This issue highlights projects involving optimization reviews undertaken by the U.S. EPA and partnering state agencies or site owners. Each project involved an optimization review performed by an independent organization and funded by EPA's Office of Superfund Remediation and Technology Innovation. The highlighted projects illustrate how optimization can be used to modify specific components of a treatment process or monitoring program in order to improve remedy effectiveness, reduce remedy implementation costs, and increase technical efficiencies. The highlighted projects focus on sites with operating remedies; however, EPA is now applying optimization to all phases of remediation, from remedial investigation to site completion.

The U.S. Small Business Administration (SBA) and the Department of the Navy have launched a new website focused on providing small businesses with access to Green Government Opportunities. Green Government Opportunities is an SBA website that serves as a one-stop destination for all things green in small business. Its purpose is to provide a resource through which small businesses can gain access to green contracts, grants, and partnerships with the Navy. Its primary feature is a consolidated search capability that allows small businesses to filter procurement opportunities using keywords important to them. The site promotes sustainable environmental procurement practices and allows for the sharing of relevant green small business information and third-party tools that facilitate green procurement.

This project demonstrated and validated use of the GTS groundwater optimization software, developed by MacStat Consulting and Science Applications International Corporation (SAIC), at three DoD and DOE sites: Air Force Plant 44, the former Nebraska Ordnance Plant, and DOE's Fernald facility. The GTS software was found to be easy to use and navigate by the testers and mid-level site analysts, even though none of these users had been formally trained on the software.

An archived video of a short course presented in December 2011 at the SERDP and ESTCP Symposium highlights the potential of thermal treatment technologies. The on-demand short course summarizes in four modules the results from several recent research and demonstration projects focused on improving the technology and understanding its performance, especially for difficult sites, such as those with DNAPL contamination in fractured bedrock. The course covers the state of the art and recent advances in the fundamental understanding of various thermal technologies: electrical resistance heating, conductive heating/in situ thermal desorption, steam-enhanced extraction, radio frequency heating, and large-diameter auger soil mixing combined with steam/hot air injection. The course also addresses a combined remedy approach, i.e., following thermal treatment with enhanced bioremediation to remove residual contamination. Four course modules are available on the SERDP-ESTCP website:

Mass discharge and flux measurements are being used more frequently to characterize and monitor groundwater contamination. Their use is increasing as a result of several recent improvements in mass flux and discharge measurement methods, as well as a growing recognition that mass flux data can improve conceptual site models and remediation decisions as compared to a reliance on concentration data alone. Mass discharge and mass flux estimates are useful for managing groundwater contamination because they quantify the source or plume strength at a given time and location. These estimates can be particularly useful in addressing complex and difficult sites. The on-demand video of a short course presented in December 2010 covers how mass information can improve contaminated site management. The course is based on the technology overview document, Use and Measurement of Mass Flux and Mass Discharge, published in 2010 by the Interstate Technology & Regulatory Council. The presenters describe available measurement and estimation techniques and examine several case studies of mass flux measurements at contaminated sites. The course has six modules:

The purpose of this paper is to discuss the methods used to develop inhalation cancer risk estimates associated with emissions of chromium and nickel compounds from coal- and oil-fired electric utility steam-generating units (EGUs) in support of EPA's Mercury and Air Toxics Standard (MATS). The derivation of cancer risk estimates is based on the speciation data available from selected source types and on the available unit risk estimates reflecting the dose that corresponds to a specific level of cancer risk. This document includes discussions for both emissions of chromium (Section 2) and nickel (Section 3) compounds with regard to (1) the methods and rationale used in previous analyses (where applicable), (2) the methods used in the recent analysis for MATS (considering previous methods and currently available data), and (3) a discussion of the uncertainties and/or limitations of the methods used. In this document, the authors consider the emissions of chromium compounds from both coal- and oil-fired EGUs and the emissions of nickel compounds from oil-fired EGUs as these emissions are major contributors to inhalation cancer risk estimates from each these source types. www.epa.gov/ttn/atw/utility/ni_cr_methods_final_report_cover.pdf

A variety of sorbent materials have demonstrated the potential to immobilize heavy metals, but the complexity of multi-element contamination makes choosing the appropriate sorbent mixture and application dosage highly challenging. This paper outlines a strategic framework designed to address the development of an in situ sediment remediation solution systematically through assessment, feasibility, and performance studies. The decision-making tools and the experimental procedures needed to identify optimum sorbent mixtures are detailed, with particular emphasis on the utilization and combination of commercially available and waste-derived sorbents. An application of the proposed framework is illustrated in a case study of a contaminated sediment site in Northern Belgium with high levels of As, Cd, Pb, and Zn originating from historical non-ferrous smelting. The framework was utilized to achieve the required remediation targets and to meet the imposed regulations on material application in natural environments.

