Source of Medicines in Water

In addition to the improper disposal of leftover and expired medicines through flushing and trash disposal, prescription and over-the-counter medicines may also get into our waterways through excretion from our bodies and through industrial pollution from drug manufacturing facilities.“Pharmaceuticals have become a significant water pollutant nationwide.” – President’s Cancer Panel

When you take a medication, not all of it gets absorbed into your body.  The leftover chemicals are excreted and flushed down the toilet. Since wastewater treatment systems are not designed to remove these chemicals, some pass through the treatment process and are discharged into our streams, lakes, rivers and bays.

Studies have not yet been able to determine how much of the drugs in our waterways are from bodily excretions versus improper disposal of unused medicines. However, we do know that about one-third of medicines sold to households in Washington go unused every year. While excretion is unavoidable, properly disposing of unused medicines is within your control if safe medicine take-back programs are available. You can prevent these medicines from getting into our waterways by disposing of them safely through medicine take-back programs.

Studies in the U.S.1 and around the world2 have found much higher than normal levels of medicines in waterways just downstream from drug manufacturing facilities. Our communities deserve safe and clean waterways!



1Phillips, P.J., Smith, S.G., Kolpin, D.W. Zaugg, S.D., Buxton, H.T., Furlong, E.T., Esposito, K. and S. Beverley. (2010).
Pharmaceutical Formulation Facilities as Sources of Opioids and Other Pharmaceuticals to Wastewater Treatment Plant Effluents.  Environmental Science and Technology, 44 (13): 4910-4916. 

2Larsson, Joakim, de Pedro, Cecilia, Paxeus, Nicklas (2007, September 30). Effluent from drug manufactures contains extremely high levels of pharmaceuticals. Journal of Hazardous Materials, 148(3): 751-755. .

3Estimates for unused containers of medicines in Washington state for 2009 were compiled from: Bush, P.J., Sanz, E.J. & Garcia, M. (1996).  Section II: Cross cultural reports. Medicines at Home:  the Contents of Medicines Cabinets in Eight Countries.  In Children, Medicines, and Culture.  New York, Pharmaceutical Products Press; Kaiser Family Foundation, State Health Facts. (2009). Total Number of Retail Prescription Drugs Filled at Pharmacies.