Ecological Exposure Research
Human exposure research includes studies on the distribution of humans, the distribution of a number of stressors (physical, chemical and biological) and the overlap between them. Ecological exposure research tends to include more than studies where organisms are substituted for humans and their overlap with stressor distributions are studied. Ecological exposure research can more fully be defined as the development and application of methods to integrate biological data with environmental data to characterize the extent and magnitude of contact between the primary stressor and the initial ecological receptor or receptors:
- Variations in space for a population of a species or a community of different species comes into play
- "Cascades" of effects may occur (exposures and adverse effects to some organisms may translate to exposures of additional organisms).
A Conceptual Framework for U.S. EPA's National Exposure Research Laboratory further delineates differences between human and ecological exposure research:
- "The human receptor is essentially the same in all locations; only stressor intensity, population characteristics (e.g., density), and susceptibility will vary in space. For ecological exposures, location determines not only the stressors present and their intensities, but also which receptors might be present, and the circumstances under which they encounter the stressor. That is, the organisms that are present vary as a function of location, as well."
- "There are many commonalities between human and ecological exposure science and these commonalities serve as the basis for this framework document. There are also differences that must be recognized in order to have a complete understanding of the science. For example, our understanding of the concepts of human and ecological exposure science is influenced by the EPA’s responsibilities in the two areas. The EPA is responsible for human health outcomes solely related to environmental stressors (primarily chemical or biological agents). In contrast, the Agency is responsible for protecting the condition or state of entire ecosystems from multiple stressors, including physical, chemical, and biological agents. Important differences between the human health and ecological disciplines are shown in the table below."