Publication Summary

This report presents an assessment of the effectiveness of dioxin-related TMDLs in Western Washington. Washington State Department of Ecology (Ecology) is required to develop and implement Total Maximum Daily Loads (TMDLs) for impaired waters, and evaluate the effectiveness of the cleanup plan.

Evaluation of available discharge monitoring report (DMR) data and dioxin tissue bioaccumulation results indicates that both effluent and sludge NPDES permit target limits for dioxin are generally being met. Consequently, these facilities operations appear to comply with the state′s narrative water quality standard for toxic substances; thereby verifying the effectiveness of these four TMDLs.

(The pdf for this report was reposted on 2-18-03. The previous version had a units of measurement error.)

Washington State Department of Ecology (Ecology) is required to develop and implement Total Maximum Daily Loads (TMDLs) for impaired waters, and evaluate the effectiveness of the cleanup plan to achieve the needed improvement in water quality. Ecology developed dioxin TMDLs for four mills in Washington State that produce bleached pulp and/or paper products: Weyerhaeuser, Everett; Rayonier, Port Angeles; Simpson, Tacoma; and Weyerhaeuser, Cosmopolis.

The TMDLs were based on the narrative state water quality criterion of 0.014 parts per quadrillion (ppq) at the edge of the mixing or dilution zone. Maximum dioxin target limits of 10 ppq and 5 ppt were set for effluent discharge and sludge, respectively, in the NPDES permits to provide protection for human and aquatic organisms as recommended by EPA.

Weyerhaeuser, Everett ceased operation before any discharge monitoring results could be obtained from the facility. Evaluation of available data from the other facilities indicates compliance to the NPDES permit maximum effluent and sludge target limits set for dioxin. Moreover, fish and crab dioxin tissue bioaccumulation results, part of the permit requirements, show the facilities did not appear to pose a problem to public health at the time of data collection.