摘要:

AbstractInterrelationships between the morphological and physiological properties of selected cyanobacterial species distinguished in the laboratory are used to simulate their population dynamics against realistic scales of environmental variability. Differences in performances are shown to correlate well with the ambient conditions found in the various types of lakes in which cyanobacteria are typically distributed.

ISSN:0884-8181    

DOI:10.1002/tox.2540040302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractResponsibility for drinking water quality in Canada is primarily a provincial obligation, but the Department of National Health and Welfare (NHW) plays an important role in the establishment of national guidelines, conducting research on problems of national concern, and providing advice on point‐of‐use devices. The microbiological quality of drinking water is regarded as one of the most important parameters in view of the low but continuing reports of waterborne disease. During the period from 1974 to 1982, there were 42 reported outbreaks involving 1789 persons. The known causative agents were bacteria,Giardia, and viruses.The microbiology program of NHW includes development of the microbiological parameters in theGuidelines for Canadian Drinking Water Quality, collecting and disseminating the data on waterborne disease in Canada, sponsoring and collaborating in research studies on the microbiological hazards in drinking water, participating in the investigation of local and regional water problems, testing and evaluation of point‐of‐use water treatment devices, and providing educational material for the public and the media. Each of these aspects is described in this paper. Particular emphasis is placed on the waterborne illness in the last decade and some of the results of the studies onGiardiaremoval or inactivation in potabl

ISSN:0884-8181    

DOI:10.1002/tox.2540040303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractFifty‐seven water samples in all were collected in a northern (latitude 69° N) and in a southern (latitude 61° N) region from waters in the “natural state.” Coliform populations were studied by collecting random isolates of typical sheen colonies from Endo LES 35° C cultivations. The maximum growth temperatures of 607 strains were measured. Identification of 372 isolates was attempted by using the API 20EC and 20E systems. Eleven species were found—seven of them common to both regions. Twenty‐nine percent of the strains could not be identified. The most frequent species wasSerratia fonticola(26% of all strains tested), the second wasHafnia alvei(14%), and the thirdEnterobacter cloacae(13%; only encountered in the north). The strains able to grow at or above 44. 5°C were identified asEscherichia coli.In the southern region, environmental coliforms (S. fonticolaandH. alvei) so completely outnumberedE. colithat it was met only once among the 438 total coliform isolates, whereas 23% of the isolates from the northern region wereE. coli.Typical pipeline/biofilm coliform types were not found, with the exception of numerousE. cloacaestrains in the most remote lake samples collected and oneKlebsiella oxytocain a brook. The fecal coliforms (all of themE. coli) were concluded to be of recent animal origin. The standard fecal coliform analysis was estimated to function extremely well in the pristine waters of our subarctic climate. The total coliform analysis has no indicator value under these

ISSN:0884-8181    

DOI:10.1002/tox.2540040304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractEighty‐seven different mineral waters available for purchase in the Federal Republic of Germany were tested for the presence of heterotrophic bacteria and, specifically, antibiotic‐resistantPseudomonasspecies. Waters lacking carbon dioxide and Heilwasser (waters often prescribed for a variety of ailments) tended to show the highest numbers of bacteria. Eighty‐one isolates ofPseudomonaswere obtained from 39 samples of mineral water. Of the 9 species found,P. cepaciaandP. maltophilia, most commonly associated with nosocomial infections, made up 13. 6% of the isolates. These 2 species also showed the highest resistance to the ten antibiotics used in the study. A comparison of antibiotic resistance patterns between mineral water and clinical isolates from the Medizinische Hochschule, Hannover, shows a higher similarity than that between mineral water and Massachusetts General Hospital (Boston) isolates. With the exception ofP. pseudoalcaligenes, all mineral water isolates showed basically 100% resistance to cefoxitin and were highly resistant to ampicillin. Only 1 of 81 isolates (1. 2%) was resistant to tobramycin, although 2 isolates ofP. cepaciashowed intermediate resistance to this drug. Though noP. aeruginosawere found in any of the samples, the presence of species associated with nosocomial infections and highly resistant to commonly used antibiotics suggests that careful thought be given to the routine ingestion of mineral water by compromised individuals and those with underlying di

ISSN:0884-8181    

DOI:10.1002/tox.2540040305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe objectives of the investigation were to determine specific hydraulic exchange rates that provide water in swim embayments that will meet fecal coliform standards for swimming, and to determine the water quality parameters that reflect rates of exchange of main channel waters with swim embayment waters. Bacteriology, water chemistry and hydraulic exchange rates were determined on three test swim embayments of good, acceptable, or unacceptable water quality. It was concluded that: (1) fecal coliform numbers may increase 50–100% above background even with high hydraulic exchange; (2) 93% of the embayment water must be exchanged every 24 h to meet coliform standards; (3) the ratio of fecal coliforms, turbidity, and temperature in swim waters to those same parameters in exchange waters is the most accurate way of assessing exchange; and (4) sediments act as a repository for enteric bacteri

