Water is rarely pure. Whether it is water that enters our home for drinking and bathing, or dirty water flushed down the drain and returned back to the environment, there are hundreds of potential contaminants that remain in our water, even after purification efforts.
With nearly half of the population in the United States using at least one prescription drug in the past 30 days, and more than 20 percent using three or more, remnants of those drugs are commonly found in the water both exiting and entering our homes. And, while water treatment plants must meet federal regulations, most standards haven't been updated in 40 years. The result is a system that isn't able to routinely detect or completely remove pharmaceuticals and hundreds of other chemical compounds from drinking and wastewater.
Whether over-the-counter drugs or prescription medications, a portion of the medicines we ingest aren't used by our bodies and are excreted into our wastewater. Likewise, unused pharmaceuticals are often flushed down the toilet in whole form in order to keep out of the hands of others. While sewage systems are designed to remove harmful contaminants from our wastewater before being released back into the environment, studies have found anywhere from 20 percent to 90 percent of pharmaceuticals are typically removed from "influent," or sewage, depending on the treatment process used. The remaining chemicals are discharged as "effluent" and pumped back into local waterbodies.
Contamination from those wastewater treatment plants and leaking sewage and septic systems eventually ends up in larger rivers and lakes that are used as sources for drinking water. Treatment systems used for drinking water typically remove anywhere from 50 to 99 percent of pharmaceuticals from the water before reaching local homes. For instance, chlorine-based drinking water treatment plants — the most common in the United States — remove about 50 percent of pharmaceuticals. More advanced systems can remove more chemicals, with reverse-osmosis filters able to remove 99 percent of contaminants.
"Treatment doesn't remove all pharmaceuticals, and they aren't designed for that," said Laura Verona, who oversees the Michigan Department of Environmental Quality's (MDEQ) wastewater division in southeast Michigan. "They have looked for pharmaceuticals in water and have found them, but in low concentrations, it's nothing that should be cause for alarm."
The study of pharmaceuticals and other trace chemicals in water stemmed from research done in the late 1990s by the United States Geological Survey. By 2000, scientists had tested 139 streams in 30 different states for the presence of human and veterinary pharmaceuticals (including antibiotics), natural and synthetic hormones, detergent metabolites, plasticizers, insecticides and fire retardants. The results showed about 80 percent of streams tested had the presence of at least one of the contaminants, with half of the streams containing at least seven or more of the chemicals. The study, which was the first of its kind, led to a new classification of contaminants, considered "contaminants of emerging concern," and questions about how they impact waterways and sources for drinking water for millions of people.
In terms of research, the overall focus has been on aquatic organisms, which receive more exposure to wastewater on a constant basis, said Ed Furlong, an environmental chemist at the United States Geological Survey's National Water Quality Laboratory, in Lakewood, Colorado.
"Most aquatic organisms are exposed continuously," he said. "Many tend to focus near wastewater discharge because it is warm and has an ecosystem. Those fish are probably more likely to reflect exposure, and that's where the majority of research is now."
In terms of potential risks to humans, the main concern regarding pharmaceuticals in water has focused on antibiotic chemicals, which may lead to more resistant bacteria strains. Endocrine disrupting chemicals, such as hormones, have been shown in several studies to alter the reproduction systems of some aquatic organisms.
Studies have indicated the amount of pharmaceuticals in drinking water and its sources are minuscule, typically measured in micrograms (a millionth of a gram) or nanograms (a billionth of a gram) per liter of water. However, the long-term impact to humans from the constant exposure to a virtual cocktail of pharmaceuticals is largely unknown.
"We can never not worry about it. From a scientific perspective, it's an issue to find it in water, but in some cases, we think there is more of an ecological risk than a human health risk," said Joan B. Rose, the Homer Nowlin Chair in Water Research at Michigan State University and an international water expert. "The levels we find in water are thousands below our therapeutic uses. But, if it's in water, even at these lower levels, what does that mean? Does it make it all the way to drinking water, and are we being exposed to these on a consistent basis? Do we have good methods to find it, and if we can find it, how widespread is it? Once those questions are answered — and they are starting now — we can identify the hotspots. But the health effects side has been very difficult to get research done. I think we need longterm studies to know, and maybe those haven't been done yet."
