Department Of Energy Sites Research Articles

Metal levels in blood, muscle and liver of water snakes (Nerodia spp.) from New Jersey, Tennessee and South Carolina

Reptiles, particularly snakes, could serve as bioindicators of contamination because some are comparatively long-lived, exhibit different trophic levels, and are at the top of their food chains. We test the null hypothesis that there are no differences in the concentrations of heavy metals in the blood, muscle and liver of water snakes (Nerodia spp.) from rivers in New Jersey, Tennessee and South Carolina. While the former site is in an urban/suburban area, the latter two sites are relatively rural and are located on Department of Energy sites. For the snakes from New Jersey, there were significant differences in metal concentrations among tissues for all metals, the highest levels for arsenic and selenium were in liver and kidney, for cadmium were in the liver, for chromium and lead were in skin, and for mercury and manganese were in the muscle. Body length was not correlated with metal levels, and there were more significant correlations for skin with internal tissues than for blood with other tissues. There were more significant correlations for mercury than for other metals. In comparing metal levels among states, levels were generally higher for snakes collected from South Carolina. These data indicate that, since water snakes accumulate contaminants differentially as a function of location, they can be useful bioindicators of environmental exposure to contaminants. Moreover, because of their wide geographical distribution and use of varying trophic compartments, this genus can be useful for cross-site comparisons.

Task- and Time-Dependent Weighting Factors in a Retrospective Exposure Assessment of Chemical Laboratory Workers

A chemical exposure assessment was conducted for a cohort mortality study of 6157 chemical laboratory workers employed between 1943 and 1998 at four Department of Energy sites in Oak Ridge, Tennessee, and Aiken, South Carolina. Previous studies of chemical laboratory workers have included members within professional societies where exposure assessment was either limited or not feasible, or chemical processing employees where laboratory and production workers were combined. Because sufficient industrial hygiene records were unavailable for all four sites, weighted duration of employment was used as a surrogate for the magnitude of exposure. Potential exposure indices were calculated for each worker using number of days employed and weighting factors for frequency of contact and year of employment. A total of 591 unique laboratory job titles indicative of a chemical laboratory worker were collapsed into 18 general job title categories. Through discussions with current and retired workers, along with examination of historical organizational charts and job descriptions, the percentage of time with activities involving the direct handling of chemicals in the laboratory was estimated for each job title category. Scaled weighting factors of 1, 0.6, 0.3, and 0.05 were assigned to the job title categories representing 100%, 60%, 30%, and 5% of daily activities handling chemicals, respectively. Based on limited industrial hygiene monitoring data, personal radiation monitoring records, and professional judgment, weighting factors that declined 4% annually were applied to each year to account for improvements in laboratory technique, advancements in instrumentation, improvement in engineering controls, and increased safety awareness through time. The study cohort was separated into three categories of chemical exposures based on department level information: (1) inorganic, (2) mixed inorganic and organic, and (3) unknown. Potential exposure indices ranged from 0.15 to 6824.5 with a median value of 377.5 and a mean equal to 884.2. This exposure assessment method is useful for epidemiologic analyses when quantitative exposure data are absent or insufficient.

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

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

Deinococcus radiodurans engineered for complete toluene degradation facilitates Cr(VI) reduction

Toluene and other fuel hydrocarbons are commonly found in association with radionuclides at numerous US Department of Energy sites, frequently occurring together with Cr(VI) and other heavy metals. In this study, the extremely radiation-resistant bacterium Deinococcus radiodurans, which naturally reduces Cr(VI) to the less mobile and less toxic Cr(III), was engineered for complete toluene degradation by cloned expression of tod and xyl genes of Pseudomonas putida. The recombinant Tod/Xyl strain showed incorporation of carbon from 14C-labelled toluene into cellular macromolecules and carbon dioxide, in the absence or presence of chronic ionizing radiation. The engineered bacteria were able to oxidize toluene under both minimal and complex nutrient conditions, and recombinant cells reduced Cr(VI) in sediment microcosms. As such, the Tod/Xyl strain could provide a model for examining the reduction of metals coupled to organic contaminant oxidation in aerobic radionuclide-contaminated sediments.

