We show that the oil sands industry releases the 13 elements
considered priority pollutants (PPE) under the US Environmental
Protection Agency’s Clean Water Act, via air and water, to the
Athabasca River and its watershed. In the 2008 snowpack, all
PPE except selenium were greater near oil sands developments
than at more remote sites. Bitumen upgraders and local oil sands
development were sources of airborne emissions. Concentrations
of mercury, nickel, and thallium in winter and all 13 PPE in summer
were greater in tributaries with watersheds more disturbed by
development than in less disturbed watersheds. In the Athabasca
River during summer, concentrations of all PPE were greater near
developed areas than upstream of development. At sites downstream
of development and within the Athabasca Delta, concentrations
of all PPE except beryllium and selenium remained greater
than upstream of development. Concentrations of some PPE at
one location in Lake Athabasca near Fort Chipewyan were also
greater than concentration in the Athabasca River upstream of
development. Canada’s or Alberta’s guidelines for the protection
of aquatic life were exceeded for seven PPE—cadmium, copper,
lead, mercury, nickel, silver, and zinc—in melted snow and/or water
collected near or downstream of development