Using a database of 440 molecules, we develop a set of effective solvent de
scriptors that characterize the organic carbon component of soil and thereb
y allow quantum mechanical SM5 universal solvation models to be applied to
partitioning of solutes between soil and air. Combining this set of effecti
ve solvent descriptors with solute atomic surface tension parameters alread
y developed for water/air and organic solvent/air partitioning allows one t
o predict the partitioning of any solutes composed of H, C, N, O, F, P, S,
Ci, Br, and I between soil and water. We also present linear correlations o
f soil/water partitioning with 1-octanol/water partition coefficients using
the same database. The quantum mechanical calculations have the advantages
that they require no experimental input and should be robust for a wide ra
nge of solute functionality. The quantitative effective solvent descriptors
can be used for a better understanding (than with previously available mod
els) of the sources of different partitioning phenomena in cases where the
results exhibit significant fragment interactions. We anticipate that the m
odel will be useful for understanding the partitioning of organic chemicals
in the environment between water and soil or, more generally, between wate
r and soil or sediments (geosorbents).