Cloelle Danforth, Scientist.
This post originally appeared on the EDF Energy Exchange blog.
Over the past few years, we’ve written a lot about the wastewater generated from oil and gas production — specifically, how little is known about what’s in it and the potential risks of exposure.
But as states try to set standards for how to safely treat and dispose of this waste, there are two chemicals in particular that deserve to be among the regulatory priorities.
The first is a class of synthetic chemicals known as per- and polyfluoroalkyl substances — PFAS for short. Members of this class, often referred to as “forever chemicals” because they are highly persistent in the environment, are known to cause adverse health impacts in humans. This can include a range of symptoms, including damage to the immune system, low infant birth weights and cancer.
The second chemical is 1,4-dioxane. Short-term exposure to this carcinogen can cause immediate health impacts, like eye, nose and throat irritation and impaired lung function. Prolonged exposure can lead to liver and kidney damage, as well as cancer.
The oil industry’s wastewater contains thousands of different chemicals in varying combinations, depending on what chemicals were used in the fracking process and where the water came from, so we can’t be sure that every sample of produced water contains these chemicals. However, their potency and their pervasiveness should raise a flag for any policymaker charged with protecting public health and the environment.
For example, researchers have detected PFAS and 1,4-dioxane in samples of produced water across the country, including Colorado, Pennsylvania and Texas. The chemical tracking database FracFocus also notes that that 1,4-dioxane has been used nearly 700 times to frack wells in Texas and New Mexico in recent years.
Both chemicals are hazardous, persist for long periods in the environment and are hard to detect, especially in produced water, which is incredibly salty. Many of the methods used to detect chemicals simply don’t work in this complex wastewater. So, while we know these chemicals have been found in produced water, we don’t always know how much or how often. This makes designing safe and effective treatment strategies difficult.
This is a problem as many states (particularly arid states) have started exploring the possibility of treating the oil and gas industry’s wastewater and using it for things like aquifer recharge or crop irrigation. These two chemicals are resistant to treatment, with examples of PFAS ending up in biosolids and 1,4-dioxane in drinking water sources due to inadequate removal from wastewater.
This is new territory for the agencies charged with protecting our health and our water. Traditionally, the vast majority of the oil industry’s wastewater has been stored deep underground in disposal wells. Allowing it to be treated and repurposed could mean introducing these chemicals into more places — creating unnecessary risk for the people exposed to them.
Until our detection methods and discharge standards improve, we can’t say with certainty that reusing oilfield wastewater outside the oilfield can be done safely.