The Virginia Department of Health is continuing to investigate the cause of an August water contamination in Orange County.
“Our goal is to figure this out,” said Dwayne Roadcap, director of the VDH Office of Drinking Water.
VDH, the local health district and water treatment plant operator Rapidan Service Authority issued a “Do Not Use” advisory on Aug. 21. It was eventually downgraded to a “Do Not Drink” advisory before being fully lifted on Aug. 27.
Eastern Orange County residents served by the Wilderness Water Treatment Plant reported an oil-like smell coming from the public water supply. VDH and RSA stated that the smell had dissipated from the treatment plant by the time the advisory was lifted.
Last week, VDH reported that it was taking a closer look at a few contaminants identified in laboratory testing of water samples from the treatment plant.
A colorless solvent called BCEE was detected in an Aug. 21 sample, though it hasn’t appeared in subsequent samples. VDH’s incident report website states the chemical is not known to have adverse health impacts due to short-term exposures.
Another chemical, TPIB, also appeared in laboratory tests — although a third-party lab told VDH officials it may have been a false positive. More tests on samples from the contamination event are still being evaluated.
The more likely cause of the issue to ODW is isovanillin, a compound used in pharmaceutical production and food products. It was found both in samples from a restaurant that reported odor in its water and in a basin at Rapidan's treatment plant that was cordoned off for testing. Water from that basin is not being used in the water supply.
Roadcap said isovanillin is also used in WD-40, which matches anecdotal descriptions of the odor.
“We feel like we’ve identified what the cause of the odor is and now we’re trying to figure out what the source of that odor was,” Roadcap said.
Officials are attempting to trace those chemicals back to other compounds that could have been partially broken down by the treatment plant’s chlorine-based water purification system.
“It’s possible we’re dealing with a different chemical,” Roadcap said.
Finding answers there could narrow down possible sources of contamination upstream of the treatment plant.
RSA and VDH are also investigating pump failures at the treatment plant around the time of contamination. One pump failed less than a week before reports of an odor started coming in, while three other pumps failed in the days after the event began. RSA reported the post-event failures were due to electrical issues.
A representative for RSA did not respond to a request for comment by the time of publication.
The utility recommends residents flush their systems if they still detect an odor and continue reporting the odor as long as it persists.
