Conceptual Site Model

This report was prepared under contract to the Department of Defense Environmental Security Technology Certification Program (ESTCP). The publication of this report does not indicate endorsement by the Department of Defense, nor should the contents be construed as reflecting the official policy or position of the Department of Defense. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Department of Defense.

Various techniques can be considered for the remediation of contaminated sediments. The options can include capping, dredging, or physical, biological, and/or chemical treatments and natural recovery. Natural recovery could be beneficial over dredging due to a reduction in costs and lack of solid disposal requirements. Source control, however, is a major issue for sustainable remediation. In a case study, surface and core sediment samples were collected from a harbor on the north bank of the St. Lawrence River in the province of Quebec to assess heavy metal pollution and determine if natural recovery was occurring. Comparing the results of all analysis done for sediment for three different years (2015, 2017 and 2019) in the sampling area, it can be seen that some metals increased, some decreased and some of them showed nearly the same level of contamination. The results also indicated that during the sampling periods, copper, zinc and chromium were the main elements that exceeded the occasional effect level based on the Environment Canada sediment quality guidelines. Therefore, metal pollution has become a noticeable problem in this area and natural recovery was not achieved for several metals due to ongoing contamination and thus source control is critical.

Fig. 1. Plan view map of the oil and groundwater U-238 contamination at Savannah River Site (SRS F-area, upper aquifer zone) in (a) 1994, (b) 2001 and (c) 2008, displayed in a web browser as a Google Maps bitmap overlay created in VisIt [1].

At the request of the U.S. Department of Energy (DOE), Pacific Northwest National Laboratory (PNNL) embarked on a new initiative to strengthen the technical defensibility of the Hanford site-wide groundwater model (SGM) used to make groundwater flow and transport predictions at the U.S. Department of Energy's Hanford Site in southeastern Washington State (Figure 1.1). The initial focus of the initiative is the characterization of major uncertainties in the current conceptual model that would affect model predictions. The long-term goals of the initiative are the development and implementation of a stochastic uncertainty estimation methodology in future assessments and analyses using the site-wide groundwater model. This report focuses on the development and implementation of the uncertainty analysis framework. The overall technical approach for this framework will closely follow the recommendations of the SGM external peer review panel made in 1999 (Gorelick et al. 1999). As suggested by the panel, the framework being developed acknowledges the inherent uncertainty in conceptual model representations and associated model inputs and thus in any predictions. This new framework acknowledges that prescribed processes, physical features, initial and boundary conditions, system stresses, field data, and model parameter values are not known and cannot be known with certainty and, as a result, predictions of heads and concentrations in three dimensions over time will be uncertain as well. The approach will specifically address those areas of special interest that were identified by the expert panel. These include uncertainty related to

Communication with stakeholders, regulatory agencies, and the public is an essential part of implementing different remediation and monitoring activities, and developing site closure strategies at contaminated sites. Modeling of contaminant plume evolution plays a critical role in estimating the benefit, cost, and risk of particular options. At the same time, effective visualization of monitoring data and modeling results are particularly important for conveying the significance of the results and observations. In this paper, we present the results of the Advanced Simulation Capability for Environmental Management (ASCEM) project, including the discussion of the capabilities of newly developed ASCEM software package, along the its application to the F-Area Seepage Basins located in the U.S. Department of Energy Savannah River Site (SRS). ASCEM software includes state-of-the-art numerical methods for simulating complex flow and reactive transport, as well as various toolsets such as a graphical user interface (GUI), visualization, data management, uncertainty quantification, and parameter estimation. Using this software, we have developed an advanced visualization of tritium plume migration coupled with a data management system, and simulated a three-dimensional model of flow and plume evolution on a high-performance computing platform. We evaluated the effect of engineered flow barriers on a nonreactive tritium plume, through advanced plume visualization and modeling of tritium plume migration. In addition, we developed a geochemical reaction network to describe complex geochemical processes at the site, and evaluated the impact of coupled hydrological and geochemical heterogeneity. These results are expected to support SRS's monitoring activities and operational decisions.

