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In a recent article in the journal NeuroToxicology, a research team led by Roger D. Masters, Dartmouth College Research Professor and Nelson A. Rockefeller Professor of Government Emeritus, reports evidence that public drinking water treated with sodium silicofluoride or fluosilicic acid, known as silicofluorides (SiFs), is linked to higher uptake of lead in children.
Sodium fluoride, first added to public drinking water in 1945, is now used in less than 10% of fluoridation systems nationwide, according to the Center for Disease Control's (CDC) 1992 Fluoridation Census. Instead, SiF's are now used to treat drinking water delivered to 140 million people. While sodium fluoride was tested on animals and approved for human consumption, the same cannot be said for SiFs.
Masters and his collaborator Myron J. Coplan, a consulting chemical engineer, formerly Vice President of Albany International Corporation, led the team that has now studied the blood lead levels in over 400,000 children in three different samples. In each case, they found a significant link between SiF-treated water and elevated blood lead levels.
"We should stop using silicofluorides in our public water supply until we know what they do," said Masters. Officials at the Environmental Protection Agency have told Masters and Coplan that the EPA has no information on health effects of chronic ingestion of SiF-treated water.
In their latest study published in a special December 2000 issue of NeuroToxicology , Masters, Coplan and their team analyzed data on blood levels from more than 150,000 children ages 0 to 6. These tests were part of a sample collected by the New York State Department of Children's Health, mostly from 1994 to 1998 in comparable non-fluoridated and SiF-treated public drinking water in communities with populations of similar size. Socio-economic and demographic risk factors for high blood lead were also considered using information from the 1990 U.S. Census. The researchers found that the greatest likelihood of children having elevated blood lead levels occurs when they are exposed both to known risk factors, such as old house paint and lead in soil or water, and to SiF-treated drinking water.
"Our research needs further laboratory testing," added Masters. "This should have the highest priority because our preliminary findings show correlations between SiF use and more behavior problems due to known effects of lead on brain chemistry." Also requiring further examination is German research that shows SiFs inhibit cholinesterase, an enzyme that plays an important role in regulating neurotransmitters.
"If SiFs are cholinesterase inhibitors, this means that SiFs have effects like the chemical agents linked to Gulf War Syndrome, chronic fatigue syndrome and other puzzling conditions that plague millions of Americans," said Masters. "We need a better understanding of how SiFs behave chemically and physiologically."
Currently, a bill before the New Hampshire House of Representatives would impose more stringent testing on fluoridating chemicals added to public drinking water. On March 7, 2001, Masters and Coplan testified in favor of the bill, HB 754, The Fluoride Product Quality Control Act, at a public hearing. Masters contends that bill's requirement for testing the silicofluorides is vital but needs to be complemented by further research on neurotoxicity and behavior.
Masters and Coplan note that their recent studies contain the most extensive empirical evidence of the health and behavioral costs of these chemicals. "If further research confirms our findings," Masters added, "this may well be the worst environmental poison since leaded gasoline."
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