URANIUM, THORIUM AND RARE EARTH ELEMENTS DISTRIBUTION IN FUKUSHIMA SOIL SAMPLES

Area of Science:

• Environmental Science
• Geochemistry
• Nuclear Chemistry

Background:

• The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident released various radionuclides and elements into the environment.
• Understanding the distribution and concentration of elements like uranium, thorium, and rare earth elements (REEs) in soils is crucial for environmental monitoring.
• Previous studies have focused on radioactive contamination, but baseline data for REEs in post-accident soils is less established.

Purpose of the Study:

• To determine the concentration levels of uranium, thorium, and REEs in soil samples from areas affected by the FDNPP accident.
• To establish background data for REEs in soils following the FDNPP event.
• To investigate potential correlations between FDNPP accident and REE concentrations in soil.

Main Methods:

• Soil samples were collected from areas contaminated by the FDNPP accident.
• Inductively coupled plasma-mass spectrometry (ICP-MS) was employed to quantify uranium, thorium, and REEs.
• Chondrite-normalized REE patterns were analyzed to assess enrichment.

Main Results:

• ICP-MS analysis provided detailed concentration data for uranium, thorium, and REEs in the studied soil samples.
• Chondrite-normalized REE patterns did not reveal significant enrichment attributable to the FDNPP accident.
• Elevated concentrations of these elements at specific locations were likely influenced by the soil formation process from granitic parent rocks.

Conclusions:

• The study established baseline concentrations of uranium, thorium, and REEs in FDNPP-affected soils.
• Observed REE patterns suggest that geological factors, specifically soil formation from granitic rocks, are the primary drivers of elemental concentrations, not the nuclear accident.
• This research provides valuable geochemical data for future environmental assessments in the Fukushima region.