I would like to acknowledge the funding for this project generously provided by The Dow Chemical Company (Dow), The University Consortium for Field-Focused Groundwater Contamination Research directed by Dr. Cherry, The Natural Sciences and Engineering Research Council of Canada (NSERC) Industrial Research Chair held by Dr. Parker and Landesanstalt fur Altlastenfreistellung des Landes Sachsen-Anhalt (LAF). In addition, in-kind support was provided by FLUTe™, Solinst Canada Ltd. and Golder Associates Ltd.

Background and aim: Chemical accidents cause significant danger for residents living close to chemical facilities. For this reason, this study assessed the impacts of a simulated chemical accident on surrounding residents in the city of Ray, Iran. Methods: In this scenario-based case study in 2015, the Areal Location of Hazardous Atmospheres (ALOHA) model was applied to simulate a toxic chemical release from a chlorine warehouse in Shourabad, Ray, Iran. The population of the area was calculated based on the latest census in Iran, 2011. The atmospheric variables included were wind speed, air temperature, and relative humidity. We also included data on pollution source such as diameter, length and volume, and condition of chemicals. The simulation was repeated for each seasonal period. The simulated threat zones were mapped using Geographical Information System. The percentage of residents sustaining injuries and death was calculated using probit. Results: The maximum and minimum simulated threat zones by chlorine release are during summer and winter at 8.8 and 6.4 kilometers respectively. The total affected population was estimated at approximately 30,000 people. The greater percent of injuries and death was estimated to occur in the winter and autumn, compared to summer and spring, because of greater climatic instability. The number of individuals affected by chlorine release in the spring, summer, autumn and winter at 8.3, 8.8, 7.6 and 6.4 kilometers, are estimated at 22,500, 25,000, 28,100 and 27,500, respectively. Populations located in hot and warm zones of toxic chemical releases should have access to medical resources. Conclusions: The results showed that relevant factors impact human vulnerability, and these should be examined to mitigate the harmful consequences of chemical accidents. Establishing a multi-level Emergency Response Program is also recommended in the area under study.

This is the fi rst of a two-part review article on the assessment and management of contaminated sediments. Part II, "Evaluating Risk and Monitoring Sediment Remedy Effectiveness," is available in the online edition of IEAM Volume (1), Number (1).

This is the fi rst of a two-part review article on the assessment and management of contaminated sediments. Part II, "Evaluating Risk and Monitoring Sediment Remedy Effectiveness," is available in the online edition of IEAM Volume (1), Number (1).

ABSTRACTA wide range of anthropogenic activities have caused various problems to the aquatic environment, leading to economic, social, and environmental losses. The use of materials for the recovery of water quality is very important due to the water scarcity scenario present in different parts of the world. The use of sawdust as an organic adsorbent for P removal in eutrophic environments attempts to address both water quality preservation and possible application of the organic adsorbent as fertilizer for agricultural practices. This use will result in important contributions to the water and food security. In this work, we performed laboratory experiments to study P adsorption and to evaluate possible adsorption of metals and emerging contaminants by sawdust. The experiments were carried out in 36 microcosms (glass jars), using 50% of the flasks as treatments (containing bags with sawdust) and the rest of the flasks as control (water and sediment without sawdust). For future appl...

a study on warning systems, some of which was translated into the standards included here as Appendix F. Lee L. Williams of the University of Tennessee was heavily involved in the preparation of Appendices B, G, and K. Finally, the U.S. Army Nuclear and Chemical Agency provided much of the text regarding training and exercises included in sections 8.19 and 8.20. We also wish to express appreciation to the people and agencies who have provided insightful comments on this report during its long period of evolution. The U.S. Army, Office of the Assistant Secretary for Installations, Logistics, and Environment, and the Federal Emergency Management Agency (FEMA), Office of Technological Hazards, have provided extensive review and guidance of this effort. In addition, the report has been shaped by comments received from the affected FEMA Regional offices, the state and county governments involved in the Chemical Stockpile Emergency Preparedness Program, and the Centers for Disease Control and Prevention of the U.S. Department of Health and Human Services. Finally, we gratefully acknowledge the notable contributions made by Cynthia J. Coomer, Lori A Warnecke, and Beverly J. Norton in organizing and producing the document. TABLE OF CONTENTS LIST OF FIGURES vi LIST OF TABLES vi ACRONYMS vii 1.

