PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Drinking Water”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1977

Pollution indicator bacteria associated with municipal raw and drinking water supplies.

A total of 3819 bacterial cultures isolated from municipal water samples were identified using a combination of Enterotubules and confirmatory media. Frequency distributions for the different genera or groups of bacteria were similar for raw water and drinking water isolations, except for Escherichia organisms which doubled their frequency in raw water. Differences between the membrane filter (MF) and presence-absence (P-A) test with regard to types of organisms isolated were limited to Klebsiella organisms which were preferentially cultured from MF plates. Members of the genus Enterobacter were isolated more than twice as frequently as any of the other coliform genera dealt with in this study. Aeromonas organisms were detected almost as often as such individual genera as Escherichia, Citrobacter, or Klebsiella. Although non-lactose fermenting colonies (false-negatives) of the coliform genera would not be detected by the MF technique, their lack of detection would likely be offset by the Aeromonas colonies (false-positives). At least 25% of the coliform isolates were either anaerogenic or non-lactose fermenters and would therefore go undetected by the most probably number (MPN) technique.

Bacteria↗
PubMed1979

Water drinking provocative test.

Water drinking provocative test was carried out in 28 chronic simple glaucoma and 17 borderline cases of chronic simple glaucoma. These tests were carried out twice on the same patients with an empty stomach and after taking breakfast at an interval of 15 days. It was observed that there was no significant difference in the outcome of the results even when this test was carried out with a full stomach.

Adult↗
PubMed1976

Detection of virus in water: sensitivity of the tentative standard method for drinking water.

The sensitivity of several microporous virus-adsorbent media for reliably detecting low levels of poliovirus from 380 and 1,900 liters of drinking water by use of the tentative standard method was investigated. The virus-adsorbent media tested were (i) nitrocellulose membrane filters, (ii) epoxy-fiber glass-asbestos filters, (iii) yarn-wound fiber glass depth filters, and (iv) epoxy-fiber glass filter tubes. Virus was adsorbed to the filter media at pH 3.5 and eluted with glycine buffer, pH 11.5. The results from 44 samples demonstrated that poliovirus was detected with a 95% reliability at mean virus input levels of 3 to 7 plaque-forming units/380 liters when 1,900 liters of water was sampled. At mean virus input levels of less than 1 to 2 plaque-forming units/380 liters, the detection reliability was 66% in 76 samples when 1,900 liters of water was sampled. No significant difference in virus detection sensitivity was observed among the various virus adsorbent media tested. Overall virus recovery efficiency ranged from 28 to 42%, with a grand average of 35%. Members of the coxsackievirus groups A and B, echovirus, and adenovirus were also detected when 380 and 1,900 liters of water were sampled. These experimental observations attest to the sensitivity of the tentative standard method for detecting low levels of virus in large volumes of drinking water.

Adenoviridae↗
PubMed1979

[The occurrence of salmonellae in drinking water (author's transl)].

A total of 7187 samples of drinking water from different areas of the Lower Saxonian District of Braunschweig was investigated according to regulations of the Trinkwasser-Verordnung during June 1977 and May 1979. The bacteriological results are given in Tab. 1 and 2. Salmonellae were isolated in three samples of drinking water and in one sample of sludge from a municipal pipe of drinking water (see also Tab. 2). Additional experiments confirm that growth of salmonellae and other enterobacteria is possible in that sludge (Fig. 1 and 2). These findings implicate some considerations: E. coli and coliforms are the most important microbial water quality indicators of the Trinkwasser-Verordnung. It is presupposed that, when the indicator density is low (less than 1 per 100 ml) the probability that pathogen are present also will be very low. But the question is how low. The risk factor may be estimated on the base of the E. coli-Salmonella ratio in raw sewage of about 10(6). But this relation lessens already in effluents of sewage treatment plants to 10(3) and it seems to be often 10(2) in inadequately disinfected drinking water. For example, we have found four Salmonella serotypes and 408 E. coli during two years. Therefore, the judgement of the presence of E. coli or coliforms in samples of drinking water must impact highly on the improvement of the water quality by disinfection in future.

