As an applicant, you will already have significant experience in environmental risk assessment (ERA). You may wish to use information below to develop a study plan.

Review the list of the exam Domains and Subdomains. Note the keywords and concepts and the expected levels of understanding associated with each. Levels of understanding range from simple recognition to complex integration and are listed below in order of increasing complexity. The first word of the subdomain will match one of those listed here, and that will determine the level of difficulty at which the questions in that subdomain are written:

  • Knowledge – Identify, Recognize

  • Comprehension – Differentiate

  • Application – Apply, Demonstrate, Interpret, Utilize

  • Analysis – Distinguish

  • Synthesis – Design, Integrate, Organize

  • Evaluation – Derive, Assess, Estimate, Evaluate

Please look at the keywords in domains/subdomains to help develop your review strategy for the exam. Review at least one key reference book on Ecotoxicology/Environmental Toxicology/ERA (examples are given below). In addition, use the suggested links under Guidance below to improve your familiarity with your keyword list as you see fit.

Books

Use key reference books in the topic area of ERA, as needed, to refresh your knowledge on any of topics in the domains/subdomains. This is not a comprehensive listing of relevant books and you may rely on others sources, as needed.

Guidance

Use the following links, as needed, to refresh your knowledge on any of the topics in the domains/subdomains. You may have other sources to consult, use them.

Example Questions

DOMAIN 6 (Supra-organism level ecotoxicology), Subdomain 5 (Evaluate indirect effects on populations, meta-populations, communities, and ecosystems).

You have been criticized that your laboratory dose-response toxicity test (to determine the lethal dose   of copper to Daphnia [water flea], crustacean) is a test of individual response, not a population   response.  What laboratory work would address this?​

  1. Develop a food web model for your species​
  2. Rerun your test with many different species to develop a species sensitivity curve​
  3. Rerun your test with additional endpoints to develop a Leslie matrix​
  4. Identify policies that state your test does apply to populations

DOMAIN 1: Environmental risk assessment concepts, principles, and legislative frameworks; A. Differentiate between the components of the risk assessment paradigm: hazard – exposure – risk

Difficulty level = Low

A new chemical formulation was evaluated to determine if it could be an acceptable replacement for a formulation currently in use that was considered to result in environmental harm. The toxicity (human, aquatic, terrestrial), was determined for the components of the formulation, but exposure was not determined. What BEST describes this type of evaluation/assessment?

  1. Risk assessment
  2. Hazard assessment
  3. Exposure assessment
  4. Probability assessment

DOMAIN 2: Fate and behavior of chemicals; A. Assess environmental conditions, processes, and chemical properties driving chemical fate, behavior, and transport 

Difficulty level = Hard

A chemical that is known to volatilize is discharged to a river. The chemical is also known to reversibly sorb to particulate matter suspended in the water column. Which graph illustrates the expected longitudinal profile of the chemical’s concentration in whole water samples with downstream distance in the river?

  1. image a
  2. image b
  3. image c
  4. image d

DOMAIN 4: Sub-organism level ecotoxicology; B. Identify the influence of chemical and organismal properties and environmental conditions on ADME

Difficulty level = Medium

As a general rule, the group that is most likely to pass through the blood-brain barrier is:

  1. divalent metals.
  2. lipophilic chemicals.
  3. hydrophilic chemicals.
  4. pathogens.

DOMAIN 4: Sub-organism level ecotoxicology; D. Assess the utility and limitations of toxicity pathways, mode of action, and/or adverse outcome pathways

Difficulty level = Low

The main purpose of adverse outcome pathway models is to serve as a tool for:

  1. ranking the toxicity of different chemicals.
  2. organizing information on biological mechanisms.
  3. calculating a risk quotient.
  4. supporting probabilistic risk assessment.

DOMAIN 5: Organism-level ecotoxicology; B. Apply concepts of mixture toxicity (e.g., dose additivity, concentration addition vs independent action, kinetics)

Difficulty level = Medium

The most appropriate method to assess bioaccessibility of an organic chemical present in the sediments of a contaminated site to resident benthic organisms is to evaluate the:

  1. Total concentration in bulk sediment (including porewater)
  2. Freely dissolved concentration in porewater
  3. Total extractable concentration in sediment
  4. Organic carbon normalized concentration in sediment

DOMAIN 5: Organism-level ecotoxicology; C. Distinguish variation of sensitivity between individuals and between species

Difficulty level = Hard

In a mesocosm, the effect of a stressor on abundance of alga was recorded. A duration of at least 8 weeks is necessary to demonstrate recovery (lack of recovery is the adverse effect). If the NOEC is based on recovery, what will be the most suitable conclusion for setting Effect Concentrations?

  1. The NOEC could be set at 0.1 mg/L given that no statistical difference was seen after 20 days till the end of the experiment.
  2. The NOEC could be set at 1 mg/L given that no statistical difference was seen at the end of the experiment.
  3. The LOEC (Lowest Observable Effect Concentration) is 0.01 mg/L.
  4. The LOEC is 5 mg/L as no difference from the control was seen at the end of the experiment.

DOMAIN 7: Chemical, biological, and ecological monitoring of exposure and effects; E. Apply biosensor and in-situ exposure data

Difficulty level = Medium

What method would be MOST accurate for estimating soil lead exposure to a ground-feeding bird species?

  1. Collect soil samples, analyze for lead, and construct a food web model
  2. Measure lead in food items from the field
  3. Collect plasma from the bird species and analyze it for lead concentration
  4. Investigate for evidence of neurotoxicity in a bird species from the field

DOMAIN 8: Statistics and modelling in ecotoxicology and environmental risk assessment; F. Derive and assess dose-response metrics and level of confidence (e.g., benchmark dose, LOEC, NOAEL, LC50) 

Difficulty level = Medium

The first figure is a plot of 5% effect concentrations for 13 freshwater species and the second figure is the results for one of those species. Based on the figures, which of the following statements is best supported?

  1. There is minimal risk to algae at copper concentration of 1000 ug/L
  2. There is minimal risk to aquatic organisms at 50 ug/L
  3. A LOEC cannot be estimated from the figure of 13 species
  4. The data shown for the single species are likely from a fish toxicity experiment

Questions or Comments?