The U.S. Department of Energy (DOE) recently invested in developing a numerical modeling toolset called ASCEM (Advanced Simulation Capability for Environmental Management) to support modeling analyses at legacy waste sites. This investment includes the development of an open-source user environment called Akuna that manages subsurface simulation workflows. Core toolsets accessible through the Akuna user interface include model setup, grid generation, sensitivity analysis, model calibration, and uncertainty quantification. Additional toolsets are used to manage simulation data and visualize results. This new workflow technology is demonstrated by streamlining model setup, calibration, and uncertainty analysis using high performance computation for the BC Cribs Site, a legacy waste area at the Hanford Site in Washington State. For technetium-99 transport, the uncertainty assessment for potential remedial actions (e.g., surface infiltration covers) demonstrates that using multiple realizations of the geologic conceptual model results in greater variation in concentration predictions than when a single model is used.

Ongoing developments in geological and hydrogeological investigation techniques, especially direct-push methods, have led to an increase in the quality, density and spatial resolution of data available from such investigations. This has created new challenges in the development of numerical models in terms of accurately and efficiently translating detailed and complex conceptual models into effective numerical models. Suitable geometrical and numerical modelling tools are essential in order to meet these challenges. This paper describes the development of a three-dimensional hydrogeological flow model for a contaminated site near Berlin, Germany, based on high-resolution geological data obtained principally using direct-push methods. The available data were first interpreted to construct a detailed GIS-based geological model, which formed the basis of the conceptual site model. The conceptual model was then translated into a geometrical model, which was used to create a finite element numerical model. An innovative geometry object-based approach enabled the complex structural details of the conceptual model to be accurately reproduced in the numerical model domain. The resulting three-dimensional steady-state unconfined flow model was successfully calibrated using external automated calibration software, whereby parameter values for groundwater recharge and hydraulic conductivity were determined.

This is the second of a two-part review article on the assessment and management of contaminated sediments. Part I, "Developing an Effective Investigation and Risk Evaluation Strategy," appears in both the print and online editions of IEAM Volume (1), Number (1).

Ongoing developments in geological and hydrogeological investigation techniques, especially direct-push methods, have led to an increase in the quality, density and spatial resolution of data available from such investigations. This has created new challenges in the development of numerical models in terms of accurately and efficiently translating detailed and complex conceptual models into effective numerical models. Suitable geometrical and numerical modelling tools are essential in order to meet these challenges. This paper describes the development of a three-dimensional hydrogeological flow model for a contaminated site near Berlin, Germany, based on high-resolution geological data obtained principally using direct-push methods. The available data were first interpreted to construct a detailed GIS-based geological model, which formed the basis of the conceptual site model. The conceptual model was then translated into a geometrical model, which was used to create a finite element numerical model. An innovative geometry object-based approach enabled the complex structural details of the conceptual model to be accurately reproduced in the numerical model domain. The resulting three-dimensional steady-state unconfined flow model was successfully calibrated using external automated calibration software, whereby parameter values for groundwater recharge and hydraulic conductivity were determined.

report is based on risk estimates prepared by the University of California, Davis (UC Davis) at the Laboratory for Energy-Related Health Research (LEHR or the Site). ” As discussed in DSCSOC comments, some of the UCD risk estimates are based on technically invalid approaches such as the use of cooccurrence-based sediment quality guidelines. This issue is discussed further below. Further, the risk estimates are based on a limited set of constituents of concern compared to the vast number of potentially hazardous chemicals at the LEHR Superfund site. These issues have been discussed in detail in comments of provided to the RPMs, and UCD and DOE as responsible parties. The comments are on the DSCSOC website,

Years of production of radioactive materials at the Hanford Site in southeastern Washington State has resulted in contamination of surface, subsurface, and surface water environments. Cleanup of the site has been aided by various tools, including computer software used to predict contaminant migration in the future and estimate subsequent impacts. The System Assessment Capability (SAC) is a total systems tool designed to simulate the movement of contaminants from all waste sites at Hanford through the vadose zone, the unconfined aquifer, and the Columbia River. Except for iodine-129, most of the contaminants modeled by SAC have acceptably matched field measurements. The two most likely reasons for the inconsistency between the measured field data and SAC modeled predictions are an underestimated inventory and an overestimated sorption value (Kd). Field data tend to be point measurements taken from near the surface of the unconfined aquifer. Thus, the depth of the iodine-129 contamin...

