| Summary: | Oil/Gas extraction have left Louisiana with a legacy of abandoned infrastructure across the State. Presently, the State has developed guidelines for the removal of abandoned vessels and abandoned on shore facilities. No such guidelines exist, however, for the network of abandoned pipelines present throughout the coastal zone of Louisiana.
A pipeline removal was simulated in Lake Calcasieu, LA. The site was chosen because of the presence of many abandoned pipelines and previous work done on sight to remove the on shore infrastructure. In addition, the Calcasieu is an industrial water body, with potentially hazardous pollutants sequestered in the sediments of the lake bottom. Several industrial facilities discharge effluents into the water body, and a superfund site exists as a result. The sediment plume created during the perturbation event was monitored with triploid and diploid oysters to assess the toxicological consequences of the sediment plume.
Oyster tissue was analyzed for alkanes, Polynuclear Aromatic Hydrocarbons, hexachlorabutadiene, trace metals and organo metals. No difference was seen among concentrations of analytes between diploid and triploid oysters. In addition, the condition index of diploid oysters matched those of the triploid oysters, suggest spawning did not occur during the field study.
Test Cage 3 oysters were most affected by the perturbation event and displayed significant (p < .05) increases in total hydrocarbon concentration and in 13 of 16 metals tested. These increases corresponding with significant (p < .05) drop in the condition of Test cage 3 oysters 3 days following perturbation, from 6.6 to 4.8. No other Test Cage oysters displayed a clear response in body concentrations to the perturbation event. As such, the northern and southern range of the sediment plume can be demonstrated though analysis of the oyster tissue. Such data would be of critical importance in determining any deleterious affects to the aquatic ecosystem attributable to the sediment plume as a result of pipeline removal.
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