Applicability of airborne release fraction and respirable fraction values to particulate toxic chemical material releases at DOE sites

A survey of 14 Department of Energy (DOE) sites was performed to identify methodology used in the selection of airborne release fraction (ARF) and respirable fraction (RF) values for chemicals that are used to evaluate concentration exposures (i.e., consequences) for workers and public from accidental release of toxic chemical particulate material. Approximately half of the surveyed sites do not use ARF/RF values because they handle small quantities of chemicals, which are below the threshold planning quantities (TPQs) of 40 CFR 355 and threshold quantities (TQs) of 29 CFR 1910.119, where quantitative concentration (consequence) analysis is not usually performed. The sites that use ARF/RF values for chemicals typically use values that are based on DOE-HDBK-3010-94(1) that were developed for plutonium and uranium, which may not always be applicable and thus not be reliable. Guidance on ARF/RF use for toxic chemicals based on DOE-HDBK-3010-94 values is discussed in terms of density, particle size, deposition rate, and other properties.

Integrating long-term stewardship goals into the remediation process: Natural resource damages and the Department of Energy

The United States and other developed countries are faced with restoring and managing degraded ecosystems. Evaluations of the degradation of ecological resources can be used for determining ecological risk, making remediation or restoration decisions, aiding stakeholders with future land use decisions, and assessing natural resource damages. Department of Energy (DOE) lands provide a useful case study for examining degradation of ecological resources in light of past or present land uses and natural resource damage assessment (NRDA). We suggest that past site history should be incorporated into the cleanup and restoration phase to reduce the ultimate NRDA costs, and hasten resource recovery. The lands that DOE purchased over 50 years ago ranged from relatively undisturbed to heavily impacted farmland, and the impact that occurred from DOE occupation varies from regeneration of natural ecosystems (benefits) to increased exposure to several stressors (negative effects). During the time of the DOE releases, other changes occurred on the lands, including recovery from the disturbance effects of farming, grazing, and residential occupation, and the cessation of human disturbance. Thus, the injury to natural resources that occurred as a result of chemical and radiological releases occurred on top of recovery of already degraded systems. Both spatial (size and dispersion of patch types) and temporal (past/present/future land use and ecological condition) components are critical aspects of resource evaluation, restoration, and NRDA. For many DOE sites, integrating natural resource restoration with remediation to reduce or eliminate the need for NRDA could be a win–win situation for both responsible parties and natural resource trustees by eliminating costly NRDAs by both sides, and by restoring natural resources to a level that satisfies the trustees, while being cost-effective for the responsible parties. It requires integration of remediation, restoration, and end-state planning to a greater degree than is currently done at most DOE sites.

Bioreduction of Hexavalent Chromium in Flow-Through Quartz Sand Columns

Hexavalent chromium (Cr(VI)) contamination of soil and groundwater is a major environmental concern for some industrial sites and most of the U.S. Department of Energy sites. Cr(VI) is toxic and fairly mobile in groundwater. Bioreduction of Cr(VI) to less toxic and less mobile Cr(III) is considered to be a feasible option. Among the Cr(VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) has been shown to be effective in metal reduction under anaerobic conditions. Data on bioreduction of Cr(VI) by MR-1 in a flow-through soil column that better approximates the subsurface condition are not available. The objective of this research project was to study the bioreduction of Cr(VI) by MR-1 in a continuous-flow quartz sand column system. MR-1 was found to be very effective in reducing Cr(VI) to Cr(III) for concentrations ranging from 0.055 mM (2.85 mg∕L) to 0.006 mM (0.31 mg∕L) . The amount of Cr(VI) reduced prior to its breakthrough was found to be inversely proportional to its concentration in the feed du...

