Contaminant dynamics: Key to remedial performance and regulatory relief

Remediation results depend on thorough consideration of all the forces that influence contaminant behavior, including how the contaminant is distributed and the site's hydrogeology, as well as the physical, chemical, and biological factors involved in contaminant mobility and persistence. This information supports a cleanup project's initial investigation, helping decide the goals of the later remediation method, the usefulness of specific technologies, and the method's ultimate performance. This article discusses how the principal environmental and chemical processes influence contaminant fate and transport and explores four case histories that illustrate how that influence can help predict whether a project's goals are achievable, whether the project is needed at all, and whether those goals were actually achieved.     

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The State of Washington's Model Toxics Control Act cleanup standards, argues the author, provide the best available strategy for setting and achieving cleanup goals. Besides Protecting human health and the natural environnment, Washington's guidelines, which took effect March 1, 1991, incorporate enough flexibility to handle site-specific, finaical, and tehnological considerations. This column outlines the law's three approaches for defining cleanup levels for groundwater, surface water, air, industrial soils, and nonindustrial soils, comparing these methods with related methods in California, New Jersey, and New York.     

Hydrogen peroxide for physicochemically degrading petroleum-contaminated soils

Catalyzed hydrogen peroxide was applied to contaminated soil at an equipment storage yard in Reno, Nevada, that had also been used as a dump for motor oil and diesel fuel for twenty years. The site is only a quarter mile from the Truckee River—a principal source of Reno's drinking water. This article details hydrogen peroxide's advantages, disadvantages, costs, and treatment for reducing to below the 100 mg/kg Nevada action level the petroleum hydrocarbons in the yard's arid soil, which is characterized by low organic carbon content and low manganese oxide content.     

Evaluation of a vertical frozen soil barrier at oak ridge national laboratory

Arctic Foundations, Inc. (AFI), of Anchorage, Alaska, has developed a freeze barrier system designed to hydraulically isolate a contaminant source area. The system can be used for long‐term or temporary containment of groundwater until appropriate remediation techniques can be applied. The technology was evaluated under the United States Environmental Protection Agency's (EPA's) Superfund Innovative Technology Evaluation (SITE) program at the United States Department of Energy's (DOE's) Oak Ridge National Laboratory (ORNL) facility in Oak Ridge, Tennessee. For the demonstration, an array of freeze pipes called “thermoprobes” was installed to a depth of 30 feet below ground surface around a former waste collection pond and keyed into bedrock. The system was used to establish an impermeable frozen soil barrier to hydraulically isolate the pond. Demonstration personnel collected independent data to evaluate the technology's performance. A variety of evaluation tools were used—including a groundwater dye tracing investigation, groundwater elevation measurements, and subsurface soil temperature data—to determine the effectiveness of the freeze barrier system in preventing horizontal groundwater flow beyond the limits of the frozen soil barrier. Data collected during the demonstration provided evidence that the frozen soil barrier was effective in hydraulically isolating the pond.     

Remediation and review: Developing groundwater strategy at the hanford site

The U.S. Department of Energy's (US DOE's) environmental challenges include remediation of the Hanford Site in Washington State. The site's legacy from nuclear weapons “production” activities includes approximately 80 square miles of contaminated groundwater, containing radioactive and other hazardous substances at levels above drinking water standards. In 1998, the U.S. General Accounting Office (US GAO), the auditing arm of Congress, concluded that groundwater remediation at Hanford should be integrated with a comprehensive understanding of the “vadose zone,” the soil region between the ground surface and groundwater. The US DOE's Richland Operations Office adjusted its program in response, and groundwater/vadose‐zone efforts at Hanford have continued to develop since that time. Hanford provides an example of how a federal remediation program can be influenced by reviews from the US GAO and other organizations, including the US DOE itself. © 2008 Wiley Periodicals, Inc.     

Modified Fenton's processes for effective in‐situ chemical oxidation—Laboratory and field evaluation

Fenton's reagent in its conventional form, although effective for contaminant treatment, is impractical from an in‐situ field application perspective due to low pH requirements (i.e., pH 3‐4), and limited reagent mobility when introduced into the subsurface. Modified Fenton's processes that use chelated‐iron catalysts and stabilized hydrogen peroxide have been developed with the goal of promoting effective in‐situ field application under native pH conditions (i.e., pH 5‐7), while extending the longevity of hydrogen peroxide. Laboratory experiments conducted in soil columns packed with organic soil to compare modified Fenton's catalysts with conventional catalysts (acidified iron [II]) indicated superior mobility and sorption characteristics for modified Fenton's catalysts. Furthermore, the acidic pH of a conventional catalyst was buffered to the native soil range, leading to increased iron precipitation/adsorption following permeation through the soil column. The chelates present within the modified Fenton's catalyst showed greater affinity toward iron compared with the native soil and, hence, minimized iron loss through adsorption during the permeation process even at pH 5‐7. Field effectiveness of the modified Fenton's process was demonstrated at a former dry‐cleaning facility located in northeast Florida. Preliminary laboratory‐scale experiments were conducted on soil‐slurry and groundwater samples to test the process efficacy for remediation of chlorinated solvents. Based on successful experimental results that indicated a 94 percent (soil slurry) to 99 percent (groundwater) reduction of cis‐1,2‐DCE, PCE, and TCE, a field‐scale treatment program was initiated utilizing a plurality of dual‐zone direct push injection points installed in a grid fashion throughout the site. Results of treatment indicated a 72 percent reduction in total chlorinated contamination detected in the site groundwater following the first injection event; the reduction increased to 90 percent following the second injection event. © 2002 Wiley Periodicals Inc.     

Remediation,land use,and risk at Rocky Flats,and a comparison with Hanford

US Department of Energy (US DOE) responsibilities for its former national atomic weapons complex include remediation of the Rocky Flats facility near Denver, Colorado. In 1993, the site's primary mission shifted from “production'' of plutonium components for atomic weapons to cleanup of extensive radioactive and chemical contamination representing the legacy of production activities. Remediation was governed by the agreements between the US DOE as the responsible party and the US Environmental Protection Agency and the state of Colorado as joint regulators. In 1995, the Rocky Flats Future Use Working Group issued its final report, recommending among other features that long‐term cleanup reduce contamination levels to background. This article describes the circumstances that led the US DOE to complete the Rocky Flats cleanup more quickly and makes comparisons to the situation at the US DOE's Hanford site. © 2011 Wiley Periodicals, Inc.     

Nuclear waste disposition and site remediation: U.S. department of energy,state governments,and other stakeholders dialogue

Remediation responsibilities of the U.S. Department of Energy (DOE) encompass a vast national complex of highly contaminated former weapons facilities. During the mid‐1990s, DOE announced its intentions to consolidate some waste types at specific sites. At about the same time, organizations and public officials around DOE sites urged a National Dialogue, designed to develop comprehensive solutions to the Department's needs for waste disposition ( transportation, treatment, and storage). Recent opposition from citizens and elected officials in Nevada and Washington State has presented obstacles to DOE's plans. Additionally, chairs of nine site‐specific advisory boards recommended that DOE support a National Stakeholder Forum, similarly designed to develop solutions to disposition needs. This article reviews the chronology of DOE's disposition efforts, along with public and state reactions and recommendations. © 2006 Wiley Periodicals, Inc.     

The Use of Zero‐Valent Iron (ZVI) Technology to Promote DDT and Dieldrin Degradation at Point Pelee National Park

Point Pelee National Park (PPNP) is highly contaminated with dichlorodiphenyltrichloroethane (DDT) and dieldrin due to the historical use of these two persistent organochlorine pesticides. Zero‐valent iron (ZVI) technology with and without amendments has been successfully used in the past to promote organochlorine pesticides degradation in several locations in North America and Europe. In this study, the use of two commercially available ZVI products, DARAMEND^® and EHC^®, to promote DDT and dieldrin degradation in PPNP's soil and groundwater were investigated. DARAMEND^® was applied to PPNP's soil in a laboratory experiment and in an in situ pilot‐scale plot. In both cases, DARAMEND^® did not significantly increase DDT or dieldrin degradation in treated soils. The effectiveness of EHC^® was tested in a laboratory experiment that simulated the park's groundwater environment using PPNP's pesticide contaminated soil. The result was consistent with the one reported for DARAMEND^®, in that there was no significant increase in DDT or dieldrin degradation in any of the samples treated with EHC^®. These results demonstrate that both of these ZVI commercially available products are not suitable for in situ remediation at PPNP.  ©2017 Wiley Periodicals, Inc.     

Rethinking groundwater monitoring at the Hanford Site

Groundwater monitoring at Department of Energy's (DOE's) Hanford Site is a large, expensive undertaking serving multiple purposes, including compliance with regulations and DOE orders, remediation efforts under CERCLA, and sitewide risk evaluations. Like most large Federal facilities, the monitoring program currently in place has evolved and grown overtime as new requirements were established and groups were assigned to address them. DOE and its regulators simultaneously awakened to the fact that there was a need to reevaluate the monitoring activities at Hanford, to better integrate the program, to avoid duplicative sampling, to improve everyone's understanding of the performance of the network, and to evaluate whether adequate data could be collected for lower cost. This paper describes the approch that was developed to guide the rethinking effort with direct and extensive involvement of DOE, EPA, Washington Department of Ecology, Indian Tribes, and DOE Contractors, and how this approach was applied to a large portion of the site. Both the human element of the process (cultural change), as well as some of the technical details associated with the effort, including a flexible application of EPA's data quality objectives process, are discussed.     

