In John Irving's novel "The Fourth Hand," Dr. Zajac expresses an outdated view regarding the pollution affecting the Charles River. He suggests that while dog waste is a problem, it's relatively minor compared to the more significant contaminants that are discharged into the river regularly. This perspective highlights a broader issue of environmental neglect and the challenges faced in addressing pollution.

Dr. Zajac's comments reveal a certain degree of cynicism about public concerns over pollution. His comparison underscores the severity of the pollution issue and invites readers to consider what constitutes serious environmental harm. Ultimately, the text invites reflection on the differing perspectives on ecological responsibility and the historical context of pollution in urban settings like the Charles River.