Virus Testing in Groundwater Supply Sources using genetic testing, a new innovative approach
Organization: Southeast Kelowna Irrigation District
Historically, technology for virus testing has not been available. Unlike bacteria, viruses are host-specific, and this makes them difficult to grow in a lab. However, recent advances in genetic methods have made testing for viruses possible. Viruses can originate from leaking septic fields and sanitary lines, and are pathogenic at very low concentrations; even a small amount of virus “leaking” into a preferential pathway can cause illness. Viruses are inactivated by chlorination or UV treatment; however, chlorination treatment requires contact time and this sometimes requires a reservoir. Reservoirs and UV treatment systems are costly. Moreover, some communities are opposed to chlorine being added to their drinking water. The knowledge gained from this testing has provided SEKID with a better understanding of its groundwater quality, and aids SEKID and the public it serves make better informed land-use and water-treatment decisions.
A sampling program was completed for viruses, protozoa, and select organic wastewater indicators at three well sites in Okanagan (Oliver, Penticton, and Kelowna) over a period of 12 weeks. The following conclusions are based on the results of this sampling program:
SEKID’s O’Reilly well was determined to be at low risk to pathogens up to a pumping rate of 17.9 L/s and a 1:5 return period precipitation event.
Lot 78 Well B (new) at PIB was determined to be at low risk to pathogens; however, no pumping records were available for the study period and less than a 1:2 return period for storms occurred during the 8-week sampling period; therefore, it may be prudent to assume an at-risk to viruses’ determination.
MW002 at OIB was determined to be at risk to viruses and at low risk to protozoa. Although the virus sampling program over 8 weeks in spring 2015 showed no positive results for viruses, no significant storm events occurred during the sampling program. Moreover, based on the hydrogeological setting and the proximity to sources of viruses, the well is considered at risk to viruses.