Characteristics and Sources of Organic Matter in Desert Sand Samples from the Riyadh and Al-Qasim Areas of Saudi Arabia: Preliminary Results PDF

Keywords

Desert sand, Organic contents, sources and characteristics, Saudi Arabia, Aliphatic, n-alkanes, sterane biomarkers, sterols, n-alkanones

Abstract

Sand samples from the Riyadh and Al-Qasim areas were collected, extracted with a mixture of dichloromethane and methanol (3:1, v:v), and analyzed by gas chromatography-mass spectrometry (GC-MS) in order to characterize the contents and sources of their organic compounds. The major components of the total extracts were straight chain aliphatic compounds from vegetation waxes, fossil fuel combustion, and anthropogenic and agricultural activities. The results showed that anthropogenic inputs had a significant contribution to the organic content of sands near populated areas. This urban component consisted mainly of n-alkanes, n-alkanoic acids, n-alkyl amides, hopane and sterane biomarkers, and pesticide residues. Organic inputs from natural sources included n-alkanes, n-alkanoic acids, n-alkanols, methyl alkanoates, sterols, and n-alkanones.