A Novel Mobile Examination and Remediation Facility for On-Site Remediation of Dry Storage Systems
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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
Several 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. In this paper, we report the risk to ecological resources before, during, and as a consequence of remediation on contaminated units requiring cleanup, and then examine the causes for changes in risk by evaluating 56 cleanup evaluation units (EUs) at the Hanford Site. In this case, remediation includes a restoration phase. In general, the risk to ecological and eco-cultural resources is currently not discernible or low at most contaminated units, increases during remediation, and decreases thereafter. Remediation often causes physical disruption to ecosystems as it reduces the risk from exposure to contaminants. Most new remediation projects at the Hanford Site include ecological restoration. Ecological restoration results in the potential for the presence of higher quality resources after remediation than currently exists on these contaminated lands and facilities. Although counter-intuitive, our evaluation of the risk to ecological resources following remediation indicated that a significant percentage of units (61%) will be at increased risk in the post-remediation period. This increased risk is due to DOE's successful remediation and restoration that results in a higher percent of native vegetation and higher ecological value on the sites in the post-remediation period than before. These newly-created resources can then be at risk from post-remediation activities. Risks to these new higher quality resources include the potential for spread of invasive species and of noxious grasses used in previous cleanup actions, disruption of ecosystems (including those with state or federally listed species and unique ecosystems), compaction of soil, use of pesticides to control invasive species, and the eventual need for continued monitoring activities. Thus, by greatly improving the existing habitat and health of eco-receptors, and maintaining habitat corridors between high quality habitats, the ecological resources in the post-remediated units are at risk unless care is taken to protect them. Many of the negative effects of both remediation and future monitoring (or other future land uses) can be avoided by planning and management early in the remediation process. We suggest DOE and other agencies convene a panel of managers, remediation scientists, regulators, environmental and ecological scientists, Native Americans, economists, and the public to develop a generic list of performance metrics for the restoration phase of remediation, including evaluation of success, which could be applied across the DOE complex.
54 ENVIRONMENTAL SCIENCES↗
SURF: Advances in the Incorporation of Sustainability Into Remedial Approaches - 16451
The inclusion of sustainability considerations in remediation cleanup process (investigation through site closure) benefits site owners, including Federal agencies such as the Department of Defense (DOD) and Department of Energy (DOE), through development of more efficient and cost-effective remedies as well as communities by considering socio-economic impacts and redevelopment into remedial decisions. The incorporation of social, environmental, and economic considerations early in the remedial process often enables achievement of regulatory site closure sooner and with broader community acceptance. In order to achieve these objectives, stakeholders, including federal facilities, regulators, contractors, and consultants, have expressed the need for case studies demonstrating successful implementation of sustainable practices. The Sustainable Remediation Forum emerged in 2006 and was established as a non-profit organization in 2010. Through exploration of technical issues such as groundwater conservation and reuse at remediation sites to life cycle assessment approaches, subject matter experts have led discussions across the industry of how the incorporation of sustainability into the remediation process can provide benefits through: - Consideration of socioeconomic impacts and drivers for remediation and redevelopment; - Reduced environmental impacts of remedial actions; and - Enhanced economic value through partnerships and informed decision making. Incorporation of sustainable remediation concepts provides distinct and recognizable value, as demonstrated through the technical initiatives of the Sustainable Remediation Forum, remediation industry conferences and events, and the prevalence of government agency and corporate sustainable remediation programs, such as the DOE's Cross-Programmatic Work Group. Sustainable remediation has evolved from discussions of environmental impacts of cleanups (with considerable green-washing), to quantifying and minimizing the environmental footprint and subsequent long term global impacts of a remedy, and currently, incorporating strategies to address all three components of sustainability - environmental, social, and economic. However, the practice of sustainability must continue to advance and new approaches should be adopted to holistically evaluate beneficial and detrimental impacts from the remedial process and incorporate sustainability concepts throughout the project life cycle. A more holistic and comprehensive approach, beyond the traditional paradigm of sustainable remediation, will lead a project team to achieve social and economic sustainability objectives of the community while protecting human health and the environment. This 'advanced' approach is where the most significant benefits will be achieved. Practitioners need documented, peer-reviewed, technically sound concepts and examples of sustainable remediation as supporting material to gain acceptance and approval of incorporation of best management practices and evaluation techniques. Reviewing the advancements of sustainable remediation over the last 5-10 years and the identification of lessons learned has great merit. This discussion of case studies will highlight successful incorporation of social impacts, economic analysis, and site redevelopment into the remedial process to provide a roadmap for site owners in developing sustainable approaches for their sites. Specifically, benefits were achieved in these case studies through promotion of economic development, innovative financing, incorporation of risk-based approaches, and consideration of social value of a site. (authors)
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Remediation Technologies Screening Report for the Deep Vadose Zone, Hanford's Central Plateau - 12414
