title: Organochlorine pesticides in the atmosphere and surface water from the equatorial Indian Ocean: enantiomeric signatures, sources, and fate.
abstract: Nineteen pairs of gaseous and surface seawater samples were collected along the cruise from Malaysia to the south of Bay of Bengal passing by Sri Lanka between April 12 and May 4, 2011 on the Chinese research vessel Shiyan I to investigate the latest OCP pollution status over the equatorial Indian Ocean. Significant decrease of α-HCH and γ-HCH was found in the air and dissolved water phase owing to global restriction for decades. Substantially high levels of p,p'-DDT, o,p'-DDT, trans-chlordane (TC), and cis-chlordane (CC) were observed in the water samples collected near Sri Lanka, indicating fresh continental riverine input of these compounds. Fugacity fractions suggest equilibrium of α-HCH at most sampling sites, while net volatilization for DDT isomers, TC and CC in most cases. Enantiomer fractions (EFs) of α-HCH and o,p'-DDT in the air and water samples were determined to trace the source of these compounds in the air. Racemic or close to racemic composition was found for atmospheric α-HCH and o,p'-DDT, while significant depletion of (+) enantiomer was found in the water phase, especially for o,p'-DDT (EFs = 0.310 ± 0.178). 24% of α-HCH in the lower air over the open sea of the equatorial Indian Ocean is estimated to be volatilized from local seawater, indicating that long-range transport is the main source.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou, Guangdong 510640, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Huang
authors.forename: Yue
authors.initials: Y
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Weihai
authors.initials: W
authors.lastname: Xu
authors.forename: Gan
authors.initials: G
authors.lastname: Zhang
authors.forename: Zhineng
authors.initials: Z
authors.lastname: Cheng
authors.forename: Junwen
authors.initials: J
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Chongguo
authors.initials: C
authors.lastname: Tian
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D019156:Indian Ocean; D010575:Pesticides / Q000032:analysis*; D012623:Seawater / Q000032:analysis; D013188:Sri Lanka; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D014874:Water Pollutants, Chemical