How Pharmaceuticals Enter the Environment
On this page:
- Overview
- Medicines Placed in the Trash Can Enter the Environment via Landfill Leachate
- Flushing Leftover Medicines Contaminates our Environment
- Studies
Overview
Pharmaceuticals can enter the environment in different ways: some unintentional, some intentional. One source of pharmaceuticals in the environment is human excretion. Medicines that we take are not entirely absorbed by our bodies; a portion is excreted into wastewater. Some of the other sources of pharmaceuticals in the environment include:
- Landfill leachate.
- Flushing leftover medications.
- Wastewater treatment plants.
The diagram below illustrates the ways that pharmaceuticals may enter the environment via sources two and three above. The rest of this webpage provides more detail about how pharmaceuticals can enter the environment from these three sources.
Medicines Placed in the Trash Can Enter the Environment via Landfill Leachate
While modern municipal solid waste landfills in the U.S. are lined and employ leachate collection systems to prevent groundwater contamination, this study shows that the collected landfill leachate can contain pharmaceuticals. Collected landfill leachate is generally sent to wastewater treatment operations where, despite being treated for many pollutants, the pharmaceuticals typically pass through and are discharged to surface water.
Flushing Leftover Medicines Can Contaminate our Environment
Septic Systems
In homes that use septic tanks, prescription and over-the-counter drugs flushed down the toilet can leach into the ground and seep into ground water.
Municipal Sewage
Most wastewater treatment operations discharge treated water to surface water like rivers and lakes. In cities and towns where residences are connected to wastewater treatment plants, prescription and over-the-counter drugs poured down the sink or flushed down the toilet often pass through these treatment systems and enter surface water. Water treatment plants are generally not equipped to remove medicines. The treated wastewater that the treatment plant discharges into surface water then flows downstream where other communities may use the same body of surface water as a source of drinking water.
Wastewater Treatment Plants
Wastewater from households connected to municipal sewer systems flows to publicly owned treatment works (sometimes also referred to as wastewater treatment plants) for treatment. Leachate that is collected from landfills also goes to POTWs for treatment. Traditional wastewater treatment operations technologies implemented at POTWs are designed to remove conventional pollutants, such as suspended solids and biodegradable organic compounds. While POTWs may remove some pharmaceuticals incidentally, many pass through and enter the environment because POTWs are not designed to remove pharmaceuticals. While some POTWs may have implemented advanced treatment technologies, even these technologies are not specifically designed to remove pharmaceuticals.
Studies
EPA released a study in 2009 where we analyzed over 100 chemicals (including some pharmaceuticals) in the influent and effluent at nine POTWs. The study shows that the capabilities of treatment technologies currently employed by most POTWs do not include treatment to remove active pharmaceutical ingredients.
In a study published in 2014, EPA measured concentrations of 56 APIs in effluent samples from 50 large POTWs across the country and discovered at least one API in each sample.
Some pharmaceuticals are specifically designed to be resistant to biologic breakdown, which makes them even more difficult to remove from wastewater. As stated in EPA’s 2009 Health Services Industry study, ‘‘synthetic compounds, such as pharmaceuticals, are often manufactured to be resistant to metabolic transformation. As a result, some pharmaceutical compounds that are present in the influent to POTWs may pass through treatment systems at conventional POTWs and discharge to receiving waters.’’