Effect of native and exogenous humic substances on adsorption of PAHs on soils.

The fate of polycyclic aromatic hydrocarbons (PAHs) in nature is of great i mportance due to their toxic, mutagenic, acid carcinogenic properties(1). T heir presence in the environment is due to both natural diseases, such as f orest fires, and anthropic activities, such as urban and industrial process es. The kinetic of PAHs degradation has been related to both their chemical properties and to the chemical-physical properties of environmental matric es in which they are found(2,3,4,5,6,7,8). In order to understand the effect of humic substances or natural organic ma tter on the environmental suitability of PAHs in soils, soils treated with increasing rates of exogenous humic substances were studied. Moreover, the effect of native soil organic matter was also investigated.