Sampling of selected wells from Quaternary drift aquifers, Quaternary-Tertiary buried channel aquifers and Lower Cretaceous aquifers, in the Athabasca Oil Sands (in situ) Area, was conducted between the summer of 1999 and the spring of 2001. The purpose of the sampling program was to obtain high-quality water samples that could be used to better define baseline groundwater chemistry in these various geological units.