Risk-Based Corrective Action and Brownfields Restorations

Urban planners and economic developers, especially at local levels, are faced with the cost of determining contamination levels at their Brownfields sites. Often they find themselves unable to respond to information requests from prospective purchasers and property developers, on whether sites within their jurisdiction are contaminated, and if so, the potential cleanup liabilities. The general practice has been to engage environment consultants or in-house technical staff to conduct site assessments, following Superfund investigation models required by federal and state governments. These investigations generally utilize conventional sampling and analytical methods which are costly and time consuming. New innovative, field assessment technologies are emerging and reaching the market place which lend themselves well to gathering the data in a timely way to answer questions that are asked by those interested in Brownfields sites. This paper will identifY those questions, provide a summary of some of the advancing technologies, discuss the ways that the data collection can be expanded and accelerated and define some of the barriers that must be overcome for regulatory acceptance of those technologies.

Risk assessment is used and accepted by U.S. regulatory agencies as an objective means of identifying sites that may need remediation, and as a tool helping to determine the most appropriate remedial action. Risk-based strategies can support identification of remedies that are both protective of health and the environment and cost-effective. For example, risk assessment can be used to estimate the risk posed by a site in the absence of remedial action; focus site characterization activities; establish remedial action objectives; and compare alternative remedies for achieving those objectives. This paper provides a brief overview of the basic principles of risk assessment, identifies assumptions made during the baseline risk assessment that can have a significant effect on remediation decisions and discusses the use of risk assessment in the remedy selection process. Case histories are also presented to illustrate key risk assessment issues.

Corrective action has traditionally been a sequence of steps taken at a site where hazardous substances or petroleum have been released to restore the site to a pre-release condition. Under many current regulatory corrective action programs a number of steps have been defined. Each step must be completed and the results approved by the regulatory agency before the next step can begin. This has resulted in each step taking on a life of its own, with objectives existing for the sake of that step that are disconnected from the overall corrective action objectives. Unfortunately, the complexities and costs of the traditional corrective action process have left many properties' abandoned or in perpetual corrective action. Recently, however, there has been growing recognition that the traditional corrective action process must be modified to encourage faster and less costly corrective actions. To address these needed modifications and to develop a standard framework that incorporates and integrates site-specific risk-based decision making into the corrective action process, in 1995 ASTM developed Standard E-1739, "Guide to Risk-Based Corrective Action for Petroleum Release Sites& commonly referred to as RBCA (pronounced Rebecca). In 1998 ASTM expanded the RBCA framework to include all chemicals with the development of Provisional Standard PS104-98, &Standard Guide for Risk-Based Corrective Action.& The RBCA framework provides a three tier process that begins with a simple, conservative screening approach in Tier 1 and proceeds to more complex, site-specific evaluations in Tier 2 and Tier 3. The objective of RBCA is to provide for protection of human health and the environment while insuring that appropriate, cost-effective and technically defensible approaches and remedies are selected. This paper will discuss the evolution of the traditional corrective action process to a site-driven process and the fundamentals of the ASTM RBCA framework.

The need for environmental systems modeling is growing rapidly because of the 1) combination of increasing technical scope and complexity related to questions of risk-based cause and effect and 2) need to explicitly address cost effectiveness in both the development and implementation of environmental regulations. The nature of risk assessments are evolving with their increased complexity in assessing individual sites and collection of sites, addressing regional or national regulatory needs. These assessments require the integration of existing tools and the development of new databases and models, based on a comprehensive and holistic view of the risk assessment problem. To meet these environmental regulatory needs, multiple-media-based assessments are formulated to view and assess risks from a comprehensive environmental systems perspective, crossing the boundaries of several scientific disciplines. Given the consideration and the advanced states of computer hardware and software, it is possible to design a software system that facilitates the development and integration of assessment tools (e.g., databases and models). In this paper, a risk-based approach for supporting national risk assessments is presented. This approach combines 1) databases, 2) multiple media models, combining source-term, fate and transport, exposure, and risk/hazard, and 3) sensitivity/uncertainty capabilities within a software system capable of growing within the science of risk assessment. The design and linkages of the system are discussed. This paper also provides the rationale behind the design of the framework, as there is a recognized need to develop more holistic approaches to risk assessment.

