Polyethylene samplers (PEs) were deployed at 11 locations in Alexandria, Egypt during summer and winter to test and characterize them as passive samplers for concentrations, sources, and seasonal variations of atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs). PE-air equilibrium was attained faster for a wider range of PAHs during the winter season possibly due to increased wind speeds. Calculated PE-air partitioning constants, K(PE-A), in our study [Log K(PE-A) = 0.9426 × Log K(OA) - 0.022 (n = 12, R(2) = 0.99, Std error = 0.053)] agreed with literature values within <46%. For parent (except naphthalene), mono- and dialkylated PAHs, active sampling based concentrations of PAHs were within an average factor of 1.4 (1.0-5.6) compared to the PE based values. For C(3-4) alkylated PAHs, K(PE-A) values were lower than predicted, on average by ~0.8 log units per carbon in the alkylation. Enthalpies of vaporization (ΔH(vap)) accurately corrected K(PE-A)s for temperature differences between winter and summer sampling. PAH profiles were dominated by naphthalene, phenanthrene, and alkylated phenanthrenes. Calculated diagnostic ratios indicated that PAHs originated mainly from vehicle emissions.

Polyethylene passive samplers (PEs) were used to measure concentrations of gaseous and dissolved polycyclic aromatic hydrocarbons (PAHs) in the air and water throughout the lower Great Lakes during summer and fall of 2011. Atmospheric Σ 15PAH concentrations ranged from 2.1 ng/m 3 in Cape Vincent (NY) to 76.4 ng/m 3 in downtown Cleveland (OH). Aqueous Σ 18PAH concentrations ranged from 2.4 ng/L at an offshore Lake Erie site to 30.4 ng/L in Sheffield Lake (OH). Gaseous PAH concentrations correlated strongly with population within 3-40 km of the sampling site depending on the compound considered, suggesting that urban centers are a primary source of gaseous PAHs (except retene) in the lower Great Lakes region. The significance of distant population (within 20 km) versus local population (within 3 km) increased with sub-cooled liquid vapor pressure. Most dissolved aqueous PAHs did not correlate significantly with population, nor were they consistently related to river discharge, wastewater effluents, or precipitation. Air-water exchange calculations implied that diffusive exchange was a source of phenanthrene to surface waters, while acenaphthylene volatilized out of the lakes. Comparison of air-water fluxes with temperature suggested that the significance of urban centers as sources of dissolved PAHs via diffusive exchange may decrease in warmer months. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants that originate from oil spills as well as anthropogenic and natural combustion processes. Major sources include fossil fuel combustion, metal production, waste incineration, residential and commercial biomass burning, and vehicular emissions. 1-5 PAHs are often associated with densely populated areas, especially in industrialized countries. 3,4,6,7 PAHs and their transformation products are a primary 34 carcinogenic component of urban air pollution and health effects resulting from chronic exposure 35 are a serious concern. 8,9 36 Polyethylene passive samplers (PEs) are cost-effective, simple tools with lower detection 37 limits than traditional active sampling techniques. Instead of pumping air or water through a 38 filter, PEs accumulate hydrophobic organic contaminants (HOCs) over time via diffusion, 39 accumulating only truly dissolved or gas-phase molecules. 10 Concentrations of truly dissolved 40 HOCs are of interest because this fraction is available for direct diffusive exchange between 41 water and other reservoirs such as air, biota, or sediment. 42 The use of PEs facilitates simultaneous spatially resolved measurements and calculations of air-water diffusive exchange rates. For most HOCs, concentrations measured by PEs reflect a time-integrated concentration representative of the entire deployment period. For compounds that equilibrate during deployment, concentrations reflect the most recent concentration the sampler was exposed to. PEs have previously been used to measure HOCs in water and air 11-13 and to calculate air-water gradients of HOCs, but this method has not been applied to the l...

23Polyethylene passive sampling was applied to quantify gaseous and 24 freely--dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes