Polychlorinated Dibenzo-p-dioxins and Dibenzofurans Associated with Wood-Preserving Chemical Sites: Biomonitoring with Pine Needles

Gas chromatography-mass spectrometry (GC-MS) analysis of pine needle extracts from two pentachlorophenol wood-preserving sites detected relatively high overall concentrations of polychlorinated dibenzo-p-dioxins (PCDDs; 1798 and 935 ppt) and dibenzofurans (PCDFs; 310 and 141 ppt). The dominant congener was oetachlorodibenzo-p-dioxin (Cl₈DD), the ∑PCDDs > ∑PCDFs, and relatively low levels of the tetra-and pentachlorodibenzofurans (∑Cl₄DFs and Cl₅DFs) were detected. This pattern was similar to that observed for the PCDD and PCDF contaminants detected in commercial pentachlorophenol and significantly different from the pattern observed for combustion-derived PCDDs and PCDFs. The levels of these compounds were significantly lower in two “pristine” areas in the Kootenai National Forest and the Glacier-Waterton International Peace Park (i.e., ∑PCDDs was <10.8 and 9.22 ppt; ∑PCDFs was <2.65 and <1.31 ppt). There was a rapid decrease in the total PCDD and PCDF levels in pine needles with increasing distance from one of the pentachlorophenol wood-preserving sites. These data suggest that pine needles can be used as a biomonitor for emissions of PCDDs and PCDFs from wood-preserving chemical sites.