|
Ecological Risk Assessment (ERA) is the
evaluation of risk posed to the environment and non-human inhabitants by a
given condition. Ecological Risk is used to quantify the likelihood and
severity of adverse environmental effects for the purposes of establishing site
clean-up criteria, developing risk management plans, evaluating historic,
current or potential future environmental impacts, or seeking regulatory
approvals.
There is a fundamental difference between a Human Health
Risk Assessment and an Ecological Risk Assessment. While a Human Health Risk
Assessment is concerned with estimating the effects on individuals, an
Ecological Risk Assessment is generally concerned with estimating effects on
populations, communities and ecosystems. In some cases involving endangered
species, risks to individuals may be considered.
An Ecological Risk
Assessment is commonly required as part of a site specific risk assessment.
There are generally three levels of investigation that can be
conducted:
- Screening level assessment: essentially a
qualitative assessment of potential risks to important ecological
receptors;
- Preliminary quantitative risk assessment:
focuses on filling gaps identified at the screening level; and,
- Detailed quantitative risk assessment:
includes more detailed data and modelling.
Each level of the assessment follows the
conventional risk assessment paradigm which includes: problem formulation
(including receptor characterization); exposure assessment; hazard assessment;
and, risk characterization. These steps are integrated into each of the three
levels discussed above. Thus, each level in this tiered approach has the same
structure and builds upon the data, information, knowledge and decisions
generated from the preceding level. The level of the assessment is dependent on
the particular site being evaluated. All three levels may be performed at one
site, with the subsequent levels of assessment becoming more specific to
identified species and/or conditions, targeting efforts to areas of greatest
concern or uncertainty.
|