Deep Vadose Zone contamination is a significant issue because it represents a potential source for continued release of contamination to the groundwater and associated receptors. This contamination, which is the result of past waste disposal practices on the Hanford Site Central Plateau, occurs deep in the subsurface and is not easily remediated by typical surface remedies. The Deep Vadose Zone is defined as the sediment below the limit of typical surface-based remedies (such as, excavation or caps), but above the water table. The Central Plateau Deep Vadose Zone begins at a depth of approximately 15 m (50 ft) below ground surface and extends to a depth of approximately 76 m (250 ft) below ground surface. Cleanup of the Deep Vadose Zone is challenging because contamination is difficult to access and expensive to characterize; contaminants occur at different depths and soil types; conventional, surface-based remedies have limited effectiveness; and remedy performance is difficult to predict, test, and monitor. Typically, remedial technologies for Deep Vadose Zone contamination are less developed than for the shallow soil contamination or saturated groundwater contaminants. In addition, few remediation technologies have been tested in the field, and fewer still have been successfully implemented as full remedial actions. These challenges, along with the limited number of potentially applicable remediation technologies, complicate the decision-making process for evaluating and selecting Deep Vadose Zone remedial alternatives. The Deep Vadose Zone remediation technologies pre-screening involved a comprehensive review of potentially applicable technologies for remediating Deep Vadose Zone contamination in the Hanford Site's Central Plateau. The list of remediation technologies was developed from previous Hanford Site studies, science and technology databases, as well as other cleanup projects across the country that have similar conditions. The list of remediation technologies was shared with the public and stakeholders to provide an opportunity to identify additional technologies. From these efforts, 59 technologies that may support future remediation of the Deep Vadose Zone were identified. The initial list of 59 potential technologies were then screened in order to identify viable or potentially viable technologies whose implementation would benefit from further investigation and evaluation during the remedial investigation/feasibility study activities. This approach eliminated five technologies from further consideration because they either would not be ready to support remediation within the next 3 to 5 years or were not applicable for Deep Vadose Zone remediation. Eleven (11) technologies were identified as viable, requiring no further testing or investigation during the RCRA Facility Investigation/Remedial Investigation activities. The remaining 43 potentially applicable technologies were identified as requiring additional testing or investigation to determine whether they should be considered further in the selection of a remedial alternative for the 200-DV-1 Operable Unit. The results of this pre-screening effort will be used to plan and scope the appropriate field investigation, treatability study, and feasibility study tasks during development of the 200-DV-1 Operable Unit Work Plan. (authors)
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Integrated program for department of energy environmental management office of soil and groundwater remediation - 15426
The subsurface problems that remain at the U.S. Department of Energy (DOE) Office of Environmental Management (EM) sites are technically complex and the costs to complete the cleanup mission are expected to range from $17 billion to $21 billion. There is growing recognition that conventional remedies will not meet regulatory goals at a number of sites and alternative approaches will be required. To address the challenge, the EM Office of Soil and Groundwater Remediation created an integrated program to develop innovative scientific and technical in conjunction with engagement of stakeholders, regulators, and the public. The integrated program provides a holistic approach to assess the risk associated with the remaining challenges facing EM and develop solutions that achieve remediation goals and protect human health and the environment. The integrated program uses a systems-based framework for achieving environmental remediation goals. The framework is based on developing and updating a site conceptual model and includes steps to 1) provide the technical basis for remedial actions, 2) assessments of potential remedies, and 3) implementation and management of remedies to achieve site restoration goals. The Office of Soil and Groundwater remediation defines research and development needed to successfully define and apply the framework. Research opportunities and targets are identified in characterization and conceptual model development, predictions of site conditions, remediation, monitoring, and remediation decision support. Characterization and quantification of key subsurface uncertainties is needed to support conceptual model development, identify contaminant source zones, quantify the flux of contaminants from source terms to points of compliance, and characterize controlling processes for remediation approaches including natural attenuation. Predictive analyses are needed to support development of remediation endpoints, select and design active and in situ or passive remedies, assess remedy performance, and predict long-term contaminant behavior for design of monitoring systems. Advancements are needed to support adaptive remediation approaches and to develop long-term contaminant management strategies for complex sites, such as effective in situ treatment methods for long-lived contaminants ({sup 99}Tc, {sup 129}I, U, Hg, etc.). Monitoring tools and approaches are needed to evaluate remedy performance and plume behavior and decision support methods are needed to quantitatively evaluate remediation alternatives. The Office of Soil and Groundwater Remediation leverages scientific understanding provided through partnerships with the DOE Office of Science, the Department of Defense, and Environmental Protection Agency. These partnerships are helping EM develop scientific understanding and technologies for implementing the assessment framework. (authors)
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Sustainable Remediation of Radionuclides By a Common Sense Approach to Enhanced Attenuation - 16441
Development of in situ and relatively passive remedies for treatment of groundwater contaminated by metals and radionuclides is becoming more important because of the difficulty and cost - both to the environment and financially -- of removing these types of contaminants from the subsurface by pump-and-treat or excavation. In situ technologies rely on reactions that tend to remove contaminants from groundwater by partitioning them to solid phases in the aquifer. Monitored natural attenuation (MNA) relies solely on natural reactions to achieve remedial goals. Enhanced attenuation (EA) uses engineered approaches to supplement remediation when MNA is not sufficient to meet remedial goals. Both approaches leave contaminants in the subsurface and require a high burden of proof that contaminants will not be mobilized and become a risk in the future. Proof of the sustained effectiveness of an EA remedy is made much easier by strategic design. In multi-contaminant plumes, it is important to prioritize contaminants according to the risk they pose, with the recognition that one remedy rarely treats all contaminants. The goal for the engineered portion of the remedy should be maximum risk reduction with minimal engineering. Natural attenuation or negotiated alternate concentration levels will often allow low risk contaminants to go untreated. Whenever possible, the remedy should be consistent with the geochemical evolution of the waste site, insuring