While the report conclusions show hydrocarbons accumulate to the greatest degree in shrimp eggs, the overall takeaway message from the study is hydrocarbon tainting of shrimp muscle (the part usually consumed) is well below that which is considered to pose a human health risk. Researchers, however, suggested further study to determine whether the hydrocarbon levels detected in the eggs have an effect on the shrimp’s development.
Document Author: Larry Holland
Embryonic Crude Oil Exposure Causes Cardiac Hypertrophy And Reduced Aerobic Performance In Juvenile Pink Salmon And Pacific Herring
Studies subsequent to the spill identified disruption of heart morphogenesis as a major impact of polycyclic aromatic hydrocarbons (PAHs) derived from crude oil. Here we show that pink salmon and herring embryos exposed transiently to trace levels of Alaskan crude oil develop cardiac abnormalities that lead to permanent changes in heart anatomy and physiological performance. When assessed after 7 to 10 months of growth in clean water, both species showed reduced aerobic capacity and common changes in cardiac morphology, including evidence of ventricular hypertrophy. Therefore, the Exxon Valdez oil spill likely impacted pink salmon and herring more than previously appreciated. Moreover, the particular sensitivity of herring embryos to PAHs suggest that the catastrophic collapse of the Prince William Sound population may have been caused in part by delayed mortality due to developmental cardiotoxicity. These findings extend our understanding of the long-term impacts of oil spills, and apply also to more chronic inputs of PAH pollution to aquatic systems from land-based runoff and other sources.
The Effectiveness of Corexit 9527 and 9500 in Dispersing Fresh, Weathered, and Emulsion of Alaska North Slope Crude under Subarctic Conditions
A modified version of the swirling flask effectiveness test was conducted at temperatures of 3, 10 and 22C with salinities of 22% and 32%. Petroleum dispersed into the water column following application of dispersant was measured by gas chromatography with FID detection. Results showed dispersants dispersed less than 40% of the fresh oil, none of the weathered oil, and were most effective when used to disperse a stable oil/water emulsion at 10C. At the combinations of temperature and salinity most common in the estuaries and marine waters of Alaska, the dispersants were largely ineffective (<10% effective, the detection limit of the tests) at dispersing fresh or weathered Alaska North Slope crude oil in laboratory tests.