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At least 865 records · Page 48Linked to original sources
PubMedDate not supplied

[Importance of the results of a virological examination of sewage. A comparison of the series of enteroviruses isolated from sewage and from the feces of virus excreters].

Simultaneous examinations for the presence of enteroviruses were carried out on sewage of the central aeration station, periferal collectors of the most populous institutions, preschool children's institutions as well as feces of children attending these institutions in a community of urban type. A high degree of coincidence of spectra of enteroviruses isolated from sewage of the central station, periferal collectors, sewage of children's institutions, and from the feces of most virus excretors was demonstrated. No enteroviruses found in occasional virus excretors were detected in sewage. Enteroviruses were regularly found in sewage of periferal collectors if approximately 10% of children excreted a certain virus type simultaneously.

Carrier State↗
PubMedDate not supplied

[Importance of the results of a virological examination of sewage. A quantitative evaluation of the finding of enteroviruses in sewage].

In order to evaluate quantitatively the effectiveness of virological examinations of sewage, a labeled virus in a dose of 7.5X10(9) PFU was introduced into the canalization system of a community. Such an amount of virus could be found in the canalization system if 5--10% of the residents would excrete it simultaneously. The labeled virus was selectively detected in the community sewage. This procedure has demonstrated that the routine methods for sewage collection, specimen treatment, and virus isolation permit virus detection when 5--10% of this virus excretors are available. The labeled virus entered the canalization system most actively within the first 2 hours after administration, then its amount declined, and within 24 hours ceased. The labeled virus was found on all swabs which were in the sewage flow since the time of administration to the 7th day. The maximum amount of virus was found on the swab which was in the sewage flow for the first 2 hours after virus administration. By 7 days the amount of labeled virus on swabs decreased 10-fold. Under experimental conditions, in sewage kept at 25 degrees C enteroviruses of the group of poliomyelitis, ECHO, and Coxsackie had approximately similar inactivation rate (0.16--0.22 Ig TCD50 per day) and the half-life period (1.3 days), that is, in 7 days the virus titer on a swab should decline by 1.0--1.5 Ig TCD50.

Enterovirus↗
PubMed1990

[An experimental study of the toxicological characteristics of ships' wastes for the hygienic validation of technological layouts of new water-protection equipment].

The effect of waste waters, as well as of waste waters, that had undergone physicochemical treatment and disinfection, on the organism of experimental animals was investigated. The influence of purified and nonpurified sewage on the morphological structure of organs (liver, brain, kidney, myocardium), on the biochemical processes in experimental animals' tissues, on the immune reactivity of experimental animals was determined. The improvement of the morphological structures of the organs under study, of certain biochemical indices and bioimmunological reactivity of animals under peroral and dermal exposure to the purified waste waters gives the grounds for the conclusion on the biological safety and effective detoxication of waste waters which have undergone purification with the use of aluminum-containing coagulant of the aluminum oxichloride type, and which have been disinfected by ultraviolet irradiation.

Animals↗
PubMed1990

[The hygienic assessment of the ozonizer units for the housekeeping water supply of ships].

According to the results of the studies the reason of the worsening of water quality in the ozonizer [correction of ozonating] installations of household water supply of ships is the presence of negative biological processes in the system of household and drinking water in combination with the peculiarities of its operation and reliability of functioning of the ship ozonizer [correction of ozonating] station. New technological designs and automated control methods, maintaining the residual ozone doses in the ship network, are needed to keep the drinking quality of water in the system.

Evaluation Studies as Topic↗
PubMed1990

[The hygienic assessment of D-51A rubber and the conditions for its practical use in household drinking water supply].

Rubber D-51A under examination, treated by thiuram, following long-time contact with drinking water (static conditions of the experiment) discharges thiuram into it, which significantly worsens the water quality. Drinking of this water by animals leads to functional disturbances in their organisms. Short-time contact of rubber D-51A with drinking water does not cause deterioration of its quality. Therefore rubber D-51A can be recommended to be used as pump gaskets.

