title: Water-gas exchange of organochlorine pesticides at Lake Chaohu, a large Chinese lake.
abstract: Organochlorine pesticides (OCPs), a potential threat to ecosystems and human health, are still widely residual in the environment. The residual levels of OCPs in the water and gas phase were monitored in Lake Chaohu, a large Chinese lake, from March 2010 to February 2011. Nineteen types of OCPs were detected in the water with a total concentration of 7.27 ± 3.32 ng/l. Aldrin, DDTs and HCHs were the major OCPs in the water, accounting for 38.3%, 28.9% and 23.6% of the total, respectively. The highest mean concentration (12.32 ng/l) in the water was found in September, while the lowest (1.74 ng/l) was found in November. Twenty types of gaseous OCPs were detected in the atmosphere with a total concentration of 542.0 ± 636.5 pg/m(3). Endosulfan, DDTs and chlordane were the major gaseous OCPs in the atmosphere, accounting for 48.9%, 22.5% and 14.4% of the total, respectively. The mean concentration of gaseous OCPs was significantly higher in summer than in winter. o,p'-DDE was the main metabolite of DDT in both the water and gas phase. Of the HCHs, 52.3% existed as β-HCH in the water, while α-HCH (37.9%) and γ-HCH (30.9%) were dominant isomers in the gas phase. The average fluxes were -21.11, -3.30, -152.41, -35.50 and -1314.15 ng/(m(2) day) for α-HCH, γ-HCH, HCB, DDT and DDE, respectively. The water-gas exchanges of the five types of OCPs indicate that water was the main potential source of gaseous OCPs in the atmosphere. A sensitivity analysis indicated that the water-gas flux of α-HCH, γ-HCH and DDT is more vulnerable than that of HCB and DDE to the variation of the parameters. The possible source of the HCHs in the water was from the historical usage of lindane; however, that in the air was mainly from the recent usage of lindane. The technical DDT and dicofol might be the source of DDTs in the water and air.
authors.affiliation: MOE Laboratory for Earth Surface Process, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Ouyang
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Ning
authors.initials: N
authors.lastname: Qin
authors.forename: Xiang-Zhen
authors.initials: XZ
authors.lastname: Kong
authors.forename: Wen-Xiu
authors.initials: WX
authors.lastname: Liu
authors.forename: Qi-Shuang
authors.initials: QS
authors.lastname: He
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.forename: Yu-Jiao
authors.initials: YJ
authors.lastname: Jiang
authors.forename: Qing-Mei
authors.initials: QM
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Fu-Liu
authors.initials: FL
authors.lastname: Xu
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D000397:Air Pollution / Q000032:analysis; D002681:China; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D006843:Hydrocarbons, Chlorinated / Q000032:analysis* / Q000737:chemistry; D060106:Lakes / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis* / Q000737:chemistry; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D014877:Water Pollution, Chemical / Q000032:analysis
chemical_list: D000393:Air Pollutants; D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D014874:Water Pollutants, Chemical