The effect of the quality of soil organic matter on sorption of naphthalene

A set of soil samples varying in age, diagenesis, and kind and amount of organic matter were examined to study the influence of effective polarity and aromaticity of soil organic matter (SOM) on naphthalene sorption using batch equilibration.Aromaticity of organic phases of the soils was calculated from CPMAS 13C NMR spectrum data and the soil effective polarity was calculated using the equation developed by Xing et al. [12]. Concentration of naphthalene in solution was measured using liquid scintillation counting. The quality of SOM markedly influenced sorption of naphthalene. Old SOM in shale showed higher affinity for naphthalene than that in the surface, young soils.Sorption of naphthalene increased with increasing aromaticity and decreasing polarity.The sorption coefficient (Koc) of organic contaminants cannot be accurately predicted from their Kow without some consideration of SOM quality such as polarity and degree of aromaticity.