Sixteen topsoil samples from Bukit Jernih, Gua Kelam and Bukit Merah were analysed for their major elements and heavy metal composition, together with several physico-chemical parameters. Major elements determined were SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5, whereas heavy metals determined were As, Co, Cu, Cr, Ni, Pb and Zn. Physico-chemical parameters determined were percentage of organic matter, clay, silt and sand composition, pH and electrical conductivity. The results showed that the average soil pH in limestone soil was between 6.38 to 6.93, whereas average soil pH in quartzite soil was 6.23. The average soil electrical conductivity for all sampling stations was below 1.7 mScm-1. High organic matter content average was shown in soil samples from Bukit Jernih (7.45%), followed by Gua Kelam (5.21%) and Bukit Merah (3.31%). Soil samples from Bukit Jernih and Gua Kelam showed a clayey texture with more than 35% clay content, whereas soil from Bukit Merah was sandy in texture with more than 67% sand content. In general, soil samples from limestone area of Bukit Jernih and Gua Kelam recorded higher content of heavy metals compared to quartzite soil from Bukit Merah. The average concentration of Cr and Co at Bukit Jernih at 413 µg/g and 88 µg/g, respectively, whereas the concentration at Gua Kelam was 152 µg/g dan 76 µg/g. These concentrations exceeded the potential toxic concentration in soil. The main major elements were SiO2 followed by Al2O3 and Fe2O3. SiO2 content in quartzite soil from Bukit Merah(89.45%) was higher compared to limestone soil from Bukit Jernih (59.74%) and Gua Kelam (53.16%). Nevertheless, Al2O3 and Fe2O3 content in limestone soil was higher compared to quartzite soil. The percentage of easily ignited content in limestone soil was two fold higher than quartzite soil. Other major elements were less than 2.5%. The study showed that enrichment of Cr, Zn, Pb, Ni and Cu in soil was influenced by the presence of SiO2, Al2O3 and Fe2O3.
Keywords: Enrichment; heavy metals; limestones hill; major elements; toxicity