Publication Summary

The Department of Ecology conducted an inspection of the Boise Cascade bleached kraft pulp and paper mill at Wallula, Washington, during April 1992. The mill's discharge to the Columbia River was in compliance with NPDES permit limits for five-day biochemical oxygen demand (BOD5), total suspended solids (TSS), pH, and the salmonid bioassay. A 2,3,7,8-TCDD (dioxin) concentration of 2.9 pg/L was measured in the final effluent; this is within the 10 pg/L limit that becomes effective in 1994.

The Department of Ecology conducted an inspection of the Boise Cascade bleached kraft pulp and paper mill at Wallula, Washington, during April 1992. The mill's discharge to the Columbia River was in compliance with NPDES permit limits for five-day biochemical oxygen demand (BOD5), total suspended solids (TSS), pH, and the salmonid bioassay. A 2,3,7,8-TCDD (dioxin) concentration of 2.9 pg/L was measured in the final effluent; this is within the 10 pg/L limit that becomes effective in 1994.

Chemical analyses and bioassays indicated the final effluent had a low potential to cause toxicity in the receiving water, although trace levels of bioaccumulative dioxins, furans, and phenolics were detected. Concentrations of fecal coliform bacteria (30% Klebsiella) in the effluent suggested possible violations of state Class A water quality standards downstream of the mill. A limited survey of the Columbia River sediments showed substantial toxicity in 10-day bioassays with the amphipod Hyallela azteca. The reason for toxicity was not evident from chemical analysis of the sediments, but the mill did not appear to be the source of the problem.

Recommendations include: 1) initiating effluent monitoring for fecal coliform/Klebsiella bacteria, 2) re-evaluating the need for analyzing certain toxics in the effluent, 3) assessing the accuracy of future total phenols data submitted by the mill, 4) managing ASB sludge to prevent dioxin/furan release to the environment, and 5) doing additional bioassays of river sediments.