Table 1. Advantages and Limitations of Risk Assessment

Technical Note DOER-R1

September 1998

Table 1

Advantages and Limitations of Risk Assessment

Advantages

Site and Technology Specific

Can address site- and technology-specific contingencies and variations without being overly

conservative (avoids the pitfalls of numerical standards)

Flexible

Can modify the organism's estimated exposure based on site-specific information

Iterative

Can apply "what if?" scenarios to evaluate the effects of various assumptions or changes in design

for a given disposal alternative

Inclusive

Accommodates the input of various interested parties, often referred to as stakeholders

Objective

Focuses upon several endpoints and presents an estimate of risk with reference to these endpoints

Avoids false positives

Avoids false positives associated with simple statistical comparisons between reference and test

sediments

Transparent

Makes the decision-making process more explicit

Value Added

Use the same risk assessment at a site with multiple projects over several years

Limitations

Results are site specific

Risk assessment results cannot be universally applied in the same manner as a criterion or advisory

level

Dependent on extrapolations

Fate and transport models, toxicity estimates, and exposure estimates will use extrapolations from

various data sets with varying degrees of uncertainty

Requires careful and complete communication of uncertainties

The uncertainty in a risk estimate must be explicitly described for each extrapolation or risk estimate

Even relatively complex risk assessments are easily iterated because the calculations of exposure

and risk are easily automated on computer spreadsheets. This allows the dredged material manager

to apply what-if scenarios to evaluate the effects of various assumptions or changes in a given

disposal alternative. This can be a significant advantage in choosing among alternative management

options or selecting sites. This property of risk assessment is also useful in attempting to decide

how the timing of disposal may affect an outcome by making different assumptions regarding

various seasons (i.e., helping to decide upon appropriate "environmental windows").

Risk assessment is inclusive because it can accommodate the input of various interested parties,

often referred to as stakeholders, in the risk management process. These stakeholders may be

regulators, state agencies, commercial interests, or environmental groups. Where appropriate or

necessary, the risk assessment considers their input in the development of exposure scenarios. The

exposure scenarios are the particular, site-specific, and detailed descriptions of how a human or an