Hazardous Materials in the Hydrologic Environment: The Role of Research by the U.S. Geological Survey (1996)

Efforts of the federal government to regulate toxic and hazardous materials during the past 40 years have revealed the lack of available knowledge regarding the extent and severity of hazardous material impacts on human health and the environment. It is difficult, for example, to state precisely how many potentially toxic materials are in use, how many enterprises are involved in hazardous waste management, the total volume of chemical wastes generated in the United States each year, and the total number of sites used for hazardous waste management. In addition, very little is known about the toxic effects or environmental fate of many chemicals. Thus, there are abundant research challenges in the area of hazardous materials.

The primary role of the USGS in reducing public risks associated with hazardous materials is to provide scientific support, primarily to other agencies. As the nation's leading geoscience agency, the USGS provides analyses of the fate and transport of hazardous substances through natural environments that are crucial to assessing risks and devising remediation strategies. Because the USGS is a public agency, its main responsibility is to perform research that will assist in addressing issues that are most relevant to the public interest: in the case of hazardous materials, those issues that pose the greatest risk to human health and the environment.

The federal government first became involved in the regulation of toxic and hazardous substances with the 1958 Food Additives Amendment to the Food, Drug, and Cosmetic Act. This amendment contained the

“Delaney Clause”, which prohibited the addition of a known carcinogen into human food.

In 1972, the federal government began to regulate hazardous materials that are released into the environment with the passage of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). This law authorizes the U.S. Environmental Protection Agency (EPA) to register and regulate the sale and distribution of pesticides in the United States. And although FIFRA has limited somewhat the use of pesticides, and thus has produced environmental benefits, it has also resulted in disposal problems, for example, on farms where disposal options are limited.

The Toxic Substances Control Act (TSCA), enacted in 1976, was also designed to manage releases of hazardous substances into the environment. TSCA gives EPA the authority to restrict the use of substances that are likely to present an unreasonable risk of injury to human health or to the environment. In the same year, Congress also authorized the first law regulating hazardous wastes—the Resources Conservation and Recovery Act (RCRA). Although this act was passed largely in response to the growing public awareness of serious problems related to disposal, the RCRA actually regulates the generation and transport of hazardous wastes.

The Clean Water Act of 1977 as a general pollution statute contains multiple provisions, the most relevant of which pertains to defining EPA's mission in the restoration of the physical, chemical, and biological integrity of the nation's waters. The act prescribes a list of toxic water pollutants and provides that they are subject to effluent limitations based on a “best available technology” standard, with EPA having discretion to impose more stringent limitations based on an “ample margin of safety” standard. This act, of course, has its roots in the 1948 Federal Water Pollution Control Act, the initial federal legislation regarding water quality control, which defined the federal role concerning water quality monitoring and research.

Public concern over hazardous substances increased throughout the late 1970s and early 1980s as the Love Canal incident became national news and policymakers began to confront the technical complexities of regulating these substances (Barke, 1988). EPA has estimated that U.S. industries produced approximately 290 million tons of hazardous wastes

in 1981, and that prior to RCRA, up to 90 percent of hazardous wastes was disposed of improperly (Finley and Farber, 1992).

The substantial public concern over hazardous waste disposal sites climaxed with the 1980 enactment of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, and the 1986 Superfund Reauthorization and Amendment Act (SARA). CERCLA established an information gathering and analysis system to help government agencies characterize and prioritize remediation of hazardous waste sites; it also provided the federal authority to respond to emergencies and remediate sites. The law also created a trust fund to pay for site remediation, and made parties responsible for releases of hazardous substances on lands for which they are liable. SARA requires that priority be given to remediation methods that reduce the toxicity, mobility, and volume of waste rather than trying to contain waste by transferring it to another land disposal facility. As a result of amendments to RCRA and CERCLA, there has been a move away from land disposal of hazardous wastes.

In the mid to late 1980s, following the end of the cold war, the nation began to recognize the extent of radioactive and other hazardous wastes stockpiled at Department of Defense (DOD) and Department of Energy (DOE) facilities. Potential threats to human health and the environment near these sites come not only from the millions of gallons of wastes that are currently awaiting proper disposal, but also from seriously contaminated soil, ground water and surface water, and from releases to the air. Estimated costs for remediation of these sites exceed $100 billion (World Resources Institute, 1993).

