Forces dictating colloidal interactions between viruses and soil

The fate and transport of viruses in soil and aquatic environments were stu died with respect to the different forces involved in the process of sorpti on of these viruses on soil particles. In accordance with the classical DLV O theory, we have calculated the repulsive electrostatic forces and the att ractive van der Waals forces. Bacteriophages have been used as model sorbat es, while different clays have been used as model sorbents. The equations u sed for the determination of the change in free energy for the process (Del ta G) takes into consideration the roughness of the sorbent surfaces. Resul ts indicate that attractive van der Waals forces predominate the process of sorption of the selected bacteriophages on clays. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.