Abstract:

This roller tank experiment was conducted to support results in GRIIDC datasets R4.x263.000:0034 and R4.x263.000:0035. It investigates the dissolution of different oil compounds (n-alkanes and polyaromatic hydrocarbons) into the dissolved water phase after only 1 hour of rotation. The effect of the dispersant Corexit on the dissolution was investigated as well. No organisms were present in the tanks in this experiment. The aim was to gain additional information on oil compound dissolution, since it was found to be of importance for oil incorporation into marine oil snow.

Suggested Citation:

Uta Passow, Marisa Wirth, D. Schulz-Bull. 2017. Component-specific Investigation of Oil Distribution in Seawater - Partitioning of oil in the absence of biota : Control tank data after 1 hour. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7Q52N25

Publications:

Wirth, M. A., Passow, U., Jeschek, J., Hand, I., & Schulz-Bull, D. E. (2018). Partitioning of oil compounds into marine oil snow: Insights into prevailing mechanisms and dispersant effects. Marine Chemistry, 206, 62–73. doi:10.1016/j.marchem.2018.09.007

Purpose:

Control roller tank experiment to test the partitioning of oil compounds in the absence of biota.

Data Parameters and Units:

a. Tank number b. Treatment= different treatments and controls were prepared (MilliQ Control = control tank containing only MilliQ water, Seawater Control = control tank containing only artificial seawater, O = Oil treatment, OC = Oil and Corexit treatment) c. Sample Type = only the DP = dissolved water phase (everything that passes through a 0.7 µm filter) was sampled (compared to Exp1-R4.x263.000:0034 and Exp2-R4.x263.000:0035) d. Sample volume (L) e. Entire fraction volume (L) f. Naph = Naphthalene (ng/mL) g. Acy = Acenaphthylene (ng/mL) h. Ace = Acenaphthene (ng/mL) i. Fl = Fluorene (ng/mL) j. Phen = Phenanthrene (ng/mL) k. Ant = Anthracene (ng/mL) l. Fluo = Fluoranthene (ng/mL) m. Pyr = Pyrene (ng/mL) n. BaA = Benzo(a)anthracene (ng/mL) o. Chr = Chrysene (ng/mL) p. BbF = Benzo(b)fluoranthene (ng/mL) q. BkF = Benzo(k)fluoranthene (ng/mL) r. BaP = Benzo(a)pyrene (ng/mL) s. Ind = Indeno(1,2,3-c,d)pyrene (ng/mL) t. DBA = Dibenzo(a,h)anthracene (ng/mL) u. BP = Benzo(g,h,i)perylene (ng/mL) v-az. Cx = n-alkane with x C-atoms and 2x+2 H-atoms

Methods:

Eight tanks (MilliQ control, Seawater control and three replicates for O and OC treatments) were filled bubble free with MilliQ water (MilliQ control) or artificial seawater (Seawater control and O and OC treatments; salinity 7.4 PSU) and sealed. The MilliQ and Seawater control remained unchanged, but oil or oil and Corexit were slowly injected into the center of the already rotating tanks of the O and OC treatments. For the O treatments, 50 µl of oil (Marlin Platform, Dorado source oil) and 20 µl of MilliQ water were injected. For the OC treatments, 50 µl of oil, 3 µl of Corexit (Clean Seas) and 20 µl of MilliQ water were used. All tanks were incubated in the dark on the roller tables for 1 hour. The temperature was 24.3 °C. For sampling, tanks were removed roller tables and the contents mixed. Subsamples from the oil-containing water were subsequently taken and filtered onto 0.7 µm borosilicate glass filters (Whatman, UK). The filter cakes were discarded and only the filtrate, termed dissolved phase (DP) was processed. For n-alkane and PAH analysis, DP samples were mixed with 225 µl of deuterated internal PAH standard solution (LGC Standards, UK). The samples were extracted twice with 10 mL dichloromethane (Prochem, Germany) and once with 10 mL hexane (Prochem, Germany) for 10 minutes each. The extracts were combined, dried over sodium sulfate (Merck, Germany) and concentrated to about 1 mL trough rotary evaporation. Subsequently, the solutions were purified over an aluminum oxide (Merck, Germany) and silica gel (Merck, Germany) column. The column was conditioned with 10 mL toluene (Prochem, Germany) and 10 mL heptane (Prochem, Germany). Analytes were eluted with 15 mL heptane and 30 mL of a heptane toluene mixture (2:1). The purified extracts were again concentrated to 1 mL. The samples were measured for PAHs using a Trace DSQ GC-MS system (Thermo Scientific, Germany) equipped with an electron impact ionization source and single quadrupole detector that operates in the SIM mode. The compounds were separated with a 60 m DB-5MS column (Agilent, U.S.). The following PAHs were targeted: Naphthalene (Naph), Acenaphtylene (Acy), Acenaphthene (Ace), Fluorene (Fl) Phenanthrene (Phen), Anthracene (Ant), Fluoranthene (Fluo), Pyrene (Pyr), Benz(a)anthracene (BaA), Chrysene (Chr), Benz(b)fluoranthene (BbF), Benz(k)fluoranthene (BkF), Benz(a)pyrene (BaP), Indeno(1,2,3-c,d)pyren (Ind), Dibenzo(a,h)anthracene (DBA) and Benz(g,h,i)perylene (BP). A self-prepared mixture of internal (deuterated) and external PAH standard (LGC Standards, UK) was measured alongside the samples and used for quantification. The samples were measured for alkanes using a Trace GC Ultra system (Thermo Scientific, Germany) equipped with an FID detector. The analytes were separated with a 30 m DB-5MS column (Agilent, U.S.). The n-alkanes from n-Decane (C10H22) to n-Tetracontane (C40H82) were targeted. An external n-alkane standard (Ultra Scientific, U.S.) was measured alongside the samples and used for quantification. Sample losses: An estimated 40 % of the oil did not get injected into O Tank 3

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