SPECIES SELECTION FOR AN ECOLOGICAL RISK ASSESSMENT OF THE COLUMBIA RIVER AT THE HANFORD SITE, WASHINGTON, USA

We describe a two-tier screening methodology used to select receptor s pecies for an ecological risk assessment of the Columbia River at the Hanford Site in south-central Washington state. This approach was deve loped and implemented under the guidance of the Columbia River Compreh ensive Impact Assessment Management Team (CRCIA Team), a public steeri ng committee comprised of members of regulatory agencies, native Ameri can tribes, and other stakeholders. Three hundred sixty-eight species that occur in the riverine and riparian communities of the Columbia Ri ver were reduced to 52 using criteria identified by an independent pan el of biologists (tier I) and by scoring and ranking species based on their potential exposure to contaminated media (tier II). This two-tie r screening methodology could be implemented at other locations where the number of species present must be reduced for an ecological risk a ssessment and where receptor species with relatively high potential co ntaminant exposures need to be evaluated. Participation of the CRCIA T eam in the species selection process facilitated agreement between ris k assessors, regulators, and stakeholders as to the number and kinds o f organisms to be evaluated in our risk assessment. It is critical tha t regulators and stakeholders be involved in the selection of receptor s to ensure that species of public interest as well as ecologically re levant species are evaluated in ecological risk assessments. This appr oach will increase the likelihood that such risk assessments will be u sed in management decisions.