Stalking the RCRA leapfrog

In the preceding article, “RCRA Leapfrog: How Statistics Shape and in Turn Are Shaped by Regulatory Mandates,” Dr. Kirk Cameron expressed his opinion on how the RCRA statistical program had developed into its current state, focusing on interactions that have occurred between regulators, geologists, regulated individuals, and a small group of professional statisticians over the past 10 to 15 years. Here, Dr. Robert Gibbons, a member of that small group, responds to some of Dr. Cameron's comments.     

Understanding the RCRA corrective action process

The Resource Conservation and Recovery Act (RCRA) was enacted in 1976. The Hazardous and Solid Waste Amendments (HSWA) of 1984 specify “corrective action” requirements for protecting human health and the environment from environmental contamination at active hazardous waste treatment, storage, and disposal facilities. RCRA and its corrective action requirements are designed to prevent the creation of new Superfund sites by regulating and remediating active facilities. The RCRA corrective action process has four basic components: the facility assessment, facility investigation, corrective measures study, and corrective measures implementation. This article presents an overview of the RCRA corrective action process and presents four case studies from three U.S. EPA regions.     

Understanding and Managing Indoor Air Exposure Assessments at RCRA Sites

The 2000 RCRA National Conference was conducted August 15‐17, 2000, in Washington, D.C., to allow state and federal authorities to review regulatory issues associated with the Resource Conservation and Recovery Act (RCRA) program. One of the RCRA reform issues discussed at the conference included the Government Performance and Results Act (GPRA) Environmental Indicators (EI). EIs have been designed to provide clarity in cleanup objectives and spur progress towards meeting the U.S. Environmental Protection Agency's (USEPA's) national RCRA cleanup goals. This article focuses on the human exposure indicator and, more specifically, on indoor air exposures and how to assess whether such exposure is actually occurring. While indoor air exposure can be a critical component of the human exposure scenarios, realistic predictions of the exposures are difficult to produce. This article provides an overview of the regulatory issues related to the indoor air exposure pathway. It also discusses the use of modeling in criteria development and risk evaluation and presents a case study of how the USEPA wants the modeling to occur, and an opinion of where this RCRA reform issue is heading and how to evaluate indoor air exposures.     

Monitoring parameters and statistics: A land treatment unit monitoring case study

Statistical evaluation procedures for monitoring data at facilities permitted under the Resource Conservation and Recovery Act (RCRA) are frequently established before monitoring begins. Selecting the statistical method before background data have been collected often leads to the use of statistical procedures that are inappropriate for the actual monitoring data. Such was the case for unsaturated zone monitoring at a permitted land treatment unit in the Gulf Coast area of Texas. Due to the large number of “not detected” results in the background database for lysimeters, statistical evaluation procedures specified in the original RCRA permit yielded an artificially low standard deviation, resulting in background values that were strongly biased on the low side. An alternate statistical procedure based on probability plots was developed and was accepted by the state environmental regulatory agency. This technique, which has wide applicability for many types of environmental monitoring data, significantly reduced the chasing of false positives, thus saving potentially expensive investigations and remediations.     

Influences on RCRA corrective action costs for nonfederal facilities

Thousands of known hazardous waste sites across the country require remediation, with thousands more yet to be discovered, at estimated cleanup costs of billions of dollars over the next few decades. With this enormous financial burden placed on all members of society through increased prices, taxes, and lost investment opportunities, policy makers face the difficult prospect of defining cleanup standards that meet the goals of protecting human health and the environment and achieving remediation in the most cost-effective manner. Using a statistical methodology to investigate factors influencing the cost of RCRA corrective action, this article examines site characteristics that significantly affect cleanup costs and explains differences in costs among EPA's four proposed Subpart S corrective action options.     

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.     

RCRA corrective action costs: An estimating model for nonfederal facilities

This article presents an analysis of the prospective costs of RCRA corrective action for private, nonfederal facilities. Two data bases developed by Research Triangle Institute and a remedial action cost model developed by CH2M Hill provide the foundation for this work. The methodology has two components, a remedial action knowledge base and a discrete-state Monte Carlo analysis. Under base case assumptions, it is estimated that the total costs of RCRA corrective action will be $240 billion, with a 5 percent chance the costs will be less than $170 billion and a 5 percent chance the costs will be more than $377 billion.     

Underwater treatment of lead-contaminated sediment

The sediment associated with the reconstruction of a bridge pier was classifiable as hazardous by the Toxicity Characteristic Leaching Procedure (TCLP), due to elevated concentrations of lead. However, RCRA regulations do not classify the sediment as hazardous unless it is moved. RMT designed an in-situ, underwater treatment process to render the sediment nonhazardous, using phosphate-based chemistry before dredging. Subsequent sediment management was conducted without the additional regulatory requirements and costs associated with managing hazardous waste.     

Treatment of remediation wastes in RCRA corrective action management units

This article explains new EPA regulations that provide for use of corrective action management units (CAMUs) and temporary units (TUs) as cost-effective techniques for remediating hazardous wastes at facilities undergoing RCRA corrective action and at CERCLA remediation sites. The author outlines EPA criteria for approving the use of CAMUs, discusses the benefits and limitations of using them, and recommends possible ways to improve on the CAMU concept.     

Translating a remediation technology into the required air,water, and rcra permits

Because remediation techniques and technologies are themselves generally viewed as contaminant source by hazardous waste laws and regulations, permits are required to use them, even if it is only to contain or remove a site's principal contaminants. Referring to such major environmental laws as the Clean Air Act, the Clean Water Act, RCRA, TSCA, and CERCLA, this article outlines the steps needed to translate cleanup projects into the appropriate permits.     

Choosing the most effective hazardous waste landfill cover

Determining the appropriate criteria and designs for hazardous waste landfill covers has spawned much discussion within the environmental remediation arena. Very little reliable comparison of various technologies exists. Researchers at Los Alamos National Laboratory studied the relative hydrologic performance of four landfill cover designs—two capillary barrier designs, one modified EPA RCRA design, and one control cover. Monitoring the fate of natural precipitation for nearly four years showed that the covers with barrier layers more effectively reduced deep percolation than the control cover. Although none entirely eliminated deep percolation, the RCRA cover, incorporating a clay hydraulic barrier, most effectively controlled it. The two capillary barriers reduced deep percolation, but significant amounts were still produced. Over 90 percent of all percolation through the covers, and lateral flow within the covers, occurred during February through May each year, primarily as a result of snowmelt, early spring rains, and low evapotranspiration. The study also showed that gravel mulch surface treatments (70- to 80-percent ground cover) reduced runoff and erosion. Despite additional shrubs planted on one, the two plots receiving the gravel mulch treatments exhibited equally enhanced amounts of evapotranspiration.     

Field testing of particulate matter continuous emission monitors at the DOE Oak Ridge TSCA incinerator. Toxic Substances Control Act

A field study to evaluate the performance of three commercially available particulate matter (PM) continuous emission monitors (CEMs) was conducted in 1999-2000 at the US Department of Energy (DOE) Toxic Substances Control Act (TSCA) Incinerator. This study offers unique features that are believed to enhance the collective US experience with PM CEMs. The TSCA Incinerator is permitted to treat PCB-contaminated RCRA hazardous low-level radioactive wastes. The air pollution control system utilizes MACT control technology and is comprised of a rapid quench, venturi scrubber, packed bed scrubber, and two ionizing wet scrubbers in series, which create a saturated flue gas that must be conditioned by the CEMs prior to measurement. The incinerator routinely treats a wide variety of wastes including high and low BTU organic liquids, aqueous, and solid wastes. The various possible combinations for treating liquid and solid wastes may present a challenge in establishing a single, acceptable correlation relationship for individual CEMs. The effect of low-level radioactive material present in the waste is a unique site-specific factor not evaluated in previous tests. The three systems chosen for evaluation were two beta gauge devices and a light scattering device. The performance of the CEMs was evaluated using the requirements in draft Environmental Protection Agency (EPA) Performance Specification 11 (PS11) and Procedure 2. The results of Reference Method 5i stack tests for establishing statistical correlations between the reference method data and the CEMs responses are discussed.     

Hazardous chemical site remediation through capping: Problems with long-term protection

The capping of waste management units and contaminated soils is receiving increasing attention as a low-cost method for hazardous chemical site remediation. Capping is used to prevent further groundwater pollution by existing waste management units and contaminated soils through limiting the moisture that enters the wastes. In principle, for wastes located above the water table, the construction of an impermeable cap can prevent leaching of the wastes (leachate generation) and groundwater pollution. In practice, appropriately designed and constructed RCRA caps can provide for only short-term prevention of groundwater pollution. Alternative approaches are available for capping of wastes that can be effective in preventing moisture from entering the wastes and concomitant groundwater pollution. These approaches recognize the inability of the typical RCRA cap to keep wastes dry for as long as waste constituents will be a threat and, most importantly, provide the necessary funds to effectively address all plausible worst-case scenario failures that could occur at a capped waste management unit or contaminated soil area.     

