oa Magnetic Susceptibility Measurements as a Proxy for Bioremediation at Hydrocarbon Contaminated Sites

Magnetic susceptibility (MS) of sediments affected by hydrocarbon contaminated groundwater was studied at two sites. the sites used in the study are Bermidji MN, and Carson City, MI. Two cores were retrieved from Bemidji site; one from the contaminated area and the other from the background area. Three cores were collected from the Carson site; two within the contaminated area and one from the background area. All the cores that we collected extended from the unsaturated zone into the saturated zone. for the Bemidji site, there is a 0.9m hydrocarbon smear zone due to groundwater level fluctuations. for the Carson site, hydrocarbon smear zone is approximately 1-2 m. MS and Grain size data were collected from the cores from both sites. Our results show that MS increased towards the top of the GWT within the contaminated area of both sites. in contrast, the MS does not show any changes around the GWT within the clean cores of both sites. We postulate that this increase in MS is due to iron reducing microbes creating magnetite as a byproduct of hydrocarbon breakdown. Based on these results we conclude that the MS measurements can be used as a tool to investigate microbial activity within hydrocarbon contaminated zones.