Measurement of atmospheric deposition of polychlorinated biphenyls and their dry deposition velocities in an urban/industrial site in Turkey

Accumulations and temporal trends of polychlorinated biphenyls (PCBs) in olive tree components

In this study, ambient air samples, olive tree branches (1- and 2-year-old) and their leaves (particulate and dissolved phase) were collected simultaneously between January and December months at a suburban site of Bursa-Turkey. Total polychlorinated biphenyl (PCB) concentrations, sampled by employing passive air samplers, ranged from 0.03 to 0.08 ng/m³ in the atmosphere. The average annual total PCB concentrations belonging to the tree components were 1.14 ± 0.32 ng/g DM in dissolved phase in leaves, 0.71 ± 0.32 ng/g DM in particle phase on leaves, 1.06 ± 0.25 ng/g DM in 1-year-old branches, and 0.93 ± 0.23 ng/g DM in 2-year-old branches. It was determined that the correlation between PCB concentrations in olive tree components and the air was low. This result indicated that besides the tree-air exchange, other possible factors (such as soil-to-tree transitions, wind effect, etc.) affect the levels of PCB concentrations in the tree components. Total PCB concentrations decreased from summer to winter in all samples. The percentage ratio of PCB in the dissolved phase in the leaves was generally higher than other tree components in seasons. PCB homologous distributions indicated 5-CBs were dominant in the tree components and 3-CBs were dominant in the air samples. Highly chlorinated PCB congeners (8-CBs and 9-CBs) were found at low concentrations in both air and tree components samples. The samples indicated that the ratio of PCBs in tree components to the total (tree component+ambient air) PCBs slightly increased with increasing the chlorine number.

Effects of sampling interval on the passive air sampling of atmospheric PCBs levels

In this study, we collected Polychlorinated biphenyls (PCBs) using passive air samplers (PASs), between February 4, 2013 and February 2, 2014, with the sampling periods ranging from 10 to 60 days. The samples were collected with PASs that contained polyurethane foam (PUF). With these samples, 87 PCB congeners were analyzed. Sampling coefficient (R) values for the four seasons were calculated using both the high volume air sampler (HVAS) and PAS samples collected with the same time interval. The average of the annual concentrations of 87 PCB congeners, calculated using the R values specific to this study, was 234 ± 175 pg/m³. PCB congeners with 3- and 4- chlorines were dominant. The samples were collected at the same time interval but at different times to represent accumulation in the PASs. The linear regression coefficients (r) of the PCB mass accumulated in PASs against time ranged from 0.89 and 0.97 indicating that accumulation was linear. Moreover, the concentrations of the PCB congeners were statistically correlated with atmospheric conditions.

Atmospheric deposition of organochlorine pesticides by precipitation in a coastal area

Wet deposition fluxes of organochlorine pesticides (OCPs) were determined for rain samples collected in a coastal area of Turkey. Seventeen precipitation samples were collected over a 1-year period from 2008 to 2009. Rainwater was accumulated at the beginning of rain events using real time monitoring. Atmospheric concentrations were also measured in parallel with deposition samples. Both atmospheric concentrations and deposition fluxes were determined as particle and gas phases. The particle phase and dissolved phase deposition fluxes were 794.26 ± 756.70 ngm^-2 day^-1 and 800.77 ± 672.63 ngm^-2 day^-1, respectively. The washout ratios for OCP compounds were calculated separately for the particle and dissolved phases using the atmospheric concentrations and rain concentrations. The minimum washout ratio for the particle phase was 2339.47 for Endrin aldehyde, whereas the maximum washout ratio was 497593.34 for Methoxychlor. The maximum washout ratio for the dissolved phase was 247523.89 for Endosulfan beta, whereas the minimum washout ratio was 10169.69 for p,p'-DDT. The dry deposition velocities ranged from 0.01 to 1.67 cms^-1. The partitioning of wet deposition between the particle and dissolved phases was 50 % in terms of total OCP deposition.