The U.S. Environmental Protection Agency began to question the high priority placed on remediation of hazardous waste sites in the late 1980s, as the agency broadened its use of scientific risk assessment. In February 1987, the EPA released a report on the relative risk of environmental problems in an attempt to set priorities for its own activities (U.S. Environmental Protection Agency, 1987). The report concluded that areas related to ground water consistently ranked medium or low in terms of the relative risk they pose to human health and the environment. The report found that active hazardous waste sites ranked relatively high in cancer risks but relatively low in non-cancer human health risks and ecological effects. These sites can also depress property

values. Overall, they were ranked medium in terms of risks to welfare. The report further concluded that RCRA sites, Superfund sites, underground storage tanks, and municipal non-hazardous waste sites were among areas of high EPA effort but relatively medium or low risk (Environmental Protection Agency, 1990).

Methods for evaluating risks posed by environmental contamination also began to change significantly in the late 1980s. Conclusions about the relative risks to human health and the environment historically have been derived from in vitro tests of toxic pollutants for acute problems such as skin rashes, eye sensitivity, and immediate mortality to test species such as fish or algae. Cancer risk also has been evaluated for many chemicals based on laboratory tests. Within the last decade, however, scientists have been accumulating more information regarding chronic effects of toxic pollutants largely from field studies of wildlife and accidental exposures of humans to organohalogens such as polychlorinated biphenyls, or PCBs (see for example, Colburn et al., 1990). These studies indicate a correlation between toxic pollutants, particularly persistent, bioaccumulative, organohalogen compounds, and teratogenic effects in humans and wildlife. More recent research has discovered that a number of synthetic chemicals, including pesticides, components in plastics and detergents, and other industrial products and by-products, are capable of disrupting the endocrine system. Humans and other organisms are exposed to these substances primarily through air, water, and ingestion.

These findings, like much of scientific research, tend to raise more questions than they answer. A substantial amount of public funds is expended on hazardous material research, regulation, and remediation. In an area of environmental management where so much uncertainty continues to exist, it is difficult, but vitally important, to set priorities for research that will be of most benefit to the public interest over the long term by assuring that remedial actions are based on sound science and that regulations are formulated and enforced in an informed manner.

The National Research Council recently described a conceptual model of the evolutionary stages of research in hydrogeology (National Research Council, 1992). Taking a process-oriented viewpoint, the report illus-

trates how research follows a well-defined pathway that leads from process discovery to process description and finally to process application. Process discovery is concerned with the original characterization of a process and often its mathematical formulation. Such a discovery may derive from experiments, field studies, or theoretical analyses. In most instances, contributions are required from all areas.

A case in point is the study of dispersion in porous media. The original studies on the process of dispersion occurred in the early 1950' s with simple column experiments and the development of the theoretical-mathematical description of the component processes. The role of dispersion at field scales remained poorly understood until the late 1970's when appropriate theoretical studies combined with subsequent large-scale field experiments were advanced. Thus, process discovery depends upon a complementary collection of research techniques involving laboratory, field, and theoretical approaches.

After a process is discovered, the thrust of research shifts to process description. This research expands the knowledge base about processes, detailing how the process works, determining its relative importance to other processes, and establishing values for characteristic parameters of the process. The main investigative approaches involve carefully controlled field and laboratory experiments, and sensitivity analyses with mathematical models. Returning again to the study of dispersion, examples of research on process discovery include the many laboratory experi-experiments designed to establish “characteristic” values of dispersion lengths for different types of media, and field studies to quantify correlation structures that give rise to macro-scale dispersion.

After a process and its controlling parameters are well understood, it is possible to utilize this knowledge to solve practical problems through process application. For example, after discovering the ability of indigenous populations of microbes to biodegrade some organic contaminants, and describing the conditions under which these processes occur, it is possible to focus on the development of related remedial methodologies.

The conceptual model described above portrays how research in process-oriented hydrology should proceed, and serves as a basis for this report. The remainder of this report examines the state-of-the-art of research in areas related to hazardous materials science and technology, explains how the USGS is presently positioned for this research, and

explains how the USGS is presently positioned for this research, and describes opportunities for the USGS in addressing critical needs in these areas.

