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

$11 Million in Supplemental Funds to Clean up and Redevelop Contaminated Brownfields Sites Across the Country

Posted: August 26, 2014

The U.S. EPA announced $11 million in supplemental funding to help clean up contaminated Brownfields properties. The Revolving Loan Funds (RLF) will help 31 grantees carry out cleanup and redevelopment projects. These projects are expected to create more than 700 jobs and leverage over $57 million in cleanup and redevelopment, while utilizing unique financing mechanisms and partnerships to protect people's health and the environment. Revolving loan funds specifically supply funding for grant recipients to provide loans and sub-grants to carry out cleanup activities at brownfield sites. When these loans are repaid, the loan amount and any interest is then returned to the fund and subgranted or re-loaned to other borrowers, providing an ongoing source of capital for brownfields cleanup. The supplemental grants range in funding from about $200,000 to $500,000 with an average grant award of $350,000.

Environmental Response Television

Posted: July 31, 2014

Environmental Response Television (ERTV) provides video support to EPA's Environmental Response Team (ERT) by providing broadcast-quality documentary video programs on alternative hazardous waste treatment technologies, unique hazardous waste sites, site investigations, and other ERT activities. ERTV's entire catalog of 129 videos is now available for streaming.

Remedial Action Completion Report (CDRL A001B) and Preliminary Closeout Report, Former Air Force Plant PJKS, Waterton Canyon, Colorado

Posted: July 23, 2014

A pilot study conducted at PJKS in 2004-2005 to evaluate the effectiveness of in situ anaerobic reductive dechlorination (ARD) of TCE and NDMA in bedrock source areas showed a decline in TCE contamination, which in 2006 led to the expansion of an interim corrective measure to stimulate ARD in the D-1 area groundwater plume. Horizontal and vertical injection wells delivered sodium lactate, emulsified edible oil (EEO), nutrients, and Dehalococcoides (dhc) to the Fountain Formation aquifer. In 2008, two full-scale biobarriers were constructed via injection of EEO, sodium lactate, and dhc into direct-push boreholes to target the alluvial transition groundwater areas, provide a barrier to plume migration, and further deplete TCE contamination in the downgradient plume. A technical impracticability waiver is recorded in the ROD for NDMA in the crystalline bedrock due to geological and technological limitations, although the VOCs in the bedrock are expected to meet MCLs.

Hexavalent Chromium Removal: Research Project Report to the California Department of Public Health

Posted: July 23, 2014

This report provides technical feasibility and cost data for removing Cr(VI) from drinking water. In spring 2010, the city of Glendale, California, constructed two demonstration facilities consisting of a 425 gpm treatment using weak-base ion exchange (WBA) and a 100 gpm system using reduction/coagulation/filtration (RCF). The WBA resin converts Cr(VI) to Cr(III), retains Cr(III) on the resin, and can achieve levels <1 ppb Cr(VI). The RCF coagulation and filtration processes are similar to conventional water treatment, but ferrous sulfate (rather than ferric iron) is used to reduce Cr(VI) to Cr(III), in the process producing iron floc with which the Cr(III) adsorbs or coprecipitates. The RCF process with granular media filtration can reliably achieve Cr(VI) concentrations <1 ppb and total Cr concentrations <5 ppb; however, due to the multiple treatment process steps, RCF is relatively labor intensive. Both systems achieved the target Cr level of 5 ppb. The RCF was shut down in July 2012, and the WBA continues to operate.

