Full Description

A single sample concentration and recovery procedure that can be used for bacteria, protozoa,and viruses will greatly improve the ability of water utilities and other agencies to respond tocontamination events. However, it is critical to minimize exposure of sample collectors topotential biological and chemical hazards in contaminated water. Therefore, the objective of thisstudy was to develop a pathogen detection approach comprising inactivation of microorganismsby ultraviolet (UV) light irradiation in a flow through device followed by ultrafiltration (UF) toconcentrate the sample. Small-scale, low-pressure, flow-through UV lamps achieved inactivationlevels of 3-logsub10/sub with a UV dose of 35 mJ/cmsup2/sup for MS-2 compared to 4-logsub10/sub at 140 mJ/cmsup2/sup forB. subtilis spores. Consequently, a dose of 200 mJ/cmsup2/sup was selected as a target that shouldprovide an acceptable level of operator safety in the event of contaminated samples beingcollected. UF involved recirculation of 100 L spiked drinking water samples through 65Khollow-fiber capsules, providing a concentration factor of 133 ¿¿¿¿¿¿¿¿ 1,000. Average recoveryefficiencies were 68% for MS-2, 76% for echovirus 1, 60% for B. subtilis spores, 57% forSalmonella typhimurium, 86% for Cryptosporidium parvum, and 56% for Encephalitozoonintestinalis. Non-UV irradiated concentrates were compatible with all conventional culturingmethods, infectivity assays, and microscopic detection methods. This work demonstrated thefeasibility of inactivating pathogens using a small-scale UV device and simultaneous recovery ofviruses, protozoa, bacteria, and spores from large volumes of drinking water by UF. Currentwork involves integrating the UV and UF units into a single system, assessing the impact of UVirradiation on the ability to detect target pathogens by culture-independent molecular methods,and evaluating whether doses that are high enough to destroy chemical contaminants willinterfere with molecular detection of pathogens. Includes 12 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2005 Number of Pages: 9File Size: 1 file , 310 KB