Ongoing developments in geological and hydrogeological investigation techniques, especially direct-push methods, have led to an increase in the quality, density and spatial resolution of data available from such investigations. This has created new challenges in the development of numerical models in terms of accurately and efficiently translating detailed and complex conceptual models into effective numerical models. Suitable geometrical and numerical modelling tools are essential in order to meet these challenges. This paper describes the development of a three-dimensional hydrogeological flow model for a contaminated site near Berlin, Germany, based on high-resolution geological data obtained principally using direct-push methods. The available data were first interpreted to construct a detailed GIS-based geological model, which formed the basis of the conceptual site model. The conceptual model was then translated into a geometrical model, which was used to create a finite element numerical model. An innovative geometry object-based approach enabled the complex structural details of the conceptual model to be accurately reproduced in the numerical model domain. The resulting three-dimensional steady-state unconfined flow model was successfully calibrated using external automated calibration software, whereby parameter values for groundwater recharge and hydraulic conductivity were determined.

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. MNA can also be used after active remediation has been completed (e.g., pump-and-treat) as a polishing step to reach ultimate remedial action objectives. However, MNA and existing monitoring guidance primarily target situations where the remedial action objectives are met within a few decades. When timescales for passive remediation extend to many decades, 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 receptors will not be impacted within the remediation timeframe.

ABSTRACT In the early days of North America settlement industry was encouraged by government to utilize natural resources and bring development and wealth to communities. As populations grew and other demands developed, regulations were created to protect natural resources for multiple uses. Industry then argued that environmental regulations increased costs and reduced their ability to compete nationally and internationally. It is only over the last 50 years that environmental regulations and legal precedents have placed substantial responsibility for the protection of natural resources on industry. In recent decades, product advertising and marketing has engaged the consumer as another stakeholder in shaping industry's attitude regarding environmental management and protection. The financial model for business has expanded with a growing economy and an increase in stakeholders. Fuller cost accounting incorporating the expense and benefit of environmental protection and remediation has changed the equation of profitability. Convergence of the corporate need to make a profit for investors together with meeting consumer environmental needs will continue toward the common goal of economic sustainability.

The use of chemical warfare agents intentionally has become a great concern in the arena of the cold war. On the other hand, there has always been a threat on civilian population due to their mass destruction effects, including psychological damage and a great deal of discussion how to respond to it in terms of medical management. It is very important to provide the best lifesaving medical care and triage in a chemical-contaminated area. Mass casualties exposed to chemical agents require immediate medical intervention to save their lives and should be classified in accordance to medical care priorities and available medical sources, including antidotes and sophisticated health facilities. Establishing the decontamination area for chemical casualties where it is located at the suitable place with respect to the wind direction is necessary. To overcome the mass destruction effects of chemical warfare agents following the terrorist attack, we must have the emergency medical response plan involving experienced triage officers and medical care providers to be able to perform medical management in the chemical-contaminated area and health facilities.

