Shark Oil Contaminated by VCR Chemical

April 21, 2008 -- A flame retardant found in everything from consumer electronics to furniture is contaminating waters where sharks swim and winding up in fish oils sold as nutritional supplements, according to a new study published in the journal Food Chemistry.

Scientists led by Kensaku Kakimoto of the Osaka Prefectural Institute of Public Health in Japan analyzed fish oils purchased from Japanese markets for the presence of the potentially toxic chemical hexabromocyclododecane (HBCD).

The researchers first chemically separated the oils into their basic ingredients, and then used mass spectrometry, a process that looks at charged particles, to identify the presence of HBCD.

They found it in 15 of the 22 samples. While concentrations varied, some sardine and shark liver oils from fish captured near Japan contained "relatively high levels of HBCD, indicating that both the surface and deep seawaters around Japan may have been contaminated," the researchers wrote.

It's unknown how the chemical wound up in the water, but an event as simple as someone dumping a VCR into a landfill could contribute to the problem, since rainwater could wash the chemical into oceans or the chemical could vaporize and enter the atmosphere, according to Tim Fitzgerald, an Environmental Defense Fund marine scientist.

Shark liver oil manufacturers don't always state what species the oil came from, but it is commonly derived from deep-sea sharks, dogfish sharks and basking sharks. As the name suggests, the oil is extracted from the livers, which can make up about 25 percent of the shark's total body weight.

Although certain chemicals in shark liver oil have been studied as immune system stimulants, there is little medical evidence to support some of the oil's purported health benefits, which range from treating radiation sickness to pimple breakouts to cancer.