High levels of mercury have been found in whales caught off Japan's coast. Experts have noticed that the levels of the metal are highest in mammals snared in southern waters. The mercury density in the meat of one whale measured more than 57 times the prescribed safety limit.
Tetsuya Endo, a lecturer at the Health Sciences University of Hokkaido, feels the whales may be consuming and accumulating mercury dissolved in seawater. Tetsuya cites industrial pollution in Japan and southeast Asia along with undersea volcanic activity as the probable causes for the presence of mercury in the ocean waters.
Researchers analysed mercury density in 83 slices of whale meat bought from six regions between 2000 and 2002. They found that every slice exceeded Japan's prescribed limit of 0.4 parts per million (ppm) for the maximum density of mercury. They also discovered higher than permissible limits of methyl mercury, which is known to affect the human nervous system.