ABSTRACT
This chapter presents a brief introduction to radiation physics, summarizes how exposure to radioactive elements is measured, and how radiation can affect biological tissue. It provides an overview of the considerable research that has been conducted to quantify environmental exposure of and effects on biota from both naturally occurring and man-made radioactive elements since the 1950s. The chapter reviews a limited selection of studies extracted from current publications and the extensive databases developed by others, to provide an overview of the current understanding of exposure and effects of radionuclides in mammals, birds, terrestrial invertebrates, fish, and aquatic invertebrates. Studies were selected to represent multiple types of responses to ionizing radiation including molecular-level and genetic effects, immune and endocrine responses, reproductive effects, and mortality. Estimated no-effect values for exposure of biota to radionuclides were developed by Environment Canada and Health Canada as part of their effort to assess environmental impacts of releases from nuclear facilities.
