Radioactive strontium up to 240 times the legal concentration limit has been detected in seawater samples collected near an intake at the crippled Fukushima Daiichi nuclear plant, Tokyo Electric Power Co. said Sunday.
The utility said the substance was also found in groundwater near the plant's Nos. 1 and 2 reactors. The government's Nuclear and Industrial Safety Agency said it is the first time that the substance has been found in groundwater.
The agency said it is necessary to carefully monitor the possible effects of the strontium on fishery products near the plant.
Strontium tends to accumulate in bones and is believed to cause bone cancer and leukemia.
Meanwhile, Tepco on Sunday completed preparations to begin testing a newly installed radioactive water treatment system at the Fukushima plant soon, after it finished fixing an adsorption device designed to remove radioactive substances, company officials said.
The utility is expected to begin testing the system, intended to decontaminate highly radioactive water that is accumulating at the site and hampering work to restore the damaged plant, as early as Monday. The company is a couple of days behind the schedule to put the system into full operation, initially planned for June 15, it said.
The utility's preparations to begin testing the system hit a snag Sunday as the amount of water run through the adsorption device was lower than planned, indicating the possibility that piping or other parts may be clogged. The planned level of water recovered later, it said.
The utility is investigating the cause of the snag, the officials said.
Tepco initially planned to begin testing the radioactive water treatment system last Friday but postponed it because water leaks were found in the equipment that day.