Combinations of fluoridation/disinfection chemicals “spike” lead levels in children’s blood and in tap water:

Neurotoxicology (2007) – “Effects of fluoridation and disinfection agent combinations on lead leaching from leaded-brass parts” – Fluosilicic acid or sodium fluoride, when combined with chloramine or chlorine, while in contact with brass fittings, can synergistically spike lead concentrations in tap water, to as high as 900 μg/L.
Toxicology (2010) – “Fluoride increases lead concentrations in whole blood and in calcified tissues from lead-exposed rats” – Fluoride co-administered with lead increases both blood lead and lead concentrations in calcified tissues in Wistar rats exposed to lead from the beginning of gestation.
Environmental Science and Technology (2006) – “Reexamination of hexafluorosilicate hydrolysis by 19F NMR and pH measurement” Common buffers don’t prevent acidic pH shifts when hexafluorosilicate is added to drinking water.
- Government of Canada (2005) – “Guidance on Controlling Corrosion in Drinking Water Distribution Systems” – Any treatment change that will have a chemical, biological or physical impact on the distributed water should be carefully monitored in the distribution system. Lead corrosion and lead levels are easily influenced by small changes in the quality of the water distributed. Water with pH significantly under 7.5 is strongly correlated with higher lead levels at the tap. A pH exceeding 9.5 can lead to an increase in lead solubility. Effects of fluoridation chemicals not analyzed.
- Water Research (2013) – “Impact of treatment on lead released from full and partially replaced lead service lines” – Orthophosphate reduces lead release from undisturbed lead service lines by 64%. For lead service lines partially replaced with copper, lead concentrations were unchanged by phosphate dosing at moderate flow (103 ± 265 vs 169 ± 349 μg/L) and were increased to very high levels when sampled at high flow rates (1001 ± 1808 vs 257 ± 224 μg/L). Effects of fluoridation chemicals not analyzed.
- Journal of Environmental Science and Health – Toxic/Hazardous Substance Environmental Engineering (2009) – “Corrosion control in water supply systems: effect of pH, alkalinity, and orthophosphate on lead and copper leaching from brass plumbing” – Orthophosphate up to 70% effective with pH > 7.5. Lead leaching increases with low alkalinity and hardness levels and a moderately alkaline pH. Effects of fluoridation chemicals not analyzed.
- Web Editor Analysis: Flint’s tap water, currently from Detroit, needs higher lead concentration reductions than orthophosphate provides, even with ideal water chemistry. The Safe Water Drinking Act’s target range for water chemistry (see Page 2-6), doesn’t maximize the typical corrosion control chemicals’ effectiveness. Orthophosphate’s effective range occurs with water pH above 7.5, but far lower pH ranges are allowed under the Safe Water Drinking Act and Detroit Water and Sewerage Department’s “goals”. Even with ideal chemistry, orthophosphate is only 70% effective at reducing lead leaching from standard brass plumbing components. Flint’s water needs even larger lead concentration reductions.
Neurotoxicology (2007) – “Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals” – Living in communities with silicofluoride treated water correlates with elevated lead in tap water and children’s blood, based on testing 400,000 children.
Neurotoxicology (2000) – “Association of silicofluoride treated water with elevated blood lead” – Fluoridation compounds correlate with elevated blood lead concentrations in 150,000 children, ages 0 and 6 years old (i.e., above 10 microg/dL), in old housing.
Environmental Health Perspectives (2007) – “Changes in Blood Lead Levels Associated with Use of Chloramines in Water Treatment Systems” – Changes in water chemistry cause interactions with additives such as coagulants or fluoridation agents that may remove lead dioxide scales originally formed during decades of chlorine-based disinfection.
Environmental Health Perspectives (2006) – “Blood lead concentrations in children and method of water fluoridation in the United States, 1988-1994” – Fluorosilicates correlate with blood levels in occupants of pre-1946 houses.
