It’s now been 15 years since the publication of Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface by Todd Wiedemeier, Hanadi Rifai, Chuck Newell and John Wilson. Since that time, there have been many advances in characterization, data interpretation and regulatory thinking that have become standard practice in our approach to monitored natural attenuation (MNA). In an effort to summarize these recent advances, ESTCP funded Dr. Dave Adamson and Dr. Chuck Newell from GSI Environmental Inc. to update this guidance in the form of frequently asked questions.

The document Frequently Asked Questions about Monitored Natural Attenuation in Groundwater has recently been posted to the ESTCP website as a printable document. The document leads readers through a series of 28 questions on monitored natural attenuation, grouped into six categories: MNA as an evolving technology; the basis for MNA; new contaminants for the MNA lineup; new techniques and tools; emerging issues for evaluating MNA as a remedy; and implementation and site closure.

                                                                                                                               The document provides a concise overview of current knowledge regarding management of subsurface contaminant releases using MNA. The envisioned audience includes state regulators, federal regulators, industry, consultants, DoD staff, and members of the local community involved in selecting remedies for contaminated sites. The intended value of the document is to provide current knowledge in support of sound decisions. In the interest of brevity, the document was written assuming that the reader has a general understanding of hydrogeology, the movement of chemicals in porous media, remediation technologies, and the remedy selection process.

The USEPA will be hosting an internet seminar on this updated information on monitored natural attenuation via their Contaminated Site Clean-Up Information (CLU-IN) website. Interested participants can register at the CLU-IN site for the internet seminar to be held on June 13, 2014 from 1:30 – 3:00 PM ET.