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The indoor and outdoor concentrations of 30 polycyclic aromatic hydrocarbons (PAHs) were measured in 55 nonsmoking residences in three urban areas during June 1999-May 2000. The data represent the subset of samples collected within the Relationship of Indoor, Outdoor, and Personal Air study (RIOPA). The study collected samples from homes in Los Angeles, CA, Houston, TX, and Elizabeth, NJ. In the outdoor samples, the total PAH concentrations (sigmaPAH) were 4.2-64 ng m(-3) in Los Angeles, 10-160 ng m(-3) in Houston, and 12-110 ng m(-3) in Elizabeth. In the indoor samples, the concentrations of sigmaPAH were 16-220 ng m(-3) in Los Angeles, 21-310 ng m(-3) in Houston, and 22-350 ng m(-3) in Elizabeth. The PAH profiles of low molecular weight PAHs (3-4 rings) in the outdoor samples from the three cities were not significantly different. In contrast, the profiles of 5-7-ring PAHs in thesethree citieswere significantlydifferent, which suggested different dominant PAH sources. The signatures of 5-7-ring PAHs in the indoor samples in each city were similar to the outdoor profiles, which suggested that indoor concentrations of 5-7-ring PAHs were dominated by outdoor sources. Indoor-to-outdoor ratios of the PAH concentrations showed that indoor sources had a significant effect on indoor concentrations of 3-ring PAHs and a smaller effect on 4-ring PAHs and that outdoor sources dominated the indoor concentrations of 5-7-ring PAHs.

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Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured at urban/industrial, suburban, coastal, and rural areas in New Jersey as part of the New Jersey Atmospheric Deposition Network. Concentrations of 36 PAH compounds were measured in the gas and particle phases in air and in precipitation at nine sites at regular intervals from October 1997 through May 2001. Gas-phase and particle-phase sigma36PAH concentrations ranged from 0.45 to 118 ng m(-3) and from 0.046 to 172 ng m(-3), respectively, and precipitation concentrations ranged from 11 to 16200 ng L(-1). PAH concentrations vary spatially across the region, with the highest concentrations occurring at the most heavily urban and industrial locations. Average gas absorption deposition ranged from 0.004 (naphthacene) to 5040 (methylphenanthrenes) ng m(-2) d(-1), and dry particle deposition PAH fluxes ranged from 0.11 (naphthacene) to 300 (benzo[b+k]fluoranthene) ng m(-2) d(-1) at the nine sites. Average atmospheric wet deposition PAH fluxes at the seven sites ranged from 0.40 (cyclopenta[cd]pyrene) to 140 (methylphenanthrenes) ng m(-2) d(-1). These represent the first comprehensive estimates of PAH deposition to New Jersey and the Mid-Atlantic East Coast.

The first estimates of atmospheric deposition fluxes of polychlorinated biphenyls (PCBs) to the Hudson River Estuary are presented. Concentrations of PCBs were measured in air, aerosol, and precipitation at nine sites representing a variety of land-use regimes at regular intervals from October 1997 through May 2001. Highest concentrations in the gas phase were observed at urban sites such as Camden and Jersey City (sigmaPCB concentrations averaged 3250 and 1260 pg m(-3), respectively). In great portions of the state encompassing forested, coastal, and suburban environments, gas-phase sigmaPCB concentrations were essentially the same (averaging 150-220 pg m(-3)). This spatial trend suggests that atmospheric PCBs arise from highly localized, urban sources which influence atmospheric concentrations and deposition fluxes over a distance of a few tens of kilometers. Atmospheric sigmaPCB deposition fluxes (gas absorption + dry particle deposition + wet deposition) ranged from 7.3 to 340 microg m(-2) yr(-1) and increased with proximity to urban areas. While the magnitude of the fluxes increased with urbanization,the relative proportions of wet, dry, and gaseous deposition remained largely constant. Because the Hudson River Estuary is adjacent to urban areas such as Jersey City, it is subject to higher depositional fluxes of PCBs. These depositional fluxes are at least 2-10 times those estimated for the Chesapeake Bay and Lake Michigan. Inputs of PCBs to the Hudson River Estuary from the upper Hudson River and from wastewater treatment plants are 8-18 times atmospheric inputs, and volatilization of PCBs from the estuary exceeds atmospheric deposition of low molecular weight PCBs.

