Ecosystem Research at a Glance
AQUATOX AQUATOX is an aquatic simulation model that Richard A. Park and Jonathan S. Clough of EcoModeling developed for EPA. AQUATOX simulates the transfer of biomass, energy and chemicals from one compartment of the ecosystem to another. It does this by simultaneously computing each of the most important chemical or biological processes for each day of the simulation period; therefore it is known as a process-based or mechanistic model. AQUATOX can predict not only the environmental fate of chemicals in aquatic ecosystems, but also their direct and indirect effects on the resident organisms, such as fish, invertebrates and aquatic plants.
Abiotic Reductive Transformations Reductive transformation is the dominant reaction pathway for many organic pollutants in anoxic environments. Although there have been significant advancements in the understanding of the classes of organic chemicals that are subject to reduction in anoxic environments, it is not yet possible to predict the rates of reductive transformations quantitatively. Consequently, models used in regulatory decision-making do not incorporate this reaction pathway. The goal of the project is to develop useful predictive models that describe the reaction kinetics for the reductive transformation of organic chemicals in anoxic environments.
BASS BASS simulates the population and bioaccumulation dynamics of age-structured fish communities. BASS was developed to investigate the bioaccumulation of chemical pollutants within a community or ecosystem context, However, it can also be used to explore population and community dynamics of fish assemblages that are exposed to a variety of nonchemical stressors. These stressors include altered thermal regimes associated with hydrological alterations or industrial activities, commercial or sports fisheries, and introductions of non native or exotic fish species.
EPA's Collaboration with the Canaan Valley Institute To address aquatic ecosystem management and restoration, the Canaan Valley Institute (CVI, a nonprofit outreach organization) and EPA will collaborate in adding to the existing GIS/modeling tools (Landscape Analyst, Highlands Profiler, REVA web tool).
Chiral Chemistry: the ultimate in pollutant speciation What's in a molecule? We ordinarily thinka diagram of molecular structure shows everything about the way atoms connect to make a specific chemical with defined properties. However, with some molecules, a careful look at their three dimensional structure offers a surprise.
Chemical Property Values Partitioning of chemicals between environmental media (water, air, soil) are partly determined by properties of the chemicals. Values of these properties can be obtained from the scientific literature that reports on measured values. Since there are a wide range of environmental conditions of interest (especially temperature and pH), there are often no suitable literature values available. In these cases, a variety of methods can determine estimated parameters.
What is in Our Drinking Water? Identification of New Chemical Disinfection By-products (DBPs) What is a DBP? A drinking water disinfection by-product (DBP) is formed when the chemical used for disinfecting the drinking water reacts with natural organic matter and/or bromide/iodide in the source water. Popular disinfectants include chlorine, ozone, chlorine dioxide, and chloramine. Source waters include rivers, lakes, streams, groundwater and sometimes seawater. We have only known about DBPs since 1974, when Rook identified chloroform as a DBP resulting from the chlorination of tap water. Since then, hundreds of DBPs have been identified in drinking water.
Environmental Fluid Dynamics Computer Code (EFDC) EFDC can simulate water and water quality constituent transport in geometrically and dynamically complex water bodies, such as vertically mixed shallow estuaries, lakes and coastal areas. The EFDC model solves the three-dimensional, vertically hydrostatic, free surface, turbulent averaged equations of motion for a variable density fluid. The model uses a stretched, or sigma, vertical coordinate and Cartesian, or curvilinear, orthogonal horizontal coordinates.
Exposure Analysis Modeling System (EXAMS) EXAMS allows for the development of general aquatic ecosystem models for the rapid evaluation of the fate, transport, and exposure concentrations of synthetic organic chemicals, including pesticides, industrial materials and leachates from disposal sites. EXAMS also has an integrated database management system for the storage and management of information required by the software. EXAMS summarizes critical output for aid in ecological risk assessments.
Framework for Risk Analysis of Multi-Media Environmental Systems (FRAMES) EPA develops, implements, and enforces regulations that protect human and ecological health from myriad chemical and non-chemical stressors that human activities impose on the environment. Fundamental to the execution of these regulations is a need to understand the environmental processes (physical, biological and chemical) that collectively release, transform and transport contaminants resulting in exposure and a probability of deleterious health effects. Computer models are key tools for organizing the knowledge of environmental science for application in the decision making process.
