Fish Toxicology, Oil Sands Region

Oil Sands Sediment Exposures of Embryo-larval Fathead Minnows

Dataset contains laboratory-studied fathead minnow egg and larval survival rates when exposed to sediments collected from 18 sites in the Athabasca watershed (2010-2014).

A controlled laboratory study examined the impacts on fathead minnow eggs and larval development when exposed to collected sediments at concentrations of 1, 5 and/or 25 g/L. Sediments and water were renewed daily, and eggs were assessed as they hatched (in about 5 days), and as the larval fish grew to 8-9 days post hatch (dph), and 15-16 dph. The data in the file present the mean survival (and standard deviation). Two sediment sites caused decreased survival of fathead minnow fry: The Ells River lower site, and the Steepbank River Lower site. These data show that sediment from these sites can affect larval fish survival in the lab. The next steps are to compare these findings to the health data from wild fish collected from these same tributary sites.

Toxicity Testing of Groundwater near the Oil Sands Development

Dataset contains toxicity studies of groundwaters collected near the Athabasca and Ells rivers. Groundwaters were collected in the summer of 2013 from 4 sites below the riverbeds at depths of 0.5 to 1 metre. Sites were chosen to represent groundwaters close to oil sands tailings ponds and further from tailings ponds and mining activities.

Under controlled laboratory conditions, fathead minnow eggs were exposed for 5 days (until hatch) to the groundwaters at standard dilution concentrations of 6, 12, 25, 50, and 100% of the groundwater sample to compare egg and larval fish survival. The data presents the average survival until hatch of 3 repeated exposures (and standard deviation) and 9 repeated exposures for controls.

Some groundwater is toxic to minnows and some is not. No correlations were found between toxicity and proximity to a tailings pond.

Assessing Toxicity of Oil Sands Related Substances

Laboratory fish were exposed to melted snow from sites located close to oil sands mining and upgrading facilities and from sites far away from mining activities to assess the toxicity of substances found in the snow. In addition, river waters, bed sediments, suspended sediments, groundwater and atmospheric depositional samples (pre-melt snow collections) were also tested for toxicity.

Fish exposed to undiluted snowmelt showed biological effects. Fish exposed to river water from the region collected during snowmelt conditions showed no effects.