PRACTICAL AND SCIENTIFICALLY BASED APPROACHES FOR CLEANUP AND SITE RESTORATION

This paper presents practical and scientific approaches for cleanup and site restoration following terrorist events. Both approaches are required in actual emergency situations and are complementary. The practical examples are taken from the May 2003 second biannual national emergency exercise, Top Officials 2 (TOPOFF 2), which occurred in Chicago, Illinois, and Seattle, Washington. The scientific examples are taken from the Department of Energy sites at Rocky Flats, Fernald, and Los Alamos where cleanup initiatives based on scientific approaches and community input are underway. Three examples are provided to explain, from a practical standpoint, how decisions during the exercise had to be made quickly, even though the alternatives were not always clear. These examples illustrate how scientific approaches can be integrated into the resolution of these dilemmas. The examples are (1) use of water to wash city roads and freeways contaminated with plutonium, Am, and Cs; (2) decontamination of large public ferries that passed through a radioactive plume; and (3) handling of wastewater following decontamination within a city. Each of these situations posed the need for an immediate decision by authorities in charge, without the benefit of community input or time for an analysis of the important pathways of exposure. It is evident there is a need to merge the practical knowledge gained in emergency response with scientific knowledge learned from cleanup and site restoration. The development of some basic scientific approaches ahead of time in the form of easy-to-use tools will allow practical decisions to be made more quickly and effectively should an actual terrorist event occur.

Perspectives on chemical hazard characterization and analysis process at DOE

The United States (U.S.) Department of Energy (DOE) has a policy of Integrated Safety Management System (ISMS) that requires a hazard analysis and implementation of controls to protect the workers and public in an authorized hazard facility. The ISMS applies to all DOE facilities through DOE P 450.4, Safety Management System Policy , and DOE Acquisition Regulation (DEAR) clause 48 CFR 970.5223-1, Integration of Environment, Safety, and Health into Work Planning and Execution . However, no DOE-order or standard currently exists that provides specific guidance for the development of safety basis (SB) documentation for non-nuclear facilities. Various DOE sites over the years have adopted individual site-specific chemical SB processes and documentation resulting in wide variations across the DOE complex. The CSTC Phase 1 report, Current Chemical Hazard Characterization Practices in the DOE Complex summarizes the variations in the DOE complex (CSTC 2003-C). 1 In order to provide a common understanding of non-nuclear SB for chemical facilities, this report identifies various steps involved in developing a safety document that includes essential features of the five core steps of the ISMS. The SB development is an iterative process, but in general order of process completion, the listed steps for chemical, non-nuclear facility safety document are: • Facility and work description; • Hazard identification; • Facility hazard classification – industry Process Safety Management (PSM) based versus DOE traditional based high/moderate/low classification; • Hazard analysis – qualitative and/or semi quantitative; • Identification of controls; • Commitments to safety management programs (SMP); • Document and approval process. The non-nuclear SB process – (a) looks at different methodologies including hazard analysis from the chemical industry and DOE-STD-3009 nuclear facility-like approaches that can be used to implement each step, and (b) describes the advantages and disadvantages of various implementing methodologies that are either already in use or could be used by non-nuclear facilities. To note, this report is not a proposed standard or guidance for chemical, non-nuclear safety document. This report outlines various steps and methodologies together with advantages and disadvantages associated with them. Each DOE/NNSA facility or site can determine the appropriate course of action based on the merits and demerits of each approach. Adoption of any step of the safety document is voluntary. While intended for chemical, non-nuclear SB applications, the report may be useful in other related areas such as the emergency management program as required by DOE O 151.1C and explosive operations as required by 29 CFR 1910.109.

Perturbations, Organizational Structure, and the Measurement Problem

After an overview of theory for organizations based on data derived from individual members, we review the problem created by this traditional methodological individualism perspective and offer an alternative theory based on the mathematical physics of interdependent uncertainty for both individuals and organizations. Then a case study of the Department of Energy (DOE) and its Citizen Advisory Boards (Boards) is presented as the first application of mathematical physics to competitive heterogeneity among organizations. In contrast to the expectations of the classical perspective, but in line with our alternative theory of performance, we conclude that consensus-seeking dampens the environmental cleanup of contaminated DOE sites around the USA, while dissonance from the competition of ideas driven by truth-seeking accelerates the cleanup, improves trust, and better educates Americans in the complexities of a technical subject like radioactive waste management by dynamically aligning risk perceptions with scientifically determined risks.

