The report presents the findings of the September 1970 environmental radiation study conducted in the environs of the Rocky Flats Plutonium Plant (near Golden, Colorado). The field study and subsequent laboratory analyses were conducted by the staff of the Radiological Activities Section, Division of Technical Support, Water Quality Office, Environmental Protection Agency, Cincinnati, Ohio (an organizational unit of the Federal Water Quality Administration at the time of the study; reorganized into EPA in December 1971). Due to personnel transfers and changes in program responsibilities, a report on the study was not completed by the Radiological Activities Section prior to its dissolution from the EPA organizational structure during the first half of 1973. Since the primary investigators are now members of the Technical Investigations Branch, Surveillance and Analysis Division, and the environmental impact of the Rocky Flats Plant is a Region VIII concern, publication is undertaken as a regional responsibility.