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1.
In the present study assessment of physicochemical and bacteriological parameters of Lake Fateh Sagar of Udaipur (Rajasthan), India was done. Water samples were collected during different seasons for analysis of physicochemical parameters such as pH, temperature, total alkalinity, total hardness, dissolved oxygen, biological oxygen demand and chemical oxygen demand. In addition, the bacteriological analysis like total bacterial and coliform count was detected. Incidences of Escherichia coli and their antibiotic resistance pattern were analyzed, which is the major microbiological indicator of faecal contamination. The values of some physicochemical and many of the bacteriological parameters were found above the permissible limits for drinking water recommended by World Health Organization. E. coli isolates were identified by morphological, biochemical and molecular characteristics using E. coli specific 16S rRNA gene based primers namely 16E1, 16E2 and 16E3 and universal primers namely 27F and 1492R by PCR. It was found that most of E. coli strains were strongly resistant to kanamycin, ampicillin, cefixime, polymyxin B, penicillin, vancomycin, rifampicin and streptomycin. The study of water quality is of significant value because the drinking water supply of the city is dependent on this lake and present study indicated that the lake water is polluted with reference to these analyzed parameters. 相似文献
2.
The objective of this research was to evaluate the groundwater chemical and bacteriological quality in the Barranquita-Knutzen basin (Córdoba, Argentina). The main purpose was to trace contamination through the examination of bacteriological parameters and antibiotic resistance of Escherichia coli, relating them to surface water, hydrogeological features and land use. Thus, 40 water samples were collected. The major chemical components and bacterial indicators were determined and antibiotic resistance was analysed using standard methods. Multivariate factorial analysis showed that the first principal component (PC) reveals the process of water mineralization, while the second and the third PCs explain a low percentage of variance, but collect chemical constituents and total and faecal coliform bacteria, respectively, revealing specific contamination situations. The observed antibiotic resistance profiles of E. coli and their relation with the land uses revealed that the source of faecal contamination in water is mainly from animal residues. 相似文献
3.
S. Kumar 《洁净——土壤、空气、水》1990,18(6):683-690
In three drinking water sources i. e. river, well and filter water, there were detected 50 taxa of animals: 10 amoebae and 2 ciliates (protozoa), 24 rotifera, 5 cladocerans, and 9 copepods. Chief components of the rotifers population were Brachionus and Keratella, although K. cochlearis is the most common form at all the sites. The presence of Entamoeba histolytica in well water was indicative of faecal contamination which may become a causative agent of amoebiasis in human beings. 相似文献
4.
W. Stelzer 《洁净——土壤、空气、水》1985,13(2):207-215
From river water there were isolated 21 species (mainly coliform bacteria) in 914 strains. Of the pure cultures of coliform bacteria (E. coli, Enterobacter, Klebsiella, Citrobacter) 74.1 % of E. coli and 23.2 % of the Klebsiella strains showed lactose decomposition with gas formation at 44 °C. More than 90 % of the isolated Klebsiella did not form indole. Therefore, the temperature test and the indole formation (at 44 °C) (TI-test) made a very specific detection of E. coli in water possible. 94.7 % of the cultures grown initially on endoagar after a positive TI-test proved to be E. coli. The detection of E. coli showed a very good agreement with the standard method and the TI-test, the detection with the standard method being considerably dependent on the number of checked coliform colonies. 相似文献
5.
A two-part study conducted in Elimbah Creek, a shallow estuarine waterway in south-east Queensland, Australia, examined the variations in physico-chemical parameters of water quality, chlorophyll a, and faecal indicator bacteria abundances of total coliform, Escherichia coli and enterococci, spatially at high and low tide and also over a 12h tidal cycle. Gradients of increasing faecal indicator bacteria from the mouth to the upper, tidal freshwater reaches were observed, despite isolated peaks during either tidal phase. Phytoplankton biomass (measured as chlorophyll a) did not noticeably increase during the study. Variations in the abundances of all three faecal indicator bacteria and their correlations with physico-chemical parameters indicated that although the creek was likely subject to some level of faecal contamination, tidal movement serves to limit faecal indicator and phytoplankton levels in the creek through physico-chemical stress and dilution. However, each faecal indicator bacteria investigated provided different estimations of faecal contamination, which challenges the effectiveness of employing a single type of faecal indicator bacteria when investigating the level of faecal contamination in waterways. 相似文献
6.
