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RECA: Contaminants

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Exxon Valez oil tanker aground on Bligh Reef, March 1989
Exxon Valez oil tanker aground on Bligh Reef, March 1989

Oil related contaminants in Alaska are often overlooked because of the widespread images of a pristine and boundless habitat. But, contaminants are often suspected to be a contributing cause to some unexplained changes in an ecosystem or a specific species population. The information base to support such hypotheses is usually sparse if they exist at all. This group of researchers, composed of biologists and chemists, developed extensive chemical and field experience with contaminants in the aftermath of the Exxon Valdez oil spill. As a consequence, our research continues with a small effort in contaminants, relying on outside funding, but also advises statewide on emerging oil related issues and planning.

Controversial Science: The Exxon Valdez oil spill in 1989 was a catastrophe that inadvertently created an un-planned “experiment” for long term study of the effects of an oil spill in a region where people and pollution had little prior environmental impact. As a result of the Exxon Valdez Oil Spill Trustee Council’s commitment to identifying damage, we found that part-per-billion concentrations of environmentally persistent polynuclear aromatic hydrocarbons (PAH) could cause immediate and delayed effects in fish embryos that translated to population injury that far outweighed the acute effects. This represented a significant change in our understanding of oil spill effects. Up until 1989 we expected that oil spills would affect fish populations through either ingestion of oil or acute naarcosis following exposure to volatile mon-aromatic compounds such as benzene, toluene, and xylenes in the part-per-thousand range. Our finding that lingering oil could cause population level injury for up to four years following the spill [1, 2] was hotly contested by ExxonMobil. Today, the controversy has been resolved although ExxonMobil scientists continue to publish reports questioning our orginal findings. Other laboratories from around the world have confirmed our findings using other species. Our original findings have now been reported to occur in demersal and pelagic eggs involving arctic, boreal and temperate species in both fresh and saltwater. At least eleven species have been show to experience teratogenic effects of weathered oil following exposure during early embryo development. The mechanism of injury has been described on a molecular level and directly linked to population level effects. Regulating agencies are now taking these effects for granted. All of this demonstrates that attempts to misuse the scientific process [3] to create doubt may delay our understanding of reality, but those efforts will ultimately whither under the weight of evidence supplied by more responsible parties.

One last controversy continues to present day, fueled by lingering oil in PWS and continuing litigation. As of May 2014, 25 years after the spill, a major litigation issue remains unsettled, and eight of the 21 injured species are still recovering. The stakes are high: the remaining litigation effort involves up to $100 million (between ExxonMobil and State/Federal governments. Currently, the State/Federal governments have petitioned Exxon for an additional $92 million, under the ‘reopener’ clause in the 1991 settlement. State/Federal governments are seeking these additional funds to restore current damage caused by lingering oil; this additional damage was unexpected at the time of the 1991 settlement.

An example of how the scientific process is misused to create doubt: In their paper, Brannon et al. 2006 [4] attempted to replicate some of the pink salmon embryo experiments done by our laboratory [5,6,7,8,9] using exposure methods similar to ours. Our series of papers present evidence that concentrations in the low part per billion PAH (5-20 ppb) can be very damaging to embryos and to populations of pink salmon and herring. The Brannon et al. paper is heavily critical of our series of papers, and cites toxic exposure doses in their study that were several orders of magnitude greater than our exposure concentrations. Simply put, what distinguishes the Brannon et al. (2006) report from ours is that they base their interpretations on dose added (nominal oiling) instead of dose measured (aqueous TPAH concentration).

We responded to the journal with a letter describing our differences. However, we were constrained by journal policy and could not respond in detail to all of the remarks in the Brannon paper in that forum. The following is a complete response to the Brannon et al. paper, covering some 60 points. In Part I, we include the letter submitted to the editors of Environmental Toxicology and Chemistry summarizing our disagreements. In Part II, we document in detail the disagreements with the Brannon et al. paper; these were too numerous to include in an efficient response to the Journal. Statements in the Brannon et al. paper are in typeset in black; our responses are in blue.

Download entire response (pdf): Response to Brannon et al. 2006

Key Publications in this Response

  1. Rice, S. D., R. E. Thomas, M.G. Carls, R.A. Heintz, A.C. Wertheimer, M.L. Murphy, J. W. Short, and A. Moles. (2001). "Impacts to pink salmon following the Exxon Valdez oil spill: persistence, toxicity, sensitivity, and controversy." Reviews in Fisheries Science 9: 165-211.

  2. Rice, S. D., J. W. Short, M.G. Carls, A. Moles, and R.B. Spies. (2006). The Exxon Valdez oil spill. Long-term ecological change in the northern Gulf of Alaska. R. B. Spies. Amsterdam, Elsevier: 413-514.

  3. Peterson, C. H., L. L. McDonald, R.H. Green, and W.P. Erickson. (2001). "Sampling design begets conclusions: the statistical basis for detection of injury to and recovery of shoreline communities after the 'Exxon Valdez' oil spill." Marine Ecology Progress Series 210: 255-283.

  4. Brannon, E. L., K. M. Collins, et al. (2006). "Toxicity of weathered Exxon Valdez crude oil to pink salmon embryos." Environmental Toxicology and Chemistry 25(4): 962-972.

  5. Carls, M. G., R. A. Heintz, et al. (2005). "Cytochrome P4501A induction in oil-exposed pink salmon Oncorhynchus gorbuscha embryos predicts reduced survival potential." Marine Ecology-Progress Series 301: 253-265.

  6. Carls, M. G., S. D. Rice, et al. (1999). "Sensitivity of fish embryos to weathered crude oil: Part I. Low-level exposure during incubation causes malformations, genetic damage, and mortality in larval Pacific herring (Clupea pallasi)." Environmental Toxicology and Chemistry 18(3): 481-493.

  7. Heintz, R. A., S. D. Rice, et al. (2000). "Delayed effects on growth and marine survival of pink salmon Oncorhynchus gorbuscha after exposure to crude oil during embryonic development." Marine Ecology-Progress Series 208: 205-216.

  8. Heintz, R. A., J. W. Short, et al. (1999). "Sensitivity of fish embryos to weathered crude oil: Part II. Increased mortality of pink salmon (Oncorhynchus gorbuscha) embryos incubating downstream from weathered Exxon Valdez crude oil." Environmental Toxicology and Chemistry 18(3): 494-503.

  9. Marty, G. D., J. W. Short, et al. (1997). "Ascites, premature emergence, increased gonadal cell apoptosis, and cytochrome P4501A induction in pink salmon larvae continuously exposed to oil-contaminated gravel during development." Canadian Journal of Zoology-Revue Canadienne De Zoologie 75(6): 989-1007.

Related Links:
EVOS Trustee Council
NMFS Office of Exxon Valdez Oil Spill Damage Assessment and Restoration
NOAA Office of Response and Restoration
Prince William Sound Oil Spill Recovery Institute
Prince William Sound Regional Citizens' Advisory Council
Cook Inlet Regional Citizens' Advisory Council

Ron Heintz
Auke Bay Laboratories
Alaska Fisheries Science Center, NOAA Fisheries

Ted Stevens Marine Research Institute
17109 Pt Lena Loop Rd
Juneau AK 99801
(907) 789-6058

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