April 18, 2022
By Middle Susquehanna Riverkeeper Association
Armed with 19 years of industry experience in pharmaceuticals, Lou Ann Tom, associate professor of chemistry at Susquehanna, uses her research to reduce the impacts of pharmaceuticals on our state’s waterways — including the use of photodegradation to detoxify medications before they get into the environment.
Prior to joining Susquehanna in 2007, Tom worked as a chemist/senior scientist at Merck & Co. Her research into photodegradation of pharmaceuticals has been supported by her students.
“I am sure there are other people doing this sort of work, but we are doing it here at Susquehanna with undergrad students doing the bulk of the work,” she said. “They are learning how to use the equipment and how to do the analyses, so it is beneficial for them. It is beneficial for me, and ultimately, I think it is beneficial for everybody.”
Using Photodegradation to Detoxify Medications
Tom’s research explores a potentially game-changing way to detoxify medication before it gets to our waterways via photodegradation.
“Too often when the public has extra medication and people aren’t sure how to properly get rid of it, some may be thrown in the trash or down the sewer, and then there is the potential that it gets into our environment,” Tom said. “We are looking at methods to degrade the pharmaceutical in an easy way so when they are disposed of in more traditional ways, the toxic component is gone.”
Tom is experimenting with the use of ultraviolet light to degrade drug toxicity.
“Ideally, at some point, there would be a place where the public could drop off unused pharmaceuticals and they can immediately be treated via UV light and maybe a catalyst to speed up the degradation,” she said. “Once the toxicity is gone, it could be disposed of and no longer a threat to the environment.”
So far, the research shows some very promising results, especially for medications that are water soluble, which means they dissolve in water on their own naturally.
“For water-soluble pharmaceuticals, degradation using just UV light is very quick,” she said. “Within a matter of a few hours, the component has either broken down or it is in levels that are much lower — usually at a point where we can no longer detect it using regular methods.”
Some of the most common water-soluble medications Tom has studied via her photodegradation work include lisinopril, albuterol, hydrochlorothiazide and atenolol.
“We did a survey looking at which are the most common pharmaceuticals that people have left over and may need to dispose of,” she said. “These water-soluble drugs degrade very quickly with UV light. You need to use specialized equipment to see these in very, very low levels, like parts per trillion, but we do know they degrade to less than parts-per-million levels in less than a day.”
Water-insoluble medications — such as warfarin (Coumadin or Jantoven), phenytoin (Dilantin), fenofibrate (Tricor or Triglide), carbamazepine (Tegretol) and sulfamethoxazole (Bactrim) — pose a different issue.
“Some of the most common water-insoluble drugs take much longer to degrade under UV light — like over a week and some of them two weeks without really degrading in toxicity,” said Tom. “With these pharmaceuticals, we are experimenting with catalysts that, when used with the UV light, can speed up that process.”
One of those potential catalysts may be found in an unlikely source.
“I am working with a colleague at St. Francis University who is doing work with acid mine drainage and there is a theory that some of the acid mine drainage residuals, like iron oxide, could potentially speed up the degradation when used with UV treatment,” Tom said. “Obviously this would be important in not only in speeding up that process, but also providing a beneficial usage of mine drainage residual.”
Determining Pharmaceutical Impacts
Among the variety of medications created at Merck while Tom was there was Ivermectin, a drug used to treat come parasitic diseases.
“Ivermectin is fairly toxic and treating it was a high priority, so I got involved in studying low levels of pharmaceuticals that may wind up in the river,” she said. “Some of the components were very difficult to analyze because some things can be toxic at levels that could be very, very low – almost too low to measure.
“Ivermectin can be an issue at parts per trillion. Most of the common analytical techniques have an ability to test to parts per million or parts per billion. I started studying ways in which we could develop a method to see that compound at parts per trillion. From there, I started looking at other compounds that were common and potentially could be toxic in really low levels.”
That led Tom to work with molecularly imprinted polymers, which are designed to detect a very specific compound at low levels.
“If you have a sample of river water with other things in it, the polymers are designed to detect and concentrate a very specific compound, and then you can use regular techniques to analyze it,” Tom said.
Lack of Recent Statistics
Despite indicators that pharmaceuticals are increasingly impacting the aquatic ecosystem, there have not been recent studies into actual levels of them in our watershed, according to several main sources.
“We have not sampled for pharmaceuticals in the past few years,” said Andrew Reif of the U.S. Geological Survey (USGS). “Our last major effort was in 2006-2009.”
Results from that study found a total of 51 different contaminants of emerging concern in streamwater samples collected from 2007 through 2009 at 13 sites located downstream from a wastewater-effluent-discharge site within the greater watershed. Among the most commonly detected compounds were carbamazepine and sulfamethoxazole – two of the water-insoluble drugs that Tom and her team are targeting in their photodegradation work.
Mindful Medication Disposal
“We know that there are traces of pharmaceuticals and insecticides being found in the waterways. They can do potential damage to the life within the river, as well as life that is around the river. The studies of how high those levels need to be in order to be damaging are ongoing,” Tom said. “However, the fact that we are finding levels of pharmaceuticals in waterways has to be concerning to anybody who uses those waters for recreation. And ultimately, our drinking water comes from those sources, too.”
This is why people need to be mindful of how they dispose of unused medication, Tom added.
“Disposing of any sort of pharmaceutical in any way where it can get back to the environment – either by flushing them down a toilet or throwing them in the trash – should concern anyone who is the least bit environmentally conscious,” she said.
Tom encouraged the use of medication takeback programs that offer boxes or days for people to dispose of unused medications. According to Geisinger, medications the health system collects in this way “are securely transported to an incinerator for final disposal.”
Geisinger has been an important partner for Tom and her team in finding alternate ways to safely dispose of medications without negatively impacting the environment.
“In our work, we start with a pure compound, and then we switch over and try to compare that with the actual pills or capsules that the public has because that’s the form they’re going to be disposed in,” she said. “Geisinger has provided a lot of the actual pill form of the drugs for us to continue using in the studies.”