Lasting Menace
Gulf oil-spill disaster likely to exert environmental harm for decades
By David Biello
Scientific American
More than 20 years after the Exxon Valdez foundered off the coast of Alaska, sea otters still dig up oil in their hunt for clams in Prince William Sound. Nearly 25 years after an oil storage tank ruptured near mangrove swamps and coral reefs of Bahia Las Minas in Panama, oil slicks still form in the water. And some 40 years after the fuel-oil barge Florida ran aground off Cape Cod, the muck beneath the marsh grasses makes the area smell like a gas station.
Similar damage may be in store for the U.S. Gulf coast, given that millions of gallons of light sweet crude spewed from BP’s broken well 1,500 meters down and approximately 65 kilometers off the Louisiana coast. Its oil-drilling rig Deepwater Horizon exploded on April 20, and efforts to cap the flow—estimated to be 200,000 to a few million gallons a day during the weeks right after the accident—suffered setbacks and delays. All the oil released, which could ultimately exceed the Valdez spill several times over, could compromise wildlife and local livelihoods for years.
The toxic compounds in oil vary, but the most worrisome are polycyclic aromatic hydrocarbons (PAHs), such as napthalenes, benzene, toluene and xylenes. All can sicken humans, animals and plants. “These hydrocarbons are particularly relevant if inhaled or ingested,” says environmental toxicologist Ronald J. Kendall of Texas Tech University. “In the bodies of organisms such as mammals or birds, these aromatic hydrocarbons can be transformed into even more toxic products, which can affect DNA.” The mutations that might result could lead to reduced fertility, cancer and other problems.
Not all the PAHs become an environmental threat, though. Thanks to evaporation, oil that reaches the surface loses at least 20 to 40 percent of the original hydrocarbons. “Evaporation is good; it selectively removes a lot of compounds we’d rather not have in the water,” says marine chemist Christopher M. Reddy of the Woods Hole Oceanographic Institution. The oil also emulsifies, forming mousse—a frothy mix of hydrocarbons and water—or clumps into so-called tar balls.
(More here.)
By David Biello
Scientific American
More than 20 years after the Exxon Valdez foundered off the coast of Alaska, sea otters still dig up oil in their hunt for clams in Prince William Sound. Nearly 25 years after an oil storage tank ruptured near mangrove swamps and coral reefs of Bahia Las Minas in Panama, oil slicks still form in the water. And some 40 years after the fuel-oil barge Florida ran aground off Cape Cod, the muck beneath the marsh grasses makes the area smell like a gas station.
Similar damage may be in store for the U.S. Gulf coast, given that millions of gallons of light sweet crude spewed from BP’s broken well 1,500 meters down and approximately 65 kilometers off the Louisiana coast. Its oil-drilling rig Deepwater Horizon exploded on April 20, and efforts to cap the flow—estimated to be 200,000 to a few million gallons a day during the weeks right after the accident—suffered setbacks and delays. All the oil released, which could ultimately exceed the Valdez spill several times over, could compromise wildlife and local livelihoods for years.
The toxic compounds in oil vary, but the most worrisome are polycyclic aromatic hydrocarbons (PAHs), such as napthalenes, benzene, toluene and xylenes. All can sicken humans, animals and plants. “These hydrocarbons are particularly relevant if inhaled or ingested,” says environmental toxicologist Ronald J. Kendall of Texas Tech University. “In the bodies of organisms such as mammals or birds, these aromatic hydrocarbons can be transformed into even more toxic products, which can affect DNA.” The mutations that might result could lead to reduced fertility, cancer and other problems.
Not all the PAHs become an environmental threat, though. Thanks to evaporation, oil that reaches the surface loses at least 20 to 40 percent of the original hydrocarbons. “Evaporation is good; it selectively removes a lot of compounds we’d rather not have in the water,” says marine chemist Christopher M. Reddy of the Woods Hole Oceanographic Institution. The oil also emulsifies, forming mousse—a frothy mix of hydrocarbons and water—or clumps into so-called tar balls.
(More here.)
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