Environmental Measurement Symposium 2017

Transcription

1 Environmental Measurement Symposium 2017 Red Crabs As Sentinel Organisms of Deepwater Horizon Oil in Gulf of Mexico Sediments Gregory Douglas, Ph.D., Bo Liu, Jeffery Hardenstine "The views expressed herein do not necessarily represent the views of the U.S. EPA, NOAA or the United States."

2 Deep Water Horizon Blowout April 20, Million Gallons of Macondo Oil Photo Credits: 1. Image taken from video footage recorded by the BP Remotely Operated Vehicles (ROVs) and provided to the Government's Flow Rate Techncial Group (FRTG) for use in estimating the flow rate of the Deepwater Horizon oil spill. Credit: Courtesy U.S. Geological Survey 2.

3 Oil Trapped in Bacteria-Derived Mucus Agglomerates in the Deep-Sea Plume mucus-encapsulated oil at 1243 m; µm diam. free-floating, deep-sea mucus strands at 1115 m; m long Photos are provided compliments of Dr. James Payne from Payne Environmental Consultants, Inc.

4 Deep-Sea Sediment Assessment Photos are provided compliments of Dr. James Payne from Payne Environmental Consultants, Inc.

5 Conceptual Model for Seafloor Deposition Stout, S.A. and Payne, J.R. Macondo Oil in Deep-Sea Sediments: Part 1 Sub-sea Weathering of Oil Deposited on the Seafloor, Mar. Pollut. Bull.; 2016; 111, (2016)

6 Progression in Macondo Oil Weathering - Decalins and PAHs PAH become increasingly alkylchrysene rich, decalins to DBTsdepleted fresh oil PAH Histograms (Avg) (hopane-normalized) km (n=23) km (n=26) km (n=20) Stout, S.A. and Payne, J.R. Macondo Oil in Deep-Sea Sediments: Part 1 Sub-sea Weathering of Oil Deposited on the Seafloor, Mar. Pollut. Bull.; 2016; 111, (2016)

7 Progression in Macondo Oil Weathering - Biomarkers Biomarker Histograms (Avg) km (n=23) TRITERPANES hopane fresh oil STERANES TAS Selected individual biomarkers become depleted km (n=26) km (n=20) Stout, S.A. and Payne, J.R. Macondo Oil in Deep-Sea Sediments: Part 1 Sub-sea Weathering of Oil Deposited on the Seafloor, Mar. Pollut. Bull.; 2016; 111, (2016)

8 Core-Based Macondo Oil Seafloor Footprint ( ) 196 (27%) of the cores were clearly impacted by Macondo oil ( / ) Spier et al. (2013) deep plume detection frequency ~30 km 16 km direct fallout near well wax-rich, severelyweathered oil deposited as oily floc (MOS) away from the well preferentially to west and SW (30 km) 154 (21%) of the cores were impacted by seep oils ( ) localized impact and distinguishable from Macondo oil

9 Red Crab Anatomy Red Crab Anatomy with carapace removed identifying hepatopancreas. Red crab photo is provided by Barbara Viskup and Harriet Perry from South Regional Office of Mississippi Department of Environmental Quality at Biloxi, MS.

10 Red crab hepatopancreas m/z 191 pre and post HPLC

11 PAHs normalized to C4-Chrysenes in fresh Macondo oil and red crab hepatopancreas Off Scale Macondo Oil (Solid) Hepatopancreas (Pattern)

12 m/z 191, 217, 218 in fresh Macondo oil and red crab hepatopancreas

13 Biomarkers normalized to T19 in fresh Macondo oil and red crab hepatopancreas

14 Sample Analysis & Classification Conventional Hydrocarbon Analysis DCM extract/silica-alumina and or HPLC cleanup GC/MS (PAH & biomarkers) - TPAH49 = S N0-GHI - triterpanes, steranes, triaromatic steroids (TAS) Forensic Classification Macondo oil Seep oils Regional background Weight-of-Evidence Forensic Method Chemical fingerprinting Lateral and vertical concentration trends Fingerprint Classification A B C D E Description Chemical fingerprints are consistent with weathered Macondo oil Chemical fingerprints are mostly consistent with weathered Macondo oil with any differences being reasonably attributable to low(er) concentrations, the effects of very severe weathering, and/or obvious interferences Chemical fingerprints are affected by mixing, interferences, or metabolic effects, although some Macondo oil may be present; Concentrations often low Chemical fingerprints are inconclusive, most often due to a very low hydrocarbon concentrations, or high proportion of background Chemical fingerprints are inconsistent with fresh or weathered Macondo oil and not attributable to weathering and/or mixing (i.e., a different type of oil is present) Practical Conclusion Macondo crude oil is present Equivocal; Macondo crude oil is possibly present No Macondo crude oil or indeterminate due to low target concentration Macondo oil is not present but a different petroleum is present

15 Red Crab PAH & Biomarker Patterns Versus Tissue Type

16 Red Crab PAH & Biomarker Patterns Versus Distance From Blowout

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18 Changes In TPAH49 Red Crab Hepatopancreas Concentrations From 2011 to 2014.

19 Conclusions 1. The red crab hepatopancreas samples provided the most sensitive and diagnostic chemical fingerprints by which to assess exposure of these animals. 2. The highest exposures of red crabs to Macondo oil occurred closest to the well although exposures up to 14 km southwest of the well were identified. 3. Detection of Macondo Oil residuals in red crab tissue was consistent with spatial distribution of spill impacted sediments. 4. Red crab exposure to the Macondo Oil was substantially lower four years after the release.

20 Acknowledgements Sample Collections: numerous Chief Scientists and countless field staff Sample Analysis: Greg Baker, Wendy Wong, Eric Litman, Nancy Rothman, Alpha Analytical Staff Database: George Desreuisseau, Ann Jones Scientific Discussion: Scott Stout, Rob Ricker, Topher Lewis, Bill Driskell, Jim Payne GIS: Bo Liu, Gang Hu Funding: NOAA Photos are provided compliments of Dr. James Payne from Payne Environmental Consultants, Inc.