The character of scientific research has changed with time. For instance, from relatively humble beginnings in the 1920's, 1930's, and 1940's, hydrology has developed into a complex science embodying elements of physics, chemistry, mathematics, and biology. The research categorization methodology developed in the previous section can be used as a measure of research progress in the study of flow and mass transport processes. In general, as fundamental problems are solved and experience is gained, the research emphasis logically shifts to applications. For example, such is the case with ground water flow through saturated media. After over 100 years of research, the continuing focus in the area of saturated flow is mainly to develop flow codes (e.g., MODFLOW; McDonald and Harbaugh, 1988), or computational enhancements to codes (e.g., Hill, 1990). The study of coupled flow processes (complex problems where, for example, mass transport depends upon fluid flow and fluid flow depends upon mass transport), however, remains at the process discovery stage and will require extensive research to sort out a large array of complex effects.

The emphasis on research related to problems of hazardous waste will almost certainly shift toward applications. What remains to be discussed is what ultimately brings about this shift to applications, and when it is likely to occur in the various process areas. Analysis of these questions should be useful in planning future USGS research efforts on hazardous materials science and technology.

The WRD of the USGS has a number of programs in which studies are conducted to aid in resolving problems related to the contamination of surface and ground waters by hazardous materials (see Appendix A). Funding for projects related to hazardous materials in various programs within the USGS has reflected priorities established both by the USGS and by Congress (Figure 2.1).

FIGURE 2.1 Expenditures on USGS programs related to hazardous materials: Federal-State Cooperative Program, Toxic Substances Hydrology Program, Low-Level Nuclear Waste Hydrology Program, Department of Defense Environmental Contamination Program.

Note: The values for the Federal-State Cooperative Program are estimated by assuming that approximately 14 percent of the total Federal-State budget, the future reported by Gilbert et al. (1987) for FY 1986, is devoted to contaminant-related work.

Funding for the Federal-State Cooperative Program for projects on hazardous materials has increased fairly substantially, although in terms of constant dollars, the funding for the program has been essentially flat. Funding for the Toxic Substances Program, by the same reasoning, has decreased slightly in constant dollars. Funding for the Nuclear Waste Hydrology Program declined to zero in 1994. In addition to programs funded internally by the USGS, other federal agencies also fund work related to hazardous materials that is performed by USGS personnel. In recent years, work in support of environmental restoration and waste management at Department of Defense (DOD) sites has increased drammatically. Over the past eight years, the relative contribution of the various major programs has shifted somewhat, with an increase in the percent of the work funded other federal agencies being related to growth in work related to hazardous materials (Figure 2.2).

Within and across USGS programs related to hazardous materials science and technology, there is a spectrum of activities that ranges from pure research to what may be called service—the problem-solving function of the Water Resources Division within government. Separating research from service is not an easy task. Langbein (1981) addressed this question by starting with Webster's definition of research “(1) careful or diligent search (2) studious inquiry or examination esp....having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories or laws, ...or the practical application of such new or revised conclusions, theories, or laws.” He pointed out that with a definition as broad as (1), virtually every program of the USGS, including data collection, would constitute “research ”. He preferred instead the more narrow definition implied in (2), which he interpreted to mean new techniques, instruments, and exploration (Langbein, 1981).

By this latter definition, research constitutes a relatively small proportion of the activities of the Water Resources Division. Activities related to hazardous materials science and technology that concentrate almost exclusively on research are found mainly in the Toxic Substances Hydrology Program, which involves researchers in USGS district offices and the national centers. In addition, core funding for the National Research Program (NRP) contributes significantly to the overall research effort in hazardous materials science and technology. There are also

FIGURE 2.2 Breakdown of funding by major source of funds: Federal appropriations, state and local government contributions to lthe Federal-State Cooperative Program, and reimbursements from Other Federal Agencies.

Source: Data for FY 1986 from Gilbert et al. (1987). Data for FY1994 from material provided by G. Mallard, USGS, Reston, VA.

many projects under the Federal-State Cooperative Program that have a substantial research component. NAWQA, which has a small research component, also provides opportunities for integration of research from other USGS programs within the framework of issues of national concern.

In this study, the research and service activities of the USGS have been differentiated in order to concentrate primarily on research. It is recognized that the service functions can and do contribute to research, but a more intensive focus on the issue of research per se was chosen.

