Altitude dependence of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in surface soil from Tibetan Plateau, China.
Remote mountain areas besides high latitude regions are beginning to receive increased attention in studying the transport and behavior of persistent organic pollutants (POPs). In the present work, surface soil samples were collected from the Tibetan Plateau, the highest plateau in the world which includes the northern slope of Mt. Qomolangma, to investigate the levels and trends of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) along the altitudinal gradient. The average PCB and PBDE concentrations were 185.6 ng kg(-1)dry weight (dw) (range 47.1-422.6 ng kg(-1)dw) and 11.1 ng kg(-1)dw (range 4.3-34.9 ng kg(-1)dw), respectively. Regression analysis between the log-transformed TOC-normalized concentrations and the altitudes of the sampling sites showed two opposite trends with regard to altitude dependence: negative relationship with altitude below about 4500 m followed by a positive altitude dependence above this point. Considering minimum anthropogenic activities and very sparse precipitation in the north of Himalayas, the trends above 4500 m imply that the significant altitude dependence of these two groups of POPs were irrespective of pollution sources, but could be predicted by the global distillation effect involving cold condensation in high altitude mountain areas. Increasing levels of heavier congeners were found in higher altitude sites, although the lighter congeners were the main contributors to the total amount, suggesting that less volatile congeners seem to become enriched easier than those more volatile at higher altitudes in this region.
Wang
Pu
P
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Zhang
Qinghua
Q
Wang
Yawei
Y
Wang
Thanh
T
Li
Xiaomin
X
Li
Yingming
Y
Ding
Lei
L
Jiang
Guibin
G
D000531:Altitude; D002244:Carbon / Q000032:analysis; D002681:China; D004784:Environmental Monitoring; D005843:Geography; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D007700:Kinetics; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D011891:Rain; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D013696:Temperature; D018609:Tibet
D055768:Halogenated Diphenyl Ethers; D012987:Soil; D012989:Soil Pollutants; D002244:Carbon; D011078:Polychlorinated Biphenyls