Investigating evidential reasoning for the interpretation of microbial water quality in a distribution network 总被引：1，自引：1，他引：1
Rehan Sadiq Homayoun Najjaran Yehuda Kleiner 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,21(1):63-73
Total coliforms are used as indicators for evaluating microbial water quality in distribution networks. However, total coliform provides only a weak “evidence” of possible fecal contamination because pathogens are subset of total coliform and therefore their presence in drinking water is not necessarily associated with fecal contamination. Heterotrophic plate counts are also commonly used to evaluate microbial water quality in the distribution networks, but they cover even a wider range of organisms. As a result, both of these indicators can provide incomplete and highly uncertain bodies of evidence when used individually. In this paper, it is shown that combing these two sources of information by an appropriate data fusion technique can provide improved insight into microbial water quality within distribution networks. Approximate reasoning methods like fuzzy logic and probabilistic reasoning are commonly used for data fusion where knowledge is uncertain (i.e., ambiguous, incomplete, and/or vague). Traditional probabilistic frameworks like Bayesian analysis, reasons through conditioning based on prior probabilities (which are hardly ever available). The Dempster–Shafer (DS) theory generalizes the Bayesian analysis without requiring prior probabilities. The DS theory can efficiently deal with the difficulties related to the interpretation of overall water quality where the redundancy of information is routinely observed and the credibility of available data continuously changes. In this paper, the DS rule of combination and its modifications including Yager’s modified rule, Dubois–Prade disjunctive rule and Dezert–Smarandache rule are described using an example of microbial water quality in a distribution network. 相似文献
7.
The use of reclaimed water and its impact on groundwater quality in the middle and southern parts of the Jordan Valley are investigated. The chemical analyses indicate that nitrate and bacteriological pollution is widespread, and thus, seriously affects groundwater use. During the study, 365 water samples were collected from wells and springs to determine the water chemistry and the extent of nitrate pollution. Three hydrochemical facies are identifed, i. e., (Ca–(Mg)–Na–HCO3), (Ca–Na–SO4–Cl) and (Ca–Na–Cl). The change of facies is accompanied by a gradual increase in the groundwater total dissolved solids (TDS), which is mainly controlled by evaporates and carbonates dissolution in the aquifer matrix. Water analyses indicate that the shallow aquifer in the study area is affected by non‐point pollution sources, primarily from natural (manure) and chemical nitrogen (N)‐fertilizers and treated wastewater used for agriculture. The concentration of nitrate in the groundwater ranges from 10 to 355 mg/L. Considerable seasonal fluctuations in groundwater quality are observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the Zarqa River flow. The noticeable levels of total coliform and Escherichia coli in the northern part of the study area may be attributed to contamination from the urban areas, intensive livestock production, and illegal dumping of sewage. Heavy metal concentrations in all samples were found to be significantly lower than the permissible limits for drinking water standards. 相似文献
8.
Groundwater from boreholes and shallow wells is a major source of drinking water in most rural areas of Zimbabwe. The quality of groundwater has been taken for granted and the status and the potential threats to groundwater quality have not been investigated on a large scale in Zimbabwe. A borehole and shallow well water quality survey was undertaken between January, 2009 and February, 2010 to determine the chemical and microbial aspects of drinking water in three catchment areas. Groundwater quality physico-chemical indicators used in this study were nitrates, chloride, water hardness, conductivity, alkalinity, total dissolved solids, iron, magnesium, manganese, potassium, calcium, fluoride, sulphates, sodium and pH. The microbiological indicators were total coliforms, faecal coliforms and heterotrophs. Principal component analysis (PCA) showed that most of the variation in ground water quality in all catchment areas is accounted for by Total Dissolved Solids (TDS), electrical conductivity (EC), sodium, bicarbonate and magnesium. The principal dissolved constituents in ground water are in the form of electrically charged ions. Nitrate is a significant problem as the World Health Organization recommended levels were exceeded in 36%, 37% and 22% of the boreholes in the Manyame, Mazowe and Gwayi catchment areas respectively. The nitrate levels were particularly high in commercial farming areas. Iron and manganese also exceeded the recommended levels. The probable source of high iron levels is the underlying geology of the area which is dominated by dolerites. Dolerites weather to give soils rich in iron and other mafic minerals. The high level of manganese is probably due to the lithology of the rock as well as mining activity in some areas. Water hardness is a problem in all catchment areas, particularly in the Gwayi catchment area where a value of 2550 mg/l was recorded in one borehole. The problems with hard water use are discussed. Chloride levels exceeded the recommended levels in a few areas under irrigation. Most of the chloride is probably from agricultural activity particularly the application of potassium chloride. Fluoride levels were particularly elevated in the Gwayi catchment area and this is because of the geology of the area. There was no evidence of microbial contamination in all the boreholes sampled as the total coliform, faecal coliforms, heterotrophs count was nil. However, severe microbial contamination was found in the wells especially those in clay areas. 相似文献
9.