Assessment of plutonium exposures for an epidemiological study of US nuclear workers

An ongoing case-control study evaluating the association between workplace external radiation exposures and leukaemia mortality required an assessment of internal plutonium exposures as a potential confounder. Of the study participants, 1,092 were employed at four Department of Energy sites where plutonium-bearing materials were processed or stored. Exposures were assessed by first categorising exposure potentials based on available bioassay data, then estimating doses for workers in the highest categories using recent recommendations of the International Commission on Radiological Protection. Given the aetiology of leukaemia, equivalent dose to active bone marrow was chosen as the exposure variable. There were 556 workers each with at least one plutonium bioassay result, assigned to one of three evaluation categories. Dose estimates were made for 115 workers resulting in a collective equivalent dose of 2.1 person-Sv for 2,822 exposure-years, compared with 29.8 person-Sv estimated from photon exposures. Modelling uncertainties were examined by comparison of results from independent analyses and by Monte Carlo simulation.

Tritium Systems Test Assembly (TSTA) Stabilization

The Los Alamos National Laboratory (LANL) Tritium Systems Test Assembly (TSTA) project was begun in 1978 to develop, design, and demonstrate the technology and safe operation of selected tritium processing systems required for a fusion reactor. In 2001, the US Department of Energy (DOE) determined that TSTA’s mission was complete and that the facility should be stabilized.At the completion of the stabilization project in 2003, TSTA was categorized as a radiological facility. Before stabilization was complete, the tritium inventory at TSTA was grouped in the following categories: tritium gas mixed with hydrogen isotopes, tritiated water absorbed on molecular sieve, tritium held up as a hydride on various metals, and tritium held up in process components. For each of these, tritium content was characterized, a path for removal was determined, and the proper disposal package was developed. Hydrogen exchange, calorimetry, direct sampling, pressure/composition/temperature, radiological smear surveys, and controlled regeneration were used to determine the tritium inventory for each category of tritium.After removal, the tritium inventory was either (1) sent to other facilities for reuse processing or (2) buried at the LANL radioactive waste disposal site. One complete experimental system was packaged and transferred to another DOE site for future use. Special burial containers were designed and fabricated for the inventory buried at the LANL radioactive waste disposal site. The project was conducted with low tritium emission to the environment and negligible personnel exposure. After the tritium removal was complete, all remaining hardware and piping were opened and vented; the facility emission was below 1 Ci per day.

Supercritical Water Oxidation of the PCB Congener 2-Chlorobiphenyl in Methanol Solutions: A Kinetic Analysis

Incineration is commonly used to destroy polychlorinated biphenyl (PCB) wastes, but this method of treatment is not ideal for all mixed liquid wastes, especially those containing radioactive materials. Therefore, other remediation technologies are needed to efficiently treat these waste forms. This study examined the supercritical water oxidation (SCWO) of 2-chlorobiphenyl (2-PCB), using hydrogen peroxide as the oxidant and methanol as a cosolvent at 2 vol %. Kinetic studies were carried out in a plug flow reactor at temperatures from 686 to 789 K and a pressure of 250 bar, with reactor residence times ranging from 1.1 to 5.8 s. Least-squares regression of the collective reaction rate data revealed that 2-PCB exhibited second-order kinetics, with an Arrhenius frequency factor, A, equal to 10(18.2+/-2.3) L x mol(-1) x s(-1) and activation energy, Ea, of 181.7 +/- 33.2 kJ/mol. The primary organic reaction products from the SCWO of 2-PCB were biphenyl at low temperatures (<700 K) and CO2 at elevated temperatures. No dioxins or chlorinated dibenzofurans were ever detected in any of the effluent samples. Additional experiments with higher organic feed concentrations (4 vol %) illustrated how the exothermic nature of the organic oxidation reactions can be used to render the process self-sustaining. Finally, SCWO destruction rates greater than 99.98% were achieved for a simulated PCB-contaminated job control waste similar to that encountered at many U.S. Department of Energy sites.

