Major new research shows that half of the world’s orca populations are likely to be wiped out by PCBs
Although they were banned in the 1980’s PCBs (polychlorinated biphenyls – a persistent organic chemical) are still causing an astonishing level of toxic pollution in our seas. It is estimated that around 14 million tonnes of PCB containing materials, including sealants, paints and electrical materials have still not been disposed of safely under the Stockholm Convention. As a predator at the top of the food chain, killer whales are especially vulnerable to pollution from the toxic chemical as it accumulates up the food chain. The toxins are stored in their blubber layer and travel around their body causing reduced immune function, damaging reproductive organs and leading to cancer. Female killer whales will even offload the toxins into their new born through the rich fatty milk she produces using her fat stores.
Populations are particularly threated in industrialised areas such as Brazil, the Strait of Gibraltar and around the UK. The last remaining resident pod of killer whales in the UK is most at risk and haven’t bred in over 25 years. In 2016 the death of a female, known as Lulu, from the pod showed the highest level of the toxin ever recorded in an animal.
This new research, published in the journal Science, was the largest analysis yet and examined PCB contaminations in 351 killer whales. Scientists used this research along with previous data on how PCBs can affect calf survival and immune systems to model the state of populations in the future. They concluded that ‘populations of Japan, Brazil, Northeast Pacific, Strait of Gibraltar and the UK are all tending toward complete collapse’.
ORCA Head of Science and Conservation said ‘These new figures show the devastation invisible chemical pollution is having on orcas. At the top of the food chain PCBs build up in their organs slashing the whales’ ability to survive and reproduce. With a shocking 50% of orcas set to be wiped out by PCBs alone, our abysmal failures to control chemical pollution ending up in our oceans has caused a killer whale catastrophe on an epic scale. It is essential that requirements to dispose safely of PCBs under the Stockholm Convention are made legally-binding at the next meeting in May 2019 to help stop this scandal.’
In 2004 The Stockholm Convention was put in place and is a global framework for the use of PCBs, however it lacked controls to prevent future PCB pollution.
Currently there is nothing in place to ensure all remaining PCBs are disposed of safely by the target date of 2028, resulting in remaining stocks slowly leaking into and contaminating our water sources.
A group of wildlife charities, including ORCA and co-ordinated by Wildlife and Countryside Link are calling for all countries attending the Stockholm Convention in May 2019 to commit to legally binding targets and establishing an operational compliance and enforcement mechanism. The NGO’s are urging the UK Government to lead the way by including binding targets on PCBs in the upcoming Environment Act.
Photo credit: Elfyn Pugh