Pharmaceuticals are just one of the many "contaminants of emerging concern," which are being found in low levels across the country which are having an impact on surface water and aquatic life. "Emerging" contaminants, which include pharmaceuticals, personal care products, and endocrine disrupters, have been detected in municipal wastewater, surface and ground waters, drinking water and aquatic life around the globe.
A study into chemicals of emerging concern in the Great Lakes region, conducted by scientists from the United States and Canada with the International Joint Commission (IJC), found six chemicals with a high frequency of detection and low removal rate from sewage or wastewater. Those chemicals include one herbicide and five pharmaceuticals, including an anti-seizure drug, two antibiotics, an antibacterial drug and an anti-inflammatory. The study also found high frequencies of caffeine, acetaminophen and an estrogen in sewage, but with higher removal rates.
The Great Lakes Restoration Initiative, a federally-funded effort focusing mostly on stopping invasive species, improving wetlands and removing outdated dams, also supports research to study chemicals of emerging concern.
Joe Duris, a microbiologist at the United States Geological Survey's (USGS) Michigan/Ohio Water Science Center, in Lansing, said the initiative has allowed the USGS to study the effects of statins, birth control, anti-seizure drugs, antibiotics, painkillers and other drugs on water and aquatic life.
"We are also trying to understand the relationship between some of the pharmaceuticals and the relation of antibiotic resistance in the environment," Duris said. "We have done some studies and have evaluated some locations in Michigan."
The presence of antibiotic-resistant bacteria in Oakland County was first discovered more than a decade ago, according to a study by the USGS and the Oakland County Health Department. The study, which took water samples from 20 different streams, also found E. coli levels that exceeded the state's recreational water quality standards of 300 E. coli per 100 milliliters of water in 19 of 35 of the samples taken. Among the locations sampled were the Rouge River in Birmingham and Paint Creek in Rochester.
Scientists conducting the study said high fecal bacteria concentrations are an indicator of possible fecal pollution which may carry harmful pathogens and pose a threat to human health.
The study found both antibiotics and strains of E. coli resistant to antibiotics at almost all sites tested, with the highest percentage of resistant bacteria in the Clinton River at Auburn Hills. Antibiotics used to treat humans were discovered in the water at the same location, while antibiotics used to treat animals were discovered in the Paint Creek in Rochester. Additionally, in some locations in the county there was the presence of E. coli that was resistant to the antibacterial treatment of the the antibiotics cefoxitin and ceftriaxone.
Duris said it's important to note that the presence of antibiotics in water doesn't necessarily mean antibiotic-resistant bacteria is also present.
"If you find an antibiotics in the water, you don't necessarily find the resistant bacteria," he said. "Bacteria and antibiotics move through the water very differently, and bacteria can do things that a chemical in the environment can't. It's a complicated dance in the environment to find the relationship as it relates to bacteria."
It should also be noted that the monitoring station in the Clinton River at Auburn Hills was the only one in the test that was located downstream from a wastewater (sewage) treatment discharge, that being the treatment facility in the city of Pontiac, which discharges in the river.
Overall, E. coli resistant bacteria were more common at urbanized sites.
"This pattern indicates the source of this resistance may be a result of human or urban impacts, such as wastewater from wastewater treatment plants or failed septic systems, urban runoff, industrial discharges, urban animal populations (domestic animals and birds), and so forth," the study concluded.
A more recent study into organic contaminants in Great Lakes tributaries completed by the United States Geological Survey in March found over 90 percent of samples from the Clinton and Rouge rivers exceeded water quality benchmarks for at least one or more contaminants by a factor of 10 or more. The Clinton River had nine chemicals that exceeded water quality benchmarks (the most of any water tested), followed by the Rouge River, which had eight.
Overall, the study found one or more chemical compounds in 92.5 percent of 709 water samples taken. Mixtures of 10 or more compounds were discovered in 34 percent of samples at 25 percent of the sites, with the Clinton River at Auburn Hills testing positive for 53 compounds in a single sample. The chemicals most frequently found were the insect repellent DEET and carbozole, a chemical used in the production of pigments. Other chemicals found include those found in fossil fuels, herbicides, and flavorings and fragrances.