that the treated immobilized contaminants are likely to remain relatively immobile for long time frames. Finally, use what nature provides geologically, hydrologically, geochemically, or microbiologically in the remedy design. One of the impediments faced by waste site managers in implementing EA remedies is paralysis by perceived complexity. There are things that must be known to design an effective EA remedy, but there is always the temptation to know everything to eliminate the possibility of failure. Furthermore, there are plenty of people warning of failure if all is not known and they are usually willing to help the design team know all, for a price. Yet, the price of trying to eliminate all risk is never implementing an innovative remedy. All parties involved -- scientists/engineers, waste site managers, regulators and stakeholders must assume some degree of risk to deploy an EA remedy. If all parties are to assume some risk, then trust built through close communication from the start is required. The U.S. Department of Energy Office of Environmental Management has funded an applied field research initiative for several years focused, in part, on developing EA remedies for metals and radionuclides using these guiding principles. This approach to EA remedies grew out of developing and deploying a remediation strategy to replace a pump-and-treat system at the F-Area Seepage Basins on the Savannah River Site. The pump-and-treat system was energy intensive, produced several thousand cubic feet of solid radioactive waste per year, and cost $ 1 million per month to operate. The EA remedy that replaced the pump-and-treat is energy efficient, produces no waste, and costs approximately $1 million per year to maintain. At the F-Area Seepage Basins approximately 7 billion liters of low level radioactive waste solutions were disposed in three unlined basins resulting in contaminated groundwater containing various radionuclides and other contaminants. The primary contaminants of concern are tritium, strontium-90, uranium, and iodine-129. Other key features of the contaminant plume are its acidic nature with pH values as low as 3.2, its vertical stratification in the water table aquifer, and the tendency of the most contaminated portions to follow troughs in the top of the clay separating the upper aquifer zone from the lower aquifer zone. The geology was exploited by installing a funnel-and-gate system into the clay with the barrier portion blocking contaminant flow paths in the troughs in the clay. This forces the most contaminated water to flow through the gates where it encounters an in situ treatment zone created by periodic injections of alkaline solution. The flux of tritium has been reduced significantly by the barrier walls. Strontium-90 and uranium are treated by enhanced sorption in the circum-neutral pH treatment zone, consistent with natural geochemical evolution of the waste site from acidic to more neutral pH. An additional in situ treatment zone was created up-gradient of the one of the gates to treat iodine-129. Sub-micrometer diameter silver chloride particles were injected into the aquifer by direct push methods to create the treatment zone. In the laboratory and in a field pilot test the poorly soluble silver chloride particles reacted with iodide to form much less soluble silver iodide. Evaluation of the effectiveness of the silver chloride is ongoing. (authors)
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Guidance for Monitoring Passive Groundwater Remedies Over Extended Time Scales
Passive remediation can be appropriate where natural processes and actions such as institutional controls mitigate exposure to contaminated groundwater, achieving remedial action objectives and protectiveness of human health and the environment. Monitored natural attenuation (MNA) is a prevalent passive remediation strategy supported by a regulatory framework and monitoring design guidance. However, long-term passive remedies are usually selected in combination with at least one active remedy, such as source removal, in situ treatment, or pump-and-treat, functioning as a complementary method for achieving remediation objectives and meeting the applicable statutory and regulatory requirements. However, MNA and existing monitoring guidance primarily target situations where the remedial action objectives are met within a few decades. When time scales for passive remediation extend to many decades (50 years or more), a corresponding change in monitoring strategy is needed to adapt to the extended time scale. This document provides guidance for implementing an extended-scale monitoring (ESM) approach appropriate for long-duration passive remediation. Extended-scale is defined in this document with respect to time (i.e., a long duration of remediation) and a large enough physical scale such that downstream receptors will not be impacted within the remediation timeframe. ESM applies to slow-moving groundwater contaminant plumes and emphasizes monitoring primarily for potential exposure pathways. For this approach, the primary monitoring objective is to demonstrate that the plume diminishes before reaching the receptor zone or point of compliance and/or a receptor does not receive concentrations above the compliance limit. While the overall objectives of protecting human health and the environment are the same as for plumes where remediation can occur over a shorter time period, the time scales between decisions are longer and the dynamics of plume evolution are slower. To this end, a scenario-based strategy is described for different plume and source conditions, defining a containment and receptor zones. The containment zone is the area where the risk of exposure to groundwater contamination can be mitigated (e.g., through institutional controls) during the remediation time period. The receptor zone is defined as the area where exposure to groundwater contamination cannot be mitigated and compliance concentration standards must be met. Within the containment zone, slow plume migration may occur, leading to concentrations that exceed compliance standards. However, where distance to the receptor zone is large relative to plume migration and attenuation rate, this approach can be protective of the receptor zone. Selection of a long-duration passive remedy needs to be based on sufficient understanding of contaminant sources, hydrogeology, and contaminant plumes. A strong technical basis, supported by predictive analysis, is recommended to substantiate that contamination is expected to stay within the containment zone during the active remediation and attainment phase of the remedy, and diminish to meet compliance standards within the extended timeframe prior to reaching the receptor zone (e.g., many decades or even centuries). The ESM approach is based on verification of plume behavior and not on detailed plume dynamics. Monitoring is conducted to confirm expected behavior with an emphasis on exposure pathways to verify that plumes remain contained in areas where the protectiveness objectives can be met. ESM should not be adopted if there is significant risk of the plume extending beyond the containment zone. Given the slow movement within the containment zone, less frequent sampling is required relative to approaches used for conventional-scale remediation.
