Norwegian killer whales are the most toxic mammals in the Arctic, according to a new study.
The Norwegian Polar Institute (NPI) has found that killer whales have higher levels of chemicals known as PCBs, pesticides and flame retardants in their blubber.
Previously the polar bear had taken the title of most toxic animal in the research funded by international environmental group WWF.
"This new killer whale research re-confirms that the Arctic is now a toxic sink," said Brettania Walker, a toxics officer with WWF's international arctic programme.
NPI researcher Dr Hans Wolkers said: "Killer whales can be regarded as indicators of the health of our marine environment.
"The high levels of contaminants are very alarming. They clearly show that the arctic seas are not as clean as they should be, which, in particular, affects animals at the top of the food chain."
The flame retardants are used in electronic goods and coatings for household products such as carpets but can affect whales' neurological functions, behaviour and reproduction.
WWF and the Norwegian government are now pushing for EU leaders to ban the chemicals when the European Council of Ministers votes on Reach (Registration, Evaluation and Authorisation of Chemicals) tomorrow.
Helen Bjornoy, the Norwegian minister of environment, said: "This is one of the greatest global environmental threats.
"The EU ministers now have the possibility to strengthen the chemicals legislation in Europe, and I urge them to use it. It is imperative that the Reach regulation becomes a tool to stop using the most dangerous chemicals."