While the study didn't look specifically at pharmaceutical contaminants, it highlighted the complexity of compound mixtures in streams, particularly those with urban influences.
The Clinton and Rouge rivers also were included in a study of antibiotic, pharmaceutical and wastewater-compound data for Michigan from 1998 to 2005, conducted by the United States Geological Survey. Those findings again reflected the findings of earlier studies.
That study found the maximum number of chemicals detected at any site was 20 (Clinton River at Auburn Hills), followed by 18 (the Evans Ditch at Southfield), and 17 (the Clinton River at Yates). Pharmaceuticals detected included albuterol (an asthma medication); dehydronifedipine and warafin (medications used to treat high blood pressure); and sulfamethoxazole (an antibiotic).
Duris said testing for pharmaceuticals in the Great Lakes and its tributaries continues to be an "active area of interest." Currently, he said, the USGS is looking at wider samples at the mouths of tributaries, which will offer a representation of an entire watershed, rather than localized spots.
Duris said levels of pharmaceuticals in larger water bodies, such as the Great Lakes themselves, are far lower than tributaries, as contaminants often bind to solids and settle to the bottom or are greatly diluted by the entirety of the lake.
Cheryl Murphy, an ecotoxicologist of fish at Michigan State University, said the impact of pharmaceutical birth control on fish are particularly concerning, as they have been shown to feminize male species and lead to intersex fish.
"They are finding intersexed fish in a lot of different areas — in the Great Lakes, near Minneapolis, the Chesapeake Bay and other areas," she said. "They do have effects, but we are just starting to understand them.
"These are drugs and pharmaceuticals that we take for all sorts of different reasons, and they get flushed out in wastewater treatment effluent because we aren't extracting them. It gets in the waterways, and because a lot of vertebrates have a lot of the same receptors as humans, they react on fish, frogs and other organisms."
Murphy said trace pharmaceutical effects on humans may differ because the drugs don't tend to accumulate in the same way in people. That means eating fish exposed to pharmaceuticals likely won't cause adverse effects when consumed. Still, Murphy said studies have shown instances where estrogen levels in water have caused dramatic changes to fish populations.
In one Canadian study, the effects of birth control on fish was studied at an experimental lake area in northwestern Ontario, which showed that constant exposure to estrogen lead fathead minnows to feminize male fish, and lead to a near extinction of the species over a seven-year period.
"It is shown that birth control can cause a whole (fish) population to collapse," Murphy said. "There has to be more work done to prevent all of these things from wastewater."
United States Geological Survey's Furlong said while wastewater treatment plants often receive the blame for pharmaceutical contamination of our rivers, lakes and streams, most facilities are simply operating under federal regulations.
"It's easy to point to wastewater as the culprit, but what we put in it, they try to take out," he said. "They haven't had the kind of focus that regulation brings. It's a skilled and dedicated group of professionals."
Richard Rediske, the senior program manager of the Robert B. Annis Water Resources Institute at Grand Valley State University, said small concentrations of pharmaceuticals in water don't necessarily mean a problem will be present. However, the potential is typically greater at locations where wastewater discharged into a stream or river makes up a high percentage of streamflow.
"The problem with pharmaceuticals is that they are excreted by our bodies and go through the wastewater system, and they are never taken out by common treatments," he said. "Nicotine and caffeine are common, then others like NSAIDs (anti-inflammatories), acetaminophen, high blood-pressure medications and anti-depressants, but all in very small amounts. It takes a lot of wastewater to raise the level up high enough that it might be of concern.
"I don't think it's an issue in Michigan as far as causing problems with fish, but we need more work and monitoring, and more low-dose studies."
In southeast Michigan, Rediske said wastewater discharges from Ann Arbor into the Huron River were shown to increase estrogen in Ypsilanti's drinking water.
"That's an instance where a wastewater discharge is near a (drinking) water intake," he said. "Use of birth control and other pharmaceuticals from Ann Arbor shows up in water, but not enough to cause a problem."
Oakland County residents connected to sewer systems have their wastewater treated by either the Great Lakes Water Authority (GLWA), formerly known as the Detroit Water and Sewerage Department (DWSD), or at one of eight municipal wastewater treatment plants in Commerce Township, Holly, Lyon Township, Milford, Pontiac, South Lyon, Walled Lake-Novi, and Wixom. Residents not on a sewer system operate independent septic systems.