The American Society for Testing and Materials is proposing a Standard Guide to the Process of Sustainable Brownfields Redevelopment. The Standard Guide provides a logical framework for carrying forth the process of Brownfields redevelopment in a multi-stakeholder environment. The process is defined in four components: initiation, which is where the vision for the property is presented to the stakeholders; evaluation, where the environmental, regulatory, and financial viability of the project is determined; transaction, where the property actually changes hands; and implementation, where the redevelopment is carried out according to the consensus developed through the multi-stakeholder process. Three examples are cited where a multi-stakeholder process as described in the Standard Guide is used to streamline the Brownfields redevelopment process. These case studies demonstrate that by developing an open, consensus-based community participation program that addresses stakeholder concerns about potential impacts to the community or exposure to constituents of concern, one can streamline the Brownfields redevelopment process. The Standard Guide recommends the use of risk-based decision making that targets corrective action objectives that meet the intended land use. The Standard Guide provides a ptocess for completing each component of the Brownfields redevelopment process in a multi-stakeholder environment, providing information gathered regarding best practices from communities across the United States and internationally.

A process based model for contaminant transport through slurry wall was developed. The model was applied to a Browntield site contained by slurry walls. The flow towards and through the slurry wall by advection and diffusion was calculated. The concentrations at the boundary of the property were provided as input to CalTOX model and the risk due to contaminant was calculated. Risk was projected for next 30 years. This type of approach is useful for developers for selecting proper application with minimal risk at a Brownfield site.

Risk management is, by definition, a process of managing potential risks. In the environmental arena, risk management is often based on a Risk-Based Corrective Action (RBCA) process, which is generally only considered at the end of the environmental investigation. However, as evidenced by the Giants Ball Park project, significant time and cost savings can be realized by considering "risk management" from the outset of the project. In this sense, "risk management" represents a process of anticipating what the potential risks might be given the future use of the site, in this case a ball park, and focusing the project on evaluating and/or managing those risks. This "risk management approach" to both site investigation and remediation relies on many tools, including the use of site conceptual models to identify potential complete exposure pathways, risk-based investigations to focus data collection, deed restrictions to limit exposure pathways, and site management plans to manage identified risks. Not surprisingly, successful implementation of a risk management approach requires close cooperation between the project sponsor, regulatory agencies, and site consultant. For the Giants Ball Park site, this approach achieved site closure within 7 months of project initiation and saved an estimated $2,000,000 to $10,000,000 in investigation and remediation costs.

Volatile organic compounds (VOCs) are present in groundwater downgradient of many unlined landfills. Cover systems and gas extraction systems are often installed as remedial measures to decrease VOC concentrations. This paper examines the mechanisms by which non-aqueous phase liquids (NAPLs) placed within the waste fill may contaminate groundwater, and the potential effect of covers and gas extraction systems on these mechanisms. Field data from three case studies where covers and gas extraction systems were installed are presented. Although more data is needed to quantify the performance of these systems, three main hypotheses are presented. (1) Covers alone have a limited effect on VOC concentrations in groundwater. (2) Gas extraction systems may have spatially variable beneficial effects on VOC concentrations in groundwater. (3) The reduction of VOC concentrations due to gas extraction is likely to be a transient effect, i.e., if the gas extraction system is shut off, concentrations could rebound.

This paper discusses the technical and economic performance of three remediation projects in the form of "lessons learned." The methodology used to arrive at these lessons involved reviewing site documentation, interviewing project managers, and analyzing post-closure monitoring data. The lessons revolve around the important role that an inability to predict performance with certainty plays in decision making. We expect that these lessons will be of use to decision makers in future remediation projects, especially those employing risk-based approaches.

