The following table summarizes the availability of information for each Water Quality indicator.

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

Denesuline elders from Black Lake and Fond du Lac have observed more sediment in the water near the west side of Lake Athabasca and raised concerns about the ongoing impacts of mining activities on water quality within their territories. The Lesser Slave Lake Cree have shared recent observations of dirty and murky water that were linked in one study to water diversion into Buffalo Bay on the west side of Lesser Slave Lake and sediment loading in rivers and streams due to runoff from nearby clear-cut areas. An analysis of water quality in tributaries to Lesser Slave Lake showed that suspended sediment levels were highest in western tributaries, especially East Prairie River, where extensive river channelization and straightening intended for flood control has modified river beds and increased river-bed erosion.

Fort Chipewyan elders have noticed an oily sheen on the surface of the Athabasca River when the river is calm and flowing smoothly and described how the water has a different taste than in the past. Black and rust-coloured water in streams and other waterbodies have been noted by the Lesser Slave Lake Cree. Changes in water taste and colour are often attributed to the rise of contaminants and sediments in natural waterbodies linked to industrial activity in the region.

Some Indigenous communities and local residents have observed an increased abundance of plant and algae growth (also called eutrophication) in lakes in the middle Athabasca. Studies of sediments in Baptiste Lake and Lac LaBiche have shown that these lakes were naturally eutrophic but that further lake eutrophication occurred during the 20^th century due to watershed development. In a study with the Lesser Slave Lake Cree, participants expressed concern regarding the ”greening” or eutrophication of Lesser Slave Lake and surrounding lakes witnessed in recent years. Similarly, an analysis of algae remains in Lesser Slave Lake sediments indicated higher algal productivity in the east basin after the 1960s. Residents of Baptiste and Island Lakes have also observed how blue-green algae blooms are more common in recent years and expressed concern for the impacts on fish and wildlife. Trend analyses on water quality data from 1979 to 2009 in Baptiste Lake and Gregoire Lake showed significant increasing trends in total phosphorus, the nutrient most often responsible for eutrophication, while data for Island Lake were not sufficient for trend analysis. Paleolimnological study in Baptiste Lake found that nutrient enrichment was related to watershed land use.

* Reproduced with permission from

Water samples taken at the Athabasca River at Old Fort, just upstream of the Peace-Athabasca Delta between 2014 and 2017, repeatedly exceeded the annual mean triggers (i.e., historical averages and medians) established by the Lower Athabasca Region Surface Water Quality Management Framework for dissolved compounds, such as dissolved lithium, dissolved uranium, potassium and sulphate. In addition, water samples consistently exceeded the annual peak triggers for dissolved uranium and in some years for other dissolved metals or sulphate. Such exceedances of typical historical levels are early indicators of increasing trends. As of fall 2019, continued investigations for parameters that have undesirable trends in the region were recommended: chloride, dissolved iron, dissolved lithium, total nitrogen, potassium, sulphate and dissolved uranium.

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.

Trend in October sulphate concentrations in Athabasca River above Athabasca Falls (2000-2018). Data from Environment and Climate Change Canada. Significance and slope of the trend were estimated using the Mann Kendall Trend Test. The Sen Slope (change in mg/L per year) and % change per year are displayed on the chart.

Trend in February dissolved arsenic concentrations in Athabasca River at Baseline 27 (2001-2019). Data from Environment and Climate Change Canada. Significance and slope of the trend were estimated using the Mann Kendall Trend Test. The Sen Slope (change in mg/L per year) and % change per year are displayed on the chart.

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.

Discharge from secondarily treated pulp mill and municipal effluent have caused localized issues of nutrient enrichment below wastewater outfalls in the Athabasca River. In addition, tributary and wastewater inputs cumulatively contribute to a decline in dissolved oxygen during winter along the length of the Athabasca River, mainly due to elevated biochemical oxygen demand in pulp and paper mill effluent. During the 2015 winter synoptic survey, dissolved oxygen concentrations in the Pembina and Muskeg rivers were below the short-term surface water quality guideline, and dissolved oxygen levels in the Firebag River were below the long-term surface water quality guideline.

As part of the Joint Oil Sands Monitoring Program set up in 2011, sixty-two tributary locations were sampled, of which fourteen were sampled at up to daily frequency during spring freshet and forty-eight sites monthly, seasonally, or annually. Data from 2012-2015 showed that concentrations of dissolved arsenic, dissolved selenium, total vanadium, total mercury and total polycyclic aromatic compounds followed hydrologic discharge with concentrations typically greatest during snowmelt (i.e., April-May). Patterns in methyl mercury were slightly different: concentrations increased during high flows but were greatest during mid-to-late summer months (late June to mid-August) when production via microbial pathways is highest in aquatic ecosystems.

Land cover in the Athabasca sub-basin is primarily forest (48%) with temperate or sub-polar needleleaf forest being the most prolific type. Shrubland (14%), grassland (13%) and water (12%) are also significant types of land cover in the basin. Cropland is localized in the Pembina watershed, where a significant portion of land surface is cultivated and pressure from agricultural land use on water quality was rated as “high” based on >60% agricultural land use.

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.

 

Land Cover Statistics for Athabasca sub-basin .Note that the wetland category is likely an underestimate, as shown in the table below.

Change in Land Cover 1990 to 2010

The largest degree of human land conversion between 1973/1974 and 2009 occurred in the Pembina watershed due to agricultural conversion (up to 20% change) and in the lower Athabasca watershed associated with Oil Sands development (8% change), as estimated from satellite imagery.

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%.

* Reproduced with permission from