Pharmaceuticals in Water and Wastewater- The City of Calgary's Experiences and Approach

Mei Chen and Klas Ohman
Laboratory Services, the City of Calgary Waterworks & Wastewater
Chris Metcalfe, Xiu-Sheng Miao and Shaun O'Toole
Water Quality Centre, Trent University, Peterborough, ON Canada

Abstract

Over the last two decades or so, pharmaceuticals have been detected in wastewater treatment plant influents and effluents, and in water supply systems. It is estimated that 50-90% drugs that are ingested may be excreted and subsequently discharged into wastewater-disposed system or environment [1]. Consequently, there is growing interest in Canada on the potential impact that drug residues might have on humans, and the environment [2,3]. Laboratory Services with the City of Calgary Waterworks and Wastewater Utilities has taken a proactive approach to this issue, and participated in a collaborative study with Trent University and also with Alberta Environment to conduct pharmaceutical testing on Calgary's wastewater influents and effluents, and on Calgary's water supply system. The purpose of the testing was to develop a better understanding of the risks posed by these compounds to Calgarians, and depending on the results, to develop any associated preventative measures.

In this recent study, wastewater samples from sewage treatment plants of Calgary were analysed for acidic and neutral drugs, and antibiotics from macrolide, quinolone, sulfonamide and tetracycline classes. Only some of the drugs were detected in the final effluents at part per trillion (ppt) levels and the concentrations of individual compounds were all below 1 ppb. The results of this study confirmed previous observations that some pharmaceutical residues seem to be removed very effectively in our advanced wastewater treatment plants, for reasons currently unknown to us.

To ensure that Calgarians were not at risk from their water supply as well, preliminary testing for estrogen-mimicking compounds was also undertaken on Calgary's source waters and its potable water. In all samples, estrogen-mimicking compounds were not detected at concentrations above the method detection limit of 1.4 ppt. Nonetheless, further investigation on pharmaceuticals and endocrine disrupting compounds in Calgary's surface water and finished drinking water is continuing, in conjunction with Alberta Environment, Trent University, the Institute of Ocean Sciences and EnviroTest Laboratories.

1. Raloff, J. 1998. Drugged waters - Does it matter that pharmaceuticals are turning up in water supplies? Science News 153, 187-189.
2. Metcalfe, C.D., B.G. Koenig, D.T. Bennie, M. Servos, T.A. Ternes and R. Hirsch. Occurrence of acidic and neutral drugs in the effluents of Canadian sewage treatment plants. Environ. Toxicol. Chem., Accepted.
3. Metcalfe, C. D., Moon, T., Trudeau, V., Struger, J. 2002. Distribution and effects of pharmaceutical drugs in the Canadian aquatic environment. Final Report on the Toxic Substances Research Initiative Project #337, Health Canada and Environment Canada.