U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Recent Additions

Consideration of Greener Cleanup Activities in the Superfund Cleanup Process

Posted: August 18, 2016

EPA recently issued a guidance memorandum recommending approaches for regional Superfund programs to consider when evaluating greener cleanup activities through the CERCLA process. The memorandum also encourages regions to consider conducting an environmental footprint analysis to help identify best practices that may help minimize the footprint on a site-specific basis. Relevant parts of the CERCLA process include site characterization; remedial investigation and feasibility study or engineering evaluation/cost analysis; development of decision documents; and enforcement mechanisms. The memorandum supplements the Agency's fact sheets and policy statements addressing greener cleanup activities, tools and considerations and is intended as guidance for Fund-lead, federal facility-lead, and potentially responsible party-lead cleanups.

Design and Construction Issues at Hazardous Waste Sites - West, October 25-26 in Denver, CO

Posted: August 5, 2016

Based on the resounding success of the Design and Construction Conference (DCHWS) that has been held over the past 10 years in Philadelphia, the Society of American Military Engineers Denver Post have agreed to "pilot" a DCHWS West delivery in Denver in October of 2016. Potential topics include: design and construction issues and challenges associated with addressing hardrock mining sites; cleanup approaches and challenges associated with remediating large watersheds with contaminated sediments and/or surface water; remediation experiences and challenges associated with addressing hazardous waste contamination in residential/high traffic environments; and experiences and challenges executing adaptive site management strategies at hazardous waste sites in the western United States. Abstracts are due August 26.

Developing Leaching Test Methods for Semi- and Non-Volatile Organic Compounds

Posted: August 2, 2016

This report documents a USEPA workshop in September 2015 in Arlington, VA, and included subject-matter experts from academia. The workshop purpose was to exchange information concerning how to evaluate or predict the potential for leaching of semi- or non-volatile organic constituents at contaminated sites where in place treatment has been used to control migration, and from waste that is disposed or re-used. Workshop discussions focused on identifying technical issues for further consideration to support the development of tools that may be used in making determinations of protectiveness and regulatory compliance.

Extent and Persistence of Secondary Water Quality Impacts After Enhanced Reductive Bioremediation

Posted: July 20, 2016

Although electron donor addition can be very effective in stimulating enhanced reductive bioremediation (ERB) of a wide variety of groundwater contaminants, ERB can result in secondary water quality impacts (SWQI), such as decreased levels of dissolved oxygen, nitrate, and sulfate, and elevated levels of dissolved Mn, dissolved Fe, methane, organic carbon, and naturally occurring hazardous compounds (e.g., As). This report summarizes available information on processes that control the production and natural attenuation of SWQI parameters and can be used as a guide in understanding the magnitude, areal extent, and duration of SWQI in ERB treatment zones, and the natural attenuation of SWQI parameters as the dissolved solutes migrate downgradient with ambient groundwater flow. Information compiled from a variety of sources, including a survey and statistical analysis of SWQI from 47 ERB sites, was integrated to provide a general conceptual model of the major processes controlling SWQI production and attenuation.

A Quantitative Decision Framework for Assessing Navy Vapor Intrusion Sites

Posted: July 20, 2016

In developing a quantitative decision framework to improve decision-making and site management practices for Navy industrial vapor intrusion (VI) sites, a multidimensional database was developed and populated with Navy Environmental Restoration Program VI site data from a diverse range of geologic, geographic, building types, and other site conditions. The decision framework then designed was based on statistical and nonstatistical analyses of both analytical and nonanalytical data in the database. The project focused on chlorinated hydrocarbon sources, which represents the largest potential Navy VI source.

Impacts On Groundwater Quality Following the Application of Isco: Understanding the Cause of and Designing Mitigation for Metals Mobilization

Posted: July 20, 2016

Project objectives were to (1) develop a fundamental and predictive understanding of metals release as a result of three common ISCO treatments; (2) develop a mechanistic geochemical model to describe release and to design mitigation measures; (3) experimentally evaluate the fate of redox and pH perturbations and elevated metals released; (4) demonstrate efficacy of pre-, co-, or post-treatment metals mitigation measures; and (5) develop guidance for the design community to predict release, understand mechanisms, and design mitigation strategies to maximize the utility of ISCO and minimize life-cycle costs.

