Henry's Law Constants for Eleven Polychlorinated Biphenyls at 20 °C

Abstract

Henry's law constants for 11 polychlorinated biphenyls (PCBs) were measured using a gas purge system at 20 °C. The studied PCB congeners ranged from 2,4,4‘-trichlorobiphenyl to 2,2‘,3,4,4‘,5,5‘-heptachlorobiphenyl, spanning a range of hydrophobicities and solubilities, and including four mono-, and seven di-ortho-chlorinated compounds. For four PCBs, Henry's law constants have not been published before. These are 2,3,5,6-tetrachlorobiphenyl, 2,3,4,5,6-pentachlorobiphenyl, 2,2‘,3,4,4‘,5-hexachlorobiphenyl, and 2,3,3‘,4,4‘,5-hexachlorobiphenyl. For the lower chlorinated PCBs, the values are in agreement with available literature data. The values for the higher chlorinated PCBs agreed well with other partitioning data for PCBs and are lower than most available literature data. The measured Henry's law constants decreased with increasing hydrophobicity and showed a high correlation with the number and position of the chlorine atoms. The methods used are suitable for measuring reliable Henry's law constants and also for the higher chlorinated PCB congeners.

Polychlorinated biphenyls in air and water of the North Atlantic and Arctic Ocean

“…Determination of the key physico‐chemical parameters, notably the HLC required to make such an assessment, are subject to measurement difficulties and artifacts. Different methodologies have been used, which can be a source of variability in the reported data [ Bamford et al , 2002; Li et al , 2003; Goss et al , 2004; Baker et al , 2004; ten Hulsher et al , 2006].…”

“…The fugacity in the water (f w ) was calculated as where C W is the concentration of the compound in the dissolved phase (g m −3 ), and HLC is in Pa m 3 mol −1 . Owing to the large uncertainties in reported HLCs for PCBs, the fugacity in the water was estimated, using data from three different sources, namely Li et al [2003], Bamford et al [2002], and ten Hulsher et al [2006]. The HLC values were corrected for temperature and salinity, while the dissolved phase concentration was DOC corrected as reported elsewhere [ Totten et al , 2001].…”

“…Fugacity fractions of four PCB congeners (28, 52, 118, and 1380 versus latitude. Henry's Law constants were taken from Bamford et al [2002], Li et al [2003], and ten Hulsher et al [2006].…”

“…The fugacity quotients of PCBs ranged from 5 to 440, using the different published values for the different congeners [ Bamford et al , 2002; Li et al , 2003; ten Hulsher et al , 2006] with the highest positive ratio from 75°N to 79°N. Variability in the quotients was rather high (see Figure 4), caused mostly by variability in air concentrations, as water concentrations were more homogeneous.…”

Updated Abraham Solvation Parameters for Polychlorinated Biphenyls

“…Recently, experimental mono-and diortho-chlorinated PCB log K air-water values at 293 K were published by ten Hulscher et al (16), which were judged relatively accurate among a large number of experimental determinations using the gas-stripping method (17). Log K air-water values at 298 K can be estimated from the solvation equation given in eq 9.…”