| Abstract |
The Tentative Standard Method (TSM) for concentrating viruses from drinking water was evaluated for nine viruses using 100-gal tap water volumes experimentally contaminated with about 100 plaque-forming units of virus. The mean recoveries of poliovirus 1, coxsackievirus A9 and B3, echovirus 7, bovine enterovirus 1, Minute Virus of Mice (parvovirus), reovirus 3, adenovirus 5 and simian adenovirus 11 were 22, 25, 2.5, 6.7, 22, 5.0, 1, 1 and 1%, respectively. Although the recovery differences for the five enteroviruses suggested variable TSM effectiveness depending upon virus type, subsequent simultaneous testing showed no significant recovery differences. TSM recoveries of enteroviruses obtained from raw sewage and seeded into 100-gal volumes of tap water averaged only 3.9% which was approximately the same as poliovirus recoveries during the same time period. Enterovirus recoveries showed marked seasonal variations that may be related to water quality changes. Low virus recoveries by the TSM were partly due to virus inactivation by the pH 11.5 glycine-NaOH used for elution. Virus recoveries with negatively charged filters could be markedly improved by procedural modifications: (1) use of aluminum or magnesium chloride to enhance adsorption, (2) use of less alkaline glycine or beef extract with and without EDTA for elution, and (3) recirculation of the eluent through the adsorbent filters. With the exception of MVM, viruses in beef extract eluents could be efficiently reconcentrated by organic flocculation. Improved virus recoveries were also obtained with adsorbent filters that are more electropositive than TSM filters. |
