EPA Land and Waste Management Research
Methods, Models, Tools, and DatabasesModels
2DFATMIC simulates subsurface flow, transport, and fate of contaminants that are undergoing chemical or biological transformation. The model is applicable to transient conditions in both saturated and unsaturated zones. The flow module is a Galerkin finite element solution of Richard's equation. The transport module is a hybrid Lagrangian-Eulerian approach with an adapted zooming and peak capturing algorithm. This model can almost eliminate spurious oscillation, numerical dispersion, and peak clipping due to advective transport.
3DFATMIC simulates subsurface flow, transport, and fate of contaminants which are undergoing chemical and/or biological transformations. The model is applicable to transient conditions in both saturated and unsaturated zones. The flow module is a Galerkin finite element solution of Richard's equation. The transport module is a hybrid Lagrangian-Eulerian approach with an adapted zooming and peak capturing algorithm. This model can almost eliminate spurious oscillation, numerical dispersion, and peak clipping due to advective transport.
- Three-Dimensional Finite Element Model of Water Flow Through Saturated-Unsaturated Media (3DFEMWATER) and Three-Dimensional Lagrangian-Eulerian Finite Element Model of Waste Transport Through Saturated-Unsaturated Media (3DLEWASTE)
3DFEMWATER and 3DLEWASTE are related and can be used together to model flow and transport in three dimensional, variably-saturated porous media under transient conditions with multiple distributed and point sources/sinks. These models can be used to apply the assimilative capacity criterion to development of wellhead protection areas.
The complexity of 3DFEMWATER/3DLEWASTE numerical models requires that they be used by experienced numerical modelers with strong background in hydrogeology. 3DFEMWATER is designed to simulate the movement of moisture through variably saturated porous media. 3DLEWASTE is designed to simulate solute transport through variably saturated porous media.
BIOCHLOR is a screening model that simulates remediation by natural attenuation of dissolved solvents at chlorinated solvent release sites. BIOCHLOR includes three different model types:
- Solute transport without decay
- Solute transport with biotransformation modeled as a sequential first-order decay process
- Solute transport with biotransformation modeled as a sequential first-order decay process with two different reaction zones (i.e., each zone has a different set of rate coefficient values)
- Bioplume II
BIOPLUME II is a simulation that computes concentrations of dissolved hydrocarbon under the influence of oxygen-limited biodegradation in an aquifer. The model solves the solute transport equation for both hydrocarbon and oxygen, assumes an instantaneous reaction between oxygen and hydrocarbon, and combines the two plumes using the principle of superposition. Computations account for convection, dispersion, mixing, and biodegradation effects. Also, the program can simulate slow hydrocarbon plumes undergoing biodegradation and can simulate in situ biorestoration schemes such as the injection of oxygenated water. Moreover, the model can simulate re-aeration and anaerobic biodegradation as first-order decay in hydrocarbon concentrations.
- Bioplume III
BIOPLUME III is a two-dimensional finite difference model for simulating the natural attenuation of organic contaminants in groundwater due to the processes of advection, dispersion, sorption, and biodegradation. Biotransformation processes are potentially important in the restoration of aquifers contaminated with organic pollutants. As a result, these processes require evaluation in remedial action planning studies associated with hydrocarbon contaminants.
BIOSCREEN is a screening model that simulates remediation through natural attenuation of dissolved hydrocarbons at petroleum fuel release sites. The model is designed to simulate biodegradation by both aerobic and anaerobic reactions.
- Center for Subsurface Modeling Support (CSMoS)
The primary goals of CSMoS are to provide direct technical support in subsurface model applications, and to manage and support the groundwater models and databases resulting from the EPA research. The research includes the:
- Fate and transport of contaminants in the subsurface
- Development of methodologies for protection and restoration of groundwater quality
- Evaluation of subsurface remedial technologies
- Exposure Model for Soil-Organic Fate and Transport (EMSOFT)
EMSOFT is used
- To determine concentrations of contaminants remaining in the soil over a given time (when the initial soil concentration is known);
- To quantify the mass flux (rate of transfer) of contaminants into the atmosphere over time; and
- To subsequently calculate contaminant air concentrations by inputting mass flux values into atmospheric dispersion models.
FOOTPRINT is a screening model used to estimate the length and surface area of benzene, toluene, ethylbenzene, and xylene (BTEX) plumes in groundwater, produced from a gasoline spill that contains ethanol. Ethanol has a potential negative impact on the natural biodegradation of BTEX compounds in groundwater. The primary objective of the software is to predict the increase in surface area of the plume of BTEX compounds or any other chemical of concern (COC) due to the presence of ethanol in groundwater.
