Organic Contaminants, Trace and Major Elements, and Nutrients in Water and Sediment Sampled in Response to the Deepwater Horizon Oil Spill Open-File Report 2011–1271 U.S. Department of the Interior U.S. Geological Survey Organic Contaminants, Trace and Major Elements, and Nutrients in Water and Sediment Sampled in Response to the Deepwater Horizon Oil Spill By Lisa H. Nowell, Amy S. Ludtke, David K. Mueller, and Jonathon C. Scott Open-File Report 2011–1271 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2011 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Suggested citation: Nowell, L.H., Ludtke, A.S., Mueller, D.K., and Scott, J.C., 2011, Organic contaminants, trace and major elements, and nutrients in water and sediment sampled in response to the Deepwater Horizon oil spill: U.S. Geological Survey Open-File Report 2011-1271, 128 p. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. Contents Abstract ......................................................................................................................................................................... 1 Introduction .................................................................................................................................................................... 3 Methods ......................................................................................................................................................................... 4 Study Area and Site Selection.................................................................................................................................... 4 Sample Collection ...................................................................................................................................................... 5 Water Samples ....................................................................................................................................................... 5 Sediment Samples ................................................................................................................................................. 6 Chemical Analyses ..................................................................................................................................................... 6 Water ...................................................................................................................................................................... 7 Sediment ................................................................................................................................................................ 8 Quality Control Samples ............................................................................................................................................ 8 Blanks..................................................................................................................................................................... 8 Field Replicates .................................................................................................................................................... 10 Matrix Spikes ........................................................................................................................................................ 10 Laboratory Quality-Control Procedures ................................................................................................................ 11 Water- and Sediment-Quality Benchmarks .............................................................................................................. 11 Human-Health Benchmarks for Water .................................................................................................................. 12 Aquatic-Life Benchmarks for Water ...................................................................................................................... 12 Toxic-unit benchmarks for PAH-BTEX mixtures in water .................................................................................. 12 Marine benchmarks .......................................................................................................................................... 13 Sediment-Quality Benchmarks ............................................................................................................................. 13 EqP sediment benchmarks for PAH mixtures ................................................................................................... 14 EqP sediment benchmarks for individual contaminants .................................................................................... 14 Empirical sediment benchmarks ....................................................................................................................... 15 National Baseline Concentrations for Trace and Major Elements and Nutrients in Fine Sediment ....................... 16 Interpretation of Benchmark Exceedances ........................................................................................................... 17 Data Compilation...................................................................................................................................................... 17 Data Analyses .......................................................................................................................................................... 18 Results and Discussion ............................................................................................................................................... 20 Quality-Control Analyses .......................................................................................................................................... 20 Blank Samples ..................................................................................................................................................... 20 Field Replicates .................................................................................................................................................... 21 Matrix Spikes ........................................................................................................................................................ 22 Data Censoring ........................................................................................................................................................ 23 Censoring on the Basis of Quality-Control Results ............................................................................................... 23 Determination of Common Censoring Thresholds ................................................................................................ 24 Organic Contaminants in Water ............................................................................................................................... 26 Contaminant Occurrence ...................................................................................................................................... 26 Comparison of Pre-Landfall to Post-Landfall Samples ......................................................................................... 27 Comparison with Benchmarks for Human Health and Aquatic Life ...................................................................... 28 Organic Contaminants in Sediment .......................................................................................................................... 30 Contaminant Occurrence ...................................................................................................................................... 30 Comparison of Pre-Landfall to Post-Landfall Samples ......................................................................................... 31 Comparison with Benchmarks for Aquatic Life ..................................................................................................... 32 iii Contents—Continued Trace and Major Elements and Nutrients in Water ................................................................................................... 34 Constituent Occurrence ........................................................................................................................................ 34 Comparison of Pre-Landfall to Post-Landfall Samples ......................................................................................... 35 Comparison with Benchmarks for Human Health and Aquatic Life ...................................................................... 35 Trace and Major Elements and Nutrients in Sediment ............................................................................................. 37 Constituent Occurrence .......................................................................................................................................