2.0 Literature Review
2.1 General Model Review
2.2 Exposure & Impact Review
2.2.1 Reference List
2.2.2 Exposure Models
2.2.3 Exposure Databases
2.1 Models and Databases Lists and Descriptions
This section provides a general review of models, databases, and algorithms that are readily available via the Internet. The review included all types of models, databases, and algorithms required for detailed micro-environmental modeling. The following section (Section 2.2 - Exposure and Impact Review) provides a detailed review of Models and Databases associated with Exposure and Impact Components of the CCEF.
The list of Models and Databases considered for the four scenarios is found below.
Models
Databases
Descriptions of Models and Databases listed in ACC Project Scope of Work
Framework Risk Assessment and Methods
3MRA - Multimedia, Multi-pathway, Multi-receptor Exposure and Risk Assessment:
A risk-based strategy was developed to generate constituent-specific exemption levels for low- risk solid wastes as part of USEPA's Hazardous Waste Identification Rule (HWIR). The 3MRA framework is designed to perform multiple site-based risk assessments by considering the various types of land-based waste management units as the source of contaminants and computes the exposures and the resulting national-scale statistical distributions of human and ecological risks. The regional site-based risk assessments are conducted with an Ni ^ Nf realizations of exposure scenarios, where Ni is the number of Monte-Carlo iterations and Nf is the number of sampled facilities associated with that type of waste management unit.
In each Monte-Carlo realization, fate-and-transport and exposure-and-risk analyses are conducted for the human and ecological receptors at a given site. For a given chemical and a given waste management unit type, the process is repeated for a number of concentrations in the waste of the chemical within the possible chemical concentration range. The methodology is an extension of a regional site-based approach, which accounts directly for correlations between model parameters and utilizes data from actual waste sites across the U.S. The methodology is highly flexible and allows the aggregation of nationwide distributions of risks and the uncertainty in the risks. The querying of risk results yields the regulatory exemption levels based on several types of protection criteria.
A two-dimensional Monte-Carlo simulation procedure is utilized which allows the separation of variability and uncertainty in the risk assessment and the quantification of uncertainty associated with the estimates of protection measures. The results of the Monte-Carlo simulations are compiled in the forms of risk matrices that are queried to determine regulatory exemption levels that meet specified protection levels with specified levels of confidence. Preliminary risk calculations based on a selected pathway (groundwater) are discussed. (Saleem, et al., 1999)
http://www.epa.gov/
APAC, a DOE sponsored program, developed a very detailed analysis of the technical strengths/weaknesses of computer models for the following 6 areas of consequence assessment: chemical & radiological source term generation, fire analysis (inside and outside), in-facility transport, ex-facility chemical transport, ex-facility radiological transport, and energetic events (e.g. explosions, deflagrations, etc.). Many of these groups, including ex-facility chemical, evaluated and compared the codes against test problems. Hundreds of chemical dispersion codes were screened and 23 were evaluated with 13 of the codes involved in test problem evaluation (CALPUFF and INPUFF included).
ARAMS - Army Risk Assessment Modeling System:
ARAMS is based on a widely accepted risk paradigm that integrates exposure and effects assessments to characterize risk. ARAMS is a computer-based decision support system that integrates multimedia fate/transport, exposure, intake/uptake, and the effect of military relevant compounds, explosives, and depleted uranium to assess human and ecological probabilistic risks. ARAMS incorporates various existing databases and models for exposure, intake/update, and effects (health impacts) into a conceptual site modeling framework. With ARAMS, the user has the flexibility to visually specify, through objects, multimedia pathways and risk scenarios. Also, the user can choose which particular model or database to use for each object. Thus, the heart of ARAMS is the object-oriented Conceptual Site Model (CSM). The CSM is based on the Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES) developed by Pacific Northwest National Laboratory (PNNL) of the U.S. Department of Energy (DOE) in cooperation with the U.S. Environmental Protection Agency (EPA).
http://www.wes.army.mil/el/arams/intro.html
CEAM:
Environmental Protection Agency's (EPA) Center for Exposure Assessment Modeling (CEAM) (part of Office of Research and Development) CEAM distributes environmental simulation models and databases for urban and rural nonpoint sources, conventional and toxic pollution of streams, lakes and estuaries, tidal hydrodynamics, geochemical equilibrium, and aquatic food chain bioaccumulation. The most relevant models for exposure work are:
- Exposure Analysis Modeling System (EXAMS): evaluates the fate, transport, and exposure concentrations of synthetic organic chemicals.
- Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES), Hazardous Waste Identification Rule (HWIR) model: screening-level risk-based assessment of potential human and ecological health risks resulting from long term (chronic) exposure to HWIR chemicals released from land-based waste management units (WMUs) containing currently listed waste streams.
- Multimedia Contaminant Fate, Transport, and Exposure Model (MMSOILS) estimates the human exposure and health risk associated with releases of contamination from hazardous waste sites.
EPA National Exposure Research Laboratory, Atmospheric Science Modeling Division .
http://www.epa.gov/asmdnerl/modeling.html
DIAS - Dynamic Information Architecture System:
DIAS is a software framework intended to facilitate the holistic management of information processes, including the construction of federation simulations from component models according to a user-supplied context. These processes are modeled in DIAS as interrelated actions caused by and affecting the collection of diverse objects - which may range from abstract concepts represented by a simulation, through data sets to real world objects, and to input from simulators. The domain of DIAS is flexible, determined by the objects available within DIAS and by the collection of models and other data processing applications which have been gathered by users to address specific information processing concerns.
http://www.dis.anl.gov/DEEM/DIAS/diaswp.html
FRAMES - Framework for Risk Analysis in Multimedia Environmental Systems:
The FRAMES software was created with many features to aid the user in conducting assessments. These features serve to enhance the user's interaction with the underlying scientific models used in many assessments. Included in these features are items such as a pictorial depiction of the Conceptual Site Model to ensure the transfer of the user's idea of the analysis flow of contamination to the modeling scenario correctly. The drag-and-drop environment enables the user to quickly diagram a contaminant flow and, therefore, communicate that image to others (i.e. stakeholders, clients, and other assessment team members). Another timesaving feature is the use of online help. FRAMES has the ability to encompass many different environmental models.
A feature designed to aid in quick results assessment and document preparation is the ability to graphically view data at multiple points throughout the analysis. The FRAMES software has been modularized based on media to allow users to view data before and after each media of interest. The FRAMES platform is a key tool that can be used effectively to analyze environmental contaminant scenarios, benchmark models, and communicate scenarios and results to decision-makers, regulators, and the public. (Gelston, et al., 1998)
http://mepas.pnl.gov:2080/earth/
GoldSim:
GoldSim is a powerful and flexible platform for visualizing and dynamically simulating nearly any kind of physical, financial or organizational system. This software offers the power, flexibility and usability necessary to efficiently deal with the complex issues associated with real-world systems. In this sense, real world systems a) involve multiple interacting components and sub-systems, b) are uncertain, and c) include both continuous (gradual) processes and discrete (sudden) events.
The unique capabilities of GoldSim make it an ideal simulation tool for a wide variety of real-world applications such as Strategic Planning, Portfolio Management, Program Planning, Risk Management, Supply Chain Management, Environmental Modeling, and Engineered Systems Modeling.
http://www.goldsim.com/home/home.asp
HWIR - Hazardous Waste Identification Rule:
The Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES), Hazardous Waste Identification Rule (HWIR) technology provides the ability to conduct screening-level risk-based assessment of potential human and ecological health risks resulting from long term (chronic) exposure to HWIR chemicals released from land-based waste management units (WMUs) containing currently listed waste streams. The FRAMES-HWIR model system consists of a series of components within a system framework.
LifeLine ™, Risk*Assessment, Risk*Works:
Three software packages that model exposures to a defined person as they travel through various microenvironments, accounting for 100% of a set determined timeframe. Developed by The LifeLine Group, LifeLine™ is used to determine the aggregate and cumulative doses occurring from agricultural exposures in the home and yard (emphasis on pesticides).
http://www.hrilifeline.org/
MENTOR:
Modeling Environment for Total Risk studies is a framework for the conceptual/theoretical formulation for exposure and dose assessments presented by Georgopoulos and Lioy (1994), and built on EDMAS (Exposure and Dose Modeling and Analysis System) developed at EOHSI.
http://eohsi.rutgers.edu/decm/EMA/
MIMS - Multimedia Integrated Modeling System:
The MIMS project is a problem solving software framework to support ecosystem modeling and environmental health assessment.
http://www.epa.gov/asmdnerl/mims/
http://www.epa.gov/asmdnerl/models3/
MMS - Modular Modeling System:
A Modeling Framework for Multidisciplinary Research and Operational Applications, MMS is developed to enable a user to selectively couple the most appropriate process algorithms from applicable models to create an "optimal" model for the desired application. Where existing algorithms are not appropriate, new algorithms can be developed and easily added to the system. This modular approach to model development and application provides a flexible method for identifying the most appropriate modeling approaches given a specific set of user needs and constraints.