Enterobacteriaceae↗
PubMed2026

Occurrence of antibiotic-resistant E. coli and antibiotic resistance genes from culturable bacteria in drinking water sources along the Upper Mahaweli River, Sri Lanka.

Antibiotic-resistant Escherichia coli (AR-E. coli) and antibiotic resistance genes (ARGs) in aquatic environments pose a serious threat to public health. However, their presence in river water in South Asian countries is not well established. The present study investigated AR-E. coli and ARGs from culturable bacteria in drinking water sources from 14 drinking water treatment plants situated along the Upper Mahaweli River, a tropical central hill-country river system in Sri Lanka. A total of 167 E. coli isolates were tested against ten antibiotics using the Kirby-Bauer method, and genomic DNA from culturable bacteria in 45 water samples were screened for 11 ARGs using PCR. Overall, 60.48% E. coli isolates exhibited resistance to at least one antibiotic and multidrug resistance was detected in 27.54%. Highest resistance was for amoxicillin (47.31%), tetracycline (26.95%), and co-trimoxazole (24.55%) and four antibiotics showed seasonal variation. ARGs, dominated by blaTEM (80.0%), tetA (66.67%), and tetM and qnrS (62.22%) were detected in 42.42% PCR assays (n = 210). Multiple antibiotic resistance index varied from 0.00 to 0.80, with 44.91% exceeding the 0.2 threshold value, and the antibiotic resistance index varied from 0.00 to 0.32, with eight above the threshold (≥ 0.2). Hierarchical cluster analysis grouped majority of drinking water sources into the intermediate category while few were categorized under low (Kotagala and Thalawakelle-Galkanda) and high (Haragama, Paradeka, and Nawalapitiya), reflecting the variability of anthropogenic interference. Results highlight the risk associated with AR-E. coli and ARGs from culturable bacteria in one of Sri Lanka's key drinking water sources. Proactive interventions ensuring long-term safety of drinking water sources are urgently needed to safeguard public health.

Sri Lanka↗
PubMed1979

Can drinking water standards be reliably derived from industrial TLVs?

The accuracy of TLV derived drinking water standards is evaluated. When using the identical TLV conversion methodology which Stokinger and Woodward (1) used in deriving the standard for barium in drinking water, standards for arsenic, cadmium, chromium and lead offer 6, 200, 60, and 10 times less protection than the present drinking water standards, respectively. However, using the same methodology, the TLV derived drinking water standard for fluoride offers greater protection than the present standard by a factor of approximately 2. Thus, the use of the TLV conversion factor should be viewed in as one of many lines of potential evidence which should be reviewed in the standard derivation process - but it should not, if at all possible, be considered alone - as in the case of barium.

Arsenic↗
PubMed1975

[Comparative studies on the action of chlorine and ozone on polioviruses in the reprocessing of drinking water in Essen (author's transl)].