All eight of the Oakland County wastewater treatment plants and the GLWA's plant use an activated sludge process to treat sewage. Wastewater plants in Walled Lake-Novi, Commerce and Pontiac are overseen by the Oakland County Water Resources Commissioner's Office, while other municipal systems are overseen by those municipalities.
Oakland County Water Resources Commissioner Jim Nash said while pharmaceuticals in wastewater are an important issue for everyone, he isn't aware of any technical data on the subject at any of the treatment plants overseen by his department.
The GLWA operates the largest treatment facility in North America, serving about 40 percent of the state's population and treating between 600 million and 700 million gallons of wastewater on an average dry day. Because some communities operate combined sewage and stormwater drains, that figure can spike during rainfall events.
"The primary process we use for treatment is biological, and activated sludge," said Suzanne Coffey, COO of wastewater for the GLWA. "It's a multi-stage process, where the naturally occurring bacteria and microbes treat and metabolize contaminants."
The primary stage first screens the water and allows solids to settle out before filtering it through sands. The secondary stage uses the activated sludge process. After all processes take place, the water goes through a chlorination process and is then discharged to the Detroit River and Rouge River. During wet weather, there are also untreated combined sewer overflow discharges to the same two rivers, and treated combined discharges to the Detroit River, Conner Creek, the Rouge River and the O'Brien Drain.
Wastewater treatment plants in Oakland County also discharge treated water into local waterbodies, including the Rouge River in Commerce Township; the Shiawassee River in Holly; two groundwater discharge beds in Lyon Township; the Clinton River in Auburn Hills for Pontiac; the Huron River in South Lyon, Milford, Walled Lake-Novi, and Wixom.
Coffey said the activated sludge process does treat for some pharmaceuticals, but there is still "a huge variety of potential contaminants." She said the department is currently working on a wastewater master plan, which will look at different technologies for the future, but implementing the plan could take up to 40 years.
Contamination of surface waters from wastewater treatment plant discharges was also tested by the International Joint Commission (IJC), which found several antidepressants in both incoming wastewater and treated water discharged into the Grand River, which spans from south of Jackson to Lake Michigan. Concentrations were found more than 100 yards downstream from the area of discharge.
In addition to discharges of treated wastewater, the sludge used in the sewage treatment process, which is often applied to farmland as a type of fertilizer, was also found to be a source of aquatic contamination, with runoff into surface water. In some cases, pharmaceuticals absorbed by the sludge were found to be at higher concentrations than other effluents, according to the study. Testing at wastewater treatment plants in six different cities in Michigan found 14 different pharmaceuticals, including several antibiotics, acetaminophen, caffeine and carbamazepine, which is used to treat epilepsy.
Surface waters at a Lake Huron drinking water plant, where portions of Oakland County residents, including portions of the Birmingham/Bloomfield and Rochester/Rochester Hills areas receive their drinking water, were also found to have trace amounts of "a vast number of pharmaceuticals," according to the study.
In Oakland County, the majority of residents receive drinking water from the Great Lakes Water Authority (GLWA), formerly the Detroit Water and Sewerage Department, while others not hooked into regional system are served by local wells. For Oakland County residents hooked directly into the GLWA's system, water comes from two main sources. Those residents living north of 14 Mile Road receive their water pulled from the utility's Lake Huron Water Treatment Plant, near Port Huron, while those living south of 14 Mile receive water from the GLWA's Springwells treatment plant, along the Detroit River, with water pulled near the head of Belle Isle and from the Canadian side of the river.
The existence of pharmaceutical compounds in many drinking water sources led the scientists with the International Joint Commission to conduct research on the effectiveness of drinking water treatment plants on the removal of the compounds. Pharmaceuticals were found in more than 50 percent of pretreated drinking water.
