Chemical states of fallout radioactive Cs in the soils deposited at Fukushima Daiichi Nuclear Power Plant accident

Figures & data

Figure 1. Percent fractions of radioactive Cs desorbed from the soils A, B, and C by 1 mole L⁻¹ NH₄Cl solution and 1 mole L⁻¹ CH₃COOH solution, and residual one.

Figure 2. Percent fractions of radioactive Cs desorbed from the soils A, B, and C by 0.001 mole L⁻¹ H₂SO₄ solution and 1 mole L⁻¹ H₂SO₄ solution, and residual one. Arrows show fractions of Cs desorbed by 0.001 mole L⁻¹ H₂SO₄ solution.

Figure 3. Percent fractions of the resided radioactive Cs in the elutriated fraction, the settled fraction less than 106 μm, the fraction between 106 μm and 300 μm, and the fraction larger than 300 μm of the soils A, B, and C after the treatment of 1 mole L⁻¹ NH₄Cl solution and 1 mole L⁻¹ CH₃COOH solution.

Figure 4. XRD patterns of the elutriated fraction (WE), the settled fraction less than 106 μm, the fraction between 106 μm and 300 μm, and the fraction larger than 300 μm of the soils A, B, and C after the treatment of 1 mole L⁻¹ NH₄Cl solution and 1 mole L⁻¹ CH₃COOH solution. Sm: smectite-like clay minerals, M: mica-like minerals, H: hornblende-like minerals, K: kaolinite-like minerals, Q: quartz, O: orthoclose, C: cristobalite, F: feldspar group, S: stishovite (SiO₂), G: gibbsite-like minerals, SL: sodalite-like minerals, OL: olivine, SS: sorosilicate.

Table 1. The representative minerals and clay minerals in the fractions elutriated and sieved in the soils A, B, and C determined by XRD.

Soil A
Size fraction	Elutriated	<106 μm	106 μm << 300 μm	>300 μm
Weight (g)	0.012	0.97	1.38	2.64
Mica-like minerals	•	○	○	•
Kaolinite-like minerals	•	•	•	•
Hornblend-like minerals	▵	•	▵	▵
Smectite-like minerals	▵	▵	▵	▵
Silica minerals	•	•	•	•
Soil B
Size fraction	Elutriated	<106 μm	106 μm << 300 μm	>300 μm
Weight (g)	0.19	0.81	0.87	3.14
Micaceous-like minerals	•	▵	•	▵
Kaolinite-like minerals	▵	▵	▵	•
Hornblend-like minerals	▵	•	•	▵
Smectite-like minerals	•	▵	▵	▵
Silica minerals	•	•	•	•
Soil C
Size fraction	Elutriated	<106 μm	106 μm << 300 μm	>300 μm
Weight (g)	0.36	1.49	1.24	1.92
Micaceous-like minerals	▵	▵	▵	▵
Kaolinite-like minerals	•	•	•	▵
Hornblend-like minerals	▵	•	•	▵
Smectite-like minerals	▵	▵	▵	▵
Silica minerals	•	•	•	•
Note: (•), recognition of clear peak; (○), recognition of small peak, and (▵), recognition of no peak.