ISSN:0884-8181    

DOI:10.1002/tox.2540040306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractNumbers of fecal coliforms and fecal streptococci increased during the winter in a stream near a ski area. These numbers returned to background levels within a month after the ski area closed for the year. As the pollution events continued with time, the day of the week on which maximal numbers were obtained changed. Maximum numbers of these bacteria were seen in the afternoons when pollution was occurring. Minimum numbers were found in the morning.Fecal coliforms and fecal streptococci were enumerated in a stream above and below the ski area for three summers. Statistically significant differences in the numbers of these organisms occurred between the months studied, depending upon whether the statistics were run upon numbers per 100 mL or upon numbers passing a point per second.

ISSN:0884-8181    

DOI:10.1002/tox.2540040307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractA total of 200 swimming pools, including one wading pool, were monitored for specific bacteria to select the most appropriate water quality indicators for a proposed prospective epidemiological survey of swimming pools. The organisms included in the study were fecal coliforms, fecal streptococci,Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacterspp., and total plate counts of aerobic heterotrophic bacteria. The results indicated that fecal coliforms, fecal streptococci, andAcinetobacterspp. have limited use as water quality parameters because of their naturally low densities in pools. Total plate counts,P. aeruginosa, andS. aureusappeared to be the indicators of choice because they were either present in large numbers, were opportunistic pathogens, or had a varied susceptibility to chlorine. The study showed thatP. aeruginosahas an added advantage as an indicator because it can be typed using serological and genotyping methods.

ISSN:0884-8181    

DOI:10.1002/tox.2540040308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractMany microbiological tests are currently available for evaluating the suitability of water resources for human use. Cost, speed, simplicity, and the ability of the test to detect microbial contamination are some of the key factors involved in selecting the appropriate test. The performance of the test often depends on the nature of the tested water and hence it is necessary to evaluate the test under local conditions. This paper compares the performance of several microbiological tests on Brazilian waters. These tests include traditional coliform tests, and the presence/absence and coliphage tests.

ISSN:0884-8181    

DOI:10.1002/tox.2540040309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractTwo hundred fifteen cyanobacteria bloom samples collected from different parts of Finland were studied, 35 of which proved to be neurotoxic. Toxicity was determined by mouse bioassay.Anabaenaspecies were present in all neurotoxic samples except one, in whichOscillatoriadominated. The presence of anatoxin‐a in the blooms and in the isolated strains was studied from freeze‐dried materials by gas chromatography/mass spectrometry. The simultaneous occurrence of neurotoxicity and hepatotoxicity in some samples was studied by high performance liquid chromatography and high performance thin layer chromatography. Thirteen out of 30 bloom samples contained anatoxin‐a. In the remaining samples, neurotoxicity was caused by unknown toxin(s). Strains producing anatoxin‐a were isolated from the generaAnabaena, Aphanizomenon, Oscillatoria, and Cylindrospermum.Anatoxin‐a content of the blooms varied from 12 to 4360 μg/g freeze‐dried material. Some strains were able to produce about three times as much anatoxin‐a as was detected in natural blooms. Simultaneous occurrence of neurotoxicity and hepatotoxicity was found in some samples as well as atypical toxic responses in

ISSN:0884-8181    

DOI:10.1002/tox.2540040310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractKinneret, the only natural freshwater lake in Israel, is used as the major source for drinking water and is also utilized for commercial fishing, recreation, and tourism. Recreational pressure was averaged as 190 IKD [Individuals/km (53 km shoreline)/day] during May–September. Total population in the drainage basin (2730 km2) is approximated as 255 × 103. Before 1980, most of the domestic sewage (18000 m3/day) and fish‐pond wastes drained into the lake. The major sources of intestinal and pathogenic bacteria found in lake water were untreated domestic sewage, cows in pasture lands through water runoff, and directly from the recreational population. Partial implementation of a master plan for sewage removal has led to the diversion of about 60% of the sewage into reservoirs constructed in the drainage basin for irrigation reuse. Consequently, the presence of intestinal bacteria in Jordan inlet (the major drainage river) declined. Sewage removal systems were also constructed along all the shoreline. Reduction of intestinal bacteria densities in public beach waters was also recorded. On the other hand, nutrients (mostly P) and phytoplankton (density and composition) in the lake slightly deteriorated water quality. The management design is dependent on water quality standards. In the case of a higher quality standard, lake utilization for drinking requires a thorough treatment and water consumption for irrigation is more effic

ISSN:0884-8181    

DOI:10.1002/tox.2540040311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY