The objective was to determine if biphenyl exposure alters the metabolic function or genetic structure of Lake Superior microbial communities. Biphenyl concentration was measured using HPLC followed by uv detection at 254 nm. A sterilized control was maintained to track non-biological breakdown of biphenyl and to estimate contamination from airborne bacteria due to sampling procedures. At termination the control and exposed microbial communities were filtered onto 0.22 m m Nucleopore TM filters and frozen. Community metabolism was evaluated using 3 H-leucine uptake data and Biolog GN MicroPlate TM patterns.
Preliminary results suggest a dose-dependent effect on cell number and leucine uptake.
The Biolog data do not reveal differences in community metabolic patterns. Genetic effects due to exposure to biphenyl will be assessed using a labeled gene probe based on the bacterial gene for biphenyl degradation. Jeff Denny US EPA 6201 Congdon Blvd.