Water contamination and harm to fish & wildlife
When flushed or disposed of in the garbage, over-the-counter medications and prescription drugs can enter our waterways and potentially contaminate our drinking water supply. Most water treatment plants in the U.S. are not designed to filter out pharmaceutical compounds, so trace levels of prescription drugs are often detected in treated municipal water supplies. A 2002 study conducted by the U.S. Geological Survey found that 80 percent of streams tested across the country were contaminated with at least one pharmaceutical, personal care product, or other organic wastewater contaminant.[i] Although there are multiple sources of pharmaceuticals entering our waterways (e.g., human excretion and agricultural runoff), the improper disposal of medicines in the trash and by flushing represents a key source of environmental contamination that is preventable.
While no studies to date have conclusively linked ill effects on human health to long-term exposure to trace amounts of active pharmaceutical ingredients, studies have found pharmaceuticals present in some ecosystems at levels likely to harm entire populations of aquatic organisms.[ii] Certain types of pharmaceuticals, including analgesics/anti-inflammatories (e.g., Ibuprofen), antibiotics (e.g., azithromycin); anti-epileptics, and steroid hormones (e.g., prednisone), are toxic to marine animals.[iii] Fish are particularly susceptible to endocrine disrupting chemicals[iv] found in some pharmaceuticals; in fact, researchers have discovered that certain male fish exposed to such chemicals in U.S. waterways have become physiologically feminized.[v]
The potential impacts of increasing amounts of antibiotics in our waterways also represent a serious concern to public health. The accumulation of antibiotic contaminants in aquatic environments can contribute to the development of antibiotic resistant bacteria, which is recognized as an emerging threat.[vi] The presence of antibiotics in the natural environment could also trigger ecological impacts at the ecosystem level.[vii] The potential long-term impacts of this pollution on ecosystems remain almost entirely unstudied. We know that pharmaceutical compounds are specifically designed to affect biological organisms by treating undesired ailments; therefore, the ubiquitous and unchecked presence of these compounds in the environment should be minimized.
Trash Disposal is a Last Resort
In 2009, the Maine Department of Environmental Protection (DEP) collected and analyzed leachate (sludge) samples from three municipal solid waste landfills to assess the types and concentrations of pharmaceuticals that may be present. None of the landfill sites studied had been exposed to sludge from municipal wastewater treatment plants, which ensured that any pharmaceuticals present were linked to household trash disposal. The results of the study showed that compounds from over 40 pharmaceutical and personal care products (PPCPs) were found in landfill leachate[viii]. The study also concluded that the detected PPCP concentrations indicate the potential discharge of hundreds of pounds of PPCPs per year.”[ix] This data shows that while flushing medicines negatively impacts our waterways, there are risks to disposing of medicines with the household trash, as well. However, if there are no secure medicine drop-off sites or mail-back programs near you, you can discard leftover medicine in the trash by carefully following these guidelines.
[i] Kolpin, D.W., Furlong, E.T., Meyer, M.T., Thurman, E.M., Zaugg, S.D., Barber, L.B., Buxton, H.T. (2002, March 15). "Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams." Environmental Science & Technology, 36, no. 6, 1202-1211.
[ii] Ferrari, B., et al. (2003). "Ecotoxicological impact of pharmaceuticals found in treated wastewaters: study of carbamazepine, clofibric acid, and diclofenac.” Ecotoxicology and Environmental Safety 55: 359- 370; Henschel, K.-P., et al. (1997). "Environmental hazard assessment of pharmaceuticals.” Regulatory Toxicology and Pharmacology 25: 220-225; Jones, O. A. H., et al. (2002). "Aquatic environmental assessment of the top 25 English prescription pharmaceuticals.” Water Research 36: 5013-5022.
[iii] Hernando M.D., Mezcua M., Fernandez-Alba A.R., Barcelo D. (2006). "Environmental risk assessment of pharmaceutical residues in wastewater effluents, surface waters and sediments.” Talanta 69: 334-342.
[iv] Corcoran, J., Winter, M.J. and Tyler, C.R. (2010). "Pharmaceuticals in the aquatic environment: A critical review of the evidence for health effects in fish.” Critical Reviews in Toxicology 40,4): 287-304.
[v] Hinck, J.E., Blazer, V.S., Schmitt, C.J., Papoulias, D.M., Tillitt, D.E. (2009, October 19). "Widespread occurrence of intersex in black basses (Micropterus spp.) from U.S. rivers, 1995-2004." Aquatic Toxicology 95, 1: 60-70.
[vi] De Oliveria, A..J.F., Pinhata, J.M.W. (2008). "Antimicrobial resistance and species composition of Enterococcus spp. Isolated from waters and ands of marine recreational beaches in Southeastern Brazil.” Water Research 42: 2242-2250.
[vii] Martinez, J. (2009, November). "Environmental Pollution by Antibiotics and By Antibiotic Resistance Determinants.” Environmental Pollution 157, 11: 2893-2902. Doi:
[viii] Behr, R., Stahler,D., and Pistell, A. (2009). "Preliminary Characterization of the Pharmaceutical Content of Municipal Solid Waste Landfill Leachate from three landfills in Maine.” Maine Department of Environmental Protection.