Using the National Land Cover Database as an indicator of shrub-steppe habitat: comparing two large United States federal lands with surrounding regions.

There is a need to assess whether ecological resources are being protected on large, federal lands. The aim of this study was to present a methodology which consistently and transparently determines whether two large Department of Energy (U.S.

The importance of recognizing Buffer Zones to lands being developed, restored, or remediated: on planning for protection of ecological resources.

Environmental management relies on many types of information before making decisions regarding remediation, restoration, or other land use decisions, including ecological data, such as risks to species, populations, communities, and ecosystems. The aim of this investigation was to describe the ecological information required within the context of making environmental decisions and providing visual communication tools for regulators, conservationists, and the public to understand the risk to ecological resources on- and off-site. It is suggested that ecological information used in environmental decisions is required to be transparent throughout the planning and execution of a project, which needs to include: 1) ecological information and evaluations within development areas or units (in this case, watersheds), and 2) resources in adjacent areas (Buffer Zones) that might be affected.

Comparing land cover and interior forests on contaminated land and the surrounding region: Oak Ridge Reservation as a case study.

Pressure from expanding populations has resulted in a need for protection, reclamation, and restoration of damaged land to productive, beneficial health uses. The objective of this investigation was to 1) compare land cover on the Department of Energy (DOE) Oak Ridge Reservation (ORR) with the surrounding region, 2) select an indicator to evaluate ORR's protection of ecological resources, and 3) develop and implement a method to compare the amount of the indicator on ORR with the regions using National Land Cover Database (NLCD). Data demonstrated that ORR has a higher % of forests (deciduous, coniferous, mixed) than the 10 km and 30 km areas surrounding ORR, suggesting that obligations are being met to protect the ecology and environment.

Evaluating the impact of drying on leaching from a solidified/stabilized waste using a monolithic diffusion model.

The release rates of constituents of potential concern from solidified/stabilized cementitious waste forms are potentially impacted by drying, which, however, is not well understood. This study aimed to identify the impacts of drying on subsequent leaching from Cast Stone as an example of a solidified cementitious waste form. The release fluxes of constituents from monoliths after aging under 100, 68, 40, and 15 % relative humidity for 16, 32, and 48 weeks, respectively, were derived from mass transfer tank leaching tests following EPA Method 1315.

Impact of oxidation and carbonation on the release rates of iodine, selenium, technetium, and nitrogen from a cementitious waste form.

Evaluation of the long-term retention mechanisms and potential release rates for the primary constituents of potential concern (COPCs) (i.e., Tc, I, Se, and nitrate) is necessary to determine if Cast Stone, a radioactive waste form, can meet performance objectives under near-surface disposal scenarios.

Application and uncertainty of a geochemical speciation model for predicting oxyanion leaching from coal fly ash under different controlling mechanisms.

Three primary mechanisms (adsorption to iron oxides or analogous surfaces, co-precipitation with Ca, and substitution in ettringite) controlling oxyanion retention in coal fly ashes (CFAs) were identified by differentiating the leaching behavior of As, B, Cr, Mo, Se, and V from 30 CFAs. Fidelity evaluation of geochemical speciation modeling focused on six reference CFAs representing a range of CFA compositions, whereby different leaching-controlling mechanisms of oxyanions were systematically considered. For three reference CFAs with low Ca and S content, calibration of adsorption reactions for the diffuse double-layer model for hydrous ferric oxides improved the simultaneous prediction of oxyanion leaching, which reduced uncertainties in Se and V predictions caused by nonideal adsorption surfaces and competitive adsorption effects.

Impact of carbonation on leaching of constituents from a cementitious waste form for treatment of low activity waste at the DOE Hanford site.

Carbonation can be a major aging process during disposal of alkaline cementitious waste forms and can impact constituent leaching by changes in material alkalinity, pore structure, and controlling mineral phases. The effect of carbonation on the leaching of major and trace constituents from Cast Stone, a cementitious waste form developed to treat high salt content low activity waste, was studied through a combination of leaching experiments and reactive transport simulations. Diffusive transport of constituents in the waste form was evaluated using reactive transport modeling of diffusion-controlled leaching test results and a geochemical speciation model derived from pH-dependent leaching.

Combining ecological, eco-cultural, and environmental justice parameters to create Eco-EJ indicators to monitor cultural and environmental justices for diverse communities around contaminated sites.