http://wwwbrr.cr.usgs.gov/projects/SW_precip_runoff/mms/
Multi-domain Framework for Integrating Models and Measurements of Multimedia Environmental Contaminants:
Multi-domain Framework for Integrating Models and Measurements of Multimedia Environmental Contaminants is a LBNL work, EPA sponsored. The goal of this project is to develop and apply models to provide a more complete picture of both how human exposure comes about and how precisely it can be quantified for a number of important pollutants. These efforts are being organized around two research components: (1) an indoor/outdoor model for total human exposure to particulate matter (PM); and (2) the development and evaluation of source-to-dose models for persistent pollutants. (T.E. McKone , W.J. Fisk, A.T. Hodgson, R.G. Sextro)
SEDSS - Sandia Environmental Decision Support System:
SEDSS is a tool for decision-makers that provides a basis for quantitative analyses in support of qualitative questions such as "Is the monitor well network adequate?”, "How many samples are enough?” etc.
http://www.nwer.sandia.gov/sedss/smeth.html
SHEDs - Stochastic Human Exposure and Dose Simulation:
A physically based stochastic model, SHEDS has been developed to estimate pesticide exposure and dose to children via dermal residue contact and non-dietary ingestion. Time-location-activity data are sampled from national survey results to generate a population of simulated children. For each child, a sequence of 5 second object contact events is generated probabilistically for every location-activity combination, yielding sequential micro-level activity profiles. These profiles are combined with probability distributions for surface concentrations and exposure factors (e.g., pesticide transfer and removal efficiency, skin surface area contacted) to yield daily time profiles for dermal loading, body burden, and eliminated pesticide metabolite. Population estimates are then generated via Monte Carlo sampling. The SHEDS model has been applied for children aged 0-4 and 5-9 years for six chlorpyrifos application scenarios: broadcast and crack and crevice methods; <1 day, 1-7 day, and 8-30 days post-application. Diary data for 1096 children from the National Human Activity Pattern Survey were combined with videotaped activity data and probability distributions for measured concentrations and exposure factors (based on a literature review). For each application scenario and age group, population estimates of daily eliminated 3,5,6-trichloro-2-pyridinol (TCP), the urinary metabolite of chlorpyrifos, were generated. These modeled results are comparable to measured results from EPA’s National Human Exposure Assessment Survey and other studies following broadcast and crack and crevice applications of chlorpyrifos.
http://www.riskworld.com/Abstract/1999/SRAam99/ab9ab373.htm
TEAHRS:
The aim of the TEAHRS project is to develop and assess methodologies to determine the acute toxicity of inhalation of fluctuating concentrations of hazardous substances as a contribution to the improvement of quantitative risk assessment.
http://www.risoe.dk/rispubl/SYS/ris-r-1208.htm
THERdbASE - Total Human Exposure Risk database and Advanced Simulation Environment:
The THERdbASE is an integrated database and analytical/modeling software system for use in exposure assessment calculations and studies. THERdbASE was developed to provide a collection of frequently used databases and models related to human exposure assessment all in a single software system. Models are conveniently linked to databases, or queried subsets of data, on human activity patterns, U.S. Census data, and related human exposure databases so that an assessment or analysis can be conveniently run.
http://www.epa.gov/nerlesd1/therd/therd-home.htm
TNRCC:
Texas Natural Resources Conservation Commission (TNRCC) model guidelines.
http://www.tnrcc.state.tx.us/permitting/trrp.htm
TRIM - Total Risk Integrated Methodology:
EPA project to develop models and data for assessing the multimedia residual health and ecological risk from pollutants released to air sheds.
http://www.pestlaw.com/calendar/1998/EPA-19980407A.html
ADORA is a unique source characterization and dispersion model for extremely hazardous chemicals in the atmosphere. Existing atmospheric dispersion models do not treat the chemical reactions and thermodynamics satisfactorily. In ADORA, the source characterization for various release scenarios, reacting puff spreading, lift-off and rise, and transient dispersion under practical meteorological conditions are modeled based on engineering principles. The complex interactions of buoyant/heavy cloud turbulent dynamics, multi-phase thermodynamics, and multi-step chemical reactions for various pollutants are included. The accurate treatment of these processes allows the application of the model to realistic release scenarios without being too conservative.
CALMET:
The CALPUFF Modeling System is composed of three basic components: CALMET, CALPUFF, and CALPOST. CALMET includes a diagnostic wind field model containing objective analyses and parameterized treatments of slope flows, valley flows, terrain blocking effects, and kinematic terrain effects, lake and sea breeze circulations, and a divergence minimization procedure. An energy-balance scheme is used to compute sensible and latent heat fluxes and turbulence parameters over land surfaces. A profile method is used over water. CALMET contains interfaces to prognostic meteorological models such as the Penn State/NCAR Mesoscale Model.
CALMET was modified to enable use of vertical profiles of wind and temperature as characterized by the MM4-FDDA (Mesoscale Model-4 with Four-Dimensional Data Assimilation) meteorological model.
CALPUFF:
CALPUFF is a multi-layer, multi-species non-steady-state puff dispersion modeling that simulates the effects of time-and space-varying meteorological conditions on pollutant transport, transformation, and removal. CALPUFF is intended for use on scales from tens of meters from a source to hundreds of kilometers. It includes algorithms for near-field effects such as building downwash, transitional buoyant and momentum plume rise, partial plume penetration, subgrid scale terrain and coastal interactions effects, and terrain impingement, as well as longer-range effects such as pollutant removal due to wet scavenging and dry deposition, chemical transformation, vertical wind shear, over-water transport, plume fumigation, and visibility effects of particulate matter concentrations.
CALPUFF is appropriate for long-range transport (source-receptor distances of 50km to 200km) of emissions from point, volume, area, and line sources. The meteorological input data should be fully characterized with time-and-space-varying three dimensional wind and meteorological conditions using CALMET. The meteorological fields used by CALPUFF are produced by the CALMET meteorological model.
The CALPUFF modeling system has 3 main components: CALMET (a diagnostic 3-D meteorological model), CALPUFF (the transport and dispersion model), and CALPOST (a postprocessing package). Each of these programs has a graphical user interface (GUI). In addition to these components, there are several other processors that may be used to prepare geophysical (land use and terrain) data in many standard formats, meteorological data (surface, upper air, precipitation, and buoy data), and interfaces to other models such as the Penn State/NCAR Mesoscale Model (MM5).
CalTOX - Soil Model:
CalTOX is an innovative spreadsheet model that relates the concentration of an organic chemical in soil to the risk of an adverse health effect for a person living or working on or near the contaminated soil. It computes site-specific health-based soil clean-up concentrations given target risk levels or human health risks given soil concentrations at the site.
http://www.ntis.gov/fcpc/cpn6462.htm
CARES™:
Residential exposure assessment module currently under development by the American Crop Protection Association and infoscientific.com, Inc. with input from a variety of stakeholders. Cumulative and Aggregate Risk Evaluation System (CARES™) will be developed and deployed through a cooperative effort of stakeholders, including government, industry, and environmental groups. CARES™ will utilize currently accepted and other relevant databases to evaluate potential risk from dietary, drinking water, and residential sources. Risks will be calculated deterministically for Tier 1 screening and probabilistically using Monte-Carlo simulation of individuals for higher tier analyses. CARES will allow users to estimate doses and risks from acute, short term, intermediate duration, and lifetime exposures.
http://infoscientific.com/files/concept.pdf
http://alphacares.org/index.htm
CFAST:
CFAST is a zone model capable of predicting the environment in a multi-compartment structure subjected to a fire. It calculates the time-evolving distribution of smoke and fire gases and the temperature throughout a building during a user-specified fire. CFAST is the result of a merger of ideas that came out of the FAST and the CCFM.VENTS development projects at NIST. The organization of the CFAST suite of programs is thus a combination of the two models. Details of the models including algorithm structure, the physics-based equations, assumptions, and variables descriptions are provided in such a way as to permit modification and tailoring of the program to indoor chemical exposure assessment. With this level of detail, researchers not intimately involved in the development of CFAST should be able to add to the model in a straightforward manner. Independent or cooperative efforts to enhance the capabilities of the model are encouraged. Model developers can use this version of the model for open or proprietary additions to the model or as the basis for new models. CFAST is a member of a class of models referred to as zone or finite element models. This means that each room is divided into a small number of volumes (called layers), each of which is assumed to be internally uniform. CFAST is based on solving a set of equations that predict state variables (pressure, temperature and so on) based on the enthalpy and mass flux over small increments of time. These equations are derived from the conservation equations for energy mass, and momentum, and the ideal gas law. Although it may not be all-inclusive, CFAST has demonstrated the ability to make reasonably good predictions. Also, it has been subject to close scrutiny to insure its correctness. Thus it forms a prototype for what constitutes a reasonable approach to modeling fire growth and the spread of smoke and toxic gases.
http://fast.nist.gov/
ChemScreen:
ChemScreen Risk Assessment Software is based on the US Environmental Protection Agency's RMP Offsite Consequence Analysis Guidance document, dated 24 May 1996. The objective of the program is to provide the user with an initial assessment of offsite consequences resulting from the worst-case release of 40 CFR Part 68 specified chemicals.
Cleek and Bunge:
Cleek and Bunge (1993) developed a model to estimate dermal absorption from infinite dose aqueous solutions; very simplified mathematical model with some QSAR capabilities. (White Paper HHEA-3)
COMIS:
COMIS models the air flow and contaminant distributions in buildings. The program can simulate several key components influencing air flow: cracks, ducts, duct fittings, fans, flow controllers, vertical large openings (windows and/or doors), kitchen hoods, passive stacks, and "user-defined components."
