New methods for the detection of viruses: call for review of drinking water quality guidelines

2001 ◽  
Vol 43 (12) ◽  
pp. 1-8 ◽  
Author(s):  
W.O.K. Grabow ◽  
M.B. Taylor ◽  
J.C. de Villiers
Keyword(s):  
Water Quality ◽  
Cell Culture ◽  
Drinking Water ◽  
Water Samples ◽  
Raw Water ◽  
Water Supplies ◽  
Water Quality Guidelines ◽  
Quality Guidelines ◽  
Treated Drinking Water ◽  
Drinking Water Samples

Drinking water supplies which meet international recommendations for source, treatment and disinfection were analysed. Viruses recovered from 100 L-1,000 L volumes by in-line glass wool filters were inoculated in parallel into four cell culture systems. Cell culture inoculation was used to isolate cytopathogenic viruses, amplify the nucleic acid of non-cytopathogenic viruses and confirm viability of viruses. Over a period of two years, viruses were detected in 23% of 413 drinking water samples and 73% of 224 raw water samples. Cytopathogenic viruses were detected in 6% raw water samples but not in any treated drinking water supplies. Enteroviruses were detected in 17% drinking water samples, adenoviruses in 4% and hepatitis A virus in 3%. In addition to these viruses, astro- and rotaviruses were detected in raw water. All drinking water supplies had heterotrophic plate counts of <100/mL, total and faecal coliform counts of 0/100 mL and negative results in qualitative presence-absence tests for somatic and F-RNA coliphages (500 mL samples). These results call for a revision of water quality guidelines based on indicator organisms and vague reference to the absence of viruses.

Distribution and removal of Giardia and Cryptosporidium in water supplies in Germany

1998 ◽  
Vol 37 (2) ◽  
pp. 9-18 ◽  
Author(s):  
Panagiotis Karanis ◽  
Dirk Schoenen ◽  
H. M. Seitz
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Water Samples ◽  
Wash Water ◽  
Raw Water ◽  
Water Supplies ◽  
Surface Water Treatment ◽  
Water Treatment Plants ◽  
Drinking Water Samples

This study has been conducted, to estimate the distribution of Giardia and Cryptosporidium in German water supplies and the removal efficiency of surface water treatment plants for Giardia and Cryptosporidium by conventional treatment. Water samples from six surface water treatment plants in different parts of Germany were simoultaneously examined for Giardia and Cryptosporidium. Investigations for both parasites were carried out in the period from July 1993 until December 1995. The results confirmed the occurrence of Giardia and Cryptosporidium in surface and raw water, in intermediate steps after treatment, in back wash water, in the first filtrate and in final water. Giardia or Cryptosporidium or both have been found in 76.2% of the investigated raw water sources. The average number of the detected Giardia cysts was 88.2/100 1 (max. 1314/100 1), and the average number of Cryptosporidium oocysts was 116/100 1 (max. 1081/100 1). In the intermediate steps (including flocculation and several steps of filtration), Giardia or Cryptosporidium or both have been found in 33.3% (50/150) of the samples. 14.9% of drinking water samples (7/47) were positive for Giardia (max. 16.8/100 1) and 29.8% (14/47) were positive for Cryptosporidium (max. 20.8/100 1). Overall, Giardia and Cryptosporidium, or both were detected in 38.3% of the drinking water samples. The parasites have been found in nearly all of the investigated backwash water samples. The filtrate of a rapid sand filter was analysed immediately after filter backwashing during the ripening period of the filter. Good elimination results were obtained by optimizing relevant water treatment process, but a low flocculant dose following sudden variation in the raw water quality, causes a breakthrough of Cryptosporidium into the treated water. Although water treatment technologies are effective to remove Giardia and Cryptosporidium, the results clearly show that Giardia and Cryptosporidium evade the filter barries in the absence of visible treatment deficiencies and low turbitidy level, and contaminate final water.

scholarly journals First investigations into the prevalence of Cryptosporidium and Giardia spp. in Hungarian drinking water

2007 ◽  
Vol 5 (4) ◽  
pp. 573-584 ◽  
Author(s):  
J. Plutzer ◽  
M. H. Takó ◽  
K. Márialigeti ◽  
A. Törökné ◽  
P. Karanis
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Raw Water ◽  
Forest Environment ◽  
Water Supplies ◽  
Purification Method ◽  
Cryptosporidium Oocysts ◽  
River Danube ◽  
Drinking Water Samples ◽  
Giardia Cysts

Safe drinking water is a top priority in preventing disease outbreaks and is of general concern to everyone. This study examines the occurrence of Cryptosporidium and Giardia in Hungarian drinking water supplies for the first time. A total of 76 raw and drinking water samples were examined using the U.S. EPA Method 1623. From these 15 of 34 (48.4%) raw water samples tested positive for Giardia and 7 (26.6%) for Cryptosporidium. Twelve of 45 (26.7%) drinking water samples were positive for Giardia and 6 (13.3%) for Cryptosporidium. Overall, Giardia cysts and/or Cryptosporidium oocysts were detected in 48% of the raw water samples and 35% of the drinking water samples. The highest levels in drinking water were found to be 3 oocysts/100 litres of Cryptosporidium and 63.6 cysts/100 litres for Giardia, enough to cause giardiasis. The highest levels in raw water were 1,030 cysts/100 litres for Giardia and 50 oocysts/100 litres for Cryptosporidium and higher oocyst densities were associated with source water receiving effluents from sewage treatment plants or originating from a forest environment. In addition to this monitoring, riverbank filtrated water and raw water from the River Danube in Budapest were monitored in order to ascertain protozoan removal efficiency of riverbank filtration (RBF). A total of 157 samples, including 87 samples from the River Danube and 70 samples post RBF, were examined. Cryptosporidium and Giardia were detected regularly in the river water but never in riverbank filtered water suggesting the effectiveness of RBF as a purification method. The occurrence of Cryptosporidium oocysts and Giardia cysts in the investigated water supplies may require the water utilities and water authorities in Hungary to apply additional monitoring and treatment and/or watershed controls.

