“Raising Environmental Justice Concerns” – Hispanic/Latino Communities More Likely to Receive Excessive Fluoride in Water
Analyzing an Environmental Protection Agency database from 2006-2011, researchers from Emory University, Columbia University and UC San Francisco have found that Hispanic/Latino communities are more likely to receive water with excessive amounts of fluoride, compared to that received by other communities.
Summarizing their report, they write, “We found significant inequalities in community water systems (CWS) fluoride concentrations by county sociodemographic characteristics, including by racial/ ethnic composition, further raising environmental justice concerns for these communities. Compared to other CWSs, those serving Semi-Urban, Hispanic communities and communities in the Southwest were most likely to exceed 700 µg/L (current USPHS optimal concentration), 1500 µg/L (WHO guidance level), and 4000 µg/L (US EPA’s MCL). Our finding that higher proportions of Hispanic/Latino residents were associated with higher average county-level CWS fluoride concentrations adds to a growing body of evidence that Hispanic/Latino communities are disproportionately exposed to higher concentrations of regulated inorganic contaminants in public drinking water, including arsenic, uranium, nitrates, chromium, and selenium. For fluoride, this county-level association remained significant even after adjustment for the percent of public water that was manually fluoridated, indicating that naturally occurring fluoride in groundwater sources may be driving higher concentrations for CWSs serving largely Hispanic/Latino communities. In general, inequities in the natural (e.g. hydrogeology, climate), built (e.g. water infrastructure, groundwater reliance), and sociopolitical (e.g. structural racism, social and political vulnerability) environments underlie disparities in public drinking water exposures across the US.”
In a sign that the evidence of fluoride’s neurotoxicity is becoming more widely appreciated in scholarly research, the authors note, ““Although the US Centers for Disease Control and Prevention (CDC) considers fluoridation of community water systems (CWSs) to be a major public health achievement responsible for reducing dental disease, recent epidemiologic evidence suggests that chronic exposure to population-relevant levels of fluoride may also be associated with adverse child neurodevelopmental outcomes,” write the authors.
“The current study adds to a growing body of evidence finding higher inorganic contaminant concentrations in CWSs that rely on groundwater, are located in the Southwest, and serve communities with high proportions of Hispanic/Latino residents. Further studies at higher spatial resolution within the Southwest are needed to evaluate whether racial/ethnic inequities in fluoride concentrations differ within this region. Regardless, additional technical, financial, and regulatory support is needed to reduce inorganic contaminant concentrations in CWSs serving these communities, especially for other inorganic contaminants such as arsenic and uranium which have no beneficial role in protecting human health,” they conclude.
Wistar rats given sodium fluoride in water displayed a dose- and time-dependent increase in a variety of biological molecules of the kidney’s proximal renal tubules that include microRNAs (MiRNAs) associated with cancer, according to a new report.
The authors found “a transition from renal epithelium to pathologic tissue after fluoride exposure.”
“Fluoride is rapidly distributed through the blood and accumulates mainly in bones and teeth. However, it also bioaccumulates in high concentrations in soft tissues such as the aorta, pineal gland, thyroid, and kidneys. Fluoride is excreted mainly through the kidneys. Even though fluoride passes freely through the glomerulus, a fraction is reabsorbed by proximal tubules resulting in high exposure to this xenobiotic,” note the authors from the Mexico Polytechnic Institute, reporting in Chemico-Biological Interactions on April 27.
“The miRNAs associated with the cancer pathway induced by fluoride include miRNAs that control cell cycle, DNA stability, and cell death through the downregulation of Cyclins, p53, and Bcl2 families. Our MiRNA analysis suggests that sub-chronic exposure to fluoride could be able to promote a neoplastic effect in kidneys,” write the authors.
They consider the prospect that the molecular perturbations they found may be a cellular defense mechanism, noting, “We must consider that the expression of miRNAs involved in cell proliferation could also be due to repair after exposure to fluoride.”
A recent study of the sociodemographic characteristics of fluoridated water systems reports that nearly three million residents of the USA are receiving water with fluoride levels in excess of the World Health Organization’s recommended maximum level of 1.5 mg/L.
The authors of the report in the Journal of Exposure Science and Environmental Epidemiology also estimate that more than 20.5 million people received water from systems that had a six-year average fluoride level in excess of the US Department of Health and Human Services recommended concentration of 0.7 mg/L.
They also noted an anomaly in the percentage of community water systems (CWS) manually fluoridating the water.
“Out of 25,617 CWSs voluntarily reporting fluoridation information to the CDC, only 6130 (24%) reported manual fluoridation, which is much lower than EPA’s estimate that approximately 12,341 CWSs manually fluoridated their water in 2012, report the authors, from several US universities.
The authors note a deficiency of Centers for Disease Control and Prevention (CDC) reporting, writing, “To our knowledge, a nationally representative database of CWS fluoride concentration estimates that can be readily linked to US epidemiologic cohorts for further study is not publicly available.”
The endless quest to find low-cost methods of removing fluoride from drinking water in areas of endemic fluorosis, which affects 200 million people around the world, has led investigators from the South China Agricultural University to focus on Bidens pilosa, a plant from the daisy family.
Bidens, meaning “two teeth,” is a widely distributed genus of fast growing weeds. The authors of the new report in Environmental Technology & Innovation used the plant material to produce biochar with added iron, lanthanum and cerium. They found that the biochar removed fluoride from water at a rate of 192.79 mg/g in an hour.
They note their technique addresses the problem of fluoride in water (“a threat to human health and it urgently needs to be eliminated”) while removing an invasive weed from the landscape.
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