Abstract:
Crude oil is typically enriched in vanadium and nickel. Our objective is to determine if V and Ni enrichment in oil contaminated marine sediments and beach sands can be an effective proxy for mapping oil contamination. Crude oil from the Macondo blowout, marine sediments from the Gulf of Mexico, and beach sands from Pensacola, FL were digested and analyzed via ICP-MS. Our results show that beach sands exhibit V and Ni enrichment where visible and substantial oil contamination occurs. In contrast, lightly contaminated marine sediments do not. V and Ni content in marine sediments is related to Mn oxide in the sediment.
Suggested Citation:
Hastings, David. 2014. Trace and minor element content of beach sands affected by oil contamination in Pensacola, FL, June 2010 to July 2011.. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N71G0J79
Data Parameters and Units:
ppm = parts per million or µg / g of the elements [Ni, V, Co, Cu, Sr, Ba, Mo, Re, Fe, Cr, Mn, Zn, U], sample ID, location [Pensacola, St. George Island], description [heavily oiled, oiled, low oil, mid swash zone, high beach no oil]
Methods:
Beach sands were collected from beaches in the NW Florida Panhandle from June 3, 2010 to July 30, 2011. Samples were homogenized, freeze dried, then subsamples (~0.2 g) were weighed, and digested in a Milestone Ethos EZ microwave oven in closed digestion vessels with 10mL concentrated trace metal grade HNO3 at 175°C and high pressure (~25 bar) for 15 minutes according to standard methods (US EPA method 3051a). The digest was diluted 1:10 with MQ ultrapure H2O, and filtered with 0.45 µm PVDF syringe filters. Since HF is not used during the digestion, the digest does not include refractory components such as aluminosilicates, but will include authigenic phases, crude oil, organic phases, FeMn oxides, and carbonates. The samples were analyzed using an Agilent 7500cx ICP-MS with an octopole reaction cell in helium mode for V, Cr, Mn, Fe, Co, Ni, Cu, Sr, and Cd to reduce isobaric interferences and in no-gas mode for Mo, Ba, Re, and U. Prior to analysis, samples were spiked with an internal standard containing Ge, In, and Bi in order to correct for instrumental drift during analysis. Elemental concentrations were determined using a 6-point external calibration line.
Instruments:
The samples were analyzed at the ICP-MS facility at University of South Florida College of Marine Science with the assistance of Dr. Kelly A. Quinn. We used an Agilent 7500cx ICP-MS with an octopole reaction cell in helium mode for V, Cr, Mn, Fe, Co, Ni, Cu, Sr, and Cd to reduce isobaric interferences and in no-gas mode for Mo, Ba, Re, and U. Prior to analysis, samples were spiked with an internal standard containing Ge, In, and Bi in order to correct for instrumental drift during analysis.
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