Other Recent Additions
Recent Additions
3rd Western Symposium Design and Construction Issues at Hazardous Waste Sites, Denver, CO, November 5-7, 2018
Posted: May 16, 2018
The past success of the conferences have been directly related to excellent presentations with interesting topics and top-notch professionals. We encourage you to submit an abstract this year on a successful project or thought-provoking topics. Abstracts are due on June 15, 2018.
Online Listening Session on Expediting Negotiations with PRPs for Superfund Cleanup Agreements, Sponsored by US EPA Office of Site Remediation Enforcement/OECA, Mon, May 21, 2018 from 12:00 PM - 2:00 PM EDT
Posted: May 10, 2018
The U.S. Environmental Protection Agency's (EPA) Office of Enforcement and Compliance Assurance (OECA) is hosting a listening session to receive public remarks on Recommendation 16.2 of the Superfund Task Force Report. This listening session is one of a series the Agency is hosting to provide a forum for EPA personnel to take input from stakeholders regarding specific Superfund Task Force recommendations in an effort to increase public participation and transparency, and strengthen communication with stakeholders.
Bay Road Holdings, East Palo Alto (Formerly Romic)
Posted: March 23, 2018
Bay Road Holdings LLC (formerly Romic Environmental Technologies Corp.) is a closed hazardous waste management facility located in East Palo Alto, Calif., near the San Francisco Bay. The facility ceased operations in 2007, and all surface structures were demolished in 2009. Historical facility operations from 1964 to 2007 included solvent recycling, fuel blending, wastewater treatment, and hazardous waste storage and treatment, resulting in releases that contaminated the soil and groundwater beneath the site. Biological treatment was the primary remedy selected by EPA to address the solvent-contaminated soil and groundwater. The biological treatment approach introduces a substrate (cheese whey and molasses were used in early testing) through horizontal injection wells (>200 ft long) for distribution via an in situ delivery (ISD™) groundwater recirculation system. The horizontal injection wells and the biological treatment system can operate independently and thus not interfere with the redevelopment ongoing at the surface. See details of this system in the ISD™ Groundwater Recirculation Pilot System Installation Work Plan at
Estimating the High-Arsenic Domestic-Well Population in the Conterminous United States
Posted: March 23, 2018
A logistic regression model of the probability of having arsenic >10 µg/L (high arsenic) in wells at the county, state, and national scales was developed using As concentrations from 20,450 U.S. domestic wells. The population in the conterminous U.S. using water from domestic wells with predicted As concentration >10 µg/L is 2.1 million people (95% CI is 1.5 to 2.9 million). Although some parts of the U.S. were underrepresented with As data, predictive variables available in national data sets were used to estimate high As in unsampled areas. By predicting to all of the conterminous U.S., the investigators were able to identify areas of high and low potential exposure in areas of limited As data, which can be viewed as potential areas to investigate further or to compare to more detailed local information. This paper is Open Access at
Rapid Assessment of Remedial Effectiveness and Rebound in Fractured Bedrock: ESTCP Cost and Performance Report
Posted: April 4, 2018
A demonstration of the rapid assessment protocol was performed in shallow bedrock at Calf Pasture Point in Rhode Island, where TCE was the primary groundwater contaminant. While nearly 99% of the TCE was removed from the conductive fracture zone during initial flushing, substantial contaminant rebound (up to ~5% of TCE baseline concentration) was observed over the 5-month rebound period. The rate and extent of observed contaminant rebound was reasonably described using a matrix back-diffusion model and CSIA, both serving as lines of evidence that the observed rebound was due to matrix back-diffusion. The back-diffusion model further predicted that over a decade of treatment likely would be needed to reduce TCE concentrations by 99% in the conductive fractures. CSIA testing not only served as a line of evidence demonstrating that the rock matrix was the source of the observed rebound but also confirmed the occurrence of abiotic dechlorination of TCE and DCE within the rock matrix.