The distribution of faecal coliform densities found in New York Bight sediments indicated that sewage sludge material has contaminated areas extending 11 km north and 37 km south from the disposal site. A high degree of confidence for enumerating faecal coliforms in marine sediments was demonstrated by standard water methodology since 82.3% of the faecal coliform group isolated were Escherichia coli. This study also indicated that marine sediments could be stored 4 days at 4°C without appreciable changes in the faecal coliform count, and that, in situ, faecal coliforms would persist longer when sediment temperatures were low. 相似文献
10.
将府河从都江堰宝瓶口段至望江公园段分设9个监测点,在秋冬、春夏两季分别取水,首次建立由细菌总数、总大肠菌群数及粪大肠菌群数三个微生物学指标组成的体系,对府河两季水质进行对比监测分析,以综合评价水质、分析季节影响因素并反映出污染物来源.以都江堰宝瓶口大肠杆菌耐药率作为背景值,对整个河段的9个采样点分离纯化鉴定得到102株大肠杆菌,用K-B法进行对比药敏试验.结果表明,府河从都江堰段起,穿过成都市区后,至望江公园段细菌总数、大肠菌群数及粪大肠菌群数虽有波动,但细菌总数总体呈增加趋势,春夏季府河营养富集,水质有所降低.府河中大肠杆菌耐药性较小,β-内酰胺类耐药率在0.96％～33.33％之间,氨基糖苷类1.39％～7.84％,氟喹诺酮类11.43％～11.76％,磺胺类复方新诺明为52.78％,其中β-内酰胺类耐药性、氟喹诺酮类耐药性与源头水质有关,其余与医疗机构排放的废水及生活污水有关,此研究为控制成都府河水体中的污染防控提供了理论依据. 相似文献
11.
ABSTRACTThe scientific literature has focused on uncertainty as randomness, while limited credit has been given to what we call here the “seventh facet of uncertainty”, i.e. lack of knowledge. This paper identifies three types of lack of understanding: (i) known unknowns, which are things we know we don’t know; (ii) unknown unknowns, which are things we don’t know we don’t know; and (iii) wrong assumptions, things we think we know, but we actually don’t know. Here we discuss each of these with reference to the study of the dynamics of human–water systems, which is one of the main topics of Panta Rhei, the current scientific decade of the International Association of Hydrological Sciences (IAHS), focusing on changes in hydrology and society. In the paper, we argue that interdisciplinary studies of socio-hydrological dynamics leading to a better understanding of human–water interactions can help in coping with wrong assumptions and known unknowns. Also, being aware of the existence of unknown unknowns, and their potential capability to generate surprises or black swans, suggests the need to complement top-down approaches, based on quantitative predictions of water-related hazards, with bottom-up approaches, based on societal vulnerabilities and possibilities of failure.
Editor D. Koutsoyiannis; Associate editor S. Weijs 相似文献
12.
