PW13 Sediment Chemistry
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW208) Novel TPH pattern detected in samples from McMurdo Station, Antarctica.
Sweet, S1, Sericano, J1, Denoux, G1, Gielstra, D.1, Klein, A1, Kennicutt, II, M1, Qian, Y1, Wade, T1, Wolff, G1, 1 Texas A&M University, College Station, Texas, USA
ABSTRACT- Samples were collected to establish a long-term monitoring program for the area in and around the largest United States research station in Antarctica, McMurdo Station, with continuous occupation since 1955. Over a three-year period, more than 1500 soil samples were collected and analyzed for total petroleum hydrocarbons (TPH), trace metals, total organic, and total inorganic carbon. TPH concentrations and distributions are used as an indication of the spatial extent of various station activities. The linkage to activities is provided by the composition of the hydrocarbons detected and by the distribution of the contaminants in relation to locations of known sources (e.g., helicopter-pad, pipelines, storage tanks, etc.). The initial indications of the presence of hydrocarbons are elevated concentrations of TPH. This is followed by compositional analyses, designed to determine potential origins of these compounds. Compositional analysis discovered a novel TPH pattern, characterized by a cluster of peaks, in a significant number of samples. In the first year, 399 samples out of a total of 724 collected samples showed this novel TPH pattern. The concentrations of this cluster of peaks varied from less than one ppm to 628 ppm (average of 15.8 ppm; median of 51.4 ppm) in the first year. 224 out of 366 samples collected during the second year contained these peaks with a range from less than one ppm to 550 ppm (average of 22 ppm; median of 4.9 ppm). In the third year, 265 out of 466 samples contained these unknown compounds with concentrations ranging from less than one ppm to 997 ppm (average of 76.1 ppm; median of 17.6 ppm). The spatial distribution of this TPH signature appears associated with fuel storage and roadways. These components were confirmed to be mostly composed of hydrocarbons, by GC/MS analysis. The source of this novel distribution is currently unknown but is under investigation.
Key words: Antarctica, TPH, McMurdo, Contamination