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

2003 ◽  
Vol 2003 (1) ◽  
pp. 291-298
Author(s):  
David S. Page ◽  
A. Edward Bence ◽  
William A. Burns ◽  
Paul D. Boehm ◽  
John S. Brown

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.

2001 ◽  
Vol 2001 (1) ◽  
pp. 559-567 ◽  
Author(s):  
Edward S. Gilfillan ◽  
David S. Page ◽  
Keith R. Parker ◽  
Jerry M. Neff ◽  
Paul D. Boehm

ABSTRACT A shoreline ecology program was performed in Prince William Sound (PWS), Alaska in 1990 and 1991 (1 and 2 years after the Exxon Valdez oil spill, EVOS) to assess the fate and effects of the oil in the intertidal zone. Major components of the study were repeated in 1998 and 1999. This update included a sediment-sampling program at formerly oiled “worst-case” boulder/cobble (B/C) sites and randomly chosen unoiled B/C reference sites. The samples were analyzed for petroleum hydrocarbons and benthic infaunal community characteristics. This paper focuses on the results of the benthic infaunal community analysis. Analysis of Covariance (ANCOVA) was used to analyze the 1990–1999 infaunal species composition data. Very little effect of oiling was detected in either the analysis of community structure parameters or in individual species abundances. Oiling effects were detected at some sites in 1990 and 1991, but not in 1998 and 1999. Nearly all the change in intertidal community parameters between 1990 and 1999 was attributed to natural interannual variation. The composition of the intertidal community of B/C shores changed over time because of natural factors not related to the spill. A core group of species was found in each of the 4 years. This group of species represented between 9 to 30% of all species identified. Two other groups of species did not co-occur. One group was present in 1990 and 1991, but not in 1998 and 1999; the other group was present in 1998 and 1999, but not in 1990 and 1991. The progressive change in the animal community observed between 1990 and 1999 is very likely related to long-term climatic changes occurring in the study area and not the oil spill. This long-term study demonstrates the importance of study designs that allow separation of oiling effects from natural factors that can affect biological communities.


2001 ◽  
Vol 2001 (1) ◽  
pp. 551-557 ◽  
Author(s):  
David S. Page ◽  
Edward S. Gilfillan ◽  
William A. Stubblefield ◽  
Paul D. Boehm ◽  
Keith R. Parker ◽  
...  

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.


The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 723-737 ◽  
Author(s):  
David B. Irons ◽  
Steven J. Kendall ◽  
Wallace P. Erickson ◽  
Lyman L. McDonald ◽  
Brian K. Lance

Abstract We compared post Exxon Valdez oil-spill densities of marine birds in Prince William Sound from 1989–1991, 1993, 1996, and 1998 to pre-spill densities from 1984–1985. Post-spill densities of several species of marine birds were lower than expected in the oiled area of Prince William Sound when compared to densities in the unoiled area. These negative effects continued through 1998 for five taxa: cormorants, goldeneyes, mergansers, Pigeon Guillemot (Cepphus columba), and murres. Black Oystercatchers (Haematopus bachmani) and Harlequin Ducks (Histrionicus histrionicus) exhibited negative effects in 1990 and 1991. Loons showed a weak negative effect in 1993. Black-legged Kittiwakes (Rissa tridactyla) showed relative decreases in 1989, 1996, and 1998 which may have been caused by shifts in foraging distribution rather than declines in populations. Glaucous-winged Gulls (Larus glaucescens) showed positive effects in most post-spill years. Murrelets and terns showed relative increases in 1993, 1996, and 1998. Generally, taxa that dive for their food were negatively affected, whereas taxa that feed at the surface were not. Effects for some taxa were dependent upon the spatial scale at which they were analyzed. Movements of birds and the mosaic pattern of oiling reduced our ability to detect oil-spill effects, therefore our results may be conservative. Several marine bird species were negatively affected at the population level and have not recovered to pre-spill levels nine years after the oil spill. The reason for lack of recovery may be related to persistent oil remaining in the environment and reduced forage fish abundance.


1995 ◽  
Vol 10 (1-2) ◽  
pp. 137-156 ◽  
Author(s):  
Douglas A. Wolfe ◽  
K. John Scott ◽  
John R. Clayton ◽  
John Lunz ◽  
James R. Payne ◽  
...  

2003 ◽  
Vol 2003 (1) ◽  
pp. 285-289
Author(s):  
E.S. Gilfillan ◽  
D.S. Page ◽  
K.R. Parker

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.


1991 ◽  
Vol 1991 (1) ◽  
pp. 229-233
Author(s):  
Marjorie J. Gibson

ABSTRACT Despite initial concerns about the impact of the Exxon Valdez oil spill on bald eagles in Prince William Sound, accumulating evidence indicates that the area's eagle population is doing well. This paper presents and discusses the 1989 data collected during the Prince William Sound and Kodiak Island Eagle Capture and Short-term Rehabilitation Programs, as well as 1990 data from the U.S. Fish and Wildlife Service's operational field surveys.


1992 ◽  
Vol 19 (3) ◽  
pp. 253-258 ◽  
Author(s):  
David G. Shaw

Major oil-spills, such as occurred following the grounding of the tanker Exxon Valdez in March 1989 in Prince William Sound, Alaska, account for only a small fraction of the total anthropogenic input of petroleum to the marine environment. Yet major spills can result in significant and even acute impacts, trigger ecological changes requiring decades for recovery, and command considerable public attention. Thus catastrophic oil-spills in general, and the Exxon Valdez spill in particular, differ from other chronic human alterations of coastal marine systems.Estimates of the fate of the 38,000 metric tons of crude oil lost by the Exxon Valdez are imprecise, but perhaps 30–40% evaporated, 10–25% was recovered, and the rest remains in the marine environment. Roughly 1,500 km of coastline were oiled in varying degrees. Much of this coastline consists of gravel beaches into which oil penetrated to depths as great as 1 m.The ecological effects of the spill on the marine environments of Prince William Sound and adjacent coastal areas of the Gulf of Alaska were extensive, but natural recovery, aided by clean-up efforts, is expected. Judging by the consequences of other oil-spills affecting rocky shorelines, as well as previous natural and anthropogenic disturbances to Prince William Sound, it appears likely that most affected biotic communities and ecosystems will recover to approximately their pre-spill functional and structural characteristic within from five to twenty-five years.This oil-spill had major social effects. Many individuals, whether personally present or viewing the spill around the world on television, were saddened by the environmental damage, and felt that an important public trust had been broken. These feelings, together with dissatisfaction with the results of early clean-up efforts, gave rise to popular sentiment in favour of every possible clean-up and mitigation effort — regardless of cost, effectiveness, or possible negative consequences.The response to the Exxon Valdez oil-spill by government and the oil industry revealed serious inadequacies in the plans and institutions for dealing with major marine oilspills in the United States. Attempts to recover spilled oil, and to respond to the spill's environmental consequences, were hampered by a low level of preparedness and lack of clear agreement about the goals of response efforts. Attempts are under way to improve oil-spill prevention and response capabilities in Alaska and the rest of the United States. However, these efforts are not yet complete, and it remains to be seen whether an improved response will be made to the next major oil-spill.


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