Risk assessment and accepted regulatory cleanup levels

The determination of cleanup levels at a CERCLA or RCRA site is often the single most important decision made by risk managers. This decision can have a major impact on the costs and time required for remediation, as well as on the selection of remedial technologies. The object of this article is to provide a critical review of the methods used by regulatory agencies and the regulated community to calculate chemical-specific cleanup goals for inactive hazardous waste sites, focusing on those cleanup goals that are designed to protect human health from the effects of chemicals. In addition to this analysis of historical methods that have been used, this article discusses some innovative solutions to the problem of calculating cleanup levels and presents an analysis of controversial topics related to cleanup levels currently under debate by regulatory agencies, industry, environmentalists, and legislative bodies.     

How changing regulations determine biotreatment options for petroleum wastes

Remediation of refinery wastes is regulated by three major federal environmental statutes: the Clean Air Act, the Clean Water Act, and the Resource Conservation and Recovery Act (RCRA); other statutes apply, but to a lesser degree. During the past two years, RCRA's rules have effectively outlawed the passive biological treatment of primary refinery waste sludges in waste ponds and lagoons, even though the law recommends active biological treatment as the second stage in the waste treatment train. RCRA's land disposal restrictions may also outlaw land farming treatment for the bottom sludges involved in crude oil storage. Since 1980, when the U.S. Environmental Protection Agency listed an initial group of five waste streams as hazardous, the agency has listed two more waste streams and twenty-five organic constituents, several found in petroleum wastes. Now it is about to list fourteen more petroleum refining wastes and is studying the addition of fifteen more waste streams. Treatment standards and restrictions have also been promulgated. This article explores the biotreatment techniques and technologies that are still available to petroleum and environmental engineers.     

Proven methods for managing public perception of cleanups

Negative public perceptions can dramatically increase site remediation costs or even bring projects to a grinding halt. Public opposition and ensuing political pressure are two damaging, but often ignored, obstacles that confront remediation managers. This article discusses these and other public management issues, recommending tactics proven for maintaining positive working relationships with a site's human neighbors, the media (electronic and print), government officials, regulatory agencies, and other concerned groups to allow site cleanup to proceed without intervention, opposition, or unnecessary delay. It illustrates its warnings about public and political hostility with case histories from Superfund, RCRA, and other cleanup sites, recounting how corporate management won the public's confidence and kept their projects on time and within budget.     

Primer on GRITS/STAT 5.0

GRITS/STAT 4.2 (Groundwater Information Tracking System with statistical analysis capability) enjoys widespread use in the groundwater community. GRITS/STAT is a free PC-based database system capable of performing many of the statistical methods promulgated by the EPA guidance documents: Statistical Analysis of Ground-Water Monitoring Data at RCRA Facilities, 1989, and Addendum to Interim Final Guidance, 1992. GRITS/STAT 4.2, however, suffered from numerous software problems and lagged behind current guidance, particularly in the implementation of statistical intervals. With the release of GRITS/STAT 5.0, many of the software problems that plagued GRITS/STAT 4.2 were addressed and an entirely new Statistical Intervals module was added to bring the software closer to current guidance. The GRITS/STAT 5.0 Beta Test produced a helpful list of work arounds to commonly reported problems. A comparison of the Parametric Confidence Interval methods in GRITS/STAT 4.2 and GRITS/STAT 5.0 illustrates the expanded utility offered by the new Statistics module. The Parametric Confidence Interval in GRITS/STAT 4.2 is only moderately useful for comparing individual wells to an alternate concentration limit (ACL) computed on average background samples. GRITS/STAT 5.0, however, offers users the ability to compare individual and pooled wells to ACLs computed on background averages and risk-based maximum concentration limits (MCLs).     

An overview of the US EPA’s multiple pathway exposure methodology

The US Environmental Protection Agency’s National Center for Environmental Assessment is finalizing its updated approach to assessing the health risks from direct and indirect exposure to combustion emissions. The prior 1990 Indirect Exposure Methodology has been used frequently in the early part of this decade, while the new methodology considers more pathways for agent transfer and exposure. This advanced methodology is not limited to exposure from combustion emissions as the approach lends itself to assessing indirect exposure to other agents in various exposure scenarios. The purpose of this presentation is to alert the user community to the new methodology and discuss its impacts on risk assessment. A brief overview of the exposure pathways, along with the inherent uncertainties of the MPE and the risk characterization, are presented. Other associated documentation is presented and referenced. The paper concludes with a discussion of the planned implementation of the MPE and the Agency program guidance for use with RCRA combustor permitting and risk assessments.