title: Soil concentrations, occurrence, sources and estimation of air-soil exchange of polychlorinated biphenyls in Indian cities.
abstract: Past studies have shown potentially increasing levels of polychlorinated biphenyls (PCBs) in the Indian environment. This is the first attempt to investigate the occurrence of PCBs in surface soil and estimate diffusive air-soil exchange, both on a regional scale as well as at local level within the metropolitan environment of India. From the north, New Delhi and Agra, east, Kolkata, west, Mumbai and Goa and Chennai and Bangalore in the southern India were selected for this study. 33 PCB congeners were quantified in surface soil and possible sources were derived using positive matrix factorization model. Net flux directions of PCBs were estimated in seven major metropolitan cities of India along urban-suburban-rural transects. Mean Σ33PCBs concentration in soil (12ng/g dry weight) was nearly twice the concentration found in global background soil, but in line with findings from Pakistan and urban sites of China. Higher abundance of the heavier congeners (6CB-8CB) was prevalent mostly in the urban centers. Cities like Chennai, Mumbai and Kolkata with evidence of ongoing PCB sources did not show significant correlation with soil organic carbon (SOC). This study provides evidence that soil is acting as sink for heavy weight PCB congeners and source for lighter congeners. Atmospheric transport is presumably a controlling factor for occurrence of PCBs in less polluted sites of India.
authors.affiliation: SRM Research Institute and Department of Civil Engineering, SRM University, Kattankulathur, Tamil Nadu, India. Electronic address: paromita.c@res.srmuniv.ac.in.
authors.forename: Paromita
authors.initials: P
authors.lastname: Chakraborty
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Gan
authors.initials: G
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: SRM Research Institute and Department of Civil Engineering, SRM University, Kattankulathur, Tamil Nadu, India.
authors.forename: Sakthivel
authors.initials: S
authors.lastname: Selvaraj
authors.affiliation: Norwegian Institute for Air Research, Box 100, NO-2027 Kjeller, Norway; Universityof Oslo, Department of Chemistry, Box 1033, NO-0315 Oslo, Norway.
authors.forename: Knut
authors.initials: K
authors.lastname: Breivik
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Jones
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring; D004787:Environmental Pollution / Q000706:statistics & numerical data; D007194:India; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D012987:Soil; D012989:Soil Pollutants; D011078:Polychlorinated Biphenyls
keywords: Fugacity fractions; Levels; PCB; PMF model; Sources