in Washington State is currently developing the means to assess the cumulative impact to human and ecological health and the regional economy and cultures from radioactive and chemical waste that will remain at the Hanford Site after the site closes. This integrated system is known as the System Assessment Capability (SAC). The SAC Risk/Impact Module discussed in the article uses media-and timespecific concentrations of contaminants estimated by the transport models of the integrated system to project potential impacts on the ecology of the Columbia River corridor, the health of persons who might live in or use the corridor or the upland Hanford environment, the local economy, and cultural resources. Preliminary Monte Carlo realizations from the SAC modeling system demonstrate the feasibility of large-scale uncertainty analysis of the complex relationships in the environmental transport of contaminants on the one hand and ecological, human, cultural, and economic risk on the other. Initial impact results show very small long-term risks for the 10 radionuclides and chemicals evaluated. The analysis also helps determine science priorities to reduce uncertainty and suggests what actions matter to reduce risks. The Groundwater Protection Project is a major US Department of Energy (DOE) project at the Hanford Site in Washington State. Among other activities, the project is currently developing the tools and supporting data to assess the cumulative impact to human and ecological health and to the regionÕs economy and cultures from radioactive and chemical waste that will remain at the Hanford Site after the site closes. Figure 1 shows the Hanford Site, the nearby Tri-Cities (Richland-Pasco-Kennewick) area, and the principal sources of contamination. The 100 Areas are the sites of nine former individual plutonium production reactors and associated facilities, designated by letters (e.g., the 100-D Area). These sites contain irradiated spent fuel, miscellaneous underground storage tanks, liquid discharge sites, and solid waste burial grounds. The Central Plateau 200 Areas (chemical separations plants, waste storage, and associated facilities) contain spent nuclear fuel, liquid discharge sites, high-level radioactive and chemical waste in underground storage tanks, and low-level solid waste burial grounds. The 300 Area (nuclear fuel fabrication and research) contains some spent fuel and nuclear material, surplus contaminated facilities, liquid discharge sites, and solid waste burial grounds. The integrated system of new and legacy (preexisting) models and data used to analyze the path of contaminants from these sites through the environment, and the associated risks, is known as the System Assessment Capability (SAC). The SAC Risk/Impact Module is a component of SAC designed to assess the impacts to the environment and humans of radionuclides and chemicals in the Columbia River, near-shore environment, and nearby communities from Hanford Site operations for up to 10,000 years and meet a variety of federal orders and

In recent months remediation activities at Hanford 100 Area sites–located along the shores of the Columbia River near Richland, Washington–have accelerated in order to protect aquatic species from discharges of hexavalent chromium (CrVI). These activities ...

Dear Mr. Lux: Enclosed is a summary of the subject meeting and the U.S. Nuclear Regulatory Commission staff’s recommendations for a path forward for each of the groups of deficiencies that were discussed at the meeting. If you have any questions regarding this letter, please contact me at (301) 415-6664 or by e-mail at klk@nrc.gov. Sincerely, /RA/

