中文摘要：

2007年8月采集了青藏高原中部与北部6个典型湖泊流域的土壤与牧草样品,分析了样品中多环芳烃和有机氯农药（包括六六六和滴滴涕）的污染水平.土壤样品中Σ16PAHs、ΣHCHs和ΣDDTs的浓度范围分别为60.6-614 ng·g^-1（平均194 ng·g^-1）、0.06-0.74 ng·g^-1（平均0.31 ng·g^-1）和N.D.-0.17 ng·g^-1（平均0.07 ng·g^-1）.牧草样品中Σ15PAHs（不包括萘）、ΣHCHs和ΣDDTs的浓度分别为262-519 ng·g^-1（平均327 ng·g^-1）,0.55-3.92 ng·g^-1（平均2.17ng·g^-1）和0.20-2.19 ng·g^-1（平均0.92 ng·g^-1）,均远低于欧洲高山中相应介质中POPs的浓度.牧草的生物浓缩效应显著,其生物浓缩因子达到4.2-19.3.POPs的浓度分布与有机质/脂肪含量、海拔均无显著相关关系.PAHs的组成以较轻组分（2、3环PAHs）为主,占总浓度的80%以上.PAHs的特征单体比值表明生物质和化石燃料的低温燃烧是青藏高原PAHs的主要来源,同时较低的α/γ-HCH比率和较高的o,p＇-DDT/p,p＇-DDT比率表明,林丹以及三氯杀螨醇的使用对高原介质中有机氯农药的污染有一定的贡献.根据反向气团轨迹模型,推断冬季青藏高原中部与北部的污染主要受西风带影响,夏季高原中部位点的污染物主要源自印度次大陆,而北部位点还受到中国内陆省份的影响.

英文摘要：

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 Σ16PAHs,Σ HCHs and Σ DDTs in soil samples were in the range of 60. 6-614 ng·g^-1 mean 194ng·g^-1,0.06-0.74 ng·g^-1 mean 0.31 ng·g^-1 and N. D.-0.17 ng·g^-1 mean 0.07 ng·g^-1 while those of Σ15PAHs（ excluding NAP）,Σ HCHs andΣ DDTsin grasses were in the range of 262-519 ng·g^-1 mean 327 ng·g^-1,0.55-3.92 ng·g^-1 mean 2.17 ng·g^-1 and 0.20-2.19 ng·g^-1 mean 0.92 ng·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. 2to 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 α /γ-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.