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An Overview of Nanomaterials for Environmental Remediation Applications
The environmental remediation capabilities of nanoparticles were reviewed and evaluated. Nanoparticles (NPs) have been used to remediate various forms of environmental contamination. Various materials, morphologies, and conditions are required to remediate different contaminants. Nanoparticles may have benefits and/or limitations compared with traditional remediation methods. New techniques are being applied to mitigate the limitations of NPs. Nanomaterials are a promising technology for the environmental remediation. NPs have been used for the remediation of aqueous and atmospheric contaminants. Nanoparticles have been used to sequester contaminants toxic to human and environmental health. Various materials, morphologies, and conditions are necessary for the remediation of different contaminants. The remediation of heavy metals is of significant concern. Contaminants may be remediated by means of sorption or reduction. The remediation capability of nanoparticles is promising due to their high surface area and reactivity. Reaction kinetics are, therefore, notably fast. These characteristics make NPs attractive for environmental remediation. Various NPs have been used as sequestering agents for environmental contaminants. NPs have been used to remediate heavy metals as well as organic contaminants. Technical Objectives: Assess viability of nanoparticles (NPs) for environmental remediation; Review benefits and limitations of NPs; Design future experiments to test remediation capabilities of NPs. Future Plans: Create NP filters for remediation - Grow Au NPs on Stainless Steel Wool: Stainless steel wool has many defects and crevices allowing the Au NPs to grow on the surface; Stainless steel wool will not react with the heavy metal contaminants tested; NPs are embedded, so they do not have to be removed from solution. Test sorption capabilities with heavy metal contaminants in aqueous solution. Benefits of Gold NPs: Corrosion/oxidation resistant; Exhibit visible/near IR plasmon resonance; Can be synthesized by solution chemistry: cost efficient and easily scalable. Surfactants: Used to lower surface energy and prevent aggregation; Sodium citrate: anionic surfactant (-); Cetyltrimethylammonium bromide (CTAB): cationic surfactant (+); Ionic surfactants create charged NPs; Charged NPs can be used to sequester ionic contaminants (eg. heavy metals)
54 ENVIRONMENTAL SCIENCES↗
GIS-Based Modeling of Contaminated Soil Volumes at Multiple Sites in the Formerly Utilized Sites Remedial Action Program - 20149
The remediation of hazardous, toxic, and radioactive waste (HTRW) sites produces cost-related risks associated with the estimation of contaminated soil or debris volumes. Historical risk-management techniques include cost contingencies to cover volume uncertainties that affect project budgeting and decision-making. The Buffalo District teamed with project partners to lessen volume uncertainty and reduce project risks at multiple HTRW sites managed under the Formerly Utilized Sites Remedial Action Program (FUSRAP). Historical remedial investigations under FUSRAP commonly identified the presence of radiological material in site media, the associated human health risk, and then areas of remediation. To manage remedial execution and reduce risk, pre-design or remediation-phase sampling essentially 'chased' contamination, which was not conducive to efficient predictive budgeting derived from Feasibility Study (FS) cost analyses. The Buffalo District first optimized their approach to better understand volume uncertainty by utilizing the Argonne National Laboratory's Bayesian Approaches for Adaptive Spatial Sampling (BAASS) software [1]. BAASS processed soft data (e.g., gamma walk-over data) and spatial sampling data to estimate the lateral extent of contaminated soil irrespective of depth (i.e., gross contamination extent) and define areas of contaminant uncertainty. The software performed a binary transformation of contaminant concentrations at all sampling points based upon remedial action goals or a sum of ratios approach (i.e., clean, impacted, or range of impacts in soil). The model produced two-dimensional (horizontal) contaminant probability contours and statistical uncertainty in the sampling coverage and resulting contaminant extents. This method was translated vertically by partitioning the sampling data into depth brackets that produced a stacked representation of contaminant extents and uncertainty in the subsurface (i.e., similar to construction lifts). The results commonly led to a better understanding of project uncertainty and the need for sampling strategies that produce high-confidence soil volumes, which control costs. The BAASS-based delineations were eventually replaced by Empirical Bayesian Kriging (EBK) methods available in ArcGIS Spatial or 3D Analysts [2]. The EBK method calculates contaminant probability zones derived from user-controlled semivariograms of the spatial datasets. The resulting probability zones (e.g., 50% or 80% of contaminant probability) represent the two-dimensional surface delineation of the overall horizontal remedial area, similarly to BAASS. However, unlike BAASS, the vertical sampling data within these probability zones became vertical control points to contour a subterranean surface that connects subsurface points to the land-surface delineations of contamination. The resulting representation of horizontal and vertical impacts within an enclosed envelop (volume) of soil included uncertainty distributions that are used to plan uncertainty-reduction sampling. These data-driven and math-based models of three-dimensional sampling results produced well-bounded remedial volumes for project planning and better uncertainty predictions during project budgeting. The EBK method was applied to several FUSRAP sites managed by the Buffalo District and compared to less rigorously modeled sites previously remediated by the District. The comparison of modeled to actual remediated volumes provide a basis for validating the volume-estimation method. This comparison is important to ensure modeled volumes match physical boundaries of site remediation. FUSRAP sites with denser investigative sampling and lesser volume uncertainty proved useful in remedial planning and contracting. The Buffalo District noted that historical sites with sparser sampling arrays had greater disparity between estimated volumes and final remedial volumes. The benefit achieved over the cost of detailed soil sampling appears positive for FUSRAP projects, especially where impacts vary widely and appear unbounded by investigation-phase sampling. The subsequent Empirical Bayesian Kriging of contamination coupled with vertical contouring for soil estimations reduces uncertainty in soil volumes or indicates where sampling is required to reduce uncertainty, which together optimize remedial planning and budgeting. (authors)
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Opportunities to Implement Solutions to Achieve Remedial Action Objectives in Consideration of Stakeholder Interests - 20365
A case study in the implementation of a soils excavation and removal project conducted at a Formerly Utilized Sites Remedial Action Program (FUSRAP) Maywood Superfund Site (FMSS) vicinity property; an active commercial business, in a densely populated area, with significant operational, technical and, logistical constraints that were expected to limit areas that could be remediated. The United States Army Corps of Engineers-led (USACE) team successfully navigated complex overlapping stakeholder interests to achieve a more efficient and complete removal of contaminated soils and debris while minimizing unnecessary excess costs to the Government. This paper centers on FUSRAP activities at the FMSS vicinity property located at 149-151 Maywood Avenue, Maywood, Bergen County, New Jersey. For most of its FUSRAP history, this ∼109,000 square meter (27-acre) property housed a now-demolished ∼26,000 square meter (6.5-acre) warehouse operated by Sears Logistics Services, a unit of the Sears Roebuck Company (Figure 2). Sears ended its property lease and vacated the warehouse in December 2016. Given that long history and for the purposes of this paper, the property will be referred to as the 'Sears property' or simply 'the property.' The Sears property is approximately 109,000 square meters (27-acres) and is currently zoned for commercial use. The property is bound to the north and northwest by 100 West Hunter Avenue (the Stepan Company), to the northeast by 205 Maywood Avenue, to the east by Maywood Avenue, to the south by 23 West Howcroft Road, and to the west by businesses on NJ Route 17 and the NJ Route 17 roadway. Until December 2016, the property housed a warehouse and distribution center operated by Sears Logistical Services. On-site structures were demolished by the property owner in 2017. The warehouse covered the north section of the property along the Stepan Company property line. A railroad spur from the adjacent property now known as the Maywood Interim Storage Site (MISS) ended at the northeast corner of the warehouse. Wetlands were located east of the warehouse; the rest of the property was covered with paved parking lots and grassed areas. During remediation at the property, opportunities frequently arose where the project team was able to coordinate effectively with stakeholders to sequence remediation activities to facilitate removal of otherwise inaccessible soils and identify opportunities for materials reuse when supported by residual radiological and chemical levels. Some specific opportunities include: - remediating individual truck loading dock bays to maintain tenant operations; - working along a busy highway and in a utility corridor containing a 30-inch high pressure gas main; - remediating Lodi Brook and associated wetlands requiring bypass pumping and other diversionary structures to maintain local community stormwater drainage; - protecting during remediation and supporting access to facilitate tenant/owner maintenance of critical fire protection and water supply system service lines buried in contaminated soils and necessary for safe warehouse operations; and - coordinating with stakeholders to ensure non-radiological contaminants of concern for the site (unaffiliated with FUSRAP) were addressed by the responsible party in a manner that maximized benefit to all parties while supporting an efficient overall site remediation program. Once the property was vacant and the warehouse structure and radiologically non-impacted above-grade structures were demolished, the project identified an opportunity to significantly reduce the volume of waste associated with the foundation of the former warehouse, a foundation suspected of being partially constructed in radiologically contaminated soils. The project developed and implemented supplemental radiological verification survey and sampling strategies based on radiological cross-contamination risk potential with process flow-charts and screening-level based decision points; a program that classified saw-cut sections of concrete based on observed residual surface radioactivity conditions using a combination of gamma sensitive sodium-iodide scans and beta sensitive Geiger-Muller direct measurements. The proposed approach was reviewed with stakeholders with feedback, including consideration of applicable State of New Jersey Site Remediation Program criteria and guidance before implementation. Once classified, additional sampling was performed at frequencies driven by screening. The sampling methods, stockpile sampling frequencies, criteria and, approach to data evaluation were developed in consideration of existing site cleanup standards, regional background ranges, State of New Jersey radiological remediation program guidance, and specific stakeholder input With the property remediation and survey efforts nearly completed, it is relevant to examine retrospectively the objectives, assumptions and limitations in the remedial design (i.e., what was planned) versus what was able to be accomplished through effective teaming. Benefits to other environmental remediation site programs include better understanding of how to work effectively with stakeholders to achieve win-win outcomes, and approaches to site remediation, waste minimization and materials reuse that were successful in their overall outcomes. (authors)
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The phyto-remediation of radioactively contaminated land - a feasible approach or just bananas?