Environmental Health (2015) – “Exposure to fluoridated water and ADHD prevalence among children and adolescents in the United States: an ecological association” – Silicofluoride-treated communities are associated with elevated lead venous blood levels along with a significantly increased risk of developing ADHD. A 1% increase in artificial fluoridation prevalence in 1992 was associated with approximately 67,000 to 131,000 additional ADHD diagnoses from 2003 to 2011.
International Journal of Environmental Studies (1999) – “Water treatment with silicofluorides and lead toxicity” – Water treatment with siliconfluorides correlates with increased cellular uptake of lead.
Science of the Total Environment (1997) – “Lead and fluoride content in human bone and hair in the Gdańsk region” – Positive correlation between the fluoride and lead contents in bones and the age of the investigated persons.
Public Health Reports (2005) – “Reducing lead exposure from Drinking Water: Recent History and Current Status” – 15% of water samples drawn from New York City residences had lead concentrations above 10 μg/L. Note that New York’s water:
- Has been fluoridated since 1964.
- Uses hydrofluorosilicic acid, with orthophosphate to reduce corrosion.
The Frederick Post (Maryland, 2/2/94) – “Lead levels in Thurmont water drop” – After halting hydrafluorosilic acid fluoridation in 1992, tap water lead levels dropped from 50 times the EPA limit to acceptable levels.
Tacoma Public Utilities (12/2/92) – “Memorandum” – Tap water lead level plummets after suspending fluoridation.
News & Observer (North Carolina 5/18/05) – “Water treatment process called potential risk” – A combination of chloramines and fluorosilicic acid, especially with extra amounts of ammonia, increases lead leaching… About 300 customers had water tested after notice of the lead was issued in November, and levels were high in 25 percent of the houses.
City of Thunder Bay, Ontario (2009) – “The effects of fluoridating agents on the chemistry of Thunder Bay drinking water” – Hydrofluorosilicic acid increases lead leached from coupons fabricated from lead pipe by a factor of 2.6 times the leaching that occurs in non-fluoridated tap water.
Environmental Health Perspectives (2007) – “Chloramine Catch: Water Disinfectant Can Raise Lead Exposure” Children’s blood lead levels increase in Wayne County, North Carolina, after switching from chlorine to chloramine for disinfection. Need to test full range of water treatment chemicals, including fluoride, to quantify their effects on leaching lead.
Journal of the American Water Works Association (2010) – “Lead-contaminated water from brass plumbing devices in new buildings” – New buildings at University of North Carolina – Chapel Hill water had lead concentrations up to 100 μg/L. Chapel Hill’s water is treated with phosphates for corrosion control, chloramine for disinfection, and hydrofluosilicic acid for community-wide dental protection.
- See page 14 for Chapel Hill’s water treatment chemicals
Journal of the American Water Works Association (2005) – “Lead leaching from inline brass devices: A critical evaluation of the existing standard” – A carefully controlled orthophosphate solution can significantly reduce lead leaching from brass into tap water, but significantly increases copper leaching into the tap water. Leaching effects of fluoridation chemicals were not tested.
Medical News Today (2005 Press Release) – “Fluoride Chemicals Leach Lead Into Water Supplies” – The combination of chloramines and fluorosilicic acid causes a 3 to 4-fold increase in the amount of lead that leaches into water.
Journal of Environmental and Public Health (2013) – “Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride” – Silicic acid in an alkaline pH may leach lead salts from lead-based plumbing, which does not occur with sodium fluoride.
Water Research (2012) – “Understanding how brass ball valves passing certification testing can cause elevated lead in water when installed” – New brass valves that have passed NSF leach tests for leaching lead have been found to cause drinking water lead concentrations above 300 μg/L in new buildings around the world.
Journal of Environmental Health (2002) – “An assessment of lead exposure potential from residential cutoff valves” – Most brass valves contain 5% to 7% lead, and represent a significant, widespread, and needless source of lead exposure to the U.S. public.
Environmental Science Technology (2006) – “Evidence that monochloramine disinfectant could lead to elevated Pb levels in drinking water” – Monochloramine dissolves protective lead film inside pipe, increasing lead levels in drinking water.

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