Tuesday, November 6, 2007 - 2:30 PM
230-14
Binding of Xenobiotics to Dissolved Organic Matter Originated from Treated Wastewater: Effect on Mobility of Pollutants in Soil.
Benny Chefetz, Michal Sherman, Tali Ilani, and Tamara Polubesova. Hebrew University of Jerusalem, Department of Soil and Water Sciences, Rehovot, 76100, Israel
Recycled wastewaters are potentially important source of irrigation water in the Middle-East. The influx of relatively high dissolved organic matter (DOM) concentrations into soils can significantly affect sorption and transport behavior of organic compounds. In this study, treated wastewater and sludge DOM samples were fractionated to hydrophobic acid (HoA) and hydrophobic neutral (HoN) fractions. Both fractions were chemically characterized and their sorptive abilities for s-triazine herbicides and polycyclic aromatic hydrocarbons (PAHs) were studied. In addition, the effects of polyvalent metal cations on pyrene binding to HoA and HoN have been elucidated. For all solutes, greater binding was obtained for HoN as compared to HoA due to higher hydrophobicity, aromaticity, and larger molecular size of HoN. It appears that paraffinic domains within the HoA or HoN sorbents provided a hydrophobic environment, which assisted to the sorption of hydrophobic sorbates. Whereas the presence of polar functional groups in HoA reduced their affinity to interact with low polar organic compounds. The complexation of HoA with Cu2+, Al3+ and Fe3+ increased the binding of pyrene; however pyrene binding to HoN was not affected by the presence of metal cations. Column transport experiments indicated that HoN is a major structural DOM fraction, which enhanced movement of organic pollutants in soils. Our results demonstrated that HoA and HoN components can significantly affect transport of organic contaminants in soils irrigated with treated wastewater or amended with sewage sludge.