Helping Green Turtles Through Water Quality Assessment of Their Critical Habitat Green turtle (Chelonia mydas) populations have been steadily decreasing worldwide. One contributor to their decline is fibropapillomatosis (FP), a viral disease found in these turtles in many locations around the world. The disease causes warts and tumors that spread throughout the turtle’s body. These obstruct internal organs which can interfere with vital functions, or interfere with vision and mobility as large warts develop on the face and flippers. Most of the affected turtles die of starvation, because the tumors and warts impede swimming and foraging. Many turtles are also harmed by secondary bacterial infections that develop in dying tissues riddled with tumors.
HSPF Toolkit for BMP Modeling Applications This toolkit enables HSPF users to extend the model's application to urban watersheds with sewer system networks and to areas with (BMPs) such as detention basins. It was developed for low impact development modeling applications. The tool simulates BMPs that store stormwater runoff to attenuate flooding and remove pollutants. Presently, the tool is not recommended for simulating infiltration trenches, dry wells or BMPs that require channels which infiltrate.
Multimedia, Multi-pathway, Multi-receptor Exposure and Risk Assessment (3MRA) The primary objective of the research program is to develop, test and apply a multimedia, multi-pathway, multi-receptor exposure and risk assessment modeling system (the 3MRA) and accompanying methodologies to assess uncertainty and activities to support regulatory-based applications.
OnSite on-line calculators OnSite provides modelers and model reviewers with prepackaged tools for performing site assessment calculations. The convenience of the prepackaged calculators helps provide consistency for simple calculations, and access to methods and data that are not commonly available. The latter include data on fuel composition and models for leaching from fuel lenses.
PLUMES Pathogens (bacteria, viruses, and protozoa) pose problems for public waters and beaches. These organisms can cause illness, ranging in severity from rashes, swimmer's itch, throat infections, stomach cramps and nausea to more extreme conditions like cholera, salmonella, typhoid fever or hepatitis A. Economic impacts of closed beaches can be considerable.
Recreational Water Quality Criteria Beach closure and advisories are predicted through multiple linear regression (MLR) models. To provide timely contamination predictions, The Predictive Modeling at Beaches report provides evaluations and suggests improvements for the statistical models that assess recreational water quality.
Supercomputer for Model Uncertainty and Sensitivity Evaluation (SuperMUSE) EPA's Supercomputer for Model Uncertainty and Sensitivity Evaluation (SuperMUSE) is key to enhancing quality assurance in environmental models and applications. Uncertainty analysis (UA) and sensitivity analysis (SA) remain critical, though overlooked steps in the development and evaluation of computer models. While there is high potential for exposure of humans and ecosystems to chemicals released into the environment, the degree to which this potential is realized is often uncertain.
SPARC EPA researchers have developed a predictive modeling system SPARC (Sparc Performs Automated Reasoning in Chemistry), which calculates a large number of physical andchemical parameters from pollutant molecular structure and basic information about the environment (media, temperature, pressure, pH, etc.). The SPARC system has been under development for several years and currently calculates a wide array of physicalandchemical reactivity parameters for organic chemicals. Current and future research involves model refinement andextension to additional properties for organic chemicals, as well as development of this process modeling capability for nutrients and other stressors.
Water Quality Analysis Simulation Program (WASP) WASP is a generalized framework for modeling contaminant fate and transport in surface waters. Its flexible, compartmental approach allows it to address problems in one, two, or three dimensions. Its design allows easy substitution of user-written routines into the program structure. WASP has been used to answer questions regarding biochemical oxygen demand, dissolved oxygen dynamics, nutrients and eutrophication, bacterial contamination, and organic chemical and heavy metal contamination. The current WASP software package includes the scientific modules TOXI, EUTRO, and DYNHYD. TOXI models the transport and transformation of chemicals; EUTRO simulates dissolved oxygen and eutrophication processes; and DYNHYD is a hydrodynamic model used for prediction water flow and volume.
WhAEM2000 Wellhead Analytic Element Model WhAEM2000 is a public domain and open source general purpose ground-water flow modeling system, with strengths in representing regional flow systems, and ground water/surface water interactions. It was designed to facilitate capture zone delineation and protection area mapping in support of the State's Wellhead Protection Programs (WHPP) and Source Water Assessment Planning (SWAP) for public water supply wells in the United States. WhAEM2000 runs on personal computers running Windows (98,2000,NT,XP). WhAEM2000 provides an interactive computer environment for design of protection areas based on radius methods, well in uniform flow solutions, and geohydrologic modeling methods.