Column experiments to study nonlinear removal of bacteriophages by passage through saturated dune sand J.F. Schijven a, * , S.M. Hassanizadeh b,1 , H.A.M. de Bruin a,2 a National Institute of Public Health and the Environment, Microbiological Laboratory for Health Protection, P.O. Box 1, 3720 BA Bilthoven, The Netherlands b Delft University of Technology, Faculty of Civil Engineering and Geosciences, P.O. Box 504, 2600 GA Delft, The Netherlands Received 2 March 2001; received in revised form 15 February 2002; accepted 12 April 2002 Abstract In a recent field study on dune recharge, bacteriophages MS2 and PRD1 were found to be removed 3 log 10 over the first 2.4 m and only 5 log 10 over the next 27 m. To understand the causes of this nonlinear removal, column experiments were carried out under conditions similar to the field: same recharge water, temperature (5 F 3 jC) and pore water velocity (1.5 m day  1 ). Soil samples were taken along a streamline between the recharge canal and the first monitoring well. Bacteriophage fX174 was included for comparison. The high initial removal in the field was found not to be due to heterogeneity of phage suspensions but to soil heterogeneity. Phage removal rates correlated strongly positively with soil organic carbon content, and relatively strongly positively with silt content and the presence of ferric oxyhydroxides. Soil organic carbon content, silt content and the presence of ferric oxyhydroxides were found to decrease exponentially with travel distance. Removal rates of fX174 were found to be 3–10 times higher than those of MS2 and PRD1 due to the lower electrostatic repulsion that the less negatively charged fX174 experiences. It is suggested that the high initial removal in the field is due to the presence of favorable sites for attachment formed by ferric oxyhydroxides that decrease exponentially with travel distance. Similar removal rates may be found at both laboratory and 0169-7722/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII:S0169-7722(02)00040-2 * Corresponding author. Tel.: +31-30-274-2994; fax: +31-30-274-4434. E-mail addresses: Jack.Schijven@rivm.nl (J.F. Schijven), Majid.Hassanizadeh@ct.tudelft.nl (S.M. Hassanizadeh), Ria.de.Bruin@rivm.nl (H.A.M. de Bruin). 1 Tel.: + 31-15-278-7346. 2 Tel.: + 31-30-274-3929. www.elsevier.com/locate/jconhyd Journal of Contaminant Hydrology 58 (2002) 243 – 259