Pathogenic Organisms

Gaps in Pathogen Detection

Parasites and viruses are detectable in most secondary treatment effluents, and a single sewage treatment plant can introduce large numbers of pathogens to a water body.³⁰ They can be viable for long periods of time in the environment, and bacterial fecal indicators do not provide adequate information on their survival and inactivation during wastewater treatment.³¹ Regulatory agencies need additional data to construct models that estimate the potential risk for humans and wildlife exposed to microbial pathogens at beaches, in waters used for swimming, and in intake water for water treatment plants.

Local water authorities and private citizens do not typically monitor private wells for microbial contamination, leaving a large number of people potentially vulnerable to both chemical and microbial contamination.³² In the Summary Report of the Walkerton Inquiry (2002), Justice O’Connor recommended that the Ontario Clean Water Agency and municipalities better educate and inform citizens using private wells about the types of contaminants to which they could be exposed. ³³ Senior orders of governments could provide additional resources to local health authorities so that private sources of drinking water can be evaluated for their safety.

Even when waterborne illness occurs, detecting it can be difficult. As a result, instances of disease caused by pathogens in water are probably under-reported to public health officials.³⁴ Most people afflicted by gastrointestinal illness caused by pathogens in water will experience flu-like symptoms several days after exposure, rarely suspecting the ingestion of contaminated water, and often assuming the illness is the result of food poisoning. Consequently, disease outbreaks are not detected consistently, rarely properly identified even by clinicians, leading public health agencies to underestimate total disease incidence from contact with or consumption of contaminated water. ³⁵ As a result, the extent of waterborne infectious disease in the United States and Canada cannot be fully known.³⁶

Clearly, environmental regulators and health officials need new tools to monitor and study microbial contaminants and their effects on human populations.³⁷ Fortunately, advances in molecular biology now enable researchers and epidemiologists to better track waterborne diseases and identify their sources.