Determination of octanol-air partition coefficients and supercooled liquid vapor pressures of organochlorine pesticides.

Octanol-air partition coefficients (K(OA)) and supercooled liquid vapor pressures (P(L)) of nine organochlorine pesticides (OCPs) including p,p'-DDE, p,p'-DDD, o,p'-DDT, o,p'-DDE, o,p'-DDD, alpha-HCH, beta-HCH, gamma-HCH, delta-HCH were determined as functions of temperature using a gas chromatographic retention time method. Among them, the K(OA) of o,p'-DDE and o,p'-DDD and the P(L) of o,p'-DDE, o,p'-DDD, beta-HCH and delta-HCH were determined for the first time. The determined K(OA) and P(L) values of investigated compounds at 25 degrees C ranged from 3.14 x 10(7) (alpha-HCH) to 3.76 x 10(9) (p,p'-DDD), and 8.95 x 10(-4) Pa (p,p'-DDD) to 1.08 x 10(-1) Pa (alpha-HCH), respectively. The K(OA) and P(L) data were compared with published data. The K(OA) values of o,p'-DDT at 25 degrees C were 3.23 x 10(9), higher than o,p'-DDE (1.02 x 10(9)) and o,p'-DDD (2.01 x 10(9)), indicating o,p'-DDT were more preferred to partition in soil compared with the metabolites. The K(OA) values were lower and P(L) 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 K(OA) and decreasing P(L) values in order of alpha-HCH, gamma-HCH, beta-HCH, delta-HCH, o,p'-DDE, p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD. For each compound, the LogK(OA) decreased linearly with reciprocal absolute temperature, while LogP(L) 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 K(OA) and P(L) of a number of OCPs.