COMIS allows the user to define schedules describing changes in the indoor temperature distribution, fan operation, pollutant concentration in the zones, pollutant sources and sinks, opening of windows and doors, and the weather data. The flexible time step implemented in COMIS enables the modeling of events independent of the frequency with which the weather data are provided.
The COMIS air flow calculation is based on the assumption that indoor air flows reach steady-state at each time step. The contaminant transport is based on a dynamic model and has its own time step, based on the time constant of the most critical zone. The two models are coupled. Results for air flows and contaminant levels are reported in terms of tables by COMIS and in graphical form by some of the user-interfaces.
CONSEXPO - CONSumer EXPOsure Model:
CONSEXPO-3 is a multi-route, single-chemical modeling tool for assessing human exposure to chemicals emitted from consumer products. It focuses on non-professional indoor use of consumer products. The exposure routes include inhalation, dermal, and oral. Because of the wide range of exposures associated with consumer products, CONSEXPO defines five dermal loading scenarios, plus one scenario to model dermal exposure to airborne compounds. The five dermal loading scenarios are: 1) Fixed volume scenario assumes that the product is well mixed, 2) Diffusion in product scenario assumes that the product is not well mixed and transport of a chemical compound takes place by means of diffusion, 3) Migration to skin scenario assumes that dermal exposure is a result of migration of product to the skin, 4 and 5) Transfer coefficient scenario and contact rate scenario are similar to the dermal models used in the EPA’s residential SOPs.
http://www.epa.gov/chemrtk/revmodlr.pdf
An Evaluation of the Potential for Use of Existing Exposure Software (or Software Currently Under Development) in a Tiered Approach to the Assessment of Exposures and Risks to Children.
The LifeLine Development Team, 2001. Phase 1 Report: Findings from Literature Search and Review of Modeling Projects Currently Available or Under Development. Prepared for the American Chemistry Council, Comprehensive Chemical Exposure Framework (CCEF) Project (Agreement #1388).
CONTAMW:
CONTAMW is a multi-zone indoor air quality and ventilation analysis computer program designed to help predict airflows, contaminant air concentrations, and personal exposure for buildings.
http://www.bfrl.nist.gov/IAQanalysis/CONTAMWdesc.htm
California Population Indoor Exposure Model (CPIEM):
Developed by GOMET for the California Air Resources Board, CPIEM uses Monte Carlo Simulation to determine distributions of daily time-integrated concentrations of inhalation exposures (and doses) for Californians.
DEPM - Dietary Exposure Potential Model (DEPM):
DEPM is a model and database system that correlates extant food information in a format for estimating dietary exposure. The resident database system includes results from government-sponsored food intake surveys and chemical residue monitoring programs. A special feature of the DEPM is the use of recipes developed specifically for exposure analysis that link consumption survey data for prepared foods to the chemical residue information, which is normally reported for raw food ingredients. Consumption in the model is based on 11 food groups containing approximately 800 exposure core food types, established from over 6500 common food items.
The summary databases are aggregated in a fashion to allow analyst selection of demographic factors such age/sex groups, geographical regions, ethnic groups and economic status. Daily intake is estimated by the model for over 300 pesticides and environmental contaminants. In addition, contributions to total exposure from exposure core food groups and individual exposure core foods can also be estimated.
http://www.epa.gov/nerlcwww/depm.htm
E-FAST - Exposure & Fate Assessment Screening Tool:
E-FAST provides screening-level estimates of the concentrations of chemicals released to air, surface water, landfills, and from consumer products. Estimates provided are potential inhalation, dermal and ingestion dose rates resulting from these releases. Modeled estimates of concentrations and doses are designed to reasonably overestimate exposures for use in screening level assessment.
E-FAST calculates appropriate human potential dose rates for a wide variety of chemical exposure routes. and estimates the number of days per year that an aquatic ecotoxicological concern concentration will be exceeded for organisms in the water column.
EPI Suite:
The EPI (estimation program interface) SuiteTM is a Windows® based suite of physical/chemical property and environmental fate estimation models developed by the EPA’s Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC). These properties are the building blocks of exposure assessment. EPI SuiteTM uses a single input to run the following estimation models: KOWWINTM, AOPWINTM, HENRYWINTM, MPBPWINTM, BIOWINTM, PCKOCWINTM, WSKOWWINTM, BCFWINTM, HYDROWINTM, and STPWINTM, WVOLWINTM, and LEV3EPITM. This suite of models does various fate and transport estimates such as partition coefficients, rat of volatilization, etc..
EXAMS - The Exposure Analysis Modeling System:
EXAMS simulates an aquatic ecosystem tracing the path and behaviour of a toxic pollutant. It has a database of toxic substances and a command-driven interface, which allows for the definition of new substances and for modifiation of the ecosystem definition.
Each water body may be constituted of up to 32 different segments, for each of which the balance of up to 28 different substances may be simulated. The basic phenomena taken into consideration are: accumulation, chemical and biological transformation, and transport. Environmental conditions may be constant (in the short or the long term) or varying monthly. It ma be use to conduct rapid evaluations and error analyses of the probable aquatic fate of synthetic organic chemicals.
EXAMS combines chemical loadings, transport, and transformation into a set of differential equations using the law of conservation of mass as an accounting principle. It accounts for all the chemical mass entering and leaving a system as the algebraic sum of external loadings, transport processes that export the compound from the system, and transformation processes within the system that convert the chemical to daughter products. The program produces output tables and simple graphics describing chemical exposure, fate, and persistence.
FIRIN/FIRAC:
FIRAC estimates radioactive and non-radioactive source terms and predicts fire-induced flows and thermal and material transport within the facilities. It is applicable to any facility with or without ventilation systems. It is a fast-running code with a user-friendly interface and includes source term models for fires.
FIRAC is one of a family of codes designed to provide improved safety analysis methods for the nuclear industry. The basic material transport capability of FIRAC includes estimates of entrainment, convection, deposition, and filtration of material. The interrelated effects of filter plugging, heat transfer, and gas dynamics are also simulated. A ventilation system model includes elements such as filters, dampers, ducts, and blowers connected at nodal points to form networks. A one-dimensional, lumped-parameter zone-type compartment model is incorporated to simulate flow-induced transients within a facility. No spatial distribution of parameters is considered in this approach, but an effect of spatial distribution can be approximated by noding. (Gregory, W.S., et al.,1992)
FIRAC is designed to estimate radioactive and non-radioactive source terms and predict fire-induced flows and thermal and material transport within the facilities. Particular focus is on transport through the ventilation system of these facilities. FIRAC includes a fire compartment module based on the FIRIN computer code, which was developed at Pacific Northwest National Laboratory (PNNL). The FIRIN module calculates fuel mass loss rates and energy generation rates within the fire compartment. It can also calculate the generation rate and size distribution of radioactive particles that become airborne as a result of a fire in a nuclear facility. More recently, a second fire module, based on the CFAST computer code, was added to FIRAC. CFAST was developed by the National Institute of Standards and Technology (NIST) to model fire growth and smoke transport in multi-compartment structures. The new combined code is called FIRAC2.
GASFLOW:
GASFLOW is a computational fluid dynamics model applied to solving internal and external engineering type flows. The code accounts for turbulent mixing, combustion, and chemical kinetics of gases and aerosol species, as well as heat transfer and condensation to walls and structures. It solves the compressible form of the Navier-Stokes conservation equations using the ICED-ALE numerical scheme. It is basically a multi-dimensional (3-D) finite volume field code with the capability to characterize low-speed, buoyancy driven, diffusion-dominated, or chemically reactive and non-reactive flows within a compartment network. It can be used to analyze spatially refined flow phenomena such as circulation patterns; gas stratification; and chemical distribution and kinetics. The code is written in FORTRAN 90 and is configured for UNIX and LINUX workstations.
A technical assessment of building a virtual building model from a core CFD building interior model (such as GASFLOW) is given at the following URL http://eande.lbl.gov/BTP/papers/43006.pdf
GEMS - Geographical Exposure Modeling System:
GEMS is a modernization of OPPT’s older Graphical Exposure Modeling System and PCGEMS tools. GEMS brings together in one system several EPA environmental fate and transport models and some of the environmental data needed to run them. GEMS includes models and data for ambient air, surface water, soil, and ground water and makes the models much easier to use than their stand-alone counterparts. GEMS will have graphics and Geographical Information System (GIS) capabilities for displaying environmental modeling results.
GEMS will have interactive menus to guide the user in selecting models, selecting and organizing data to be used as input to model runs, executing model runs, and presenting model outputs. The menus will also provide user help. The new system will be modular in design so that EPA can easily add other models to the system in the future. GEMS will also have the capability of retrieving some data from EPA Oracle databases, such as the TRIS data in the EPA Envirofacts Data Warehouse.
GENII:
The GENII computer code was developed at Pacific Northwest National Laboratory (PNNL) to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) into updated versions of existing environmental pathway analysis models. The resulting second generation of environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II or GENII). The GENII system was developed to provide a state-of-the-art, technically peer-reviewed, documented set of programs for calculating radiation doses from radionuclides released to the environment. Although the codes were developed for use at Hanford, they were designed with the flexibility to accommodate input parameters for a wide variety of generic sites.
HARVARD VI:
The WPI/Fire Codes are derived from the Harvard Computer Fire Codes. Harvard VI is a control volume code designed for fire analysis, and can be adapted to chemical transport. It has many of the same modeling capabilities as CFAST and can be extended to multi-compartment facilities. Technical reference: Gahm, J.B., 1983. This info was obtained from www.wpi.edu. The website contains more information on the latest version of this model.