Animals↗
PubMed1990

[The scientific bases of the document "Health Standards and Regulations for the Design and Operation of Centralized Hot Water Supply Systems"].

Scientific substantiation of the choice of a heat supply system, of temperature regimen for the hot water, of the scale of laboratory-production control over the hot water quality, conditions for the hydrochemical washing out of the tubes depending on the heat supply system is given in the article. Requirements to accumulating tanks which, in case of disturbances in the operational regimen, may produce unfavourable effects on the hot water quality.

Heating↗
PubMed1990

Removal of lead from aqueous solution by Acinetobacter calcoaceticus.

A bacterial strain tolerant to the presence of 400 ppm lead was isolated from digested sewage sludge. The organism was identified as Acinetobacter calcoaceticus var: anitraus (98% confidence). Both viable and formalin-inactivated bacterial cells could remove Pb from an aqueous solution. The Pb-binding ability of inactivated cells was compared with that of a commercial ion-exchange resin. Amberlite IR-120. The metal-binding ability of A. calcoaceticus followed the sequence Pb greater than or equal to Cu greater than or equal to Cr greater than or equal to (Cd, Ni, and Zn) greater than or equal to Co. The ability of the inactivated cells to remove Pb was pH sensitive, and the adsorption process was slightly affected at high temperature (70 degrees C). The adsorption and desorption process worked equally well with A. calcoaceticus embedded in a polyacrylamide gel matrix.

Acinetobacter↗
PubMed1990

[Effects of soil and ground water pollution with perchloroethylene from the public health service viewpoint].

A routine analysis of drinking water conducted in September 1987 in a Rhenish water works revealed a perchloroethylene (PER) content of 3 micrograms/l. Within less than 3 months the concentration in the two northern wells of the entire battery consisting of 4 wells rose to 20 micrograms/l, and hence the complete battery had to be shut off from the water supply network. The pumped-up water was diverted to a draining plant via the precipitation tank of the water works. During the two subsequent months the PER concentration continued to rise, especially in well No. 1, to more than 120 micrograms/l. The present report deals with the measures undertaken to assess the extent of the damage and the effects of the incident on drinking water supply, on the storage of foods in a warehouse, on a planned sewer construction and on the systems installed by various parties for their own water supply, and on wells in private gardens and in a gardening nursery.

Food Analysis↗
PubMedDate not supplied

[Status of water supply treatment techniques].

The paper portrays the difficulties with which the water works presently have to contend in the preparation of drinking water from polluted sources. Particular emphasis is on describing the present state of water treatment methods and what they are capable of achieving. After an overview of the substances found in ground and surface water that impair the preparation of drinking water, the methods available today for water treatment are described. Finally, practical examples showing the most effective combination of these methods in modern water treatment plants are presented.

Disinfection↗
PubMedDate not supplied

[Current status of bath water treatment techniques].

The Federal German DIN standard No. 19644 that has been enforced in West Germany since 1989 had to be revised in view of the fact that German legislation is expected to issue an ordinance on swimming pool and public bath water within the framework of the Federal Communicable Diseases Act; furthermore, the need for revision also arose from the solution of the hygienic problems of treatment and disinfection of warm whirlpool water, and from the necessity of modifying several now outdated regulations. It is the aim of public health legislation to prevent health risks of bathers and of attendant staff by Legionella pneumophila in all types of basins with additional water cycles and intake of air (aerosol formation); likewise, adverse health effects of side reaction products of the disinfectant chlorine (i. e. chloroamines and halogenated organic compounds, especially the trihalomethanes) must be avoided. Recent research has shown that these aims can be achieved by altering the mode of running and backwashing filters of all process combinations including those using ozone and introducing an additional absorption on powdered activated carbon, and the process combination of flocculation-filtration-chlorination. Improved treatment would be without effect if turnover rates could not be assessed reliably for basins of irregular geometry--as they are preferably used today--operated with additional water cycles involving intake of air. Lack of costly investigations prompts users to estimate turnover rates on the basis of experience collected with basins of square or rectangular dimensions.

