Recreational water quality control in Mississippi, USA: bacteriological assessment in the Pearl River and Ross Barnett reservoir

We assessed the bacteriological water quality in the Pearl River and Ross Barnett reservoir, a major source of public raw water for the city of Jackson, Mississippi, USA and an important site for recreational activities for local residents and visitors. Infectious diseases caused by pathogenic bacteria are the most common and widespread health risks associated with such water contact activities as bathing, canoeing, and swimming in recreational waters. Water samples collected twice monthly from April 2004 to April 2005 from five different sites of the Pearl river/Ross Barnett reservoir were tested for heterotrophic bacteria, total coliforms, fecal coliforms, and enterococci using membrane filtration technique. Physicochemical parameters (temperature, pH, turbidity, dissolved oxygen, conductivity) were also analyzed using standard methods. The respective mean concentrations of bacteria in water samples were 8.9 x 10(4) +/- 7.4 x 10(4) colony forming units (CFU) 100 mL(-1), 3.0 x 10(3) +/- 4.1 x 10(3) CFU 100 mL(-1), 2.3 x 10(2) +/- 5.4 x 10(2) CFU 100 mL(-1), and 2.3 x 10(2) +/- 4.8 x 10(2) CFU 100 mL(-1) for heterotrophic bacteria, total coliforms, enterococci, and fecal coliforms. The mean values of the physical and chemical parameters were at acceptable levels. Bacterial densities, however, significantly exceeded federal/state guidelines, raising public health concerns. Hence, control strategies should be developed and implemented to prevent further bacterial contamination of Pearl River-Ross Barnett reservoir water resource system.     

Probleme bei der Anwendung der DIN EN 12780 zum Nachweis von Pseudomonas aeruginosa aus Schwimmteichen und Oberflächengewässern

Pseudomonas aeruginosa (P. aeruginosa) is a relevant pathogen to bathers and, therefore, water from natural swimming pools is analyzed for its presence. P. aeruginosa can be detected regularly in surface waters. Currently the methods described in DIN EN 12780 are recommended for the quantitative analysis of water from natural swimming pools, although this standard was developed for bottled water. The present study examines whether the recommendation is satisfactory. In 93 water samples from five natural swimming pools (Naturschwimmteiche), 3226 presumptive P. aeruginosa colonies were detected. Of the 3226 colonies, 101 were directly confirmed due to their formation of pyocyanin. From the remaining 3125 colonies, 349 representative samples were isolated and examined further. Using the criteria of DIN EN 12780 fluorescense and ammonia formation from acetamide, another 45 colonies were considered to be P. aeruginosa. 71 % (32) of these 45 non-pyocyanin-forming strains could not be confirmed by the APINE system. None of the 32 strains grew at 42°C, which is a characteristic feature of P. aeruginosa as mentioned in a note of DIN EN 12780. In 20 of the original samples, P. aeruginosa numbers exceeded the recommended limit value of 10/100 ml. Eleven cases (55 %) were caused by P. aeruginosa, which were not confirmed taxonomically. Due to insufficient selectivity, the method according to DIN EN 12780 is not applicable for the testing of surface waters and water from natural swimming pools. The high number of false positive results for P. aeruginosa questions the standard even further. It is suggested that for surface water samples growth of P. aeruginosa at 42 °C has to be checked as an additional confirmation characteristics of P. aeruginosa until a reliable standard is published.     

Spatial Distribution of Diarrhoea and Microbial Quality of Domestic Water during an Outbreak of Diarrhoea in the Tshikuwi Community in Venda, South Africa

Total microbial quality assessment and geographical information system were used for evaluating the quality of water and the spatial distribution of diarrhoea cases in Tshikuwi, a rural community in South Africa, during an outbreak of diarrhoea. The water-abstraction points included two groundwater storage tanks, namely Tank 1 and Tank 2 and the Khandanama river. Indicator microbial counts for total coliforms, faecal coliforms, enterococci, and heterotrophic bacteria exceeded the limit for no risk as stipulated by the South African water-quality guidelines for domestic use for Tank 1 and the Khandanama river. Vibrio, Salmonella, and Shigella species were prevalent in the Khandanama river. The spatial distribution of diarrhoea cases showed a hot-spot of diarrhoea cases close to Tank 1 and the Khandanama river. Results of chi-square analysis showed that the proportion of infection from each water source was different or that infection depends on the type of water source (α=0.05). The demonstrated spatial clustering of diarrhoea cases might have been influenced by the poor microbial quality of water used from Tank 1 and the Khandanama river. The results further highlight the urgent need of water-treatment facilities and monitoring of water quality in rural communities of South Africa.Key words: Diarrhoea, Disease outbreaks, Spatial distribution, Water pollution, Water supply, South Africa     

