Recent years have witnessed the resurgence in whale populations across the globe after whaling was largely outlawed. Unfortunately this same resurgence is not being witnessed in European waters as a lingering evil is still polluting the water with the potential to cause extinctions in our marine mammals.
Flashback to 1981; the UK has just banned the use of polychlorinated biphenyls or PCBs. The chemicals had been widely used for a host of applications and indeed Europe housed many PCB production plants until the 1970’s when the carcinogenic properties of them became more widely known. That was over thirty years ago, so why are we now talking about them again?
The simple answer: these chemicals are so persistent that they are still getting into our marine environment.
PCB’s are carcinogenic, so you can imagine the impacts their presence can have on the wildlife in our oceans. A survey of 1,000 whales, dolphins and porpoises recently revealed that their blubber contained some of the highest concentrations of the contaminant in the world. Being top predators they are particularly susceptible as the toxins have accumulated all the way up through the food chain, from the bottom feeders to the tuna shoals, resulting in whales and dolphins receiving the largest doses.
Anyone familiar with Rachel Carsons Silent Spring will know that long lasting chemicals can wreck havoc upon wildlife and humans alike, and are even present generations later having being passed down from mother to child. In the case of Europe’s marine mammals this is not a problem as it appears the PCB levels are preventing them from breeding. The UK’s last pod of killer whales is a prominent marker of this. The pod of eight have not produced a calf in the 19 years they have been studied.
It is not just the UK’s pod that isn’t breeding. Researchers were surprised to find that PCB levels were the same for males and females. As PCBs are stored in fat, females are able to get rid of the toxins, passing them down to their offspring in the high-fat milk they feed them. Therefore the high levels still present in females is a marker of reproductive failure.
Again it doesn’t take a genius to work out that any population that doesn’t breed only has a limited time left on Earth. Paul Jepson, at the Zoological Society of London (ZSL) fears the worst; claiming that the UK’s pod “will go extinct.” Although nobody is sure when this will happen as killer whales have a long-life span it seems almost inevitable given the concentrations they have been subjected to. As for Europe’s other populations, they are also at high risk of extinction.
Moreover this study highlights that a simple ban cannot make evil disappear. 30 years later and despite a drop in concentrations of PCB there is clear evidence it is still entering the environment probably from a variety of sources. Of the 300,000 tons produced in Europe much of it is still in the land and could still enter our oceans.
Clearly a solution is needed, PCB is an extreme example of how management as well as legislation is needed to prevent the impacts of detrimental chemicals in the environment. Whether it be making sure PCB is correctly buried, or thinking about how disturbing the seabed through drilling or dredging may release high levels of the toxin; governments need to act swiftly and effectively to prevent extinctions within the marine environment.
Featured Image by ZSL
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