Microbial community structure and trichloroethylene degradation in groundwater

Trichloroethylene (TCE) is a prevalent contaminant of groundwater that can be cometabolically degraded by indigenous microbes. Groundwater contaminated with TCE from a US Department of Energy site in Ohio was used to characterize the site-specific impact of phenol on the indigenous bacterial community for use as a possible remedial strategy. Incubations of 14C-TCE-spiked groundwater amended with phenol showed increased TCE mineralization compared with unamended groundwater. Community structure was determined using DNA directly extracted from groundwater samples. This DNA was then analyzed by amplified ribosomal DNA restriction analysis. Unique restriction fragment length polymorphisms defined operational taxonomic units that were sequenced to determine phylogeny. DNA sequence data indicated that known TCE-degrading bacteria including relatives of Variovorax and Burkholderia were present in site water. Diversity of the amplified microbial rDNA clone library was lower in phenol-amended communities than in unamended groundwater (i.e., having Shannon-Weaver diversity indices of 2.0 and 2.2, respectively). Microbial activity was higher in phenol-amended ground water as determined by measuring the reduction of 2-(p-iodophenyl)-3(p-nitrophenyl)-5-phenyl tetrazolium chloride. Thus phenol amendments to groundwater correlated with increased TCE mineralization, a decrease in diversity of the amplified microbial rDNA clone library, and increased microbial activity.

Using Integrated Geospatial Mapping and Conceptual Site Models to Guide Risk‐Based Environmental Clean‐Up Decisions

Government and private sector organizations are increasingly turning to the use of maps and other visual models to provide a depiction of environmental hazards and the potential risks they represent to humans and ecosystems. Frequently, the graphic presentation is tailored to address a specific contaminant, its location and possible exposure pathways, and potential receptors. Its format is usually driven by the data available, choice of graphics technology, and the audience being served. A format that is effective for displaying one contaminant at one scale at one site, however, may be ineffective in accurately portraying the circumstances surrounding a different contaminant at the same site, or the same contaminant at a different site, because of limitations in available data or the graphics technology being used. This is the daunting challenge facing the U.S. Department of Energy (DOE), which is responsible for the nation's legacy wastes from nuclear weapons research, testing, and production at over 100 sites in the United States. In this article, we discuss the development and use of integrated geospatial mapping and conceptual site models to identify hazards and evaluate alternative long-term environmental clean-up strategies at DOE sites located across the United States. While the DOE probably has the greatest need for such information, the Department of Defense and other public and private responsible parties for many large and controversial National Priority List or Superfund sites would benefit from a similar approach.

Modeling reactive geochemical transport of concentrated aqueous solutions

Aqueous solutions with ionic strength larger than 1 M are usually considered concentrated aqueous solutions. These solutions can be found in some natural systems and are also industrially produced and released into accessible natural environments, and as such, they pose a big environmental problem. Concentrated aqueous solutions have unique thermodynamic and physical properties. They are usually strongly acidic or strongly alkaline, with the ionic strength possibly reaching 30 M or higher. Chemical components in such solutions are incompletely dissociated. The thermodynamic activities of both ionic and molecular species in these solutions are determined by the ionic interactions. In geological media the problem is further complicated by the interactions between the solutions and sediments and rocks. The chemical composition of concentrated aqueous solutions when migrating through the geological media may be drastically altered by these strong fluid‐rock interactions. To effectively model reactive transport of concentrated aqueous solutions, we must take into account the ionic interactions. For this purpose we substantially extended an existing reactive transport code, BIO‐CORE2D©, by incorporating a Pitzer ion interaction model to calculate the ionic activity. In the present paper, the model and two test cases of the model are briefly introduced. We also simulate a laboratory column experiment in which the leakage of highly alkaline waste fluid stored at Hanford (a U.S. Department of Energy site, located in Washington State) was studied. Our simulation captures the measured pH evolution and indicates that all the reactions controlling the pH evolution, including cation exchanges and mineral dissolution/precipitation, are coupled.

