Montreal, January 26, 2009 – A study conducted by Université de Montréal
researchers on downstream and upstream water from the Montreal wastewater
treatment plant has revealed the presence of chemotherapy products and certain
hypertension and cholesterol medications.
Bezafibrate (cholesterol reducing medication), enalapril (hypertension
medication), methotrexate and cyclophosphamide (two products used in the
treatment of certain cancers) have all been detected in wastewater entering the
Montreal treatment station. However, only bezafibrate and enalapril have been
detected in the treated water leaving the wastewater treatment plant and in the
surface water of the St. Lawrence River, where the treated wastewater is
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. A significant proportion of the drugs consumed are excreted by the
human body in urine and end up in municipal wastewater. Chemotherapy products,
such as methotrexate, are excreted by the body practically unchanged (80 to 90
percent in their initial form).
Chemotherapy for fish?
The pharmaceutical compounds studied were chosen because of the large
quantities prescribed by physicians. "Methotrexate and cyclophosphamide are two
products very often used to treat cancer and are more likely to be found in
water," says Sébastien Sauvé, a professor of environmental chemistry at the
Université de Montréal. "Even though they treat cancer, these two products are
highly toxic. This is why we wanted to know the extent to which the fauna and
flora of the St. Lawrence are exposed to them."
Method and quantities
Professor Sauvé's team validated a rapid detection method (On-line
SPE-LC-MS/MS ) (1) for pharmaceutical compounds under study in the raw and
treated wastewater of the Montreal wastewater treatment plant.
The quantities of bezafibrate and enalapril detected in the raw wastewater,
treated wastewater and surface water at the treatment station outlet are
respectively 50 nanograms per litre, 35 ng L and 8 ng L for bezafibrate and 280
ng L, 240 ng L and 39ng L for enalapril.
"All in all, these quantities are minimal, yet we don't yet know their
effects on the fauna and flora of the St. Lawrence," Professor Sauvé explains.
"It is possible that some species are sensitive to them. Other ecotoxicological
studies will be necessary. As for the chemotherapy products detected in the raw
wastewater but not in the treated wastewater, one question remains: did we not
detect them because the treatment process succeeded in eliminating them or
because our detection method is not yet sophisticated enough to detect them?"
A new threat to the aquatic environment
The release locations of wastewaters treated by the treatment stations are
the main source of drug dispersion into the environment. Because of their high
polarity and their acid-base character, some of the pharmaceutical compounds
studied have the potential to be transported and dispersed widely in the aquatic
environment. In Montreal, the wastewater treatment station treats a water volume
representing 50 percent of the water treated in Quebec and has a capacity of
about 7.6 million cubic metres per day, making it the largest physicochemical
treatment station in the Americas. This is why it is important to develop a
simple, rapid, precise and inexpensive method, Professor Sauvé points out.
This study was published in the
Journal of Environmental Monitoring
and produced by researchers from the Department of Chemistry of the Université
de Montréal and the Environment Canada Aquatic Ecosystem Protection Research
Division. It was funded by the Natural Sciences and Engineering Research Council
of Canada, the National Council for Science and Technology of Mexico, the Canada
Foundation for Innovation, the St. Lawrence Action Plan and Health Canada's
Chemicals Management Plan.
(1)On-line solid-phase extraction liquid chromatography coupled to
polarity-switching electrospray tandem mass spectometry
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