Abstract
Octanol-air partition coefficients (KOA) and supercooled liquid vapor pressures (PL) of nine organochlorine pesticides (OCPs) including p,p′-DDE, p,p′-DDD, o,p′-DDT, o,p′-DDE, o,p′-DDD, α-HCH, β-HCH, γ-HCH, δ-HCH were determined as functions of temperature using a gas chromatographic retention time method. Among them, the KOA of o,p′-DDE and o,p′-DDD and the PL of o,p′-DDE, o,p′-DDD, β-HCH and δ-HCH were determined for the first time. The determined KOA and PL values of investigated compounds at 25°C ranged from 3.14 × 107 (α-HCH) to 3.76×109 (p,p′-DDD), and 8.95×10− 4 Pa (p,p′-DDD) to 1.08×10− 1 Pa (α-HCH), respectively. The KOA and PL data were compared with published data. The KOA values of o,p′-DDT at 25°C were 3.23×109, higher than o,p′-DDE (1.02×109) and o,p′-DDD (2.01×109), indicating o,p′-DDT were more preferred to partition in soil compared with the metabolites. The KOA values were lower and PL values were higher for o,p′-DDE and o,p′-DDD, compared with their p,p′-isomeric counterparts, leading to a potential difference in behavior and fate of these isomers. The discrepancies among chemicals are obvious, which reflected in the increasing KOA and decreasing PL values in order of α-HCH, γ-HCH, β-HCH, δ-HCH, o,p′-DDE, p,p′-DDE, o,p′-DDD, o,p′-DDT, p,p′-DDD. For each compound, the LogKOA decreased linearly with reciprocal absolute temperature, while LogPL had a significant positive correlation with the inverse absolute temperature. The present study suggested that the method of gas chromatographic retention time was appropriate to measure the KOA and PL of a number of OCPs.
Acknowlegments
Funding for this study was provided by the High Technology Research and Development Program of China (No. 2007AA06Z412), National Basic Research Program (2007CB407303) and National Scientific Foundation of China (Grant 40730737 and 40771179).
Notes
*Values for logKOA- lit from Shoeib and Harner.[ Citation 10 ]
*Values for logPL- lit from Hinckley et al.[ Citation 20 ]