A Comparative Evaluation of Dilution/Attenuation Factors in Risk/Regulatory Settings. T. Sahin, DuPont Environmental Remediation Services, 140 Cypress Station Drive, Houston, TX 77090
Risk-based as well as recently proposed regulatory rules allow use of either generic or derived dilution and attenuation factors (DAFs) in establishing protection (or action) levels in various media. However, use of DAFs in state or federal programs is not consistent and changes drastically from state to state program, from state to federal program, or, sometimes, within a given state program. This paper evaluates how DAFs are used in state and federal risk and compliance rules and suggests alternative approaches to narrow the gap in this field. This comparative evaluation starts with the recently proposed federal hazardous waste identification rule (HWIR) and includes an assessment of DAF use in several states including Texas, California, Michigan, North Carolina, and Connecticut risk rules. DAFs range from 18 to one million in the HWIR to values somewhere in between in state programs.