Background - trdoer40013

Appendix G is a Glossary of Terms. Often, and contrary to USEPA directive to

be transparent, discussion of risk assessment is obfuscated with technical jargon and

"terms of art." This appendix attempts to provide definitions for such terms in

simple business English and emphasizes the initial use of the term in bold italics.

Background

The USACE navigation mission entails maintenance and improvement of 40,225

km of channels, supporting a vital component of the Nation's transportation

infrastructure system. These waterways serve 400 ports, including 130 of the

Nation's 150 largest cities

The USACE dredge and/or permit for dredging an annual average of 191 to 229

million cu m of sediment from this navigation system at an annual cost of $400 to

$600 million. Dredging is the single most costly item in the Corps' Civil Works

budget. Corps grants are also permitted to the private sector for dredging and

disposing of an additional 764,600 cu m of sediment.

These dredged sediments, especially in urbanized and industrial harbors, may

exhibit high concentrations of various contaminants from years of unregulated

discharge and runoff. Selecting appropriate management options for contaminated

sediment is a difficult task, exacerbated by the rapidly diminishing capacity of

existing management locations and by public resistance to construction of new

facilities in traditional locations. Management options are quickly disappearing, and

the seasonal periods available for dredging are increasingly constrained by

environmental windows and other restrictions for the protection of sensitive aquatic

resources and wildlife.

Today's dredging manager faces a complex situation requiring a cost-efficient

operation which simultaneously considers the risks associated with various types of

dredging equipment, timing of dredging and management operations, selection of an

appropriate management alternative, and determining the relative importance of

ecological impacts from the management operation.

Fiscal constraints add further difficulty to a district's maintenance

dredging/management program. The use of risk management can facilitate the

efficient use of limited funds through evaluation of critical factors (e.g., cost,

equipment, windows, contaminants, disposal options, shoaling and channel

navigability, etc.) as well as the consequence of not dredging. This document

develops a repeatable and defendable framework to assess the risks from exposure

to contaminants in aquatic systems associated with management options.

What is Risk Assessment?

Risk assessment is the process of evaluating the impact of a stressor (e.g., a

chemical or physical condition) upon the health of individual humans or the

environmental well-being of a population or community of animals and plants. The

former is called human health risk assessment, and the latter is called ecological risk

Chapter 1 Overview of Ecological and Human Health Risk