The present study was performed in order to evaluate comparatively the inactivation of polio virus type I strains (wild type and attenuated) by means of chlorine and ozone. Polio virus type I was chosen with regard to its epidemiological behaviour and high stability in drinking-water and sewage lines. In view of the lack of propagation techniques, hepatitis viruses A and B, unfortunately, could not be used for these experiments. The experiments were done under laboratory conditions only, and not in the water recovery plant because of hygienic reasons. Defined quantities of disinfectants were examined for their virus-inactivating effect in water without redox-potential (double-distilled water), water with low defined redox-potential (double-distilled water + KOH), previously chlorinated water with a residual chlorine content of 0.03 mg chlorine per liter (tap water) and water with a high redox-potential (well water from the drinking-water plant). Time-course studies were performed, both with chlorine and ozone, in order to evaluate the characteristics of the inactivation procedure. The experimental conditions chosen varied from experiment to experiment to obtain relevant conclusions for the practice. On the basis of our results, and taking into account the quantitative differences in effect, chlorine and ozone principially can be considered equivalent in their action of virus-disinfection. Both, the initial rate and the kinetics of virus disinfection are really identical. Both disinfectants are dependant on the condition of the water (redox-potential, pH etc.) to a great extent in their efficacy. Therefore, a decision of whether or not ozone should substitute for chlorine for the drinking-water supply in Essen cannot be drawn on the basis of virological experiments. This decision, then, depends more or less on other questions - such as relative costs and practicability of the ozonization on a large technical scale. The safety risk and technical reliability of the ozonization process is of particular significance. In the present condition of the Essen reservoir water, a good virus disinfection can be expected already with 1.0 to 1.5 mg ozone/liter (dissolved!); such a concentration guarantees very little residual ozone and, thus, makes then this procedure technically feasible. Continuous checking of the redox-potential and the amount of the ozone added is necessary. With regard to a continuous supply of ozone, the dependence on current supply must be guaranteed. Ozonization of water, probably by the cleavage of humic acid, promotes bacterial recontamination of the drinking-water in the city taps(Stalder und Klosterkötter, 45). Therefore only a combined pre-ozonization with subsequent chlorination would guarantee, both, safety and improvement of the cosmetical conditions of the drinking-water. Such a combination would be feasible with highly reduced amounts of ozone and chlorine.

Chlorine↗
PubMed1979

[Aquatic myxobacteria as indicators in the evaluation of drinking water quality (author's transl))].

Aquatic myxobacteria were shown to be good indicators of surface contamination of drinking water, or water filtered by an inadequate soil profile, both in experiments with sterilized or biologically active soil profiles, resp., and in actual comparison data obtained in practical drinking water analyses. In experimental investigations with artificial profiles, aquatic myxobacteria were retained to a considerably greater degree than E. coli or P. fluorescens due to stronger forces of adhesion. In a number of bacteriological drinking water analyses, this property was confirmed insofar as aquatic myxobacteria could regularly be demonstrated when inspecting hygienically deficient wells or springs. The confirmed presence of E. coli, on the other hand, showed a considerably lesser correlation with the results of on the spot evaluations of hygienic conditions. It must be urgently advised to include the search for aquatic myxobacteria in bacteriological drinking water analyses, since, contrary to the demonstration of E. coli, not only the actual but, in addition, the potential hazard of contamination of drinking water with bacteria present in superficial soil strata is indicated.

Bacteriological Techniques↗
PubMed1975

Comparative study of four microporous filters for concentrating viruses from drinking water.

Four microporous virus-absorbent filter media for recovering low levels of virus from 380 liters of drinking water were compared. In addition two of the filter media were compared with 1,900 liters of drinking water. The filter media evaluated were MF nitrocellulose membranes (293 mm), AA Cox M-780 epoxy-fiberglass-asbestos disks (267 mm), K-27 yarn-wound fiberglass cartridges + AA Cox M-780 disks (127 mm), and Balston epoxy-fiberglass tubes (24.5 by 63.5 mm). The filters were used to concentrate seeded poliovirus from 380 liters of finished drinking water. Sodium thiosulfate was added to the drinking water to neutralize chlorine, and hydrochloric acid was added to adjust the pH to 3.5. Virus was eluted from the filters with glycine-NaOH buffer at pH 11.5. In terms of virus recovery efficiency, the filter media ranked Balston greater than Cox 267-mm greater than MF 293-mm congruent to K-27 + Cox 127-mm, but differences were slight. The Balston filters and holders were also superior to the other systems in terms of size, weight, cost, and handling factors. Experiments with 2- and 8-mum porosity Balston filters showed no statistically significant difference in virus recovery. Virus was readily detected by the Balston and the MF 293-mm systems at input levels of 12 to 22 PFU/1,900 liters. Preliminary experiments indicated that an elution pH lower than 11.5 may be satisfactory.

Asbestos↗
PubMed1979

Viruses in drinking-water. Reconsideration of evidence for postulated health hazard and proposals for virological standards of purity.

