Environmental Analysis Tools - Environmental Impact Analysis: Process and Methods - page 267

7.2.3 Initial Problem Formulation

There are two basic elements to the initial problem formulation: a conceptual
site model and identification of general ecological endpoints. The conceptual
site model must be developed before the endpoints can be determined, and
this model is the ecological risk assessment equivalent of the environmental
analysis impact prediction conceptual model (see Section 5.3.1). The problem is
defined by tracking sources of contamination to potential ecological receptors
such as fish, birds, and mammal-breeding dens (Figure 7.3). This requires some
background knowledge of the site, including ecological site description, the
history of contamination, and contaminant migration pathways (e.g., ground-
water transport, soil erosion, aerial dispersion, and food chain transfer).
The ecological site description is similar to the initial description of the affected
environment typically prepared as part of the environmental impact analysis
scoping effort (see Section 4.3). It is generally accomplished by an experienced
ecologist conducting a literature review and more importantly a site reconnais-
sance to identify the primary ecosystems and communities present within and
adjacent to the site. It can be considered the applied equivalent of the observa-
tional first step in the scientific method which is to understand the setting before

Primary/
secondary sources

Release mechanisms Migration pathway Receptors

Groundwater f low
to surface waters

Disposal pits

Leaching to
groundwater

Overland f low

Contaminated
soil

Soil erosion

Surface water f low

Discharge to
surface waters

Wastewater

Wind

Potential receptor Ingestion Inhalation Dermal/emersion

Carnivorous birds
Aquatic organisms
Wetland plants
Terrestrial invertebrates
Small mammals

FIGURE 7.3
An example conceptual site model. ( Adapted from U.S. EPA. 2011. Environmental cleanup
best management practices: Effective use of the project life cycle conceptual site model.
EPA 542-F-11-011 July 2011.)