Baths↗
PubMed1990

[An evaluation in the Ames test of the mutagenicity of the sewage and industrial effluents from the Baikal Paper and Pulp Combine].

The use of the Ames test for the analysis of industrial effluents from cellulose production and sewage waters varying in the degree of purification with the aid of a metabolic activation system from rat and fish liver with Salmonella strains TA 98 and TA 100 revealed a strong direct mutagenic effect of strain TA 100 in samples after cellulose chlorination. The multistage procedure of sewage water purification allows to remove practically completely the mutagenic substances. A simultaneous study of cytotoxic effects of industrial effluents on mammalian cells shows that the mutagenic activity is exhibited in not toxic concentrations. The urgency of a regular biological control over the genotoxicity of industrial effluents from the sulfate production of cellulose is under discussion.

Animals↗
PubMed1990

Evaluation of traditional filters for water purification in Burkina Faso.

Most tropical water springs are polluted with microbial agents such as faecal coliforms and streptococci, so for the present and the forseeable future, boreholes are considered to be the most appropriate system for reducing the bacterial contamination of water. However, from source to consumer, safe drinking water usually becomes polluted with faecal bacteria. This observation which calls into question the success of the International Drinking Water Supply and Sanitation Decade should stimulate efforts to provide a reliable means of water purification. The use of traditional filters prepared with sand, gravel and charcoal has been proposed but our results reveal that they give no guarantee for the purification of bacteria-polluted water.

Burkina Faso↗
PubMedDate not supplied

[Water quality and microbiological status of the distribution system: traditional parameters and emerging parameters].

Most pollution of drinking water is caused by inadequacy of the uptake and distribution systems, by insufficient upkeep of the sewage system and by defects or breaks in the disinfection processes. This may be the cause of waterborne epidemic outbreaks and therefore it is necessary carry out routine controls by simple and rapid tests for the detection of intestinal organisms. In the light of minor hepatitis A epidemics occurred in the town of Messina, we have carried out a study to determine the drinking water quality. To this end, in addition to the traditional tests recommended by CEE and required by the 8/2/1985 DPCM (37 degrees C and 20 degrees C viable count, total and faecal coliforms and faecal streptococci), we have carried out P. aeruginosa, coliphages and gram-negative endotoxins tests, in 74 water samples drawn on way in and way out of the tanks and along the piping system. Only 12.5% of the sixteen water samples drawn on way in (before disinfection system) was in compliance with the law. 75% of these samples showed positivity for faecal streptococci. The water quality was lower in the fourteen water samples drawn on way out of the tanks (7.1% was in compliance with the law). The percent of positivity along the piping system for total and faecal coliforms and for faecal streptococci was 34.1, 15.9 and 59.1 respectively. Coliphages were always absent. P. aeruginosa was almost always present in way in water (93.7%). Moreover this microorganism was recovered in 85.7% of the samples drawn on the way out and in 77.3% along the piping system. In the same drawing places endotoxins were present at high percentage (100%, 85.7% and 90.9%). These values come from high test sensitivity and poor water quality. Finally we have pointed out the importance of all the parameters examined. The significance of coliform bacteria is known, but we consider very important, as organisms indicative of pollution, the enterococci, since they P. aeruginosa may survive long time in fresh water though it is not autoctone, but, in general, of faecal origin. Several soluble antigens of this microorganism as well as enterococci show positive LAL tests (1-5-6). The endotoxin content in fresh water reflects the degree of bacterial contamination. We believe, therefore, it is needed to fix an upper limit to endotoxins in drinking water. Coliphages concentrations could be correlated with enteric virus concentrations but the ratio of coliforms to coliphages is about 100:1. Therefore this indicator of viral pollution is helpful only for highly polluted surface waters.

Bacteria↗