Compositions of Dust Fall around Semi-Urban Areas in Malaysia

This study aimed to determine the amount and composition of dust fall in semi-urban areas in Selangor, Malaysia from mid-July to mid-October 2010. The dust fall samples (a combination of dry and wet deposition) through rainwater were collected using polyethylene bottles on a monthly basis so as to determine the concentration of total solids, soluble and insoluble solids from eight monitoring stations. The concentration of cations (Ca2+, K+ and Mg2+) and heavy metals (Pb, Fe, Zn, Al, Cr and Cd) were analyzed using an inductively coupled plasma-mass spectrometer (ICP-MS) while the concentration of anions (F-, Cl-, NO3- and SO42-) in the rainwater was determined through ion chromatography (IC). Results showed that the average concentration of total solids in the dust fall (131.50 +/- 71.95 mg/m(2)/day) below the value of 133 mg/m(2)/day as recommended by the Malaysian Department of the Environment. The dominant anion in rainwater was found to be SO42- followed by NO3-, Cl- and F-, and the dominant cation was Ca2+, followed by K+ and Mg2+. Zn was recorded as the dominant heavy metal in rainwater followed by Fe, Al, Pb, Cd and Cr. This study suggests that sea salts, earth crust and anthropogenic activities such as motor vehicles were the main sources of dust fall in the study areas.