A Multi-Site Survey to Identify the Scale of the 1,4-Dioxane Problem at Contaminated Groundwater Sites

Posted: July 23, 2014

Investigators used intensive data mining to identify and evaluate >2,000 sites in California where groundwater has been affected by chlorinated solvents and/or 1,4-dioxane (dioxane). Dioxane was detected at 194 of the sites, with 95% containing one or more chlorinated solvents. Dioxane frequently co-occurs with 1,1,1-TCA (76% of the study sites); however, no dioxane analyses were conducted at 332 (67%) of the 1,1,1-TCA detection sites. At sites where dioxane has been identified, plumes are dilute but not large (median maximal concentration of 365 µg/L; median plume length of 269 m) and have been delineated to a similar extent as typically co-occurring chlorinated solvents. At sites where dioxane and chlorinated solvents co-occur, dioxane plumes frequently are shorter than the chlorinated solvent plumes (62%). Study results suggest that dioxane has not migrated beyond chlorinated solvent plumes and existing monitoring networks at the majority of sites, and that the primary risk is the large number of sites where dioxane likely is present but has not been identified.

A Risk/Benefit Appraisal for the Application of Nano-Scale Zero Valent Iron (NVZI) for the Remediation of Contaminated Sites

Posted: July 23, 2014

This report discusses the relative risks and benefits of NZVI usage for in situ remediation (i.e., the potential for the NZVI treatment agent itself to present human health or environmental risks) and its sustainability as a technique; identifies the areas where further investigation might be required; and provides an overview of NZVI use in full-scale, pilot, and lab studies to date. This paper is intended to help stakeholders by identifying key issues and providing a basis for evidence-based decisions.

Field Demonstration, Optimization, and Rigorous Validation of Peroxygen-Based ISCO for the Remediation of Contaminated Groundwater: CHP Stabilization Protocol

Posted: August 1, 2014

Although catalyzed hydrogen peroxide propagation (CHP) is the in situ chemical oxidation (ISCO) process with the most robust chemistry and potential for contaminant destruction, H2O2 is unstable in the subsurface and can be difficult to manage effectively. Recent advances, however, show that the addition of sodium citrate, sodium malonate, and sodium phytate potentially can slow H2O2 decomposition rates up to 50-fold. The optimal implementation of these stabilizers for use in ISCO CHP field applications is detailed in this guide and illustrated with two case histories.

Demonstration of An In-Situ Friction-Sound Probe for Mapping Particle Size at Contaminated Sediment Sites

Posted: August 1, 2014

Knowledge of grain size at sediment study sites provides lines of evidence that can be applied to identify potential areas of contaminated sediment and contaminant discharge zones. The effectiveness of the sediment friction-sound probe (SED-FSP) technology was evaluated in the field for direct in situ measurement of grain size at (1) a contaminated sediment site; (2) a thin-layer containment cap over contaminated sediment to demonstrate the technology's vertical profiling capabilities; and (3) a groundwater-surface water interaction site.

In-Situ Remediation Pilot Study Report Area of Concern I (AOC I): Atlantic Fleet Weapons Training Area, Vieques Former Naval Ammunition Support Detachment, Vieques, Puerto Rico

Posted: August 1, 2014

This report summarizes the activities performed and data obtained during the in situ chemical oxidation (ISCO) and enhanced in situ bioremediation (EISB) pilot study conducted at AOC I, the site of a former asphalt plant that operated from the 1960s through 1988. The pilot addressed benzene, bis(2-ethylhexyl)phthalate, 1,2-dichloroethane, 1,2-dichloropropane, 2-methylnapthalene, and naphthalene contamination in the groundwater. The pilot was implemented in a two-step systematic approach—ISCO using injection of sodium persulfate (sodium hydroxide alkaline-activated Klozur) directly followed by EISB (oxygen-releasing compound "socks")—to oxidize organics and then increase the intrinsic biodegradation rate to reduce the attenuation time needed to achieve acceptable contaminant concentrations in groundwater. The baseline monitoring and ISCO injection were initiated in March 2010, followed by a post-injection monitoring event, application of EISB, and then three additional post-injection performance monitoring events, with the last monitoring event completed in November 2012.

