Exxon Valdez: Oil still pollutes the environment
17 years after the US tanker Exxon Valdez sank off the coast of Alaska, oil spills continue to plague the region's ecosystems.
The creeping release of pollutants and their accumulation in the food chain could therefore be the reason why the stocks of ducks and sea otters in the vicinity of the accident site - Prince William Sound - have recovered much less since 1989 than in less heavily contaminated areas. According to the studies by Jeff Short of the Alaska National Sea Fishery Service and his colleagues, the residues are not only found under very high coastal sections, but also in lower tidal zones where the animals regularly search for food.
In total, the researchers discovered heavy oil on the surface and in the subsoil of sand and silt on 14 of 32 beaches examined. Since otters, like ducks, frequently churn up the ground to get at mussels or worms while foraging, they could very often come into contact with or ingest the oil. This is also supported by the high concentrations of detoxification enzymes in the bodies of the animals that live in Prince William Bay.
Short's team estimates that nearly twenty years after the ship sank, more than 100,000 liters of the original 40 million liters of crude oil that spilled are still spilling on the Sound's shores. Since the lower-lying tidal zones are not exposed to wind and weather for at least half of the day, the affected beaches could continue to be affected for decades, say the scientists.
