As Wichita moves toward a vote Tuesday on whether to fluoridate its drinking water, three issues continue to arise in the public debate: whether commercial-grade fluoride is different than naturally occurring fluoride, whether the fluoride to be added to the water is pharmaceutical grade and whether the warning labels on toothpaste should be read as a caution against fluoridated water.
A Tennessee professor of fluorine chemistry says all fluoride ions are the same, the U.S. Centers for Disease Control says the fluoride used in water systems is actually purer than pharmaceutical grade and a Washington poison-control expert says eating a lot of toothpaste could cause gastric distress, but not from acute fluoride poisoning.
Those views are at odds with statements that local fluoridation opponents have regularly made in their campaign against an initiative that would require Wichita to increase the concentration of fluoride in its drinking water to .7 parts per million, the amount the CDC recommends as optimal for fighting tooth decay.
Natural or artificial
The natural vs. man-made debate arose after fluoride proponents argued that Dodge City hasn’t experienced unusual health impacts, despite a fluoride level more than three times the concentration that would be put in Wichita water.
Fluoride opponents countered that Dodge City’s fluoride is naturally occurring calcium fluoride, not from man-made additives containing sodium or silica.
Jaime Adcock, a professor of inorganic and fluorine chemistry with the University of Tennessee, said “fluoride ion is fluoride ion,” regardless of where it comes from.
And an anti-fluoride chemistry professor who spoke to the Sedgwick County Commission last week acknowledged that’s true.
“I think that’s where citizens make the mistake, (thinking) natural fluoride is OK, man-made fluoride is not OK,” said Paul Connett, of St. Lawrence University of New York. “That is not the issue. The issue in my view is the fluoridating chemicals that we are using are contaminated. They’re industrial grade.”
The anti-fluoride campaign brought Connett to Wichita to present its views to local officials and voters.
“My argument is … fluoride ion is bad and we shouldn’t be putting it in the water,” he said. “And if we decide to put it in the water, then for goodness sake use pharmaceutical grade or food grade, not industrial grade.”
Fluoride used in water systems, which Connett calls industrial grade, is a processed by-product obtained from separating phosphates from rock to use in fertilizers, Adcock said.
She said calcium fluoride is much less soluble than the compounds used in man-made fluoride additives, limiting the concentration in water to about 2.5 parts per million.
Fluorosilicic acid, or FSA, is the chemical most often used in community water fluoridation.
“It’s not a different kind of fluoride, it’s just a much more soluble kind of fluoride,” Adcock said. “They use it because they can administer it as a precisely concentrated solution that they drop it into a large quantity of water and mix it. (FSA) is just a less expensive source of fluoride.”
How pure is pure?
The purity of the fluoride used in water systems is primarily regulated and monitored by the NSF, a private-sector group formerly called the National Sanitation Foundation.
The purity of fluoride used in pharmaceutical products is set by a different private group, the United States Pharmacopeial Convention.
The CDC compared the group’s standards and found that NSF standards allow fewer impurities than the pharmaceutical grade.
“Pharmaceutical grading standards used in formulating prescription drugs are not appropriate for water fluoridation additives,” the CDC said in a statement. “If applied, those standards could actually increase the amount of impurities as allowed ... in drinking water.
“Given the volumes of chemicals used in water fluoridation, a pharmaceutical grade of sodium fluoride for fluoridation could potentially contain much higher levels of arsenic, radionuclides, and regulated heavy metals,” the CDC statement said.
One impurity that has garnered particular concern in Wichita is arsenic, a toxic semi-metallic element.
The Environmental Protection Agency’s maximum contaminant level for arsenic in drinking water is 10 parts per billion. The NSF standard for arsenic in fluoride additives is one part per billion, one-tenth of the EPA’s allowable level.
In a June 2012 report, NSF said its testing showed zero arsenic in 57 percent of samples it tested over a six-year period. Where detectable arsenic was found, the average concentration was .12 parts per billion and the highest was .6, well below the allowed one part per billion.
Connett questioned the findings in the report.
“What we know is there is arsenic in all these samples that have been measured and some of the arsenic levels raise to the level of one part per billion, which is one-tenth of the allowable standard, which should forbid it,” Connett said. “But the key thing is … arsenic is a known human carcinogen. We shouldn’t be adding any arsenic to the drinking water.”
Wichita can keep from adding arsenic to the water by buying arsenic-free fluoride, said Alan King, director of public works.
If fluoridation passes, the city plans to purchase the “highest quality, lowest impurity (fluoride) that’s commercially available,” he said.
Adcock also said the warning labels on toothpaste aren’t as much about fluoride as the other substances in the tube, although she acknowledged the fluoride concentration in toothpaste is much higher than in drinking water.
“They tell you not to swallow toothpaste; that’s not because of fluoride,” Adcock said. “Toothpaste is basically a surfactant (detergent) and too much toothpaste can cause diarrhea.
“If you were to eat half a tube of toothpaste, you could get mild fluoride poisoning,” Adcock added. “But you would have a terrible case of diarrhea (from the other ingredients). I’m not sure which would be worse.”
Tom Martin, a physician and associate medical director of the Washington Poison Control Center in Seattle, agreed with that analysis.
A child who eats toothpaste “might get sick from just the GI (gastrointestinal) upset,” Martin said. “One tube of toothpaste, you would not have significant fluoride toxicity from that.”
He said in cases where children do eat toothpaste, the center advises the parents to observe the child. If the child doesn’t show any symptoms, they can just stay home.
If the parents reported serious digestive symptoms, the center would advise the parents to take the child to the emergency room for observation.
Martin said acute fluoride poisoning is almost always associated with use of industrial cleaning compounds.
“Very high concentrations of fluoride can cause burns and can cause serious illness in the body,” he said.
But, he added, “We’re not talking anywhere near the levels that would be present in drinking water. We’re talking about industrial solutions.”