Bioremediation of Petroleum Impacted Salt Marsh Sediments – Initial Results

Jill Ghelerter
Georgia State University, Department of Geosciences Atlanta, Georgia, USA
[email protected]

Bioremediation is the preferred cleanup approach to petroleum impacted salt marshes. However, current technologies have led to inconsistent results. Application of clay minerals may be an innovative approach to bioremediation enhancement. Laboratory studies that involved clay minerals and oiled seawater have shown significant results but are limited. High layer charged montmorillonites were most effective. One suggested mechanism is the charge attraction between clay and the bacterial cell which allows weakly bonded hydrocarbons to be digested by the bacteria. Clay minerals have not been tested on oiled marsh sediments, despite the great impact that spilled oil has had on coastal marshes. In this study, biodegradation of Total Petroleum Hydrocarbons is being evaluated by comparing the effectiveness of natural attenuation to bioremediation in oiled salt marsh sediments enriched in montmorillonite or kaolin clay minerals. Investigation is being conducted in aerobic microcosms under controlled laboratory conditions for one year. Microcosms consist of field collected salt marsh sediments and seawater that were spiked with diesel oil. Selected microcosms were amended with either montmorillonite or kaolin, and the remaining microcosms are controls (natural attenuation). Samples were analyzed for saturated hydrocarbons using gas chromatography – flame ionized detection. Montmorillonite on the degradation of Total Petroleum Hydrocarbons was more effective than natural attenuation after 107 days. Results for the light (C9-C23) and heavy (C23-C40) normal alkanes, were 46% and 42%, respectively. Initial data suggests application of clay minerals may be an effective alternative to current bioremediation practices; additional data will test the model as the experiment proceeds.

AAPG Search and Discovery Article #90157©2012 AAPG Foundation 2012 Grants-in-Aid Projects