Volume 31, Issue 3 (July 1986)
Morphological Analysis of Opal Phytoliths for Soil Discrimination in Forensic Science Investigation
A morphological analysis of opal phytoliths in soils was applied to forensic science soil discrimination. To examine a variation of opal phytolith composition with a difference of land use or topography, a region was chosen in a range of 5 km covering from diluvial plateau to alluvial plain. Opal phytolith compositions in soil samples collected from the same site were similar. On the other hand, there were obvious differences in the compositions between soils from different sites. In the region examined, contents of Chloridoid, Bambusoid, Fan-shape, and Elongate classes varied with sampling sites allowing us to discriminate the samples from different sites. Festucoid and Point-shape class were small in the amounts to be compared for the soil discrimination. Morphological analysis of opal phytoliths was effective to discriminate soil samples that came from different land use, even though they were indistinguishable by their mineralogical characteristics. About 2 mg of opal phytolith fraction, 10 to 200 µm in diameter, less than 2.3 in specific gravity, was a sufficient amount for the morphological analysis.