Radiation in Japan Seas: Risk of Animal Death, Mutation

n the past week, seawater samples taken near the nuclear power plant, on Japan's eastern coast, have shown elevated levels of radioactive isotopes, including cesium 137 and iodine 131, according to the New York Times. (See "Japan Tries to Avert Nuclear Disaster.")

All life on Earth and in the oceans lives with exposure to natural levels of ionizing radiation—high-frequency radiation with enough energy to change DNA. Most such genetic damage heals, but the addition of human-made radiation can make it harder for the body to repair broken genes.

Radiation concentrations in the Japanese seawater samples have fluctuated in past days, but on Wednesday the amount of iodine spiked to 3,355 times the legal limit for seawater, Japanese nuclear safety officials told the Associated Press.

That level is the highest so far—and an indication that more radiation is entering the ocean, though how is still unknown, the agency reported. Cesium was also found to be 20 times its safety limit on March 28, according to the Times.

Radiation Can Cause "Bizarre Mutations"