BY Joanna Wilson
ON March 22, 2018
We all do it when we aren’t feeling well. A headache, a cold, an allergic reaction and we take some medication to feel better. Other than thinking about how well these medications are relieving symptoms, I’ll bet you never think about what happens to medications after you take them. At some point, the pharmaceuticals you take will exit your body and enter municipal sewers and wastewater treatment facilities. Plenty of research tells us that these drugs are then finding their way into our water – surface water, ground water, and even our drinking water. While the amounts are small, a complex soup of drugs are making their way from our homes into the environment. This is increasingly being recognized as an important and emerging environmental concern.
So how many different drugs are found in surface water? Basically everything we commonly take as medication can be found in water. Antibiotics, pain relievers, lipid lowering drugs, heart medication, anti-depressants, hormones… It is a very long list of medications for every common medical condition and includes both prescription and over the counter medication. The exact list and concentration varies from place to place, but the list is dominated by the most common drugs we use in every day life. Hamilton Harbour is no different. Several studies have found a complex mixture of human drugs in our local waters, originating from our wastewater treatment plants. You might think that it doesn’t really matter, since the concentrations are quite low, only in the nanogram to microgram per litre concentration range (around 1 part per trillion to 1 part per billion) and that seems like tiny amounts to most people. Yet, research in my lab, and many others, suggests that even at these low concentrations, human drugs may cause effects in aquatic species such as fish.
We have to realize that drugs are chemicals that have high activity in low amounts. This high activity is great, since it ensures that we only need a small pill to treat our medical conditions, but it also means that having a small amount in water may still pose a risk to aquatic species. The reason is because the drug targets in humans are typically also found in other animals. For fish, their major organ systems and physiology are really very similar to that of humans. Studies in the zebrafish tell us that fish share about 84% of the genes known to have a role in human health. This strongly argues that most, if not all, human drugs are likely to have an effect in fish. In my lab, we have been studying the effects of several human drugs that are commonly found in surface water from Hamilton Harbour, Lake Ontario, and freshwater throughout the US, Canada and Europe. We have focused on drugs from different classes, including pain relievers, anti-depressants, lipid lowering drugs, and anti-epileptics. We have found several human drugs lower reproduction in fish, resulting in fewer offspring from fish exposed for several weeks.
As we celebrate World Water Day, we need to think about the importance of access to clean, fresh water. I encourage you to think about what you do to conserve and protect our vital water resources. Pharmaceuticals are an emerging concern for water and it is a major challenge to remove these compounds from wastewater effluent, since treatment plants were not designed for this task. New technology solutions will be needed to help, but we must all do our part. Human use is the primary route for drugs to enter the environment. We need to understand that when we use drugs, they don’t disappear but end up in our toilets and eventually in our water. Expired or unneeded medications should not go down our toilets. Ontario’s Medications Return Program will take back prescription, over the counter, and natural health products to ensure they are destroyed properly and don’t end up in the environment. Since only a fraction of unused drugs are disposed of correctly, this could be a significant step towards protecting our water resources. The fish don’t need your medication, but the pharmacy will gladly take it.