Interaction of Polychlorinated Biphenyls with Dissolved Humic Acid from Azraq,Jordan

Humic acid is an important component of soil which was the subject of several environmental studies. Humic acid interact widely with environmental pollutants, such as chlorinated pesticides. Until now, the mechanism of interaction of humic acid with chemicals in the environment is not well defined. In this work the interaction behaviour of polychlorinated biphenyls (PCBs) with humic acid (HA) which was isolated from the Azraq Oasis (Jordan) was studied at different HA concentrations, pH and temperature. The amounts of the remaining PCBs were determined by extraction and analyzed on a capillary gas chromatograph equipped with a $^{63}$ Ni-electron capture detector (ECD). Generally the interacted amount of PCBs is directly proportional to the increase of soluble humic acid and inversely proportional to the increase of pH. The changes in temperature have no significant effect on the interacted amount of PCBs. The more chlorinated the PCBs are, the more the interaction is and the less the sensitivity for the changes in pH and HA concentration.