The better our detection ability becomes, the more things we find in the water. One important group of those things is pharmaceuticals and their metabolites. Pharmaceuticals are specifically designed to affect the bodies, brains and behaviour of humans and other animals, at comparatively low concentrations. Some pharmaceuticals have synergistic effects with other pharmaceuticals, or with other common substances like grapefruit or Vitamin D. Could vulnerable humans be affected by chronic exposure to unplanned mixtures of pharmaceuticals (and other things) in water that is used for drinking, cooking, bathing etc.? And if so, should municipalities worry?
Do drugs in the water harm humans or other creatures?
Drugs get into water sources in many ways, including via excretion (human, animals), disposal of unused drugs into sewage systems or landfills, runoff from animal manure applied to fields, and from facilities that manufacture and package pharmaceuticals. As analytical methods improve, many drugs and their metabolites are now detectable, at very low concentrations, in wastewater and drinking water.
These drugs do have environmental effects. A study conducted in the Experimental Lakes Area of Northwestern Ontario found that adding minute concentrations of an estrogen used in many birth control pills to the lakewater led to feminization of male fathead minnows, followed by near extinction of the species from the lake. More recently, significant concentrations of antidepressant drugs were found in the tissue of brook trout exposed to wastewater that had gone through primary treatment; lower levels were noted in fish exposed to ozone-treated effluent. The same authors conducted an in vitro study that suggests that antidepressants (or other contaminants) in effluent may affect certain brain pathways in brook trout.
So far, limited evidence has not proven adverse human health effects. Ontario’s Ministry of the Environment is gathering information on pharmaceuticals that will be used to create a database that includes the concentration of these agents showing up in water, and other media. They just published results of a 2006 survey, which found pharmaceuticals and other contaminants in both source water and finished drinking water, but at levels they did not consider to be of concern.  One small study screened 19 drugs and their metabolites in drinking water, without finding adverse health effects, but recommended more research on other mixtures and sensitive populations. As usual, absence of evidence is not evidence of absence.
No standards yet
Responsibility for safe drinking water is shared among the three levels of government. The federal government is responsible for drinking water in certain areas, like First Nations communities and armed forces bases, as well as for regulating food safety, such as bottled water. Health Canada recently revised its (voluntary) Guidelines for Canadian Drinking Water Quality, developed by the Federal-Provincial-Territorial Committee on Drinking Water. These incorporate health and aesthetic considerations (e.g., odour, taste) and recommend standards for many chemicals (e.g., pesticides, fertilizers), but not pharmaceuticals.
Provinces and territories enact laws and regulations for safe drinking water, including setting standards for chemicals, which must be followed by water providers, including municipalities. Provincial and territorial governments also make laws and policies concerning protection of the environment, natural resources and our watersheds. Provinces typically use the federal guidelines in their own drinking water standards. So far, we don’t know of any that set standards for pharmaceuticals in drinking water.
Municipalities usually provide drinking water and wastewater services (at least in urban areas),  and typically implement these provincial/territorial policies. They enact by-laws that prohibit or limit discharges of many chemicals into sanitary and storm sewers. As yet, pharmaceuticals are not regulated through sewer by-laws. Nor is it obvious how such a bylaw could be enforced, especially for those drugs that pass through the human body.
Are municipalities at risk of liability?
If drugs in drinking water turn out to harm human health, municipalities can expect to be sued. Whether they can mount a successful defence will depend on good monitoring of the issue, taking appropriate actions when they can, and sticking together to set reasonable standards. An insurance pool wouldn’t hurt either.
Municipalities have some protections against civil lawsuit for nuisance, relating to leaks and discharges from their waterworks, based on statutory immunities adopted by each province in the late 1980s, after four Supreme Court of Canada decisions imposed huge liabilities on municipalities. However, claims for unsafe water are unlikely to be barred by these statutory immunities, which were not directed at the quality of water. When it comes to water safety, municipalities are much like anyone else who sells products intended to be consumed, and must provide water that is reasonably safe for consumption.