Microbial quality of drinking water from microfiltered water dispensers

A comparison was made between the microbial quality of drinking water obtained from Microfiltered Water Dispensers (MWDs) and that of municipal tap water. A total of 233 water samples were analyzed. Escherichia coli (EC), enterococci (ENT), total coliforms (TC), Staphylococcus aureus, Pseudomonas aeruginosa and heterotrophic plate count (HPC) at 22 °C and 37 °C were enumerated. In addition, information was collected about the principal structural and functional characteristics of each MWD in order to study the various factors that might influence the microbial quality of the water.EC and ENT were not detected in any of the samples. TC were never detected in the tap water but were found in 5 samples taken from 5 different MWDs. S. aureus was found in a single sample of microfiltered water. P. aeruginosa was found more frequently and at higher concentrations in the samples collected from MWDs. The mean HPCs at 22 °C and 37 °C were significantly higher in microfiltered water samples compared to those of the tap water.In conclusion, the use of MWDs may increase the number of bacteria originally present in tap water. It is therefore important to monitor the quality of the dispensed water over time, especially if it is destined for vulnerable users.     

High level of recovery of fungi from water and dialysate in haemodialysis units

The counts of yeasts and filamentous fungi were investigated in the municipal water supplies of haemodialysis centres, in the treated water and the dialysate from all 85 haemodialysis units in Greece, in order to estimate their occurrence, their correlation with contamination indicator bacteria and other influencing factors. Filamentous fungi and yeasts were isolated from 69 (81.2%) and from three (3.5%) feed water samples, from 74 (87.1%) and seven (8.2%) treated water samples and from 66 (77.7%) and 11 (12.9%) dialysate samples respectively. Aspergillus spp and Penicillium spp were the most frequent moulds, while Candida spp were the prevailing yeasts. The occurrence of yeasts was significantly higher in dialysate than in tap water samples. Counts of filamentous fungi in all 255 samples were significantly correlated with the counts of total heterotrophic bacteria and enterococci, whereas the counts of yeasts were correlated with faecal coliforms, total heterotrophic bacteria, as well as enterococci, Pseudomonas spp and total coliforms, while no correlation was detected with the age of either haemodialysis units, the age of water treatment system, the number of artificial kidney machines or the components of the water purification system. High recovery of fungi from haemodialysis aqueous environments implies a potential risk for haemodialysis patients and indicates the need for continuous maintenance and monitoring.     

Health effects of marine bathing in New Zealand

Prospective epidemiological studies on the possible health effects from sea bathing were carried out at seven popular New Zealand bathing beaches over the 1995 summer. The association of gastrointestinal/ respiratory symptoms or other infections with human or animal faecal contamination of the beach water was examined. Beach users were interviewed at the beach and then followed up within 5 days to ascertain any illness symptoms. On each of the 107 interview days multiple samples of the beach water were examined for three faecal indicators (faecal coliforms, E. coli , enterococci). Of the usable responses, 2307 users did not enter the water; 1577 did. Log-linear modelling showed that enterococci was most strongly and consistently associated with illness risk for the exposed groups, particularly for respiratory illness among paddlers and long-duration swimmers. Crude risk differences for these two groups were 7 and 33 per 1000 individuals, rising to 62 and 87 per 1000 individuals for the highest enterococci quartile. No substantial differences in illness risks were found between the human and animal waste impacted beaches, though both were markedly different from the control beaches. The results are being used to develop recommendations for sampling design and use of single-sample maxima in new bathing-water guidelines.     

