It's been two years since a devastating magnitude 9 earthquake hit Tōhoku, Japan in March 2011, of which a resulting tsunami erupted and seriously impacted the Fukushima Daiichi nuclear power plant. Japan is now grappling after it found out that the groundwater at the nuclear plant contained above average levels of a radioactive substance called strontium-90.

Strontium-90, a byproduct of the fission of uranium and plutonium in nuclear reactors, even nuclear weapons, was detected in groundwater near the plant at levels 30 times greater the government safety standard, according to officials on Wednesday. People who get exposed to it are at a greater risk of developing cancer.

What's more, even sea animals could be at risk.

"This contaminated water should not be released to the ocean," Michiaki Furukawa, a nuclear chemist and professor emeritus at Nagoya University, said. "They have to keep it somewhere so that it can't escape outside the plant."

Tokyo Electric Power Co. (TEPCO), which maintains the nuclear power plant, maintained the high levels of strontium may have entered the environment after water poured over the melted fuel in Unit 2 and leaked out through the reactor building.

It did admit though that the levels of strontium-90 in groundwater had jumped by 116 per cent since December. It is not sure if the groundwater at the well, located 27 metres from the sea, has not affected yet the nearby seawater.

The utility has yet to find the cause of such high levels of contamination, according to Takeo Iwamoto, a TEPCO spokesman.

"TEPCO needs to carry out more regular testing in specific areas and disclose everything they find," the nuclear scientist added.

The latest findings are sure to complicate prevailing efforts by TEPCO in securing approval from local fishermen to allow it to dump groundwater into the Pacific Ocean. Japanese local fisherman have remained wary of the operator's plans and have consistently refused to give TEPCO permission to carry out the operation.

To counter new latest problem, TEPCO proposes to inject chemicals into the ground, between the well and shore, to battle the contaminated water from reaching the ocean.

Explosions around the plant at the height of the 2011 crisis excreted large amounts of radioactive material not only to the atmosphere but most importantly to the surrounding land and ocean. The plant suffered meltdowns at three of its six reactors.

Japan has about 50 working nuclear power plants prior to the 2011 accident. All but two have been shut down, pending a review of safety procedures.