The sorption of fluoranthene on 4 soils and lava was studied without any cosolvent involed. The adsorption equilibrium was found to be established within 1 hour for both soil and lava. Strong linear isotherms were found in all adsorption experiments and the distribution coefficients (K d ) were highly correlated with the organic carbon contents. log K o c for all four soils was in good agreement with that predicted from the octanolwater partition coefficient (K o w ) and the aqueous solubility (S w ) of fluoranthene. An inverse temperature dependence was observed and the extent of adsorption decreased with the increase of temperature was predictive of ΔH e s , which denotes the enthalpic contribution to excess free energy of aqueous solution.