Tamara Rubin, the Sellwood mom who earned a national reputation as a crusader against lead poisoning, is taking on a new target: fluoridated water.
Rubin says the number of children poisoned by lead could double or even quadruple if Portlanders vote next month to fluoridate the city’s Bull Run water supply, based on studies showing fluoride causes more leaching of lead into the water system and enables more lead to be absorbed by the human body.
It could be a potent argument if it resonates among voters, since the major benefit of fluoridating water is improving children’s health by reducing cavities.
However, like nearly every aspect of the fluoridation controversy, the link between lead and fluoride is hotly debated by dueling scientists and advocates on both sides.
Rubin, executive director of the Lead Safe America Foundation and producer of an upcoming video documentary on the hazards of lead contamination, notes that many older Portland homes and schools suffer from high lead in the water due to old plumbing.
“I sent a letter to the city, if they fluoridate the water, I’ll have to sue them for poisoning my children,” Rubin says, “because they drink water in the schools.”
David Shaff, administrator of the Portland Water Bureau, says his staff have read the dueling scientific studies on lead and fluoride, and they defer to health experts. Shaff notes that Multnomah County Health Department, the Oregon Health Authority, the U.S. Centers for Disease Control and “every reputable health organization” endorses fluoridated water as a health benefit.
Kip Duchon, the CDC’s national fluoridation engineer, says there was a period several years ago when the reputed link between lead and fluoride got a lot of scientific attention, but those concerns have since been allayed.
“There’s a lot of information that ends up never going away, even after it’s been proven to be incorrect,” Duchon says. “I think it’s settled science.”
Fluoride critics and many scientific researchers disagree.
The studies that first set off alarm bells were 1999 and 2000 research reports led by Roger Masters, emeritus Dartmouth College professor at the Institute for Neuroscience and Society; and Myron Coplan of Intellequity Technology Services. They pored over federal blood tests administered to more than 1 million children and found those living in communities with fluoridated water had nearly three times the rate of elevated lead levels as those in unfluoridated communities.
Nearly 2 percent of the Massachusetts children under the age of 6 had 10 milligrams or more of lead per deciliter, a level of concern then used by the CDC. About 0.75 percent of children in non-fluoridated communities had lead levels that high.
The researchers also found that black youth had a much higher rate of high lead levels than white youth.
Lead poisoning has been linked to a host of physical and emotional problems — particularly among children — including lowered IQ, attention deficit disorder, learning disabilities, even more violent crime.
Rubin argues that no amount of lead is safe, and has long contended that lead levels of 2 milligrams per deciliter or higher should be a gauge for concern. She received some validation last May, when the CDC lowered its lead standard from 10 to five milligrams per deciliter. By that measure, far more children in the Masters and Coplan studies had alarming lead levels.
In response to the Masters and Coplan studies, federal officials commissioned a report by Edward Urbansky and Michael Schock, scientists at a U.S. Environmental Protection Agency research laboratory for water treatment technology.
In their published paper, Urbansky and Schock noted the concern that lead in drinking water is more “bioavailable” in the human body, but dismissed the possibility that fluoride adds to that effect.
“We feel strongly that there is no scientific justification for asserting that water fluoridation chemicals can have any (quantifiable) impact on human health via lead exposure,” they concluded. Masters and Coplan’s findings, they wrote, were “the result of an unfortunate coincidence.”
A 2006 published study led by Mark Macek of the Baltimore College of Dental Surgery at the University of Maryland sought to explain that coincidence. The researchers re-examined Masters and Coplan’s work and found there was a close correlation between the age of the children’s homes and the likelihood of elevated lead levels. Macek’s team, using a lower lead level of 5, found no differences in lead levels between children in cities with and without fluoridation, once the age of the home was considered.
“The fluoridated cities were old cities with old pipes and the non-fluoridated cities were new cities with new pipes,” Duchon says.
It’s well known that older homes are more likely to have leaded paint, since it was banned in U.S. homes in 1978, as well as lead in their plumbing systems. In Portland, lead was commonly used in copper solder in water pipes, Shaff says, especially among homes plumbed from 1970 to 1985.
But the new studies didn’t quell further research into the fluoride-lead connection.
In 2007, researchers led by Richard Maas at the University of North Carolina-Asheville’s Environmental Quality Institute published a study showing that commonly used fluoridation chemicals, in combination with chloramines used to disinfect city water supplies, resulted in more releases of lead into piped water. Portland Water Bureau treats its water with chloramines.
Duchon says the Maas study had a fatal flaw, and that fluoride actually tends to limit corrosion inside water pipes.
The CDC website notes that lead may leach into water, but says it’s not due to the presence of fluoridation chemicals. “Water fluoridation will not increase water corrosion or cause lead to leach (dissolve) from pipes and household plumbing fixtures,” the agency says.
In 2010, a published study led by Rosangela Sawan of the School of Dentistry at the University of Sao Paulo in Brazil tested the impact of fluoride mixed with lead on baby rats. The researchers found rats exposed to a combination of both substances absorbed 1.7 to three times more lead in various body parts than those who were exposed to lead without the fluoride.
That study is being used by people like Rubin to argue that fluoride makes lead more bioavailable in the human body.
Studies cited by both sides in the debate have their limitations — and none have been definitive — says Chris Neurath, research director of the American Environmental Health Studies Project, which counts the Fluoride Action Network, the nation’s leading anti-fluoridation group, as one of its projects.
But Neurath says to argue, as Duhon and other fluoride supporters do, that the issue is settled and there’s nothing to worry about, is wrong. “There’s enough evidence to say this is of concern,” he says. “I’d be very concerned if someone is protecting my health with that attitude.”