Hazardous material and toxic waste research in the United States is conducted by a variety of organizations including universities, federal and state government agencies, and large and small corporations. Historically, the type of research each has conducted has been framed by a variety of factors, such as the mission of the organization, history, and circumstance. Federal agencies with missions related to regulating hazardous materials (e.g., EPA) or with extensive remediation problems at agency sites (e.g., DOD, DOE) have a perspective toward research strongly oriented toward short-term results. The USGS is one of the few federal agencies with a more long-term view, having a broad program in field-oriented, multidisciplinary research in hazardous materials science as related to problems in the natural environment. The USGS is known throughout the world for its experience in monitoring the natural environment and for the collection of high-quality, consistent data sets. The USGS is particularly well versed in taking an integrated approach to the study of systems and for including the important details regarding temporal and spatial variability in characterizing natural constituents.

Universities, by virtue of the discontinuous funding they receive for research and the relatively more limited infrastructure, typically restrict their research to aspects of process discovery. Much of the work involves computer simulation or laboratory experimentation. Field-related hazardous material remediation studies, when they are undertaken, often require strong support from organizations like the USGS, ARS, or the DOE that have ongoing field operations. Some programs have been able to fund field research at high levels from a variety of funding sources, but this is the exception rather than the rule.

Programs of the USGS related to hazardous materials science and technology are dominated by field studies that have as their goal the discovery and description of surface and ground water flow and mass transport processes. This focus is understandable, given the historical roots of research within the Water Resources Division, and the distributed character of the organization where many researchers work in district offices. The USGS is one of a very few organizations among all of the

groups (universities, other federal agencies, and states) that has the ability to conduct long-term research in field settings.

EPA, DOD, and DOE focus much of their research efforts on applications owing to their cleanup responsibilities. These agencies have large and active programs concerned with developing new remedial strategies for the cleanup of hazardous and mixed wastes. Much of this research has a strong engineering orientation directly related to waste (ex situ and in situ waste treatment). All three agencies support fundamental process studies through their large extramural grant programs and their own laboratories. Research and development work in industry is mainly concerned with the commercialization of new remedial processes and the development of new measurement processes. The research and development work being performed is tied closely to practice.

Interestingly, the focus of research also can be influenced by the nature of the reward system. For example, excellence in research at the discovery end of the spectrum often is “measured” by papers published in high quality scientific journals that stress innovation in research. Relatively little attention is paid to whether the research is “ industrially relevant”. At the applications end of the spectrum, success is measured by patents, licenses, and commercialization. In many cases, research is presented in the scientific literature for reasons other than to advance science.

This discussion raises important questions concerning the future direction of research related to hazardous materials. For example, are there reasons why the USGS or any of the other organizations should reallocate their activities differently across the research sub-divisions—discovery, description and application? Are there factors that would favor one given research topic over another?

Clearly, the assessment of what research will be most important in the next decade depends upon the selection of rational criteria that might serve to identify critical research. To a large extent, the “consumer” of the research determines the prioritization of research foci or areas. Some organizations, like the National Science Foundation, are responsive to national and international needs and initiate research in critical areas such as “Global Change and Continental Hydrology ” and “Math and Science Education”. Another large body of research consumers is represented by industrial hydrogeologists. To this group, critical research is that with the

potential to affect the practice of hydrogeology. It is more difficult to support research programs in the area of process discovery and term them as critical. However, programs such as the “solvents in ground water program” at the University of Waterloo, and the “microbial processes program” and the “passive bioremediation program” developed within the USGS under the leadership of Derek Lovely and Mary Jo Baedecker, respectively, are examples of successful research.

Another, slightly different consumer of critical research is the organization that is conducting the research. For example, critical research for AT&T or IBM is that research that has the potential to develop new products within the organization. Critical research at the USGS might involve research that creates opportunities for technological leadership or increases the effectiveness of its district efforts. Critical research also may advance specific goals or missions of the agency, or the public and political perception of what the agency mission is all about.

To date, individual researchers within the hazardous waste programs bear the major responsibility for determining the direction and focus of future studies. In many respects, such an approach provides the academic freedom of a university researcher with the added benefit of at least some assured funding. This emphasis on curiosity-driven research has served both the USGS and individuals well in the past. It could be argued that political and economic realities have eclipsed this research model, however. The major corporations cited above all have restructured their research programs in fundamental ways that emphasize corporate needs for research and development. For example, although some may lament the passing of the “old” Bell Laboratories as the premier basic research organization of its kind in the world, AT&T has adapted to the realities of the market place.

