Exposure Assessment Models

Exposure Assessment Models Recent Additions

Listed below are some of the recent additions and updates available on the Exposure Assessment Models Web site maintained by the EPA Center for Exposure Assessment Modeling (CEAM). To receive e-mail notification of additions and updates, you may subscribe to the CEAM discussion listserv.

March 2014

The AQUATOX Ecosystem simulation model version 3.1 has been added to the CEAM site.  AQUATOX is an ecosystem simulation model that predicts the fate of various pollutants, such as excess nutrients and organic chemicals, and their effects on aquatic ecosystems, including fish, invertebrates, and aquatic plants. AQUATOX is a valuable tool for ecologists, biologists, water quality modelers, and anyone who performs ecological risk assessments for aquatic ecosystems. EPA has just released an enhanced version of AQUATOX, Release 3.1, which includes many model interface enhancements and some conceptual model refinements.

December 2013

  • Watershed Management Optimzation Support Tool (WMOST) version 1.0 has been added to the CEAM site.  WMOST is intended to be used as a screening tool as part of an integrated watershed management process such as that described in EPA’s watershed planning handbook (EPA 2008).1 The objective of WMOST is to serve as a public-domain, efficient, and user-friendly tool for local water resources managers and planners to screen a wide-range of potential water resources management options across their watershed or jurisdiction for cost-effectiveness as well as environmental and economic sustainability (Zoltay et al 2010).
  • Published a modification to Virtual Beach version 3.0 (VB3.0).

September 2013

  • Virtual Beach version 3.0 (VB3.0) has been added to the CEAM site.  Virtual Beach facilitates the development of statistical models of pathogen indicator levels at recreational beaches. VB3.0 reads input data from a text or Excel file, assists the user in preparing the data for statistical analysis, and provides three analytical techniques for model development:  multiple linear regression (MLR), partial least squares regression (PLS), and a gradient boosting machine (GBM).  With an integrated mapping component to determine the geographic orientation of the beach, the software can automatically decompose wind/current speed and direction into along-shore and onshore/offshore components.  VB3.0 can produce new variables from sets of variables in the input file (e.g., means, minimums, maximums, differences, sums, products), and it can test an array of transformations on the independent variables to maximize the linearity of the relationship between the response and those independent variables.  In the MLR module, automated censoring of models with a high degree of multi-colinearity occurs during the selection process. The PLS and GBM modules institute 5-fold cross-validation during model development to avoid over specification.  The prediction module of VB3.0 has a direct link to the USGS EnDDaT system to automatically retrieve data for beach sites in the Great Lakes region.

September 2010

  • CEAM has posted a new application, Virtual Beach. Virtual Beach version 2.0 (VB2.0) is a software package designed to construct site specific Multi-Linear Regression (MLR) models for the prediction of pathogen indicator levels at recreational beaches. VB2.0 reads input data from a text file or Excel document, assists the user in preparing the data for a multiple linear regression (MLR) analysis, enables automated model selection using a wide array of possible model evaluation criteria, and provides predictions using a chosen model and new observational data. With an integrated mapping component to determine the geographic orientation of the beach, the software can automatically decompose wind/current speed and direction into along-shore and onshore/offshore components for later analysis. Data can be examined visually using simple scatterplots to gage relationships between the response and independent variables. VB2.0 can quickly produce second-order interaction terms between main effects, and it can also test an array of transformations on the independent variables in order to maximize the linearity of the relationship between the response and those independent variables. The software includes exhaustive and genetic algorithm (GA) search routines for finding the "best" models from a large array of possible choices. Automated censoring of models with a high degree of multicollinearity (large Variance Inflation Factor) occurs during the selection process. Models can be constructed either using previously collected or forecasted environmental data.

August 2010

  • CEAM has posted an updated version of the Watershed Health Assessment Tools Investigating Fisheries (WHATIF). WHATIFv3.1 incorporates an expanded and enhanced toolset that encompasses regional EMAP data of Mobile Bay Estuary, Alabama that extends WHATIF's geographical domain. WHATIFv3.1 incorporates a new general purpose query tool the Database Exploration Tool, with the output being site data records that match the query. Also a new Mobile Bay Fish Assemblage Predictor tool, species relative abundance based, is included in WHATIFv3.1 that allows a user to predict a fish assemblage at a location of interest based on characteristics of that location.

January 2009

  • CEAM has posted an updated version of the Web-based Interspecies Correlation Estimation (Web-ICE) application. The Web-ICE Species Sensitivity Distribution (SSD) modules have been updated to include selection of multiple surrogate species. Web-ICE generates an SSD from the combined estimated toxicity values of all predicted species for all surrogate species (maximum of 25 surrogates), which are use to predict toxicity hazard levels. The modules include a new option to show additional information for each predicted toxicity value, such as surrogate species, degrees of freedom, model R2, p-value, mean square error, cross-validation success rate, and taxonomic distance.

