Wastewater treatment plant tests show limited removal of organofluorines, potentially putting millions of people at risk

A research team led by Harvard University has found elevated levels of organofluorine in American municipal wastewater. More than 60% consisted of commonly prescribed fluorinated drugs, while six federally regulated perfluoroalkyl and polyfluoroalkyl substances (PFAS) made up less than 10% of the total extractable organofluorine in samples.

The work is published in the news Proceedings of the National Academy of Sciences.

PFAS are synthetic chemicals with thousands of variations that contain organofluorine structures with a tightly bonded chain of carbon and fluorine atoms. The strong bond gives the molecules nonstick properties commonly used for consumer products such as cookware, food packaging linings, waterproofing and stain-resistant carpets and clothing.

Because the carbon-fluorine bond is one of the strongest, these chemicals do not easily break down in the environment, earning the compound the title of “forever chemical.” Global contamination of soil and groundwater systems with PFAS is so extensive that PFAS has even been found high on the Tibetan Plateau, where it is carried by rain.

Currently, there are no safe and cost-effective strategies to reduce PFAS contamination once it enters the environment. Wastewater treatment plants serve most of the US population, yet less than 25% of measured organofluorine is removed, even under advanced processes.

In the study titled “High Organofluorine Concentrations in Municipal Wastewater Affect the Downstream Drinking Water Supply of Millions of Americans,” researchers sampled 8 large wastewater treatment plants with similar design capacities for organofluorine levels.

Researchers used bulk and targeted methods to detect extractable organofluorine, including PFAS, precursors and fluorinated drugs. A national wastewater dilution model was applied to simulate how discharges mix with drinking water intake under medium and low flow conditions.

Less than 10% of extractable organofluorine in wastewater comes from six regulated PFAS. Drugs were responsible for 62% to 75% of the measured organofluorine burden. The removal rate did not exceed 24% at any facility.

It was estimated that more than 20 million Americans relied on drinking water supplies susceptible to contamination levels above legal thresholds when wastewater-derived PFAS were considered – a major problem.

Although this is treated wastewater and not the water that comes from your home tap, it will mix with other water sources and “eventually” be diverted back to domestic use. That could ‘eventually’ happen sooner than most people think.

If you live near a river, your community probably uses the water from that river. That includes the towns and cities upstream and downstream of your community. They purify the river water for domestic use, use it, treat it as wastewater in a separate facility and then mix the treated wastewater back into the river. The process repeats itself again and again downstream, occasionally being diverted to agricultural, commercial or industrial applications.

By the time a coastal city uses water, it may have been purified, used and treated hundreds or thousands of times, or at least mixed with water that has already been used.

The Mississippi River has more than 4,500 publicly owned water treatment plants (POTWs). These POTWs treat the water and send it downstream in a water reuse system that flows through ten states along the river and a watershed that reaches another 21 states.

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