Many high molecular weight polycyclic aromatic hydrocarbons (PAH) are known or suspected carcinogens and as ubiquitous environmental pollutants, their remediation is necessary to reduce human and environmental health risk. Since PAH are biodegradable, bioremediation offers potential for site clean-up. Bioremediation techniques include in situ methods, or excavation followed by reactor treatment. To determine whether bacterial community diversity depends on treatment method, two incubation conditions were examined by stable isotope probing of pyrene-degrading bacteria in an aged PAHcontaminated soil. Microcosms of continuously mixed soil slurry or static, field-wet soil were spiked with [U-13C] pyrene and incubated in the dark at room temperature for 28 days. Recovered 13C-enriched DNA was analyzed by denaturing-gradient gel electrophoresis (DGGE) and 16S rRNA gene clone libraries. The minimal diversity observed between DGGE profiles suggests that pyrene-degrading bacterial community diversity may be independent of treatment method, though slurry libraries were slightly more diverse than field wet libraries