Soil is an essential component of all terrestrial ecosystems and is under increasing threat from human activity. Techniques available for removing radioactive contamination from soil and aquatic substrates are limited and often costly to implement; particularly over large areas. Frequently, bulk soil removal, with its attendant consequences, is a significant component of the majority of contamination incidents. Alternative techniques capable of removing contamination or exposure pathways without damaging or removing the soil are therefore of significant interest. An increasing number of old nuclear facilities are entering 'care and maintenance', with significant ground contamination issues. Phyto-remediation - the use of plants' natural metabolic processes to remediate contaminated sites is one possible solution. Its key mechanisms include phyto-extraction and phyto-stabilisation. These are analogues of existing remedial techniques. Further, phyto-remediation can improve soil quality and stability and restore functionality. Information on the application of phyto-remediation in the nuclear industry is widely distributed over an extended period of time and sources. It is therefore difficult to quickly and effectively identify which plants would be most suitable for phyto-remediation on a site by site basis. In response, a phyto-remediation tool has been developed to address this issue. Existing research and case studies were reviewed to understand the mechanisms of phyto-remediation, its effectiveness and the benefits and limitations of implementation. The potential for cost recovery from a phyto-remediation system is also briefly considered. An overview of this information is provided here. From this data, a set of matrices was developed to guide potential users through the plant selection process. The matrices take the user through a preliminary screening process to determine whether the contamination present at their site is amenable to phyto-remediation, and to give a rough indication as to what plants might be suitable. The second two allow the user to target specific plant species that would be most likely to successfully establish based on prevailing site conditions. The outcome of this study is a phyto-remediation tool that can facilitate the development of phyto-remediation projects, avoiding the need for in-depth research to identify optimal plant species on a case-by-case basis. (authors)
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Sustainability Index for Comparison of Environmental Remediation Technologies - 17492
Site remediation is a multi-decade process that incorporations planning from a variety of parties including stakeholders, regulators, scientists and engineers, and community members. When Best Management Practices are integrated during remediation action at sites, there are significant improvements to a variety of metrics including economic, environmental, and societal factors. Green and sustainable remediation tools are Best Management Practices that are a valuable means to reduce or remove environmental footprints after remedial action at sites. Applying the analysis to future feasibility studies, EM takes the next steps towards being a leader in global sustainability. The sustainability index is a quantitative test in response to a recent study published by scientists at the Hanford Site detailing an exit strategy for pump and treat remediation technologies in an effort to move away from active remediation in favor of passive techniques. The sustainability index attempts to quantify the relative sustainability of active and passive remediation strategies by examining a variety of metrics and perspectives from those involved in the decision-making process. Analysis compared 10 metrics encompassing environmental, social, and economic aspects of sustainability for the two types of remediation techniques. Perspectives and values of the stakeholders, regulators, scientists and engineers, and community members involved the decision-making process were also incorporated in this tool. Data were evaluated from active and passive remediation technologies at two locations (Richland, Washington and Mound, Ohio). Data suggest passive remediation technologies performed better in terms of sustainability performance than active technologies. Switching from active remediation to passive remediation techniques has the following impacts: aids in the conservation of local ecosystems, reduces community impacts and improves the community perception of the cleanup, lowers the lifecycle cost of the project, and contributes positively to global sustainability by using less energy and raw materials. (authors)
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Integration of Local Knowledge is a Key for the Remediation Success of Legacy Uranium Mine Sites - 19564
A key to success, during all aspects of the remediation process on legacy uranium sites, and easily transferable between countries and projects, is the integration of local knowledge. However, before this knowledge can be integrated, local trust and project understanding must be developed. Local trust and project understanding can only be developed through a principle-centred approach to a shared project vision, two-way communication of knowledge, alignment of project goals, and understanding the local needs early in the remediation process. Once public confidence is obtained, local trust and project understanding must be maintained throughout the entirety of the remediation process. Project understanding is an ongoing endeavor that needs continuous communication and varied methods to succeed. During the management of assessment, remediation, and post remediation monitoring on the Saskatchewan Research Council's CLEANS project (remediation of 37 legacy uranium mine sites in Northern Saskatchewan, Canada), integration of local knowledge has been an instrumental tool attributing to success. During site assessment, integration of local knowledge has included the development and implementation of land use surveys to determine realistic travel and occupancy on and adjacent to these legacy sites, and site specific traditional knowledge and land use studies that have contributed to the development of a detailed knowledge of local land use, resource utilization, country food intake, and human history of the sites. The local knowledge gained during the assessment process is invaluable as it provides information required to support remediation planning, such as: valued ecosystem components, human trophic utilization, length of site occupancy, cultural value assessment, and future land use considerations. During remediation planning, local and traditional knowledge can also be incorporated through determination of plant species suitability for revegetation, development and selection of remediation options, and setting realistic sustainable development targets for local project inclusion. During site remediation operations, local involvement can be utilized through direct labour and equipment, cultural resource monitoring (i.e. archaeological and heritage protection), local logistics and historic information transfer, and stakeholder communications and engagement support. Post remediation, local involvement is an efficient mechanism for long-term monitoring, and care and maintenance activities. Although there may be differences between countries, regions and sites, the remediation process on legacy uranium mines can universally be more successful through the integration of local knowledge; while developing rights/stakeholder engagement and capacity building. (authors)
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Constraints in the Remediation of Uranium Former Uranium Mining Sites - 19586
