Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/144131
Title: Assessment of Soil Heavy Metal Concentrations within the Nee Soon Swamp Forest
Authors: Teo Wei Tian Charlene
Keywords: Heavy Metals, Vertical Distribution, Land Use, Total Organic Carbon, Soil pH, Clay Minerals
Issue Date: 2016
Citation: Teo Wei Tian Charlene (2016). Assessment of Soil Heavy Metal Concentrations within the Nee Soon Swamp Forest. ScholarBank@NUS Repository.
Abstract: The accumulation of heavy metals in soils as a result of anthropogenic activities is a serious concern due to their persistence and toxicity. This study investigated soil heavy metal concentrations from five sites within the Nee Soon Swamp Forest (NSSF), Singapore: a firing range, golf course, along an expressway, a water pipeline, and an undisturbed secondary forest which served as a proxy for background concentrations. Mobilization of heavy metals were studied through analysis of heavy metal concentrations at depths of 0–10cm, 20–30cm, 40–50cm and 90-100cm. Ten heavy metals were used for analysis: Pb, Cu, As, Zn, Ni, Sr, Sn, Mn, Cr and Ba. Enrichment factors (EF) were used to analyze the degree of contamination. Soil physical-chemical properties such as total organic carbon, clay fraction and pH were determined to examine their influence on heavy metal occurrence. The firing range was enriched (EF>2) in Pb, Cu, As, Sr, Sn; expressway in Cu, Sr, Zn, Ba, Ni, the golf course in Cu, As, Cr, Sr, Ba, and water pipeline in Cr. Across all land uses, organic carbon content decreased with depth and was associated with heavy metal accumulation on surface soils. The median clay fraction was 29% in surface soils, which were sandy clays or sandy clay loams. Surface soils were generally acidic with a median pH of 4.96. High heavy metal concentrations down to depths of 50cm indicate leaching, which was attributed to natural soil conditions such as kaolinite mineralogy and acidity. However, high subsurface concentrations at depths of 100cm at some locations reflect another source of contamination - the introduction of extraneous materials as a result of land cover change. Comparing each land use with other studies, lower heavy metal concentrations obtained in this study were mainly due to variations in sampling locations.
URI: http://scholarbank.nus.edu.sg/handle/10635/144131
Appears in Collections:Bachelor's Theses (Restricted)

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