Based on a nationwide survey of 25 unnamed water utilities, scientists found traces of the herbicide metolachlor, for instance, a pesticide commonly applied to conventional corn, soy, cotton, safflower, potato and other crops, as well as the heavy metal strontium, which is linked to causing bone problems. Other chemicals identified include so-called perfluorinated compounds like perfluorooctanoic acid (PFOA), which numerous scientific studies have found can cause thyroid disease and various types of cancer.
"Traces of 18 unregulated chemicals were found in drinking water from more than one-third of U.S. water utilities in a nationwide sampling," reports Environmental Health News (EHN). "Included are 11 perfluorinated compounds, an herbicide, two solvents, caffeine, an antibacterial compound, a metal and an antidepressant."
More than 250 potential hazardous compounds detected in tap water
Among the 25 water samples, more than 250 chemicals, bacteria, viruses and microbes were identified, but only 134 of these were detected in treated drinking water. As many as eight of the treated water samples collected contained upwards of 113 chemicals. According to the researchers, water samples were taken from a range of water utilities, including both large and small plants and plants using varying treatment technologies.
"The good news is the concentrations are generally pretty low," stated Dana Kolpin, a research hydrologist from USGS who helped work on the study. "But there's still the unknown. Are there long-term consequences of low-level exposure to these chemicals?"
Study reveals most water treatment technologies do not remove perfluorinated compounds
Of particular concern was the wide range of perfluorinated compounds identified in the water samples. These byproducts of various industrial processes, including the production of non-stick cookware and stain-resistant food packing and fabrics, was detected in most of the water samples, both treated and untreated.
"The perfluorinated compounds were at similar concentrations in the untreated and treated drinking water, suggesting that treatment techniques are largely unsuccessful," writes Brian Bienkowski for EHN. "Only one plant was successful at removing them, and it used activated carbon treatment."
This is all highly concerning, as a panel of scientists recently concluded that perfluorinated compounds, and PFOA in particular, are a probable cause of high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and pregnancy-induced hypertension, among other conditions. Many of these conditions have reached epidemic proportions throughout the U.S., potentially as the direct result of failed water treatment technologies.
Then there is the issue of chlorination and fluoridation, both of which can trigger reactions with other contaminants in the water supply and create new deadly compounds. According to Laurel Schaider, a research associate at the Harvard School of Public Health, these and other water treatment chemicals may exacerbate the toxic burden of tap water.
"Chlorination and other treatment technologies will remove some contaminants, but will react with others," she is quoted as saying to EHN. "Some compounds may appear to be removed but may be transformed [into] a chemical we know even less about."
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