Changes in water quality have been reported by Indigenous communities and through scientific studies in some waterbodies in the Athabasca sub-basin. Indigenous communities have observed an increase in contaminants and sediment in lakes and rivers in the middle and lower Athabasca River and a change in the taste and colour of the water. These changes are thought to be associated with increased industrial activities, particularly oil sands mining and forestry, but studies also show localized influence of river channelization and straightening on water quality in the Lesser Slave watershed. Increases in blue-green algae blooms and nutrient enrichment in some lakes have been reported in studies by scientists, Indigenous communities, and local residents. Human footprint has increased over time and the downstream effects of industrial development remain a concern for local communities and there are significant concerns for how water contamination will continue to affect water quality and ecosystem health.
The following table summarizes the availability of information for each Water Quality indicator.
Indigenous Knowledge Information and Data
Indigenous Knowledge Availability in Public Sources1
Science Information and Data
Science Data Availability2
Local observations and oral histories of good water, poor water, seasonal differences, land-based consumption practices
Many observations from several locations.
Ambient surface and ground water concentrations
Many datasets and reports available.
Not assigned to a Sign or Signal
Relative abundance of aquatic macroinvertebrates
Several datasets and reports available.
Land Use Changes
Stories and oral histories of land use cover and practices
Many observations from several locations.
Map and statistics of current vs. past land cover and land use
Current and past data available.
Not assigned to a Sign or Signal
Volume of effluent discharges
Data available but not summarized for this report.
1 Qualifiers for the availability of local and Indigenous Knowledge observations in publicly available sources: Limited = 1-2 observations; Some = 3-4 observations; Many = 5 or more observations
2 Qualifiers for the availability of science data in publicly available sources: Low = Individual studies or locations; Many = Network of monitoring stations across the basin
Increases in contaminants, sediments, and concentrations of many substances in tributaries downstream of oil sands development have been observed in some waterbodies in the Athabasca sub-basin. More frequent blue-green algae blooms in some lakes have also been observed.
Tributary concentrations of many parameters were greater at sites downstream of oil sands development near their confluence with the Athabasca River. Analysis of historical water chemistry data (1972-2010) showed that concentrations and loads of total vanadium, dissolved selenium and dissolved arsenic were greater downstream of development compared to reference sites in the Lower Athabasca oil sands region. A case study conducted on the Muskeg River (1972-2009 data) showed that concentrations and loads of the same three elements were greatest during the early land-clearing stage of mine development, with dissolved selenium remaining elevated during the subsequent expansion stage. During the first three years of the new Oil Sands Monitoring program from 2011 to 2014, selenium was the only parameter that showed a clear increasing pattern in the Athabasca River mainstem from upstream of the Oil Sands to downstream, during spring freshet. Analysis of Environment Canada data downstream of oil sands development showed an increasing trend from 2000 to 2018 in dissolved selenium for August of 0.001 ug/L per year (0.75% per year, n=31, p=0.001) and in total selenium for August of 0.001 ug/L (0.65% per year, n=30, p=0.045).
Many Aboriginal communities have observed a marked decline in water quality in the Athabasca River over the last 50 years,
Residents and users of both Baptiste and Island Lakes are concerned that frequent blue-green algae (cyanobacteria) blooms are adversely affecting fish and wildlife
Extensive (monthly) sampling from 2012 onward and data analysis from 2012 to 2015 as part of the Canada-Alberta Joint Oil Sands Monitoring Program showed that increasing trends in many dissolved substances were associated with reductions in flows or part of a regional trend also seen in other major rivers not affected by oil sands development. Analysis of data from 2000 to 2019 at Environment Canada monitoring stations along the Athabasca River indicated increasing trends for indicators of ionic strength for many months at all locations (this study). For example, mean monthly total hardness increased by 0.5 mg/L (0.4%) to 1.6 mg/L (1.5%) per year, pH increased by 0.004 (0.05%) to 0.042 (0.5%) per year, sulphate by 0.2 mg/L (0.7%) to 1 mg/L (3%) per year and dissolved uranium by 0.03 ug/L (0.8%) per year to 0.01 ug/L (3.4%) per year for different monthly datasets. Increasing trends in mean monthly concentrations for other dissolved metals were mainly observed downstream of the oil sands region, such as for dissolved aluminum by 0.5 ug/L (8.5%) to 3.1 ug/L (5.9%) per year, dissolved arsenic by 0.005 ug/L (0.9%) to 0.015 ug/L (4.2%) per year, dissolved iron by 2 ug/L (20%) to 9 ug/L (4.8%), and dissolved cobalt by 0.001 ug/L (1.2%) to 0.004 ug/L (6.5%) per year (this study). Sulphate remained well below the Alberta surface water quality guideline in all these samples, while dissolved aluminum and iron were close to or exceeded the guideline occasionally at the site downstream of oil sands development. Alberta Environment and Parks data analysis of water quality data from Athabasca River at Town of Athabasca also showed increasing trends in pH, dissolved solids, sulphate and some major ions.
