Can I track Cs, U, Pu, and Pu apart from I in soil samples from Fukushima Prefecture, Japan?

In the present study, I activities and I/I atom ratios were measured in 60 soil samples contaminated by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The I concentrations, I activities, and I/I atom ratios in dry-weight were observed to be 0.121-23.6 mg kg, 0.962-275 mBq kg, and (0.215-79.3) × 10, respectively. The maximum values of both I activities and I/I atom ratios in Japanese soil increased about three orders of magnitude due to this accident. The equation logy = 0.877logx + 0.173 (Pearson's r = 0.936; x, I concentration; y, I concentration; decay-corrected to March 11, 2011) instead of a simple constant may be a better way to express the relationship between I and I in Japanese soil affected by both global fallout and FDNPP accident fallout. In addition, a moderate correlation was observed between I and Cs (logy = 0.624logx + 1.01, Pearson's r = 0.627; x, I activity; y, Cs activity). However, I presented larger fractionations with less volatile radionuclides, such as U, Pu, and Pu. These findings indicated Cs could be roughly estimated from I or I; this is advantageous as fewer Cs data are available and Cs/Cs is being considered a promising tracer during radiocesium source identification.