted use in mid-May, and the other three buildings are undergoing final testing the week of May 21.

This testing involves a three-to-five-minute period of flushing the lines at night, followed by a 12-hour period of not using the water at all to simulate regular use. Officials then will take two water samples from each fixture. One sink in each bathroom will be available so that employees can wash their hands, but all water fountains and sinks in break rooms will be taped off during the testing, said Ray Hackney, EHS interim director.

“If any individual fixtures show elevated lead levels, we either will replace them or further remedy them, following the procedure Dr. Edwards outlined, before we clear those fixtures for use by the occupants in the buildings,” Hackney said.

All buildings currently under construction in which plumbing fixtures have already been installed will be flushed and tested according to a protocol provided by Edwards before the buildings are opened for occupancy. This protocol was used for the first time earlier this month to ensure that the Daily Grind coffee shop in the renovated Daniels Student Stores Building had no elevated levels of lead, Hackney said.

All future construction and new construction where plumbing fixtures have not yet been installed will be required to have fixtures with a maximum of 0.2 percent lead. The current standard for a fixture labeled “lead-free” in most states, including North Carolina, allows up to 8 percent lead. Fixtures with a maximum 0.2 percent lead should ensure that the problem does not resurface, officials said.

Public health officials with whom the University has consulted believe that the lead levels found to date do not raise a concern for adults who have been drinking the water, particularly given the short time of exposure.

Robert Goyer, retired deputy director of the National Institute for Environmental Health Sciences and former faculty member in the School of Medicine, who is an expert on the health effects of lead, also spoke at the May 15 meeting. He agreed that the situation did not pose a health risk for adults. The University has offered free testing for pregnant or nursing women who drank water in any of the affected buildings. Eleven people have been tested.

“All the lead levels were within what we would expect to see in the general population,” Goyer said.

The Orange Water and Sewer Authority (OWASA), which provides water to homes, businesses and organizations in the Chapel Hill-Carrboro area, has begun examining drinking water outside campus. In the coming weeks, OWASA will test for lead in the water in buildings that are less than two years old.

OWASA officials also have engaged Edwards to evaluate possible changes in the drinking water treatment process to explore ways to reduce the potential for the release of lead from plumbing systems into drinking water.

The latest test results and the PowerPoint presentations by Edwards and Goyer are available on the EHS web site, www.ehs.unc.edu.

To read OWASA's report on its tests for lead in the UNC buildings, click here.