Compilation, Evaluation, and Selection of Physical−Chemical Property Data for Organochlorine Pesticides

Abstract

Accurate physical−chemical properties (aqueous solubility SW, octanol−water partition coefficient KOW, vapor pressure P, Henry's law constant H, octanol−air partition coefficient KOA, octanol solubility SO) and their temperature dependence are of fundamental importance for interpreting and simulating the environmental fate and transport of organochlorine pesticides (OCPs). A complete set of property data for 14 organochlorine chemicals is derived by evaluating, averaging, and regressing all measured values reported in the literature. The 14 chemicals are hexachlorobenzene (HCB), pentachlorobenzene (PeCB), cis-chlordane, trans-chlordane, 1,1,1-trichloro-2,2-bis-4-chlorophenyl-ethane (p,p‘-DDT) and its metabolites 1,1-dichloro-2,2-bis-4-chlorophenyl-ethene (p,p‘-DDE) and 1,1-dichloro-2,2-bis-4-chlorophenyl-ethylene (p,p‘-DDD), heptachlor and its metabolite heptachlor epoxide, aldrin, dieldrin, endrin, α-endosulfan, and β-endosulfan. Properties for each individual chemical are adjusted to ensure thermodynamic consistency. That adjustment is sized according to, and is usually smaller than, the measurement uncertainty. Internal energies of phase transfer ΔU could be derived only for HCB and PeCB. The lack of property measurements as a function of temperature for the other chemicals prevents their ΔU values from being derived.