Atmospheric concentrations, gaseous-particulate distribution, and carcinogenic potential of polycyclic aromatic hydrocarbons in Assiut, Egypt

The concentrations of 15 priority PAHs were determined in the atmospheric gaseous and particulate phases from nine sites across Assiut City, Egypt. While naphthalene, acenaphthene, and fluorene were the most abundant in the gaseous phase with average concentrations of 377, 184, and 181 ng/m(3), benzo[b]fluoranthene, chrysene, and benzo[g,h,i]perylene showed the highest levels in the particulate phase with average concentrations of 76, 6, and 52 ng/m(3). The average total atmospheric concentration of target PAHs (1,590 ng/m(3)) indicates that Assiut is one of the highest PAH-contaminated areas in the world. Statistical analysis revealed a significant difference between the levels of PAHs in the atmosphere of urban and suburban sites (P = 0.029 and 0.043 for gaseous and particulate phases, respectively). Investigation of diagnostic PAH concentration ratios revealed vehicular combustion and traffic exhaust emissions as the major sources of PAHs with a higher contribution of gasoline rather than diesel vehicles in the sampled areas. Benzo[a]pyrene has the highest contribution (average = 32, 4% for gaseous and particulate phases) to the total carcinogenic activity (TCA) of atmospheric PAHs. While particulate phase PAHs have higher contribution to the TCA, gaseous phase PAHs present at higher concentrations in the atmosphere are more capable of undergoing atmospheric reactions to form more toxic derivatives.

Determination of the sampler type and rainfall effect on the deposition fluxes of the polychlorinated biphenyls

Atmospheric concentration and deposition samples were collected between June 2008 and June 2009 in an urban sampling site Yavuzselim, Turkey. Eighty-three polychlorinated biphenyl (PCB) congeners were targeted in the collected samples. It was found that 90% of the total PCB concentration was in the gas phase. Deposition samples were collected by a wet-dry deposition sampler (WDDS) and a bulk deposition sampler (BDS). Average total deposition fluxes measured with the BDS in dry periods was 5500 ± 2400 pg/(m²day); average dry deposition fluxes measured by the WDDS in the same period were 6400 ± 3300 pg/(m²day). The results indicated that the sampler type affected the measured flux values. Bulk deposition samples were also collected in rainy periods by using the BDS and the average flux value was 8700 ± 3100 pg/(m²day). The measured flux values were lower than the values reported for the urban and industrial areas. Dry deposition velocities for the WDDS and BDS samples were calculated 0.48 ± 0.35 cm/s and 0.13 ± 0.15 cm/s, respectively.

Seasonal atmospheric deposition variations of polychlorinated biphenyls (PCBs) and comparison of some deposition sampling techniques

INTRODUCTION

Ambient air and bulk deposition samples were collected between June 2008 and June 2009. Eighty-three polychlorinated biphenyl (PCB) congeners were targeted in the samples.

DISCUSSION

The average gas and particle PCB concentrations were found as 393 ± 278 and 70 ± 102 pg/m(3), respectively, and 85% of the atmospheric PCBs were in the gas phase. Bulk deposition samples were collected by using a sampler made of stainless steel. The average PCB bulk deposition flux value was determined as 6,020 ± 4,350 pg/m(2) day. The seasonal bulk deposition fluxes were not statistically different from each other, but the summer flux had higher values. Flux values differed depending on the precipitation levels. The average flux value in the rainy periods was 7,480 ± 4,080 pg/m(2) day while the average flux value in dry periods was 5,550 ± 4,420 pg/m(2) day. The obtained deposition values were lower than the reported values given for the urban and industrialized areas, yet close to the ones for the rural sites. The reported deposition values were also influenced by the type of the instruments used. The average dry deposition and total deposition velocity values calculated based on deposition and concentration values were found as 0.23 ± 0.21 and 0.13 ± 0.13 cm/s, respectively.

Atmospheric polychlorinated biphenyl (pcb) inputs to a coastal city near the Marmara Sea

Recent studies have shown that polychlorinated biphenyl (PCB) levels are high in coastal sites. Various types of deposition events, including dry deposition, air-water exchange and wet deposition, were analyzed as part of the study to illustrate the pollution level. The atmospheric levels and deposition mechanisms of 82 PCBs were investigated in Mudanya, a coastal city in Turkey. A total of 175 samples and 112 blanks were collected. Air-water exchange and particle phase dry deposition fluxes were 120 ± 90 ng/m(2)-d and 125 ± 160 ng/m(2)-d, respectively. The wet-dry deposition sampler (WDDS) consisted of two reservoirs, wet and dry. Collected with the WDDS, the dry deposition flux was 21 ± 20 ng/m(2)-d, and the wet deposition fluxes (during the rainy period) were 145 ± 130 ng/m(2)-d and 195 ± 270 ng/m(2)-d for the dissolved and particulate phases, respectively. Mass transfer coefficients (MTCs), dry deposition velocities and washout ratios were calculated and compared with the literature values.