VIRUS TRANSPORT EXPERIMENTS IN A SANDY AQUIFER M. YAVUZ CORAPCIOGLU 1,∗ , JASON R. VOGEL 2 , CLYDE L. MUNSTER 3 , SURESH D. PILLAI 4 , SCOT DOWD 5 and SOOKYUN WANG 6 1 Dept. of Civil Eng., Texas A&M Univ., College Station, TX 77843, USA; 2 Department of Biosystems and Agricultural Eng., Oklahoma State University, Stillwater, OK 74078, USA; 3 Department of Biological and Agricultural Eng., Texas A&M University, College Station, TX 77843, USA; 4 Department of Poultry Sciences, Texas A&M University, College Station, TX 77843, USA; 5 Department of Microbiology and Immunology, University of Arizona, Tucson, AZ 85721, USA; 6 Department of Env. Exploration, Pukyoung National Univ., 559-1 Daeyon-dong, Nam-gu, Busan 608-737, Korea ( ∗ author for correspondence, e-mail: yavuz@neo.tamu.edu) (Received 24 November 2004; accepted 8 July 2005) Abstract. The occurrence of human enteric viruses in ground water has been well documented in the literature. Bacteriophages such as MS-2 and PRD1 have properties similar to pathogenic human viruses suggesting that bacteriophages can be used as proxies for virus transport. The objective of this study is to investigate a “worst case scenario” for virus transport in a ground water aquifer, i.e., sand and gravel aquifer under a forced-gradient, by using bacteriophages. Field studies have been conducted to trace large-scale (34 m) and small-scale (10 m) virus transport under natural- and forced-gradients through a sand and gravel aquifer at a ground water research site at the Texas A&M University. Virus transport was monitored under natural and forced-gradient conditions using MS-2 and PRD-1 as virus tracers and bromide as a conservative tracer. Results indicate virus and bromide transport to down-gradient monitoring wells in both the large- and small- scale field tests. During the tests conducted, MS-2 transport appears to exhibit little longitudinal dispersion, showing a narrow peak at the well nest 34 m down-gradient in 13 days which is 20 days before the bromide breakthroughs, indicating that bacteriophage transport through the aquifer was mainly by advective flow. Differences in tracer transport can be attributed to the heterogeneity of the sand and gravel aquifer at the site, different injection methods, different sampling methods, and different tracer properties. Heterogeneity of the aquifer would cause virus transport through preferential flow paths. Keywords: ground water flow, virus transport, septic tanks, aquifer contamination, field experiments Introduction Virus contamination of ground water can be caused by failure of septic tanks, sewer lines, or waste disposal sites. This threat of ground water contamination has led to increased efforts to study the transport of viruses through the ground water (Corap- cioglu and Haridas, 1985; Kinoshita et al., 1993; Maguire et al., 1993; Powelson et al., 1993; Bales et al., 1995; Schijen and Simunek, 2002). Previous studies have shown that bacteriophages have soil adsorption and overall survival kinetics which are similar to pathogenic human viruses suggesting that bacteriophages can be used as proxies for virus transport (Gerba, 1984). Water, Air, and Soil Pollution (2006) 169: 47–65 C  Springer 2006