Bioremediation of Source Zone and Migrated Plumes

Posted: August 22, 2016

The former Unocal distribution facility in Wichita, Kansas, blended and packaged bulk chemicals for industrial customers. During historical operations, PCE was released to the site groundwater. Remedial technologies implemented at the site since 1989 to treat chlorinated VOCs in the groundwater include soil vapor extraction, pump and treat, excavation, bioremediation, and phytoremediation. Despite these measures, contaminated groundwater has migrated a quarter mile from the primary source area to adjacent properties. During annual groundwater monitoring conducted in 2013, PCE and its daughter products were present at concentrations over 10,000 µg/L. Monitoring data indicated that reductive dechlorination was ongoing, but little to no biodegradation was apparent in many off-site portions of the plume. A phased treatment approach is being implemented at the site. Based on results from a 2013 Bio-Trap® treatability study, EHC® and EHC® Liquid were selected to stimulate both biodegradation and chemical reduction. Baseline monitoring was conducted in June 2014, and the first round of injections began in July 2014. A total of ~29,500 lb EHC (as 30% slurry) and 1,850 gal EHC Liquid (diluted to make a 5% solution) were injected among six barriers and one injection grid through 165 injection points over a one-month period. Performance monitoring results (Nov 2014 and Mar 2015) indicate the amendments are conditioning the aquifer to promote reductive dechlorination. Additional information: Interim Measure Injection Completion Report, Former Unocal Chemical Distribution Facility (2015) at

Impact of Clay-DNAPL Interactions On Transport and Storage of Chlorinated Solvents in Low Permeability Zones

Posted: August 22, 2016

The objective of this research was to examine clay-DNAPL waste interactions as a contributor to the accumulation of chlorinated compound contamination in subsurface clay lenses and layers. Results showed that contact between DNAPL waste and Na-smectitic clay materials caused a contraction of the clay's basal space, producing cracking, in a time frame on the order of weeks. The hypothesized mechanism is syneresis, involving the sorption of the surfactants from the waste onto the clay surface and the solvation of the surfactants' aggregates. Numerical simulations suggest that even a small amount of cracking, and the time-variable dissolution of the DNAPL stored in the cracks into the surrounding clay matrix, extends the remediation time by decades.

Integrated Field-Scale, Lab-Scale, and Modeling Studies for Improving Our Ability to Assess the Groundwater to Indoor Air Pathway at Chlorinated Solvent-Impacted Groundwater Sites

Posted: August 22, 2016

This project was conducted primarily at a house overlying a dilute chlorinated hydrocarbon (TCE) groundwater plume. The house was outfitted with sensors and automated systems to facilitate monitoring of indoor air and ambient and building conditions as well as groundwater and soil gas. Monitoring was conducted under both natural and controlled building conditions, and both TCE and radon were quantified in indoor air and soil gas. Sampling was conducted under natural conditions for about 2.5 yr. Two recurring behaviors were observed with the indoor air data. The temporal behavior prevalent in fall, winter, and spring involved time-varying impacts intermixed with sporadic periods of inactivity. In summer, VI had long periods of inactivity combined with sporadic VI impacts. Subsurface concentrations were less temporally variable than indoor air, and the variability increased in moving from the source to indoor air.

Exceptionally Long MTBE Plumes of the Past Have Greatly Diminished

Posted: August 22, 2016

Studies published in the late 1990s and early 2000s identified the presence of exceptionally long MTBE plumes (>2,000 ft) in groundwater, cited in technical literature as characteristic of MTBE plumes. To investigate the subsequent behavior and fate of these MTBE plumes over the past decade, reviewers compiled recent groundwater monitoring records for nine historical MTBE groundwater plumes whose lengths formerly ranged from 2,700 ft to 10,500 ft in length. Groundwater monitoring data compiled in this review show that these large MTBE plumes decreased in length over the past decade, with five of the nine plumes exhibiting decreases of 75% or more compared to their historical maximum lengths. MTBE concentrations within these plumes declined by 93-100%, with two of the nine sites showing such significant decreases (98% and 99%) that the regulatory authority found the sites require no further action. This paper is Open Access at

Integrating Passive Sampling Methods Into Management of Contaminated Sediment Sites: a Guide for Department of Defense Remedial Project Managers

Posted: August 22, 2016

This document discusses how to integrate passive sampling methods into the management of contaminated sediment sites, with a focus on the passive sampling devices most commonly used to measure non-polar organic chemicals, such as PCBs and PAHs.