Henry’s law constants for hexachlorobenzene, p,p′-DDE and components of technical chlordane and estimates of gas exchange for Lake Ontario

The Henry’s law constants (HLC) for trans- and cis-chlordane (TC, CC), trans-nonachlor (TN), hexachlorobenzene (HCB) and p,p′-DDE were determined by the gas-stripping method over a temperature range of 5–35 °C. The HLC variation versus temperature (K) was described by log H = m/T + b. Parameters of this equation were (with standard deviations) TC: m = −1524 ± 158, b = 6.58 ± 0.54; CC: m = −1786 ± 209, b = 7.42 ± 0.71; TN m = −2068 ± 284, b = 8.44 ± 0.97; HCB: m = −3013 ± 174, b = 11.60 ± 0.59 and p,p′-DDE: m = −2043 ± 240, b = 8.37 ± 0.82. The HLCs (Pa m3 mol−1) at 25 °C (298.15 K) were: TC = 29; CC = 27; TN = 32; p,p′-DDE = 33 and HCB = 35. These HLCs values were used to calculate fugacity ratios from paired air and water data from Lake Ontario, July 1998. The resulting fugacity ratios predict that volatilization was occurring for all compounds during that month.