HGSYSTEM:
HGSYSTEM is a suite of programs for assessing dispersion of vapor from gas, liquid or 2 phase releases including multi-component mixtures. HGSYSTEM was first assembled to model the release of Hydrogen Fluoride (HF) and ideal gases (Version 1.0), and then extended to include multicomponent mixtures (version 3.0). HGSYSTEM has been developed by Shell Research Ltd with the support and sponsorship of industry groups.
HGSYSTEM/UF6 is a collaborative development of HGSYSTEM by Lockheed Martin Energy Systems and Earth Technology, sponsored by the United States Department of Energy (DOE) to predict the dispersion of the hydrolysis products of Uranium Hexafluoride.HGSYSTEM possesses an advanced near field transport model with a spatial resolution of less than 1 meter. It has modeling options for calculating time-dependent chemical source terms for pressurized liquids and gases, buoyancy-driven flows, and evaporating pools of single or multi-component releases. It is written in FORTRAN 77 and is highly modularized which allows for program modification to address special needs analysis.
http://www.hgsystem.com/hgweb.html
HPV - HPV Exposure Assessment Screening Tool - HPVScreen :
Physical-chemical properties and fate. This component of HPVScreen will define the physical-chemical properties the user will need for use with the models in the other components. This component will also provide the user with the ability to estimate removal of a chemical by wastewater treatment.
Models for screening-level exposure estimates. This component provides modeled screening-level estimates of the concentrations and potential doses of chemicals released to air, surface water, landfills and from consumer products. The estimates are designed to be conservative (i.e. to be on the high end of exposure or even to overestimate exposure).
Multimedia modeling programs. This component of HPVScreen provides the user with easy access to the EQC and Level III programs developed by Trent University. Among other uses, these programs can be used to address the environmental fate and transport endpoint that are part of the U.S. HPV Challenge Program and the OECD SIDS Program.
- A fourth major component, a "Report Generator," will be added over the next year.
- This component will assist the user in completing a standard template for providing exposure information.
- If the user is using one of the models in HPVScreen, many of the data elements in the reporting template will be automatically filled in.
- If the user has monitoring data or exposure estimates from another model, the reporting template will allow the user to use those data as well. In this case, the user will be queried to provide the data needed to complete the template.
- Online guidance for the user will be available.
IA-NBC-HMAS - Indoor Air-Nuclear, Biological and Chemical-Health Modeling and Assessment System:
The Indoor Air Nuclear, Biological and Chemical Health Modeling and Assessment System (HMAS for short) was developed to serve as a health impacts analysis tool for use in addressing these concerns. HMAS is designed to serve as a functional health modeling and assessment system that can be easily tailored to meet specific building analysis needs. IA-NBC-HMAS is a model designed to focus on indoor air (complex buildings). While its original design is to use for counter terrorism and chemical/biological agent attacks, it also has equal applicability for modeling and assessing indoor pollution from natural sources (e.g., building construction materials, process releases, etc.). It is designed to be coupled with both micro and macro ambient models to be able to model both finite indoor concerns and the full picture of ambient and indoor effect from releases either in the building or outside the building that impact indoor air quality.
IAQX - Simulation Tool Kit for Indoor Air Quality and Inhalation EXposure:
IAQX includes a variety of stand-alone simulation programs, including a general-purpose simulation program, VOC emissions from solvent-based indoor coating products, small-scale solvent spills, VOC emissions from diffusion-controlled homogeneous slabs, and indoor particulate matter. IAQX source models can address emission of chemicals from consumer products, building materials, indoor furnishings, and appliances, including dry sources.
http://www.epa.gov/chemrtk/revmodlr.pdf.
An Evaluation of the Potential for Use of Existing Exposure Software (or Software Currently Under Development) in a Tiered Approach to the Assessment of Exposures and Risks to Children.
The LifeLine Development Team, 2001. Phase 1 Report: Findings from Literature Search and Review of Modeling Projects Currently Available or Under Development. Prepared for The American Chemistry Council, Comprehensive Chemical Exposure Framework (CCEF) Project (Agreement #1388).
INPUFF:
INPUFF is a Gaussian puff model, developed by the U.S. EPA. The model is intended for simulating the atmospheric dispersion of neutrally buoyant or buoyant chemical releases. The model allows for a vertically oriented stack (point source) and a release duration that may be either finite or continuous. INPUFF can account for plume rise due to both buoyancy and momentum. In addition, the model can include the effects of stack-tip downwash.
INPUFF allows the user to specify the location and dimension of a receptor grid where concentration estimates will be calculated downwind of the release. To estimate concentrations, the model uses the Pasquill-Gifford dispersion coefficients with modifications to account for initial dispersion and buoyancy-induced dispersion (if applicable) and a user-specified averaging time.
MCCEM:Multi-Chamber Concentration and Exposure Model:
MCCEM estimates average and peak indoor air concentrations of chemicals released from products or materials in houses, apartments, townhouses, or other residences. And it estimates inhalation exposures to these chemicals, calculated as single day doses, chronic average daily doses, or lifetime average daily doses.
MCCEM is a user-friendly software product that estimates indoor air concentrations using a mass balance approach. It maintains a library of residences, containing data on zone or area volumes, interzonal air flows, and whole-house exchange rates and allows its users to tailor their analysis to a particular location, and to model air concentrations in as many as four zones for a given residence. It estimates exposure for periods ranging from 1 hour to 1 year and develops seasonal or annual exposure profiles using a long-term model and offers several different options for dealing with ‘sinks’. A sink is a material (e.g., carpeting, wallboard) that can absorb chemicals from the air; the absorption can be either reversible or irreversible.
MEPAS - Multimedia Environmental Pollutant Assessment System:
The Multimedia Environmental Pollutant Assessment System considers chronic exposure and human health risks resulting from environmental emissions. Physics-based models of contaminant processes in the air, groundwater, and surface water are integrated in a system that considers both chemical and radioactive potential impacts.
The Multimedia Environmental Pollutant Assessment System (MEPAS) software utilizes sophisticated modeling codes to quickly and easily assess risks from activities that could impact human health, such as remediating hazardous waste sites.
The MEPAS software provides physics-based modeling codes for environmental risk assessment. It quickly integrates results from separate models of contaminant behavior in various media (air, soil, ground water, surface water) and for different scenarios, turning a task that could take weeks (or might never be attempted) into a few hours' work.
MEPAS integrates and evaluates transport and exposure pathways for chemical and radioactive releases according to their potential human health impacts (multimedia in this context refers to multiple environmental transport media). MEPAS takes the nontraditional approach of combining all major exposure pathways into a multimedia computational tool for public health impact. MEPAS is a physics-based approach that couples contaminant release, migration and fate for environmental media (groundwater, surface water, air) with exposure routes (inhalation, ingestion, dermal contact, external dose) and risk/health consequences for radiological and non-radiological carcinogens and non-carcinogens.
http://www.epa.gov/asmdnerl/models3/
MMSOILS - The Multimedia Contaminant Fate, Transport, and Exposure Model:
MMSOILS estimates the human exposure and health risk associated with releases of contamination from hazardous waste sites. The methodology consists of a multimedia model that addresses the transport of a chemical in groundwater, surface water, soil erosion, the atmosphere, and accumulation in the food chain. The human exposure pathways considered in the methodology include: soil ingestion, air inhalation of volatiles and particulates, dermal contact, ingestion of drinking water, consumption of fish, consumption of plants grown in contaminated soil, and consumption of animals grazing on contaminated pasture. For multimedia exposures, the methodology provides estimates of human exposure through individual pathways and combined exposure through all pathways considered. The risk associated with the total exposure dose is calculated based on chemical-specific toxicity data.
The methodology is intended for use as a screening tool. It is critical that the results are interpreted in the appropriate framework. The intended use of the exposure assessment tool is for screening and relative comparison of different waste sites, remediation activities, and hazard evaluation. The methodology can be used to provide an estimate of health risks for a specific site. Since the uncertainty of the estimated risk may be quite large (depending on the site characteristics and available data), MMSOILS addresses these uncertainties via Monte-Carlo analysis.
Models-3/CMAQ - Models-3 and Community Multi-scale Air Quality:
OBODM - Open Burn/Open Detonation Model:
pNEM:
PRESTO - Prediction of Radiological Effects Due to Shallow Trench Operations:
The models simulate the transport of radionuclides in air, surface water, and groundwater pathways, and evaluate exposures through ingestion, inhalation, immersion and external exposure pathways.
PROMISE - PRObabilistic Methodology for Improving Solvent Exposure Assessment:
The PROMISE©model can be used to investigate products used in the workplace and the home. PROMISE© can calculate multi-route exposures from dermal, inhalation (indoor or outdoors), and/or ingestion routes of solvent exposure. The source models included in the software are labeled constant concentration, source and ventilation, pure-substance evaporation, open-can evaporation, and wall or floor liquid application and evaporation. The program’s algorithms model the release of solvent from mixtures that change over time.
