Who Can Conduct a Risk Assessment?

ecological risk assessment can address risk to several receptors chosen to represent

the ecosystem associated with the dredged material disposal site.

These two types of risk assessment address the fate and transport of

contaminants in similar, if not identical manners. Those physical and chemical

processes which drive the distribution of contaminants will not change between the

two types of risk assessment. The two are linked in that the estimates of

contaminant uptake by biota (evaluated in the ecological risk assessment) may result

in exposure to humans if people eat that organism. Clearly, the feeding habits of a

commercial species, an ecological characteristic, will to a large extent determine

whether that species can pass a contaminant on to a human. This is the point where

ecological and human health risks are most closely linked. They diverge in the

discussion of toxicological processes and how these processes relate to potential

effects.

Who Can Conduct a Risk Assessment?

The selection of personnel to conduct a risk assessment depends on the level of

complexity addressed in the risk assessment. For example, a rough estimate of

exposure based on a simple sediment-water partitioning equation may be sufficient

to demonstrate little probability of bioavailability of a chemical and, hence, risk. In

such a case, operations personnel with expertise in engineering, chemistry, or marine

geology may be the only necessary personnel. In the most complex assessments (and

these are likely to be the least frequently encountered), an interdisciplinary team of

engineers, biologists, chemists, and physical scientists may be necessary.

Data Collection Requirements of Risk Assessment

The site selection process and the dredged material evaluation tiered approach

will satisfy most risk assessment data needs (Table 1). These data may have to be

reformulated to provide direct answers to the six questions posed earlier.

The initial question, "Are there 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

Hazard Identification question, "Are there stressors associated with a proposed

management action which may affect the survival or reproduction of these

receptors?" The Tier I characterization of the sediments relies on available results

Chapter 1 Overview of Ecological and Human Health Risk