Microbiological and chemical quality of sludges from domestic wastewater plants

Digested sludge samples from domestic wastewater treatment plants located in Northern Italy were tested as far as the presence of viruses (enteric viruses and coliphages), bacteria (faecal coliforms, salmonella) and helminth eggs is concerned. Heavy metals were also analysed. Escherichia coli bacteriophages and faecal coliforms were isolated from all samples, while salmonellae and helminth eggs were isolated only from four and three out of 27 total samples, respectively. The 66% of sludge samples, 46 and 82% of aerobic and anaerobic digested sludges respectively, showed the presence of enteric viruses (enteroviruses and reoviruses). The virus concentrations ranged from 0.6 to 123 MPNCU/g. Results of this study suggest that significant concentrations of pathogens such as enteric viruses can be present in digested sludge, which showed compliance with Italian legislation. As suggested by other authors, there is the need for surveillance and reference indications both in EU (European Union) and Italian regulations concerning the use of sludge in agriculture.     

The microbiological quality of potable water on board ships docking in the UK and the Channel Islands: an association of Port Health Authorities and Health Protection Agency Study

Providing safe potable water onboard vessels presents particular challenges and contamination can occur directly from source waters as well as during loading, storage and distribution. Between May and October 2005, 950 potable water samples were collected from 342 ships docking at ports. Comparison with Guidelines found 9% of samples contained coliforms, Escherichia coli or enterococci and 2.8% had faecal indicators (E. coli or enterococci). Action levels of aerobic colony count (ACC) bacteria were detected in 20% (22°C) and 21.5% (37°C) of samples. ACC results from one-off sampling are not informative as this does not enable port health authorities to monitor ACC trends. They should be removed as a routine criterion for remedial action and vessels should adopt the WHO Water Safety Plan approach, whilst continuing to monitor water quality with public health-based indicators (e.g. chlorine residual, coliforms, E. coli and enterococci). Logistic regression analyses identified practices associated with water quality. Practices protective against coliforms, E. coli or enterococci in potable supplies were: good hose hygiene, processing water onboard, maintaining free chlorine residual at 0.2 mg/L. This emphasizes the importance of good hygiene during potable water loading and maintaining adequate disinfection of supplies onboard.     

The microbiological quality of potable water on board ships docking in the UK and the Channel Islands: an association of Port Health Authorities and Health Protection Agency Study

Providing safe potable water onboard vessels presents particular challenges and contamination can occur directly from source waters as well as during loading, storage and distribution. Between May and October 2005, 950 potable water samples were collected from 342 ships docking at ports. Comparison with Guidelines found 9% of samples contained coliforms, Escherichia coli or enterococci and 2.8% had faecal indicators (E. coli or enterococci). Action levels of aerobic colony count (ACC) bacteria were detected in 20% (22 degrees C) and 21.5% (37 degrees C) of samples. ACC results from one-off sampling are not informative as this does not enable port health authorities to monitor ACC trends. They should be removed as a routine criterion for remedial action and vessels should adopt the WHO Water Safety Plan approach, whilst continuing to monitor water quality with public health-based indicators (e.g. chlorine residual, coliforms, E. coli and enterococci). Logistic regression analyses identified practices associated with water quality. Practices protective against coliforms, E. coli or enterococci in potable supplies were: good hose hygiene, processing water onboard, maintaining free chlorine residual at >or=0.2 mg/L. This emphasizes the importance of good hygiene during potable water loading and maintaining adequate disinfection of supplies onboard.     

An integrated appraisement of multiple faecal indicator bacteria and sterols in the detection of sewage contamination in subtropical tidal creeks

The quality of water bodies has been regulated by national environmental agencies and based on faecal indicator bacteria, such as thermotolerant coliforms Escherichia coli and Enterococcus sp. Additionally, faecal sterols (mainly coprostanol) have been used to corroborate sewage discharge in marine environments. In this study, faecal material input was evaluated in two sampling campaigns in transects of two tidal creeks using bacterial and chemical indicators to both compare and establish the water quality in a South Atlantic subtropical estuary. The Itiberê tidal creek (S1) was classified as “contaminated” by faecal material, while the Peças tidal creek (S2) presented variable water quality according to the sampling period and sewage indicators considered in this evaluation. Then, the integrated application of chemical and bacterial indicators was applied for tidal creeks with different sewage contamination levels and under distinct environmental conditions and confirmed that Enterococcus sp. and coprostanol are the most suitable for estuarine environments.     

