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 gasexchange 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.

a b s t r a c tAmbient air and dry deposition samples were collected at suburban and urban sites in Izmir, Turkey. Atmospheric total (particle + gas) 14 PAHs concentrations were 36 ± 39 and 144 ± 163 ng m −3 for suburban and urban sites, respectively. Phenanthrene was the most abundant compound at all sites, and all samples were dominated by low molecular weight PAHs. Average particulate 14 PAH dry deposition fluxes were 8160 ± 5024 and 4286 ± 2782 ng m −2 day −1 and overall average particulate dry deposition velocities were 1.5 ± 2.4 and 1.0 ± 2.3 cm s −1 for suburban and urban sites, respectively. Soil samples were collected at suburban site. Average soil concentration for 14 PAH was 55.9 ± 14.4 ng g −1 dry weight. Calculated gas-phase air-soil exchange fluxes indicated that fluorene, phenanthrene, anthracene, and carbazole were deposited to soil in winter while they were volatilized in summer. Other compounds (fluoranthene-benzo[g,h,i]perylene) were deposited to soil in both periods. Annual average fluxes of PAHs representing soil to air (i.e., gas volatilization) and air to soil transfer (i.e., gas absorption, dry deposition, and wet deposition) processes were also compared. All processes were comparable for 14 PAHs however their input was dominated by gas absorption. Gas absorption dominated for lower molecular weight PAHs, however dry deposition dominated for higher molecular weight PAHs. The results have suggested that for fluorene, soil and air may be approaching a steady state condition. For the remaining compounds, there was a net accumulation into the soil.

Ambient air polycyclic aromatic hydrocarbon (PAH) samples were collected at a suburban (n ¼ 63) and at an urban site (n ¼ 14) in Izmir, Turkey. Average gas-phase total PAH ( P 14 PAH) concentrations were 23.5 ng m À3 for suburban and 109.7 ng m À3 for urban sites while average particle-phase total PAH concentrations were 12.3 and 34.5 ng m À3 for suburban and urban sites, respectively. Higher ambient PAH concentrations were measured in the gas-phase and P 14 PAH concentrations were dominated by lower molecular weight PAHs. Multiple linear regression analysis indicated that the meteorological parameters were effective on ambient PAH concentrations. Emission sources of particle-phase PAHs were investigated using a diagnostic plot of fluorene (FLN)/ (fluorine þ pyrene; PY) versus indeno[1,2,3-cd]PY/(indeno[1,2,3-cd]PY þ benzo[g,h,i]perylene) and several diagnostic ratios. These approaches have indicated that traffic emissions (petroleum combustion) were the dominant PAH sources at both sites for summer and winter seasons. Experimental gas-particle partition coefficients (K P ) were compared to the predictions of octanol-air (K OA ) and soot-air (K SA ) partition coefficient models. The correlations between experimental and modeled K P values were significant (r 2 ¼ 0.79 and 0.94 for suburban and urban sites, respectively, p < 0.01). Octanol-based absorptive partitioning model predicted lower partition coefficients especially for relatively volatile PAHs. However, overall there was a relatively good agreement between the measured K P and soot-based model predictions.

Semi-volatile organic compounds were monitored over a whole year, by collection of gas and particle phases every sixth day at a suburban site in Izmir, Turkey. Annual mean concentrations of 32 polychlorinated biphenyls (∑ 32 PCBs) and 14 polycyclic aromatic hydrocarbons (∑ 14 PAHs) were 348 pg/m 3 and 36 ng/m 3 , respectively, while it was 273 pg/m 3 for endosulfan, the dominant compound among 23 organochlorine pesticides (OCPs). Monte Carlo simulation was applied to the USEPA exposure-risk models for the estimation of the population exposure and carcinogenic risk probability distributions for heating and non-heating periods. The estimated population risks associated with dermal contact and inhalation routes to ∑ 32 PCBs, ∑ 14 PAHs, and some of the targeted OCPs (α-hexachlorocyclohexane (α-HCH), β-hexachlorocyclohexane (β-HCH), heptachlor, heptachlor epoxide, α-chlordane (α-CHL), γ-chlordane (γ-CHL), and p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT)) were in the ranges of 1.86 × 10 −16 -7.29 × 10 −9 and 1.38 × 10 −10 -4.07 × 10 −6 , respectively. The inhalation 95th percentile risks for ∑ 32 PCBs, ∑ 14 PAHs, and OCPs were about 6, 3, and 4-7 orders of magnitude higher than those of dermal route, respectively. The 95th percentile inhalation risk for ∑ 32 PCBs and OCPs in the non-heating period were 1.8-and 1.2-4.6 folds higher than in the heating period, respectively. In contrast, the 95th percentile risk levels for ∑ 14 PAHs in the heating period were 4.3 times greater than that of non-heating period for inhalation, respectively. While risk levels associated with exposure to PCBs and OCPs did not exceed the acceptable level of 1 × 10 −6 , it was exceeded for 47 % of the population associated with inhalation of PAHs with a maximum value of about 4 × 10 −6 .