File: ABSTRACT.TXT EXAMSII Model System Abstract Center for Exposure Assessment Modeling (CEAM) National Exposure Research Laboratory - Ecosystems Research Division Office of Research and Development (ORD) U.S. Environmental Protection Agency (U.S. EPA) 960 College Station Road Athens, Georgia 30605-2700 706/355-8400 ----------------------------------------------------------------------------- Summary The Exposure Analysis Modeling System (EXAMS), first published in 1982 (epa-600/3-82-023), provides interactive computer software for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals--pesticides, industrial materials, and leachates from disposal sites. Exams contains an integrated Database Management System (dbms) specifically designed for storage and management of project databases required by the software. User interaction is provided by a full-featured Command Line Interface (cli), context-sensitive help menus, an on-line data dictionary and cli users' guide, and plotting capabilities for review of output data. Exams provides 20 output tables that document the input datasets and provide integrated results summaries for aid in ecological risk assessments. Exams' core is a set of process modules that link fundamental chemical properties to the limnological parameters that control the kinetics of fate and transport in aquatic systems. The chemical properties are measurable by conventional laboratory methods; most are required under various regulatory authority. When run under the epa's gems or pcgems systems, exams accepts direct output from qsar software. Exams limnological data are composed of elements historically of interest to aquatic scientists world-wide, so generation of suitable environmental datasets can generally be accomplished with minimal project-specific field investigations. Exams provides facilities for long-term (steady-state) analysis of chronic chemical discharges, initial-value approaches for study of short-term chemical releases, and full kinetic simulations that allow for monthly variation in mean climatological parameters and alteration of chemical loadings on daily time scales. Exams has been written in generalized (N-dimensional) form in its implementation of algorithms for representing spatial detail and chemical degradation pathways. This DOS implementation allows for study of five simultaneous chemical compounds and 100 environmental segments; other configurations can be created through special arrangement with the author. Exams provides analyses of Exposure: the expected (96-hour acute, 21-day and long-term chronic) environmental concentrations of synthetic chemicals and their transformation products, Fate: the spatial distribution of chemicals in the aquatic ecosystem, and the relative importance of each transformation and transport process (important in establishing the acceptable uncertainty in chemical laboratory data), and Persistence: the time required for natural purification of the ecosystem (via export and degradation processes) once chemical releases end. Exams 2.97 includes file-transfer interfaces to the PRZM3 terrestrial model and the FGETS bioaccumulation model; it is a complete implementation of Exams in Fortran 90. Documentation The EXAMS users' manual--"EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS II), User's Guide for Version 2.97"--is available as a WordPerfect (version 5.1) document (binary, non-ASCII) within file EXAMS.WPD, as an ANSI text document (non-binary) within file EXAMS.TXT, and as an ASCII text document (non- binary) within file EXAMS.ASC, with all files stored within the DOCUMENT sub-directory. Refer to file READ.ME in the README sub-directory for further information on the storage format and hardware and/or software print/view requirement(s) of these user's manual files. This report covers a period from October 1, 1995 to March 31, 1997 and work was completed as of April 7, 1997. -----------------------------------------------------------------------------