Stringent virological standards for drinking-water have been proposed by the World Health Organisation and by others, but there is no evidence of the spread of virus infection by drinking-water that has been adequately treated to conventional bacteriological standards. There is evidence for waterborne transmission of hepatitis and viral gastroenteritis but the case for the introduction of virological standards is critically examined. It is concluded that there is no evidence that drinking-water in the U.K. contributes to the spread of virus infection, and that the introduction of virological standards for drinking-water could not at present be justified. Moreover, in the absence of any information relating the degree of viral contamination to disease, there is no logical basis on which to set the level of a practical virological standard.

Disease Outbreaks↗
PubMed1979

Kinetics of Cl02 and effects of Cl02, Cl02-, and Cl03- in drinking water on blood glutathione and hemolysis in rat and chicken.

Since chlorination of drinking water produces organochlorinated substances (some possibly carcinogenic), the use of chlorine dioxide disinfectant would avoid halogenation. There is scarcely any data published on the effects of ClO2 in drinking water on human or animal health. The kinetics of 36ClO2 was studied in rats. Radioactivity was rapidly absorbed from the gastrointestinal tract following the administration of (0.07 microCi) 36ClO2 orally. 36Cl in plasma reached at peak at 1 hr. The half life for the elimination of 36Cl from the rat was 44 hr, corresponding to a rate constant of 0.016 hr-1. After 72 hr radioactivity was highest in plasma, followed by kidney, lung, stomach, duodenum, ileum, liver, spleen, thymus, and bone marrow. 36Cl excretion was greatest at 24 and 48 hrs after the administration of 36 ClO2. Forty-three percent of the total initial dose was excreted at 72 hr in the urine and feces. No 36 Cl was detected in expired air throughout the 72 hr studied. ClO2, ClO2-, and ClO3- (1, 10, 100, 1000 ppm) given daily in drinking water decreased blood glutathione, decreased osmotic fragility, and changed the morphology of erythrocytes in both chicken and rat after two months. Methemoglobin was not detected throughout these studies.

Animals↗
PubMed1979

Blood levels of sulfamethazine achieved in beef calves on medicated drinking water.

Studies on the use of sodium sulfamethazine in drinking water at three levels (572, 1028 and 1848 mg/L) were conducted in healthy weaned beef calves under similar dietary and environmental conditions. Blood sulfonamide levels greater than 5 mg/dl were attained with each treatment level but at different time intervals. The maximum levels in blood were achieved with the highest concentration in the water. However, a reduction in water intake caused a lower than anticipated dose of sulfamethazine. Under the conditions of the experiment the administration of sulfonamide in drinking water may be an effective means of mass medication of cattle.

Animals↗
PubMed1979

[Rate of dental caries in youths from communities of both naturally high and low, resp., fluoride content in drinking water (author's transl)].

The incidence of caries in terms of the so-called DFS (= Decayed filled surfaces) index was ascertained for test persons aged from 6 to 15 years, in a community with a drinking water supply having a naturally increased fluoride content (Falkenberg/Oberpfalz, 1.8 ppm F') in comparison with test persons from a neighbouring community with a drinking water supply having a low-fluoride content (Fuchsmühl/Oberpfalz, 0.05 ppm F'). In 103 persons tested (corresponding to 7,577 dental surfaces surveyed) from Falkenberg, the DES index was 5.3, in 123 test persons (corresponding to 10,473 dental surfaces surveyed) from Fuchsmühl the DFS index was 12.4, which means that the naturally increased fluoride content of the drinking water caused caries to drop by 58 per cent viv-à-vis the reference group. No appreciable differences were found to exist in the eruption times of the permanent teeth in both groups of test persons, i. e. fluoride in drinking water does not appear to delay the eruption of teeth. The incidence of fluoride-induced enamel hypoplasia as determined by Kunz on the same test persons, resulted in a distinct increase of 74 per cent for the "fluoride group" vis-à-vis the reference group with a 33 per cent increase only.

Adolescent↗