I can address that a little bit, but maybe Dr. Sauvé could add to it.
Yes, that's what we call “BTEX”, right? We're talking about the relatively small organic hydrocarbons. Those often are associated with petroleum oil, let's say, as well as other sources.
Those are not necessarily long-lasting, so if there's any good thing, those typically do not last in the environment for very long, but when you have them in groundwater, they still could persist for a relatively long time. Those are relatively easy to monitor, and it's often relatively easy to identify their sources.