Estimate of Oil Persisting on the Beaches of Prince William Sound 12 Years after the Exxon Valdez Oil Spill

Abstract

We estimated the amount of oil remaining in Prince William Sound, Alaska, 12 yr after the 1989 Exxon Valdez spill to assess its importance as a long-term reservoir of toxic hydrocarbons. We found oil on 78 of 91 beaches randomly selected according to their oiling history. Surface oiling was recorded for randomly placed quadrats, which were then excavated and examined for subsurface oil. The cumulative area of beach contaminated by surface or subsurface oil was estimated at 11.3 ha. Surface oil varied little with tide height, but subsurface oil was more prevalent at the middle tide heights. The mass of remaining subsurface oil is conservatively estimated at 55 600 kg. Analysis of terpanes indicated that over 90% of the surface oil and all of the subsurface oil was from the Exxon Valdez and that Monterey Formation oil deposited after the 1964 Alaska earthquake accounted for the remaining surface oil. These results indicate that oil from the Exxon Valdez remains by far the largest reservoir of biologically available polycyclic aromatic hydrocarbons on beaches impacted by the spill and that biota dependent on these beaches risk continued exposure.

Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill

“…The authors of these studies concluded that oil remaining in the environment, particularly in intertidal areas, was encountered and ingested by some near-shore verte- brates. This conclusion is consistent with confirmation of the occurrence of residual Exxon Valdez oil in intertidal sediments of Prince William Sound during the same period in which elevated CYP1A was indicated [15] as well as calculations that intertidal-foraging vertebrates would be likely to encounter lingering oil repeatedly through the course of a year [16].…”

“…Parameter likelihoods (P.L. ), weighted parameter estimates, and unconditional standard errors (SE) derived from information-theoretic analyses using general linear models to evaluate variation in hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity (pmol/min/mg protein) of harlequin ducks captured in where elevated CYP1A was observed in vertebrates are predominantly from the Exxon Valdez spill [15], supporting the inference that Exxon Valdez oil was the inducing agent. Recent studies have indicated that sites with residual Exxon Valdez oil had bioavailable PAHs that elicited CYP1A induction when experimentally injected into fish [34].…”

Cytochrome P4501A biomarker indication of the timeline of chronic exposure of Barrow’s goldeneyes to residual Exxon Valdez oil

“…However, studies indicate that PAHs in the areas where elevated CYP1A was observed in vertebrates are predominately from the Exxon Valdez (Short et al, 2004), supporting the inference that Exxon Valdez oil was the inducing agent. Also, other studies (Trust et al, 2000;Ricca et al, 2010) a Cohort consists of an age class designation (HY = hatch-year, i.e., within one year of hatching; AHY = after-hatch-year) and sex (M = male; F = female).…”

“…Some of the oil released during the 1989 Exxon Valdez oil spill has remained in intertidal sediments of Prince William Sound, Alaska over the subsequent two decades (Boehm et al, 2008;Short et al, 2004;Short et al, 2006). Estimates of the quantity remaining (Boehm et al, 2008;Short et al, 2004) represent a small fraction of the oil that originally settled on Prince William Sound beaches following the spill (Wolfe et al, 1994), with residual oil in intertidal areas estimated to exceed 50,000 kg in 2001 (Short et al, 2004).…”

“…Estimates of the quantity remaining (Boehm et al, 2008;Short et al, 2004) represent a small fraction of the oil that originally settled on Prince William Sound beaches following the spill (Wolfe et al, 1994), with residual oil in intertidal areas estimated to exceed 50,000 kg in 2001 (Short et al, 2004). Concern and debate persist over whether vertebrates continue to be exposed to the remaining oil and, if so, whether that exposure negatively affects individuals or populations.…”