Wadi (W.) Dara granitic rocks are characterized by presence of uranium occurrence in addition to the presence of another radioactive occurrence along trachytic dyke intruded along fault trend. The mineralogical investigation of radioactive samples clarify the presence of mainly zircon minerals associated with uranium, thorium and with minor amount of rare earth elements ;as well as , ferrocolumbite containing patches of the unidentified rich rare earth silicate mineral. Uranium, thorium, Niobium and Titanium elements are completely adsorbed by the three algae (Cystoseira osmundacea, Palmaria elegans and Chondrus Crispus); while zirconium element is only adsorbed by Cystoseira osmundacea and Palmaria elegans.
Sorption capacity of three different algae (Cystoseira osmundacea, Palmaria elegans and Chondrus Crispus were evaluated in the biosorption of uranium and thorium from wadi  dara; in trachyte rock thorium was completely absorbed by Cystoseira osmundacea, Palmaria elegans while in granite rock Cystoseira osmundacea and Chondrus Crispus have the capability to absorb Th completely, in otherwise uranium was absorbed from the granite rock  by Cystoseira osmundacea in a % 91 than the U in trachyte rock by Palmaria elegans in percent 90%.