RISK:
The model uses data on source emissions, room-to-room air flows, air exchange with the outdoors, and indoor sinks to predict concentration-time profiles for all rooms. The concentration-time profiles are then combined with individual activity patterns to estimate exposure. Risk is calculated using a risk calculation framework developed by Naugle and Pierson (1991). The model allows analysis of the effects of air cleaners located in either/or both the central air circulating system or individual rooms on IAQ and exposure. The model allows simulation of a wide range of sources including long term steady state sources, on/off sources, and decaying sources. Several sources are allowed in each room. The model allows the analysis of the effects of sinks and sink re-emissions on IAQ. The results of test house experiments are compared with model predictions. The agreement between predicted concentration-time profiles and the test house data is good.
RESRAD - RESidual RADioactivity:
A soil guideline is defined as the radionuclide concentration in soil that is acceptable if the site is to be used without radiological restrictions. Soil is defined as unconsolidated earth material, including rubble and debris that might be present. These guidelines are based on the following principles: (1) the annual radiation dose received by a member of the critical population group from the residual radioactive material - predicted by a realistic but reasonably conservative analysis and calculated as committed effective dose equivalent - should not exceed 100 mrem/yr, and (2) doses should be kept as low as reasonably achievable, a concept commonly known as ALARA.
Nine environmental pathways are considered: direct exposure, inhalation of particulates and radon, and ingestion of plant foods, meat, milk, aquatic foods, water, and soil.
SCIPUFF - Second-order Closure Integrated Puff:
SES - Subway Environmental Simulation:
Subway Environmental Simulation (SES) model developed by Parsons Brinkerhoff for the DOT
WPEM - Wall Paint Exposure Assessment:
BDBR:
ChemSTEER - Chemical Screening Tool For Exposures & Environmental Releases:
It allows users to select predefined industry-specific or chemical functional use-specific profiles or user-defined manufacturing, processing and use operations. Using these operations and several chemical-specific and case-specific parameters and general models, the ChemSTEER computer program estimates releases and occupational exposures. The methods in ChemSTEER were developed by the EPA Office of Pollution Prevention and Toxics (OPPT); Economics, Exposure, and Technology Division; Chemical Engineering Branch.
E-FAST - Exposure & Fate Assessment Screening Tool:
E-FAST calculates appropriate human potential dose rates for a wide variety of chemical exposure routes. and estimates the number of days per year that an aquatic ecotoxicological concern concentration will be exceeded for organisms in the water column.
GEMS - Geographical Exposure Modeling System:
GEMS will have interactive menus to guide the user in selecting models, selecting and organizing data to be used as input to model runs, executing model runs, and presenting model outputs. The menus will also provide user help. The new system will be modular in design so that EPA can easily add other models to the system in the future. GEMS will also have the capability of retrieving some data from EPA Oracle databases, such as the TRIS data in the EPA Envirofacts Data Warehouse.
GENII:
IA-NBC-HMAS - Indoor Air-Nuclear, Biological and Chemical-Health Modeling and Assessment System:
IEUBK - Integrated Exposure Uptake Biokinetic Model for Lead in Children:
MEPAS - Multimedia Environmental Pollutant Assessment System:
The Multimedia Environmental Pollutant Assessment System (MEPAS) software utilizes sophisticated modeling codes to quickly and easily assess risks from activities that could impact human health, such as remediating hazardous waste sites.
The MEPAS software provides physics-based modeling codes for environmental risk assessment. It quickly integrates results from separate models of contaminant behavior in various media (air, soil, ground water, surface water) and for different scenarios, turning a task that could take weeks (or might never be attempted) into a few hours' work.
MEPAS integrates and evaluates transport and exposure pathways for chemical and radioactive releases according to their potential human health impacts (multimedia in this context refers to multiple environmental transport media). MEPAS takes the nontraditional approach of combining all major exposure pathways into a multimedia computational tool for public health impact. MEPAS is a physics-based approach that couples contaminant release, migration and fate for environmental media (groundwater, surface water, air) with exposure routes (inhalation, ingestion, dermal contact, external dose) and risk/health consequences for radiological and non-radiological carcinogens and non-carcinogens.
MMSOILS - The Multimedia Contaminant Fate, Transport, and Exposure Model:
The methodology is intended for use as a screening tool. It is critical that the results are interpreted in the appropriate framework. The intended use of the exposure assessment tool is for screening and relative comparison of different waste sites, remediation activities, and hazard evaluation. The methodology can be used to provide an estimate of health risks for a specific site. Since the uncertainty of the estimated risk may be quite large (depending on the site characteristics and available data), MMSOILS addresses these uncertainties via Monte-Carlo analysis.
Modeling Benzene Exposures and Absorbed Dose:
Modeling Dietary Exposures to Heavy Metals and Pesticides:
MTHEM - Multi-pollutant Total Human Exposure Model:
PBPK & PBPD - Physiologically Based PharmacoKinetic (PBPK) & Physiologically Based PharmacoDynamic (PBPD):
QSAR Models - Quantitative Structure Activity Relationship:
REHEX - II:
RESRAD - RESidual RADioactivity:
A soil guideline is defined as the radionuclide concentration in soil that is acceptable if the site is to be used without radiological restrictions. Soil is defined as unconsolidated earth material, including rubble and debris that might be present. These guidelines are based on the following principles: (1) the annual radiation dose received by a member of the critical population group from the residual radioactive material - predicted by a realistic but reasonably conservative analysis and calculated as committed effective dose equivalent - should not exceed 100 mrem/yr, and (2) doses should be kept as low as reasonably achievable, a concept commonly known as ALARA.
Nine environmental pathways are considered: direct exposure, inhalation of particulates and radon, and ingestion of plant foods, meat, milk, aquatic foods, water, and soil.
RISC (RISK in webpage): RISC (Risk Assessment Model for Soil and Groundwater Applications):
The present version (3.0) evaluates human health risk only. However the updated RISC model will incorporate both aquatic and terrestrial ecological risk assessment by modeling contaminant concentrations at key receptor areas and comparing these values with specific acceptance criteria. However, in developing the new version, the developers have highlighted particular difficulties associated with modeling the fate and transport of metals in soils.
The main advantages with RISC are that the risk assessment approach (for human health risk assessment) is relatively widely accepted, the model is able to incorporate NZ specific data, and that investigators are relatively familiar with the software.
RISK:
TEM - Total Exposure Model:
Thongsinthusak:
UCSS - Use Clusters Scoring System:
For each chemical in a cluster, UCSS allows the user to enter data indicating the potential for human and ecological exposure and hazard, and the level of U.S. Environmental Protection Agency (EPA) interest. It calculates health and ecological risk or toxicity rating scores for each chemical within a cluster using the information entered and preprogrammed scoring algorithms. UCSS uses individual chemical scores to calculate an overall cluster score, which is an indicator of potential risk for the use cluster. It contains data on nearly 400 use clusters and 4,700 chemicals.
AHS:
ATW - Air Toxics Website:
The assessment includes four steps that look at the year 1996. As of May 2002, the results posted for all four steps include revisions based on input from scientific peer review.
The goal of the national-scale assessment is to identify those air toxics which are of greatest potential concern in terms of contribution to population risk. The results will be used to set priorities for the collection of additional air toxics data (e.g., emissions data and ambient monitoring data).
CARB - California Air Resources Board:
The mission of CARB is to promote and protect public health, welfare, and ecological resources through the effective and efficient reduction of air pollutants while recognizing and considering the effects on the economy of the state.
CHAD - Consolidated Human Activities Database:
Cohne Hubal et al:
She developed and worked with a variety of computational models to describe the simultaneous mass transport and reaction of inhaled gases in the airway lining. This work was part of a larger project (from 1992-1996)designed to reduce uncertainty in risk assessment for inhaled toxicants, and included research in the area of industrial pollution prevention. She developed the framework to evaluate environmental impact of pollution prevention activities which directly relates energy requirements to process air, water and solid waste emissions. The framework can be used to facilitate lifecycle analysis.
CPDB - Carcinogenic Potency Database:
CSFII - Continuing Survey of Food Intakes by Individuals:
EPA’s Child-Specific Exposure Factors Handbook:
In 1997, EPA/ORD/NCEA published the Exposure Factors Handbook (U.S. EPA, 1997b). The Handbook includes exposure factors and related data on both adults and children. OCHP’s recently-issued child-related risk assessment policy and methodology guidance document survey (U.S. EPA, 1999b), highlighted the Exposure Factors Handbook (U.S. EPA, 1997b) as a source of information on exposure factors for children.
EPA Handbook - EPA Exposure Factors Handbook Database:
HazDat:
IRIS - Integrated Risk Information System:
The heart of the IRIS system is its collection of computer files covering individual chemicals. These chemical files contain descriptive and quantitative information in the following categories:
CMAQ modeling system represent the air component to EPA’s MIMS framework. The Models-3 release contains three types of environmental modeling systems meteorological, emission, and chemistry transport. It also includes a visualization and analysis system.
http://www.epa.gov/asmdnerl/models3/index.html
OBODM is intended for use in evaluating the potential air quality impacts of the open burning and detonation (OB/OD) of obsolete munitions and solid propellants. OBODM uses cloud/plume rise dispersion, and deposition algorithms taken from existing models for instantaneous and quasi-continuous sources to predict the downwind transport and dispersion of pollutants released by OB/OD operations.
pNEM is an EPA exposure model for particulate matter, adapted and further developed at UBC for use in Canada to estimate population exposure to particulate matter.
http://hajek.stat.ubc.ca/projects/pnem.html
PRESTO is a computer model for evaluating radiation exposure from contaminated soil layers, including waste disposal, soil cleanup, agricultural land application, and land reclamation.
