Soil samples from 11 sites surrounding Japan's severely damaged Fukushima Daiichi nuclear plant have shown traces of strontium, Japanese regulators reported.
The fission byproduct is always present with certain levels of cesium, which was detected in earlier soil samples. Over time, strontium isotopes can accumulate in bone, and they have been linked to leukemia and other cancers. But government scientists quoted by the Asahi Shimbun indicated the samples did not contain concentrations high enough to immediately affect human health, adding that government limits for cesium in crops also ensure strontium levels are safe.
Soil samples from the Akogi district showed the highest levels of the contaminant, with 250 becquerels of strontium-90 per kilogram and 1,500 becquerels of strontium-89. The prior has a half-life of 29 years and the later a half-life of 50 days.
Samples taken in April and May also showed levels of strontium-90 at 120 becquerels per kilo of soil at Iitate, 36 kilometers from the plant, and at 77 becquerels per kilo in the city of Fukushima, 62 kilometers from the plant.