At a minimum, municipalities have to do everything they reasonably can to provide safe drinking water to their residents. (Statutory duties of care, such as the extremely demanding section 19 of Ontario’s Safe Drinking Water Act, 2002, will make this even harder.) This would include:
- · Pollution prevention: Do what you can to keep drugs out of the water supply. Like the City of Vancouver, mandate responsible disposal. Help educate consumers and health professionals not to pour surplus drugs down the drain, or put them in the garbage. Encourage product stewardship schemes by pharmacists and drug companies.
- · Transparency: Monitor and report levels of potential contaminants that could have adverse health effects, including pharmaceuticals where appropriate.
- · Keep current: Be aware when other levels of government proposal benchmarks for pharmaceuticals in water and when treatment options become available to remove them from drinking water and/or effluent. Keep your bylaws up to date.
- · Ask senior levels of government for action: The U.S. Association of Metropolitan Water Agencies is asking senior governments to set up a list of target drugs and focus research on effects on human health and aquatic life. It also suggests that the FDA mandate environmental assessments as part of the drug approval process; that guidance be developed concerning antibiotics in animal feed and production; and that a national program be developed to make it easy for consumers to dispose of unused medications.
We should be doing the same.
March 23 2011
 Phillips PJ et al. Pharmaceutical Formulation Facilities as Sources of Opioids and
Other Pharmaceuticals to Wastewater Treatment Plant Effluents. Environ. Sci. Technol. 2010, 44, 4910–4916. Available at http://pubs.acs.org/doi/pdf/10.1021/es100356f
 Kidd KA et al. Collapse of a fish population after exposure
to a synthetic estrogen. PNAS 2007 May 22;104(21):8897-8901
 Lajeunesse A et al. Distribution of antidepressants and their metabolites in brook trout exposed to municipal wastewaters before and after ozone treatment – Evidence of biological effects. Chemosphere 2011 Jan 4 [epub ahead of print]: 1-8
 Health Canada Pharmaceuticals and Personal Care Products in the Canadian Environment: Research and Policy Directions NWRI Scientific Assessment Report Series No. 8. 2007. See p. 19 At http://www.ec.gc.ca/inre-nwri/C00A589F-1CB5-4B81-93C9-8305E2BFEED3/ppcp-ppsp_2007-e.pdf
 258 grab samples collected over 16 months from untreated source waters and finished drinking water
 Kleywegt S et al. Pharmaceuticals, hormones and bisphenol A in untreated source and finished drinking water in Ontario, Canada — Occurrence and treatment efficiency. Science of the Total Environment 2011;409: 1481–1488
 Bruce GM et al. Toxicological Relevance of Pharmaceuticals in Drinking Water. Environ. Sci. Technol. 2010, 44, 5619–5626
 A summary table (December 2010) is available at http://www.hc-sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/water-eau/2010-sum_guide-res_recom/sum_guide-res_recom-eng.pdf
 Environment Canada. Wastewater management. http://www.ec.gc.ca/eu-ww/default.asp?lang=En&n=0FB32EFD-1 (“most wastewater systems are owned and operated by municipalities.” )
 Laurentide Motels Ltd. v. Beauport (Ville), , 1 S.C.R. 705; Tock v. St. John’s Metropolitan Area Board,  2 S.C.R. 1181; Just v. British Columbia,  2 S.C.R. 1228; Rothfield v. Manolakos,  2S.C.R. 1259
 e.g., Ontario’s Municipal Act, 2001 at s. 448(1)
 which will come into effect in 2013
 City of Vancouver. Solid waste by-law no. 8417. (At Schedule D, item 19 and Schedule E, item 25) Consolidation to December 14, 2010 at http://vancouver.ca/bylaws/8417c.pdf. Solid waste by-law bans consumers from disposing of unused drugs at curbside
 Fayerman P. Law banning household disposal of medications largely ignored, survey finds. Vancouver Sun January 12 2011. http://www.vancouversun.com/technology/banning+household+disposal+medications+largely+ignored+survey+finds/4100487/story.html