- Modular 3-D Multi-Species Transport Model for Simulation of Advection, Dispersion, and Chemical Reactions of Contaminants in Groundwater Systems (MT3D)
MT3D is a 3D solute transport model for simulation of advection, dispersion, and chemical reactions of dissolved constituents in ground-water systems. The model uses a modular structure similar to that implemented in MODFLOW. The modular structure makes it possible to independently simulate advection, dispersion, sink/source mixing, and chemical reactions without reserving computer memory space for unused options.
- Multimedia Exposure Assessment Model (MULTIMED)
MULTIMED is a one-dimensional, steady-state model used to predict the concentration of contaminants migrating from a waste disposal facility via the subsurface, surface water, and air pathways to receptor sites.
- Nonaqueous-Phase Liquid (NAPL) Simulator
NAPL Simulator conducts a simulation of the contamination of soils and aquifers that results from the release of organic liquids commonly referred to as nonaqueous-phase liquids (NAPLS). The simulator is applicable to three interrelated zones: a vadose zone that is in contact with the atmosphere, a capillary zone, and a water-table aquifer zone.
- Remediation Evaluation Model for Chlorinated Solvents (REMChlor)
REMChlor is an analytical solution for simulating the transient effects of groundwater source and plume remediation. In the analytical method, the contaminant source model is based on a power-function relationship between source mass and source discharge, and it can consider partial source remediation at any time after the initial release.
- Remediation Evaluation Model for Fuel hydrocarbons (REMFuel)
REMFuel simulates the transient effects of groundwater source and plume remediation for fuel hydrocarbons. In the analytical method, the contaminant source model is based on a power function relationship between source mass and source discharge for multiple fuel constituents, and it can consider partial source remediation at any time after the initial release.
VLEACH is a one-dimensional, finite difference model for making preliminary assessments of the effects on groundwater from the leaching of volatile, sorbed contaminants through the vadose zone. The program models four main processes: liquid-phase advection, solid-phase sorption, vapor-phase diffusion, and three-phase equilibration.
HELP is a quasi-two-dimensional modeling program that simulates water movement into and out of landfills based on a waste management system's particular design. The user can conduct water-balance analyses of solid waste disposal and containment facilities.
- Environmental Geophysics
The Environmental Geophysics database contains information on geophysical methods, references to geophysical citations, and a glossary of geophysical terms related to environmental applications.
- Supercomputer for Model Uncertainty and Sensitivity Evaluation (SuperMUSE)
SuperMUSE enhances quality assurance in environmental models and applications. With SuperMUSE, EPA can now better investigate new and existing uncertainty analysis (UA) and sensitivity analysis (SA) methods. EPA can also more easily achieve UA/SA of complex, Windows-based environmental models, allowing scientists to conduct analyses that have, to date, been impractical to consider.
- Biota Sediment Accumulation Factor Data Set (BSAF)
BSAF is a data set of approximately 20,000 biota-sediment accumulation factors from 20 locations (mostly Superfund sites) for nonionic organic chemicals, e.g., PCBs, PCDDs, PCDFs, DDTs, PAHs, and pesticides. Fresh, tidal, and marine ecosystems are included in the data set, and species in the data set include fish and benthic species (e.g., lobster, crayfish, and benthic invertebrates). The purpose of the data set is fivefold:
- Provide tools for evaluating the reasonableness of BSAFs from other locations,
- Provide a tool for building a BSAF data set for locations of your interest,
- Provide data for performing bounding assessments of risks for locations where limited or no bioaccumulation are available,
- Permit inquiry into underlying relationships and dependences of BSAFs upon ecosystem conditions and parameters, and
- Allow comparison of PCB, PCDD, and PCDF residues to residue-effects data download from PCBRes .
ECOTOX summarizes in vivo toxicity of individual chemicals to aquatic and terrestrial organisms; to be incorporated into larger toxicology databases.
Research question: How can I find data to help assess the toxicity of chemicals to aquatic life, terrestrial plants and wildlife?
PCB Residue Effects Database (PCBRes)
The PCBRes database to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic effects. The purpose is to develop PCB critical residue values for fish, mammals and birds, especially as these relate to aquatic and aquatic-dependent species. This database also includes expression of critical residue values based upon PCB Aroclors and total PCB-based congener specific methods because PCBs occur as complex mixtures.