Assessment of drinking water quality using indicator bacteria and bacteriophages.
Bacterial indicators and bacteriophages suggested as potential indicators of water quality were determined by public laboratories in water from springs, household water wells, and rural and metropolitan water supplies in north-eastern Spain. Indicator bacteria were detected more frequently than bacteriophages in springs, household water wells and rural water supplies. In contrast, positive bacteriophage detections were more numerous than those of bacteria in metropolitan water supplies. Most of the metropolitan water supply samples containing indicators had concentrations of chlorine below 0.1 mg l(-1), their indicator loads resembling more closely those of rural water supplies than any other samples taken from metropolitan water supplies. The number of samples from metropolitan water supplies containing more than 0.1 mg l(-1) of chlorine that contained phages clearly outnumbered those containing indicator bacteria. Some association was observed between rainfall and the presence of indicators. Sediments from service reservoirs and water from dead ends in the distribution network of one of the metropolitan water supplies were also tested. Bacterial indicators and phages were detected in a higher percentage than in samples of tap water from the same network. Additionally, indicator bacteria were detected more frequently than bacteriophages in sediments of service reservoirs and water from dead end samples. We conclude that naturally occurring indicator bacteria and bacteriophages respond differently to chlorination and behave differently in drinking water distribution networks. Moreover, this study has shown that testing for the three groups of phages in routine laboratories is easy to implement and feasible without the requirement for additional material resources for the laboratories.
Méndez
Javier
J
Departamento de Microbiología, Universidad de Barcelona, Avda Diagonal 645, 08028 Barcelona, Spain.
Audicana
Ana
A
Cancer
Mercedes
M
Isern
Anna
A
Llaneza
Julian
J
Moreno
Belén
B
Navarro
Mercedes
M
Tarancón
M Lluisa
ML
Valero
Fernando
F
Ribas
Ferran
F
Jofre
Juan
J
Lucena
Francisco
F
D001435:Bacteriophages / Q000302:isolation & purification*; D002713:Chlorine / Q000008:administration & dosage; D004755:Enterobacteriaceae / Q000302:isolation & purification; D016983:Enterococcus / Q000302:isolation & purification; D004784:Environmental Monitoring / Q000379:methods*; D004926:Escherichia coli / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D006801:Humans; D011891:Rain; D018570:Risk Assessment / Q000379:methods; D012423:Rural Health; D013030:Spain; D014504:Urban Health; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods; D014881:Water Supply / Q000032:analysis* / Q000592:standards*
D002713:Chlorine