Henry's law constants for the polychlorinated biphenyls

Burkhard, Lawrence P.; Armstrong, David E.; Andrén, Anders

doi:10.1021/es00137a002

Cited by 124 publications

(135 citation statements)

References 29 publications

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“…The dimensional form of the Henry's law constant (H d ) HRT) may be estimated as the ratio of a compound's saturation vapor pressure and aqueous solubility (22). Both parameters are temperature dependent, with the result that the temperature dependence of H d is somewhat less than that of the saturation vapor pressure.…”

Section: Pcb Measurementsmentioning

confidence: 99%

Surface Exchange and Transport Processes Governing Atmospheric PCB Levels over Lake Superior

Honrath

Sweet

Plouff

1997

Environ. Sci. Technol.

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Measurements of gas phase PCB concentrations obtained at a site on the shore of Lake Superior are analyzed to determine the importance of regional air/surface exchange as a determinant of PCB concentration over the lake. During periods of onshore flow, results obtained in congenerspecific regression analyses of log concentration against reciprocal temperature are strongly dependent upon time of year. During months when the lake is colder than the overlying air (resulting in a stable atmosphere over the lake), regressions for onshore flow explain 48-63% of the observed variance in log C, and the regression slope and intercept are consistent with Henry's law equilibrium between the lower atmosphere over the lake and aqueous concentrations. Results consistent with Henry's law are obtained only when water temperature is assumed to be similar to air temperature measured at the site during flow off the lake; poor regression results (r 2 ) 0.00-0.06) are obtained when lake water temperature measured by data buoys is used. Based on consideration of the spatial variability of lake skin temperature during onshore flow periods, it is inferred that, under stable conditions, air/water equilibrium is reached rapidly and that atmospheric concentrations at the measurement site are primarily affected by air/water exchange within 10-30 km offshore. These results are consistent with consideration of potential limitations of regression analyses of log C versus reciprocal temperature. Furthermore, they indicate that the net exchange of PCBs during the stable season over large lakes (April-August or September for Lake Superior) may be significantly less than previously estimated. Regression analyses based on samples obtained during onshore flow in the unstable season and during over-land flow exhibit increased scatter and are inconsistent with the hypothesis of upwind equilibrium controlled by either Henry's law-or vapor pressure-mediated exchange at local temperatures. This result is consistent with rate limitations to atmosphere/ surface exchange over the lake and land surface and with the effect of atmospheric mixing processes. Implications of these results to the interpretation of concentration measurements at lakeside sites and the use of such measurements in calculations of the air/water exchange flux of PCBs over large lakes are discussed.

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Section: Pcb Measurementsmentioning

confidence: 99%

Surface Exchange and Transport Processes Governing Atmospheric PCB Levels over Lake Superior

Honrath

Sweet

Plouff

1997

Environ. Sci. Technol.

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“…An annual sea surface temperature range of 0-30ЊC was determined from data in Signell [32]. A temperature range is considered because Burkhard et al [33] show that flux rates can vary with variations in temperature. Flux is defined as a mass quantity per area and time.…”

Section: Gas/liquidmentioning

confidence: 99%

Fate and transport of pcbs at the new bedford harbor superfund site

Garton¹,

Bonner²,

Ernest³

et al. 1996

Enviro Toxic and Chemistry

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Abstract-A unique, holistic modeling approach, combining theoretical, empirical, and deterministic elements, was developed to define the ambient background transport of polychlorinated biphenyl (PCB) from New Bedford Harbor, to provide a baseline for remediation assessment of this Superfund site. Both empirical and deterministic elements characterized sediment processes. The deterministic section employed experimental data to describe flocculation through fluid shear, differential settling, and Brownian motion mechanisms, yielding a sediment settling velocity. The empirical portion of the model used this settling velocity, along with suspended solids, and flow field data to characterize sediment action. The remaining PCB transport mechanisms (volatilization and sorption) are theoretically considered to give a complete contaminant transport assessment. The PCBs in New Bedford Harbor tend to volatilize at the rate of 5.9 g/d; or sorb, with sorption coefficients increasing with percent chlorination from 10 Ϫ2.2 to 10 Ϫ0.4 m 3 /g for Aroclors 1016 and 1260, respectively, rather than stay in solution. The deterministic model showed that fluid shear was the most significant flocculation mass removal mechanism contributing to the settling velocity calculation. From the empirical model, the dominant sediment action mechanisms, resuspension and deposition, were driven by the change in suspended solids concentration and tides. The cycling of PCB-laden sediment, indicated by the PCB sorption tendency and the presence and dominance of resuspension, and subsequent transport from the site, can lead to PCB contamination of the water column, atmosphere, or downstream (marine) areas.

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“…• molecular surface area (7,9,(38)(39)(40)(41)(42) m solvametric parameters (43)(44)(45) Although the UNIFAC method and various modifications of the Seatchard-Hildebrand techniques employ sound thermodynamically derived components, several approaches employ only an appropriate amount of chemical intuition in combination with multiregressional analysis. In this review, we summarize some of the efforts that have been applied toward predicting aqueous activity coefficients of halogenated aromatic hydrocarbons of environmental interest.…”

Section: For a Solid The Equation Of Equilibrium For An Ideal Solutimentioning

confidence: 99%

Methods for Estimating Solubilities of Hydrophobic Organic Compounds: Environmental Modeling Efforts

Andrén

Doucette

Dickhut

1987

Sources and Fates of Aquatic Pollutants

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A variety of environmental fate models that integrate physicochemical properties of pollutants with advective and diffusive transport equations are now available. To satisfy the demand for missing input data, scientists have begun to incorporate property estimation techniques as part of their computational procedures. The recent appearance of high quality solubility data for polyhalogenated organic compounds makes it possible to evaluate several predictive schemes for these compounds. In this work, a brief review of the thermodynamics of hydrophobic compound solubility relationships is presented. This review is followed by an examination of the UNIFAC activity coefficient prediction technique. The use of octanol-water partition coefficients, total molecular surface areas, and molecular connectivity indexes to predict aqueous solubilities is then examined, and the resulting correlations are presented. MATHEMATICAL MODELING OF CHEMICAL FATE

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Henry's law constants for the polychlorinated biphenyls

Cited by 124 publications

References 29 publications

Surface Exchange and Transport Processes Governing Atmospheric PCB Levels over Lake Superior

Surface Exchange and Transport Processes Governing Atmospheric PCB Levels over Lake Superior

Fate and transport of pcbs at the new bedford harbor superfund site

Methods for Estimating Solubilities of Hydrophobic Organic Compounds: Environmental Modeling Efforts

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