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 in the Gulf of Mexico from 2010-05-17 to 2014-08-01. This dataset contains a master file containing all water sample collection information and total target alkane and aromatic concentrations for each sample, five excel files (organized by sampling region) 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:
Ashton-Meyer, Buffy. 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 2010-05-17 to 2014-08-01. 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-czff-sm91
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: R4.x264.194-0001_Master_Oil_Dataset_Water_2010-2014_sub1.xlsx: LSU/RCAT ID#: Internal sample identifier assigned by the analytical lab, date sample collected (MM/DD/YYYY or MMM-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 (decimal degrees), longitude (decimal degrees), total alkanes (µg/L), total aromatics (ng/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 not available.
Folder R4.x264.194-0001_Concentration_Workbooks_Water_Data_2010-2014: contains five excel files that provide individual targeted alkane and aromatic analyte concentrations for all water samples listed in R4.x264.194-0001_Master_Oil_Dataset_Water_2010-2014_sub1.xlsx. Data is organized by sample location/region (Barataria watershed, Lake Pontchartrain, Mississippi River, offshore waters, unknown locations). 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#, field ID# (user-defined descriptor for sample), initial water volume (mL; volume of sample extracted), final extract volume (µl; volume of extracted sample after concentration), surrogate corrected values for 28 alkane analytes and 43 aromatic analytes (µg/l; concentrations are reported to three (3) significant figures). File Cruise_Sample_Info_Water_2010-2014.xlsx contains the LSU/RCAT ID#, sampling collection date, cruise id, and cruise vessel.
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.
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