Use of Fenton's Reagent as a Disinfectant

Several compositions of Fenton's Reagent and hydrogen peroxide alone were used to disinfect combined sewage samples from a wastewater treatment facility. The presettled samples contained suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L, respectively. Disinfection with Fenton's Reagent was carried out at a pH between 5.90 and 6.0 and at a temperature of 25°C. All disinfected samples contained residual oxidants. Under all reaction conditions studied, complete inactivation of E. coli was achieved within one minute of the addition of Fenton's Reagent. Disinfection with hydrogen peroxide alone under similar conditions is incomplete even under much longer contact times. © 2009 Wiley Periodicals, Inc.     

Hanford remediation at 20 years: A glass half‐empty

The U.S. Department of Energy's (US DOE's) responsibilities for its former national nuclear weapons complex include remediation of the Hanford Site in Washington State. In 1989, the site's primary mission shifted from nuclear weapons material production to cleanup of the extensive radioactive and chemical contamination that represented the production legacy. Cleanup is governed by the Tri‐Party Agreement (TPA), between the US DOE, as responsible party, and the U.S. Environmental Protection Agency and Washington State Department of Ecology, as joint regulators. Nearly 20 years have passed since the TPA was signed, but the Hanford remediation is expected to require decades longer. This article covers the cleanup progress to date and challenges that remain, particularly from millions of gallons of highly radioactive liquid wastes and proposals to bring new wastes to Hanford. © 2008 Wiley Periodicals, Inc.     

Rocky Flats,plutonium, and controversy: Citizen activists provide institutional memory

The U.S. Atomic Energy Commission (AEC) selected Rocky Flats, east of the Rocky Mountains, as the site to fabricate “plutonium pits,” triggers for H‐bombs, and operations began in 1952. Press reports revealed the plant's connection to atomic weapons in 1956. Denver is downwind and “downslope” by about 16 miles. As western suburbs moved closer to Rocky Flats over time, plant accidents sent plutonium and other contaminants offsite. In 1989, armed agents of the U.S. Environmental Protection Agency (EPA) and Federal Bureau of Investigation raided the facility, and the plant operator, Rockwell International, subsequently pleaded guilty to criminal environmental violations. By this time, the U.S. Department of Energy had inherited responsibility for Rocky Flats and atomic weapons production. In 1993, the primary mission at Rocky Flats became cleanup of contamination from plutonium and other hazardous substances. Under Energy's “Accelerated Cleanup” plan, remediation was certified complete in 2005 by the Department's cleanup regulators, EPA, and the Colorado Department of Public Health. But planned uses for the “buffer zone” around the facility's central industrial area, and for off‐site areas continued to generate public controversy. This article examines the controversy and reports on general “stewardship” concepts for long‐term waste management.     

Stabilization and a multimedia cap for a doe mixed waste site

Closure often of the eleven waste management units covering almost seventy-five acres at the U.S. Department of Energy's Oak Ridge Y-12 Plant has been completed. Costing about $47 million, DOE's accelerated Closure and Post Closure Program (CAPCA) has involved structural waste stabilization and installation of a multimedia cap to contain ferrous metals, salts, uranium, solvents, ethylenediamine tetraacetic acid (EDTA), oils and coolants, asbestos, and material contaminated with radioisotopes. Designs for closure of the remaining waste unit—used for disposing depleted uranium chips, metals, oxides, organic and caustic chemicals, aged ethers, and more—are being prepared now; they will address the potentially explosive and pyrophoric nature of these wastes. This article describes CAPCA's innovative design and construction methods, as well as how its management coordinated the tight schedules mandated by agreements with federal and state regulatory agencies.     

How shell cleaned up a 400,000-gallon oil spill

On April 23, 1988, approximately 9,500 barrels (400,000 gallons) of San Joaquin Valley crude oil leaked from an aboveground storage tank at Shell Oil Company's Martinez Manufacturing Complex in Martinez, California and entered Suisun Bay, an important recreation area. This article describes the remediation techniques Shell used to protect and clean up the Bay's oiled marshes, sloughs, rocky shores, marinas, and sandy beaches, and discusses the main methods of oil spill response, site-specific factors that must be considered in choosing remediation techniques, the interaction between Shell and government agencies, and the costs associated with the spill. The cleanup's total cost was approximately $8.3 million, which did not include private claims and claims handling costs; Shell also signed a separate consent decree for $19.75 million with the state of California and the federal government. This spill and its aftermath emphasize the need for preparation that facilitates response actions, improves the chances for cooperation between responsible parties and government agencies, minimizes the time needed for remediation, lowers cleanup costs, and limits natural resource damage claims and penalties.     

