Long-term pollutants are making their way to baby dolphins via their mother's milk!

For most mammals, the mother's milk serves as the first form of nutrition they will encounter. Without the nascent ability to procure food from the get-go, this milk is quintessential nutrition for the younguns to begin their journey into adulthood and escape from dependency.

However, increasing pollution levels have begun to contaminate even this pillar of purity. A team of marine biologists from the National Oceanic and Atmospheric Administration (NOAA) have found that dolphins have started producing milk tainted with high amounts of persistent organic pollutants (POP), which inadvertently ends up being consumed by their calves.

These long-term pollutants are a menace to aquatic life, accumulating in the blubber of marine mammals, eventually leading to severe ailment and death in many cases. Due to bioaccumulation, species at the top of the food chain often suffer from the highest amounts of such contaminants in their bodies. And now, we have witnessed this being inevitably passed down from parent to child as well.

The study's authors reached this dreadful conclusion while working with semi-wild dolphins belonging to the US Navy's Mammal Program, a project to assess the military viability of these animals. These marine mammals are considered semi-wild since they are left free to swim around San Diego Bay, but are blocked off further via fences.

Collecting milk from six mother dolphins and blood samples from their calves over almost a year and a half showed that there was a massive amount of POPs in the mother's milk and the calves’ blood. By the time the babies moved to adult food, they already had a considerable amount of POP in their fatty tissues — even higher than their mothers!

Mother dolphins don't get to enjoy maternity leave, continuing to hunt and eat prey rich in the POP-riddled waters while nursing their young. As a result, these pollutants continually become absorbed by their bodies, eventually making their way into the milk consumed by the young.

Such an increasing level of body contaminants is undoubtedly dangerous and can place a massive toll on the dolphins, leaving them susceptible to a host of medical conditions across many parts of the sea. Further, the scientists warn that orcas might be faring similarly since they too tend to hunt prey while nursing their calves, while being at the tippy top of the marine food chain.

The findings of this research have been published in $4 and can be accessed here.