PW16 Ecological Risk Assessment (General)
Exhibit Hall
8:00 AM - Wednesday
(PW262) Are standardized toxicity reference values needed for ecological risk assessment?
Mackintosh, C1, Mann, G1, Allard, P1, 1 Azimuth Consulting Group Inc., Vancouver, British Columbia, Canada
ABSTRACT- Toxicity Reference Values (TRVs) are used in Ecological Risk Assessment (ERA) to define levels of maximum acceptable exposure (or intake doses) when assessing potential risks to wildlife. While standardized exposure limits (e.g., reference doses) are generally widely used in human health risk assessments, this is not the case for ERA. Furthermore, available guidance for TRV derivation is not sufficiently detailed to ensure consistency between ERAs. While this does allow the risk assessor flexibility in selecting TRVs based on site-specific factors such as bioavailability, receptor organisms, and protection goals, it can also lead to significant inequities in environmental protection among sites. Some jurisdictions have addressed this by accepting TRVs published by Oak Ridge National Laboratory (ORNL) (Sample et al. 1996), the EPA (i.e., Ecological Soil Screening Levels, EPA 2003), or others. The objectives of this paper are to (1) place published TRV values (e.g., ORNL, and EPA) into context with NOAEL and LOAEL doses determined from a comprehensive literature review, and to (2) discuss the general advantages and disadvantages of adopting standardized TRVs or derivation methods. Ultimately the intent is to generate discussion on whether standardized TRVs would benefit ERA, or alternatively, whether a more detailed and consistent guidance needs to be developed.
Key words: ecological risk assessment, toxicity reference values