Cleanup levels for dioxin-contaminated soils

EPA's use of a 1 part per billion (ppb) level for dioxin contamination in residential soils is shown to be too high and not protective of public health. It was derived in a 1984 cancer risk assessment by another federal agency, but it is inconsistent with risk-based levels of 2 to 4 parts per trillion (ppt) obtained by using EPA's standard risk assessment methods. EPA has called the 1 ppb level a policy-based level, which correctly distinguishes it from a risk or health-based cleanup standard. The 1984 assessment is shown in this article to have considerable shortcomings. For over a decade, dioxins have been left in soils at levels posing health risks and sometimes at levels that EPA is legally required to address. Moreover, noncancer effects have been ignored, but recent work has shown them to support action at low ppt levels. To protect public health, be consistent with current scientific knowledge and other EPA policies, reduce confusion in the environmental management community, and be responsive to public demands for stringent dioxin cleanups, new EPA policy guidance for dioxin soil cleanups is needed, and key elements are presented in this article. In an ad hoc fashion, EPA Region 4 has recently used a 200 ppt dioxin cleanup level for residential soil, acknowledged to correspond to a one-in-ten-thousand cancer risk, at two Superfund sites, which environmental professionals should be aware of. This suggests a shift in EPA policy.     

Improving decision quality: Making the case for adopting next‐generation site characterization practices

Better site characterization is critical for cheaper, faster, and more effective cleanup. This fact is especially true as cleanup decisions increasingly include site redevelopment and reuse considerations. However, established attitudes about what constitutes “data quality” create many barriers to exciting new tools capable of achieving better characterization, slowing their dissemination into the mainstream. Traditional approaches to environmental “data quality” rest on simplifying assumptions that are rarely acknowledged by the environmental community. Data quality assessments focus on the quality of the analysis, while seldom asking what impact matrix heterogeneity has had on analytical results. Assessments of data quality typically assume that chemical contaminants are distributed nearly homogeneously throughout environmental matrices and that contaminant‐matrix interactions are well behaved during analysis. Yet, these assumptions seldom hold true for real‐world matrices and contaminants at scales relevant to accurate risk assessment and efficient remedial design. For the site cleanup industry to continue technical advancement, over‐simplified paradigms must give way to next‐generation models that are built on current scientific understanding. If reuse programs such as Brownfields are to thrive, the scientific defensibility of individual projects must be maintained at the same time as characterization and cleanup costs are lowered. The U.S. Environmental Protection Agency (EPA) offers the Triad Approach as an alternative paradigm to foster highly defensible, yet extremely cost‐effective reuse decisions. © 2003 Wiley Periodicals, Inc.     

Development of a site‐specific cleanup goal for PAHs in soil based on anthropogenic background levels

During removal of an industrial landfill in Folsom, California, fill material was excavated and processed through a mechanical screening plant to segregate soil from construction and demolition debris. The segregated soil was stockpiled and analyzed for a wide range of chemical groups to determine if the soil could be backfilled on‐site. The analytical results indicated many of the stockpiles had concentrations of polycyclic aromatic hydrocarbons (PAHs) that exceeded US EPA Regional Screening Levels, and a large quantity of soil was initially classified as requiring off‐site disposal at considerable cost. Because PAHs are ubiquitous in urban settings and the landfill did not contain a significant source of PAHs, development of a site‐specific PAH cleanup goal was proposed to regulators. Cal/EPA guidance for using on‐site data to develop a background threshold for metals was applied to the development of the PAH cleanup goal. The Cal/EPA approach involves demonstrating whether the data belong to a single population or multiple populations based on data distribution tests and probability plots. This article explains the statistical and graphical methods that were used to demonstrate that the Cal/EPA approach was valid for PAHs and that the calculated cleanup level was consistent with published anthropogenic background levels of PAHs in California and across the United States. The site‐specific PAH cleanup goal enabled most of the soil to be backfilled on‐site, saving about $227,000 in transportation and disposal costs, and regulators subsequently approved unrestricted future use of the property. © 2010 Wiley Periodicals, Inc.     

