This 25-y study monitored aquatic and terrestrial gamma-ray emitting radionuclide concentrations near a nuclear power plant. It is the only known, long term, independently verified, environmental survey of its kind. Sensitive, environmental, bioaccumulating entities included periphyton, flocculated sediment, lichens, and litterfall-humus. They were used to biomonitor the Susquehanna River and surrounding land areas near the PPL Susquehanna nuclear power plant. Sampling began in 1979, before the first plant start-up, and continued for the next 24 y. Approximately 300 monthly data sets cover this time period. Monitoring began 2 mo after the Three Mile Island accident of 28 March 1979, and includes a river monitoring station below Three Mile Island. Ongoing measurements also detected fallout from Chernobyl in 1986. Results indicate that periphyton is the best overall biomonitor. Particular radionuclides exhibit preferential sorption in different biomonitors. Lichens and litter-humus are essentially equivalent radionuclide detectors on land. Although rarely a PPL power plant release, (131)I is a river contaminant. (131)I concentrations are not found uniformly along the entire river, but rather higher concentrations are localized near urban areas. Data indicate that PPL Susquehanna's radionuclide releases have had no known negative environmental or human health impact. This entire study can serve as a useful background radiological database.