If you're up on your orca news, you've likely seen the sad reports about the young female killer whales that recently passed away from the well-known J-pod.
Unfortunately, that orca pod and many others may soon experience even more loss.
A new study published in Science estimates that 50 percent of the killer whale population could be doomed thanks to a banned toxin leaching from the water into their bodies.
Polychlorinated biphenyls, otherwise knows as PCBs, were once widely used industrial chemicals, according to the National Ocean Service. They could be found in everything from household appliances to insulators and capacitors.
And then humans found out how terribly, terribly dangerous PCBs were.
NOS reported that PCBs were banned in 1979 in America after their true impact was realized. Of course, that wasn't before 1.5 billion pounds were created to stick around in the environment for years and years to come.
The Science study reports that orcas have retained these PCB toxins in higher amounts than most of the mammals in the world. The problem lies in their blubber. It stores the PCBs that they intake from their food, which got it from the smaller food it ate and so on down the food chain.
By the time the toxins reach the orcas, they're in highly concentrated amounts.
The Conversation reported that these chemicals have worked their way around the globe. They can evaporate into the atmosphere and return later in rain, which has spread the toxins to the deepest seas and coldest parts of the arctic.
And the problem will likely continue to worsen for the orcas, because PCBs aren't banned worldwide.
According to CNN, 152 countries pledged to eliminate PCB use by 2025, but the orcas could be well on their way to the predicted 50 percent population collapse by then.
NatGeo reported that, because the toxins are stored in the whales' blubber, the chemicals get released into the bloodstream when the whale burns fat by going hungry or exercising vigorously — like when the swim hard during a hunt.
When the PCBs hit their blood, it decreases immune function, leaving them open to disease. It can also be a neurotoxin and affect the whales' brain function. Plus, it can reduce reproduction. Even if the whale does successfully have a child, the mother can pass PCBs to the young calf via her milk.
As Azula previously reported, "Blue Planet II" explored how toxic milk may have killed a young pilot whale.
The docuseries then showed the grieving mother carrying her dead baby for miles — much like that killer whale did earlier this summer.
The idea that 50 percent of all killer whales are headed toward disaster in the next few decades is terrifying, but the study also gives us a rare chance to step in before it's too late.
Perhaps the 152 countries who pledged to get rid of PCBs by 2025 will do so sooner now that they have this information. And hopefully politicians will enact laws to protect killer whales from all the other things that are harming them so as to decrease their risk of dying from other causes.
Studies like these can seem like doomsday studies, but they're really just delivering valuable information to us so we, as a collective humankind, can act.