Since 1998, The Contaminated Site Clean-Up Information (CLU-IN) website has presented Internet Seminars covering a wide variety of technical topics related to hazardous waste characterization, monitoring, and remediation. For select seminar topics offered since 2012, we are making complete video recordings available through our archives. This feed contains all video seminars archived in the last 12 months. For a complete list of seminars archived since 2000, please visit http://www.clu-in.org/live/archive/. Our Rehabilitation Act Notice for reasonable accommodation is available at http://www.clu-in.org/training/accommodation.cfm. CLU-IN was developed by the U.S. Environmental Protection Agency (EPA) but is intended as a forum for all waste remediation stakeholders. For more information and to view upcoming live offerings, please visit http://www.clu-in.org/live/. For a complete list of RSS feeds available on CLU-IN, please visit http://www.clu-in.org/rss/about/.
http://www.clu-in.org/live/archive
Recommended Updates to the Soil-to-Groundwater Pathway in the U.S. EPA's 1996 Soil Screening Guidance (Jul 20, 2023)
As part of a Virtual Student Federal Service internship project, this presentation provides an overview of the history, current use, and recommended improvements of the dilution attenuation factor (DAF) used when calculating soil screening levels (SSL), along with recommendations to address the assumption of an infinite contaminant source when calculating SSLs. This project focuses on the United States Environmental Protection Agency's (U.S. EPA) 1996 Soil Screening Guidance (SSG), which provides guidance for calculating SSLs as implemented in the Regional Screening Level (RSL) and Preliminary Remediation Goal (PRG) calculators. The U.S. EPA's SSG currently utilizes a single default nationwide DAF during the calculation of SSLs when a risk of soil-to-groundwater contaminant migration is present, which may not reflect the significant hydrologic differences across the U.S. Additionally, the SSG's calculation assumes an infinite source of contaminant is present, which may not be an accurate reflection of the conditions at sites. This project examines the history and initial development of the DAF, reviews potential issues with the current use of the DAF, and provides recommendations for improvement to the DAF calculations, including hydrologic region-specific DAFs, and a calculator to correct the infinite source assumption inherent in SSL calculations. The presentation concludes with the limitations of this analysis and recommendations for future work to improve the DAF and SSG. To view this archive online or download the slides associated with this seminar, please visit http://www.clu-in.org/conf/tio/Soil-to-Groundwater-Pathway_072023/