Transport and recovery of bacteriophage PRD1 in a sand and gravel aquifer: Effect of sewage-derived organic matter

To test the effects of sewage-derived organic matter on virus attachment, 32P-labeled bacteriophage PRD1, linear alkylbenzene sulfonates (LAS), and tracers were injected into sewage-contaminated (suboxic, elevated organic matter) and uncontaminated (oxic, low organic matter) zones of an iron oxide-coated quartz sand and gravel aquifer on Cape Cod, MA. In the uncontaminated zone, 83% of the PRD1 were attenuated over the first meter of transport by attachment to aquifer grains. In the contaminated zone, 42% of the PRD1 were attenuated over the first meter of transport. Sewage-derived organic matter contributed to the difference in PRD1 attenuation by blocking attachment sites in the contaminated zone. At greater distances down gradient (to a total transport distance of 3.6 m), a near-constant amount of PRD1 continued to break through, suggesting that aquifer grain heterogeneities allowed a small amount of reversible attachment. Injection of an LAS mixture (25 mg L-1), a common sewage constituent, remobilized 87% of the attached PRD1 in the contaminated zone, but only 2.2% in the uncontaminated zone. LAS adsorption promoted virus recovery in the contaminated zone by altering the PRD1-surface interactions; however, the amount of LAS adsorbed was not sufficient to promote release of the attached PRD1 in the uncontaminated zone.