wAbstract
@This study reports on the physico-chemical properties and concentrations
of major, minor and trace elements (Si, Al, Fe, K, Na,Mg, Ca,
Ti, Ba, Mn, Cr, Sr, Zr, Zn, Ni, Y, Li, Cu, Co, Nb, Ga, Th, Sc,
Mo, W, Be, Ge, Ta, Bi, Se, Te, and Re) in tropical topsoils (0-10
cm) of the Terengganu River basin, Malaysia. Soils were observed
to be mildly acidic (average pH1:5 `5.4)
with loam to sandy loam texture, and exhibited low CEC (average
`2.25 cmol(+)/kg) and low organic matter
contents (average LOI `3.0). NE monsoonal heavy rains and annual
flooding remove finer particles leaving soils with a high sand
size fraction (average `52.46) rich in quartz.
@Under the humid tropical conditions most of the metals from the
topsoil layer, especially alkali and alkali earth metals (e.g.
Na, Ca, Mg, Sr, Ba), are significantly depleted by preferential
leaching and/or plant uptake. The average concentrations of Si,
Cr, Zn, Ni, Mo, W, Bi, Se and Te were measured to be higher in
soils as compared to the upper continental crust. Mineral deposits
associated with granite rock also contribute to the elevated levels
of metals apart from cases where the soil geochemical processes
enrich metals by fixation on the secondary Al-Fe-(hydro)oxides.
@Soils developed on granite rock registered higher concentrations
of most of the elements investigated throughout the four main
geological units in the Terengganu River basin. Principal component
analysis (PC1, 91.9 and PC2, 5.90) revealed that the element
concentration and distribution are primarily influenced by the
local geology and soil texture. Most of the metals investigated
registered concentrations well below the guideline values with
the exception of Mn, Cr, Ni and Ba which exceeded the permissible
levels. Higher Cr concentrations (average `94.89 mg/kg) seemed
to be introduced into soils by the use of pesticides (e.g. CCA)
as a wood preservative at a few location. Soils developed on metasedimentary
rocks registered higher W concentration (average `2.3 mg/kg) as
compared to other rock units, probably as a result of the presence
of mineral scheelite (CaWO4) as revealed
by SEM analysis.
@This work presents the local and regional geochemical baseline
values of 32 major, minor and trace elements of tropical surface
soils of the NE region of Peninsular Malaysia.
Keywords: Surface soils; Tropical; Metals; Geochemical baseline;
Environment; Malaysiax
1. Introduction
2. Study area
@2.1. Site description
@2.2. Geology
3. Methods
@3.1. Sampling
@3.2. Analytical
4. Results
@4.1. Soil properties
@4.2. Major, minor and trace elements
5. Discussion
6. Conclusions
Acknowledgements
References