Abstract:

This dataset reports gas chromatography/mass spectrometry (GC/MS) analytical results of water samples collected by Coastal Waters Consortium (CWC) researchers in southeastern Louisiana inland and coastal marshes and multiple R/V Pelican cruises (PE16-03, PE18-03, and PE19-04) in the Gulf of Mexico from 2015-05-12 to 2018-07-27. This dataset contains a master file containing all water sample collection information and total target alkane and aromatic concentrations for each sample, four excel files (organized by Principal Investigator) that provide individual concentrations of target alkane and aromatic analytes for all water samples listed in the master file, and an excel file providing the cruise ID for all water samples collected offshore on the R/V Pelican (The chief scientist for all cruises was Dr. Nancy Rabalais and data related to these cruises can be found in the R2R repository using the cruise ID). All files and data points can be linked using the LSU/RCAT ID number.

Suggested Citation:

Overton, Edward. 2019. Target alkane and aromatic concentrations for water samples collected in southeastern Louisiana inland and coastal marshes and multiple R/V Pelican cruises in the Gulf of Mexico from 2015-05-12 to 2018-07-27. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-kdeg-nj49

Publications:

Turner, R. E., Rabalais, N. N., Overton, E. B., Meyer, B. M., McClenachan, G., Swenson, E. M., … Zingre, J. (2019). Oiling of the continental shelf and coastal marshes over eight years after the 2010 Deepwater Horizon oil spill. Environmental Pollution, 252, 1367–1376. doi:10.1016/j.envpol.2019.05.134

Purpose:

In support of the Coastal Waters Consortium's effort to assess the chemical evolution, biological degradation, and environmental stresses of petroleum and dispersant within the Gulf of Mexico coastal and shelf ecosystems.

Data Parameters and Units:

File R6.x808.000-0043_Master_Waters_2015-2018_sub1.xlsx: LSU/RCAT ID# (Internal sample identifier assigned by the analytical lab), Date Sample Collected (MM/DD/YYYY), Date Sample Received in analytical lab (MM/DD/YYYY), Date Sample Extracted by analytical lab (MM/DD/YYYY), Date Sample Analyzed (MM/DD/YYYY), Extraction Method (Liquid-Liquid), Latitude (in decimal degrees), Longitude (in decimal degrees), Total Alkanes (µg/L), Total Aromatics (µg/L), Principal Investigator (CWC Principal Investigator by which or for which the sample was collected), Sample Description (user-defined descriptor for sample) and Concentration Workbook Filename (file with individual targeted alkane and aromatic analyte concentration data). N/A in any cell of the worksheet indicates the information was either not available or not applicable. Folder R6.x808.000-0043_Concentration_Workbooks_Waters_2015-2018: contains four excel files that provide individual targeted alkane and aromatic analyte concentrations for all water samples listed in R6.x808.000-0043_Master_Waters_2015-2018_sub1.xlsx. Data is organized by Principal Investigator (Mariotti, Rabalais, Robinson, Turner). Within each file, samples are grouped by LSU/RCAT ID# on different worksheets according to run batches (in other words, sequentially numbered batches of samples are on one worksheet tab). Format and Data Parameters and Units are the same for all files: LSU/RCAT ID# (Internal sample identifier assigned by the analytical lab), Field ID# (user-defined descriptor for sample), Initial Volume (mL; volume of water sample extracted), Final Extract Volume (µl; volume of extracted sample after concentration), surrogate corrected values for 28 alkane analytes (µg/l) and 43 aromatic analytes (µg/l). File Cruise_Sample_Info_Water_2015-2018.xlsx: contains the cruise ID and dates of sample collection for all water samples collected offshore on the R/V Pelican cruises PE16-03, PE18-03, and PE19-04.

Methods:

GC/MS-SIM water extraction (modified EPA SW-846 method 3510C): Separatory Funnel Liquid-Liquid extraction=procedure for isolating target alkanes and aromatics from aqueous samples with methylene chloride using a separatory funnel.

Instruments:

Nitrogen evaporator GC/MS

Error Analysis:

The Overton lab provided sample collection and storage guidelines to all coPI's. Data quality could be affected if these guidelines were not followed. Quality control samples were analyzed with each analytical sample sequence. These QC samples had to be within ±20% of the original calibration values. Extraction efficiency was evaluated based on the percent recovery of the surrogate standard added to each sample prior to extraction. The acceptable recovery range was 70-120%. Method blanks were also extracted with every extraction batch of 8 samples. Any alkanes and aromatics detected in the method blanks were surrogate corrected, averaged if multiple blanks were prepared for each sample batch, and subtracted out of the surrogate corrected concentrations of alkanes and aromatics in each water sample.

Individual Files: