Highly radioactive strontium was detected in the groundwater at the crippled Fukushima No. 1 nuclear power plant for the first time, Tokyo Electric Power Co. said June 12.
TEPCO said strontium was also found at five locations in the sea around the plant.
Although strontium had previously been detected in soil on the plant's premises, a sample collected on May 18 from groundwater around the No. 1 reactor showed 0.078 and 0.022 becquerel of strontium-89 and strontium-90, respectively, per cubic centimeter.
Another sample from groundwater near the No. 2 reactor showed 19 and 6.3 becquerels of strontium-89 and strontium-90, respectively, per cubic centimeter.
The substance, leaked from the plant's reactors, is believed to have seeped into the groundwater via rainfall.
The radiation level of strontium detected in the sea areas was measured at up to 240 times the safety standard.
A seawater sample gathered on May 16 from around an intake outlet of the No. 1 through No. 4 reactors contained 26 times the safety standard for strontium-89 and 53 times the standard for strontium-90.
The radiation levels of strontium-89 and strontium-90 were also measured at 67 times and 117 times their safety standards, respectively, at an intake outlet of the No. 2 reactor.
At an outlet of the No. 3 reactor, the levels were 80 times the standard for strontium-89 and 240 times the strontium-90 standard.
Since strontium has a half-life of 29 years, it can accumulate in bones over a long period.
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