Diversity of Salmonella spp. and fungi in northern Greek rivers and their correlation to fecal pollution indicators

The prevalence and diversity of Salmonella spp., filamentous fungi, and yeasts and their correlation with fecal pollution indicators (total coliforms, fecal coliforms, enterococci) and total heterotrophic bacteria counts were investigated in 95 water samples from the northern Greek rivers Aliakmon and Axios. Salmonella spp. were isolated in 27.4% of the samples and a total of 19 serotypes were identified. The frequency of Salmonella isolation was higher in the Axios (36.8%) than in the Aliakmon (21.0%) river. Significantly (P<0.001) more Salmonella spp. were recovered during warm (41.4%) than cold (5.4%) months. Salmonella-positive samples showed significantly higher counts of total heterotrophic bacteria and coliforms. Filamentous fungi were isolated from 98.9% and yeasts from 17.9% of the samples with respective mean counts of 2.36 x 10(3) and 1.28 x 10(2)cfu/100mL. Totals of 23 genera of filamentous fungi and 3 genera of yeasts were identified. The most frequent filamentous fungi were Penicillium and Aspergillus, while Candida was the most prevalent yeast. A significant (P<0.001) positive correlation of the fecal pollution indicators was demonstrated only for filamentous fungi. The results of this study indicate that these rivers may be potential pathways for human and other animal contamination with Salmonella spp., filamentous fungi, and yeasts, which contribute to the pollution of marine waters and the surrounding environment.     

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.     

Microbiological quality of muesli samples purchased in retail network

The estimation of microbiological quality of muesli samples was the aim of this investigation. The study included 40 samples which represented various consignments of muesli, produced in 2002 year. Total number of aerobic mesophilic bacteria, yeasts and moulds, and also occurrence of pathogenic bacteria, coliforms and enterococci were determined. The systematic units of muesli fungal flora have been identified. It was stated that microbiological quality of all tested muesli was good. No pathogenic bacteria (Salmonella, Staphylococcus aureus and Bacillus cereus) was detected and also coliforms and enterococci titre was correct (> 0.1 g). A majority of samples characterized low contamination levels of mesophilic aerobic bacteria and fungi, and their total number did not exceed, suitably 10(3) and 10(2) cfu/g. The mesophilic aerobic bacteria were mainly represented by vegetative forms. The average share of these bacteria spores in total number of bacteria received 30%. The Aspergillus sp. and Penicillium sp. were regular elements of muesli fungal flora.     

Faecal pollution of ocean swimming pools and stormwater outlets in eastern Sydney

Abstract: We determined the levels of faecal contamination over a three–year period from 1991 to 1993 at selected ocean swimming pools and stormwater outlets to assess whether these levels represented a threat to public health. Three popular ocean swimming pools and three nearby stormwater outlets located in Sydney's eastern suburbs were included in the analysis. The ocean swimming pools consistently had elevated levels of faecal coliform bacteria; the highest microbe levels were observed in a pool used largely by children. Faecal coliform bacteria counts in the ocean pools at times reach levels likely to be associated with illness in bathers. Stormwater outlets at three locations had reducing counts over the three–year period. An improved system of sampling, testing and risk communication appears to be needed to reduce potential health risks to users of these popular ocean pools. (Aust N Z J Public Health 1997; 21: 567–71)     

Integration of Pseudomonas aeruginosa and Legionella pneumophila in drinking water biofilms grown on domestic plumbing materials

Drinking water biofilms were grown on coupons of plumbing materials, including ethylene-propylene-diene-monomer (EPDM) rubber, silane cross-linked polyethylene (PE-X b), electron-ray cross-linked PE (PE-X c) and copper under constant flow-through of cold tap water. After 14 days, the biofilms were spiked with Pseudomonas aeruginosa, Legionella pneumophila and Enterobacter nimipressuralis (10⁶ cells/mL each). The test bacteria were environmental isolates from contamination events in drinking water systems. After static incubation for 24 h, water flow was resumed and continued for 4 weeks. Total cell count and heterotrophic plate count (HPC) of biofilms were monitored, and P. aeruginosa, L. pneumophila and E. nimipressuralis were quantified, using standard culture-based methods or culture-independent fluorescence in situ hybridization (FISH). After 14 days total cell counts and HPC values were highest on EPDM followed by the plastic materials and copper. P. aeruginosa and L. pneumophila became incorporated into drinking water biofilms and were capable to persist in biofilms on EPDM and PE-X materials for several weeks, while copper biofilms were colonized only by L. pneumophila in low culturable numbers.E. nimipressuralis was not detected in any of the biofilms. Application of the FISH method often yielded orders of magnitude higher levels of P. aeruginosa and L. pneumophila than culture methods. These observations indicate that drinking water biofilms grown under cold water conditions on domestic plumbing materials, especially EPDM and PE-X in the present study, can be a reservoir for P. aeruginosa and L. pneumophila that persist in these habitats mostly in a viable but non-culturable state.     

