TISSUE-DEPENDENT DISTRIBUTION AND BIOACCUMULATION OF POLYCHLORINATED DIBENZO-p-DIOXINS AND DIBENZOFURANS IN VEGETATION SAMPLES COLLECTED FROM DONGTING LAKE, CHINA

摘要

The concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soils and different species of vegetation collected from the Dongting Lake region, China. Use of sodium pentachlorophenate (Na-PCP) was the main contamination source of PCDD/Fs for soil/sediment and vegetation in the Dongting Lake region. Reed (Phragmitas communis Trin), Polygonum orientate L,, and Artemisia selengensis Turcz ex Bess were selected as model plants to explore the pathway of PCDD/Fs transfer from contaminated soil to vegetation. In the vegetation tissue samples, the total international toxic equivalency values ranged from 0.14 to 1.64 pg international toxic equivalency/g dry weight with a mean value of 0.67 pg international toxic equivalency/g dry weight. Polychlorinated dibenzo-p-dioxins and dibenzofurans congener distribution and bioaccumulation varied among vegetation species. Polychlorinated dibenzo-p-dioxins and dibenzofuran levels in the leaves were found to be higher than those in the root and stem, which were affected considerably by volatilization from contaminated soil. Volatilization from polluted soil and subsequent sorption to leaves may be a significant pathway for contamination of vegetation in Dongting Lake region.