Exxon's Valdez studies ignite controversy.Alaska's Prince William Sound Prince William Sound, large, irregular, islanded inlet of the Gulf of Alaska, S Alaska, E of the Kenai peninsula. It has many bays and good harbors; the large Columbia Glacier flows into Columbia Bay, in the N central portion. "has almost fully recovered from the 1989 Exxon Valdez oil spill The Exxon Valdez Oil Spill is considered one of the most devastating man-made environmental disasters ever to occur at sea. Prince William Sound's remote location (accessible only by helicopter and boat) made government and industry response efforts difficult and severely taxed :' assert officials with the Houston-based Exxon Co. USA. That assessment, based on a spate of new papers by company-funded researchers, provoked an immediate flurry of heated charges and countercharges last week.
Exxon scientists say their data indicate that widespread oil contamination has plagued Prince William Sound for more than a century. They interpret these findings to suggest that area aquatic life can coexist with low levels of oil - and even recover from occasional heavy oiling.
Government claims of long-term Exxon Valdez This article is about the tank vessel Exxon Valdez. For the spill, see Exxon Valdez oil spill.
Exxon Valdez was the original name (later Sea River Mediterranean and eventually Mediterranean damage usually can be traced to a "faulty interpretation" of data, Exxon argues in a statement it released April 26. As a result, the company says, government scientists have mistakenly assumed "that large numbers of biologic and sediment samples from Prince William Sound contained remnants of Exxon Valdez crude when, in fact, they did not."
Exxon issued its statement at the opening of a four-day environmental session at an American Society for Testing and Materials (ASTM ASTM
American Society for Testing and Materials ) meeting in Atlanta. Researchers funded by Exxon presented 25 papers there on the Valdez spill.
However, some of those same papers lead chemist Jeffrey W.. Short of the National Marine Fisheries Service The U.S. National Marine Fisheries Service (NMFS) is a United States federal agency. A division of the National Oceanic and Atmospheric Administration (NOAA) and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine in Juneau, Alaska “Juneau” redirects here. For other uses, see Juneau (disambiguation).
The City and Borough of Juneau (pronounced [ˈdʒu. , to suspect that there is at least some possibility that Exxon is ascribing to other sources a portion of the oil that actually came from the Valdez spill.
His concerns involve studies that attempted to identify the source of an oil from the chemical fingerprints of its polycyclic aromatic hydrocarbons (PAHs). These PAHs offer a relatively stable oil signature - one that persists even after a sample has weathered, or begun to turn tarry tarry /tar·ry/ (tahr´e)
1. filled with or covered by tar.
2. thick, dark; resembling tar.
said of feces that are black and glutinous. See also melena. .
In one study, chemist David S. Page of Bowdoin College Bowdoin College, at Brunswick, Maine; coeducational; chartered 1794, opened 1802, named for James Bowdoin. One of the nation's older colleges, its alumni include Nathaniel Hawthorne, Henry Wadsworth Longfellow, and Franklin Pierce. in Brunswick, Maine, and his co-workers assayed PAHs in more than 2,350 seafloor sediments collected in Prince William Sound and the adjacent Gulf of Alaska Noun 1. Gulf of Alaska - a gulf of the Pacific Ocean between the Alaska Peninsula and the Alexander Archipelago
Pacific, Pacific Ocean - the largest ocean in the world between 1989 and 1991.
Coauthor A. Edward Bence, a geochemist with Exxon in Houston, recalls how surprised he was to find a consistent background signature of crude oil -- one quite different from the Valdez oil -- going back at least 160 years throughout the supposedly pristine sediments in Prince William Sound. The age of the signature argued for some natural, continuing source of this petroleum.
Realizing that crude-oil seeps had been charted in several places along the eastern Gulf of Alaska, the researchers compared fingerprints of oil from the seeps to those of oil in Prince William Sound sediments. They matched.
Other Exxon studies offered an explanation of how the seeps' oil might have entered Prince William Sound. Clays from glaciers to the east readily combine with oil -- especially weathered oil -- to form flocculated emulsions (see story, p. 302). These buoyant floc floc
A flocculent mass formed in a fluid through precipitation or aggregation of suspended particles.
[Short for flocculus.]
Noun 1. particles would ride west on the Alaska coastal current (see diagram on facing page) until they hit the sound's slow waters and settled.
The Exxon survey of sediment fingerprints revealed large amounts of petroleum PAHs- concentrations sometimes approaching 500 to 1,000 parts per billion. In deep areas, most of the oil appears to have come from seeps. In shallower zones, diesel fuel was often present. And because this diesel oil, perhaps spilled during refueling, bore a signature quite similar to that of the Exxon Valdez oil, government chemists often mistook the two, Bence contends.
That's definitely possible and reflects "the bias I entered with," concedes Short, who led some of those analyses. ff an oil fingerprint bore the distinctive PAH PAH, PAHA aminohippuric acid.
PAH 1 Polycyclic aromatic hydrocarbon, see there 2. Pulmonary artery HTN peaks representing phenanthrenes and dibenzothiophenes - characteristic of North Slope crude oil --"I assumed it was Exxon Valdez oil:' he says. In fact, North Slope diesel oil contains the same two PAH peaks. Exxon differentiated between the two oil types by looking for Looking for
In the context of general equities, this describing a buy interest in which a dealer is asked to offer stock, often involving a capital commitment. Antithesis of in touch with. chrysenes: The diesel lacks these PAHs.
Short's own PAH fingerprinting supports Exxon's finding of background contamination with nonNorth Slope crude oil in deep Prince William Sound sediments those in 40 to 100 meters of water. But his studies indicate that shallow, intertidal in·ter·tid·al
Of or being the region between the high tide mark and the low tide mark.
in sediments generally remained pristine - totally free of petroleum residues - unless or until oiled by the Exxon Valdez spill.
And that's why at least one paper at the ASTM meeting bothered him. It attributed most o! the PAHs in biological materials from one tidal area to a mix of seep oil and North Slope diesel. If one assumes such shallow areas contain a mix of diesel, seep, and ValdezoiI, he says, then one can attribute much of any phenanthrenes and chrysenes present to seep oil, and much of the dibenzothiophene signature to diesel. This would allow you "to cover most of what you see with non-Exxon-Valdez oil -- even if Valdez crude is the only [oil] present:' he says. That prospect, he adds, "makes me suspicious."
Many government scientists lauded Exxon for the science reported at the ASTM meeting. Like Short, however, many also questioned how data from that research were being interpreted.
For instance, Exxon claims that "[oil] spill effects were not significant to the herring." But Evelyn D. Biggs with Alaska's Department of Fish and Game in Cordova Cordova, Spain: see Córdoba. says even Exxon's data don't support that claim. Her own histopathology his·to·pa·thol·o·gy
The science concerned with the cytologic and histologic structure of abnormal or diseased tissue.
The study of diseased tissues at a minute (microscopic) level. studies show that "the tissues of fish in the oiled areas are more screwed up than tissues from fish in unoiled,' she says.
Dennis Heinemann, a Camarillo, Calif.based consulting seabird biologist, objects to the way Exxon's "careful:' but limited, study on murres -- a diving seabird -- ignores conflicting findings from bigger, longer observations of those same birds (SN: 2/13/93, p. 102). He compared Exxon's efforts to "looking at one tree" and then generalizing that conclusions drawn from it could "represent the whole forest." -J. Raloff