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Oil well leaks foul fish flesh

rigged.JPGThe Deepwater Horizon disaster has focused many minds on the problem of oil wells going wrong. But even wells that operate perfectly leak oil into the environment. A new study shows that this has a major effect on local ecosystems, one that is only going to get worse in future.

Tomas Hansson, of Stockholm University, and his colleagues analysed biomarkers in fish populations in areas of the North Sea with heavy oil production. They were looking for signals of exposure to polycyclic aromatic hydrocarbons in haddock and cod; and they found it.

“It is very surprising to find health effects in natural fish populations in the open sea that are similar to the health effects in fish from highly polluted areas close to specific point sources along the coast,” Hansson said in an email to Nature.

Polycyclic aromatic hydrocarbons (PAHs) can leach into the ocean from oil industry processes, for example from seawater pumped into oil reservoirs to maintain pressure and from water already present in the reservoir. A 2003 National Academies report highlights that around 38,000 tonnes of hydrocarbons a year are estimated to enter the oceans via such ‘produced water’, with 8,200 tonnes ending up in the North Sea.


Hansson’s team found that both haddock and cod were exposed to PAHs and that there were biological effects from this, such as alterations in fatty acid make-up in the fish and genotoxicity, they report in PLoS One. There was also a general relationship between the biomarkers they looked at – such as alterations in fatty acid composition in fish – and the intensity of oil production.

“Considering that the offshore oil production has been going on continuously for several decades, it is also worrying that the accumulated knowledge about its chronic health effects on natural fish populations is still very limited,” says Hansson. “Offshore oil production is obviously harmful to the fish, and may thus be a threat to the sustainability of the fish stocks, just as overfishing, climate change, and eutrophication are.”

In addition to the threat to the animals themselves, there may be knock on effects for those eating them. The concentrations of hydrocarbons found in the bile of fish don’t suggest that eating the animals could do any direct harm, but they might lower the quality of the fish, by reducing concentrations of omega 3 fatty acids and vitamin E.

Worryingly, pollution from ‘produced water’ increases as oil reservoirs become depleted and more water must be pumped into them to maintain pressure. As North Sea reserves run down, pollution from wells is going to get worse even without a Deepwater-style accident.

Image: stock photo / Punchstock

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    jirsay said:

    I’d like to find out more about any health consequences from eating fish that that have been “altered” by oil.

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