Historical Releases of Mercury to Air, Land, and Water From Coal Combustion
Posted: April 4, 2018
Coal combustion is one of the largest contemporary sources of anthropogenic mercury (Hg). It releases geologically sequestered Hg to the atmosphere, and fly ash can contaminate terrestrial and aquatic systems. Coal combustion released an estimated cumulative total of 38.0 (14.8-98.9, 80% C.I.) Gg (gigagrams, 109 g or a thousand tonnes) of Hg to air, land, and water up to the year 2010, most of which (97%) occurred after 1850. The rate of release has grown by two orders of magnitude, from 0.01 Gg/yr in 1850 to 1 Gg/yr in 2010. Geographically, Asia and Europe each account for 32% of cumulative Hg releases and an additional 18% is from North America. About 26.3 (10.2-68.3) Gg or 71% of the total was emitted directly to the atmosphere, mostly from the industrial (45%) and power generation (36%) sectors, while the remainder was disposed of to land and water bodies. While Europe and North America were the major contributing regions until 1950, Asia has surpassed both in recent decades. By 2010, Asia was responsible for 69% of the total releases of Hg from coal combustion to the environment. Control technologies installed on major emitting sources capture mainly particulate and divalent Hg; hence, the fraction of elemental Hg in emissions from coal combustion has increased over time from 0.46 in 1850 to 0.61 in 2010. About 11.8 Gg of Hg or 31% of the total has been transferred to land and water bodies through disposal or utilization of Hg-containing combustion waste and collected fly ash/flue-gas desulfurization sludge; ~8.8 Gg of this Hg has simply been discarded to waste piles or ash ponds or rivers.
Developing Sediment Remediation Goals at Superfund Sites Based On Pore Water for the Protection of Benthic Organisms From Direct Toxicity to Nonionic Organic Contaminants
Posted: April 4, 2018
This document contains a methodology for developing and applying pore water remediation goals (RGs) for nonionic organic contaminants in sediments for the protection of benthic organisms. The text provides a technical approach and basis for setting the pore water RGs for contaminants in sediments. Contaminant concentrations in the sediment pore water measured using passive sampling directly incorporate bioavailability of the chemicals at the site into the development of site-specific sediment RGs. Also discussed is how to evaluate the consistency between passive sampling measurements and sediment toxicity testing results. When these data are consistent, there is reasonable assurance that the causes of toxicity to benthic organisms in the sediment have been correctly identified and that the developed pore water RGs for the contaminants will be protective of the site's benthic organisms.
Manufactured Gas Plant Remediation: a Case Study
Posted: April 4, 2018
The assessment, remediation, and redevelopment of manufactured gas plant (MGP) sites pose a significant technical and financial challenge to successor property owners, including municipalities and other public entities undertaking brownfields revitalization, and to their consulting environmental engineers. Due to the toxicity of many coal tar constituents, sites contaminated as a result of gasworks operations pose a significant threat to public health. The history of the manufactured gas industry in Massachusetts (the largest in the United States) is discussed, as well as the toxicity of gasworks waste products. The book then addresses the technical challenges in the MGP cleanup process, from site assessment, to remediation, to redevelopment. See a brief PDF preview of the book at
Status Report On Remedy Effectiveness: Hookston Station, Pleasant Hill, California
Posted: April 18, 2018
As detailed in this report, the Hookston Station parties have implemented several remedial actions to address environmental impacts associated with the presence of TCE and daughter products. Between 2008 and 2010, five in situ chemical oxidation injection events were implemented to remediate B-Zone groundwater. Performance monitoring showed successful distribution of potassium permanganate throughout the targeted treatment area. VOC concentrations in B-Zone wells within the core of the on-site source area are lower than pre-remediation results by up to two orders of magnitude. No additional ISCO injection events are needed. Since the installation in 2009 of a permeable reactive barrier (PRB) containing zero-valent iron to remediate A-Zone groundwater, TCE concentrations in groundwater have decreased significantly. Owing to the PRB's efficacy, only a handful of wells remain above the cleanup standards, and CVOC concentration trends in soil vapor are decreasing.
