A killer whale who washed up on a Scottish beach last year was one of the “most contaminated” animals on the planet, researchers have found.
Lulu, one of the UK’s last killer whales, was founded dead on the Isle of Tiree after becoming entangled in fishing lines.
Tests carried out on the whale revealed she had incredibly high levels of polychlorinated biphenyls (PCBs) contamination.
PCBs, which were banned in the 1980s, were once widely used in electrical equipment as well as paint and plastics, and rubber products.
PCBs can cause cancer and suppress the immune system. They are very tough chemicals and do not break down in the environment.
Dr Andrew Brownlow, head of the Scottish Marine Animal Stranding Scheme and veterinary pathologist at Scotland’s Rural College (SRUC), told BBC News that Lulu had “shocking levels of PCBs”.
He said: “The levels of PCB contamination in Lulu were incredibly high, surprisingly so. They were 20 times higher than the safe level that we would expect for cetaceans to be able to manage.
“That puts her as one of the most contaminated animals on the planet in terms of PCB burden, and does raise serious questions for the long-term survivability of this group (of UK killer whales).”
The chemicals can affect the brain and experts believe the contamination could have contributed to Lulu’s death.
Dr Brownlow added: “It is potentially plausible that there was some effect of the PCBs that was in some way debilitating her so she wasn’t strong enough or even aware enough to deal with this entanglement (in fishing line).
A post-mortem showed that Lulu had never reproduced.
The World Wildlife Foundation (WWF) said PCBs can cause infertility, with these latest findings adding “to strong evidence that the pod is doomed to extinction”.
Simon Walmsley, WWF’s oceans manager, said: “The shockingly high levels of PCB contamination found in Lulu, the UK killer whale are another tragic example of the impact that we are having on nature.
“Such high levels of pollution in our oceans, rivers and atmosphere cannot be ignored.
“This requires action and it requires it fast. We must learn the lessons from these legacy pollutants and not release such contaminants into the environment without a clear understanding of the lasting impacts.
“In this case PCBs will stay in the environment and continue to pollute for many decades. We are on track to lose two-thirds of wildlife by 2020 and a large driver of this is the way we treat the planet.
“The results of this analysis must act as a reminder that it is imperative that we continue to strive to find a way that 7billion people can live on our planet without trashing it.”