Development of probability distribution functions for a PCP salmonid toxicity reference value
- Golder Associates Ltd., Burnaby, British Columbia (Canada)
- Triton Environmental Consultants Ltd., Richmond, British Columbia (Canada)
- Bell Pole Co. Ltd., Lumby, British Columbia (Canada)
Ecological risk assessment involving the hazard quotient (HQ) approach requires a toxicity reference value (TRV), or benchmark safe concentration, from which HQ is derived. For aquatic organisms, the TRV is conventionally expressed as an aqueous concentration, but may also be expressed as a critical body residue (CBR). In either case, to avoid excessive conservatism often inherent in generic multi-species-based regulatory criteria, and to maximize site specificity of a risk assessment, it is desirable to employ a TRV reflective of both the site and species of interest. Additionally, it is desirable to quantitatively express the uncertainty associated with the TRV by constructing a probability distribution function (PDF). As part of an on-going ecological risk assessment which includes development of risk-based soil remediation goals for PCP at a former wood pole treatment site in British Columbia, TRV-PDFs for salmonids were developed. Consideration was given to multiple effects endpoints (growth, reproduction and long-term survival), magnitude of the effect level (ECx data), shape of the PDF and potential for extrapolation from the individual to the population level. A re-evaluation of literature effects data was undertaken to ascertain ECx values for the various effects endpoints. Insufficient data specific to salmonids was available in the literature to develop a TRV-PDF directly from a frequency distribution of ECx data. However, additional insight afforded by data on fathead minnows and professional judgment resulted in a TRV-PDF which could be employed in the context of this risk assessment. The authors report here on the process, resultant PDFs and implications to risk-based soil remediation goals in comparison to use of generic multi-species based regulatory criteria.
- OSTI ID:
- 212088
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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