Abstract
In this present study soil samples were collected from an agriculture area of Zilfi Province of Saudi Arabia approximately 260 km northwest, of the capital city Riyadh. The area of study (Nafud Desert in Zilfi Province) was surveyed during December 2012 collecting 21 samples from 7 places (Al sabla, Almata, Jaway, Alaaga, Magra, Shlwan, and Althuare, by taking 3 samples from each place at the surface, 20 cm and 40 cm depth .The concentrations of some elements such as Si, Na, Mg, Ca, K, Al, P, S, Ti, V, Mn, Fe, Ni, Cu, As, Au, Pb, Cr, Co, Cd and Zn were measured , using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), after sieving and digestion using HNO3, HCL and HF. In most of the samples the elements (Au or Cd), found to have low concentrations while the element S found to be has the high concentrations. The concentrations of toxic trace elements (Ni, Cd and As), were found have values more than back ground concentrations found in the literature of sandstone. The maximum concentrations of the elements: Pb, Zn, Na, Ca and Cd were found at Al sabla region. On the other hand, the maximum concentrations of the elements: As, and V were found in Shlwan region, while the maximum concentration of Cr was found in Alaaga region. Magra region shows maximum concentrations of elements Au, Si, Ti, P, Al, Fe, Mg,and S. High concentration of elements Cu, Mn and K were found in Althuare region, while Ni in Jaway region, and Co in Magra and Althuare regions

Key words: Porous media, mass transfer, magnetic field, non-Newtonian fluid