Case Study: A Large Scale Ecological Risk Assessment. J. A. Margolin and M. T. Sorensen, Law Engineering and Environmental Services, Inc., 114 TownPark Drive, Kennesaw, GA 30144
To fulfill the requirements of the Resource Conservation and Recovery Act (RCRA), an ecological risk assessment (ERA) has been conducted at an ammunition plant located in Kansas. This 10,000 acre facility, which is currently not in operation, produced munitions propellants and related products from 1943 until 1992. Due to production and support operations, a variety of constituents have been released to the environment at the facility. More than 50 Solid Waste Management Units (SWMUs) have been identified at the plant, including explosives production areas, landfills, static rocket test areas, burning grounds, and wastewater lagoons. The constituents of potential concern (COPCs) that were selected for use in the ERA include explosives, inorganics, and polychlorinated biphenyls (PCBs). As part of the ERA, five assessment endpoints representing a range of trophic levels and habitats were selected for evaluation, and multiple measurement endpoints ("measures of effect") were identified with each of the assessment endpoints. The measurement endpoints included ecological effects quotients, population density estimates, body weight measurements, observations of external abnormalities, and comparison to surface water and sediment criteria. Assessment endpoint-specific risks and ecological significance were determined by considering the measurement endpoint risk estimates in conjunction with measurement endpoint-specific uncertainty assessments and weight-of-evidence evaluations. An overview of the ERA conducted for this facility, including development of assessment and measurement endpoints and a comparison of modeled risk estimates with risk estimates based on field observations, will be presented.