Thirty Aridisol soil samples of the Kawaihae soil series on the
dry, leeward, northwestern side of the island of Hawaii and 13 Histosol samples
of the Papai series on the wet, windward, eastern side of the island were subjected
to (1) complete dissolution by a mixture ofHN03, HCl, and HF to determine
total concentrations of Co, Cr, Cu, Fe, Mn, Ni, and Zn and (2) extraction of these
metals by shaking 10 g soil: 100 mL 0.5M HCl solutions for 16hr to determine
nonresidual concentrations. Analyses were performed mainly by flame and
electrothermal atomic absorption spectrophotometry. Loss on ignition (LOI)
and soil pH were also determined.
Total metal concentrations, quantity extracted, LOI, and soil pH were analyzed
statistically. Compared to the Histosol, the Aridisol samples typically contain
more Co, Cr, Fe, and Mn, less Cu, similar concentrations of Ni and Zn, and
have less LOI and higher pH. The Aridisol exhibits a high degree of correlation
between total Cr and Ni, while a strong negative correlation occurs between Cu,
Mn, Co, and Fe individually with LOI in the Histosol. The mean concentrations
of these metals in both soils are significantly greater than those which occur in
soils of the conterminous United States.
The effectiveness of extraction by the acid solution, as measured by the
percentage of metal extracted, is approximately Mn > Co > Cu > Cr > Fe >
Zn - Ni for the Aridisol and Cu - Zn > Co - Mn > Fe - Ni > Cr for the
Histosol; the difference is attributed to weathering under different climatic conditions.
The latter soils exhibit a higher degree of correlation for percentages of
metals extracted among the various metals and with LOI
