I see that my earlier guess was incorrect now that I understand the context. PCA in that context means Pleistocene channel aquifer, which is an aquifer that runs through the eastern side of the oil sands area and up through many of the proposed mining operations. The quality varies from almost potable level to very poor quality. It is similar to a deeper aquifer called the basal aquifer.
In relation to the study you're quoting, I believe at the hearing surrounding the environmental impact assessment there was talk about potential influence of seepage into that Pleistocene channel. In terms of follow-up actions, I do remember the recommendation that there be additional monitoring of that aquifer, and I believe Shell does have required groundwater wells in that aquifer, as do many of the other operators.