BRANDON, S.D. (KSFY) - Health concerns about radium in the water continue to boil over in Brandon.
"Radium is considered a carcinogen by the EPA and we know that levels of exposure to carcinogens carry some risk of cancer development," Dr. Alexis Tempkin, a toxicologist with the Environmental Working Group said.
California's Public Health recommendation -- which is included with the Environmental Protection Agency's guidelines -- says the toxicity of radium has been known since the 1920s. Tempkin said any exposure carries risk.
"We know that as the level of exposure goes down, or the concentration decreases, so does the risk but it never fully goes away," Tempkin said.
Tempkin said it's also a concern for women who are pregnant and young children.
"This is especially important when there’s exposure to a developing fetus, a pregnant woman or a young child when they are specifically vulnerable and susceptible to the effects of radium and carcinogens," Tempkin said.
The EPA put cap limits on the levels of radioactive elements in water, under the authority of the Safe Drinking Water Act (SDWA). One of the tests used to measure radioactivity is called Gross Alpha. Brandon recently installed a new system, called an HMO, or hydrous manganese oxide, to filter it out.
"The HMO is a slurry, it basically discharges right into the stream of the water and mixed," Jon Brown, president of Stockwell Engineers, the City of Brandon's engineer. "Then the radium -- the gross alpha -- basically have a tendency to attract to that."
Radioactive particles are too tiny to be removed on their own. The HMO attracts the radium particles with the manganese oxide -- sticking together -- to make them big enough to be caught on a filter.
Brown said once the radium is filtered out, the filter is removed and backwashed. The question homeowners want an answer to -- where does the backwash from that filter -- with the gross alpha attached to it-- go?
"They go into the backwash basin," Brown said. "We're able to reclaim about 80 to 90 percent of that but then about eight to 10,000 gallons a day gets discharged into the sewer system."
Brown said those gallons that are discharged into the sewer system are sent to the City of Sioux Falls for wastewater treatment.
KSFY News reporter Erika Leigh asked Brown whether backwashing and reclaiming the water again makes the concentration of the gross alpha higher in the water.
Leigh asked, "Backwashing and refiltering it back through -- does that increase the concentration of the gross alpha attached to the HMO particles?"
"To the particles, yes. As you continue to backwash that filter, obviously that'll end up back in the backwash basin," Brown said. "You take off the top, the water comes back through the plant and is treated and in ... always as ..."
"The city of Brandon has been very good at maintaining the water quality in Brandon and making sure it's always been discharged and distributed and discharged in the system within compliance," Brown said.
The most recent results from the South Dakota Department of Natural and Environmental resources shows the city is in compliance with a gross alpha measure of 10.2 pCi/L. The maximum contaminant level set by the EPA is 15, but the California Public Health guideline goal is zero.
"Radium exposure is associated with a rare type of bone cancer called osteosarcoma and this association was first established in workers who were exposed to radium during their jobs," Tempkin said. "So when radium is ingested it acts – similar to calcium – and deposits in the bone – so that's why it's been associated specifically with a bone cancer."
The message is clear as you drive through Brandon -- signs are displayed in many front yards that say, "No amount of radium is safe in our water." They want to see those numbers even lower.
Many are concerned about one well in particular -- Well No. 7 -- which was purchased from Sioux Falls several years ago. In a 2015 report titled "Well 7 Pumping and Redevelopment" by Stockwell Engineers, the gross alpha levels were tested after an hour of pumping, 23 hours of pumping and 32 hours of pumping.
After one hour, the raw water in the well tested at 23.3 pCi/L, after 23 hours it was 27.5 pCi/L and after 32 hours it was 26.7.
The combined radium levels (radium-226 and radium 228) were 21.54 pCi/L, 23.37 and 20.64, respectively.
Back in September, Brandon City Administrator Bryan Read told Leigh the city knew the well had high radium levels.
"We know that it had radium in it, we knew that all along," Read said.
Whether that well has been tied into the city's distribution system is the concern among homeowners.
Leigh asked Brown if it has ever been connected and run through the city's water treatment plant.
"Well 7 is on," Brown said. "I mean, it is not connected to the system OK. It is connected to the system but its with a valve that's shut off. We have never run it through the system.
"It's never been run through the system. Whenever we have done any testing it's been pulled out of basically the well itself, not necessarily through the distribution systems." Brown said. "So it hasn't, Well 7 has not been through the plant at all."
The city has a water supply issue too and because it says the radium issue is handled, it wants to begin using Well No. 7. That well is projected to increase the city's water supply by about 2 million gallons a day, according to the 2013 Comprehensive Water System report released by Stockwell Engineers.
So what are Brandon's options? Brown said his recommendation hasn't changed since that report was released four years ago.
"There are three different rural water systems in the area -- regional systems -- the City of Sioux Falls, MCWC [Minnehaha County Water Corporation] and Lewis and Clark," Brown said.
"MCWC is basically in town and so that would be the closest connection and they would be the logical one from a cost standpoint," Brown said. "Our recommendation has been to connect to MCWC because of the close proximity to Brandon and the conversations that we've had with them in the past."
This is part one of a two-night series. Tune into KSFY News at 10 on Tuesday, Feb. 6 for part two. We'll check in with a nearby community that just won an award for the best tasting water in the state, plus what's next for Brandon.