By Hannah Priest
The killer whale is at the top of the food chain when it comes to marine animals, which is the main problem when discussing the effects of PCBs. When, the chemicals enter the ocean they are first absorbed by plankton, and the level of PCB increases in each animal that consumes it. As a result, Killer whales absorb the highest amount of PCB pollution as they continue to consume the different prey in their food chain – from fish, to seals and sharks.
Polychlorinated biphenyl (PCB) has been mass produced and manufactured from the 1920s through to 1981, when they were finally banned here in the UK. Over the course of three decades, Europe alone produced over 3000 tonnes of PCB. The issue now being that the majority has yet to be safely destroyed or put in safe places.
Even though PCBs have been banned for decades, they are still continuing to pollute and harm marine mammals and the ocean as a whole. Since it was used in everything from paint to plastics to electrical equipment, it is extremely difficult to erase the presence of PCBs in our oceans.
In order for the Killer Whale species to continue thriving in our oceans they must be able to reproduce. However, it has been shown in recent studies that the pollution of PCBs in the Killer whales’ diets has had a significant effect on their ability to reproduce, as they stunt the production of female orcas’ ovaries. Moreover, PCBs are easily passed down from the mother orca to its new-born through the mother’s milk. This means that the pollutants remain to exist in the mammal’s bodies, continuing the harmful chain of PCBs being prominent in future Killer whales. As a result, the orcas’ bodies remain full of pollutants that are far more persistent than the animals themselves are.
Although it is difficult to control the level of PCB when in enters the ocean there are steps and precautions that can be taken to prevent it entering the environment. Certain areas including Europe urgently need to address the placement of the banned PCB products by destroying or placing them away safely urgently. By doing this the amount of PCB entering our oceans will drastically decrease.