Columbia River Dioxin Study

The Columbia River and segments of the Snake and Willamette Rivers are
currently water quality limited due to the presence of elevated levels
of 2,3,7,8-TCDD. As a result, U.S. EPA Region 10, established a Total
Maximum Daily Load (TMDL) of 6 mg of 2,3,7,8-TCDD/day based upon state
water quality standards applicable to the Columbia River basin and the
volume of water in the Columbia River. The data set focused on one or
two sampling locations in a specific segment of the river. Criteria
for choosing these locations were to: (1) sample at fishing sites, (2)
collect organisms that are consumed by Native Americans and others
fishing in the Columbia River basin, (3) collect organisms that are
good indicators of contaminant levels in the river and of levels of
contaminants that may be ingested by aquatic and terrestrial
predators. There were six locations which sampled dioxin/furans,
pesticides, polychlorinated biphenyls (PCBs), semi-volatiles,
polyaromatic hydrocarbons (PAHs), mercury (Hg) by using rod and reel,
electroshocking, setline and hoop and/or gill net.

The area of study is the Columbia River from Bonneville Dam to McNary Dam.

Samples consist of composite between 3-8 samples and individual
fillets. Crayfish will be handled in the same way as fish using
baited traps. Crayfish are represented as a composite of 30
organisms, following whole body analysis. Total dioxin and furan
concentrations were determined by the laboratory as the sum of the
individual congeners that were detected.

The metadata for this data was taken from the U.S. Environmental
Protection Agency's Columbia River Basin: Biota Database Abstracts.