Experts find increased risk of neurotoxicity at 0.2 milligram per liter Fluoride

 

Experts find increased risk of neurotoxicity at 0.2 milligram per liter Fluoride

            A loss of one IQ point can be expected in children when their pregnant mothers are exposed to as little as 0.2 milligram per liter of fluoride in drinking water, less than one-third of the amount that is deliberately added to water supplies, according to a new report by Canadian, Mexican and US researchers published in Risk Analysis. 

            Based on an analysis of two cohort studies in Mexico and Canada, the group established a benchmark dose of 0.2 mg/L. A benchmark dose is that concentration that will produce a predicted response. 

“The Environmental Protection Agency’s maximum contaminant level goal (MCLG) of 4.0 mg/L for fluoride in drinking water was first set in 1985 to protect against chronic fluoride toxicity in the form of crippling skeletal fluorosis. In 2006, the U.S. National Research Council

(NRC) concluded that fluoride may adversely affect the brain. Since then, a substantial number of cross-sectional studies, mostly in communities with chronic fluoride exposure, have shown lower cognitive performance in children growing up in areas with higher fluoride concentrations in drinking water,” wrote the authors. 

“For the purpose of identifying safe exposure levels, regulatory agencies routinely use benchmark dose (BMD) calculations. As long recognized, fluoride is not an essential nutrient, and dose-dependent toxicity can therefore be considered monotonic,” meaning the response increases with increasing dose, write the authors. 

“Given the ubiquity of fluoride exposure, the population impact of adverse effects from fluoride may be even greater than for other toxic elements like lead, mercury, and arsenic. Adverse effects of the latter trace elements are associated with blood concentrations that are about 100-fold lower than the serum-fluoride concentration that corresponds to the benchmark concentration,” write the authors. 

Grandjean, P., Hu, H., Till, C., Green, R., Bashash, M., Flora, D., Tellez-Rojo, M.M., Song, P.X.K., Lanphear, B. and Budtz-Jørgensen, E. 2021. A benchmark dose analysis for maternal pregnancy urine-fluoride and IQ in children, Risk Analysis, in press.