(PNNL) have embarked upon a new initiative designed to strengthen the technical defensibility of the groundwater flow and transport model at the Hanford Site in Southeast Washington State and to develop a more robust capability to incorporate uncertainty into the model. One aspect of the initiative is developing and using a three-dimensional transient inverse modeling approach to estimate the hydraulic conductivities, specific yields, and other site-wide scale parameters that incorporates data on the transient behavior of the unconfined aquifer system resulting from Hanford Site waste management since 1943. Over the historical period of Hanford operations, the large volumes of wastewater discharged to a variety of waste facilities resulted in large water table changes over most of the Hanford Site and created significant groundwater mounds (in excess of 20 m) under waste management facilities in the central part of the site. Since 1988, the mission of the Hanford Site has changed from producing weapons to restoring the environment. Thus wastewater discharges have declined significantly, which has caused significant water table declines. The three-dimensional transient inverse calibration, which an external peer review panel recommended to DOE, is being performed using UCODE, a universal inverse modeling code developed jointly by the U.S. Geological Survey and the International Groundwater Modeling Center of the Colorado School of Mines. The work uses the existing consolidated site-wide groundwater model (SGM) implemented with the Coupled Fluid Energy and Solute Transport (CFEST) code, which is the forward model whose parameters are estimated by UCODE. The transient inverse calibration uses approximately 70,000 water level measurements made at the Hanford Site since the mid-1940s. Compared with the prior model, the initial baseline transient inverse calibration effort (Cole et al. 2001a) significantly improved the ability of the baseline model to simulate historical trends in water table changes over the entire site for the 1943-1996 period of calibration. Most notably improved were the historical trends of water table changes and mound building observed near major discharge facilities in the 200 West Area. The focus of the inverse modeling initiative in the following year (Vermeul et al. 2001) was to use the developed inverse calibration methodology to test an alternative conceptual model (ACM-1) that no longer considered the underlying basalt bedrock system the no-flow base of the unconfined aquifer system as it had in the past. This alternative SGM model was used to examine and evaluate a variety of mechanisms that affect intercommunication between the Hanford Site unconfined aquifer system and the underlying upper basalt-confined aquifer system. The focus of the ACM-2 inverse modeling initiative, as documented in this report, has been to 1) address data and model implementation limitations identified in the ACM-1 model, 2) complete the implementation and evaluation of the facies-based approach for representing the hydraulic conductivity distribution in both the Hanford and middle Ringold Formations, 3) develop the approach and implementation methodology for generating multiple ACMs of Unit 1 zonation and Ringold mud unit distribution based on geostatistical data analysis, and 4) develop an approach for inverse modeling of these stochastic ACMs. The ACM-2 transient inverse model was developed to test the SGM that incorporates conceptual model modifications that were identified for investigation based on knowledge gained during previous inverse calibration efforts. The primary modifications incorporated into ACM-2 that were not in Hydraulic conductivity of conductive units: In general, the solution was sensitive to the hydraulic conductivity of the more conductive units. The only permeable units not determinable by the inverse were Ringold Units 7 and 9, which are moderately permeable and situated deeper in the profile, where fewer observational data are available. Hydraulic conductivity of the Ringold mud units: The solution was sensitive to the hydraulic conductivity of the lower-conductivity, slightly more extensive mud unit (Unit 8) and insensitive to Unit 6. Because of the limited saturated extent of the upper Ringold mud (Unit 4), this parameter was not included in the inverse. Vertical hydraulic conductivity of underlying basalt layer: The solution was sensitive to this parameter, which affects basalt leakage. Features associated with increased basalt leakage: In general, hydraulic conductivity associated with head-dependent flux boundaries at the erosional window and thrust fault was insensitive. One exception was a section of fault in Cold Creek Valley upgradient of the Cold Creek flow impediment. High basalt heads upgradient of this feature are the primary reason for the solution's increased sensitivity to hydraulic conductivity, controlling leakage over this section of the thrust fault. Specific yield of the conductive units containing the water table: The solution was generally insensitive to all tested specific-yield parameter values. The specific yield of several facies of the Hanford and Ringold formations across the 200 Area plateau, where the largest amount of groundwater mound buildup occurs, however, were marginally sensitive for a limited time during the inverse process but became insensitive as the inverse progressed. Anisotropy ratio of all conductive hydrogeologic units: The solution was insensitive to all anisotropy parameters. Components of surface recharge: The solution was insensitive to areally distributed surface recharge but sensitive to run-on recharge from Cold Creek, Dry Creek, and Rattlesnake Hills.

for their good editing work. Thanks also to Grace Mojtabai for inspiration; the phrase "host and hostage" is hers. Many individuals assisted me in my research, including Pam Allison and Jerry Stein, who read drafts of the manuscript, and archivists, including Sidnye Johnson and Andy Wilkinson. Numerous others-boosters, bashers, and just plain citizen neighbors-gave generously of their time, memories, and knowledge about Pantex. Many are named in the essay, many more are behind the scenes-all shaped my understanding of the history of Pantex Plant. Any errors are my own.

Site investigations of contaminated land are associated with high costs. From a societal perspective, just enough economic resources should be spent on investigations so that society's limited resources can be allocated to sustainable development in the best way. The solution is to design investigation programs that are cost-effective, which can be performed using Value of Information Analysis (VOIA). The principle is to compare the benefit at the present state of knowledge with the benefit that is expected after an investigation has been performed. Bayesian methods are used to calculate the expected change, i.e. the value of the investigation. A general framework for VOIA of site investigations is presented. The framework consists of seven modules: (i) the landuse scenario, (ii) the objective of investigation, (iii) a conceptual site model, (iv) a data collection module, (v) a prior information module, (vi) an uncertainty reduction module, and (vii) a decision model. The decision model is based on Bayesian risk-cost-benefit decision analysis. The result is an estimate of the value of an investigation program, and for specific problems, the optimal number of samples. Applications of the method illustrate that the objective of the investigation, the landuse, and the benefit of remediation have major impacts on the results. The main contributions of this work are: (1) a general framework for VOIA of siteinvestigations in remediation projects, (2) a tool-kit of VOIA models for practical application, and (3) a knowledge base of strengths and weaknesses of the methodology, including recommendations.

