Meltwater from snow contaminated by oil sands emissions is toxic to larval fish, but not spring river water

To assess the toxicity of winter-time atmospheric deposition in the oil sands mining area of Northern Alberta, embryo-larval fathead minnow (Pimephales promelas) were exposed to snowmelt samples. Snow was collected in 2011–2014 near ( 25 km) oil sands mining. Snow was shipped frozen back to the laboratory, melted, and amended with essential ions prior to testing. Fertilized fathead minnow eggs were exposed (< 24 h post-fertilization to 7–16 days post-hatch) to a range of 25%–100% snowmelt. Snow samples far from (25–277 km away) surface mining operations and upgrading facilities did not affect larval fathead minnow survival at 100%. Snow samples from sites near surface mining and refining activities (< 7 km) showed reduced larval minnow survival. There was some variability in the potencies of snow year-to-year from 2011 to 2014, and there were increases in deformities in minnows exposed to snow from 1 site on the Steepbank River. Although exposure to snowmelt from sites near oil sands surface mining operations caused effects in larval fish, spring melt water from these same sites in late March–May of 2010, 2013 and 2014 showed no effects on larval survival when tested at 100%. Snow was analyzed for metals, total naphthenic acid concentrations, parent PAHs and alkylated PAHs. Naphthenic acid concentrations in snow were below those known to affect fish larvae. Concentrations of metals in ion-amended snow were below published water quality guideline concentrations. Compared to other sites, the snowmelt samples collected close to mining and upgrading activities had higher concentrations of PAHs and alkylated PAHs associated with airborne deposition of fugitive dusts from mining and coke piles, and in aerosols and particles from stack emissions.

Supplemental Information

1. Joint Canada-Alberta Oil Sands Monitoring (JOSM)

The Governments of Canada and Alberta have committed to implementing scientifically rigorous, comprehensive, integrated and transparent environmental monitoring of the oil sands region to ensure this important national resource is developed in a responsible way. Working together, the implementation of monitoring enhancements will ensure installation of necessary infrastructure and appropriate integration with existing monitoring activities in the region. The efforts contribute to an improved understanding of the long-term cumulative effects of oil sands development.

Since 2012, the governments of Alberta and Canada have worked to implement an environmental monitoring program for the oil sands, which integrates air, water, land, and biodiversity. The intent is to improve the characterization of the state of the environment and enhance understanding of the cumulative effects of oil sands development activities in the oil sands area. To date, the Joint Canada-Alberta Oil Sands Monitoring Program has significantly improved the ability to track low-level contaminants by increasing the geographic coverage of monitoring efforts—nearly doubling the number of sites monitored, increasing the frequency of sampling, sampling for more compounds and with more sensitive detection methods, and integrating results (https://www.canada.ca/en/environment-climate-change/news/2017/12/canada-alberta_oilsandsenvironmentalmonitoring.html).

For more information on the JOSM, please visit https://www.canada.ca/en/environment-climate-change/services/oil-sands-monitoring.html