Pollution causing cancer in animals, new report warns

Dumping of toxic wastes is contributing to cancer among wildlife, a new report says.

Scientists say that tumors on beluga whales, sea lions and other animals are a warning signal. They call these animals “sensitive sentinels of disturbed environments.”

The report, "Wildlife Cancer: a Conservation Perspective," published in the July edition of the cancer research journal Nature Reviews Cancer, cites growing evidence from around the world that pesticides, coolants and other toxic chemicals are causing a variety of severe tumors in animals.

For example, the sea lions that are a major tourist attraction at San Francisco’s Pier 49 are being diagnosed with deadly tumors around their rear flippers and anuses. Frances Gulland, director of veterinary science at the Marine Mammal Center in nearby Sausalito, told Newsweek her center periodically gets calls from the pier reporting sea lions crippled by horrible swellings. Gulland said 17 percent of the sea lions brought to the center from the pier die of renal failure or paralysis caused by tumors that travel up the genital tract and push against the kidney and spine.

According to the journal article, sea lions that died of genital carcinoma had an 85 percent higher concentration of toxic PCBs in their system than other sea lions. PCBs, polychlorinated biphenyls, are chemicals used in coolants and electrical transformers.

Gulland said that blubber samples of sea lions who died of cancer also show high concentrations of the pesticide DDT. Many sea lions are born near the Channel Islands, where 1,700 tons of DDT were dumped before it was banned in 1972.

In Canada’s St. Lawrence Estuary, cancer was found to be the second leading cause of death among dead beluga whales that were found beached or drifting out to sea. The Saguenay River, which flows into the estuary, is lined with aluminum smelters. The smelters are heavy producers of polycyclic aromatic hydrocarbons (PAHs), proven carcinogens for humans as well as animals.

Belugas feed from the bottom of the estuary, eating creatures like the blue mussel. Blue mussels in the Sanguenay River area had PAH concentrations 200 times higher than in adjacent areas.

It’s not just the whales. Smelter workers there have shown high rates of lung cancer, while people in the area who drank from taps supplied with surface water developed stomach and intestinal cancer.

"The more we contaminate the environment, the more we will see problems," Gulland told Newsweek. "If you dump a pollutant, it doesn't just go away."

The report’s authors, biologists Denise McAloose and Alisa L. Newton, work for the Wildlife Conservation Society’s Global Health Program.

McAloose, like many other scientists, sees a connection between the environmental role in cancer among wild animals and cancer prevention among humans. "We need collaboration and cooperation across conservation organizations, public-health communities, as well as governments to make changes that have positive outcomes for animals and the planet," she told Newsweek. "Because that will have positive impacts on the human population."