Well owners in the vast majority of this region may want to have their water sources tested for radiological contaminants.
In a report released earlier this month, Insightus, a Durham-area data science nonprofit, shed light on significant findings of uranium in 40 out of more than 400 Wake County well water samples submitted to the state lab for uranium testing from 2010-14.
Consuming water that contains high levels of the chemical element for extended periods of time is associated with an increased risk of kidney damage and cancer, according to the Centers for Disease Control and Prevention.
It was Wake County health officials who initiated the 400-plus tests Insightus examined.
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Wake spokeswoman Jennifer Heiss said a sample submitted by an east Raleigh resident in 2010 caught the attention of county health officials.
Private well water quality is not regulated at the federal, state or county level, but the federal limit for uranium in community water systems, of 30 micrograms per liter of water, is generally applied as a safety standard for private wells. The east Raleigh sample turned up a reading of 412 micrograms per liter, more than 13 times over the federal standard.
“We resampled it in April, 2010 to confirm the elevated levels of uranium, and that led to us testing the wells for uranium in the eastern Wake County area,” Heiss said.
The Rolesville Granite
The county had one, big, obvious reason to concentrate its tests on the eastern Wake region: a large geologic formation known as the Rolesville Granite that covers about a third of the county.
The granite bedrock is also found in portions of Franklin, Vance, Warren, Halifax, Nash, Johnston, Wilson and Edgecombe counties.
“There are pockets of different minerals with a large formation like that, that are left there as the rock forms,” said Michael Orbon, Wake County water quality director. “If you drill a well into minerals in a specific location that contains uranium compounds, they can dissolve into the water, or the water can be affected by merely being in contact with an open rock face.”
Heiss said the county was behind on entering data that comes in paper form from the state lab. Wake moved to utilizing private labs as a first option in 2014, because of “the price and just the amount of time it would take to get the results back,” from the state lab.
Out of 387 samples collected by Wake County from 2010 through 2014, Heiss said uranium was detected in 190 and 37 were found to be at levels exceeding the federal drinking water standard.
Insightus’s report shows the eastern Wake region to be a hot bed for those samples testing above the federal limit. The highest result of all the county tests, yielding 1,970 micrograms of uranium per liter of water, or about 65 times over the federal limit, was reported in the Woods Plantation subdivision north of Zebulon.
“I’m definitely going to check for uranium in my water,” said Bruce Allen, whose home is located nearby the residence that had the highest test result in the neighborhood that has developed over the past decade.
Matching Insightus’ claim, Allen said he was surprised results showing toxic levels of the substance in the area were not publicized by the county.
“It’s a serious problem,” Allen said, noting that his well and the most-affected well draw water from the same aquifer.
The Insightus report points a finger at health officials from Wake County for failing “to share critical public health information across county lines,” and at the state, saying they “failed to promote a coordinated statewide response to this public health threat which its own laboratory had documented.”
But Orbon, the county water quality director, said there was reason for not sounding a region-wide alarm.
He said someone can dig a well into a pocket of uranium and taint that well, but that a well a matter of feet away could have no uranium at all.
“When you’re in rock or fractured rock, it’s not homogenous – it differs from point to point,” Orbon said. “I’ve been in places where you could move the well 3-to-15 feet and it would be the difference in having water in the well or no water in the well.
“If an aquifer is contaminated, you’ll get hits after hits after hits of wells next to each other that are contaminated. That’s not what we’re seeing. We’re seeing pockets, and there’s really no way to specify where they are.”
Orbon said the fact that the uranium is a naturally occurring contaminant makes it hard to pinpoint with a high level of certainty.
The county notified the users of wells that tested high for uranium and continues to do so, according to Wake hydrogeologist Evan Kane.
“Anytime we test a well, whether related to permitting a well or at the request of the resident, we don’t just test the well and give them the results,” Kane said. “We follow up, we give them the results and also give them advice, options for treatment and make sure they understand (the situation).”
Kane said the state toxicologist works with the county to provide site-specific notifications when needed.
Testing still recommended
Wells at new homes are tested for some contaminants before a certificate of occupancy is issued. Orbon said people often see that testing and think there is a level of control with their groundwater, when in fact there is less control.
“Everyone in the water business is aware of this gap,” he said. “A lot of private well owners just don’t do the surveillance that occurs on a public water supply.”
Wake in 2013 began a risk-based assessment program to identify areas of the county where contamination poses a threat and do more outreach within the real estate community, on its website and with materials distributed at regional centers.
“The story is always the same: well owners should consider sampling their wells on a regular basis,” Orbon said.
Through the program, Orbon said the county will test the water quality of new wells being constructed in high-risk areas and can mark them, since Wake does regulate the installation of new wells, and repairs and abandonment of existing private wells.
The county also requires new wells within 1,500 feet of a known contaminant source to be sampled for similar contaminants.
“That kind of gives us authority to interject in the process of buying and selling a new home to check for contaminants,” Orbon said. “It’s challenging because you have a lot of wells out there, but you want to contact people where you have a greater risk.”
The county, however, does not to continue to monitor the wells that test positive for high levels of uranium.
“We are very happy to come out and take additional samples for testing, but we don’t conduct follow-up monitoring on those wells,” Kane said. “(The owners) are the operator in charge of their water system.
“We have a mandate to protect public health through our permitting program and we add to that our risk-based outreach program. That well, that water supply, is within the control of that property owner, so we really need them to partner with us for any follow-up testing. We hope people will call us and take advantage of our services, but in the end, it really is up to them.”
Dealing with uranium
For those who want to have their wells tested, the county recommends a Gross Alpha sample, a substitute for an uranium sample that identifies a number of different radiological elements like radon, radium and uranium.
If a test comes back positive for Gross Alpha, then people should pursue further testing to determine which specific contaminant they have.
For wells in the region that test positive for excessive levels of uranium, there are options to treat the water through filtration.
Two methods Orbon named were removal of ions by using water softeners, and reverse osmosis. In both cases, he said people should seek professional advice specific to their well.
Orbon does not think the Rolesville Granite will have an affect on the viability of the Little River as a potential water source for Wake County in the future, despite the fact that the watershed lies directly on top of the rock formation. After all, the long-discussed eastern Wake County reservoir would be sampled and treated regularly just like Raleigh’s current water system.
And, Orbon says, contaminants located in rocks below the water typically don’t leach out into the surface water. “It just doesn’t happen that often that you get high levels of radiological (contaminants) in surface water,” Orbon said. “The experience shows, regardless of where you locate a reservoir, these radiological contaminants don’t take (hold).”
For more information on testing wells
Visit Wake County’s well water sampling website at nando.com/40k or call the Wake County Department of Environmental Services at 919-856-7400.