Print this pageThe Effect of Brine on the Microbial Degradation of Hydrocarbons: A Progress Report from the Tallgrass Prairie Preserve, Oklahoma
SULLIVENT, KIMBERLY D.
The Tallgrass Prairie Preserve in Osage County Oklahoma represents a unique site for the study of the long term effects of brine and oil contamination. This study examines the role of brine contamination on the bioremediation of hydrocarbons in an abandoned storage pit.
Fifty samples were collected from the pit and the immediate outwash area where brine damage is obvious. Hydrocarbons were extracted from 25 samples and analyzed using standard gas chromatographic techniques. Each sample was tested for the percentage of total dissolved salts and bio-assayed to determine the microbial content.
The amount of degradation was determined using the least degraded sample as a standard. By comparing the remaining samples, a relative scale of degradation was established. The most degraded samples are along the pit edges where vegetation and soil depth are well established. The least degraded oils are located in areas of high total dissolved salts at the base of the pit where a man-made berm prevents dispersion of the brine. The samples were scored based on turbidity and emulsion. The highest microbial counts were also found along the pit edges, where nutrients and other physical requirements for growth are more abundant. Fungal growth occurred within 12 days of inoculation and was widespread within 30 days. Fungi are more salt tolerant, while the bacteria cannot survive in elevated salt concentrations. The results of the amount of degradation, total dissolved salts and most probable number show that brine is hindering microbial growth thus affecting the amount of oil degradation.