Nonvolatile dissolved organic carbon and diesel range organics concentrations measured in 2016 at the USGS crude oil study site near Bemidji, Minnesota, USA
Description
The Bemidji crude oil spill site is a long-term USGS study site to understand the fate of crude oil in the shallow subsurface. A description of the site can be found at https://mn.water.usgs.gov/projects/bemidji. In 2014 concentrations of non-volatile dissolved organic carbon (NVDOC) were three times higher than diesel range organics (DRO) in the contaminant plume*. This is important because most of the NVDOC in the plume is composed of partial transformation products of compounds from the crude oil that are not reflected in a DRO analysis. In 2016 we conducted a campaign to determine if DRO values continue to reflect only a fraction of the NVDOC. These data are the results of that campaign. A total of 25 wells were sampled for DRO and NVDOC in August, 2016. Three wells with long term records were included in the sampling: 530B, 515B, and 9316D. Wells sampled in 2016 but not in 2014 include two wells located 14 m from a down gradient lake (1217B and 1217C) and one well in the zone sprayed by oil (956).
*Bekins, B. A., Cozzarelli, I. M., Erickson, M. L., Steenson, R. A., and Thorn, K. A., 2016, Crude Oil Metabolites in Groundwater at Two Spill Sites: Groundwater, v. 54, no. 5, p. 681-691.