ABSTRACTThe scientific literature has focused on uncertainty as randomness, while limited credit has been given to what we call here the “seventh facet of uncertainty”, i.e. lack of knowledge. This paper identifies three types of lack of understanding: (i) known unknowns, which are things we know we don’t know; (ii) unknown unknowns, which are things we don’t know we don’t know; and (iii) wrong assumptions, things we think we know, but we actually don’t know. Here we discuss each of these with reference to the study of the dynamics of human–water systems, which is one of the main topics of Panta Rhei, the current scientific decade of the International Association of Hydrological Sciences (IAHS), focusing on changes in hydrology and society. In the paper, we argue that interdisciplinary studies of socio-hydrological dynamics leading to a better understanding of human–water interactions can help in coping with wrong assumptions and known unknowns. Also, being aware of the existence of unknown unknowns, and their potential capability to generate surprises or black swans, suggests the need to complement top-down approaches, based on quantitative predictions of water-related hazards, with bottom-up approaches, based on societal vulnerabilities and possibilities of failure.
Editor D. Koutsoyiannis; Associate editor S. Weijs 相似文献
13.
Guam has one of the finest limestone aquifers in the world. Located in the northern half of the island, this vital underground resource supplies the local community with about 80% of its drinking water needs. The majority of the island’s approximately 180,000 inhabitants live in the northern half of the island where significant economic growth and urban development have occurred over the last 30 years. The U.S. military has also occupied large tracts of land in this region for the past 60 years. The risks of groundwater contamination are, therefore, very real considering the population density in northern Guam and the rapid recharge rates to the underlying aquifer. Since April 1996, Guam Waterworks Authority (GWA) has regularly monitored the island’s drinking water resources for chemical and biological contaminants in accordance with the U.S. Safe Drinking Water Act requirements. This report summarizes and compares the groundwater data sets for two discrete time intervals: 1996 through 2001 and 2002 through 2007 for chemicals, and 1997(8) through 2002 and 2003 through 2007 for bacteria. Adaptive management strategies that evolved to deal with contaminant violations over this time frame are critically discussed. Overall, 95% of all GWA’s drinking water production wells were considered to be in relatively good shape from a chemical standpoint. Identified chemicals of concern were chlordane, ethylene dibromide, perchloroethylene, trichloroethylene, and nitrate. The microbiological integrity of Guam’s groundwater was, by comparison, less impressive prior to 2003 because of numerous wastewater spills, leaks, and overflows. Improved management practices introduced shortly afterward have significantly reduced the incidence of Escherichia coli contamination in recent years. 相似文献
14.
U. Schlosser 《洁净——土壤、空气、水》1991,19(3):319-326
Today, bank filtration and artificial recharge of groundwater are two important process steps of the obtaining of drinking water, in view of the fact that the pollution of surface waters has considerably increased. If surface waters are highly polluted, in many cases a preliminary treatment is necessary. To provide protection from heavy bacterial contamination, it is recommended to orientate towards a bottom passage of the infiltrating surface water of at least 100 days. Under favourable conditions, the periods of survival are 100 days for E. coli, 100 days for Salmonella typhii, up to 200 days for Yersinia, and up to 250 days for polioviruses. A high quality of the drinking water obtained from bank-filtrated and infiltrated water is secured by protection of waters from pollutions in their catchment areas and by a drinking water treatment meeting all hygienic demands. 相似文献
15.
Storm events are major transporters of faecal microbial contaminants, but few studies have reported storm loads or concentration dynamics in relation to discharge or other pollutants, notably fine sediment. Episodically, high loads of faecal contamination during storm flows impact downstream uses of water bodies, particularly contact recreation and shellfish harvesting. We examined the storm dynamics of Escherichia coli, turbidity and discharge in the mixed land use Motueka catchment (2047 km2; 60% forest and 19% pasture) to gain insights into E. coli sources and transport. We also explored different approaches for calculating E. coli loads. Discharge and field turbidity were recorded continuously, and E. coli concentrations were sampled during events, over a 13‐month period near the mouth of the Motueka River. E. coli loads were estimated by interpolation, averaging estimators and by using linear regression with smearing correction of the log‐transformed variables: discharge, turbidity, and both turbidity and discharge. The annual E. coli load was dominated (～98%) by export during events. Comparison of monthly monitoring with the intensive storm monitoring campaign suggests that simple stratification of the sampling into storm and baseflow would greatly improve export estimates. E. coli peak concentrations always preceded discharge and turbidity peaks (which had similar timing). Turbidity can be a useful surrogate for faecal microbes in smaller catchments, but in the Motueka turbidity was no better for predicting E. coli concentration than discharge. Runoff from grazed pasture and direct deposition from livestock are probably the ultimate E. coli sources in the Motueka catchment. However, in‐channel stores seem to dominate E. coli dynamics during events and account for the typical feature of bacterial concentrations peaking ahead of discharge and turbidity. This study demonstrates the importance of storm events to faecal microbial loads and shows that E. coli concentration dynamics may contrast with those of turbidity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
16.
