The 36Cl/Cl ratio depth profiles of soil samples collected at both of Makabe-town and Tokai-mura were also measured. Since Makabe-town is located about 50 km apart from Tokai-mura, we do not expect it to be affected by the nuclear facilities. No large variations were observed in the Makabe depth profile; the measured ratios ranged from 3 to 5 × 10−13. The result obtained for Tokai-mura is significantly different in that from the surface to about 80 cm depth, the measured ratios, 10−12, are much higher than any at Makabe. At depth below 80 cm, the Tokai-mura ratios are lower and become indistinguishable from those at Makabe.
The 36Cl/Cl ratio in unaffected areas of Japan is estimated to be 3–4 × 10−13.