Water Quality and Health

1991 ◽  
Vol 23 (1-3) ◽  
pp. 201-209 ◽  
Author(s):  
W. Kreisel
Keyword(s):  
Water Quality ◽  
Developing Countries ◽  
Drinking Water ◽  
Water Supply ◽  
Human Health ◽  
Pollution Control ◽  
Wastewater Reuse ◽  
Water Supplies ◽  
Minimum Quality Standards ◽  
Quality Guidelines

Water quality can affect human health in various ways: through breeding of vectors, presence of pathogenic protozoa, helminths, bacteria and viruses, or through inorganic and organic chemicals. While traditional concern has been with pathogens and gastro-intestinal diseases, chemical pollutants in drinking-water supplies have in many instances reached proportions which affect human health, especially in cases of chronic exposure. Treatment of drinking-water, often grossly inadequate in developing countries, is the last barrier of health protection, but control at source is more effective for pollution control. Several WHO programmes of the International Drinking-Water Supply and Sanitation Decade have stimulated awareness of the importance of water quality in public water supplies. Three main streams have been followed during the eighties: guidelines for drinking-water quality, guidelines for wastewater reuse and the monitoring of freshwater quality. Following massive investments in the community water supply sector to provide people with adequate quantities of drinking-water, it becomes more and more important to also guarantee minimum quality standards. This has been recognized by many water and health authorities in developing countries and, as a result, WHO cooperates with many of them in establishing water quality laboratories and pollution control programmes.

Application of a molecular method for the detection of group A rotaviruses in raw and treated water

2004 ◽  
Vol 50 (1) ◽  
pp. 223-228 ◽  
Author(s):  
W.B. van Zyl ◽  
P.J. Williams ◽  
W.O.K. Grabow ◽  
M.B. Taylor
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Viral Gastroenteritis ◽  
Treated Water ◽  
Source Of Infection ◽  
Drinking Waters ◽  
Group A Rotaviruses ◽  
Group A ◽  
Treated Drinking Water ◽  
Drinking Water Samples

Group A human rotaviruses (HRVs) are the most important aetiological agents of acute viral gastroenteritis in infants and young children in both developing and industrialised countries. Rotaviruses are resistant to many chemical disinfectants and reportedly survive well in treated tapwater and sewage. In this study a group A specific reverse transcriptase-polymerase chain reaction (RT-PCR) followed by a nested-PCR was applied for the detection of HRVs in raw and treated drinking-water samples drawn at a water reclamation plant. For a period of two years (July 2000 to June 2002), borehole, raw and treated drinking-water samples were collected weekly. Viruses were recovered from the water samples using a glass wool adsorption-elution technique followed by secondary concentration using precipitation with polyethylene glycol. In the first year of the study group A HRVs were detected in 11% sewage samples, 8% partially treated waters and 5% final treated drinking waters. The results of the second year of the study showed the presence of group A HRVs in 11% sewage and untreated surface water samples, 15% partially treated water and 6.5% final treated drinking waters. No HRVs were detected in the water samples from the boreholes. The presence of group A HRVs in treated drinking-water samples suggested that this water could be a potential source of infection to consumers. The data also implied that either the water treatment did not remove HRVs or the treated water was contaminated post-treatment.

Treatment of taste and odor causing substances in drinking water

1997 ◽  
Vol 35 (8) ◽  
pp. 29-36 ◽  
Author(s):  
Youngsug Kim ◽  
Yeongho Lee ◽  
Chai S. Gee ◽  
Euiso Choi
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Iodine Number ◽  
Water Samples ◽  
Pilot Plant ◽  
Raw Water ◽  
Process Scheme ◽  
Taste And Odor ◽  
Detectable Concentration ◽  
Removal Efficiencies

To collect fundamental data for the improvement of drinking water quality, focusing on the removal of 2-MIB, Geosmin, IPMP, IBMP and TCA, a total of 20m3/d pilot plant was operated with process schemes of GAC with post-O3(PP-I), and without ozonation(PP-II). Five taste and odor causing substances could be removed to non-detectable concentration with PP-I, but GAC alone was not so effective as PP-I. The larger the EBCT and Iodine Number of GAC column employed, the higher the removal efficiencies expected. The minimum EBCT and Iodine Number were respectively 15 min and 1,000 mg/g of GAC column. Geosmin removal efficiencies ranged 30 to 40% at 15.6 ng/l during conventional process scheme, but 70 to 80% removal was achieved by the PP-I and 60 to 70% by PP-II was achieved. IPMP removal efficiencies were 60 to 80% with GAC only. IBMP and TCA were seldom detected in raw water samples, but TCA was the most difficult to remove of five taste and odor causing substances.

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