A preliminary (i.e., initial tier) ecological risk assessment (ERA) was conducted, as part of the RCRA Corrective Action Process at Launch Complex 37 at the Cape Canaveral Air Station (CCAS) to evaluate whether potential hazardous constituent releases could result in adverse effects to ecological resources. An uncertainty analysis was conducted as part of the ERA to assess the degree of conservatism associated with the estimated ecological hazard quotients (HQs). U.S. Environmental Protection Agency protocol was used to calculate the HQs for four terrestrial receptor species (Florida mouse, southeastern American kestrel, Florida scrub jay, and mourning dove) that could be exposed to 14 organic compounds and 8 metals identified as chemicals of potential concem (COPCs) in on-site soil. Site soil concentrations, toxicity reference values (TRVs) from the literature, and conservative assumed uptake and exposure factors were used for the HQ calculations. The uncertainty analysis included back-calculating risk-based soil screening concentrations (RBCs) from the HQs for those receptor species and corresponding COPCs for which the HQs exceeded 1. Some of the RBCs were below conservative generic soil screening criteria and below or on the order of local background levels. The uncertainty analysis indicated the high degree of uncertainty and conservative nature of the ERA results.

Brownfield transactions entail special risks beyond those encountered in typical real estate transactions. Parties negotiate heavily over the allocation of these risks. Evidence from cases suggest that risks associated with prior activities of sellers are routinely assumed by sellers. Risks associated with future regulatory activities are assumed by buyers. Parties use thinly capitalized, special purpose, limited liability entities to avoid exposure to loss in excess of invested capital. A number of govemment programs successfully reduce uncertainty associated with remediation expenditures assumed by new investors. Conventional financing for brownfields remains elusive.

The University of Tennessee's (UT) Waste Management Research and Education Institute (WMREI) has been tracking the progress of Tennessee underground storage tank (UST) site management for the past five years. Initially, this research attempted to correlate the cost of site management with selected site characteristics, such as plume size and contaminant concentration. In 1995, the Tennessee Department of Environment and Conservation (TDEC) implemented a new ranking system for sites to assign a level of risk and associated cleanup requirements. This ranking system, which scores sites based on 15 ranking score parameters, is one way in which TDEC is utilizing Risk Based Corrective Action (RBCA). As part of this phase of work, UT researchers are following the reported costs of managing a group of341 sites. Of this group, for which we have collected various site parameters, 114 are currently undergoing monitored natural attenuation (MNA), and 50 are currently undergoing active corrective action. Previously, we had looked at primary drivers behind the ranking score, which determines whether a site is allowed to undergo MNA. In this study, we show the impact of one of these parameters, the coefficient of permeability, has on determining whether a site is allowed to undergo monitored natural attenuation as a cleanup method. Also, we assess RBCA's contribution to cost reduction of UST site management.

There is a continuing debate concerning the efficiency of the Resource Conservation and Recovery Act (RCRA) corrective action process. Responsible parties and the regulatory agencies at both the state and federal levels have been at odds over the process, technology, endpoints and timing of corrective action for many years. The objective of the regulatory agencies is often remedial action to the extent technically practical whereas the objective of the responsible parties is often minimal financial expenditures for corrective action and only to the extent that there is an adverse impact to human health and the environment. These conflicting objects have resulted in a process that is tedious and time consuming and have generated considerable debate between the agency and the responsible party at individual sites. Furthermore, there are often other competing state and federal regulatory programs with different and sometimes conflicting objectives and processes. This paper discusses an alternative approach for corrective action that integrates risk assessment and risk management concepts into the corrective action process. In addition, this paper identifies the significant risk management decisions that must be resolved in order for this risk-based decision making process to be successful. The process has a role in corrective action and property environmental lifecycle management. Effective implementation of the integrated risk-based approach for corrective action will require that traditional processes, technologies and science are challenged and that an effective collaboration between responsible parties, the regulatory agencies and other stakeholders with an interest in the corrective action process is created.

BP Environmental Remediation Management (ERM) is currently responsible for corrective action for more than 1500 service station properties. BP ERM has developed a proprietary spreadsheet-based cost model to predict corrective action expenditures. These predictions are used to develop annual budgets, provide a benchmark for corrective action expenditures and to manage the environmental reserve that was established for corrective action at these sites. BP ERM has initiated a program to incorporate a risk-based decision process (RBDP) into their corrective action project management consistent with the ASTM Guide for Risk-Based Corrective Action (RBCA) for Petroleum Releases (ASTM E 1739-95). This project developed a new spreadsheet cost model for BP using a decision analysis framework to provide a basis for evaluating and predicting the cost of corrective action based on the new RBDP approach to corrective action. The model presented here provides a foundation for the analysis of future costs for corrective action under a new decision-making process. This model will assist BP corrective action project managers in evaluating sites at the tier upgrade decision. It may also prove useful in determining the value of a land use restriction during real estate sale negotiations and discussions with property buyers. The analysis presented here confirms the value of choosing the RBDP for corrective action.