California's Low‐Threat LUFT Site Closure Policy: Looking Forward

California's regulatory agencies have historically been at the forefront of national efforts to address environmental concerns. In 2012, California's agency for addressing leaking underground fuel tanks (LUFTs) adopted a policy that identifies low‐threat conditions warranting closure of an LUFT case. That development clearly fulfills the role of risk management in the risk assessment–risk management paradigm inherent in environmental remediation. It also encourages identification of additional categories of sites and other circumstances that are “low threat” to develop similar guidance on closure to apply to those sites. ©2015 Wiley Periodicals, Inc.     

NYSDEC's DER‐31/Green Remediation Policy Influences Tool Development and Global Program

The New York State Department of Environmental Conservation (NYSDEC) Division of Environmental Remediation (DER) issued a program policy focused on the overall sustainability of hazardous waste site cleanups on August 11, 2010. This DER‐31/Green Remediation program policy (DER‐31) was issued in accordance with 6 New York Codes, Rules and Regulations (NYCRR) Part 375 Environmental Remediation Programs. DER‐31 represents one of the first government‐issued green and sustainable remediation (GSR) policies in the United States. Consistent with other DER policies, DER‐31's provisions are broadly considered to be an expectation/requirement. GSR experts from within AECOM's Remediation Services (RS) Practice Area developed and implemented a GSR program designed to comply with DER‐31 provisions and have now broadly incorporated GSR into our New York remediation projects. Lessons learned from this experience in New York have influenced AECOM's global GSR program and implementation procedures and prompted the development of a new GSR tool (GSRx^TM) for identifying and assessing GSR best management practices (BMPs), which has also been employed globally. © 2013 Wiley Periodicals, Inc.     

Australia's National Plan to Combat Pollution of the Sea by Oil and Other Noxious and Hazardous Substances – Overview and Current Issues

Australia's National Plan to Combat Pollution of the Sea by Oil and Other Noxious and Hazardous Substances (the National Plan) has operated since 1973. The objectives of the National Plan are based on Australia's obligations as a signatory to the International Convention on Oil Pollution Preparedness, Response and Co-operation 1990 and a responsibility to protect natural and artificial (man made) environments from the adverse effects of oil pollution and minimise those effects where protection is not possible.The Australian Maritime Safety Authority (AMSA) is the managing agency of the National Plan, working together with the States and Northern Territory governments, other Commonwealth agencies, ports, and the shipping, oil and exploration industries, to maximise Australia's marine pollution response capability.The 1990s have been a period of significant change for oil spill response arrangements in Australia. The National Plan was extended in 1998 to cover chemical spills and is currently in the process of implementing the oil spill response incident control system (OSRICS). A fixed wing aerial dispersant spraying capability was implemented in 1996 and a research and development program has been put in place. The development of a computer-based National Oil Spill Response Atlas was a major project completed during 1999.     

Current status and challenges of remediating petroleum‐derived PAHs in soils: Nigeria as a case study for developing countries

Polycyclic aromatic hydrocarbons (PAHs) are among the world's most significant environmental organic contaminants because of their carcinogenic properties. PAHs are widely distributed globally as a result of releases from numerous natural and anthropogenic activities. Consequently, several PAH monitoring studies have been conducted and remediation approaches explored. This article aims to provide the current status of PAH distribution in Nigeria's oil and gas industrial region in relation to the technologies adopted for PAH remediation. Ideally, the findings will provide insight into the challenges in managing organic contaminants derived from petroleum exploration activities in developing countries with Nigeria as a case study.     

Look at groundwater quality to set VOC cleanup levels

In 1981, the Arizona Department of Health Services (ADHS) discovered groundwater contamination by solvents and chromium at the Phoenix Goodyear Airport (PGA), just outside the city of Phoenix. ADHS and the U.S. EPA sampled the site for the next two years, finding that eighteen of their wells were contaminated with trichloroethene (TCE), six exceeding ADHS's action level of five micrograms per liter (μg/l). In 1983, the PGA site was added to the National Priorities List, and, in 1984, EPA began a $3 million remedial investigation, focusing on soils and groundwater. This article discusses how that investigation inspired the authors to develop a stream-lined evaluation method for PGA's volatile organic compounds (VOCs), the process for establishing VOC cleanup levels, and the $26 million of remediation work needed to be done at the site. The heart of this effort is a computer program called VLEACH, loosely standing for VOC-LEACHing, which anticipates the influence of VOCs on PGA's groundwater, even as remediation proceeds.