Multivariate Analysis of Community Structure Over Ten Years Following the Exxon Valdez Oil Spill

ABSTRACT A 1990/1991 shoreline ecology program to assess the fate and effects of the Exxon Valdez oil spill in Prince William Sound was updated in 1998 and 1999. This update included a sediment sampling program for organisms at “worst case” sites and at randomly chosen reference sites. Correspondence analysis (CA), a statistical method that examines animal communities in terms of their similarity, was used to define community structure Statistical analysis of the degree of similarity between communities was used to assess effects of site-specific variables (sediment grain size, total organic carbon (TOC) and wave energy), interannual variation, and degree of oiling. Interannual variability had a significant effect on community structure, whereas site specific variables and degree of oiling did not. Differences in communities between 1998 and other years were particularly dramatic. The importance of interannual change demonstrates the importance of multi-year sampling and of appropriate study designs for separating impact effects from the natural occurring environmental factors which affect biological communities.

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Oil Weathering and Sediment Toxicity in Shorelines Affected by the Exxon Valdez Oil Spill in Prince William Sound, Alaska

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2001-1-551 ◽

2001 ◽

Vol 2001 (1) ◽

pp. 551-557 ◽

Cited By ~ 2

Author(s):

David S. Page ◽

Edward S. Gilfillan ◽

William A. Stubblefield ◽

Paul D. Boehm ◽

Keith R. Parker ◽

...

Keyword(s):

Oil Spill ◽

Sediment Toxicity ◽

Sediment Quality ◽

Mortality Data ◽

Prince William Sound ◽

Exxon Valdez ◽

Sediment Grain Size ◽

Exxon Valdez Oil Spill ◽

Field Samples ◽

Polycyclic Aromatic

ABSTRACT Beginning in 1989, scientists supported by ExxonMobil conducted a number of scientific studies to assess the fate and effects of the Exxon Valdez oil spill on shorelines in Prince William Sound (PWS), Alaska. The 1990, 1991, and 1993 field programs included concurrent sediment sampling for hydrocarbon chemistry and sediment toxicity. This sediment quality assessment found that spill residues on the oiled shorelines rapidly lost toxicity through weathering. The relative amounts of naphthalenes and chrysenes in the polycyclic aromatic hydrocarbons (PAH) in the sediments were found to be good indicators of weathering and toxicity. Using a standard sediment amphipod bioassay on the field samples increased mortality above background was found at exposure levels above approximately 2,600 ng/g total PAH (TPAH) for oil that had weathered a year or more. For samples with TPAH > 2,600 ng/g, fractions of naphthalenes (R = +0.76) and chrysenes (R = −0.63) significantly correlated with amphipod mortality where samples with high mortalities (> 80%) were dominated by relatively high fractions of naphthalenes (median = 0.26), and the low mortality category (< 30%) was dominated by relatively high fractions of chrysenes (median = 0.24). The amphipod mortality data fit significantly to a logistic model. Estimated LC10 and LC50 values were approximately 4,100 and 10,750 ng/g TPAH, respectively. Sediment grain size and total organic carbon were also found to contribute to increased amphipod mortality and were covariates in the data analysis. As petroleum weathers through exposure to the environment and lighter hydrocarbon fractions are lost, the results of this study show that the Exxon Valdez spill oil rapidly lost toxicity as the fractions of chrysenes increased and fractions of naphthalenes decreased.

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The Role of Petroleum Geochemistry in Defining Oil Spill Recovery: Examples from the Exxon Valdez Spill in Prince William Sound, Alaska

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2003-1-291 ◽

2003 ◽

Vol 2003 (1) ◽

pp. 291-298

Author(s):

David S. Page ◽

A. Edward Bence ◽

William A. Burns ◽

Paul D. Boehm ◽

John S. Brown

Keyword(s):