A Practical Guide to Estimating Cleanup Costs

Cost estimates are frequently developed to evaluate hazardous‐waste‐site cleanup options in support of a site investigation, remedy selection decision, or assessment of environmental liabilities. The accuracy of the cost estimate depends largely on the quality of the information available at the time it is prepared. This article presents a practical guide to developing a cleanup cost estimate. It includes information on how to document assumptions, use the latest technical resources, and perform basic adjustments to account for uncertainty and the time value of money. The content is based upon a recent guidance document issued by the U.S. Environmental Protection Agency and U.S. Army Corps of Engineers entitled A Guide to Developing and Documenting Cost Estimates during the Feasibility Study (USEPA, 2000). © 2001 John Wiley & Sons, Inc.     

Triad case study: Marine Corps Base Camp Pendleton

The U.S. Navy Public Works Center (PWC) Environmental Department, San Diego, California, is home to the Navy West Coast Site Characterization and Analysis Penetrometer System (SCAPS). SCAPS has been extensively used at several Navy sites since 1995 to provide real‐time, high‐density data sets. The U.S. Environmental Protection Agency's Triad approach provided an ideal framework for optimizing the use of the Navy SCAPS during a volatile organic compound (VOC) source investigation at Installation Restoration Site 1114 at Marine Corps Base Camp Pendleton. All three elements of Triad—systematic planning, dynamic work strategy, and use of real‐time measurement tools—were implemented to manage decision uncertainty and expedite the site management process. The investigation was conducted using the Navy SCAPS, outfitted with a cone penetrometer, membrane interface probe, and a direct sampling ion trap mass spectrometry detector, which allowed for real‐ time collection of over 690 feet of continuous lithologic information and VOC concentration data. These data were used collaboratively with 24‐hour turnaround US EPA 8260B VOC groundwater results from temporary direct‐ push wells to support the conclusion of a limited source area. Implementation of the Triad approach for this investigation provided an expedited high‐density data set and a refined conceptual site model (CSM) in real time that resulted in cost savings estimated at $2.5M and reduction of the site characterization and cleanup schedule by approximately three years. This project demonstrates how the US EPA's Triad approach can be applied to streamline the site characterization and cleanup process while appropriately managing decision uncertainty in support of defensible site decisions. © 2004 Wiley Periodicals, Inc.     

The Triad approach: A catalyst for maturing remediation practice

Many individual scientific and technical disciplines contribute to the multidisciplinary field of remediation science and practice. Because of the relative youth of this enterprise, disciplinary interests sometimes compete and conflict with the primary goal of achieving protective, cost‐effective, efficient projects. Convergence of viewpoints toward a more mature, common vision is needed. In addition, cleanup programs are changing under the influence of Brownfields initiatives and the needs of environmental insurance underwriters. Investigations and cleanups increasingly need to be affordable, yet transparent and defensible. Disciplinary goals and terminology need to better reflect real‐world site conditions while being more supportive of project needs. Yet, technical considerations alone will not ensure project success; better integration of human factors into project management is also required. The Triad approach is well placed to catalyze maturation of the remediation field because it emphasizes (1) a central theme of managing decision uncertainty; (2) unambiguous technical communications; (3) shortened project life‐cycles and multidisciplinary interactions that rapidly build professional expertise and provide feedback to test and perfect programmatic and field practices; and (4) concepts from “softer” sciences (such as economics, cognitive psychology, and decision theory) to capture important human factors. Triad pushes the cleanup industry toward an integrated, practical, second‐generation paradigm that can successfully manage the complexities of today's cleanup projects. © 2004 Wiley Periodicals, Inc.     

When the Going Gets Tough,Communities Believe It's Time to Optimize and Adapt

The people who live in the communities where complex groundwater sites are located are as diverse as the country itself, but those who fight for the cleanup of our groundwater recognize that total cleanup may be difficult, if not impossible, in our lifetimes. Still, as explained in a December 2013 joint letter to US EPA, we want those who are responsible for environmental protection, be they polluters, developers, or regulatory agencies, to try harder before admitting defeat. In Mountain View, California, community activists have developed criteria for the adaptive cleanup of the Moffett‐MEW Regional Plume of TCE groundwater contamination that emphasizes areas with high contaminant mass, source areas, locations that reduce the need for long‐term vapor intrusion mitigation, properties where the detectable plume encroaches on residential areas, schools, and other sensitive uses, and areas planned for reuse. In many other communities, trust is the key to developing community support for remedial strategies. Communities that are listened to tend to feel more empowered. Empowered communities tend to offer more constructive advice. Decision makers tend to listen to communities that offer constructive advice. In summary, when the cleanup going gets tough, empowered communities believe that it is time to optimize and adapt, not to give up. © 2014 Wiley Periodicals, Inc.     