The Toxic Substances Hydrology Program has developed and flourished as a curiosity-driven research program that has capitalized on the particular abilities of the USGS to conduct large-scale interdisciplinary field studies. Nevertheless, there are important ways in which the Toxic Substances Program must evolve to ensure that the work of the USGS is focused on work of highest importance to the nation. First, more of the work must be made immediately relevant to the major cleanup issues that the country is presently facing at industrial and defense facilities. The report's recommendations in the areas of remedial technologies provide

an overview of how to address this problem. Second, complementary laboratory and modeling studies must be used to support and to generalize field investigations, which have been the focus of much of the work to date.

As pointed out above, the research programs of the USGS related to hazardous materials are focused on studies of surface and ground water flow and mass transport processes. The endpoints for this research —the applications—are: 1) the analysis of water resources and of sites as to their suitability for waste disposal; 2) the analysis of contaminated resources and sites to evaluate the need for cleanup and to determine effective strategies for cleanup; and 3) the provision of unbiased information to guide legislation and governmental policy decisions. These are topics of critical concern to the nation. Conservative estimates of the cost of cleaning up contaminated sites in the United States are very large. Considering only ground water and soil remediation, and considering only DOE sites, estimated costs over the next three decades are several hundreds of billions of dollars (National Research Council, 1994c). When surface waters, wetlands, and sediments are included and attention is not focused solely on DOE, it is clear that solutions to the problems associated with hazardous materials in the environment are both costly and daunting.

Potentially toxic chemicals are now present, at least in trace quantities, essentially everywhere. For example, polychlorinated biphenyls (PCBs), DDT, dioxins, hexachlorocyclohexane (HCH), dibenzofurans, chlordane, and toxaphene have been found in arctic air, surface water, snow, suspended sediments, fish, marine mammals, seabirds, terrestrial animals and humans (Barrie et al., 1992; Lockhart et al., 1992; Muir et al., 1992; O'Connor et al., 1992; Thomas et al., 1992). The nearly ubiquitous nature of hazardous materials presents two key challenges to those involved in research on hazardous materials in the environment: defining the major problems (with regard to risk to human health and

ecosystem functioning) and determining practical alternatives for alleviating the problems.

A broad range of problems involving the contamination of water resources affect the United States. Surface waters, including streams, rivers, wetlands, lakes, reservoirs, and estuaries, are contaminated with organics, metals, nutrients, and sediments. Sources of the contamination range from industrial discharges to agricultural runoff to direct deposition from the atmosphere. Because many of the contaminants that are released into surface waters partition onto sediments, there are also significant problems associated with hazardous materials in deposits of sediments in waterways and wetland areas. A recent NRC report (National Research Council, 1990a) summarizes some of the problems related to contamination of surface waters and sediments, and provides recommendations for restoration of these aquatic systems.

Ironically, laws passed between 1952 and 1977 to control air and water pollution caused many industries and municipalities to turn to land disposal for wastes, an action that has contributed to some of the most difficult problems of ground water and soil contamination now faced. Estimates of the number of contaminated sites in the United States range in the hundreds of thousands, with a variety of contaminants present in the soils and ground waters. Some of the issues related to hazardous substances in ground water are addressed in a recent NRC report (National Research Council, 1994a).

The long-term outlook for environmental cleanup at contaminated sites is not clear. Nor are all of the requisite tools available to determine in a cost-effective manner when natural processes will suffice, i.e., when “passive” or “intrinsic” remediation will be adequate to protect humans and ecosystems in the final analysis. Moreover, the scientific understanding and methods needed to assess the appropriateness of a given site as a waste-disposal facility are not all yet available.

The strength of the USGS has been in areas of geoscience: in collecting data that allow assessment of the quality of water, in gaining a fundamental understanding of what natural processes are important in the transport of contaminants (including biogeochemical reactions), and in developing models that are useful in analyzing contaminant transport in natural systems. Building on these strengths, the USGS should pursue a strategy in the area of hazardous materials science and technology that

stresses: 1) improvements in the ability to characterize natural environments in terms of the transport of contaminants and of the biogeochemical reactions that affect these contaminants (i.e., gaining an understanding of the nature of different environments, including processes that affect contaminants); 2) improvements in methods for remediating contaminated sites (i.e., gaining an understanding of the processes and techniques that are useful for containing and for cleaning up contaminated sites); and 3) improvements in the way information gained from scientific studies can be used to reach decisions about appropriate actions in cases where cleanup is likely to be difficult and costly. It is in these areas that the USGS can make important contributions toward solving the problems associated with remediation of contaminated sites and with protection of the environment, especially with regard to proposed new waste-disposal sites. Some of these issues are explored in the remainder of this report.