The models in PRESTO are designed to calculate the maximum annual committed effective dose to a critical population group and cumulative fatal health effects and genetic effects to the general population in several scenarios:
PROMISE© Version 7 is an ongoing modeling project by Silken, Inc., for the Solvents Council of the American Chemistry Council. The software is designed to evaluate exposures and doses from single and multiple uses of products that contain volatile solvents (e.g., adhesives, paints, floor cleaners, etc.). Appropriate activities for modeling include the use of large volumes of solvents (open drums or open tanks), use of an applied product, or from spills.
http://www.epa.gov/chemrtk/revmodlr.pdf.
An Evaluation of the Potential for Use of Existing Exposure Software (or Software Currently Under Development) in a Tiered Approach to the Assessment of Exposures and Risks to Children.
The LifeLine Development Team, 2001. Phase 1 Report: Findings from Literature Search and Review of Modeling Projects Currently Available or Under Development. Prepared for The American Chemistry Council, Comprehensive Chemical Exposure Framework (CCEF) Project (Agreement #1388).
A computer model sponsored by the EPA for calculating individual exposure to indoor air pollutants from sources is presented. The model is designed to calculate exposure due to individual, as opposed to population, activity patterns and source use. The model also provides the capability to calculate risk due to the calculated exposure. RISK is the third in a series of indoor air quality (IAQ) models developed by the Indoor Environment Management Branch of U.S. EPA's National Risk Management Research Laboratory.
http://www.ntis.gov/fcpc/cpn7493.htm
RESRAD is a computer code developed at Argonne National Laboratory for the U.S. Department of Energy to calculate site-specific RESidual RADioactive material guidelines as well as radiation dose and excess lifetime cancer risk to a chronically exposed on-site resident.
SCIPUFF model is a Lagrangian puff dispersion model developed by Titan's ARAP Group that uses a collection of Gaussian puffs to represent an arbitrary, three-dimensional time-dependent concentration. The turbulent diffusion parameterization is based on turbulence closure theory, providing a direct relationship between the predicted dispersion rate and turbulent velocity statistics of the wind field. In addition to the average concentration value, the closure model also provides a prediction of the statistical variance in the concentration field resulting from the random fluctuations in the wind field. The closure approach also provides a direct representation for the effect of averaging time. SCIPUFF has been incorporated into the Defense Threat Reduction Agency's (DTRA) Hazard Prediction and Assessment Capability (HPAC) software. HPAC is utilized for planning and analysis as well as in the field by military personnel to rapidly determine consequences of dispersing chemical, nuclear and biological agents. SCIPUFF has been validated against a number of laboratory and field experiments, demonstrating its usefulness for non-military applications. It has been recommended as an alternative model by the EPA which can be used on a case-by-case basis for regulatory applications. The publicly available version of SCIPUFF is the same version incorporated in HPAC except that the proprietary and developmental features have been disabled. SCIPUFF runs on a PC with a user-friendly Graphical User Interface (GUI).
The WPEM estimates the potential exposure of consumers and workers to the chemicals emitted from wall paint, which is applied using a roller or a brush. WPEM is a user-friendly, flexible software product that uses mathematical models developed from small chamber data to estimate the emissions of chemicals from oil-based (alkyd) and latex wall paint. This is then combined with detailed use, workload, and occupancy data (e.g., amount of time spent in the painted room, etc,) to estimate exposure.
http://www.epa.gov/opptintr/exposure/docs/wpem.htm
Exposure and Impacts (including toxicity models)
A predictive tool used to estimate potential human health risks by describing and quantifying the key steps in the cellular, tissue and organismal responses as a result of chemical exposure.
Chemical Screening Tool For Exposures & Environmental Releases (ChemSTEER) estimates occupational inhalation and dermal exposure to a chemical during industrial and commercial manufacturing, processing, and use operations involving the chemical. It estimates releases of a chemical to air, water, and land that are associated with industrial and commercial manufacturing, processing, and use of the chemical.
E-FAST provides screening-level estimates of the concentrations of chemicals released to air, surface water, landfills, and from consumer products. Estimates provided are potential inhalation, dermal and ingestion dose rates resulting from these releases. Modeled estimates of concentrations and doses are designed to reasonably overestimate exposures for use in screening level assessment.
GEMS is a modernization of OPPT’s older Graphical Exposure Modeling System and PCGEMS tools. GEMS brings together in one system several EPA environmental fate and transport models and some of the environmental data needed to run them. GEMS includes models and data for ambient air, surface water, soil, and ground water and makes the models much easier to use than their stand-alone counterparts. GEMS will have graphics and Geographical Information System (GIS) capabilities for displaying environmental modeling results.
The GENII computer code was developed at Pacific Northwest National Laboratory (PNNL) to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) into updated versions of existing environmental pathway analysis models. The resulting second generation of environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II or GENII). The GENII system was developed to provide a state-of-the-art, technically peer-reviewed, documented set of programs for calculating radiation doses from radionuclides released to the environment. Although the codes were developed for use at Hanford, they were designed with the flexibility to accommodate input parameters for a wide variety of generic sites.
The Indoor Air Nuclear, Biological and Chemical Health Modeling and Assessment System (HMAS for short) was developed to serve as a health impacts analysis tool for use in addressing these concerns. HMAS is designed to serve as a functional health modeling and assessment system that can be easily tailored to meet specific building analysis needs. IA-NBC-HMAS is a model designed to focus on indoor air (complex buildings). While its original design is to use for counter terrorism and chemical/biological agent attacks, it also has equal applicability for modeling and assessing indoor pollution from natural sources (e.g., building construction materials, process releases, etc.). It is designed to be coupled with both micro and macro ambient models to be able to model both finite indoor concerns and the full picture of ambient and indoor effect from releases either in the building or outside the building that impact indoor air quality.
The Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK) attempts to predict blood-lead concentrations (PbBs) for children exposed to lead in their environment. The model allows the user to input relevant absorption parameters (e.g., the fraction of lead absorbed from water) as well as intake and exposure rates. Using these inputs, the IEUBK model rapidly calculates and recalculates a complex set of equations to estimate the potential concentration of lead in the blood for a hypothetical child or population of children (6 months to 7 years of age). The IEUBK model is designed to predict the probable PbB concentrations for children between 6 months and 7 years of age who have been exposed to lead through environmental media (air, water, soil, dust, and diet). Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK) is an EPA model circa 1999. (White Paper HHEA-3)
The Multimedia Environmental Pollutant Assessment System considers chronic exposure and human health risks resulting from environmental emissions. Physics-based models of contaminant processes in the air, groundwater, and surface water are integrated in a system that considers both chemical and radioactive potential impacts.
http://www.epa.gov/asmdnerl/models3/
MMSOILS estimates the human exposure and health risk associated with releases of contamination from hazardous waste sites. The methodology consists of a multimedia model that addresses the transport of a chemical in groundwater, surface water, soil erosion, the atmosphere, and accumulation in the food chain. The human exposure pathways considered in the methodology include: soil ingestion, air inhalation of volatiles and particulates, dermal contact, ingestion of drinking water, consumption of fish, consumption of plants grown in contaminated soil, and consumption of animals grazing on contaminated pasture. For multimedia exposures, the methodology provides estimates of human exposure through individual pathways and combined exposure through all pathways considered. The risk associated with the total exposure dose is calculated based on chemical-specific toxicity data.
Probabalistic model of bezene exposure and absorbed dose applied to 40 million people represented by EPA Region 5 (MacIntosh, 1995).
Chronic (1-yr average) dietary exposure to 11 heavy metals and pesticides for a population of approximately 120,000 US adults (MacIntosh, 1996).
EPA and Stanford model is mainly modeling patterns of exposure to air pollutants (ozone, PM, carbon dioxide).
http://www.riskworld.com/Abstract/1996/SRAam96/ab6aa368.htm
http://www.riskworld.com/Abstract/1996/SRAam96/ab6aa329.htm
A PBPK/PBPD model for humans describes the body as a set of interconnected compartments, or continuous stirred tank reactors. Each compartment can describe either an organ or a tissue. A PBPK/PBPD model is founded on known physiological processes (blood flow rates, tissues volumes, breathing rates, etc.), on chemical-specific processes (partition coefficients, chemical density, metabolic constants, molecular weight, etc.), and on species-dependent processes.
http://www.pnl.gov/eshs/cap/cd/pbpk.html
Quantitative-structure activity-relationships models used to relate chemical structure to the physiochemical parameters that are important to dermal absorption. QSAR studies attempt to model a variety of molecules and predict their activities based upon their structures. Models are built from sets of data referred to as descriptors. Such models, when accurately constructed, allow for the prediction of the activity of other unknown molecules not originally used to construct the model. These methodologies have terrific potential in the field of drug discovery.(White Paper HHEA-3)
Regional Human Exposure Model was developed to estimate the population's exposure to PM concentrations.
http://www.eih.uh.edu/publications/99annrep/rifai.htm
http://www.burningissues.org/abstracts/econstdy.htm
RESRAD is a computer code developed at Argonne National Laboratory for the U.S. Department of Energy to calculate site-specific RESidual RADioactive material guidelines as well as radiation dose and excess lifetime cancer risk to a chronically exposed on-site resident.
RISC is relatively widely established in New Zealand among environmental risk assessors. RISC models the fate and transport of contaminants in steady state and transient modes. The moel is intuitive to use, and relatively simple.