The air-water exchange of polychlorinated biphenyls (PCBs) often results in net volatilization, which is thought to be the most important loss process for PCBs in many systems. Previous investigations of the air-water exchange of PCBs have been hampered by difficulties in treatment of the uncertainty in the calculation of air/water fugacity ratios. This work presents a new framework for the treatment of uncertainty, where uncertainty in physical constants is handled differently from random measurement uncertainty associated with random samples, and it further investigates the sorption of PCBs to colloids (dissolved organic carbon). Simultaneous measurements of PCBs in the air and water of five water quality management zones of the Delaware River were taken in 2002 in support of the total maximum daily load (TMDL) process. Gas-phase concentrations of IPCBs ranged from 110 to 1350 pg m(-3), while dissolved water concentrations were between 420 and 1650 pg L(-1). Shallow slopes of log Koc vs. log Kow plots indicated a colloidal contribution to the apparent dissolved-phase concentrations, such that a three-phase partitioning model was applied. Fugacity ratios for individual congeners were calculated under the most conservative assumptions, and their values (log-transformed) were examined via a single-sample T-test to determine whether they were significantly less than 1 at the 95% confidence level. This method demonstrated that air-water exchange resulted in net volatilization in all zones over all cruises for all but seven high molecular weight congeners. Calculated net fluxes ranged from +360 to +3000 ng m(-2) d(-1) for sigma PCBs. The colloidal correction decreased the volatilization flux of sigma PCBs by approximately 30%. The decachlorinated congener (PCB 209), exhibited unusually high concentrations in the suspended solids, especially in the southern portions of the river, indicating that there is a distinct source of PCB 209 in the Delaware River.

One-and two-electron reduction potentials (E 1 and E 2 values) were calculated from published thermodynamic data for 39 halogenated C 1 and C 2 compounds, including many commonly encountered groundwater contaminants. Because reductive dehalogenation is an important pathway for their destruction under anaerobic conditions, information concerning the relevant reduction potentials may be useful for assessing the thermodynamic feasibility of a particular reaction, as well as in developing linear free energy relationships (LFERs) or other quantitative structure-activity relationships (QSARs) that may enable prediction of rates of transformation. E 1 values were calculated assuming a stoichiometry corresponding to dissociative electron transfer, which produces a carbon-centered radical and a halide ion. E 2 values were calculated for both hydrogenolysis and reductive β-elimination reactions. Uncertainties in the thermodynamic data for the organohalides under consideration may introduce substantial uncertainty in the resulting E 1 values. Hence, relationships between calculated E 1 values and various surrogate parameters were also investigated. E 1 values were correlated with lowest unoccupied molecular orbital (LUMO) energies and carbon-halogen homolytic bond dissociation energies (BDE values), which were computed via density functional theory. Correlations were also attempted between E 1 values and vertical attachment energies (VAE values), the latter representing experimental measures of the ease of reduction of a molecule to a radical anion in the gas phase. These alternate descriptors may provide a means for estimating E 1 . Additional studies will need to be undertaken to establish which descriptor best correlates with reactivity in environmental reductive dehalogenation.

Polycyclic aromatic hydrocarbons (PAHs, n = 36) were measured in the gas and particle phases in the atmosphere and the dissolved and particle phases in the waters of the New York-New Jersey Harbor Estuary, USA, during a weeklong intensive field campaign in July 1998. Mean total (gas + particulate) phenanthrene and pyrene concentrations were 3.3 and 0.33 ng/m3, respectively, over Raritan Bay, and 14 and 1.1 ng/ml, respectively, over New York Harbor. Similar PAH profiles (p values < 0.01) in the atmospheric gas phase and the dissolved phase in water demonstrate the close coupling of the air and water compartments. Air-water exchange fluxes of PAHs estimated using shore-based air data lead to erroneous flux estimates when compared to those derived using over-water air samples. The gross absorptive air-water flux dominates atmospheric loadings (wet, dry particle, gas absorption) to the estuary for PAHs of molecular weight < 234 g/mol. Dry particle deposition is increasingly more important for the higher-molecular-weight, particle-bound PAH species. Gross volatilization dominates gross absorption for the majority of PAHs in the New York-New Jersey Harbor Estuary.