Identification of dioxin and dioxin-like polychlorbiphenyls in plant tissues and contaminated soils

The environmental analysis laboratory (EAL) of the Taiwan environmental protection administration (TEPA) has been monitoring certain sites polluted in southern Taiwan by pentachlorophenol manufacture. The analytical results revealed peculiarities in the concentration distributions in plant tissues. There are no available data on dioxin and dioxin-like polychlorbiphenyls (DL-PCBs), which can be taken up from contaminated soils by plant tissues. Thus, the aims of this study were to identify, understand, and to validate these dioxin and DL-PCBs concentrations in plant tissues of the contaminated soils. This research analyzed ten species of plant tissues, including tappa (Boussonetia papyrifera) and common jasmin orange (Murraya paniculata) from sites in southern Taiwan, with different levels of contamination. Dioxin concentrations in these plant tissues ranged from 12.7 to 2919 ng WHO-TEQ(DF)/kg dry weight (d.w.), with average of 463 ng WHO-TEQ(DF)/kg d.w. (n=16). The DL-PCBs concentrations ranged from 0.236 to 1.75 ng WHO-TEQp/kg d.w., with an average of 0.605 ng WHO-TEQp/kg d.w. (n=8). Tappa is one of the most common and fastest growing plants in Taiwan. It also shows the highest tolerance to environmental contaminants and accumulates dioxin and DL-PCBs. This is one of the best species to take up dioxins and DL-PCBs effectively. It can be recommended as a candidate for dioxin and DL-PCB phyto-remediation. These data are useful to evaluate bioaccumulation of dioxin and DL-PCBs, and to study the capability of phyto-remediation in contaminated soils.