Patterns of water use and exposure to trihalomethanes among children in Spain

Few studies characterizing trihalomethane (THM) exposure or examining potential health effects were conducted in children. The present study describes patterns of water use in children as a source of THM exposure, and estimates the daily THM uptake and the relative contribution of each pathway of exposure.A cross-sectional population-based study was conducted in children 9-12 years of age in Sabadell, Catalonia, Spain (N=2037). We collected individual information on ingestion, frequency and duration of showering, bathing and swimming, source of drinking water, age, sex and parental education. Chloroform, dibromochloroform, bromodichloroform and bromoform in tap, bottled and swimming pool water were measured. The daily chloroform and brominated THM uptakes were estimated combining environmental levels with individual water activities using algorithms reported in the literature.Among the studied group, 80% of children drank bottled water and 20% regularly attended swimming pools. Mean THM concentration in bottled, tap and chlorinated pool water were, respectively, 0.3, 117 and 92 μg/L. Brominated THM predominated in the tap water (84% of total THM) and chloroform predominated in the swimming pool (84% of total THM). Children attending swimming pools had four times higher THM uptake compared to non-swimmers (p-value<0.05). Showering was the main pathway of exposure for non-swimmers. Girls and children with low parental education had a higher THM uptake (p-value<0.05) as they reported taking longer showers and more frequent baths.In conclusion, total and specific THM uptake varied considerably with the personal water uses among children. As drinking water was mainly bottled and bathing was infrequent, showering and swimming in pools were the main pathways of THM exposure. Specific water uses among children slightly differed by sociodemographic characteristics.     

Are the defined substrate-based methods adequate to determine the microbiological quality of natural recreational waters?

Monitoring the microbiological quality of water used for recreational activities is very important to human public health. Although the sanitary quality of recreational marine waters could be evaluated by standard methods, they are time-consuming and need confirmation. For these reasons, faster and more sensitive methods, such as the defined substrate-based technology, have been developed. In the present work, we have compared the standard method of membrane filtration using Tergitol-TTC agar for total coliforms and Escherichia coli, and Slanetz and Bartley agar for enterococci, and the IDEXX defined substrate technology for these faecal pollution indicators to determine the microbiological quality of natural recreational waters. ISO 17994:2004 standard was used to compare these methods. The IDEXX for total coliforms and E. coli, Colilert^®, showed higher values than those obtained by the standard method. Enterolert^® test, for the enumeration of enterococci, showed lower values when compared with the standard method. It may be concluded that more studies to evaluate the precision and accuracy of the rapid tests are required in order to apply them for routine monitoring of marine and freshwater recreational bathing areas. The main advantages of these methods are that they are more specific, feasible and simpler than the standard methodology.     

Escherichia coli pollution in a Baltic Sea lagoon: A model-based source and spatial risk assessment

Tourism around the Oder (Szczecin) Lagoon, at the southern Baltic coast, has a long tradition, is an important source of income and shall be further developed. Insufficient bathing water quality and frequent beach closings, especially in the Oder river mouth, hamper tourism development. Monitoring data gives only an incomplete picture of Escherichia coli (E. coli) bacteria sources, spatial transport patterns, risks and does neither support an efficient bathing water quality management nor decision making. We apply a 3D ocean model and a Lagrangian particle tracking model to analyse pollution events and to obtain spatial E. coli pollution maps based on scenario simulations. Model results suggests that insufficient sewage treatment in the city of Szczecin is the major source of faecal pollution, even for beaches 20 km downstream. E. coli mortality rate and emission intensity are key parameters for concentration levels downstream. Wind and river discharge play a modifying role. Prevailing southwestern wind conditions cause E. coli transport along the eastern coast and favour high concentration levels at the beaches. Our simulations indicate that beach closings in 2006 would not have been necessary according to the new EU-Bathing Water Quality Directive (2006/7/EC). The implementation of the new directive will, very likely, reduce the number of beach closings, but not the risk for summer tourists. Model results suggest, that a full sewage treatment in Szczecin would allow the establishment of new beaches closer to the city (north of Dabie lake).     

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.