Aim:  To evaluate the electropositive, alumina nanofibre (NanoCeram) cartridge filter as a primary concentration method for recovering adenovirus, norovirus and male‐specific coliphages from natural seawater. Methods and Results:  Viruses were concentrated from 40 l of natural seawater using a NanoCeram cartridge filter and eluted from the filter either by soaking the filter in eluent or by recirculating the eluent continuously through the filter using a peristaltic pump. The elution solution consisted of 3% beef extract and 0·1 mol l−1 of glycine. The method using a peristaltic pump was more effective in removing the viruses from the filter. High recoveries of norovirus and male‐specific coliphages (>96%) but not adenovirus (<3%) were observed from seawater. High adsorption to the filter was observed for adenovirus and male‐specific coliphages (>98%). The adsorption and recovery of adenovirus and male‐specific coliphages were also determined for fresh finished water and source water. Conclusion:  The NanoCeram cartridge filter was an effective primary concentration method for the concentration of norovirus and male‐specific coliphages from natural seawater, but not for adenovirus, in spite of the high adsorption of adenovirus to the filter. Significance and Impact of the Study:  This study demonstrates that NanoCeram cartridge filter is an effective primary method for concentrating noroviruses and male‐specific coliphages from seawater, thereby simplifying collection and processing of water samples for virus recovery.

Waterborne enteric viruses may pose disease risks to bather health but occurrence of these viruses has been difficult to characterize at recreational beaches. The aim of this study was to evaluate water for human virus occurrence at two Southern California recreational beaches with a history of beach closures. Human enteric viruses (adenovirus and norovirus) and viral indicators (F+ and somatic coliphages) were measured in water samples over a 4-month period from Avalon Beach, Catalina Island (n = 324) and Doheny Beach, Orange County (n = 112). Human viruses were concentrated from 40 L samples and detected by nested reverse transcriptase polymerase chain reaction (PCR). Detection frequencies at Doheny Beach were 25.5% (adenovirus) and 22.3% (norovirus), and at Avalon Beach were 9.3% (adenovirus) and 0.7% (norovirus). Positive associations between adenoviruses and fecal coliforms were observed at Doheny (p = 0.02) and Avalon (p = 0.01) Beaches. Human viruses were present at both beaches at higher frequencies than previously detected in the region, suggesting that the virus detection methods presented here may better measure potential health risks to bathers. These virus recovery, concentration, and molecular detection methods are advancing practices so that analysis of enteric viruses can become more effective and routine for recreational water quality monitoring.

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