title: [Contamination levels and source analysis of polycyclic aromatic hydrocarbons and organochlorine pesticides in soils and grasses from lake catchments in the Tibetan Plateau].
abstract: Soils and grasses samples were collected from 6 typical lake catchments in the central and northern Tibetan Plateau (TP) in August 2007 and analyzed for polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs, including HCHs and DDTs). The concentrations of sigma16 PAHs, sigma HCHs and sigma DDTs in soil samples were in the range of 60.6-614 ng x g(-1) (mean 194 ng x g(-1)), 0.06-0.74 ng x g(-1) (mean 0.31 ng x g(-1)) and N. D. -0.17 ng x g(-1) (mean 0.07 ng x g(-1)) while those of sigma15 PAHs (excluding NAP), sigma HCHs and sigma DDTs in grasses were in the range of 262-519 ng x g(-1) (mean 327 ng x g(-1)), 0.55-3.92 ng x g(-1) (mean 2.17 ng x g(-1)) and 0.20-2.19 ng x g(-1) (mean 0.92 ng x g(-1)), respectively. All compounds were significantly lower than those in European high mountains. The biological concentration effect of grasses to soils was notable with the values of BCF ranging from 4.2 to 19.3. No significant correlations were observed between the concentrations of POPs and the content of OM/lipid, or the altitude of the sampling sites. The PAHs profile was dominated by lighter constituents (2 & 3-ring PAHs accounted for higher than 80%). The special diagnostic ratios of PAHs suggested that PAHs in the TP were mainly produced by low-temperature combustion of biomass and fossil fuels, and the relatively low ratios of alpha/gamma-HCH and high ratios of o,p'-DDT/p,p'-DDT implied that the wide applications of lindane and dicofol contributed to the OCPs contamination in the TP. According to the backward airmass trajectory models, it was deduced that the westerly wind was the main source for both central and northern sites in the TP during winter. During summer, pollutants in the central sites of the TP were mainly from the Indian subcontinent while the northern sites were also affected by Chinese inland provinces.
authors.forename: Ting
authors.initials: T
authors.lastname: Xie
authors.forename: Shu-Juan
authors.initials: SJ
authors.lastname: Zhang
authors.forename: Rui-Qiang
authors.initials: RQ
authors.lastname: Yang
mesh_terms: D000531:Altitude; D003634:DDT / Q000032:analysis; D004784:Environmental Monitoring; D001556:Hexachlorocyclohexane / Q000032:analysis; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D060106:Lakes; D010573:Pesticide Residues / Q000032:analysis*; D006109:Poaceae / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis; D018609:Tibet
chemical_list: D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; C040534:alpha-hexachlorocyclohexane; D001556:Hexachlorocyclohexane; D003634:DDT; C016340:o,p'-DDT