Researchers have spotted trace amounts radioactive compounds of cesium-134, in coast of Eureka in northern California. The compounds leaked due to the Fukushima Daiichi Nuclear Power Plant accident that was caused by the 2011 earthquake and tsunami in Japan.

The concentration of derived cesium is very less than the acceptable limits in drinking water set by the US Environmental Protection Agency.

After the March 11, 2011, earthquake and tsunami in Japan, the power supply to the water pumps got disconnected in nuclear power plant. Water pumps were used to cool the nuclear fuel in the plant's six reactors.

After the calamity, cesium-134 and other radioactive elements were released into the ocean. Then the radioactive material moved across the Pacific Ocean.

"We detected cesium-134, a contaminant from Fukushima, off the northern California coast. The levels are only detectable by sophisticated equipment able to discern minute quantities of radioactivity", said Ken Buesseler, a Woods Hole marine chemist who is leading the monitoring effort.

The radioactivity detected near the damaged nuclear power plant is 10 million times more than the recently detected in Northern California.

Woods Hole marine chemist Ken Buesseler said most people were unaware that radioactivity was detected in Pacific waters even before its detection in Fukushima. But cesium-137 was only the radioactive material detected at that time. He told that cesium-137 undergoes radioactive decay with a 30-year half-life and during atmospheric weapons testing in the 1950s and 1960s, it got introduced to the environment.

Cesium-134 is now detected along with cesium-137. This isotope is also not found naturally. Its half life is of two years. So, it's found only in Pacific from Fukushima, Buesseler added.

According to him, the increase in radioactivity across the ocean is in developing condition and careful monitoring is needed in the matter.