Oil Spill ◽

Marine Environment ◽

Sediment Quality ◽

Quality Data ◽

Prince William Sound ◽

Exxon Valdez ◽

Worst Case ◽

Exxon Valdez Oil Spill ◽

Infaunal Community ◽

Petroleum Geochemistry

ABSTRACT The application of petroleum geochemistry to determining the fate and effects of oil spills in the marine environment requires high quality data to allow source identification through fingerprinting methods and unbiased sampling designs that allow valid comparisons to be made to detect spill related effects in the presence of other sources of environmental stress. This is particularly important in long-term studies, where sources of hydrocarbons and other pollutants unrelated to the spill event and non-spill related environmental effects become far more important in defining the environmental status of the spill zone. In studies of the Exxon Valdez oil spill, petroleum geochemistry is used to identify the many sources contributing polycyclic aromatic hydrocarbons (PAH) to the marine environment of Prince William Sound (PWS), including the Exxon Valdez oil spill, oil seep residues, particulates from eroding organic shales and coal formations, forest fire fallout, recent biogenic inputs and past human and industrial activities. A sediment quality triad-based shoreline ecology program (SEP), begun in 1990, includes a random sampling component and worst-case non-random site component that provides chemistry data through 2001 to determine the fate and bioavailability of spill oil residues on the shorelines. Environmental half-life values for the PAH at oiled sites range from 2.0 – 7.4 months for upper intertidal areas. Analysis of mussel tissue samples collected at worst-case spill locations find PAH concentrations in the same range as reference site samples. The results of concurrent sediment toxicity measurements using standard bioassays defines a dose-response relationship for total PAH concentration (TPAH) having a threshold of effect TPAH of 2,600 ng/g (dry wt.) that agrees well with the onset of sublethal ecological stress as defined by reductions in infaunal community structure parameters.

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A Comparison of Shoreline Assessment Study Designs Used for the Exxon Valdez Oil Spill

Marine Pollution Bulletin ◽

10.1016/s0025-326x(98)00138-6 ◽

1999 ◽

Vol 38 (5) ◽

pp. 380-388 ◽

Cited By ~ 6

Author(s):

E.S Gilfillan ◽

E.J Harner ◽

J.E O'Reilly ◽

D.S Page ◽

W.A Burns

Keyword(s):

Oil Spill ◽

Exxon Valdez ◽

Exxon Valdez Oil Spill ◽

Assessment Study ◽

Study Designs

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Profiles of Fecal Porphyrins in River Otters Following the Exxon Valdez Oil Spill

Marine Pollution Bulletin ◽

10.1016/s0025-326x(00)00073-4 ◽

2000 ◽

Vol 40 (12) ◽

pp. 1132-1138 ◽

Cited By ~ 8

Author(s):

Christopher Taylor ◽

Lawrence K Duffy ◽

R Terry Bowyer ◽

Gail M Blundell

Keyword(s):

Oil Spill ◽

Exxon Valdez ◽

Exxon Valdez Oil Spill ◽

River Otters

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Sublethal effects of the (Exxon Valdez) oil spill on herring embryos and larvae: morphological, cytogenetic, and histopathological assessments, 19891991

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f96-174 ◽

1996 ◽

Vol 53 (10) ◽

pp. 2355-2365 ◽

Cited By ~ 9

Author(s):

J E Hose ◽

M D McGurk ◽

G D Marty ◽

D E Hinton ◽

E D Brown ◽

...

Keyword(s):

Oil Spill ◽

Sublethal Effects ◽

Exxon Valdez ◽

Exxon Valdez Oil Spill

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EFFORT TO RESCUE OTTERS AFTER SPILL IS IN DISPUTE

PEDIATRICS ◽

10.1542/peds.88.3.661 ◽

1991 ◽

Vol 88 (3) ◽

pp. 661-661

Author(s):

J. F. L.

Keyword(s):

Crude Oil ◽

Oil Spill ◽

Preliminary Data ◽

Scientific Information ◽

Research Projects ◽

Exxon Valdez ◽

Sea Otters ◽

Exxon Valdez Oil Spill ◽

Rehabilitation Centers ◽

Government Contract

ANCHORAGE, April 20—Sea otters rescued from waters fouled by the Exxon Valdez oil spill fared poorly after their return to the wild last fall, and scientists working under Government contract say at least half may have perished over the winter. Nearly 900 dead otters were found after the tanker spilled almost 11 million gallons of crude oil in March 1989. An additional 360 were netted alive and brought to rehabilitation centers at Valdez, Seward, Homer and Kodiak. About 200 were later returned to Prince William Sound but some scientists say that as many as half may have perished and that the rehabilitation effort has been largely futile... The withholding of scientific information on the spill for legal reasons by all the parties is becoming a major source of controversy as research projects begin to generate at least preliminary data.

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