Missoula’s groundwater tests positive for drugs
Downing antidepressants, painkillers and antibiotics may not be strictly voluntary anymore. Missoula’s groundwater contains traces of commonly ingested pharmaceuticals, as do samples from local septic tanks and the wastewater treatment plant, according to recently published research.
The first study to examine Missoula’s water for the presence of pharmaceutical compounds was conducted by geologist Emily Godfrey, University of Montana geology professor William Woessner and Mark Benotti, and was published in Ground Water Journal’s latest issue. It examines the link between drugs that pass unmetabolized through humans and Missoula’s septic tanks and groundwater. It’s the follow-up to Godfrey’s and Woessner’s 2004 study that discovered pharmaceuticals in waste streams of both the Missoula wastewater treatment plant and local septic tanks.
While the findings raise an assortment of questions and speak to the need for more research, both scientists and local officials say it’s too early for Missoulians to draw conclusions about their significance.
“People shouldn’t be in an uproar,” says lead author Godfrey, who conducted the research as part of her master’s thesis at UM. “The levels are still very low concentrations and they have not yet found any kind of impact on humans.”
However, even at low levels, the mere presence of drugs in groundwater is a concern since the impact on humans, animals, plants and microorganisms is unkown. And it’s a concern Missoula isn’t alone in addressing.
For instance, the Montana Department of Environmental Quality recently conducted a study of chemicals in Helena’s groundwater and discovered 22 different pharmaceutical and personal care products in private and public drinking water. Over the last 20 years, Woessner says, scientists nationwide have developed highly specialized testing to find nontraditional water contaminants, including hormones that change the sex of fish and pharmaceuticals, which have been found frequently.
“This is something that may have been in the system for a long time, but only recently are we beginning to be able to detect it,” Woessner says.
The Missoula study explored the presence of 22 common pharmaceutical compounds in the Frenchtown High School septic tank and seven local monitoring wells that tap into groundwater below. Twelve of those 22 compounds were found in the septic tank, including acetaminophen, caffeine, codeine, carbamazepine (anticonvulsant and antidepressant), cotinine (nicotine byproduct), erythromycin-18 (antibiotic), nicotine, paraxanthine (caffeine byproduct), ranitidine (histamine), sulfamethoxazole (antibiotic), trimethoprim (antibiotic) and warfarin (anticoagulant). Four of those—carbamazepine, trimethoprim, caffeine and warfarin—were also found in the groundwater. The research builds on the 2004 study that found 18 of 22 compounds in 42 local septic tanks; 12 compounds in wastewater entering Missoula’s wastewater treatment plant; and nine compounds in the effluent discharged from the wastewater plant into the Clark Fork River.
Starr Sullivan, wastewater division superintendent, says the city doesn’t monitor for pharmaceutical compounds and wastewater plants aren’t designed to break them down, though he suspects it will become a growing concern in the future. And while Mountain Water Company General Manager Arvid Hiller says most local drinking water is pumped from wells that reach deeper into the aquifer than do the study’s monitoring wells, he says the study’s findings merit further research.
The levels of drugs found in Missoula’s groundwater are very low, much less than an adult dose prescribed by a doctor. For comparison’s sake, Godfrey offers the example of caffeine. She says a can of Coke contains 50 milligrams of caffeine, and their highest caffeine reading in groundwater was 206 nanograms per liter.
“If you wanted to get as much caffeine [as the equivalent of a Coke] in your body from drinking the water, you’d have to drink 1.1 million cups of water,” Godfrey says. “That’s a lot of water. That’s how low these concentrations are.”
Woessner says the fact that pharmaceutical levels are far below a therapeutic dose is relatively good news, but a number of other questions remain: What is the impact of consistent low doses over the long-term? Are there impacts on fetuses or children? What about microorganisms, fish, plants and other mammals? Does it promote resistance to antibiotics? Additionally, there’s the fact that the local study only evaluated 22 pharmaceutical compounds, although hundreds of others exist and may be filtering down into our water supply.
“The bottom line is we really don’t know what the impacts of these concentrations are,” he says.
Peter Nielsen, environmental health supervisor for the Missoula City-County Health Department, says that while future research is needed, the recent study alone is worth Missoulians’ attention.
“It’s probably news to most people that they would find an antidepressant in their drinking water,” he says. “Certainly levels we’re seeing in the groundwater are low, but it shows you’re drinking water that’s got some sewage in it, although it’s quite diluted.”
Although some medications are vitally important for certain people and can’t be decreased, Nielsen says cutting back on unneeded drugs is something many Missoulians can do in response to the recent study. Besides addressing the intake of drugs that survive human metabolism, Nielson says drug disposal is also an issue.
“The standard advice used to be to flush them down the toilet, but now that we’re seeing them in the water we’re not recommending that,” he says.
Instead, he says it’s better to place pills that need to be destroyed into a bottle with no label, mix in water to render the pills unusable and place it securely in the garbage.
Even then, says Woessner, people should realize their meds will end up in the landfill, but that’s better than trickling into the water supply.
“We’re waiting for some risk assessments and exposure issues to be resolved,” he says. “But whether there are risks or not, it seems like it would make sense to limit unnecessary releases into the system.”