Silicon Fractionation of Soluble Silicon in Volcanic Ash Soils That May Affect Groundwater Silicon Content on Jeju Island, Korea

Volcanic ash soils on Jeju Island, Korea, exhibit distinct silicon (Si) fractionation patterns that significantly influence groundwater Si content. Research reveals that while most Si is bound in unavailable forms such as primary and secondary silicates, Andisols—common in high-precipitation regions—show notably higher adsorbed Si concentrations (100–1400 mg kg−1), approximately five times greater than non-Andisols. This suggests enhanced Si solubility in Andisols, potentially impacting groundwater Si levels. The study quantified these fractions using a sequential extraction method, comparing Jeju's volcanic soils with mainland Korean forest soils. It found that amorphous Si was the second-largest fraction in non-Andisols, while pedogenic oxides and hydroxides dominated in Jeju's Andisols, often containing short-range-order minerals like allophane (4–40%). These findings highlight the unique soil formation processes on Jeju Island and their implications for groundwater chemistry.

Park, W.-P., Hyun, H.-N., & Koo, B.-J. (2020). Silicon Fractionation of Soluble Silicon in Volcanic Ash Soils That May Affect Groundwater Silicon Content on Jeju Island, Korea. Water, 12(10), 2686. https://doi.org/10.3390/w12102686