March 2008

  • CEAM has posted an updated Microsoft Excel 2003 based model, SERAFM (Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury). SERAFM is a process-based, steady-state modeling system incorporating a series of process modules that predict speciated mercury concentrations (Hg0, HgII, MeHg, HgT) in water (filtered and unfiltered) and sediments, and total mercury concentrations in fish tissue.
  • Please refer to the release notes for a detailed list of releases and changes.

March 2008

  • CEAM has posted an updated Microsoft Excel 2003 based model, SERAFM (Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury). SERAFM is a process-based, steady-state modeling system incorporating a series of process modules that predict speciated mercury concentrations (Hg0, HgII, MeHg, HgT) in water (filtered and unfiltered) and sediments, and total mercury concentrations in fish tissue.
  • Please refer to the release notes for a detailed list of releases and changes.

March 2008

  • The Bioaccumulation and Aquatic System Simulator (BASS) has been posted on CEAM. BASS is a model that simulates the population and bioaccumulation dynamics of age-structured fish communities.
  • BASS has be used to:
    • investigate the bioaccumulation of chemical pollutants within a community or ecosystem
    • explore population and community dynamics of fish assemblages that are exposed to a variety of nonchemical stressors such as altered thermal regimes associated with hydrological alterations or industrial activities, commercial or sports fisheries, and introductions of non native or exotic fish species.

September 2007

  • An updated version of the U.S. EPA's Wellhead Analytic Element Model, WhAEM2000, has been posted on the CEAM web site. WhAEM2000 for Windows (98/NT/2K/XP), is a groundwater flow model designed to facilitate capture zone delineation and protection area mapping.
  • A detailed list of changes is available in the release notes.

September 2007

  • The Environmental Fluid Dynamics Code (EFDC) has been posted on CEAM. EFDC is a multifunctional surface water modeling system which includes hydrodynamic, sediment-contaminant, and eutrophication components.
  • EFDC has be used to:
    • study high fresh water inflow events in the northern portion of the Indian River Lagoon, Florida
    • model flow through high vegetation density-controlled wetland systems in the Florida Everglades.
    • discharge dilution studies in the Potomac, James and York Rivers.
    • salinity intrusion studies include the York River, Indian River Lagoon and Lake Worth.
    • sediment transport studies include the Blackstone River, James River, Lake Okeechobee, Mobile Bay, Morro Bay, San Francisco Bay, Elliott Bay - Lower Duwamish Waterway, and Stephens Passage.
    • power plant cooling studies include Conowingo Reservoir, the James River and Nan Wan Bay.
    • contaminant transport and fate studies include the Blackstone and Housatonic Rivers, James River, San Francisco Bay, and Elliott Bay - Lower Duwamish Waterway.
    • water quality eutrophication studies include Norwalk Harbor, Peconic Bay, the Christina River Basin, the Neuse River, Mobile Bay, the Yazoo River Basin, Arroyo Colorado, Armand Bayou, Tenkiller Reservoir, and South Puget Sound.

August 2007

  • CEAM has posted an updated version of the Web-based Interspecies Correlation Estimation (Web-ICE). Web-ICE estimates the acute toxicity of a chemical to a taxon (i.e., the predicted species, genera, or family) without test data from the known toxicity of the chemical to a species with test data (the surrogate).
  • WebICE now provides expanded functionality for aquatic taxa models and sensitivity distributions.
  • A JavaScript-enabled web browser is required to operated Web-ICE.

August 2007

  • The EXAMS - PRZM Exposure Simulation Shell (EXPRESS) model has been updated and posted on CEAM. EXPRESS is designed to facilitate a rapid and consistent assessment of aquatic pesticide exposure on a variety of crops. EXPRESS is a joint project of the USEPA Office of Pesticide Programs' Environmental Fate and Effects Division (OPP/EFED) and the USEPA Office of Research and Development (ORD). A detailed list of changes is available in the release notes.

May 2007

  • Web-based Interspecies Correlation Estimation (Web-ICE) has been posted on CEAM. Web-ICE estimates the acute toxicity of a chemical to a taxon (i.e., the predicted species, genera, or family) without test data from the known toxicity of the chemical to a species with test data (the surrogate). ICE models are least square regressions between the surrogate species and the predicted taxa to estimate the toxicity of that chemical to the predicted species, genus or family. Web-ICE replaces the desktop application, ICE. A JavaScript-enabled web browser is required to operated Web-ICE.
  • Web-ICE can be used to:
    • Predict toxicity to wildlife taxa.
    • Generate Species Sensitivity Distributions.

