New classes of organic pollutants in the remote continental environment – Chlorinated and brominated polycyclic aromatic hydrocarbons on the Tibetan Plateau

Halogenated polycyclic aromatic hydrocarbons are carcinogenic and ubiquitous environmental organic pollutants. The abundance and sources of these compounds have not been studied in remote environments. We collected and analyzed air, soil, lichen, and moss samples from the Tibetan Plateau. Concentrations of chlorinated polycyclic aromatic hydrocarbons were 0.78–4.16 pg/m3 in air, 3.11–297 pg/g in soil, 260–741 pg/g in lichens, and 338–934 pg/g in mosses. Concentrations of brominated polycyclic aromatic hydrocarbons were 0.15–0.59 pg/m3 in air, 0.61–72.3 pg/g in soil, 33.5–64.9 pg/g in lichens, and 20.5–72.5 pg/g in mosses. The dominant congeners were 9- and 2-chlorophenanthrene, 1-chloropyrene, 3-chlorofluoranthene, and 1-bromopyrene. We found correlations between congener concentrations in lichens and in air, and lichens effectively predicted near-ground atmospheric concentrations of the pollutants. The…