1. Does an analysis of polychlorinated biphenyl (PCB) distribution in mountain soils across China reveal a latitudinal fractionation paradox?
- Author
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Zheng, Qian, Nizzetto, Luca, Mulder, Marie D., Sáňka, Ondřej, Lammel, Gerhard, Li, Jun, Bing, Haijian, Liu, Xin, Jiang, Yishan, Luo, Chunlin, and Zhang, Gan
- Subjects
SOIL pollution research ,POLYCHLORINATED biphenyls analysis ,PARTITION coefficient (Chemistry) ,MOUNTAIN soils ,THERMODYNAMIC equilibrium - Abstract
Organic and mineral soil horizons from forests in 30 mountains across China were analysed for polychlorinated biphenyl (PCB). Soil total organic carbon (TOC) content was a key determinant of PCB distribution explaining over 90% of the differences between organic and mineral soils, and between 30% and 60% of the variance along altitudinal and regional transects. The residual variance (after normalization by TOC) was small. Tri- to tetra-CB levels were higher in the South in relation to high source density and precipitation. Heavier congeners were instead more abundant at mid/high-latitudes where the advection pattern was mainly from long range transport. This resulted in a latitudinal fractionation opposite to theoretical expectations. The study showed that exposure to sources with different characteristics, and possibly accumulation/degradation trends of different congeners in soils being out-of-phase at different latitudes, can lead to an unsteady large scale distribution scenario conflicting with the thermodynamic equilibrium perception. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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