Leaking underground storage tanks and pipelines are some of the largest contributors to point source contamination of groundwater. The monoaromatic hydrocarbons benzene, ethylbenzene, toluene, and xylene (BETX's) are the hardest to manage if groundwater contamination occurs. This research project examined the role of nitrate as an alternate electron acceptor for biologically mediated reactions important to in situ biorestoration. Batch column study results showed no degradation of benzene, ethylbenzene, nor p-xylene observed over a one-hundred day period. No decrease in nitrate was observed as well. Results from the control reactor suggests that abiotic removal mechanisms such as sorption are negligible. Toluene degradation was observed when fed alone and in the mixture, and a concomitant decrease in nitrate was also observed. The research suggests that the presence of the non degraded BETX's has no apparent affect on the degradation of toluene. Additional research was funded by the Iowa State Water Resources Research Institute.