A study was undertaken of the PCDD and PCDF export vectors from a major facility that comprises a bleached kraft pulp mill, paper mills, and previously, a timber processing sawmill. The PCDD and PCDF levels in pulps, untreated effluent, the final effluent, sludges, and discharge to the receiving waters, were studied. The total toxic equivalents were calculated, and the individual PCDD and PCDF profiles showed that there were several contributing sources of dioxins. The various effluent streams that contribute to the final effluent were studied, including the bleached effluent, the other kraft mill effluents, and site effluents from other processing areas. Mass balances of PCDDs and PCDFs from the effluent treatment systems are presented. The paper outlines the use of full PCDD and PCDF profile measurements as a means of identifying the point sources of dioxin contamination from within the facility, and outlines the procedures that are being implemented to control the emission of dioxins in the final effluent.

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