Guest Author: Susanne Brander
People in Wilmington, NC have stopped drinking water, from the tap that is, even though we have a water treatment facility, renovated just a few years ago, that boasts of the “latest and most innovative treatment technologies” on its website. Facebook has become dominated by parents exchanging opinions on reverse-osmosis filtration systems. What on earth is going on?
Well, towards the end of last year, a paper led by the Knappe lab at North Carolina State University, was published in Environmental Science and Technology Letters, one of the highest profile journals in the field. I became aware of the publication while sitting in the audience of a session at the annual American Chemical Society meeting in San Francisco in early April of 2017. A slideshow of the “Best Papers of 2016” was playing prior to talks beginning for the day, and I noticed that one of the studies was titled “Legacy and Emerging Perfluoroaklyl Substances are Important Drinking Water Contaminants in the Cape Fear River Watershed of North Carolina.” Well, I’d better look at that one I thought to myself, mentally adding it to my never-ending reading list, but at that moment didn’t give it a lot more thought because it wasn’t really big news that yet another chemical was being detected in the Cape Fear, or in any watershed for that matter. Although I did wonder where city “C” was in the graphic that briefly flashed on the screen.
What I didn’t know until I read the paper two months later—when I woke up to news breaking on social media that our drinking water might be contaminated and friends began asking me where to get clean water—was that this particular chemical, oddly named “GenX,” wasn’t just another pollutant making its way into the river via run-off or wastewater effluent. It was being directly discharged by a factory upstream of Wilmington, North Carolina (city C), where my family happens to live, and was detected in 2013 and 2014 at a concentration about two orders of magnitude higher (631 ng/L) than most other so-called micropollutants (e.g. pharmaceuticals, pesticides) typically are.
Chemours (a spin-off of DuPont), the company discharging GenX, makes a wide range of fluoroproducts, better known as TeflonTM. When we think of Teflon we usually think of non-stick cookware, but nowadays fluorochemicals are also added to clothing, paint, furniture, sports equipment, and beyond. C8 (Teflon), also known as PFOA (perfluorooctanoic acid), had been in use since the 1940s, and decades of peer-reviewed studies demonstrated that it was both a carcinogen and an endocrine disruptor. It concentrates in serum, the liver, and in the kidneys. C8 was also established to persist in the environment, showing up in sediments and fish tissues. Chemours stopped using C8 in 2009, prompting the switch to GenX, a supposedly less toxic but chemically similar compound. GenX was approved following one study that appears to have been funded entirely by Dupont.
This might sound surprising. Surely more studies would have been done, especially considering how toxic GenX’s predecessor C8 was deemed to be. Unfortunately, this is a prime example of how chemicals in consumer products are approved and regulated in the United States. The Toxic Substances Control Act, which was enacted in 1976, should give the EPA the authority to test chemicals before they come into use and to set standards, but continual reductions in the EPA’s budget and powerful lobbying efforts by the chemical industry have weakened TSCA considerably. As a result, toxicologists often feel that we are playing a perpetual game of whack-a-mole, conducting research on one chemical or class of chemicals while hundreds of other new compounds are introduced without adequate study.
While there is reason to be concerned about GenX, we currently know very little about it. What we do know is that it is similar in structure to C8. The biggest difference is that chemists have added an ether (oxygen atom) to the middle of a long chain of carbon-fluorine bonds (Figure 1), possibly making the chemical less persistent and potentially easier to metabolize. But one study in rodents, which actually demonstrated tumor formation at high concentrations doesn’t allow for a definitively safe level of this new chemical to be determined for humans drinking it daily, nor for the fish and invertebrates swimming around in it. In fact, this finding should prompt further study.
Furthermore, the Wilmington water treatment plant (and most plants nationally) cannot remove it. In fact, Knappe’s lab demonstrated that GenX concentrations increase slightly following treatment, potentially because other similar chemicals from the plant are oxidized into GenX in the plant. The best the inhabitants of Southeastern North Carolina can do is to follow the precautionary principle, that is in the absence of scientific information or consensus, that the best possible action is to avoid exposure until more data are collected.
A week following the news breaking there are more questions than answers, with the understandable focus and concern on potential human health impacts leaving too little thought behind for the aquatic ecosystems and their inhabitants that may also be impacted. In the meantime, we now schlep 5-gallon glass carboys filled with reverse-osmosis treated water home each week for drinking, brushing teeth, and making coffee and begin to think about designing experiments that will address the endless questions that scientists and residents have. Science (and the funding of it) moves slowly, and it will be years before we have any definitive answers. But if any good is to come out of this water scare, it will be further evidence that we need a better framework in place for testing chemicals before they show up in our homes.
Susanne Brander is an Assistant Professor at the University of North Carolina Wilmington.