Edwin E. Geldreich 《水文研究》1996,10(2):315-333
Numerous pathogenic agents have been found in freshwaters used as sources for water supplies, recreational bathing and irrigation. These agents include bacterial pathogens, enteric viruses, several protozoans and parasitic worms more common to tropical waters. Although infected humans are a major source of pathogens, farm animals (cattle, sheep, pigs), animal pets (dogs, cats) and wildlife serve as significant reservoirs and should not be ignored. The range of infected individuals within a given warm-blooded animal group (humans included) may range from 1 to 25%. Survival times for pathogens in the water environment may range from a few days to as much as a year (Ascaris, Taenia eggs), with infective dose levels varying from one viable cell for several primary pathogenic agents to many thousands of cells for a given opportunistic pathogen. As pathogen detection in water is complex and not readily incorporated into routine monitoring, a surrogate is necessary. In general, indicators of faecal contamination provide a positive correlation with intestinal pathogen occurrences only when appropriate sample volumes are examined by sensitive methodology. Pathways by which pathogens reach susceptible water users include ingestion of contaminated water, body contact with polluted recreational waters and consumption of salad crops irrigated by polluted freshwaters. Major contributors to the spread of various water-borne pathogens are sewage, polluted surface waters and stormwater runoff. All of these contributions are intensified during periods of major floods. Several water-borne case histories are cited as examples of breakdowns in public health protection related to water supply, recreational waters and the consumption of contaminated salad crops. In the long term, water resource management must focus on pollution prevention from point sources of waste discharges and the spread of pathogens in watershed stormwater runoff. 相似文献
17.
The physico‐chemical characteristics and microbial composition of the final effluents of two municipal wastewater treatment plants in South Africa were assessed between July and September 2009. The impact of the treated final effluents on the receiving water bodies was also evaluated. The temperature across all sampling points ranged between 14 and 22°C, while pH varied from 6.9 to 7.6. High levels of turbidity, chemical oxygen demand (COD), ammonia, nitrate, nitrite and orthophosphate (PO4) were observed in many cases. Turbidity of the samples was in the range of 2.2–288.6 NTU. The concentrations (mg/L) of other physico‐chemical parameters are as follows: COD (9.33–289); ammonia (0.000340–45.4); nitrate (0.062–539); nitrite (0.021–22.6); PO4 (5.3–33.2). The microbial quality of the effluents discharged from the plants did not comply with the limits set by the South African guidelines with respect to pathogens such as Salmonella, Shigella, Escherichia coli, total coliform, faecal coliform, enterococci, faecal streptococci, and viral particles for effluents intended for discharge into receiving watersheds. This study revealed an undesirable impact on the physico‐chemical and microbial qualities of the receiving water bodies as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. This poses a health risk to several rural communities which rely on the receiving water bodies primarily as their sources of domestic water and recreational purposes. There is therefore a need for the intervention of appropriate regulatory agencies in South Africa to ensure compliance of treatment facilities with wastewater effluent quality standards. 相似文献
18.