Methodology and model for performance and cost comparison of innovative treatment technologies at wood preserving sites

Wood preserving facilities have used a variety of compounds, including pentachlorophenol (PCP), creosote, and certain metals, to extend the useful life of wood products. Past operations and waste management practices resulted in soil and water contamination at a portion of the more than 700 wood preserving sites in the United States (EPA, 1997). Many of these sites are currently being addressed under federal, state, or voluntary cleanup programs. The U.S. Environmental Protection Agency (EPA) National Risk Management Research Laboratory (NRMRL) has responded to the need for information aimed at facilitating remediation of wood preserving sites by conducting treatability studies, issuing guidance, and preparing reports. This article presents a practical methodology and computer model for screening the performances and comparing the costs of seven innovative technologies that could be used for the treatment of contaminated soils at user‐specified wood preserving sites. The model incorporates a technology screening function and a cost‐estimating function developed from literature searches and vendor information solicited for this study. This article also provides background information on the derivation of various assumptions and default values used in the model, common contaminants at wood preserving sites, and recent trends in the cleanup of such sites. © 2001 John Wiley & Sons, Inc.     

Assessing cleanup levels for industrial sites under state risk reduction programs

Many states are promoting the cleanup and reuse of industrial sites. The reasons stem from the need to implement cost-effective risk reduction programs that show reasonable progress in the cleanup of contaminated sites and from the need to make effective use of industrial sites instead of abandoning them and making use of greenfield sites for new industrial facilities. The industrial land-use cleanup criteria developed by states are primarily risk-based. Several EPA regional offices also have developed similar risk-based cleanup criteria. This article addresses methodologies employed for assessing and evaluating the level of cleanup at several industrial sites in Texas, Michigan, and Ohio. This includes defining the regulatory framework, estimating the level and extent of contamination of soil and groundwater, assessing migration pathways, performing health risk assessments, and estimating cleanup requirements and associated costs. The implications associated with the various types of risk reduction options available for these states also are addressed.     

Applying sustainable development principles to contaminated land management using the SuRF‐UK framework

In the past decade, management of historically contaminated land has largely been based on prevention of unacceptable risks to human health and the environment, to ensure a site is “fit for use.” More recently, interest has been shown in including sustainability as a decision‐making criterion. Sustainability concerns include the environmental, social, and economic consequences of risk management activities themselves, and also the opportunities for wider benefit beyond achievement of risk‐reduction goals alone. In the United Kingdom, this interest has led to the formation of a multistakeholder initiative, the UK Sustainable Remediation Forum (SuRF‐UK). This article presents a framework for assessing “sustainable remediation”; describes how it links with the relevant regulatory guidance; reviews the factors considered in sustainability; and looks at the appraisal tools that have been applied to evaluate the wider benefits and impacts of land remediation. The article also describes how the framework relates to recent international developments, including emerging European Union legislation and policy. A large part of this debate has taken place in the “grey” literature, which we review. It is proposed that a practical approach to integrating sustainability within risk‐based contaminated land management offers the possibility of a substantial step forward for the remediation industry, and a new opportunity for international consensus. © 2011 Wiley Periodicals, Inc.     

Systematic planning for Triad projects

This article examines specific systematic planning steps that can be used for designing and controlling Triad projects. Triad work strategies act to limit decision uncertainty, expedite schedules to meet project milestones, and reduce costs associated with cleanup activities. As a result, the Triad approach is rapidly increasing in popularity. Good project planning has always been seen as the cornerstone of successful Triad projects. However, the specific steps in the systematic planning process have not been extensively published. Demands of Triad projects, which attempt to make maximum use of innovative technologies and sequencing of activities in a learn‐ as‐you‐go framework, put new demands on regulators and project managers alike. Specific activities and relationships are identified to assist project managers with dynamic work strategies and real‐time measurements to support improved decision making. These include: assembly of stakeholders, a core technical team, and key decisions; development and refinement of a site model; use of demonstrations of methods applicability; development of dynamic work strategies and project sequencing; real‐time data management assessment and presentation; and unitized procurement of technologies and services. © 2004 Wiley Periodicals, Inc.     

