Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Henry's law constants for α-, β-, and γ-hexachlorocyclohexanes (HCHs) as a function of temperature and revised estimates of gas exchange in Arctic regions
Abstract Henry's law constants (H, Pa m3 mol−1) were determined for α-, β-, and γ-HCH in deionized water over a temperature range of 5–35°C using bubble stripping (BS) and dynamic head space (DHS) techniques. The BS method was improved from previous work in the same laboratory by adjusting for loss of water from the stripping chamber over the experiment. This correction resulted in H values that were ∼15% lower than those calculated without volume adjustments. Good agreement between the BS and DHS methods was found for α- and γ-HCHs, with an average ratio of BS/DHS values = 0.99. H values at 20°C for α- and γ-HCH were 86–89% of those determined by Jantunen and Bidleman (Chemosphere, Global Change Science 2 (2000) 225), but only 62–69% of the results reported by Kucklick et al. (Marine Chem. 34 (1991) 197). The BS rate of β-HCH was much slower than for the other HCHs and its H was determined only by the DHS method. Enthalpies of water-to-air transfer, ΔHwa, were 59.3±1.6, 65.1 ± 1.3 and 61.4 ± 3.1 kJ mol−1 for α-, β- and γ-HCH, respectively. A reassessment of air–water gas exchange in the western Arctic Ocean and its regional seas was made, based on measurements in 1992–1994. α-HCH was significantly (p<0.05) oversaturated (net volatilization) in the south Bering Sea and Beaufort Sea but not significantly different from air–water equilibrium in the Chukchi Sea nor the northern Canada Basin. γ-HCH was significantly undersaturated (net deposition) in all four regions. This differs from previous estimates which indicated oversaturation of α-HCH in the four seas and air–water equilibrium for γ-HCH. β-HCH was oversaturated in the south Bering Sea, undersaturated in the Beaufort Sea and near equilibrium in the Chukchi Sea and northern Canada Basin. Highly accurate H values are required when estimating gas exchange in aquatic systems that are close to air–water equilibrium.
Henry's law constants for α-, β-, and γ-hexachlorocyclohexanes (HCHs) as a function of temperature and revised estimates of gas exchange in Arctic regions
Abstract Henry's law constants (H, Pa m3 mol−1) were determined for α-, β-, and γ-HCH in deionized water over a temperature range of 5–35°C using bubble stripping (BS) and dynamic head space (DHS) techniques. The BS method was improved from previous work in the same laboratory by adjusting for loss of water from the stripping chamber over the experiment. This correction resulted in H values that were ∼15% lower than those calculated without volume adjustments. Good agreement between the BS and DHS methods was found for α- and γ-HCHs, with an average ratio of BS/DHS values = 0.99. H values at 20°C for α- and γ-HCH were 86–89% of those determined by Jantunen and Bidleman (Chemosphere, Global Change Science 2 (2000) 225), but only 62–69% of the results reported by Kucklick et al. (Marine Chem. 34 (1991) 197). The BS rate of β-HCH was much slower than for the other HCHs and its H was determined only by the DHS method. Enthalpies of water-to-air transfer, ΔHwa, were 59.3±1.6, 65.1 ± 1.3 and 61.4 ± 3.1 kJ mol−1 for α-, β- and γ-HCH, respectively. A reassessment of air–water gas exchange in the western Arctic Ocean and its regional seas was made, based on measurements in 1992–1994. α-HCH was significantly (p<0.05) oversaturated (net volatilization) in the south Bering Sea and Beaufort Sea but not significantly different from air–water equilibrium in the Chukchi Sea nor the northern Canada Basin. γ-HCH was significantly undersaturated (net deposition) in all four regions. This differs from previous estimates which indicated oversaturation of α-HCH in the four seas and air–water equilibrium for γ-HCH. β-HCH was oversaturated in the south Bering Sea, undersaturated in the Beaufort Sea and near equilibrium in the Chukchi Sea and northern Canada Basin. Highly accurate H values are required when estimating gas exchange in aquatic systems that are close to air–water equilibrium.
Henry's law constants for α-, β-, and γ-hexachlorocyclohexanes (HCHs) as a function of temperature and revised estimates of gas exchange in Arctic regions
Sahsuvar, Liz (Autor:in) / Helm, Paul A. (Autor:in) / Jantunen, Liisa M. (Autor:in) / Bidleman, Terry F. (Autor:in)
Atmospheric Environment ; 37 ; 983-992
07.11.2002
10 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Biochemical Effects Induced by the Hexachlorocyclohexanes
| Springer Verlag | 2011
Henry's Law Constants for Carcinogenic Volatile Organic Compounds
| British Library Conference Proceedings | 2014
Prediction of Henry's Law Constants by Matrix Completion
| Wiley | 2022