Environmental contamination by polychlorinated dibenzo-p-dioxins and dibenzofurans associated with pulp and paper mill discharge.

Sludge from seven pulp and paper mills was analysed for 2,3,7,8-TCDD. The level of contamination ranged from not detectable (1 pg/g) to over 400 pg/g. Analyses for other planar polychlorinated contaminants indicated high levels of contamination by other PCDDs and PCDFs. Polychlorinated xanthenes and xanthones were identified as potential interferences in these analyses.