Indicatory role of coliphages in relation to contamination of drinking water by enteroviruses

It has been found out that a coli-phage is a more reliable indirect indicator of viral pollution of drinking water that the existing indirect bacterial indicators. Coli-phages concentration in drinking water on the level of single PFU/1 is evidence of disturbances in the barrier function of water-treatment facilities with respect to viral microflora and of the possible epidemic danger of water with respect to viral infection. The absence of coli-phages in I 1 of water sample should be considered the standard level of coli-phages of drinking water.     

Somatic coliphages and bacterial indicators of bathing water quality in the beaches of Gipuzkoa, Spain

Monitoring the quality of the bathing waters of Gipuzkoa (the Basque Country, Spain) makes it possible to assess the suitability of its 15 beaches for bathing throughout each season. In 1998, the parameters E. coli, somatic coliphages (SOMCPH) and F-specific RNA bacteriophages (FRNAPH) were incorporated into the bathing water quality monitoring system. This enabled the study of the link between bacterial and viral indicators as well as the analysis of the ratios between both types of indicators in waters with different levels of pollution. Although bacterial indicators (total coliforms (TC) and faecal coliforms (FC)) and enterococci showed a strong correlation between them, the correlations between the viral indicators and between the viral and bacterial indicators were weaker, though significant in all cases. The ratio between SOMCPH and E. coli indicates that at low levels of bacterial pollution (E coli <100 MPN/100 ml) SOMCPH outnumber E coli. In contrast, at higher levels of pollution (E coli >100 MPN/100 ml), SOMCPH numbers are lower than those of E-coli. The data reveal the presence of viral indicators in waters classified as suitable for bathing by the European Directive and alert us to their suitability.     

Somatic coliphages and bacterial indicators of bathing water quality in the beaches of Gipuzkoa, Spain

Monitoring the quality of the bathing waters of Gipuzkoa (the Basque Country, Spain) makes it possible to assess the suitability of its 15 beaches for bathing throughout each season. In 1998, the parameters E. coli, somatic coliphages (SOMCPH) and F-specific RNA bacteriophages (FRNAPH) were incorporated into the bathing water quality monitoring system. This enabled the study of the link between bacterial and viral indicators as well as the analysis of the ratios between both types of indicators in waters with different levels of pollution. Although bacterial indicators (total coliforms (TC) and faecal coliforms (FC)) and enterococci showed a strong correlation between them, the correlations between the viral indicators and between the viral and bacterial indicators were weaker, though significant in all cases. The ratio between SOMCPH and E. coli indicates that at low levels of bacterial pollution (E coli <100 MPN/100 ml) SOMCPH outnumber E coli. In contrast, at higher levels of pollution (E coli >100 MPN/100 ml), SOMCPH numbers are lower than those of E-coli. The data reveal the presence of viral indicators in waters classified as suitable for bathing by the European Directive and alert us to their suitability.     

The emission potential of different land use patterns for the occurrence of coliphages in surface water

Different land use patterns were investigated for their potential as non-point sources of coliphage emissions into surface waters. Water samples were taken regularly at five locations in the upper reaches of the river Swist, Germany. Samples of surface and subsurface run-off were taken within the same catchment area after rainfall events using a newly developed device that made it possible to collect current concentrations of the effluent compounds. The water quality was examined for the occurrence of somatic coliphages and F(+)-specific RNA-bacteriophages as well as for various bacteria over the period of a hydrological year. The potential of various bacteria as indicators for the occurrence of phages was evaluated using statistical correlations. The load of coliphages varied depending on the land use type, but it did not differ as much as the bacterial parameters. River sections in intensively used areas turned out to be more contaminated than in less intensively used regions. The concentrations of phages from surface and subsurface run-off in most samples were quite low for all land use types and did not show conspicuous variations of surface and subsurface run-off within one land use type. Therefore, high concentrations of phages in river water cannot be explained only by non-point effluent from open ground. Following consideration of the statistical results, conventional indicator bacteria seem not to be reliable indicator organisms for coliphages and subsequently for human pathogen viruses. The detected concentrations of coliphages in several water samples of river sections surrounded by intensively used areas underpin an existing health risk in the use of river water for e.g. recreational activities or irrigation.     

