Method for measuring the temperature dependence of the Henry's Law Constant of selected polycyclic aromatic hydrocarbons

The Henry's Law Constant (HLC) is an important thermodynamic constant neede d to model air-water exchange of contaminants such as polycyclic aromatic h ydrocarbons (PAHs). However, few direct HLC measurements have been reported for PAHs. A gas-stripping apparatus was constructed to allow gaseous and d issolved phase PAH concentrations to be measured over time. HLC was calcula ted by two methods: measuring PAH loss in the dissolved phase over time and dividing the instantaneous air by dissolved phase concentrations. Both met hods yielded similar HLC values that were comparable to the range of HLCs r eported in the literature.