Analysis of the Isotopic Composition of Molybdenum in Water Samples Along the Athabasca River

The Athabasca bituminous sands, located in the northeastern region of Alberta, are sources of bitumen from which oil and other petroleum products are produced. The extraction of bitumen from the bituminous sands raises concerns that environmentally harmful byproducts may leak into the Athabasca River. The objective of this project was to investigate the concentrations and isotopic compositions of molybdenum in the Athabasca River, which is typically found in elevated amounts in bitumen, relative to the continental crust. ~Water samples were collected along the river upstream and downstream from Fort McMurray and in the vicinity of oil sand operations. Relative isotopic compositions of $^{\mathrm{98}}$Mo:$^{\mathrm{95}}$Mo were measured and reported as delta values. The Mo isotopic compositions ranged between 1.50 - 1.79 per mill along the river. Mo concentrations were found to range between (0.2703 -- 0.7038)*10$^{\mathrm{-6}}$ g Mo/L. These are significant variations in both isotopic composition and concentration and indicate that the sources of Mo change along the Athabasca River. Based on these results, a much more extensive study is underway to identify possible sources of Mo to the river.