The use of pharmacological agents has increased rapidly during the last decades. Cardiovascular diseases and cancers are the most prevalent chronic conditions in developed countries. Large amounts of chemotherapeutic drugs and medications to manage high blood pressure and elevated cholesterol levels are being used to treat patients everyday. These drugs make us feel better and keep ailments at bay but have we ever wondered where do they end up after being excreted from the body? Although drugs are taken up and metabolized by the human body, a large amount of these are excreted through the urine and the feces.And they eventually end up in our waste water that goes to the water treatment plants.
So far so good. However, how efficient is our water treatment system in filtering out these chemicals?
This was the question that researchers from the University of Montreal wanted to answer. The researchers sampled water in the St. Lawrence River downstream and upstream of the wastewater treatment plant of the city of Montreal. They checked for the presence of chemotherapy products and certain hypertension and cholesterol medications using the “rapid detection method On-line SPE-LC-MS/MS (On-line solid-phase extraction liquid chromatography coupled to polarity-switching electrospray tandem mass spectometry).” The compounds they specifically check for were
- Bezafibrate, a cholesterol-lowering rug
- Enalapril, a drug against hypertension
- Methotrexate, a chemotherapy agent
- Cyclophosphamide, also a chemotherapy agent
These four drugs are routinely prescribed in large amounts by doctors in the area.
The results of the study show that all four drugs were detected in the untreated waters upstream of the water treatment plant. However, only bezafibrate and enalapril were detected downstream in the treated waters leaving the plant. The results indicate the following:
- Large amounts of pharmacological products enter the St. Lawrence River.
- The water treatment system is efficient enough to get rid of the chemotherapy drugs but not the anti-cholesterol or anti-hypertension drugs.
The researchers, however, think that it is too early to conclude about the efficiency of water treatment in taking out chemotherapeutic compounds. It is possible that they might still be there but in very minute amounts undetectable by the current analytical methods used.
According the university press release
“This study was conducted due to the sharp rise in drug consumption over the past few years. In 1999, according to a study by IMS Health Global Services, world drug consumption amounted to $342 billion. In 2006 that figure doubled to $643 billion.”
The next questions to be answered are:
- How do these chemicals affect the aquatic environment and the plants and animals living in it?
- How much of these chemicals are present in our drinking water?