From 1944-1971, the Hanford Reach of the Colombia River in Washington State received quantities of radioisotopes, heat and chemicals from up to 8 plutonium reactors. Subsequently, from 1971-1984 the same part of the river provided cooling water for 3 power-production facilities.Environmental concerns promoted a series of continuing studies to examine various potential adverse effects. No significant impairment of the rivers ecosystem was detected.This book reviews these studies and places them in a historical framework.It provides a unique overview of studies made over a 40-year period which are now scattered through various published and unpublished documents.It should be of interest to all those concerned with aquatic ecology and environmental concerns.