An unexpected temporal pattern of coliphage isolation in groundwaters sampled from wells at varied distances from reclaimed water recharge sites

Potable and monitoring wells located in close proximity to a large groundwa ter recharge project which utilizes a blend of surface water and reclaimed wastewater for recharge were tested for coliphage over a period of 6 months to assess the potential for virus migration. During the first 3 months FRN A phage were detected once at a shallow monitoring well. In late summer, an unexpected pulse of phage was detected in all wells, including control sit es, suggesting an ecological phenomenon independent of recharge operations. Cubic and filamentous F-specific coliphage, consistent with the Levivridae and Inoviridae groups, and a noncontractile tailed phage consistent with t he Siphoviridae family were detected. There was no discernible relationship between recharge operations and the pattern of phage populations detected. Phage were detected using a host designated HS12, a variant of KS(pFamp)R (Debartolomeis, J. and Cabelli, V. J. (1991) Evaluation of an Escherichia r oll host strain for enumeration of f male-specific bacteriophages. Appl. En viron. Microbiol, 57, 1301.). During the study it was found that HS12 conta ined a temperate Myoviridae phage; Myoviridae phage were subsequently exclu ded from the results. A total of 26 production wells, including 3 control s ites, were sampled monthly and 6 monitoring wells were sampled every two we eks: Water reclamation plant effluents and river water upstream of effluent discharges were randomly sampled. The concentration and distribution of ph age isolated was quite different in chlorinated effluent compared to river water. The majority of isolates from reclaimed water were filamentous DNA F -specific phage suggesting this group was more resistant to chlorine. Groun dwater samples were analyzed using a novel large volume enrichment techniqu e that proved very sensitive for detecting low concentrations of phage. (C) 1998 Elsevier Science Ltd. All rights reserved.