Lead isn’t the only harmful substance that can make its way into drinking water.
Chemicals from pharmaceuticals, pesticides and personal care products can all end up in the water supply.
90.5 WESA’s Liz Reid spoke with Carnegie Mellon University chemistry Ph. D. student Genoa Warner about her work developing new compounds that can remove those micropollutants from the water.
Their conversation has been edited for length and clarity.
LIZ REID: What are micropollutants?
GENOA WARNER: Micropollutants are any pollutants present in the environment at very small concentrations that can still cause harm.
REID: So, that doesn't refer to the size of the pollutant individually, it refers to the concentration?
WARNER: Yes. So, it's something that you might think, you know, the dose makes the poison -- just a little bit won't hurt you. But these are the kind of pollutants that will hurt you with just a very small amount out there.
REID: Can you give us some examples?
WARNER: Pharmaceuticals are a really major example that occur in water. So, in your drinking water, you'll find Prozac and Zoloft, you'll find beta-blockers (medications used to treat high blood pressure or heart arrhythmias) you'll find any common pharmaceutical, estrogens as well, like the active ingredient in birth control pills. We're also talking about chemicals that are in your personal care products.We're talking about things like BPA. And, of course, pesticides and agricultural chemicals.
REID: So, how do things like pharmaceuticals get into the water supply? I can see how like stuff in your shampoo gets in, how do pharmaceuticals get in the water supply?
WARNER: Well, they can get in when people flush them when they don't use them. But actually, many pharmaceuticals are excreted from the body when we're done with them.
REID: And then things like fertilizer and pesticides -- those just sort of get into the water supply via runoff?
WARNER: Yeah. The majority of them are washed off.
REID: So, why are these micropollutants a problem in the water supply?
WARNER: Many of them are endocrine-disrupting chemicals, which are compounds that can interfere with the workings of the endocrine system in the body. And that's a big problem because hormones in the body are active at very low concentrations.
REID: I know you're a chemist, but a little biology lesson here: what is the endocrine system? What does it do and why is it bad if it's disrupted?
WARNER: The endocrine system takes care of many different jobs in your body. Of course, the hormones of the endocrine system, the main ones that you will know of are estrogens, testosterone, progesterone. And the endocrine system is in charge of development. So it's particularly a big deal for developing fetuses and for reproduction for undergoing puberty. And then the system is also important for general homeostasis and metabolism, brain function. It's important in almost every system in your body.
REID: So, these chemicals can actually disrupt these processes then?
WARNER: Yes, exactly. And a lot of them disrupts these processes because structurally the chemical looks like a hormone.
REID: And one of the really sort of interesting developments in the past say decade or so is there were these bass that were discovered in rivers here in Pennsylvania, and also in other states, that actually were becoming intersex. Is that right?
WARNER: Yeah. This is happening to fish all around the world. In fact, some male fish are growing eggs and developing female characteristics and this is due to endocrine-disrupting compounds in the water, specifically the estrogens that I mentioned before.
REID: That sounds kind of crazy. Are these fish sort of like the canary in the coal mine?
WARNER: Yes, exactly. They really are. And so the fish are very sensitive. A lot of our ecosystems are very sensitive to endocrine-disrupting compounds in a way that adult humans aren't necessarily. So, for one of us to consume some amount of an endocrine-disrupting compound might not have a huge effect on us. You know, we aren't becoming intersex from these compounds. They have the biggest effect during development and so they can have serious effects for fetuses and during puberty and growth -- children in general.
REID: Why are these micropollutants so hard to remove from the water supply?
WARNER: Our wastewater system just isn't designed to remove them right now. And in America, there isn't any legislative incentive to do so. In Europe, they actually are instituting a number of systems of add-on water treatment purification processes to remove these from water. But a lot of these chemicals were designed to be persistent, they're designed to stick around. You know, you put a pesticide on your crop and you don't want it to break down or wash away right away.
REID: But you developed a process to remove them from the water supply. Describe this process.
WARNER: Yes, so, we make an oxidation catalyst that can degrade a number of these pollutants in water. So, our catalysts are inspired by natural enzymes. And they work in a similar way to break down pollutants. And so we add our catalyst and we add hydrogen peroxide in the water, which activates the catalyst and that will actually blow up the pollutants, actually destroy them and break them down.
REID: How long were you working on that project?
WARNER: Our catalysts, they're called TAMLs. They've been in development for over 20 years and our lab here. And for the past five years, I've been working on making a new class of TAMLs that we call new TAMLs, because we've changed the structure significantly to make them more resistant to breaking themselves down. We want them we want them to last a little bit longer in water, so that they can be commercially viable. They can be economic to use to destroy micropollutants, but at the same time, we don't want them to last forever. They don't last forever. When you put them in water, though, they'll work for a couple of hours before they break down themselves into harmless pieces.
REID: So, those water systems in Europe, you said that some of them are actually addressing this problem. Are they using TAMLs?
WARNER: No. In most of Europe they're using ozone or activated carbon or other advanced oxidation.
REID: Which is the same stuff that's in your BRITA, right?
WARNER: Yeah. Carbon, granulated carbon is what's in your BRITA. And that is a very good solution, but it's very expensive. And so these are solutions that have been implemented in Germany and Switzerland, in the Netherlands, but they're not accessible to the majority of the world simply because they're very expensive.
REID: And, as we know here in Pittsburgh, and across the country, a lot of our water systems don't have a lot of money to work with. Of every $2 that comes in, PWSA spends $1 to pay its debt. So, water systems here in the U.S. really need economical solutions if they're going to tackle this problem.
WARNER: Yes, absolutely.