Long-term trend analysis of data from Old Fort showed that for 2000- 2014 several parameter concentrations declined, including dissolved phosphorus (0.3 ug/L per year) and ammonia (degree of decline not reported). Total phosphorus concentrations, which previously had been increasing, were stable from 2000 to 2018 (this study). This stabilization was attributed to treatment upgrades at the Fort McMurray wastewater treatment facility and pulp and paper mills upstream and the subsequent reductions to total loadings within the Athabasca River basin. Water quality studies in the Athabasca River in the early 1990s recorded large effects from phenols, chlorinated phenols, resin acids, and trace organics. These were not observed during a 2015 winter synoptic survey, possibly indicating an improvement in water quality conditions owing to more stringent effluent regulation and advancements in technology and wastewater treatment processes within the pulp and paper industry.
Sub-basin-wide trends in benthic invertebrate communities reflect natural factors, but benthic abundance increased locally in response to point-source discharges.
Oil Sands Monitoring from 2012 to 2014 indicated that the lower Athabasca River mainstem generally has a good ecological condition with a high abundance of sensitive benthic invertebrate taxa at all sites. However, the sites in middle reaches (near large surface mines) show signs of mild environmental stress. Good ecological condition in lower Athabasca River tributaries was generally indicated by the presence of intolerant taxa (Ephemeroptera, Plecoptera, Trichoptera) across sites. However, assemblages in areas with increased disturbance were divergent from reference conditions, which suggest that communities in the lower reaches of the major tributaries are experiencing potential cumulative impacts of on-going and expanded mining development.
Localized areas of nutrient enrichment are a concern: This is particularly significant downstream of municipal and industrial point source discharges in major municipalities (i.e. Hinton, Whitecourt, Athabasca and Fort McMurray). For example, relatively low increases in phosphorus from inputs of municipal wastewater effluent was observed to result in a 4- to 30-fold increase in the abundance of benthic algae and macroinvertebrates downstream of Jasper, Alberta.
Basin-wide spatial trends in invertebrate communities reflect natural factors: An assessment of various benthic invertebrate data sets indicated that longitudinal trends in benthic invertebrates in the mainstem and tributaries of the Athabasca River reflect natural changes in geomorphologic and hydrologic factors associated with river size and gradient. Impacts of anthropogenic disturbance in the form of municipal wastewater, industrial point-source inputs, diffuse agricultural inputs, and disruptions in flow regimes were not detected at this scale. Given the multiple lines of evidence about point source impacts on benthic invertebrates in the Athabasca River, this may be a methodological limitation of combining multiple datasets over a large region in this specific study.
Contamination of aquatic ecosystems and generally lower water levels are leading to changes in Indigenous land use practices in the Athabasca sub-basin. Land cover in the sub-basin is dominated by forests; however, there is significant human footprint due to forestry in the entire sub-basin, agriculture in the Pembina watershed and surface bitumen mining footprints in the lower Athabasca.
Minor recent basin-wide increase in cropland and urban land cover. Cropland and urban land cover increased and natural cover decreased slightly from 1990 to 2010, but these changes only represented 0.5% of the Athabasca sub-basin surface area. Settlement areas more than doubled, increasing from 0.2% to 0.5% of the sub-basin, while cropland increased from 3.5% to 3.6% in the sub-basin. These changes mostly displaced forest and wetlands but didn’t change their overall percentage due to their much larger overall area in the sub-basin (Agriculture Agri-Food Canada).
Percent Land Cover
Change in Land Cover 1990 to 2010 (Agriculture and Agri-Foods Canada)
Land Cover Type
Area 1990 (km2)
Area 2010 (km2)
1990 % cover
2010 % cover
Forest / Trees
The total area of human footprint in the Lower Athabasca Region increased by 3.2 percentage points from 5.5% in 1999 to 8.7% in 2017. This increase was driven by the expansion of the forestry footprint, which more than doubled in size during this time from 1.0% to 2.5%. However, this increase in forestry footprint is lower (1.2%, from 0.6% to 1.8%) when recovery of regenerating forest is included. The remaining human footprint categories each had small increases of < 1.0 percentage point between 1999-2017, with energy footprint showing the next largest increase from 1.0% to 1.8%.
The total area of human footprint in the Upper Athabasca Region increased by 7.7 percentage points from 22.4% in 1999 to 30.1% in 2017. This increase in human footprint was driven by the expansion of forestry footprint, which more than doubled in size during this time from 5.4% to 11.8%. However, this increase in forestry footprint is lower (5.4%, from 3.0% to 8.4%) when recovery of regenerating forest is included. The remaining human footprint categories each had small increases of < 1.0 percentage point between 1999-2017, with agriculture footprint showing the next largest increase from 12.8% to 13.5%.
Effluent volume data were not collected but point sources discharge a variety of substances of potential concern for receiving aquatic environments.
Habitat & Species