Molecular Characterization of a Dechlorinating Community Resulting from In Situ Biostimulation in a Trichloroethene-Contaminated Deep, Fractured Basalt Aquifer and Comparison to a Derivative Laboratory Culture

Sodium lactate additions to a trichloroethene (TCE) residual source area in deep, fractured basalt at a U.S. Department of Energy site have resulted in the enrichment of the indigenous microbial community, the complete dechlorination of nearly all aqueous-phase TCE to ethene, and the continued depletion of the residual source since 1999. The bacterial and archaeal consortia in groundwater obtained from the residual source were assessed by using PCR-amplified 16S rRNA genes. A clone library of bacterial amplicons was predominated by those from members of the class Clostridia (57 of 93 clones), of which a phylotype most similar to that of the homoacetogen Acetobacterium sp. strain HAAP-1 was most abundant (32 of 93 clones). The remaining Bacteria consisted of phylotypes affiliated with Sphingobacteria, Bacteroides, Spirochaetes, Mollicutes, and Proteobacteria and candidate divisions OP11 and OP3. The two proteobacterial phylotypes were most similar to those of the known dechlorinators Trichlorobacter thiogenes and Sulfurospirillum multivorans. Although not represented by the bacterial clones generated with broad-specificity bacterial primers, a Dehalococcoides-like phylotype was identified with genus-specific primers. Only four distinct phylotypes were detected in the groundwater archaeal library, including predominantly a clone affiliated with the strictly acetoclastic methanogen Methanosaeta concilii (24 of 43 clones). A mixed culture that completely dechlorinates TCE to ethene was enriched from this groundwater, and both communities were characterized by terminal restriction fragment length polymorphism (T-RFLP). According to T-RFLP, the laboratory enrichment community was less diverse overall than the groundwater community, with 22 unique phylotypes as opposed to 43 and a higher percentage of Clostridia, including the Acetobacterium population. Bioreactor archaeal structure was very similar to that of the groundwater community, suggesting that methane is generated primarily via the acetoclastic pathway, using acetate generated by lactate fermentation and acetogenesis in both systems.

The Role of Risk and Future Land Use in Cleanup Decisions at the Department of Energy

As a result of the legacy of the Cold War, the Departments of Energy and Defense are involved in massive cleanup and remediation projects. While health risk to humans and ecological receptors is perceived to be the basis for remediation, this assumption is rarely examined. In this article, we examine the role of risk and future land-use designations in cleanup decisions, using the Department of Energy's self-assessment of 36 sites. We then discuss the risk-related tools that might be required to address the cleanup challenge. Much of the current cleanup program is driven by compliance with federal and state statutes and regulations, presumably to protect human health and the environment. Compliance, however, is not synonymous with cleanup. Although some of these laws and regulations take risk into account, the lack of site-specific data on exposures and risk scenarios, and the lack of attention to future land use or end states, has often resulted in disconnects between risk and cleanup goals, risk and final end states, and cleanup levels and end state or subsequent land use. Partly, these disconnects result from the need for a range of technical, economic, sociological, and public policy tools to address the issues. A better transfer of information among and within Department of Energy facilities, operations offices, and DOE headquarters is required. Further, linking cleanup decisions and goals with the final end state involves a number of risk tradeoffs, including (1) ecological versus human health, (2) worker versus public health, (3) among competing contaminated areas, (4) among temporal patterns of cleanup, (5) among different ecological receptors (plants vs. animals, one animal vs. another), and (6) among the sites across the DOE complex. For the nation, balancing among risks is essential within sites and among Department of Energy sites, as well as among other remediation sites (such as those of Department of Defense and Superfund sites).

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Remediating Rocky Flats

In their Policy Forum “Avoiding destructive remediation at DOE sites” (12 Mar., p. [1615][1]), F. W. Whicker and colleagues applaud the “risk-based” cleanup of U.S. Department of Energy (DOE) sites and point to Rocky Flats near Denver as a success story. Unfortunately, various assumptions