FLUORESCENT POLYCYCLIC AROMATIC-HYDROCARBONS AS PROBES FOR STUDYING THE IMPACT OF COLLOIDS ON POLLUTANT TRANSPORT IN GROUNDWATER

A fluorescence-quenching method was developed to assess the hydrophobic organic pollutant binding potential of organic colloids (OC) in unaltered natural waters. This method allows (1) direct assessment of the importance of OC-enhanced pollutant transport for environmental samples under in situ water chemistry conditions, without requiring the isolation of OC or separation of equilibrated phases; (2) testing of chemicals that suffer substantial wall losses from aqueous solutions; and (3) examination of unstable water samples such as anoxic samples. Our experiments show that some OC (Aldrich humic acids) fully quench OC-associated perylene fluorescence, but others (bovine serum albumin) do not. This implies that fluorescence-quenching results collected for a single [OC] or over a limited [OC] range provide only a lower limit estimate of the potential for OC association. Tests with groundwater, recharged with secondarily treated sewage and containing OC at ~1 mg of C/L, showed temporal variation in the ability of OC present to quench or bind perylene. © 1990, American Chemical Society. All rights reserved.