3.3 Compilation of Information

These examples are not intended as an exhaustive list and serve merely as

illustrations to stimulate thinking about whether specific pathways warrant

evaluation.

The identification of relevant pathways is crucial to the evaluation process.

Only those pathways that have a potential to result in transport of contaminants

out of the site require consideration. Three components must be present before

any effects from COC are anticipated:

1. There must be a stressor. In the context of the UTM, a stressor would be

a COC associated with the dredged material within a CDF.

2. There must be a receptor. In the context of the UTM, a receptor could be

a person, wildlife, standard, or other receptor that could be adversely

affected by the stressor.

3. There must be a complete exposure route by which a stressor (COC) can

come into actual physiological contact with a receptor (ROC).

In order to determine the need to evaluate a pathway, it is important to clearly

identify all three elements: the stressor(s), the receptor(s), and the exposure

route(s) that connect them. The absence of a complete exposure route is one basis

for early elimination of a pathway(s) and stressor/receptor set(s) from further

consideration, so that the process can focus on situations that might reasonably

constitute a potential risk. This is the opportunity to focus questions upon issues

of real concern. Because the scoping process is so fundamental to the conduct

and acceptance of the UTM evaluation, it is important that Federal and State

agencies, stakeholders, and the general public have meaningful participation in the

scoping process.

The rationale for carrying, or not carrying, each pathway into the tiered

evaluation should be documented, and a list of pathways to be evaluated should

be developed at this point.

3.3 Compilation of Information

A separate Tier I evaluation should be conducted for each relevant pathway to

be evaluated, because each pathway has specific characteristics. However, the

Tier I evaluation process is very similar for every pathway. The generic Tier I

evaluation process is described here and referenced as the basic process for

conducting the Tier I evaluation in the detailed chapters on each of the pathways.

Much of the existing information used in Tier I evaluations of one pathway will

also be useful in evaluation of other relevant pathways. Therefore, whichever

pathway is evaluated first will require the greatest Tier I effort, and Tier I

evaluations of subsequent pathways will build upon and use much of the same

information, requiring less effort.

Even if it is clear from the outset that the evaluation of a particular pathway

must be carried to higher tiers, Tier I should be conducted for each pathway. This

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Chapter 3

Initial Evaluations