Chemical Engineering / Kimya Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/14

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Access type: Open accessSubject: search.filters.subject.Air-water exchange

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  • Article
    Citation - WoS: 68
    Citation - Scopus: 75
    Air-Water Exchange of Polychlorinated Biphenyls (pcbs) and Organochlorine Pesticides (ocps) at a Coastal Site in Izmir Bay, Turkey
    (Elsevier Ltd., 2008) Odabaşı, Mustafa; Çetin, Banu; Demircioğlu, Eylem; Sofuoğlu, Aysun
    The air-water exchange of polychlorinated biphenyl (PCB) and organochlorine pesticides (OCPs) were investigated using paired air-water samples (n = 16) collected in July and February-March, 2005 from Guzelyali Port in Izmir Bay, Turkey. Atmospheric PCBs and OCPs were mainly in gas-phase in both periods. However, their dissolved and particle-phase water concentrations were comparable. For PCBs, 3 and 4-Cl congeners were dominant while chlorpyrifos, endosulfans and HCHs were the most abundant OCPs for all samples. Especially in summer, calculated net gas-exchange PCB fluxes were mainly volatilization from the water ranging from - 0.2 (volatilization, PCB-101) to - 30.0 (volatilization, PCB-31) ng m- 2 day- 1. For OCPs, net flux ranged from - 0.03 (volatilization, cis-nonachlor) to 1568 (deposition, endosulfan I) ng m- 2 day- 1 and they have seasonal variations with generally deposition in winter and volatilization in summer. However, endosulfan I, II, endosulfan sulfate, α- and γ-HCH deposited in both periods. The calculated residence times of PCBs and OCPs in the water column indicated that the gas-exchange in the Bay is at least as or a more important mechanism than advection. Annual gaseous absorption and volatilization fluxes were calculated and were used along with the estimated dry deposition fluxes and wet deposition fluxes measured recently at a suburban site in Izmir to determine the relative contributions of different atmospheric mechanisms to the pollutant inventory of the Bay water column. Results suggested that the relative contributions of all studied mechanisms to the water column PCB and OCP inventories were significant.
  • Article
    Citation - WoS: 24
    Citation - Scopus: 25
    Mass Transfer Coefficients for Polycyclic Aromatic Hydrocarbons (pahs) To the Water Surface Sampler: Comparison To Modeled Results
    (Elsevier Ltd., 2001) Odabaşı, Mustafa; Sofuoğlu, Aysun; Holsen, Thomas M.
    A sampling program was conducted between June and October 1995 in Chicago, IL using a modified water surface sampler (WSS) and dry deposition plates to measure the particulate dry deposition and gas exchange of PAHs. Oxygen transfer experiments were also conducted to evaluate the collection properties of the WSS for gas-phase compounds. Gas-phase fluxes were determined by subtracting the dry deposition plate fluxes (particulate) from WSS fluxes (particulate+gas). These fluxes were divided by concurrently measured ambient concentrations to obtain overall gas phase mass transfer coefficients. Two different two-film models, one developed based on experiments performed with the WSS and, one previously published, were compared to these results. Experimentally determined average gas phase overall mass transfer coefficient (Kg) for seven PAHs was 0.74±0.52cms-1. Experimental Kg values agreed well with those predicted by the model developed for WSS. The values predicted by previously proposed models were within a factor of 3 of the experimental ones.