Scientists in California have found the reason behind the mysterious cancer that has killed sea lions for several years. According to a recent report, a team of marine mammal pathologist, chemist, virology experts and geneticist found that the causes include toxic chemicals, like DDT, in the ocean and herpes.
The likely conclusion came after two decades of investigation and research. As of now, around 25 percent of sea lions that first responders brought to the Marine Mammal Center in Sausalito died because of aggressive cancer. The research revealed that Herpes and toxic chemicals such as DDT and PCBs poisoned the California coast decades ago.
According to researchers, the ocean has been hurting these creatures and mysterious cancer in so many sea lions also raised warning for humans, reported LA Times.
Radioactive Material and Industrial Trash
Cancer in sea lions was detected decades ago. At that time radioactive materials, barrels of industrial trash, oil refinery waste, rotting meats and various acidic materials were being dumped in the ocean.
"Sea lions, they're coming up on the beach, using the same waters that we swim and surf in, eating a lot of the same seafood that we eat. They're predisposed to cancer by these high levels of legacy compounds that are still in the environment â and we are also exposed to these chemicals," said Frances Gulland, a University of California researcher serving on the U.S. Marine Mammal Commission.
Along with other scientists, Gulland cataloged 394 sea lions and found that a previously unknown herpes virus was causing cancer. The team of experts also confirmed that sea lions are more prone to life-threatening disease when their blubber contained higher concentrations of chemicals including DDT, an odorless crystalline chemical compound that became infamous for environmental impacts, and PCBs, which had been used in electrical and hydraulic equipment.
Padraig Duignan, chief pathologist at the Marine Mammal Center and a co-author of the study said that the levels of pollutants in the marine animals in California "is extraordinary". According to him, it is the main reason behind the increased level of cancer.
Duignan explained that the dumping activities between World War II and the 1970s left a lot of pollutants in the ocean. "These legacy chemicals haven't broken down anything appreciable in intervening years, and nobody knows if they ever will. This is something that they're going to have to be exposed to for who knows how long," he said.