Uranium mining and milling legacy sites still exist all over the world. Financial constraints play a key role in constraining the remediation of these sites, but a series of other factors must also be considered. The IAEA has been assisting its Member States in moving forward their remediation projects, and more specifically the Central Asian region has received dedicated attention in this aspect. In association with other international organisations such as the European Commission and European Bank of Reconstruction and Development among others in the scope of the CGULS initiative (Coordination Group of Uranium Legacy Sites), a series of activities have been put in place to assist the countries in that region. Through its Technical Cooperation Department, the IAEA has also supported other Member States to manage their legacies. The IAEA CIDER Project (Constraints in Decommissioning and Environmental Remediation) in its first phase investigated possible constraint to implementation of both decommissioning and environmental remediation projects, and collected successful experiences and lessons learned from remediation projects all over the world. It started with a survey in which almost 30 Member States participated. Constraints were examined in three main areas: i) Institutional Aspects (regulatory and policy); ii) Technological and iii) Social. These results have been published in a dedicated report available in the IAEA web page (also called the CIDER Baseline Report). Under the request of participating Member States, a second phase of CIDER has been initiated with a more focused (action oriented) character. In this regard experts developed a framework for helping countries in need under two major areas: Strategy Development and Implementation and Stakeholder Engagement Support. Two other initiatives under CIDER Phase II consisted of the Enhanced Capacity Building in Environmental Remediation (the so-called School of Environmental Remediation) and a database depicting the sites in and in need of remediation in a global perspective. This paper is intended to present and promote some aspects of the methodology conceived in CIDER Phase II to help countries establish remediation strategies that will facilitate overcoming some of the barriers mentioned above. Furthermore, it aims to discuss aspects that might be improved in the assistance provided by international organisations to countries in need of developing remediation projects, pointing out to some of the documented causes for not achieving more robust results. It is expected that the combination of different tools to share good practices e.g. web-based tools, e-Learning, webinars in addition to face-to-face training events, may enhance the chances of successful implementation of remediation of legacy sites, including former uranium production sites. This initiative opens a wide avenue for cooperation while providing a platform to bring together practitioners, regulators, contractors, funding organisations to enhance the support to be provided. By working together, more effective and sustainable results can be achieved and remediation of such sites implemented in a timely, safe and cost-effective way. (authors)
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Remediation of Uranium Impacted Sediments in a Watercourse - 12486
In 2009, remediation was initiated for a non-operational fuel cycle facility previously used for government contract work. Between 2009 and the spring of 2011, remediation efforts were focused on demolition of contaminated buildings and removal of contaminated soil. In the late spring of 2011, the last phase of remediation commenced involving the removal of contaminated sediments from portions of a 1,200 meter long gaining stream. Planning and preparation for remediation of the stream began in 2009 with submittal of permit applications to undertake construction activities in a wetland area. The permitting process was lengthy and involved securing permits from multiple agencies. However, early and frequent communication with stakeholders played an integral role in efficiently obtaining the permit approvals. Frequent communication with stakeholders throughout the planning and remediation process also proved to be a key factor in timely completion of the project. The remediation of the stream involved the use of temporary bladder berms to divert surface water flow, water diversion piping, a sediment vacuum removal system, excavation of sediments using small front-end loaders, sediment dewatering, and waste packaging, transportation and disposal. Many safeguards were employed to protect several species of concern in the work area, water management during project activities, challenges encountered during the project, methods of Final Status Survey, and stream restoration. The planning and permitting effort for the Site Brook remediation began in May 2009 and permits were approved and in place by February 2011. The remediation and restoration of the Site Brook began in April 2011 and was completed in November 2011. The remediation of the Site Brook involved the use of temporary bladder berms to divert surface water flow, water diversion piping, a sediment vacuum removal system, excavation of sediments using small front-end loaders, sediment dewatering, and waste packaging, transportation, disposal, FSS, and restoration. Early and frequent communications with stakeholders proved to be a key factor in timely completion of the project. Challenges encountered during the remediation effort were overcome by proper planning and having preparedness procedures in place prior to executing the work. With the remediation and restoration successfully completed, the only remaining task is to monitor/maintain the restoration for 10 years. (authors)
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Managing an Aging Pump-and-Treat Groundwater Remediation System at the Fernald Preserve - 19557
The Fernald Preserve, Ohio, Site underwent restoration and remediation under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). With the exception of the Great Miami Aquifer, the CERCLA remediation was declared physically complete on October 29, 2006, and the site was turned over to the US Department of Energy Office of Legacy Management for long-term care and maintenance. The Record of Decision under CERCLA specifies a concentration-based cleanup that requires the extraction and treatment of Great Miami Aquifer groundwater above Final Remediation Levels (FRLs) until the full, beneficial use potential of the aquifer is achieved, including use as a drinking water source. The area of the aquifer targeted for remediation is 126.5 hectares (312.70 acres). The groundwater pumping remediation was designed by modeling cleanup with the Variable Saturated Analysis Model in 3 Dimensions (VAM-3D) modeling code, developed by Hydrogeologic Inc. The original design called for 23 extraction wells operating at 379 liters per minute (lpm) (100 gallons per minute [gpm]) to 1135 lpm (300 gpm) each for a system total of 18,073 lpm (4775 gpm). In 2014, the system was optimized down to 20 extraction wells operating at 379 to 1893 lpm each for a system total of 19,180 lpm (5075 gpm). To date, pumping has been an effective remediation technology for the aquifer. At the end of 2017, the area of the aquifer remaining above FRLs was down to 38.2 hectares (94.4 acres). From August 1993 through December 2017 (24 years), 6235 kilograms (kg) (13,733 pounds) of uranium were removed from the aquifer by the pumping of 1.74 x 10{sup 11} liters (46.2 billion gallons) of water. Since 2010, treatment of groundwater to achieve regulatory discharge limits at the Great Miami River has not been needed on a routine basis. The ongoing remediation is now essentially a pumping operation, and this water does not require