Influence of Flow Rate on Transport of Bacteriophage in Shale Saprolite

• Published in: Journal of environmental quality Vol. 31; no. 4; pp. 1095 - 1105
• Main Authors: McKay, L.D., Harton, A.D., Wilson, G.V.
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01.07.2002; Crop Science Society of America; American Society of Agronomy
• Subjects: Applied sciences; Bacteria; Bacteriophages; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Exact sciences and technology; Flow rates; Flow velocity; Geological Phenomena; Geology; Groundwaters; Inactivation; Microbial contamination; Natural water pollution; Pollution; Pollution, environment geology; Porosity; Refuse Disposal; Retention; Sewage; Shales; Soil Microbiology; Static Electricity; Subsoils; Surface water; Surface-groundwater relations; Tracers; Water Movements; Water treatment and pollution; United States; North America; Tennessee; America; Microbiology; Shale; Retention; Transport process; Hydrogeology; Levivirus; Pathogenic; Tectiviridae; Leviviridae; Biological contamination; Ground water; Pollutant behavior; Phage MS2; Tectivirus; Virus; Advection; Medium effect; Bromides; Water pollution; Kinetics; Phage PRD1; Phage; Crack; Macroporosity; Tracers
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2002.1095

ABSTRACT The objective of this study was to investigate the influence of flow rate on transport and retention of bacteriophage tracers in a fractured shale saprolite, which is a highly weathered, fine‐grained subsoil that retains much of the fabric of the parent bedrock. Synthetic ground water containing PRD‐1, MS‐2, and bromide was passed through a saturated column of undisturbed shale saprolite at rates ranging from 0.0075 to 0.96 m d−1 First arrival of the bacteriophage tracers in effluent samples in each of the experiments occurred within 0.01 to 0.04 pore volumes (PV) of the start of injection, indicating that bacteriophage were advectively transported mainly through fractures or macropores. Bacteriophage transport velocities, based on first arrival in the effluent, were very similar to fracture flow velocities calculated using the cubic law for flow in a fractured material. For MS‐2, maximum concentration and mass of tracer recovered both increased steadily as flow rate increased. For PRD‐1, these values initially increased, but were nearly constant at flow rates above 0.039 m d−1, indicating that approximately 50% of the observed losses were independent of flow rate. Evaluation of the data indicates that physical straining and electrostatic or hydrophobic attachment to fracture or macropore walls were the dominant retention processes. Inactivation and gravitational settling playing secondary roles, except at the slowest flow rates. The study suggests that microbial contamination from sources such as septic fields and sewage ponds may pose a threat to the quality of ground water and surface water in areas with saprolitic subsoils.