Application of Biofilm Covered Activated Carbon Particles as a Microbial Inoculum Delivery System for Enhanced Bioaugmentation of PCBs in Contaminated Sediment: Phase 1 Final Report

Posted: August 1, 2014

Anaerobically dechlorinating biofilms were added to sediment (1) as bacteria localized and concentrated onto activated carbon (AC) surfaces in active biofilm communities or (2) as enriched wastewater sludge biofilms. Both forms of dechlorinating biofilm were applied to mesocosms consisting of PCB-contaminated sediment from Grasse River, New York. The dechlorinating bacteria remained in the sediment throughout the experiment and increased almost 2-fold in numbers. Dechlorination by the biofilm-covered AC particles with DF1 culture was less extensive compared to the enriched sludge biofilm, but application of either system enhanced the dechlorination of PCBs in sediment and thus made the congeners available for subsequent aerobic degradation and removal.

Technical Resource Document On Monitored Natural Recovery

Posted: August 1, 2014

This technical resource document is designed to complement Chapter 4 on monitored natural recovery in EPA's 2005 Contaminated Sediment Remediation Guidance for Hazardous Waste Sites by providing detailed information on field-scale methodologies and approaches that can be used to measure or predict natural processes that contribute to receptor risk reduction at contaminated sediment sites.

Ground Water Issue Paper: Synthesis Report On State of Understanding of Chlorinated Solvent Transformation

Posted: August 1, 2014

This paper summarizes the biotic and abiotic transformations of chlorinated solvents used at industrial and dry-cleaning facilities: PCE, TCE, TCA, and daughter products. It briefly describes the factors that affect the transformation mechanisms as well as the measurements necessary to distinguish among the mechanisms. The paper serves as a guide for developing an advanced groundwater transport model, with governing equations for simulating these processes in models.

Evaluating Potential Exposures to Ecological Receptors Due to Transport of Hydrophobic Organic Contaminants in Subsurface Systems

Posted: August 1, 2014

Detailed discussion of enhanced transport mechanisms is the focus of this technical paper. It recommends several types of screening assessments to evaluate site conditions for the potential to enhance transport of HOCs—PCBs, dioxins, fuels (including the influence of MTBE), and creosote and tar DNAPL—as well as site artifacts that result from inadequate well installation and sampling procedures within a groundwater monitoring network. These assessments are incorporated into a suggested three-tiered decision analysis process that provides a summarized view of the upland contaminant-source characteristics that need evaluation to establish whether facilitated transport of HOCs might occur at a given site.

An Injectable Apatite Permeable Reactive Barrier for in Situ 90Sr Immobilization

Posted: August 20, 2014

An injectable permeable reactive barrier (PRB) technology was developed at DOE's Hanford facility to sequester Sr-90 in groundwater through the in situ formation of calcium-phosphate mineral phases, specifically apatite, which incorporates Sr-90 into the chemical structure. The development approach included bench-scale experiments, an initial pilot-scale field test, and in 2008 the emplacement of a 300-ft PRB at treatability-test scale. The apatite amendment formulation uses two separate precursor solutions, one containing a Ca-citrate complex and the other a Na-phosphate solution, to form apatite precipitate in situ. Citrate is needed to keep calcium in solution long enough to achieve a more uniform and areally extensive distribution of precipitate formation. The 300-ft PRB was installed on the downgradient edge of a Sr-90 plume beneath the Hanford site to reduce Sr-90 flux discharging to the Columbia River. Monitoring data collected to date indicate that the barrier is meeting treatment objectives (i.e., 90% reduction in Sr-90 concentration) and continues to meet remedial objectives more than four years after installation. See additional details in report DOE/RL-2013-22:

Determination of Polychlorinated Biphenyls (Pcbs) in Sediment and Biota

Posted: August 20, 2014

The determination of PCBs in sediment and biota generally involves extraction with organic solvents, cleanup, and gas chromatographic separation with electron capture detection or mass spectrometry. Due to the low concentrations of non-ortho-substituted PCBs compared to those of other PCBs, their determination may require an additional separation step. All stages of the procedure are susceptible to insufficient recovery and/or contamination; therefore, quality control procedures are important to check method performance.