A computer model sponsored by the EPA for calculating individual exposure to indoor air pollutants from sources is presented. The model is designed to calculate exposure due to individual, as opposed to population, activity patterns and source use. The model also provides the capability to calculate risk due to the calculated exposure. RISK is the third in a series of indoor air quality (IAQ) models developed by the Indoor Environment Management Branch of U.S. EPA's National Risk Management Research Laboratory.
The model uses data on source emissions, room-to-room air flows, air exchange with the outdoors, and indoor sinks to predict concentration-time profiles for all rooms. The concentration-time profiles are then combined with individual activity patterns to estimate exposure. Risk is calculated using a risk calculation framework developed by Naugle and Pierson (1991). The model allows analysis of the effects of air cleaners located in either/or both the central air circulating system or individual rooms on IAQ and exposure. The model allows simulation of a wide range of sources including long term steady state sources, on/off sources, and decaying sources. Several sources are allowed in each room. The model allows the analysis of the effects of sinks and sink re-emissions on IAQ. The results of test house experiments are compared with model predictions. The agreement between predicted concentration-time profiles and the test house data is good.
http://www.ntis.gov/fcpc/cpn7493.htm
EPA and US Air Force developed The Total Exposure Model (TEM) to estimate population and individual exposure to waterborne contaminants. TEM models the fundamental physical and chemical processes that occur as individuals are exposed to the contaminated water supply. TEM calculates an individual’s exposure and dose using finite difference techniques, estimating the mass transfer of the chemicals from the water to the air during water use activities (i.e. showering).
Thongsinthusak, et al. (1999) exponential saturation model with lag time to estimate dermal absorption; used for pesticide exposure; model derived from experimental data sets. (White Paper HHEA-3)
Use Clusters Scoring System identifies and screens clusters of chemicals ("use clusters") that are used to perform a particular task. A use cluster is a set of chemicals that may be substituted for one another in performing a given task. It identifies clusters of potential concern and provides an initial ranking of chemicals using human and environmental hazard and exposure data from a number of sources.
The major objective of the Adult Health Study (AHS) was to collect information on the health condition of the atomic-bomb survivors, especially those health issues that are not directly related to death. To do this, about 20,000 subjects selected from the RERF Life Span Study sample of atomic-bomb survivors were followed through biennial health examinations since 1958. About 2,400 Life Span Study participants and 1,000 in-utero-exposed persons have been added to the sample since 1978.
http://www.rerf.or.jp/eigo/titles/ahstitle.htm
As part of EPA's National Air Toxics Assessment, EPA conducted a national-scale assessment of 33 air pollutants (a subset of 32 air toxics on the Clean Air Act's list of 188 air toxics plus diesel particulate matter (diesel PM)).
http://www.epa.gov/ttn/atw
The California Air Resources Board is a part of the California Environmental Protection Agency, an organization which reports directly to the Governor's Office in the Executive Branch of California State Government.
CHAD is a relational database with a graphical user interface that facilitates queries and report generation. It contains databases from previously existing human activity pattern studies, which were incorporated in two forms: (1) as the original raw data and (2) as data modified according to predefined format requirements. The latter involved development of a common activity/location code system, compilation of background questionnaire information, and the application of data quality flags. CHAD is intended to be an input file for exposure/intake dose modeling and/or statistical analysis.
http://www.epa.gov/chadnet1/
Dr. Elaine Cohne Hubal designed studies to evaluate dermal exposure assessment approaches and to collect exposure factor data in support of the Food Quality Protection Act. 1998 - present. Dr. Cohne Hubal worked on the development of a modeling platform to predict contaminant fate and transport of environmental pollutants and to perform exposure assessments in support of the Hazardous Waste Identification Rule in 1996 - 1997.
The Carcinogenic Potency Database (CPDB) is a widely used resource on the results of chronic, long-term animal cancer tests. It provides a single, standardized and easily accessible database that includes sufficient information on each experiment to permit investigations into many research areas of carcinogenesis. Both qualitative and quantitative information on positive and negative experiments are reported, including all bioassays from the National Cancer Institute/National Toxicology Program (NCI/NTP) and experimental results from the general literature that meet a set of inclusion criteria. Analyses of 5152 experiments on 1298 chemicals are presented. For each experiment, information is included on the species, strain, and sex of the test animal; features of experimental protocol such as route of administration, duration of dosing, dose level(s) in mg/kg body weight/day, and duration of experiment; histopathology and tumor incidence; carcinogenic potency (TD50) and its statistical significance; shape of the dose-response curve; author's opinion as to carcinogenicity; and literature citation.
http://potency.berkeley.edu/cpdb.html
Continuing Survey of Food Intakes by Individuals (CSFII) is conducted by US Department of Agriculture (USDA). The results of the survey can be found at http://www.barc.usda.gov
In April, 1997, President Clinton signed an Executive Order to Protect Children from Environmental Health Risks and Safety Risks. The Order requires all federal agencies to address health and safety risks to children, coordinate research priorities on children’s health, and ensure that their standards take into account special risks to children. To implement the President’s Executive Order, EPA established the Office of Children’s Health Protection (OCHP), and offices within EPA increased their efforts to provide a safe and healthy environment for children by ensuring that all regulations, standards, policies, and risk assessments take into account risks to children.
http://www.epa.gov
The Exposure Factors Handbook Database provides a summary of the available statistical data on various factors used in assessing human exposure. This Handbook is addressed to exposure assessors inside the U.S. Environmental Protection Agency as well as outside who need to obtain data on standard factors to calculate human exposure to toxic chemicals. Recommended values are for the general population and also for various segments of the population who may have characteristics different from the general population.
http://www.epa.gov/ncea/exposfac.htm
HazDat, the Agency for Toxic Substances and Disease Registry's Hazardous Substance Release/Health Effects Database, is the scientific and administrative database developed to provide access to information on the release of hazardous substances from Superfund sites or from emergency events and on the effects of hazardous substances on the health of human populations. The following information is included in HazDat: site characteristics, activities and site events, contaminants found, contaminant media and maximum concentration levels, impact on population, community health concerns, ATSDR public health threat categorization, ATSDR recommendations, environmental fate of hazardous substances, exposure routes, and physical hazards at the site/event. In addition, HazDat contains substance-specific information such as the ATSDR Priority List of Hazardous Substances, health effects by route and duration of exposure, metabolites, interactions of substances, susceptible populations, and biomarkers of exposure and effects. HazDat also contains data from the U.S. Environmental Protection Agency (EPA) Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) database, including site CERCLIS number, site description, latitude/longitude, operable units, and additional site information.
http://www.atsdr.cdc.gov/hazdat
The Integrated Risk Information System (IRIS), prepared and maintained by the U.S. Environmental Protection Agency (U.S. EPA), is an electronic data base containing information on human health effects that may result from exposure to various chemicals in the environment. IRIS was initially developed for EPA staff in response to a growing demand for consistent information on chemical substances for use in risk assessments, decision-making and regulatory activities. The information in IRIS is intended for those without extensive training in toxicology, but with some knowledge of health sciences.
http://www.epa.gov/iris
ITER - International Toxicity Estimates for Risk:
ITER is a free Internet database of human health risk values for over 500 chemicals of environmental concern from several organizations worldwide. ITER is the only database that provides this data in a table format that allows side-by-side comparisons of risk values from different organizations. Below the table is a synopsis that includes an explanation for any differences among the organizations' values. ITER provides links to these organizations for more detailed information. ITER currently contains data from Agency for Toxic Substances and Disease Registry (ATSDR), Health Canada, National Institute of Public Health and Environment (RIVM), The Netherlands, US Environmental Protection Agency (EPA), and independent parties whose risk values have undergone peer review.
http://www.tera.gov/iter
NCHS:
NCHS is the Federal Government's principal vital and health statistics agency. Since 1960, when the National Office of Vital Statistics and the National Health Survey merged to form NCHS, the agency has provided a wide variety of data with which to monitor the Nation's health. Since then, NCHS has received several legislative mandates and authorities.
The National Center for Health Statistics (NCHS) is a part of the Centers for Disease Control and Prevention, U.S. Department of Health and Human Services. To meet priority data needs for public health, NCHS works closely with other Federal agencies as well as researchers and academic institutions.
NCHS data systems include data on vital events as well as information on health status, lifestyle, and exposure to unhealthy influences, the onset and diagnosis of illness and disability, and the use of health care. These data are used by policymakers in Congress and the Administration, by medical researchers, and by others in the health community.
http://www.cdc.gov/nchs
NHANES - National Health and Nutrition Examination Survey:
The National Health and Nutrition Examination Survey (NHANES) is a survey conducted by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention. This survey has been designed to collect information about the health and diet of people in the United States. NHANES is unique in that it combines a home interview with health tests that are done in a Mobile Examination Center.
The National Health and Nutrition Examination Survey provides estimates of the health of Americans by examining a sample of people who represent the American population. To accomplish this, medical staff and other professionals travel across the U.S. in specially equipped mobile examination centers.
