Mainstem Benthic Invertebrates, Oil Sands Region

Mainstem Athabasca River Biomonitoring Benthic macroinvertebrates, comprising insects, crusteaceans, molluscs and worms, represent a group of organisms used widely in environmental monitoring programs as early warning indicators to assess the effects of change in water quality or physical habitat conditions on aquatic ecosystem health. An interpretive report (Culp et. al., 2018) was released in 2018 which included assessments of the benthic and supporting data from 2012-2015. An excerpt from the executive summary regarding the mainstem benthic invertebrate results is provided below and the full report can be found online at https://open.alberta.ca/publications/9781460140314). “The Lower Athabasca River main stem generally has good ecological condition with intolerant taxa, such as Ephemeroptera,Plecoptera and Trichoptera (EPT), found in large abundances at all sampling sites. Nevertheless, the middle river reaches between M3 and M7C show signs of mild environmental stress that should be examined more closely through focused studies designed to tease apart the combined effects of nutrient and contaminant stressors. Definitive statements on the linkage of environmental divers to ecological change in reaches M3 to M6 are not yet possible. Future assessments should focus on examining associations between the longitudinal benthic pattern and key supporting variables (e.g., nutrients, polycyclic aromatic compounds (PACs), vanadium). Monitoring designs should include sediment chemistry and Semi-Permeable Membrane Device (SPMD) deployments as these appear to measure critical environmental variables associated with patterns of benthic assemblage. Relative to current macroinvertebrate assemblages, historical assemblages were composed of more tolerant taxa (e.g., chironomids). Although this suggests a reduced ecological condition in the LAR at that time, this trend is most likely an artifact of sample location in the earlier studies. Analyses to date indicate that benthic assemblages in cobble habitat provide better resolution for detecting ecological change between M0 to M9. Ongoing monitoring of benthic assemblages using kick net approaches in cobble reaches of the LAR main stem are required to detect change associated with human activities. Additional reference sites between M0 and M2 are recommended to improve the ability to detect change from the reference condition.” Biomonitoring Water Quality In addition to collecting benthic invertebrate samples, supporting water chemistry samples were taken on the same date. Verified and validated water quality data from fall of 2011 through to the fall of 2017 collected to support Invertebrate and Ecosystem Health studies. Data was collected at up to twenty-one sites on the mainstem of the Athabasca River and over 100 sites on its major tributaries. The data include measures of nutrients, metals (dissolved and total), polycyclic aromatic hydrocarbons and major ions.