Killer whales have become the most contaminated mammals in the Arctic, new research indicates.
Killer whales suffer because they are at the top of the food chain
Norwegian scientists have found that killer whales - or orcas, as they are sometimes known - have overtaken polar bears at the head of the toxic table.
No other arctic mammals have ingested such a high concentration of hazardous man-made chemicals.
The Norwegian Polar Institute tested blubber samples taken from creatures in Tysfjord in the Norwegian Arctic.
The chemicals they found included pesticides, flame retardants and PCBs - which used to be used in many industrial processes.
Animals at the top of the food chain are particularly affected, and whales - like polar bears - can reflect the health of the marine environment.
The researchers are particularly worried about the flame retardants, because unlike many other harmful chemicals, some are still legal.
The international environmental group, WWF, says the Arctic has become a chemical sink.
It says the findings dramatically underline the need for European Union ministers to decide on strong legislation when they meet this week.
However, WWF says it fears pressure from the chemicals industry could lead to any new laws being so watered down that they will protect neither the environment nor human health.