Killer whales are accumulating high levels of contaminants

A study published by Wiley has found extremely high levels of contaminants in killer whales. The researchers identified new types of flame retardants that accumulate in the tissues of killer whales near Norway and are also passed on to nursing offspring.

“The study is shedding new light on how predators in the top of the food chain are affected by environmental contaminants, which has remained largely unknown,” wrote the study authors.

“Little is known of the movement or presence of unregulated, emerging contaminants in top predators. The aim of the present study was to conduct the first screening of legacy and emerging contaminants in multiple tissues of killer whales from Norway and investigate tissue partitioning and maternal transfer.” 

“Blubber was collected from 8 killer whales in 2015 to 2017, in addition to muscle from 5 of the individuals, and kidney, liver, heart, and spleen from a neonate.”

In addition to flame retardants, the experts detected man-made chemicals called perfluoroalkyl substances (PFAS) in the tissues of adult killer whales. This chemical has been linked to reproductive and endocrine effects in wildlife. 

The researchers also found polychlorinated biphenyls (PCBs) in the blubber of 7 of the 8 killer whales in the study. PCBS were detected at levels that exceeded the proposed threshold for toxicological effects in marine mammals. The manufacturing of PCBs was banned in 1979.

“Top predators such as the killer whale (Orcinus orca) are considered sentinel species for marine ecosystem health, and many killer whale populations have been evaluated as being at risk from the harmful effects of legacy POPs, such as PCBs,” wrote the study authors. 

“Levels of pollutants in top predators give not only an indication of ecosystem health, but of the persistence of chemicals, passive mobility in the environment, and active biotransport with migrating animals.”

“Our results are relevant for the continued environmental monitoring of contaminants in the Arctic.”

The study is published in the journal Environmental Toxicology and Chemistry.

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By Chrissy Sexton, Earth.com Staff Writer