A deterministic approach to evaluate and implement monitored natural attenuation for chlorinated solvents

A US EPA directive and related technical protocol outline the information needed to determine if monitored natural attenuation (MNA) for chlorinated solvents is a suitable remedy for a site. For some sites, conditions such as complex hydrology or perturbation of the contaminant plume caused by an existing remediation technology (e.g., pump‐and‐treat) make evaluation of MNA using only field data difficult. In these cases, a deterministic approach using reactive transport modeling can provide a technical basis to estimate how the plume will change and whether it can be expected to stabilize in the future and meet remediation goals. This type of approach was applied at the Petro‐Processors Inc. Brooklawn site near Baton Rouge, Louisiana, to evaluate and implement MNA. This site consists of a multicomponent nonaqueous‐phase source area creating a dissolved groundwater contamination plume in alluvial material near the Mississippi River. The hydraulic gradient of the groundwater varies seasonally with changes in the river stage. Due to the transient nature of the hydraulic gradient and the impact of a hydraulic containment system operated at the site for six years, direct field measurements could not be used to estimate natural attenuation processes. Reactive transport of contaminants were modeled using the RT3D code to estimate whether MNA has the potential to meet the site‐specific remediation goals and the requirements of the US EPA Office of Solid Waste and Emergency Response Directive 9200.4‐17P. Modeling results were incorporated into the long‐term monitoring plan as a basis for evaluating the effectiveness of the MNA remedy. As part of the long‐term monitoring plan, monitoring data will be compared to predictive simulation results to evaluate whether the plume is changing over time as predicted and can be expected to stabilize and meet remediation goals. This deterministic approach was used to support acceptance of MNA as a remedy. © 2007 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.     

Developing Effective Decision Support for the Application of “Gentle” Remediation Options: The GREENLAND Project

Gentle remediation options (GRO) are risk management strategies/technologies that result in a net gain (or at least no gross reduction) in soil function as well as risk management. They encompass a number of technologies, including the use of plant (phyto‐), fungi (myco‐), and/or bacteria‐based methods, with or without chemical soil additives or amendments, for reducing contaminant transfer to local receptors by in situ stabilization, or extraction, transformation, or degradation of contaminants. Despite offering strong benefits in terms of risk management, deployment costs, and sustainability for a range of site problems, the application of GRO as practical on‐site remedial solutions is still in its relative infancy, particularly for metal(loid)‐contaminated sites. A key barrier to wider adoption of GRO relates to general uncertainties and lack of stakeholder confidence in (and indeed knowledge of) the feasibility or reliability of GRO as practical risk management solutions. The GREENLAND project has therefore developed a simple and transparent decision support framework for promoting the appropriate use of gentle remediation options and encouraging participation of stakeholders, supplemented by a set of specific design aids for use when GRO appear to be a viable option. The framework is presented as a three phased model or Decision Support Tool (DST), in the form of a Microsoft Excel‐based workbook, designed to inform decision‐making and options appraisal during the selection of remedial approaches for contaminated sites. The DST acts as a simple decision support and stakeholder engagement tool for the application of GRO, providing a context for GRO application (particularly where soft end‐use of remediated land is envisaged), quick reference tables (including an economic cost calculator), and supporting information and technical guidance drawing on practical examples of effective GRO application at trace metal(loid) contaminated sites across Europe. This article introduces the decision support framework. ©2015 Wiley Periodicals, Inc.     

A risk-based approach to how clean is clean

Clearly defined remedial action objectives are a key factor in successful remediation programs. Chemical-specific cleanup criteria are critical components of remedial action objectives. A common risk-based approach can be applied for developing cleanup criteria for remediations under CERCLA, RCRA, and TSCA. This approach involves four steps: identify regulatory requirements; identify chemical-specific cleanup guidelines from previous cleanups; evaluate site-specific risk considering mitigating factors for a given site; select the final cleanup criteria based on information from the first three steps. To describe this approach, this paper presents a case study on a PCB cleanup conducted under TSCA. An objective risk-based approach was used to capitalize on the flexibility built into EPA's PCB cleanup guidelines. EPA granted an exemption to the stated policy on the basis of competing risk factors using a comparative risk-assessment approach. Similarly, risk assessment can be used to take advantage of regulatory flexibility in the selection of applicable or appropriate and relevant requirements (ARARs) under CERCLA, or in the selection of media protection standards under RCRA.     