Assessing environmental quality often requires selection of indicators that can be employed over large spatial scales and over long-time periods to assess the health and well-being of species, natural communities, and ecosystems, and to detect changes warranting intervention. Typically, the ecologic environment and the human environment are evaluated separately and selection of indicators and monitoring approaches are not integrated even though ecological indicators may also provide information on risk to human consumers from contaminants (e.g.

The influence of redox conditions on aqueous-solid partitioning of arsenic and selenium in a closed coal ash impoundment.

A closed coal ash impoundment case study characterized the effects of field redox conditions on arsenic and selenium partitioning through monitoring of porewater and subsurface gas in conjunction with geochemical speciation modeling. When disposed coal ash materials and porewater were recovered for testing, oxidation led to lower arsenic and higher selenium concentrations in leaching test extracts compared to porewater measurements. Multiple lines of evidence suggest multiple mechanisms of arsenic retention are plausible and the concurrent presence of several redox processes and conditions (e.

Development of a Geochemical Speciation Model for Use in Evaluating Leaching from a Cementitious Radioactive Waste Form.

Cast Stone has been developed to immobilize a fraction of radioactive waste at the Hanford Site; however, constituents of potential concern (COPCs) can be released when in contact with water during disposal. Herein, a representative mineral and parameter set for geochemical speciation modeling was developed for Cast Stone aged in inert and oxic environments, to simulate leaching concentrations of major and trace constituents. The geochemical speciation model was verified using a monolithic diffusion model in conjunction with independent monolithic diffusion test results.

Demonstration of the use of test results from the Leaching Environmental Assessment Framework (LEAF) to develop screening-level leaching assessments.

Environmental management often benefits from leaching assessment as a predictive tool for estimating constituent leaching from solid and waste materials. The Leaching Environmental Assessment Framework (LEAF) provides both validated tests methods for characterizing materials and a methodology for developing screening assessments based on material characterization results. The use of LEAF data in a screening-level environmental assessment approach is demonstrated through a hypothetical case study of copper/lead smelter soil remediation.

Methodology for scenario-based assessments and demonstration of treatment effectiveness using the Leaching Environmental Assessment Framework (LEAF).

A methodology for developing scenario-based leaching assessments as part of the Leaching Environmental Assessment Framework (LEAF) is illustrated using a hypothetical management/treatment scenario of contaminated soil from a copper and lead smelter. Scenario assessments refine the process beyond screening-level assessments by considering site- and scenario-specific information about the disposal or utilization environment. LEAF assessments assume (i) granular materials leach at local equilibrium with percolating water, while (ii) monolithic materials (e.

Risk to ecological resources following remediation can be due mainly to increased resource value of successful restoration: A case study from the Department of Energy's Hanford Site.

Many nations are faced with the need to remediate large contaminated sites following World War II, the Cold War, and abandoned industrial sites, and to return them to productive land uses. In the United States, the Department of Energy (DOE) has the largest cleanup challenge, and its Hanford Site in the state of Washington has the most extensive and most expensive cleanup task. Ideally, the risk to ecological resources on remediation sites is evaluated before, during, and after remediation, and the risk from, or damage to, ecological resources from contaminants should be lower following remediation.

A paradigm for protecting ecological resources following remediation as a function of future land use designations: a case study for the Department of Energy's Hanford Site.

Since the late 1980s, there has been a US federal mandate to clean up contaminated sites remaining from the Second World War, the Cold War, and abandoned industries. One determinant of cleanup standards for remediation is future land use-how will the land be used and by whom? Land use decisions may be consensus documents developed by site owners, state and federal agencies, and local stakeholders. Often there are competing views and/or claims on how remediated sites should be used, including as open or green space.

Evaluation of ecological resources at operating facilities at contaminated sites: The Department of Energy's Hanford Site as a case study.

The U.S. and other developed nations are faced with many contaminated sites remaining from World War II, the Cold War, and abandoned industries, that require remediation and restoration to allow future land uses with minimum acceptable risk to humans and ecological resources.

The costs of delaying remediation on human, ecological, and eco-cultural resources: Considerations for the Department of Energy: A methodological framework.

Remediation and restoration of the Nation's nuclear legacy of radiological and chemical contaminated areas is an ongoing and costly challenge for the U.S. Department of Energy (DOE).