Technical Bulletin No. 0568: A Study of the Variability of 2,3,7,8-TCDD and 2,3,7,8-TCDF in Bleached Kraft Mill Pulps, Sludges, and Treated Wastewaters

This report documents the variability of 2,3,7,8-TCDD and 2,3,7,8-TCDF in final bleached pulps, dewatered sludges, and treated effluents from three bleached kraft mills. The study focused on the uncertainty associated with sampling and compositing, analytical precision, and process variability. Results indicated that (1) analytical laboratory precision was more significant than sampling and compositing; (2) analytical precision, defined by the relative standard deviation, was 18% (TCDD) and 6% (TCDF) for bleached pulps, 18% (TCDD) and 14% (TCDF) for dewatered sludges, and 56% (TCDD) and 22% (TCDF) for treated effluents; (3) significant daily variability attributed to the process was noted for pulp samples but not for the sludges and effluents.