Toxic chemicals linked to sea lion cancer

An aggressive cancer affecting California sea lions has been linked to DDTs and PCBs dumped into the Pacific Ocean decades ago. Credit: BLM

Researchers believe a cancer that has killed sea lions in California for years is linked to toxic chemicals in the water. After two decades of research, scientists concluded a previously unknown herpes virus was triggering the cancer, and sea lions (Zalophus californianus) with higher concentrations of DDT, PCBs and other chemicals dumped into the Pacific Ocean decades ago were more prone to succumbing to it. They published their research in Frontiers in Marine Science.

“They’re predisposed to cancer by these high levels of legacy compounds that are still in the environment — and we are also exposed to these chemicals,” University of California Davis research associate Frances Gulland told the Los Angeles Times.

The aggressive cancer is highly prevalent among California sea lions. The nation’s largest DDT manufacturer used to dump its waste near the Channel Islands where many of the sea lions breed and feed their young.

Read more from the Los Angeles Times.