NHAPS - National Human Activity Pattern Survey:
The National Human Activity Pattern Survey (NHAPS) was initiated to fill a need for updated activity information on a nationwide scale. Several recent exposure field monitoring studies have shown that human activities play a critical role in explaining the variation in human exposure because they impact the frequency, duration, and intensity of exposure to pollutants. Currently, activity pattern data bases with adequate potential pollutant exposure information are available only for a few cities (Cincinnati, Denver, Washington, DC) or a state (California), and only for limited months of the year. The NHAPS, which began in September, 1992, was a two-year probability-based national telephone interview survey of approximately 10,000 persons that is being conducted by the University of Maryland Survey Research Center assisted by the U.S. EPA to ascertain the time, location, and other characteristics of those activities which are most relevant to
estimating pollutant exposure. The survey design, location and activity codes, data examples, and appropriate analyses are described for NHAPS data base. Time-diary data from this survey were designed to provide standardized activity reports which, when made available in early 1995, will be used to refine current human exposure models. Activity diary data have been effectively used in the following types of analyses: descriptive, relational, temporal, and exposure modeling.
NHEXAS - National Human Exposure Assessment Survey:
The National Human Exposure Assessment Survey (NHEXAS) was developed by the Office of Research and Development (ORD) of the U.S. Environmental Protection Agency (EPA) early in the 1990s to provide critical information about multipathway, multimedia population exposure distribution to chemical classes. The first phase consisted of three pilot studies with the objectives of:
- Evaluating the feasibility of NHEXAS concepts, methods, and approaches for the conduct of future population-based exposure studies;
- Evaluating the utility of NHEXAS data for improved risk assessment and management decisions;
- Testing the hypothesis that the distributions of exposure given by modeling and extant data do not differ from the measurement-based distributions of exposure;
- Defining the distribution of multipathway human exposures for a relatively large geographic area;
- Stimulating exposure research and forging strong working relationships between government and non-government scientists.
- NHEXAS began before the enactment of the Government Performance and Results Act (GPRA), which was written to ensure accountability in the use of resources. Thus, we add a "new" objective in the form of a hypothesis: NHEXAS approaches can be used to develop a "GPRA Report Card" on the efficiency of EPA’s regulations to reduce exposure.
NHGPUS - National Home and Garden Pesticide Use Survey:
The National Home and Garden Pesticide Use Survey (NHGPUS) was conducted for EPA during August and September 1990. The purpose was to collect data on the use of pesticides in and around homes in the United States. The study was designed as a national probability-based sample of households, with personal interviews conducted at the participants' residence. The target population in the survey was housing units in the conterminous United States occupied as primary residences (home where a person lives for half the year or more), excluding institutions, group quarters, military reservations, and Native American reservations (Whitmore et al., 1992).
http://www.epa.gov
OEHHA - Office of Environmental Health Hazard Assessment:
The mission of the Office of Environmental Health Hazard Assessment (OEHHA) is to protect and enhance public health and the environment by objective scientific evaluation of risks posed by hazardous substances.
http://www.oehha.ca.gov
RAIS - Risk Assessment Information System:
Risk Assessment Information System (RAIS) website contains risk assessment tools and information. The Risk Assessment Tools include: Risk-Based Preliminary Remediation Goal (PRG) calculations, a Toxicity database, Risk Calculations, and Ecological Benchmarks. The Tools are designed for use at all DOE sites and can be customized for site-specific conditions. The RAIS also includes information, guidance, and risk results applicable to the Oak Ridge Reservation.
http://risk.lsd.ornl.gov/rap_hp.shtml
RTECS® - Registry of Toxic Effects of Chemical Substances:
Registry of Toxic Effects of Chemical Substances (RTECS) from the US National Institute for Occupational Safety and Health (NIOSH) provides toxicological information with citations on over 140,000 chemical substances. These detailed profiles include toxicological data and reviews; international workplace exposure limits; references to US standards and regulations; analytical methods; and exposure and hazard survey data. The data are compiled into substance records for ease-of-use, and updated data is fully integrated.
SRD - Standard Reference Data Group:
The NIST Standard Reference Data Group (SRDG) at NIST has been proving well-documented numeric data to scientists and engineers for use in technical problem-solving research and development. These recommended values are based on data which have been extracted from the world's literature, assessed for reliability, and then evaluated to select the preferred values. These data activities are conducted by scientists at NIST and in university data centers.
The formal existence of the National Standard Reference Data System dates from 1963, when the Federal Council for Science and Technology asked the then-National Bureau of Standards (now NIST) to assume primary responsibility in the Federal Government for promoting and coordinating the critical evaluation of numerical data in the physical sciences. The program was conceived as a decentralized national effort with financial support coming from a variety of government and private sources, but the NBS was responsible for the overall planning and coordination. In 1968 congress provided a specific legislative mandate for the program through passage of Public Law 90-396, the Standard Reference Data Act. This Act details the policy of Congress to make reliable, critically evaluated data compilations available to scientists, engineers, and the general public.
http://www.nist.gov/srd
Superfund Resource Center:
The EPA administers the Superfund program in cooperation with individual states and tribal governments. The office that oversees management of the program is the Office of Emergency and Remedial Response (OERR).
TOMES:
Handling hazardous chemicals is routine in many workplaces. Precautions must be in place to protect workers and to meet regulatory and safety guideline compliance. The TOMES Plus® System offers rapid, easy access to the critical medical and hazard data needed for immediate, effective response to any situation. Whether reducing the risk of injury or determining safe levels of exposure, TOMES Plus databases include treatment guidelines for acute chemical exposures, evacuation procedures, personal protection procedures, and chemical containment and disposal information. General areas unrelated to chemicals such as ergonomics and human health risk assessment are addressed. The System's proprietary and government databases are integrated to ensure quick access to the fully reviewed, referenced information.
The TOMES Plus System is ideal for:
- Industrial hygienists and hazardous waste chemists
- Safety & risk managers
- Fire department personnel
- Environmental engineers and toxicologists
- Occupational health physicians and chief medical officers
TOXNET - Toxicology and Environmental Health Information Program:
The Toxicology and Environmental Health Information Program (TEHIP) is responsible for the Toxicology Data Network (TOXNET®), an integrated system of toxicology and environmental health databases that are available free of charge on the web. The following databases are available for searching via TOXNET: HSDB®, TOXLINE®, ChemIDplus, IRIS , TRI (Toxic Chemical Release Inventory), CCRIS (Chemical Carcinogenesis Research Information System), GENE-TOX, and DART®/ETIC (Developmental and Reproductive Toxicology/Environmental Teratology Information Center).
http://www.nlm.nih.gov
US Census:
http://www.census.gov
USEPA:
USEPA Exposure Models Library - focused on standard models, mainly fate and transport (1996).
http://esm.versar.com/emlimes/emlintro.htm
Identified Processes Lacking a Specified Model
Dust Resuspension:
A Dust Resuspension model was not identified by the research study. This means that a model does not exist, or it is not widely used or published for this process. If this model existed, it would take surface concentrations from house objects estimated by the indoor air transport model (CONTAMW) and estimate the atmospheric emission rates of dust from resuspension. This information would feed back into the indoor air transport model (CONTAMW).
Fuel Spill Frequency & Volume:
A Fuel Spill Frequency & Volume model was not identified by the research study. This means that a model does not exist, or it is not widely used or published for this process. If this model existed, it would take in information related to the fueling of a gasoline-powered lawn mower, lawn trimmer, or automobile.
Mainstream Cigarette Smoke Emission
A variety of Mainstream Cigarette Smoke Emissions models were identified by the research study. However, it is not known if these models can take information related to contaminant inhalation and release by mainstream smoking and estimate the emission rates of contaminants in mainstream smoke indifferent rooms as input to the indoor air transport model (CONTAMW).
Micro-Environmental Air Transport Outdoors:
An Micro-Environmental Air Transport Outdoors model was not identified by the research study. This means that a model does not exist, or it is not widely used or published for this process. If this model existed, it would take emission information related to fueling and painting spills and estimate the outdoor air concentrations that could impact a human. This information could also be used as an outdoor source to the indoor air transport model (CONTAMW).
Paint Spill Frequency and Volume:
A Paint Spill Frequency and Volume model was not identified by the research study. This means that a model does not exist, or it is not widely used or published for this process. If this model existed, it would take information related to indoor painting of walls by a nonprofessional and potential for spills. Output would be number and volume of spills associated with indoor painting of walls.
Partitioning Between Vapor and Particle Phase:
A Partitioning Between Vapor and Particle Phase model was not identified by the research study. This means that a model does not exist, or it is not widely used or published for this process. If this model existed, it would take air concentrations estimated by the indoor air transport model (CONTAMW) and partitions the air concentrations into vapor (gaseous) and particle components. These partitioned air concentrations can then be used by the indoor air transport model (CONTAMW) to provide refined air concentrations for more realistic exposure modeling.
Source Emission from Fueling, Combustion, and Service:
Source Emission from Fueling, Combustion, and Service models were not identified by the research study. This means that such models do not exist or are not widely used or published for this process. If these models existed, they would take information related to the fueling, operation, and maintenance of a gasoline-powered lawn mower, lawn trimmer, or automobile for a typical household. Output would be emission rates of volatile compounds associated with fueling, operation, and maintenance of a gasoline-powered lawn mower, lawn trimmer, or automobile.
VOC Fugitive Emission from Mixing Vessel:
A VOC Fugitive Emission from Mixing Vessel model was not identified by the research study. This means that a model does not exist, or it is not widely used or published for this process. If this model existed, it would take information related to fugutive emission of volatile organic compounds (VOCs) from a mixing vessel and estimate the emission rates of these compounds as input to the indoor air transport model (CONTAMW).