April 2007

  • CEAM has posted a new ecosystem assessment tool, Watershed Health Assessment Tools Investigating Fisheries (WHATIF). WHATIF is software that integrates a number of calculators, tools, and models for assessing the health of watersheds and streams with an emphasis on fish communities in the Mid-Atlantic Highland region. The tool set consists of hydrologic and stream geometry calculators, a fish assemblage predictor, a fish habitat suitability calculator, macro-invertebrate biodiversity calculators, and a process-based model to predict biomass dynamics of stream biota (the BASS model).
  • These models can be used to:
    • Watershed health assessment.
    • Prediction of stream hydraulic geometry based on mean annual flow conditions.
    • Prediction of stream hydraulic geometry based on Bankfull flow conditions.
    • Prediction of fish habitat suitability.
    • Prediction of fish assemblage.
    • Prediction of macro-invertebrate biodiversity (EPT and MBII).
    • Simulation of bio-accumulation.
    • Investigate sensitivity of processes and model parameters.
    • Screening analysis, such as prioritization of areas for restoration and comparison of alternative watershed and habitat management scenarios.

February 2007

  • CEAM has re-posted the 3DFEMWATER/3DLEWASTE models (source code only). 3DFEMWATER/3DLEWASTE, Three-Dimensional Finite Element Model of Water Flow Through Saturated-Unsaturated Media (3DFEMWATER) and Three-Dimensional Lagrangian-Eulerian Finite Element Model of Waste Transport Through Saturated-Unsaturated Media (3DLEWASTE) are related and can be used together to model flow and transport in three dimensional, variably-saturated porous media under transient conditions with multiple distributed and point sources/sinks.
  • These models can be used to apply the assimilative capacity criterion to development of wellhead protection areas. A detailed list of changes is available in the release notes.

October 2006

  • CEAM has posted a new Microsoft Excel 2003 based model, SERAFM (Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury). SERAFM is a process-based, steady-state modeling system incorporating a series of process modules that predict speciated mercury concentrations (Hg0, HgII, MeHg, HgT) in water (filtered and unfiltered) and sediments, and total mercury concentrations in fish tissue.
  • SERAFM was specifically developed to serve as a screening-level tool to investigate mercury cycling and exposure concentrations in water bodies and associated impacted wildlife exposure risk, as well as a research tool to investigate mercury processes within the watershed and water body.

October 2006

  • CEAM has updated the EXPRESS model (EXAMS - PRZM Exposure Simulation Shell). EXPRESS is designed to facilitate a rapid and consistent assessment of aquatic pesticide exposure on a variety of crops. EXPRESS is a joint project of the USEPA Office of Pesticide Programs' Environmental Fate and Effects Division (OPP/EFED) and the USEPA Office of Research and Development (ORD). A detailed list of changes is available in the release notes.

May 2006

  • CEAM has updated the PRZM3. PRZM3 is the most recent version of a modeling system that links two subordinate models, PRZM and VADOFT, in order to predict pesticide transport and transformation down through the crop root and unsaturated zone. A detailed list of changes is available in the release notes.

May 30, 2006

  • CEAM has updated the MINTEQA2 model for use on Windows 2000 and XP computer systems. The MINTEQA2 model and its associated PRODEFA2 software were recompiled and released as version 4.03. Model functionality remains unchanged, however, the system is now compatible with a wider range of Windows operating systems. A detailed list of changes is available in the release notes.
  • A new component database containing Monomethylmercury (MMHg) and Tributyltin (TBT) is also distributed with MINTEQA2 version 4.03. The addition of this new database and accompanying documentation will permit researchers to simulate the aqueous chemical speciation of MMHg and TBT.

April 17, 2006

  • Two models developed by the EPA National Health and Environmental Effects Research Laboratory (NHEERL) are now available through CEAM.
  • The Interspecies Correlation Estimations (ICE) for Acute Toxicity to Aquatic Organisms and Wildlife program was developed to allow prediction of acute toxicity to taxa with limited toxicity databases such as endangered species.
  • The Acute-to-Chronic Estimation (ACE) with Time-Concentration-Effect Models program was developed to allow prediction of chronic toxicity from acute toxicity datasets.

January 10, 2006

  • Hurricane Katrina Modeling Demonstration - EPA and Battelle have a CRADA agreement to attempt to link near-field models, such as the Visual Plumes UM3 model, with large-scale hydrodynamic models, such as Battelle's implementation of the Finite Volume Coastal Ocean Model (FVCOM). This download is a preliminary demonstration of FVCOM applied to flood waters generated by Hurricane Katrina and discharged to Lake Pontchartrain.

Additions and updates on the Exposure Assessment Models Web site prior to 2006 are available.