Course Catalog

Introduction and Use of the Comprehensive Aquatic System Model (CASM)

Models are increasingly being utilized for the purposes of ecological risk assessment; one important objective of this course is to increase the accessibility and use of the CASM in support of field. The model has been in the peer-reviewed literature since 1989, with recent publications on atrazine risk assessment in 2013 and 2015. Prior to this short course, the model has been held close by its originator (Bartell). It is hoped that this course will provide an avenue for increasing the availability to, and familiarity of, environmental scientists, risk assessors, and risk managers with the CASM and correspondingly increase the application of the model by freely disseminating a copy to course participants. The course is unique in providing an ecologically realistic context (e.g., food web and ecosystem modeling) for extrapolating the results of routine toxicity tests to assess risks posed by pesticides (and other potentially toxic chemicals) – the course goes beyond simple ratios of exposure concentrations to toxic benchmark values (risks quotients).

Course Details

Key Topics

What are the 5-7 key topics your course will cover:

  • Basic structure and function of the CASM
  • Basic review of ecological risk assessment and standard toxicity testing for pesticides
  • Derivation of toxicity and other data required to set up and execute pesticide risk assessments using the CASM
  • Interpretation of CASM results: direct and indirect effects, effects on modeled populations, communities, and ecosystem
  • CASM numerical sensitivity and uncertainty analysis


The Comprehensive Aquatic System Model (CASM) is a bioenergetics-based aquatic food web and ecosystem model that has been developed to estimate ecological risks posed by pesticides (and other potentially toxic chemicals). The course will describe the CASM in detail. Model structure, process formulations, parameterization, and outputs will be presented and discussed. The course will present example case studies of ecological risk assessments performed using the CASM. The strengths, limitations, and sensitivity of the model will be described. Participants will receive hands-on experience in setting up CASM applications for ecological risk assessment of pesticides. Participants will receive a complimentary version of the CASM upon completion of the course.

Who Should Attend

  • Ecological risk assessors in industry, government, and academia
  • Risk managers, particularly in the agrochemical business
  • Mid-level government administrators with responsibilities in risk assessment
  • Environmental consultants with an interest in ecological modeling and risk assessment


  • Attendees will learn in detail about the capabilities of the CASM for describing aquatic food web and ecosystem dynamics with an emphasis on applications to ecological risk assessment
  • Attendees will be introduced to the challenges in using routinely performed toxicity test results to assess risks in complex ecological systems
  • Attendees will gain hands-on experience with a flexible modeling framework for assessing ecological risk, with an emphasis on pesticide risk assessment
  • Attendees will experience the opportunity to think about applications of the CASM beyond ecological risk assessment, for example, ecosystem management and restoration
  • Attendees will leave the course with a working version of the CASM that can be applied and adapted to address challenges in basic ecosystem science, as well as environmental assessment


  1. Course Introduction and Brief History of Ecological Modeling
  2. Review of Current Ecological Risk Assessment Practice/Guidelines
  3. Review of Standard Toxicity Tests for Aquatic Organisms
  4. Description of the Comprehensive Aquatic System Model (CASM)
    • Modeling objectives
    • Model structure
    • Process formulations
    • Modeling toxic effects (lethal, sublethal) in the CASM
    • Data requirements and sources
    • CASM execution
    • Description of CASM outputs
    • CASM sensitivity and uncertainty analysis
  5. Case Study CASM Applications in Pesticide Risk Assessment
  6. Attendee Hands-on practice with the CASM
  7. Questions and Discussion with Attendees
  8. Attendees provided with USB drives with CASM software, user manual, selected peer-reviewed CASM articles, and course lecture materials

Course Locations




  Member Non-Member
Advanced $495 $550
Standard $550 $650

About the Instructor

  • Dr. Steven M Bartell

    offers 30-plus years of professional experience in the development, application, and analysis of ecological models. He was a senior research scientist at the Environmental Sciences Division, Oak Ridge National Laboratory (1980-1992) and the Institute of Ecology, University of Georgia (1978-1980).