WILMINGTON, NC (WECT) - Fluoride will no longer be added to drinking water treated at the Richardson Nano Groundwater Treatment Plant in New Hanover County until an investigation into why levels of the chemical spiked on Wednesday is complete.
According to CFPUA officials, a "do not drink" alert was issued after crews discovered fluoride levels at the plant were at 8 mg/L, which is twice the EPA's upper legal limit and more than 10 times the recommended level of 0.7 mg/L set by the U.S. Public Health Service.
The "do not drink" alert and a subsequent boil water advisory have been lifted and the water is now safe to drink.
Frank Styers, chief operations officer of CFPUA, said in a phone call Thursday that he is conducting a "deep-dive" investigation into what caused the water treatment plant to overfeed fluoride, which is normally added to prevent tooth decay in the community.
"We have disabled some equipment," said Styers. "We have a pretty good idea of what caused it, but the investigation is ongoing."
Styers said he wants to complete CFPUA's investigation before releasing details about whether the fluoride overfeed was caused by human or mechanical error.
When asked about how long the investigation will take, Styers was not able to provide an estimate.
"After we got our system back up and running yesterday, we did start to investigate at the plant the mechanical equipment," said Styers. "We need to look at some calculations…we haven't been able to draw any conclusions yet."
Several customers reached out to WECT and asked if CFPUA would reimburse them for bottled water they had to purchase as a result of the fluoride spike. Styers says he does not have an answer to that question right now.
How long were fluoride levels too high in drinking water?
Styers said CFPUA is currently working on a timeline to determine how long fluoride levels were elevated, but he could not provide an estimate right now.
The spike was first detected at 2 a.m. at the clear well at the plant, according to Pat Kusek, chair of CFPUA's Board of Directors.
Fluoride levels returned to below 2 mg/L at 9 a.m., according to CFPUA's Director of Engineering Carel Vandermeyden.
"We take samples every four hours when the plant is in operation," said Vandermeyden in an interview yesterday.
What do scientific experts say about fluoride in tap water?
Dr. David Hill, a pediatrician based in Wilmington, said drinking water with fluoride levels at the concentration detected is unlikely to cause harm to humans.
"Yesterday's elevation was not dangerous to anybody because it was so short in duration," said Hill. "Fluoride in water is a very, very good thing for preventing cavities as long as it's the right amount."
"Now if you did that every day for years, it could cause some problems," Hill explained. "But for a few hours over the course of one day, I'm not worried for anybody."
Fluoride added to tap water has been proven to protect teeth from decay, according to David Howard, assistant health director with New Hanover County.
"Fluoride helps rebuild and strengthen the tooth's enamel, and so it keeps teeth strong with frequent and consistent contact with low levels of fluoride," Howard wrote in an email.
Too much fluoride or not enough of the compound in drinking water can be harmful, according to the World Health Organization.
"Fluoride intake has both beneficial effects – in reducing the incidence of dental caries – and negative effects – in causing enamel and skeletal fluorosis following prolonged high exposure," writes the WHO. "The ranges of intakes producing these opposing effects are not far apart."
The Centers for Disease Control and Prevention (CDC) fully supports regulated fluoride in tap water to prevent tooth decay, writing that the safety and effectiveness have been shown by several scientific and public health organizations using study reviews and panels.
"Experts have weighed the findings and quality of available evidence and concluded that there is no association between water fluoridation and any unwanted health effects other than dental fluorosis," according to the CDC.
Dental fluorosis is the appearance of white spots and pitted surfaces on teeth.
The North Carolina Department of Health and Human Services also supports fluoride programs in tap water for reducing tooth decay in a safe way.
"The overwhelming weight of credible scientific evidence indicates that fluoridation of community water supplies is safe," the NCDHHS writes. "In the years before community water fluoridation, virtually every child grew up with severe and widespread tooth decay."
A review study in 2012 found the possibility that too much fluoride over time can have negative consequences on a child's brain development.
But the American Academy of Pediatrics refutes this study's findings, saying there are too many errors in the science quality to prove any conclusive link between fluoride levels and lower IQ.