Environmental hazards of pharmaceutical products

Other Names:
Environmental pollution by drugs
Trace medicines in the environment
Pharmaceutical pollution
Drug contamination of the environment

Pharmaceutical drugs given to people and to domestic animals – including antibiotics, hormones, strong pain killers, tranquilisers and chemotherapy chemicals – find their way into the food chain, the soil and water.  No drug has ever been refused entry into the market based on estimated environmental concentrations and no actual testing is conducted after a drug is marketed to see if the environmental concentration was estimated correctly. Controls on drugs have been the brief of health departments, which are concerned only with the effect of drugs on the humans to which they are administered.

Large quantities of drugs are excreted by humans and domestic animals, and are distributed into the environment by flushing toilets and by spreading manure and sewage sludge onto and into soil. Some drugs reach the environment in their original form, and sometimes as by-products broken down by the human body. Some of the metabolites are more reactive and sometimes more toxic than the parent drug. Pharmaceuticals can be present in the environment at concentrations similar to those of pesticides, and like them they can be highly mobile and persistent.


Drugs are designed to have particular characteristics. For example, 30% of the drugs manufactured between 1992 and 1995 are lipophilic, meaning that they tend to dissolve in fat but not in water. This gives them the ability to pass through cell membranes and act inside cells. Unfortunately, it also means that, once they are excreted into the environment, they enter food chains and concentrate as they move upward into larger predators. Many drugs are also designed to be persistent, so that they can retain their chemical structure long enough to do their therapeutic work. After they are excreted, such drugs also tend to persist in the environment.

When a human or an animal is given a drug, anywhere from 50% to 90% of it is excreted unchanged. The used portion is excreted in the form of metabolites – chemicals produced as byproducts of the body's interaction with the drug. Researchers report that some of the metabolites are more lipophilic and more persistent than the original drugs from which they were derived. Because of the complexity of the chemistry involved in drug metabolism, and the interactions of the metabolites with the natural environment, researchers say is it practically impossible to estimate predicted environmental concentrations of any medical substances with available knowledge.


Drug residues seep from a marine waste dump of the north coast of Puerto Rico, where millions of litres of pharamaceutical waste were tipped into the sea annually between 1972 and 1983.

Related UN Sustainable Development Goals:
Problem Type:
D: Detailed problems
Date of last update
15.05.2019 – 21:43 CEST