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fork(2) [soylentnews.org] writes:

      The Deepwater Horizon oil spill dumped nearly 3 million barrels of crude oil into the northern Gulf of Mexico in 2010. Six years is a long time, and the disaster has slipped from the minds of many in that time. (Aided, no doubt by the kind of "There's Nothing To See Here" headlines that Treehugger [treehugger.com] captured here.)

      But, still, in the real world the legacy continues.

      On Monday (July 11) ScienceDaily [sciencedaily.com] reported on research looking at some of the effects of "weathered oil":

[...] A research team led by an environmental scientist at the University of California, Riverside has now found that ultraviolet light is changing the structure of the DWH oil components into something more toxic, further threatening numerous commercially and ecologically important fishes.

      "Ours is the first experiment evaluating the effects of DWH oil on the genetic responses of Mahi embryos and larvae," said Daniel Schlenk, a professor of aquatic ecotoxicology, who led the study published in Environmental Science and Technology. "It is also the first experiment of this nature on a lifestage and species that was likely exposed to the oil. We found that the weathering of oil had more significant changes in gene expression related to critical functions in the embryos and larvae than the un-weathered oil. Our results predict that there are multiple targets of oil for toxicity to this species at the embryonic life stage."

      "We found that the heart, eye and neurological function were affected," Schlenk said. "In collaboration with other consortia members from the Universities of Miami, Texas, and North Texas, we are now following up with these results. Previous studies have shown that the heart is the primary target for oil. Our study shows that in addition to heart function, risk and recovery should also examine eye and neuronal function."

      It is important to understand how contaminants cause toxicity in order to increase certainty in risk assessment.

"By understanding how fossil fuels cause toxicity we can have a better understanding of the risks associated with these contaminants and determine regulatory or management strategies that reduce risks of these substances," he said. "To this day, we remain uncertain of the magnitude of the DWH oil spill effects, particularly in sensitive life stages of fish. We are also uncertain of whether biota exposed to the oil can recover, or have recovered, from this event. And we are still uncertain about how compounds present in oil or any other combustion byproduct or fossil fuel cause toxicity."

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