Tree barks reveal health risk of inhalation of dioxin-like polychlorinated biphenyl in rural China

Although the use of polychlorinated biphenyls has been restricted worldwide for several decades, these pollutants are still occurring in the environment due to their persistency and their anthropogenic production. So far, there is limited knowledge on their long-distance transport, and on the associated health risk following air inhalation, notably in Chinese rural areas. Here we studied polychlorinated biphenyls in tree bark across China to estimate the atmospheric concentrations of dioxin-like polychlorinated biphenyls and to calculate toxic equivalents. We found that the 12 dioxin-like polychlorinated biphenyls accounted for up to 34.7% of the total concentration of polychlorinated biphenyls. 41% of the sites showed carcinogenic risks. Polychlorinated biphenyl-126 and polychlorinated biphenyl-169 appear as convenient indicators of toxicity and risk.