Tracking Sources of Fecal Pollution in the Bow and Elbow Rivers: Implications for Drinking Water Risk Assessments in Calgary

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1 Tracking Sources of Fecal Pollution in the Bow and Elbow Rivers: Implications for Drinking Water Risk Assessments in Calgary *Norman F. Neumann, Norma J. Ruecker, Graham Banting, Joanne Matsune, Shannon L. Braithwaite, Nicholas Ashbolt, Mykola Sokurenko, Tarja Pitkänen, and Jorge Santo Domingo Office of Research and Development National Exposure Research Laboratory

2 Study Objective Characterize sources of fecal pollution affecting water quality within the Bow and Elbow Rivers (Bow River Watershed) Cryptosporidium Giardia Bacteroides (DNA and RNA) 1 Identify parasite risks to drinking water treatment plants (WTP) Bearspaw WTP [Bow River] Glenmore WTP (Elbow River) Environmental fate and modeling Quantitative Microbial Risk Assessment

3 Cryptosporidium Prevalence 0-20% 20-40% 40-60% 60-80% % Bearspaw WTP Glenmore WTP

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5 Table: Summary of Cryptosporidium occurrence at the various sampling sites in the Bow River Basin, including the drinking water treatment plants for the City of Calgary (Bearspaw [Bow River = green shading] and Glenmore [Glenmore Reservoir = red shading]) SITE Sample Size (n=) Prevalence (%)* Minumum (oocysts/100l) Cryptosporidium Maximum (oocysts/100l) Mean (oocysts/100l) Prevalence (%)* Minumum (cysts/100l) Maximum (cysts/100l) Mean (cysts/100l) Big Hill Springs Creek Bragg Creek near mouth Elbow River - Cobble Flats Elbow River - Weaselhead Footbridge Glenmore Reservoir Lott Creek near mouth Mclean Creek near mouth Millburn Creek Prairie Creek near Mouth Bearspaw (MV1) Bow River below Ghost Dam Ghost River - Benchlands Jumping Pound Creek Fish Creek at mouth Nose Creek at mouth Bow River at Highwood Bow River at HWY Giardia

6 Sources of Cryptosporidium in the Bow Avian River Watershed 2% Human 0% Cryptosporidium species/genotypes Number of water samples containing species/genotype Prevalence in watershed (n=298) C. andersoni 66 22% Muskrat II 10 3% Vole 6 2.0% W % Skunk 4 1.3% W % Muskrat I 3 1.0% Squirrel D 3 1.0% C. baileyi 2 0.7% Unknown genotype % Unknown genotype % C. ryanae 1 0.3% C. ubiquitum 1 0.3% W % Wildlife 32% NoRisk 31% Highrisk 0% Livestock 66% MediumRisk 1% LowRisk 68%

7 Sources of Giardia in the Bow River Watershed (2011) Giardia intestinals Assemblages/Species Number of water samples containing Assemblage/Species Prevalence in watershed (n=98) G. intestinalis Assemblage B % G. microti % G. intestinalis Assemblage A % Unknown % G.intes nalisassemblagea 7% Unknown 4% G.micro 33% G.intes nalisassemblageb 56%

8 Sources of Giardia in the Bow River Watershed (2011) NoRisk 37% HighRisk 63%

9 Giardiacysts/100L 01 Nov Association between Giardia Occurrence and Environmental Risk Factors Giardia occurrence displayed a cyclic pattern No pattern for Cryptosporidium Winter/Spring 01 Nov May Nov May Nov May Nov May Nov May Nov May Nov May Nov May 11 Glenmore WTP 01 May 03

10 Trend line Analysis of Giardia Occurrence. Glenmore WTP Bearspaw WTP 9

11 Modelling Giardia Occurrence at the Glenmore WTP Predicted Giardia Occurrence (cysts/100l) = (2.209-[0.4295*Rain] + [3.394*Snowmelt])-1 10

12 11 Parasite Risk (QMRA Health Canada Model

13 Estimating true Cryptosporidium Risk Estimating true Cryptosporidium Risk 12

14 Cryptosporidium Prevalence 0-20% 20-40% 40-60% 60-80% % Bacteroides (RNA markers at least 2 detections) Bearspaw WTP Human Cattle Muskrat Glenmore WTP

15 Summary Overall, the parasite risks to Calgary Drinking WTPs appear to be low. No C. hominis or C. parvum detected in the watershed over the last 3 years. High risk G. intestinalis (Assemblage A and B) frequently detected in watershed, but risks managed by operations. Occurrence of G. intestinalis linked to to snow melt (i.e., chinook) suggesting surface run-off» Glenmore ( ), Bearspaw ( )» Environmental shift noted in Bearspaw after 2007 correlated with summer season and rain in 2008 and onward.» Or...more young naïve animals on the landscape in late winter, early spring (e.g., calving)..or both (naïve animals and chinooks). 14

16 Summary Diffuse sources of human pollution (low level detectable by RNA analysis) as measured by Bacteroides. Complete watershed picture needs to consider distal (i.e., throughout the watershed ) and proximal sources (i.e., storm water) of pollution.» Watershed Safety Plans Monitoring can help establish a baseline framework for understanding risk, and consequently how development may affect microbial water quality» i.e., shift in Giardia occurrence in Bow River» Future development in the Elbow River watershed. 15