In Situ solidification—A case study at a former manufactured gas plant in Macon,Georgia

In situ solidification (ISS) is a reliable, EPA‐recognized technology for the treatment of industrial and waste sites. ISS was employed at a former manufactured gas plant (MGP) site in Macon, Georgia, for the treatment of approximately 33,000 cubic yards of coal tar residues in the saturated zone soil. The site is regulated by the Georgia Environmental Protection Division (EPD) under the Hazardous Site Rehabilitation Act (HSRA) and is located approximately four blocks from downtown Macon. This article will review the technical and regulatory basis for the successful use of this technology, provide an overview of the treatability and pilot testing used to develop the design and implementation of the treatment process, and present the results of the application of ISS to an MGP site. The results of groundwater monitoring, pre and postremediation, will also be discussed. © 2004 Wiley Periodicals, Inc.     

Approaches for assessing hazards and risks to workers and the public from contaminated land

Many public agencies and private entities are faced with assessing the risks to humans from contamination on their lands. The United States Department of Energy (US DOE) and Department of Defense are responsible for large holdings of contaminated land and face a long‐term and costly challenge to assure sustainable protectiveness. With increasing interest in the conversion of brownfields to productive uses, many former industrial properties must also be assessed to determine compatible future land uses. In the United States, many cleanup plans or actions are based on the Comprehensive Environmental Responsibility, Compensation, and Liability Act, which provides important but incomplete coverage of these issues, although many applications have tried to involve stakeholders at multiple steps. Where there is the potential for exposure to workers, the public, and the environment from either cleanup or leaving residual contamination in place, there is a need for a more comprehensive approach to evaluate and balance the present and future risk(s) from existing contamination, from remediation actions, as well as from postremediation residual contamination. This article focuses on the US DOE, the agency with the largest hazardous waste remediation task in the world. Presented is a framework extending from preliminary assessment, risk assessment and balancing, epidemiology, monitoring, communication, and stakeholder involvement useful for assessing risk to workers and site neighbors. Provided are examples of those who eat fish, meat, or fruit from contaminated habitats. The US DOE's contaminated sites are unique in a number of ways: (1) huge physical footprint size, (2) types of waste (mixed radiation/chemical), and (3) quantities of waste. Proposed future land uses provide goals for remediation, but since some contamination is of a type or magnitude that cannot be cleaned up with existing technology, this in turn constrains future land use options, requiring an iterative approach. The risk approaches must fit a range of future land uses and end‐states from leave‐in‐place to complete cleanup. This will include not only traditional risk methodologies, but also the assessment and surveillance necessary for stewards for long‐term monitoring of risk from historic and future exposure to maintain sustainable protectiveness. Because of the distinctiveness of DOE sites, application of the methodologies developed here to other waste site situations requires site‐specific evaluation © 2007 Wiley Periodicals, Inc.     

The active role of state laws in superfund cleanups

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) did not ignore the fifty individual states when establishing responsibility, authority, and liability for cleaning up hazardous waste sites. Although CERCLA gives EPA the ultimate authority to select a remedy for a contaminated site, the law was drafted not only to allow for state activity without EPA, but also for significant state input when EPA is involved. The relationship between a state (and its environmental laws) and EPA can help decide the remedial and financial interests of any potentially responsible party (PRP). This article discusses the relevant CERCLA provisions, recent court decisions, and resolved and unresolved issues in federal-state Superfund involvement, and recommends several common-sense strategies for PRPs when working with a state in a Superfund cleanup.     

Accelerating environmental cleanup at DOE sites: Monitored natural attenuation/enhanced attenuation—A basis for a new paradigm

The U.S. Department of Energy is conducting a project to accelerate remediation through the use of monitored natural attenuation and enhanced attenuation for chlorinated ethenes in soils and groundwater. Better monitoring practices, improved scientific understanding, and an advanced regulatory framework are being sought through a team effort that engages technology developers from academia, private industry, and government laboratories; site cleanup managers; stakeholders; and federal and state regulators. The team works collaboratively toward the common goals of reducing risk, accelerating cleanup, reducing cost, and minimizing environmental disruption. Cutting‐edge scientific advances are being combined with experience and sound environmental engineering in a broadly integrated and comprehensive approach that exemplifies socalled “third‐generation R&D.” The project is potentially a model for other cleanup activities. © 2004 Wiley Periodicals, Inc.