A number of waste trenches at cribs at Hanford's BC Cribs and Trenches site, which received about 10 Mgal of scavenged tank waste with elevated concentrations of technetium-99 and nitrate, are currently being evaluated for remediation. The objective of this study was to investigate the influence of fine-scale heterogeneity (i.e. horizontal laminations, cross-bedding) on the large-scale transport behavior of mobile contaminants through the vadose zone with the purpose of developing a remedial strategy. The vertical heterogeneity structure, conditioned on grain size distributions and geophysical logs (water content and natural isotopes), was developed from a single borehole at the site. Geostatistical methods were used to impose the 3-D spatial correlation structure from the nearby well-characterized experimental site to merge the heterogeneities at various scales. Flow and transport properties were derived using physically-based property transfer models. The STOMP simulator was t...

In this paper, we address the issue of evaluating the seismic site response for sites located on large alluvial plains, for which no reference sites can be identified, but some earthquakes can be simultaneously recorded at both surface and depth. In the proposed method, surface and borehole records are firstly used to assess the local 1D velocity model, then a model representing a virtual reference rock site is defined, and finally the site spectral amplification is calculated through numerical modeling. The effectiveness of the method is demonstrated at the site of Mirandola (Italy). This site is located in an area which suffered heavy damage during the seismic sequence that started in Northern Italy with the Mw = 5.8 event on May 20th, 2012. That time, the site hosted an accelerometer of the National Accelerometric Network, which recorded the whole sequence. A new station, named MIRB (MIRandola Borehole), was installed during 2014; it is equipped with three accelerometric sensors deployed at surface, 31 and 126 m depth, respectively. The results of this study evidence that Mirandola is characterized by an amplification level consistent with that of a class-C soil for up to a period of about 0.45 s, while for higher periods, the amplification lays between class-B and C soils.

• We are committed to act as stewards of our environment to achieve our mission in accordance with all applicable environmental requirements. •We set continual improvement objectives and targets, measure and document our progress, and share our results with our workforce, sponsors, and public. •We reduce our environmental risk through legacy cleanup, pollution prevention, and long-term sustainability programs.

It will be necessary to install new monitoring wells and accumulate background data on the groundwater from those wells before statistical comparisons can be made. Until then, the constituents listed above will be evaluated by tracking and trending concentrations in all wells and comparing these results with the corresponding drinking water standard (DWS) or Hanford Site background concentration for each constituent. If a comparison value (background or DWS) for a constituent is exceeded, the U.S. Department of Energy (DOE) will notify Washington State Department of Ecology (Ecology) per WAC 173-303-645(9)(g) requirements (within 7 days or a time agreed to between DOE and Ecology).

The possible threat posed by terrorists using chemical warfare agents (CWAs) against civilian targets is a major concern, reflecting the fact that CWAs are highly toxic to unprotected populations, with releases as vapors or aerosols likely to produce mass casualties on a highly localized basis within minutes or hours after an incident. A conceptual site model is developed and mixed model regression is used to estimate concentration values for the vesicant sulfur mustard (HD) based on the output from computational fluid dynamics (CFD) simulation following wind tunnel experimentation. The analysis provides a first-approximation of the spatial and temporal distribution of potential exposures within a set of 50 m × 50 m × 2 m grids across a 1000 m width by 300 m height by 2250 m length domain in a geographic information system (GIS) environment. The HD concentration values are calculated as log-averaged mean and the 95% confidence intervals for each grid at 1.9 d and 6.0 d after initial release. The technique offers a statistically valid means for rapidly generating unbiased first-approximations of concentration values subsequent to an initial release as an alternative to extensive monitoring or multiple runs of CFD models to parameterize potential exposure to HD spatially and temporally.

