Environmental impact
The oil spill, which began on January 23, 1991, caused considerable damage to wildlife in the Persian Gulf especially in areas surrounding Kuwait and Iraq.[2] Estimates on the volume spilled usually range around 11 million barrels (462 million gallons or 1.75 billion liters);[3] the slick reached a maximum size of 101 by 42 miles (4242 square miles or 10860 km²) and was 5 inches (13 cm) thick in some areas. Despite the uncertainty surrounding the size of the spill, figures place it several times [4] the size (in gallons spilled) of the Exxon Valdez oil spill, and almost twice the size of the 1979 Ixtoc I blowout in the Gulf of Mexico.
The New York Times reported that a 1993 study sponsored by UNESCO, Bahrain, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, the United Arab Emirates and the United States found the spill did "little long-term damage": About half the oil evaporated, a million barrels were recovered and 2 million to 3 million barrels washed ashore, mainly in Saudi Arabia.[5]
More recent scientific studies strongly disagree with this [optimistic] 1993 assessment. Marshlands and mud tidal flats continued to contain large quan ies of oil, over ten years later, and full recovery is likely to take decades.
Dr. Jacqueline Michel, US geochemist (2010 interview – transcript of radio broadcast):[6]
The long term effects were very significant. There was no shoreline cleanup, essentially, over the 800 kilometers that the oil – - in Saudi Arabia. And so when we went back in to do quan ative survey in 2002 and 2003, there was a million cubic meters of oil sediment remained then 12 years after the spill.... [T]he oil penetrated much more deeply into the intertidal sediment than normal because those sediments there have a lot of crab burrows, and the oil penetrated deep, sometimes 30, 40 centimeters, you know a couple of feet, into the mud of these tidal flats. There’s no way to get it out now. So it has had long term impact.
Dr. Hans-Jörg Barth, German geographer (2001 research report):[7]
The study demonstrated that, in contrary to previously published reports e.g. already 1993 by UNEP, several coastal areas even in 2001 still show significant oil impact and in some places no recovery at all. The salt marshes which occur at almost 50% of the coastline show the heaviest impact compared to the other ecosystem types after 10 years. Completely recovered are the rocky shores and mangroves. Sand beaches are on the best way to complete recovery.
The main reason for the delayed recovery of the salt marshes is the absence of physical energy (wave action) and the mostly anaerobic milieu of the oiled substrates. The latter is mostly caused by cyanobacteria which forms impermeable mats. In other cases tar crusts are responsible. The availability of oxygen is the most important criteria for oil degradation. Where oil degrades it was obvious that benthic intertidal fauna such as crabs re-colonise the destroyed habitats long before the halophytes. The most important paths of regeneration are the tidal channels and the adjacent areas. Full recovery of the salt marshes will certainly need some more decades.