USE OF CONVENTIONAL METHODS AND WHOLE-CELL HYBRIDIZATION TO MONITOR THE MICROBIAL RESPONSE TO TRIETHYLPHOSPHATE

The effect of triethylphosphate (TEP) on the activity of a landfill aq uifer microbial community was evaluated using standard techniques and in situ hybridizations with phylogenetic probes. Benzene was used as a n external carbon source to monitor degradation of an aromatic compoun d in TEP amended microcosms. Microscopic and viable counts were higher in TEP containing microcosms when compared to unamended controls. A s ignificant increase in ribosomal activity was also observed for TEP am ended samples as determined by the number of cells hybridizing to an e ubacterial probe. In addition, the number of beta and gamma Proteobact eria increased from undetectable levels prior to the study to 15-29% o f the total bacteria in microcosms containing TEP and benzene. In thes e microcosms, nearly 40% of the benzene was degraded during the incuba tion period compared to less than 5% in unamended microcosms. While TE P has previously been used as an alternate phosphate source in the bio remediation of chlorinated aliphatics, this study shows that it can al so stimulate the microbial degradation of aromatics in phosphate limit ed aquifers. (C) 1997 Published by Elsevier Science B.V.; copyright he ld by the U.S. government.