title: Critical evaluation of a new passive exchange-meter for assessing multimedia fate of persistent organic pollutants at the air-soil interface.
abstract: A new passive exchange meter (PEM) to measure inter-compartment fluxes of persistent organic pollutants (POPs) at the interface between soil and the atmosphere is described. The PEM uses labeled reference compounds (RC) added in-situ to vegetation litter deployed in open cylinders designed to trap the vertical downward export of the RCs while allowing free exchange of POPs between litter and air. Fluxes of native compounds (bulk deposition, volatilization and downward export) are quantitatively tracked. One scope of the PEM is to investigate the influence of biogeochemical controls on contaminant re-mobilization. The PEM performance was tested in a subtropical forest by comparing measurements under dense canopy and in a canopy gap; conditions in which deposition and turn-over of organic matter (OM) occur at different rates. Significant differences in fate processes were successfully detected. Surprisingly, mobilization by leaching of more hydrophobic compounds was higher under canopy, possibly as a result of canopy mediated enhancement of OM degradation.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academic of Sciences, Guangzhou 510640, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Ming
authors.forename: Luca
authors.initials: L
authors.lastname: Nizzetto
authors.forename: Katrine
authors.initials: K
authors.lastname: Borgå
authors.forename: Thorjørn
authors.initials: T
authors.lastname: Larssen
authors.forename: Qian
authors.initials: Q
authors.lastname: Zheng
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Gan
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D019212:Multimedia; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014197:Trees / Q000502:physiology; D014835:Volatilization
chemical_list: D000393:Air Pollutants; D012987:Soil; D012989:Soil Pollutants
keywords: Air; Fate; Flux; POPs; Semivolatile organic compounds; Soil