Binding of Hydrophobic Organic Contaminants to Humalite-Derived Aqueous Humic Products, with Implications for Remediation

In order to assess the potential of commercial humic products in environmen-tal remediation, their binding to heptachlor, hexachlorobenzene, hexa-chloroethane, 1,2,4-trichlorobenzene and n-hexane was measured. The binding was similar in tests with two colloidal-phase humic products prepared from humalite (naturally occurring, oxidized organic deposits found adjacent to coal) from Alberta, Canada (Luscar Ltd.). There were minor or negligible changes in binding strength for these two products over the full range of aqueous concen-trations tested (1.67 to 33.4 g organic C/L), and for Aldrich humic acid. Aldrich humic acid was a stronger binder of the hydrophobic organic compounds than the two Luscar humic products, by factors of approximately 3 to 7. The binding of hydrophobic organics to the two Luscar humic products was similar in strength to that predicted for humic substances that occur in natural aquatic environments. Our binding data suggest that the use of concentrated Luscar humic products as colloidal-phase flushing agents would increase the aqueous concentrations of some hydrophobic organic contaminants in soils or aquifers by up to several hundred fold