Overall IRA Objectives. IRAs are short-term actions that are taken to control ongoing risks while site characterization is underway and before a final remedy is implemented. Existing data indicates that property that floods frequently or was flooded during the March 2004 high water event is likely to be contaminated. A number of these properties are actively used for residential, agricultural, and recreational purposes. The primary objectives of this IRA are to identify and mitigate potential human exposure to dioxins and furans that have been or may be found in soils prior to implementation of final response activities. Priority for interim, short-term activities will be given to properties with residential use and soil concentrations that are known or presumed to exceed the Agency for Toxic Substances and Disease Registry (ATSDR) action level of 1,000 parts per trillion toxic equivalent (ppt TEQ). Initially, this will be determined by identifying those properties that flooded in March of 2004. Residential use includes properties with exposure potential that is similar to residential (e.g., schools, child care facilities, nursing homes, adult day care facilities). More specifically, this IRA will: • Identify properties that are subject to flooding by the Tittabawassee River and are, therefore, likely to have elevated concentrations of chemicals of concern. • Establish the priority for mitigating exposure to elevated concentrations of dioxins and furans. • Establish the process by which the need for and range of interim response activities will be determined. This process will consider the potential for human exposure, based on the use of the property and known or potential contaminant concentrations. • Identify a range of interim response activities for specific land uses that can be implemented immediately and are acceptable to the property owner, given property-specific conditions, or presumptively. Priority will be given to identification of properties with residential use that exceed or are presumed to exceed the ATSDR action level of 1,000 ppt. • Implement the mitigation option(s) agreed to by the property owner/occupant [hereafter referred to individually and collectively as “owner”] to limit or prevent exposure to contaminants prior to the implementation of the final remedy. • Implement exposure mitigation measures in response to flood events.