River Raisin Area of Concern: NAPL Area Remediation
Posted: April 18, 2018
The NAPL Area is defined as the portion of the River Raisin AOC that contains an apparent NAPL substance and concentrations of PCBs >50 ppm. Remediation activities performed in 2016-2017 within the NAPL Area consisted of dredging sediment containing PCBs to specified depths, followed by placement of cover material in the nearshore area or an engineered cap in other dredged areas. To sequester PCBs remaining in deeper subgrade materials in the NAPL Area, two types of multi-layered engineered caps (A and B) were placed on the post-dredge surface within the navigation channel and transition areas. The difference between Cap A and Cap B was the size of armor stone needed to protect the chemical containment layer. The cap profile consisted of a chemical layer (sand/organoclay mixture) to contain potential PCB transport from underlying materials, overlain by a gravel filter layer, and followed by the armor stone layer. The single chemical containment layer, 12 in deep, comprised 3% minimum organoclay mixed with sand. Decontamination and demobilization of materials and equipment commenced upon completion of dredging and capping.
Occurrence and Behavior of Per- and Polyfluoroalkyl Substances From Aqueous Film-Forming Foam in Groundwater Systems
Posted: April 18, 2018
Background is presented on aqueous film-forming foam and per- and polyfluoroalkyl substances (PFAS) source characteristics in Part 1 of this paper, including common industrial and consumer PFAS sources. Part 2 discusses chemical properties, sorption and retention parameters, observed transformation properties of PFAS and related compounds, and knowledge gaps. This paper is Open Access at
Evaluating PFAS Cross Contamination Issues
Posted: April 18, 2018
Due to the ubiquitous nature of per- and polyfluoroalkyl substances (PFASs) in commonly used sampling materials and personal protective equipment, mitigating the risk of cross contamination can be challenging when planning and executing a PFAS sampling program. This paper describes a conservative approach to PFAS sampling and includes an evaluation of three insect repellent products to determine their suitability for use during PFAS investigation. This paper is Open Access at
Technology Review and Evaluation of Different Chemical Oxidation Conditions On Treatability of PFAS
Posted: April 18, 2018
An overview of relevant literature summarizes the use of single or combined reagent chemical oxidation processes that offer insight into oxidation-reduction chemistries potentially capable of PFAS degradation. Based on the literature review, bench-scale treatability tests were designed and performed to establish optimal conditions for the formation of specific free radical species, including superoxide and sulfate radicals, using varied combinations of oxidants, catalysts, pH buffers, and heat to assess PFAS treatment by chemical oxidants. This paper is Open Access at
Integrating Total Oxidizable Precursor Assay Data to Evaluate Fate and Transport of PFASs
Posted: April 18, 2018
Current commercial laboratory methodologies primarily quantify between 14 and 31 per- and polyfluoroalkyl substances. As an alternative, a total oxidizable precursor assay (TOPA) was developed to quantify measurable concentrations of perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) after aggressive oxidation to convert perfluoroalkyl acid (PFAA) precursors abiotically into PFCAs. This paper discusses the potential application of this approach to characterize PFAS contamination. This paper is Open Access at
In-Situ Remediation of Arsenic-Contaminated Sites
Posted: April 18, 2018
This text provides scientific background, case studies, and future perspectives of in situ arsenic remediation technologies for soils and groundwater at geogenic and anthropogenic As-contaminated sites. Natural arsenic (arsenate and arsenite) as well as organic arsenic compounds are discussed. Technologies covered include geochemical, microbiological, and plant-based ecological solutions for arsenic remediation. View the table of contents at
Extending the Applicability of Compound-Specific Isotope Analysis to Low Concentrations of 1,4-Dioxane
Posted: May 22, 2018
The project objective was to develop a reliable method to perform compound-specific isotope analysis (CSIA) on low aqueous concentrations (1 µg/L) of 1,4-dioxane in groundwater and then apply it to investigate 1,4-dioxane biodegradation. Researchers determined that 0.5 grams of a synthetic carbonaceous sorbent, when added to a 40 mL vial containing aqueous 1,4-dioxane in the 10 to 100 µg/L range, could adsorb > 99% of the 1,4-dioxane from solution. The 1,4-dioxane was recovered from the dried solid sorbent by thermal desorption into a gas chromatograph with isotope ratio mass spectrometry. The method was applied successfully to samples at concentrations in the 1 µg/L range. It is anticipated that the CSIA method will be applied to demonstrate the biodegradation of 1,4-dioxane in the 1-100 µg/L range.