"In order to evaluate the removal extents of pharmaceuticals precisely, the authors analyzed the pharmaceuticals in 22 paired raw and treated water samples," the study stated. "The water treatment plants in Detroit and Windsor generally failed in the complete removal of pharmaceutical substances ibuprofen, gemfibrozil (a lipid/cholesterol regulator), ketoprofen (an anti-inflammatory), naproxen (an anti-inflammatory), lasaloid (an antibacterial agent in animal feed), erythromycin (an antibiotic), tylosin (an animal feed additive), and ciprofloxacin (an antibiotic)."
While the International Joint Commission found the Great Lakes Water Authority's Water Works Park water treatment facility, on Jefferson Avenue in Detroit, didn't remove all pharmaceuticals, the facility does utilize one of the more state-of-the-art ozonation treatment processes, thanks to a $250 million upgrade at the facility, which was completed in 2002. According to the World Health Organization (WHO), conventional chlorination treatment of drinking water removes about 50 percent of pharmaceuticals, while ozonation, advanced oxidation, activated carbon, and nano-filtration can achieve much higher removal rates. The most effective process, reverse osmosis, can remove more than 99 percent of large pharmaceutical molecules. However, the organization states the cost of reverse osmosis systems aren't worth the benefit.
In ozonation, the treatment process doesn't add chemicals to the water, but rather uses ozone to eliminate contaminants. The process also creates a cleaner tasting and smelling water, and is believed to remove higher concentrations of pharmaceuticals. The process of reverse osmosis, which is most effective at removing salts and other contaminants, is accomplished by pushing water through a semipermeable membrane. While the process can remove up to 99 percent of contaminants, the cost is for such treatment is considerably higher.
"Implementing additional specialized and costly drinking water treatment, specifically with the intention of reducing trace concentrations of pharmaceuticals, is not considered necessary at this time, as the human health benefit would be limited," the organization said in its most recent study. "The most appropriate approach to minimize the presence of pharmaceuticals in drinking water and reduce human exposure is to prevent or reduce their entry into the water environment as far as reasonably practical. This can be achieved through a combination of preventative measures, including enhanced communication with the public on rational drug use and disposal of pharmaceuticals, education for prescribers, and systematic drug take-back programs."
Great Lakes Water Authority's Porter said the Water Works facility was upgraded in anticipation of new drinking water requirements.
"Chlorine isn't the primary disinfectant; we use ozone there," she said. "We were looking at changes and anticipated there would be a new requirement in the state. That didn't happen, but it was to our benefit. Ozonation is predominantly used in Europe, but we are taking hold of that."
Porter said additional upgrades are expected at the GLWA two other water treatment plants in the future, but the exact technology has yet to be determined.
"We are a pretty old system and due for some capital investment," she said. "We are looking at what is best for the area."
Porter said the Lake Huron water treatment plant currently has a conventional chlorination system, but it could be upgraded to a more state-of-the-art system, such as nano-filtration, which she said may be considered when the source water has low dirt.
"We are looking at the best choice that is most cost effective," she said. "This organization is committed to not just meeting regulations. We want to move beyond that."
The chlorination process, which is the most widely used process in the country, draws water from the bottom of a waterbody, such as Lake Huron or the Detroit River, and screens it for debris. After screening, it goes through a chlorination process where the water is cleansed and other chemicals, such as fluoride, are added to the water. From there, the water is moved to settling basins to allow additional contaminants to settle out of the water. The water is subsequently filtered again before going through a post-chlorination process and ultimately made available to customers.
While the federal Environmental Protection Agency (EPA) doesn't regulate pharmaceuticals and other "contaminants of emerging concern" in drinking and sewage treatment systems, the agency is working to learn more about the impact of pharmaceuticals on the environment and sensitive human populations, such as pregnant women, children and people with impaired metabolisms.
Mitch Kostich, a research biologist with the EPA's National Exposure Laboratory in Cincinnati, Ohio, is part of a team of scientists working on a model for estimating concentrations of the some 1,800 different medications approved for use in the United States that may be found in wastewater. The model will provide estimates for potential exposure rates and provide scientists with information needed to estimate overall risk and prioritize future research on those pharmaceuticals of greatest concern.
"Our work and our review of the work of other researchers suggests risks from pharmaceuticals in water, including drinking water, are very low," Kostich said. "For aquatic life, the results are not as clear, in large part because of the large number of very diverse species that might be exposed and therefore must be considered."
Clearly, more work needs to be done.