Norway is faced with significant environmental problems posed by classical hydrophobic organic contaminants (HOCs) in marine sediments, including PAHs, PCBs, and polychlorinated dibenzodioxins and -furans in addition to newly recognized problem contaminants such as brominated flame retardants. Owing to high pollution levels, consumption restrictions exist for fish and other seafood from many fjord areas in Norway. Removal with subsequent treatment or disposal of all contaminated sediments would be a billion-kroner task, hence it is necessary to find practical and cost-effective methods to reduce the risk of HOCs in sediments without removing the material. Activated carbon amendment was applied as a novel remediation technique in a pilot project in Trondheim Harbour in 2008, co-financed by NFR and Trondheim Harbour Authorities. The project aimed at the establishment of novel pilot testing fields and their long-term follow-up and monitoring in Trondheim Harbor. The project consisted of thin-layer in situ capping with activated carbon (AC) implemented using three different methods: AC only, AC covered by a thin layer of sand, and AC mixed with clay.

This report begins with a literature review of documented soil remediation techniques tested for dioxins. A study was conducted to investigate the potential of using a photolytic catalyst (titanium dioxide) in combination with UV light to oxidize organic substances into water and carbon dioxide, and thus to remove the dioxins. In this method, pollutants are extracted into an aqueous solution, which then is treated by the oxidizing combination of UV light and TiO₂ catalyst. An efficient transfer into solution is accomplished by increasing colloid formation using a solution of sodium hydroxide (NaOH). After oxidation, the NaOH solution is recycled to the extraction phase and utilized again to the extent possible. A sub-study was conducted to optimize the colloid formation, where temperature, time of extraction, and concentration was varied in two types of soil. The efficiency of extraction varies greatly depending on how dioxins sorb to particles and the stage of organic material decomposition. In the most effective case—a soil with 6% relatively new organic material—only 20% of dioxins remained after extraction (measured in ng/kg WHO-TEQ). In the least effective case—a sandy soil containing 2% organic matter—the dioxin content doubled (measured in ng/kg WHO-TEQ) after treatment. Results indicate that dioxins in less weathered organic matter are easier to extract than dioxins in weathered material. Pretreatment with 90°C water conducted to remove chlorophenols from soil (which then can form dioxins if in an alkaline environment) was also effective for extracting dioxins. Almost equally good results were achieved with water extraction in comparison to NaOH extraction, and water is much easier to handle than NaOH. These results thus indicate new opportunities for manageable soil remediation. Appendix A offers a description of a pilot study of alkaline extraction of heavy hydrocarbons from soil.

In the implementation of electrochemical remediation, a direct-current electric field is imposed on contaminated soil to extract the contaminants by the combined mechanisms of electroosmosis, electromigration, and/or electrophoresis. The technology is particularly effective in fine-grained soils of low hydraulic conductivity and large specific surface area and can be applied to inorganic, organic, and mixed contaminants. The technology's effectiveness can be diminished by sorption of contaminants on soil particle surfaces and effects induced by hydrogen ions and hydroxide ions generated at the electrodes. Enhancement techniques have been developed to tackle these diminishing effects, and this paper contains a comprehensive review of the various techniques.

This study represents a snapshot in the evolution of final covers ~5 to 10 years after construction. This peer-reviewed study demonstrates that engineering properties of cover soils change while in service and that long-term engineering properties should be used as input to models employed for performance assessments. Increases in the saturated hydraulic conductivity, saturated volumetric water content, and the air entry suction (as characterized by van Genuchten's alpha parameter) occurred due to formation of soil structure, regardless of climate, cover design, or service life. Substantial changes in hydraulic conductivity were observed in some geosynthetic clay liners that did not hydrate completely and underwent cation exchange. Changes in geomembranes and geosynthetic drainage layers were modest or small, and computations based on antioxidant depletion rates suggest that the minimum service life of geomembranes is on the order of 50 to 125 yrs (the actual service life will be longer). The findings indicate that covers should be monitored to ensure that they are functioning as intended. Monitoring using pan lysimeters combined with secondary measurements collected for interpretive purposes is recommended. Future research investments should include an evaluation of remote sensing technologies for cover monitoring and analog studies to estimate properties of earthen and geosynthetic cover materials corresponding to service lives of hundreds to thousands of years. Section 2 provides background on the Alternative Cover Assessment Program (ACAP), which evaluated the performance of 27 different final cover profiles; describes the as-built profiles and properties of the test sections; and summarizes information from previous studies on factors that can lead to temporal change in the engineering properties of cover materials. Findings regarding earthen cover materials are described in Section 6, findings regarding geosynthetic clay liners are described in Section 7, and findings regarding geomembranes and geosynthetic drainage layers are described in Section 8. Volume 2 of this study contains appendices A through S. www.nrc.gov/reading-rm/doc-collections/nuregs/contract/cr7028/

This document comprises the first of two EPA reports that, together, will respond to the recommendations and comments on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) dose-response assessment in the 2006 NAS report, Health Risks from Dioxin and Related Compounds: Evaluation of the EPA Reassessment. This document, Reanalysis Volume 1, includes (1) a systematic evaluation of the peer-reviewed epidemiologic studies and rodent bioassays relevant to TCDD dose-response analysis; (2) dose-response analyses using a TCDD physiologically based pharmacokinetic model that simulates TCDD blood concentrations following oral intake; and (3) an oral reference dose for TCDD.