August 11, 2014
Scientists Use Controlled Oil Spill To Analyze The Immediate Result Of Such Disasters
redOrbit Staff & Wire Reports - Your Universe Online
When an oil spill occurs, it usually takes scientists and clean-up crews several days to arrive on the scene, making it unclear exactly what happens to the petroleum-based product during the first 24 hours after it hits the water.In a new study, however, corresponding author Samuel Arey of the Ecole Polytechnique Fédérale de Lausanne (EPFL) and the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and his colleagues set out to close that knowledge gap by conducting a controlled spill in the North Sea. They claim the findings of their field experiment could help change emergency responses in the immediate aftermath of such disasters.
According to Kukil Bora of International Business Times, the researchers discovered that once the oil is spilled onto the surface of a body of water, some of it instantly begins to evaporate into the air while some of it starts dissolving into the seawater. The dissolved toxic hydrocarbons can be harmful to marine species, while the evaporated elements are a potential cause for concern among on-site rescue workers and those living downwind of an accident location.
Arey and an international team of experts from the Helmholtz Centre for Environmental Research – UFZ, the Royal Netherlands Institute for Sea Research (NIOZ), the University of Amsterdam’s Institute for Biodiversity and Ecosystem Dynamics, Woods Hole Oceanographic Institution (WHOI) and elsewhere, published their findings Friday in the journal Environmental Science & Technology.
They said their paper was “the first report on the broad-spectrum compositional changes in oil during the first day of a spill at the sea surface,” and explained that they analyzed the composition of the oil slick shortly after allowing 4.3 cubic meters of oil to be released into the North Sea. They reported witnessing “rapid mass transfers of volatile and soluble hydrocarbons,” with more than half of the C17 hydrocarbons disappearing within 25 hours.
“In its new environment, the oil immediately begins to change its composition, and much of that change happens on the first day,” Arey explained in a statement. While some of the compounds evaporate in hours contaminating the atmosphere, others (such as toxic naphthalene) simultaneously dissolve into the seawater, posing a threat to aquatic life, he added.
In the wake of oil spills such as the 1990 Exxon Valdez disaster and the more recent Deepwater Horizon oil spill, scientists have been working to determine the extent to which marine species living in the area of a petroleum spill are exposed to toxic hydrocarbons, the researchers said. However, since many of those hydrocarbons are usually dispersed into either the air or water before scientists arrive on the scene, the question has been difficult to answer.
The researchers, in collaboration with Dutch emergency response specialists, recreated a four cubic meter oil spill in an area of the North Sea that had already been exposed to pollution, approximately 200 km off the coast of the Netherlands. They said that by analyzing the behavior of this relatively small amount of oil, they were able to gain a much better idea of the risks that larger disasters pose to both marine life and emergency response team workers.
However, as the EPFL noted, “no two oil spills are alike. Aside from the sheer volume of oil released onto the sea surface, the environmental impact of an oil spill depends on external factors, such as the wind, waves, and the temperature of the air and the water. The North Sea experiment, for instance, was carried out on a summer day with two-meter high waves. Within just over a day, the surface oil slick had almost dissipated. On a cooler day with less wind and smaller waves, the slick would have likely persisted longer.”
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