title: Seasonal trend of ambient PCDD/Fs in Tianjin City, northern China using active sampling strategy.
abstract: The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were investigated within a seasonally active sampling scheme during Jun 2008 and Jan 2009 in Tianjin City, northern China. The PCDD/F concentrations ranged 14.2-172 fg I-TEQ/m3 (average 69.3 fg I-TEQ/m3) in summer and (89.8-1.01) x 10(3) fg I-TEQ/m3 (average 509 fg I-TEQ/m3) in winter, respectively, except for the E-waste dismantling site where much higher values were observed (1.04 x 10(3) fg I-TEQ/m3 in summer and 7.123 x 10(3) fg I-TEQ/m3 in winter). The results indicated a significantly seasonal trend with higher TEQ values in winter as compared with summer, which could be related to increased emission sources and seasonal variations of the atmospheric boundary layer height. 2,3,4,7,8-PeCDF was the dominant contributor to the total PCDD/F toxic equivalents, and 2,3,7,8-TCDD was detected at almost all the sampling sites in winter. Most of the similarly substituted PCDD/F congener pairs exhibited high correlations, suggesting that they might have similar environmental fate or sources. But different seasonal and spatial distributions of PCDD/F concentrations indicated that the emission sources might be intermittent.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. ding-lei-sdu@163.com
authors.forename: Lei
authors.initials: L
authors.lastname: Ding
authors.forename: Yingming
authors.initials: Y
authors.lastname: Li
authors.forename: Pu
authors.initials: P
authors.lastname: Wang
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Li
authors.forename: Zongshan
authors.initials: Z
authors.lastname: Zhao
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Tuan
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D001572:Benzofurans / Q000737:chemistry*; D002681:China; D002947:Cities; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D012621:Seasons
chemical_list: D000393:Air Pollutants; D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins