Medicines have been detected in streams, landfill leachate, groundwater, wastewater treatment effluent, wastewater biosolids and in the drinking water of some cities. Pharmaceuticals can enter the environment in a variety of ways – some of the medications taken by people and animals escape to the environment by excretion. Unwanted medicines can also enter the environment when they are flushed down the toilet or tossed in the trash. Studies have shown that pharmaceuticals in our environment may have a negative impact some aquatic organisms and species.
Medicines have been detected in streams and other surface waters across the country, including Washington State. A 2007 King County study found the hormones ethynylestradiol (birth control pills) and estradiol (estrogen used in hormone replacement therapy) in some lakes and streams in King County. At some sites, these compounds were detected at levels found to cause effects on aquatic species in laboratory studies.
A 1999 U.S. Geological Survey of 139 streams in thirty states found at least one pharmaceutical in 80 percent of the streams tested. Acetaminophen (aspirin) was found in 23.8 percent of streams tested, the antibiotic trimethoprim in 27.4 percent, and codeine in 10.6 percent of streams tested. Concentrations of pharmaceuticals were generally low.1
Pharmaceuticals have been detected in the effluent from wastewater treatment plants. A 2004 study of groundwater and effluent from tertiary wastewater treatment plants in the Sequim-Dungeness region of the Olympic Peninsula detected acetaminophen (aspirin), codeine, metformin (diabetes medicine), sulfamethoxazole (antibiotic), salbutamol (albuterol), carbamazepine (anticonvulsant and bipolar disorder treatment), ranitidine (Zantac), estrone (hormone replacement therapy), trimethoprim (antibiotic), and ketoprofen (NSAID). Metformin was also found in groundwater and wells.
Disposing of medicines in the trash can lead to pharmaceuticals entering the environment through landfill leachate (the liquid resulting from the decomposition of solid waste). Leachate from landfills is typically pumped to the sanitary sewer system, and sewer treatment plants are not designed to remove pharmaceuticals. The Washington State Department of Ecology notes that pharmaceuticals in treatment plants eventually enter the aquatic environment in the treatment plant effluent or in the biosolids that are land applied across the state.
Garbage entering King County’s solid waste system is taken to the Cedar Hills Landfill, and leachate from that landfill is pumped to the sanitary sewer. Every year, about 100 million gallons of leachate is pumped from the Cedar Hills Landfill to the South Treatment Plant in Renton. Pharmaceuticals thrown into the garbage may make their way into this leachate. 2
Many homes and businesses in Washington State use an on-site septic system to treat their wastewater. If pharmaceuticals, particularly antibiotics, are flushed into a septic system, they may kill the bacteria that make the whole system work. Studies have demonstrated that pharmaceuticals can escape from septic systems to contaminate surrounding soil and groundwater. 3
Pharmaceuticals have been found in the drinking water drinking water that supplies 46 million people around the US.4 This isn’t a problem for the City of Seattle, which gets most of its drinking water from a protected watershed in the Cascade Mountains.
Studies indicate that pharmaceuticals in aquatic ecosystems have the potential to damage fish and other aquatic animals. For example, medicines can affect an organism’s sex. A Boulder, Colorado study found that sex ratios of fish upstream from a wastewater treatment plant were 45 percent female, while downstream from the plant 83 percent of the fish were female. Researchers speculate this could be associated with endocrine-disrupting compounds, including synthetic estrogen, found in treatment plant effluent.5
English sole from Puget Sound were surveyed for evidence of xenoestrogen (an estrogen compound) exposure, using vitellogenin (VTG) production in males as an indicator. Significant levels of VTG were found in male fish from several urban sites, especially in Elliott Bay along the Seattle waterfront. In addition, the timing of spawning in both male and female fish at the Elliott Bay sites appeared altered, suggesting that English sole in some areas of Puget Sound are exposed to estrogen compounds that cause biological effects6.
1 Kolpin,D.W.; Furlong,E.T.; Meyer,M.T.; Thurman,E.M.; Zaugg,S.D.; Barber,L.B.; Buxton,H.T. (2002). “Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance.” Environ Sci Technol. 2002 Mar 15;36(6):1202-11.
2 Barnes, K.K., Christenson, S.C., Kolpin, D.W., Focazio, M.J., Furlong, E.T., Zaugg, S.D., Meyer, M.T., and Barber, L.B. (2004). "Pharmaceuticals and other organic waste water contaminants within a leachate plume downgradient of a municipal landfill." Groundwater Monitoring & Remediation 24(2): 119-126.
3 Cherilyn Carrara, C., Ptacek, C., Robertson, W., Blowes, D. W., Moncur, M. C., Sverko, E., BackusFate, S. 2008. “Pharmaceutical and Trace Organic Compounds in Three Septic System Plumes, Ontario, Canada.” Environ. Sci. Technol., 2008, 42 (8), pp 2805–2811 (DOI: 10.1021/es070344q)
4 Mendoza, M., Associated Press (2008). “Recent tests detect pharmaceuticals in drinking water of 46 million Americans.” http://hosted.ap.org/specials/interactives/pharmawater_site/sept11a.html
5 Woodling, J. D, EM Lopez, TA Maldonado, DO Norris and AM Vajda. 2006,” Intersex and other reproductive disruption of fish in wastewater effluent dominated Colorado streams,” Comp. Biochem. Physiol.. Part C 144 (2006) 10 – 15.
6 Johnson, LL, DP Lomaxa, MS Myers, OP Olsona, SY Sola, S M O’Neill, J West and TK Collier 2008. Xenoestrogen exposure and effects in English sole (Parophrys vetulus) from Puget Sound, WA. Aquat. Toxicol. 88:29-38