An analysis of the feasibility of redeveloping residually contaminated and/or cleaned-up land (brownfields) requires estimation of the potential exposure of prospective residents of structures on such sites to residual contaminants. Candidate sites for redevelopment differ with respect to the extent of contamination, physical state of the contaminants, potential human and environmental exposure pathways and the permanence of the contaminant source. The health and environmental risk associated with using reclaimed sites has several components, some of which may not be effectively addressed by engineering measures. This paper is focused on the assessment of the key exposure parameters that can be influenced by the design, configuration and material properties of physical systems that are typically implemented at brownfield sites. Examples of engineering systems that could be used at reclaimed sites are also discussed.

This paper provides a description of the ongoing site remediation and brownfield redevelopment project at the former Koppers Seaboard Site in Kearny, New Jersey. The ongoing remediation of the site utilizing processed dredged sediments and pending redevelopment will provide the public with several benefits. First, a site to place approximately 3.44 million cubic meters of dredged sediments from the Port of New York and New Jersey will allow vital shipping to continue. Second, a large contaminated site will be remediated in part from the direct application of processed harbor sediments. Finally, the formerly fallow site will be rendered suitable for industrial use, thereby generating jobs and revenues for the local economy.

This paper details a portion of the story of how a former 173 year old urban brass mill site was transformed into a thriving new regional shopping mall. Why was this site selected? What obstacles had to be overcome? Who were the stakeholders in the process and what held them together? Who paid for the building demolition, remediation and site improvements? What were the environmental issues and how were they defined and then dealt with? How were these issues coordinated with the traditional development issues and resolved? What did we learn and where are we going with this thing we call brownfields?

A large plume of groundwater contamination was spreading beneath 2,000 acres of business and residential districts of Wichita, Kansas. The situation was worsened by the possibility of the City being listed as a Superfund site. However, an innovative approach to remediation along with close coordination with federal, state, and community governments and local property owners helped to successfully address this serious threat to public health and avert an economic crisis. The City formed a tax increment financing and redevelopment district, created a formal program to release current owners from liability and formulated agreements with lending institutions to assure loans on properties. The engineer reviewed liability release applications, helped create a cost allocation formula to support the revitalization of the affected area, and assisted in negotiating the Settlement Agreement with the State of Kansas. The unique approach to the problem resulted in the City of Wichita being awarded the Ford Foundation and the John F. Kennedy School of Government Award for Innovations in State and Local Government.

At the Gilbert-Mosley Site in Wichita, Kansas, the groundwater has been contaminated by chlorinated solvents from past industrial activities. Over 3 billion gallons of groundwater have concentrations of tetrachloroethene (PCE) and trichloroethene (TCE) above drinking water standards (maximum contaminant levels [MCLs]). The contamination covers an area of approximately 2,000 acres. The Corrective Action Decision (CAD) approved by the Kansas Department of Health and Environment (KDHE) contained several innovative items, including: (1) the cleanup criteria; (2) the approach to cleanup or the cleanup goal; and (3) the method of cleanup. First, the CAD specified a groundwater cleanup criteria or remedial action goal above the MCLs. This increase was based on a combination of evaluations, including: technical impracticability evaluations, use of institutional controls, risk assessment, and long-term monitoring. The alternate cleanup levels (ACLs) were approved as a cleanup criteria for the groundwater. The use of the higher ACLs (versus MCLs) reduced the amount of groundwater requiring cleanup by 50 percent. The second innovative item addressed in the CAD was the goal of cleanup or the approach to cleanup. Typical decisions require that contaminated groundwater that is a potential drinking water source be restored to MCLs. However, the CAD for the Gilbert-Mosley Site specified that hydraulic control of the migration of the contamination was necessary versus the typically required restoration of all contamination to drinking water standards. Finally, use of innovative technology (bioremediation) was approved in the CAD. Since finalization of the CAD, reductive iron walls, and natural attenuation have also been evaluated. Currently, data are being collected to complete intermediate designs.