Historical inputs of PCDDs, PCDFs, and PCBs to a British Columbia interior lake: The effect of environmental controls on pulp mill emissions

A sediment core collected from Kamloops Lake, British Columbia, was used to assess historical inputs of polychlorinated dioxin and furans (PCDD/Fs) from a pulp mill and the effects of recent environmental controls. Principal components analysis reveals that four groups of compounds can be found in the sediments: moderately chlorinated PCDD/Fs produced during the bleaching of pulp with chlorine (e.g., TCDF); PCDD/Fs that have been produced by condensation of polychlorinated phenoxyphenol contaminants during pulping (e.g., HxCDDs); highly chlorinated PCDD/Fs that are derived from mixed sources (e.g., OCDD); and a series of PCBs that are probably derived from mixed sources. Strong correlations of CB13, CB15, and CB37 with the moderately chlorinated PCDD/Fs suggest that these PCBs have been produced in-situ by the pulp mill. In particular, CB15 is found in quantities rivaling those of total TCDF. In the 1930s-1950s, sediments exhibit minor contamination by the PCBs and higher chlorinated dioxins and furans. With the construction of the mill in 1965, large quantities of HxCDD and the tetra-chlorinated PCDD/Fs were released. Technological changes at the pulp mill have effected a drastic reduction in pulp mill PCDD/Fs in the 1990s.