Will the use of risk assessment require an expensive or time-consuming data collection program?

Technical Note DOER-R1

September 1998

of decision making. It merely enhances them. In the decision-making process, risk assessment

applies best in cases where

Site selection or dredged material evaluation has indicated potential environmental effects.

It appears that the integration of site selection data and dredged material characterization

around site-specific assumptions may improve the decision maker's understanding of the

potential for effects.

A formal assessment is not something to be applied to every project. It is most applicable to projects

that have

Reached Tier IV and concern about specific bioaccumulative compounds or toxic compounds

remains.

Potential to affect a local sensitive habitat or species.

Outstanding exposure issues where a risk assessment will allow realistic use of information

about the natural history of a species such as foraging areas, breeding times, and migration

patterns.

Potential human health exposure either directly to sediments or through the food chain.

Issues associated with environmental windows.

Risk assessment is not applied to the typical dredged material site or project that is easily handled

through the existing technical framework. Rather it applies in those cases where an extended

analysis allows the dredged material manager to address such real-world conditions as sediment

matrix effects, bioavailability, intermittent use of the site by a species of concern, the mitigating

effects of a specific management technology, the likely exposure to people fishing recreationally,

etc.

Will the use of risk assessment require an expensive or time-consuming data

collection program? The site selection process and the dredged material evaluation tiered

approach will satisfy most risk assessment data needs (Table 2). These data may have to be

reformulated to provide direct answers to the six questions posed earlier. Note that, as shown in

Table 2, the current tiered approaches do not explicitly address uncertainty.

The initial question, "Are humans, organisms, or habitats near the proposed dredged material

management activities?", is usually directly answered in the baseline studies of the site selection

process. These studies generally define and describe sensitive habitats or species, commercially

important species using the site, recreational or commercial uses of the site, and the types of

biological communities nearby. Risk assessment may require some reformulation or expansion of

this information if an analysis of potential exposure pathways reveals data gaps. For example, a

risk assessment may require a more detailed description of human use of the site or an expansion

of species descriptions to include information on life history. Usually such can be satisfied by an

expanded literature review.

The dredged material evaluation will provide the necessary data to address the question of Hazard

Identification, "Are stressors associated with a proposed management action that may affect the