A comparison of the survival of F+RNA and F+DNA coliphages in lake water microcosms

The survival of seven F+RNA phages (MS2 Group I ATCC type strain, two Group I environmental isolates, a Group II environmental isolate, a Group III environmental isolate, and two Group IV environmental isolates) and six F+DNA phages (M13, fd, f1, and ZJ/2 ATCC type strains, and two environmental isolates) were examined in microcosms using a surface drinking water source. Phages were spiked into replicate aliquots of a source water at about 20,000 pfu/ml. Replicate spikes were incubated at 4 and 20 degrees C and monitored for 110 days. At 4 degrees C, Groups I and II F+ RNA phages were detectable through 110 days, with reductions of about 1 and 3 log10, respectively. The Group III F+RNA phage demonstrated 5 log10 reduction after 3 weeks, and the Group IV F+RNA phages were reduced to detection limits (5 log10 reduction) within 10 days. Of the F+DNA phages, all four type strains were detectable with about 2.5 log10 reduction after 110 days at 4 degrees C. The F+DNA environmental isolates were detectable with about a 4 log10 reduction after 110 days at 4 degrees C. All phages demonstrated faster decay at 20 degrees C. These results suggest that differences in F+ phage survival may influence their prevalence in environmental waters and the ability to attribute their prevalence to specific human and animal sources of faecal contamination.     

The economic expediency of digital fluorography

The paper shows the advantages of digital versus routine film fluorography, which allows a user to make a choice of the type of an apparatus for fluorographic examination. The expenses of a fluorographic room on developing equipment and expendable materials for different types of the room's equipment. It gives the cost and specific features of the use of current film and digital fluorographs and the data on the cost of an examination using film and digital fluorography in case of the most cost-effective fluorographic systems.     

水中臭氧的快速测定

建立了水中臭氧的ＫＩ－硫酸－４－氨基－Ｎ,Ｎ－二乙基苯胺（ＤＰＤ）分光光度测定法。此方法是在ｐＨ３．５条例上,根据臭氧与碘化钾的定量反应：Ｏ３＋２Ｉ＾－＋２Ｈ＾＋→Ｏ２＋Ｉ２＋Ｈ２Ｏ,生成的Ｉ２与ＤＰＤＰ反应显粉红色,在５１０ｎｍ处用分光光度计测定,直接测定的线型范围为０～１．００ｍｇ／Ｌ,最低检测浓度为０．０１ｍｇ／Ｌ,相对标准偏差为１．２％～２．７％（ｎ＝１０）,回收率在９８．６％～１０６．６     

Prevalence of protozoa, viruses, coliphages and indicator bacteria in groundwater and river water in the Kathmandu Valley, Nepal

Limited information is available on the prevalence of waterborne pathogens in aquatic environments in developing countries. In this study, water samples were collected from nine shallow wells and a river in the Kathmandu Valley, Nepal, during the rainy season in 2009 and were subjected to detection of waterborne protozoa, viruses and coliphages using a recently developed method for simultaneous concentration of protozoa and viruses in water. Escherichia coli and total coliforms were also tested as indicator bacteria. At least one type of the five pathogens tested (Cryptosporidium, Giardia, human adenoviruses, and noroviruses of genogroups I and II) was detected in five groundwater samples (56%) (1000 ml each) from shallow wells. Compared with groundwater samples, the pathogens were more abundant in the river water sample (100 ml); the concentrations of Cryptosporidium and Giardia were 140 oocysts/l and 8500 cysts/l, respectively, and the mean threshold cycle (Ct) values in real-time RT-PCR were 34.3, 36.8 and 34.0 for human adenoviruses and noroviruses of genogroups I and II, respectively. Genotyping of F-RNA coliphages by real-time RT-PCR was successfully used to differentiate human and animal faecal contamination in the samples. Moreover, for the groundwater samples, protozoa and viruses were detected only in E. coli-positive samples, suggesting that E. coli may be an appropriate indicator of pathogen contamination of valley groundwater.     

Comparative study of enteric viruses, coliphages and indicator bacteria for evaluating water quality in a tropical high-altitude system

Background  

Bacteria used as indicators for pathogenic microorganisms in water are not considered adequate as enteric virus indicators. Surface water from a tropical high-altitude system located in Mexico City that receives rainwater, treated and non-treated wastewater used for irrigation, and groundwater used for drinking, was studied.