An econometric model has been developed that represents the cost structure of water supply and waste water treatment in an urban area. This paper proposes a method to capture the fi nancial characteristics of the underlying organisation and addresses the steps and the conceptualisation in order to create a cost structure for municipal water utilities. The estimation procedure is based on a multivariate regression approach and the cost structure is represented by a parametrical expression (cost function). This function has been used for the purpose of analysing the observed system in terms of effi ciency, technology, capacity, fi nancial state etc. In the mathematical formula the estimated parameters relate certain system input components to costs, which are important in order to understand the key drivers. An empirical analysis is undertaken for a number of utilities in Sweden.

In recent months remediation activities at Hanford 100 Area sites – located along the shores of the Columbia River near Richland, Washington – have accelerated in order to protect aquatic species from discharges of hexavalent chromium (CrVI). These activities have focused on expanding existing groundwater pump-and-treat remedies, together with pilot-testing complementary in situ technologies. Comparative analyses of remedial alternatives within the context of remedial process optimization led by CH2M HILL Plateau Remediation Company (CHPRC) employed groundwater flow, particle tracking, and transport modeling using MODFLOW, MODPATH, and MT3DMS, respectively. As the conceptual site models for each of the groundwater operable units have developed, so too has the representation of the key features and processes within the numerical model. Herein the initial model construction and calibration are described and then the stepwise integration of several features and processes are presented,...

The "sediment quality triad" approach was used to assess the effects of dredging on the sediment quality of a new marina in the Trenton Channel of the Detroit River, and to evaluate spatial and temporal variation in sediment quality in the Trenton Channel. Samples were collected in November of 1993 (10 months after dredging) and characterized by chemical analysis. sediment bioassays. and assessment of benthic invertebrate communities. The three study components indicated little difference in sediment quality at dredged sites in the marina relative to nearby areas in the Trenton Channel, and little change in sediment quality of Trenton Channel sites relative to conditions reported in the mid-1980s. These results suggest that improvement in sediment quality in the Trenton Channel, due to dredging or natural processes, will depend on elimination of sediment "hot spots" and other upstream contaminant sources. Concentrations of chemical contaminants, especially metals and polycyclic aromatic hydrocarbons, exceeded concentrations associated with effects on biota and were significantly correlated with results of sediment bioassays and characteristics of benthic communities. Laboratory sediment bioassays with Hyalella azteca and Chironomus tentans produced better discrimination among sites with differing degrees of contamination than did characterization of benthic communities, which were dominated by oligochaetes at all sites in the marina and the Trenton Channel.

Intrusive characterization was conducted to obtain data and information needed for planning remediation strategies for the Hanford Site’s 618-10 burial ground trenches, which contain very high dose rate and very highly alpha contaminated items. The term “intrusive” is used to distinguish these activities from previously conducted “non-intrusive” characterization, which was performed without exposing personnel or the environment to waste material. Planning for remediation requires better understanding of the type, quantity, and condition of the materials deposited into the trenches than has been obtained through record searches and previous nonintrusive characterization activities. Intrusive characterization is defined as characterization activities that will remove materials for sampling and analysis from within selected 618-10 Burial Ground trenches. Exploratory test pitting was performed with excavations up to 6 meters deep and approximately 2 meters wide (at the base) and cross c...

The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. The findings of this report are not to be construed as an official Department of the Army position, unless so desig-nated by other authorized documents. Dredging Operations and Environmental Research Program

: The high cost of chemical analyses and bioassays of dredged material makes it necessary for decision makers to limit testing to that which will sufficiently characterize the sediment to evaluate a selected disposal alternative. This report offers guidance for limiting the amount of testing necessary and considers other factors that could potentially reduce the cost of testing dredged material. The importance of an initial site evaluation to reduce the extent of dredged material testing is stressed. Unless a reason to believe that contamination exists can be established through examination of historical data and other site characteristics, no testing is warranted. The need for testing can sometimes be eliminated by examination of regulatory criteria for categorical exclusions, i.e., circumstances under which no testing is required. Additional cost savings can sometimes be generated during the scoping process by amelioration of the concerns of interested parties prior to preparation...