© 2025 American Dental Association l 75
Fluoridation Facts
It should be noted that approximately 95% of the primary sources of adult lead exposure are
occupational.342 In general, adult BLLs have continued to decline over recent decades due largely
to improved prevention measures in the workplace and changes in employment patterns.342
Acidity of Drinking Water and EPA Research
Those opposed to water fluoridation sometimes claim that there is an increase in acidity when fluoride is
added to water and that the acidic water in the local water system leaches lead from pipes and fixtures.
The process of adding fluoride to water has minimal impact on the acidity or pH of drinking water. Under
some water quality conditions, a small increase in the acidity of drinking water that is already slightly
acidic can be observed after treatment with alum, chlorine, fluorosilicic acid, or sodium fluorosilicate.
In such cases, additional water treatment to adjust the pH to neutralize the acid in water distribution
systems is standard practice in water plants.343 Water facilities typically maintain a pH of between
7.0 and 8.0 as standard practice so the water leaving the plant is slightly alkaline and non-acidic.344
Despite this information, opponents continue to exploit unfounded claims that fluoridation can lead
to an increased uptake of lead by children. A 1999 study345 charged that fluorosilicic acid and sodium
silicofluoride did not disassociate completely when added to water systems and could be responsible
for lower pH (more acidic) levels of drinking water, leaching lead from plumbing systems and increasing
lead uptake by children. In response to the study, scientists from the EPA reviewed the basic science
that was the foundation for the claim that silicofluorides leach lead from water pipes and found that
many of the chemical assumptions made in the original ecological study were scientifically unjustified.346
Fluoride additives do disassociate very quickly and completely release fluoride ions into the water. The
research from the 1999 study was inconsistent with accepted scientific knowledge, and the authors of
that study failed to identify or account for those inconsistencies. The EPA scientists discounted the 1999
study and said there were no credible data to suggest any link between fluoridation and lead. Overall,
the EPA scientists concluded that “…no credible evidence exists to show that water fluoridation has any
quantifiable effects on the solubility, bioavailability, bioaccumulation, or reactivity of lead compounds.”346
In 2006, researchers at the University of Michigan used sophisticated laboratory techniques to
confirm the EPA’s theoretical predictions that hexafluorosilicate completely hydrolyzed (broke down)
when added to water, separating into free fluoride ions and silica ions.347
43. Does drinking water fluoridated at recommended levels cause
Alzheimer’s disease?
Answer
No. The best available scientific evidence shows that optimally fluoridated water does not cause
and has not been shown to have an association with Alzheimer’s disease.
Fact
Scientists believe the causes of late-onset Alzheimer’s disease, the most common form of the
disease, include a combination of age-related brain changes and genetic, lifestyle, and environmental
factors. The importance of these factors in increasing or decreasing the risk of developing Alzheimer’s
disease differs from person to person. Early onset Alzheimer’s disease is less common (fewer than
10% of Alzheimer’s disease cases), with the first signs of the disease typically appearing between an
individual’s 30s and mid-60s. It is believed to be caused primarily by gene changes passed down from
parent to child.348
Fluoridation Facts
It should be noted that approximately 95% of the primary sources of adult lead exposure are
occupational.342 In general, adult BLLs have continued to decline over recent decades due largely
to improved prevention measures in the workplace and changes in employment patterns.342
Acidity of Drinking Water and EPA Research
Those opposed to water fluoridation sometimes claim that there is an increase in acidity when fluoride is
added to water and that the acidic water in the local water system leaches lead from pipes and fixtures.
The process of adding fluoride to water has minimal impact on the acidity or pH of drinking water. Under
some water quality conditions, a small increase in the acidity of drinking water that is already slightly
acidic can be observed after treatment with alum, chlorine, fluorosilicic acid, or sodium fluorosilicate.
In such cases, additional water treatment to adjust the pH to neutralize the acid in water distribution
systems is standard practice in water plants.343 Water facilities typically maintain a pH of between
7.0 and 8.0 as standard practice so the water leaving the plant is slightly alkaline and non-acidic.344
Despite this information, opponents continue to exploit unfounded claims that fluoridation can lead
to an increased uptake of lead by children. A 1999 study345 charged that fluorosilicic acid and sodium
silicofluoride did not disassociate completely when added to water systems and could be responsible
for lower pH (more acidic) levels of drinking water, leaching lead from plumbing systems and increasing
lead uptake by children. In response to the study, scientists from the EPA reviewed the basic science
that was the foundation for the claim that silicofluorides leach lead from water pipes and found that
many of the chemical assumptions made in the original ecological study were scientifically unjustified.346
Fluoride additives do disassociate very quickly and completely release fluoride ions into the water. The
research from the 1999 study was inconsistent with accepted scientific knowledge, and the authors of
that study failed to identify or account for those inconsistencies. The EPA scientists discounted the 1999
study and said there were no credible data to suggest any link between fluoridation and lead. Overall,
the EPA scientists concluded that “…no credible evidence exists to show that water fluoridation has any
quantifiable effects on the solubility, bioavailability, bioaccumulation, or reactivity of lead compounds.”346
In 2006, researchers at the University of Michigan used sophisticated laboratory techniques to
confirm the EPA’s theoretical predictions that hexafluorosilicate completely hydrolyzed (broke down)
when added to water, separating into free fluoride ions and silica ions.347
43. Does drinking water fluoridated at recommended levels cause
Alzheimer’s disease?
Answer
No. The best available scientific evidence shows that optimally fluoridated water does not cause
and has not been shown to have an association with Alzheimer’s disease.
Fact
Scientists believe the causes of late-onset Alzheimer’s disease, the most common form of the
disease, include a combination of age-related brain changes and genetic, lifestyle, and environmental
factors. The importance of these factors in increasing or decreasing the risk of developing Alzheimer’s
disease differs from person to person. Early onset Alzheimer’s disease is less common (fewer than
10% of Alzheimer’s disease cases), with the first signs of the disease typically appearing between an
individual’s 30s and mid-60s. It is believed to be caused primarily by gene changes passed down from
parent to child.348
