Kepekatan Kandungan Logam Berat dalam Tanih di Tapak PelupusanSampah Sg. Kembong, Bangi, Selangor(Heavy Metal Concentration in Soil at Sg. Kembong Landfill, Bangi, Selangor)

The distribution of heavy metals in soils, physico-chemical properties of soils and 2D geoelectrical resistivity survey at Sungai Kembong sanitary landfill were analyzed in order to investigate the effect of heavy metals in the leachate around the dumping site. A total of 30 soil samples were collected for physico-chemical and heavy metals analysis by hand auger from a depth of about 60 cm in the ground within the covered inactive landfill. Geoelectrical resistivity survey was carried out using Wenner electrode array and 2-D imaging technique. Electrode spacing used was 5 m along 300 m line. The soil samples contained about 25 – 75% of sand, 4 – 40% of clay and 19 – 67% of silt. Results of heavy metals analysis showed that the concentrations of Cu, Pb and Cr were higher than the background level while other metals such as Ni, Co, Cd, Zn and Fe were lower than the background values. The range of Cu concentrations is 2-326 μg/g while Pb and Cr are 3-78 μg/g and 4-76 μg/g, respectively. The range of resistivity based on 2D inversed model along the survey line is from 5 Ωm to 105 Ωm. Resistivity values of 3 to 5 Ωm were interpreted as representing leachate plume. The width of leachate plumes was between 20 to 100 m. The average value of CEC is from 1.7 to 3.8 meq/100 and thepH value ranged from 4 to 7. The electrical conductivity is in between 1910 to 5525 μS/cm. The organic matter in the soil is ranged from 0.3 to 5.6%. Muscovite, quartz, kaolinite and orthoclase minerals were found dominant in the XRD patterns of the samples. These minerals were interpreted as coming from the covering metasediment soil taken from the surrounding areas. These results showed that the soil cover used in the dumping site managed to control the heavy metals from infiltrating into the surrounding areas.