Abdul Qayyum Siddiqui - Research Institute of Natural Resources and Environment, KACST, P.O. Box 6086, Riyadh 11442 Saudi Arabia
Yousef S. Al-Hafedh - King Abdulaziz City for Science and Technology
Ahmed H. Al-Harbi - King Abdulaziz City for Science and Technology
Seikh A. Ali - Research Institute of Natural Resources and Environment, KACST, P.O. Box 6086, Riyadh 11442 Saudi Arabia