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152 | Impact of Radionuclides and NuclearWaste on Nonhumans and Ecosystems Written by Karen Lowrie, based in part on an interview with Joanna Burger, with comments by Keith Florig Background The prairies, wetlands, deserts, and forests within and surrounding some U.S. Department of Energy (DOE) nuclear weapons facilities are contaminated with radioactive materials released from the facility. Often these lands are so far from population centers that they pose little risk to humans. Radiation exposure to the animals and plants that inhabit the land, however, can be of concern under some conditions. When a radioactive substance is released into or present in an environment, it can affect anything in the environment that is a receptor of that substance. Often news stories will focus on effects of radioactive contaminants or nuclear waste remediation activities on the human workers or human populations nearby, or on the damage to natural resources such as soils or groundwater. However, nonhuman living things (organisms), such as other animal species and plants that are within a pathway of exposure, can also be impacted. An exposure could occur, for example, when the animal ingests, absorbs, or breathes a radionuclide, or when a plant draws a contaminant out of the soil. The effect varies in accordance with the dose, period of exposure, and vulnerability of individual organisms. For almost all contaminants , some organisms are more susceptible than others. It is important to consider ecological impacts, because ecological resources are very important and prominent at many of the large DOE nuclear weapons sites. The DOE left buffer lands around the production and research facilities at its sites, and many sites were placed in remote locations in the first place because of the need for secrecy and the need to place them away from human populations. Approximately 79% of DOE land is in buffer areas, providing habitat and intact ecosystems, some in areas especially protected for research, preservation, or recreational uses. Thus, the untouched areas in the buffer lands are actually in better shape ecologically than the surrounding areas that have been cleared for agriculture, factories, or houses. And further, since the Impact on Nonhumans and Ecosystems | 153 DOE left the land alone for more than 50 years, it actually recovered more than the surrounding lands and, in some instances, has the only undisturbed biomes in the region (that is, habitats unique to that region, such as pine barrens or shrub-steppe). The DOE’s mission includes environmental restoration, and DOE’s stewardship program includes ecosystem management and integration of economic, ecological, social, and cultural factors in land use decisions (DOE Order 430.1). Before the initiation of land-disturbing or building and structure modifications at the site, archeologists conduct cultural resource surveys or historical evaluations to identify important cultural and historical resources, evaluate the cultural and historical significance, and assess impacts. Native American representatives also conduct cultural assessments of proposed land disturbances to identify resources that may be of religious or cultural significance to American Indians. (For example, see DOE, 2002, for the Yucca Mountain final environmental impact statement [FEIS].) Ecological risk assessment has been developed to evaluate current or potential damage to ecosystems and their biota (species, populations, and ecological processes). The desired endpoints are ecosystem health, integrity and sustainability, and survival of rare species. To determine risks to ecosystems, scientists use a five-step process. First, they characterize the ecosystem in terms of its components and its functions. Second, they characterize the environmental contaminants for their constituents, toxicity, and form. Third, they assess the exposure (dose or potential dose) to an organism, relative to its body weight. Fourth, because it is impossible to monitor every species, they identify indicator species at different levels in the system (producer, consumer, and decomposer) and biomarkers (substances in body tissue or fluids) that indicate exposure, effect, and susceptibility. For example, a top-level carnivore could be selected as a bioindicator of ecosystem health and a biomarker could be an enzyme that is collected from blood or urine. Fifth, ecological risk assessors need to conduct biomonitoring and surveillance to measure the numbers of organisms, mortality rates, reproductive rates, and biomarkers. Surveillance can also include field observations of behavior or food-web relationships. If monitoring data is reported, to have confidence in the data, it is important to see that QA/QC procedures were followed. Identifying the Issues Some of the concerns related to the impact of nuclear materials on nonhumans include exposures to top-level predators through ingestion or through [3.143.9...

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