Pollution risk from acid tanker is limited
Oil, not acid, will be the main pollution risk from the chemical tanker which went down in the English Channel this week.Although the Turkish-owned tanker was carrying 10,000 tonnes of phosphoric acid when it collided with another vessel on one of the world's busiest shipping lanes the impact of the acid is expected to be minimal.
As the acid is soluble in water and will be released slowly rather than all in one go, its effect will be limited.
To put it in perspective, the Channel contains an estimated 4 trillion cubic metres of water, so the relatively small quantity of acid would barely register on the radar and be quickly diluted.
Insoluble oils could pose more of a problem.
Dr Paul Johnston of the Greenpeace research laboratory in Exeter, outlined the severity of the situation.
"Depending on how much phosphoric acid is released, this chemical will hopefully be neutralised quickly, although some local environmental problems could result.
"An additional and longer term concern is the possible leakage of fuel and lubricating oils."
Official reports say the ship was carrying some 70 cubic metres of fuel oil, 5 cubic metres of diesel, one cubic metre of lubricant oil as well as containers of industrial cleaners and chemicals for ship maintenance.
Environmental pollution teams expect the oil to disperse or evaporate before landfall.
The ECE sank in 60m-70m of water, so is well submerged and does not pose a threat to other shipping.
"It's a wonder anyone is surprised this has happened," said Dr Johnston.
"When you have vessels travelling through the world's busiest shipping lane under flags of convenience carrying hazardous cargoes, accidents are inevitable.
"Many of these cargoes are only being transported to serve spot commodity markets. In many cases there's really no need for them to even be at sea."
"Unfortunately once a ship gets into difficulties containment of cargo and fuel oil can be extremely difficult and problematic."
Marine charity Oceana Europe has more concerns about the acid itself, saying it can be harmful to sea life even in small quantities as even slight changes in the pH levels of the water could have an impact.
As it is a phosphate, it can result in the eutrophication of aquatic media.
According to Oceana, however, it is a relatively weak acid and rarely causes long-term effects and the possibility of pollution at sea is limited to the area where the spillage has taken place and unlikely to have a serious environmental impact, although it may have a local effect.
Phosphoric acid is usually used in detergents and fertilisers and to flavour beer and soft drinks to give them a sharp, tart taste.
The Spanish-built tanker ECE was 18 years old and had no history of safety problems or faults.
"The accident of a vessel carrying hazardous materials is always a threat to the marine environment," said Xavier Pastor, director of Oceana.
"In this case, the cargo is not excessively harmful, but it adds more pollution to an area that is already the recipient of millions of tonnes of toxic spillages every year."
By Sam Bond
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