treatment. Metrics reported in the annual Site Environmental Report for the groundwater remediation indicate that, based on the model-predicted estimate of the mass of uranium that needs to be removed from the aquifer to achieve a concentration-based cleanup, the cleanup is approximately 86% - 87% complete. Current model predictions indicate that pumping will need to continue an additional 16 years (until 2035) in some of the wells. During the additional 16 years, it is estimated that approximately 1012 kg (2231 pounds) of uranium will be removed from the aquifer. System pumping rates are designed to decrease over the course of the remaining 16 years, dropping down to a system total of 11,638 lpm (3075 gpm) in 2022 and a system total of 4163 lpm (1100 gpm) in 2033. Even with the designed decreases in pumping rates, it is estimated that approximately 1 x 10{sup 11} liters (26.6 billion gallons) of water will be pumped from the aquifer to remove 1012 kg (2231 pounds) of uranium. This indicates that the remaining 16 years of operation will be much less efficient than the first 24 years. Decreasing efficiency is common for pumping operations. The worst-case scenario is that decreasing concentration trends stabilize above the cleanup FRLs and remediation goals are never achieved. Performance assessments of the pumping remedy will need to be routinely conducted to determine if pumping should be discontinued, if it should be continued but optimized, or if the pumping technology can be supplemented with a different technology that will improve the outcome of the remediation and make the operation more efficient and successful. (authors)
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Estimating the Effects of Soil Remediation on Children’s Blood Lead near a Former Lead Smelter in Omaha, Nebraska, USA
Lead exposures from legacy sources threaten children’s health. Soil in Omaha, Nebraska, was contaminated by emissions from a lead smelter and refinery. The U.S. Environmental Protection Agency excavated and replaced contaminated soil at the Omaha Lead Superfund Site between 1999 and 2016. The goal of this study was to assess the association of soil lead level (SLL) and soil remediation status with blood lead levels (BLLs) in children living near or on the site. We linked information on SLL at residential properties with children’s BLLs and assigned remediation status to children’s BLL measurements based on whether their measurements occurred during residence at remediated or unremediated properties. We examined the association of SLL and remediation status with elevated BLL (EBLL). We distinguished the roles of temporal trend and the intervention with time-by-intervention-status interaction contrasts. All analyses estimated odds ratios (ORs) with a generalized estimating equations approach to ensure robustness under the complex correlations among BLL measurements. All analyses controlled for relevant covariates including children’s characteristics. EBLL (> 5 μg/dL ) was associated with both residential SLL [e.g., OR=2.00; 95% confidence interval (CI): 1.83, 2.19; > 400–800 vs. ≤ 200 ppm] and neighborhood SLL [e.g., OR=1.85 (95% CI: 1.62, 2.11; > 400–800 vs. ≤ 200 ppm)] before remediation but only with neighborhood SLL after remediation. The odds of EBLL were higher before remediation [OR 1.52 (95% CI: 1.34, 1.72)]. Similarly, EBLL was positively associated with preremediation status in our interaction analysis [interaction OR=1.18 (95%CI: 1.02, 1.37)]. Residential and neighborhood SLLs were important predictors of EBLLs in children residing near or on this Superfund site. Neighborhood SLL remained a strong predictor following remediation. Our data analyses showed the benefit of soil remediation. Results from the interaction analyses should be interpreted cautiously due to imperfect correspondence of remediation times between remediation and comparison groups. https://doi.org/10.1289/EHP8657
54 ENVIRONMENTAL SCIENCES↗
An approach to evaluating and monitoring ecological resources for sustainability on DOE remediation sites: Hanford as a case study - 15524
Protecting ecological and environmental resources is a worthy aspect of the Department of Energy's site missions, for each of its sites, during and after remediation. Ecological resources are important to a range of stakeholders, including regulatory agencies, resource agencies, natural resource trustees, Tribal governments, and the public, and may be an essential component of Native American cultural resources. Because the nature and value of ecological resources can change over time as a result of remediation, succession, and global climate change, it is imperative for DOE to have instituted an acceptable method of evaluating resources before initiation of active remediation, over the ensuing century when institutional and engineering controls are considered to be in effect. Having such a methodology in place also would be key to resource sustainability. Department of Energy sites generally have environmental programs, so instituting specific unified practices for evaluating resources should not be difficult to implement. Instituting these practices would assure the public that ecological resources, as well as human and cultural resources, are being protected now, and can be protected into the future. Key ecological species and/or unique habitats have been preserved at Department of Energy sites since the mid-20. century because of federal government stewardship. Such preservation is particularly true for the sites with larger land areas, including the Hanford Reservation, the Idaho National Laboratory and the Savannah River Site. Individual sites typically have extensive studies of site biodiversity, but site resources are not routinely examined within a regional or national context (Eco-region). The evaluation of the on-site resources with those resources in the appropriate Eco-region provides a context for 'valuing' on- site resources. On-site resources should also be evaluated in terms of federal and state legislation where species may have legal protection and require legal consideration during remediation if present or adjacent to the remediation site. A method is needed in this study for evaluating ecological resources prior to remediation and during remediation, and a paradigm is proposed that will ensure sustainability. Finally, in a period of climate change and instability, developing methods of evaluating ecological resources is essential to successful protection, enhancement, and sustainability. The ecological methodology is part of a Hanford site-wide Risk Review Project, conducted by the Consortium for Risk Evaluation with Stakeholder Participation (CRESP). Our method adapts an existing methodology that includes using established levels for evaluating ecological resources by expanding the existing methodology to include field work for validating previous resource level designations, to assess the occurrence of invasive/exotic species, and to identify landscape scale features (patch size, connectivity). Evaluations should be conducted in the remediation unit itself, and in a buffer zone surrounding the remediation site. The methodology described has been applied to several remediation areas at Hanford, and issues that emerged during its application are discussed. The methodology can be applied at the major sites. Application of the Eco-region analysis will provide regulators and the public with an understanding of the value of the ecological resources in relation to the region, as well as an appreciation for the stewardship role the Department of Energy has played in protecting these resources since the beginning of the Cold War Era and can continue to do so sustainably. (authors)
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