Tuesday, July 6, 2010

Ocean pollution caused by oil spills and arsenic

Oil spills are creating different forms of ocean pollution, and the latest study published in the journal Water Research has even revealed that oil spills can also increase levels of toxic arsenic in the ocean, creating an additional long-term threat to many marine ecosystems.

Arsenic is poisonous material that is found in oil, and high levels of arsenic in seawater can enable the toxin to enter the food chain where it can create huge damage to many marine organisms. The negative effects of arsenic in seawater include disruption of photosynthesis process in marine plants, different genetic alterations that can cause birth defects, and it can also kill animals such as birds that feed on sea creatures affected by arsenic.

Though arsenic occurs naturally in the oceans, sediments on the sea floor filter it out of seawater, which keeps the levels of naturally occurring arsenic low. Oil spills can somewhat block the ocean's natural filtration system and prevent this from cleaning arsenic out of the seawater, which would significantly increase the levels of arsenic in seawater.

The researchers from the Imperial College London have discovered that oil spills and leakages clog up sediments on the ocean floor with oil, which prevents the sediments from bonding with arsenic and burying it safely underground with subsequent layers of sediment. The scientists also explained that this shutdown of the natural filtration system causes arsenic levels in seawater to rise. Increased levels of arsenic in seawater means that arsenic can enter the marine ecosystems, where it becomes more concentrated and poisonous the further it moves up the food chain.

To connect this with the current oil spill in the Gulf of Mexico the scientists said how they "can't accurately measure how much arsenic is in the Gulf at the moment because the spill is ongoing". However, they have warned that the real danger lies in arsenic's ability to concentrate and accumulate, which means that each subsequent spill raises the levels of this pollutant in seawater.

Since thousands of gallons of oil are leaked into our oceans each year from not only big oil spills but also from offshore drilling and routine maintenance of rigs, many places may be at risk from increased arsenic levels, which could in the long run affect entire marine life, and also the people who rely on the oceans for their livelihoods.

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