Touron A Berthe T Gargala G Fournier M Ratajczak M Servais P Petit F 《Marine pollution bulletin》2007,54(9):1441-1450
The Seine estuary, one of the largest estuaries of the European northwest continental shelf, is subjected to numerous anthropogenic influences. Here we present an assessment of the microbial faecal contamination of the estuary water. The most vulnerable areas were defined on the basis of the fluxes of indicator organisms and the occurrence of Salmonella and Cryptosporidium sp. and Giardia sp. (oo)cysts. The microbial quality of the water changes from upstream to downstream: in the upstream area, contamination by faecal-indicator bacteria and Salmonella occurs during periods of high flow; in the urbanized area, mid-way between the uppermost areas of the estuary and its mouth, discharge from a wastewater treatment plant and a tributary degrade water quality; at the estuary mouth, the accumulation of microorganisms attached to particles in the maximum turbidity zone, particularly Clostridium perfringens spores and oocysts of Cryptosporidium, is accompanied by inputs of ThC and Escherichia coli from tributaries. In some areas, significant strong relations are observed between Salmonella, (oo)cysts of protozoan, and levels of faecal indicators. 相似文献
19.
In many smallholder farms in sub-Saharan Africa dambos are used for grazing and crop production especially horticultural crops. Increased use of dambos especially for crop production can result in ground and surface water pollution. Ground and surface water quality along a dambo transect in Chihota, Zimbabwe, was investigated between October 2013 and February 2014. The transect was divided into; upland (control), dambo gardens (mid-slope) and the river (valley bottom). Water samples for quality assessment were collected in October 2013 (peak of dry season) and February 2014 (peak of rainy season). The collected water samples were analysed for pH, faecal coliforms, total nitrogen, electrical conductivity, total dissolved solids (TDS), and some selected nutrients (P, K, Ca, Mg, Na, Zn, and Cu). Water pH was 7.0, 6.4 and 6.1 for river water, garden and upland wells respectively. During the wet season total nitrogen (TN) concentrations were 233 mg/L for uplands, 242 mg/L for gardens and 141 mg/L for the river. During the dry season, TN concentrations were all below 20 mg/L, and were not significantly different among sampling stations along the dambo transect. Dry season faecal coliform units (fcu) were significantly different and were 37.2, 30.0 and 5.0 for upland wells, garden wells and river respectively. Wet season faecal coliforms were also significantly different and were 428.5, 258.0 and 479.4 fcu for upland wells, garden wells and river respectively. The other measured physico-chemical parameters also varied with sampling position along the transect. It was concluded that TN and fcu in sampled water varied with season and that wet season concentrations were significantly higher than dry season concentrations. High concentrations of faecal coliforms and total N during the wet season was attributed to increased water movement. Water from upland wells, garden wells and river was not suitable for human consumption according to WHO standards during both the dry and wet seasons. 相似文献
20.
Erika K. Wallender Elizabeth C. Ailes Jonathan S. Yoder Virginia A. Roberts Joan M. Brunkard 《Ground water》2014,52(6):886-897
Disease outbreaks associated with drinking water drawn from untreated groundwater sources represent a substantial proportion (30.3%) of the 818 drinking water outbreaks reported to CDC's Waterborne Disease and Outbreak Surveillance System (WBDOSS) during 1971 to 2008. The objectives of this study were to identify underlying contributing factors, suggest improvements for data collection during outbreaks, and inform outbreak prevention efforts. Two researchers independently reviewed all qualifying outbreak reports (1971 to 2008), assigned contributing factors and abstracted additional information (e.g., cases, etiology, and water system attributes). The 248 outbreaks resulted in at least 23,478 cases of illness, 390 hospitalizations, and 13 deaths. The majority of outbreaks had an unidentified etiology (n = 135, 54.4%). When identified, the primary etiologies were hepatitis A virus (n = 21, 8.5%), Shigella spp. (n = 20, 8.1%), and Giardia intestinalis (n = 14, 5.7%). Among the 172 (69.4%) outbreaks with contributing factor data available, the leading contamination sources included human sewage (n = 57, 33.1%), animal contamination (n = 16, 9.3%), and contamination entering via the distribution system (n = 12, 7.0%). Groundwater contamination was most often facilitated by improper design, maintenance or location of the water source or nearby waste water disposal system (i.e., septic tank; n = 116, 67.4%). Other contributing factors included rapid pathogen transport through hydrogeologic formations (e.g., karst limestone; n = 45, 26.2%) and preceding heavy rainfall or flooding (n = 36, 20.9%). This analysis underscores the importance of identifying untreated groundwater system vulnerabilities through frequent inspection and routine maintenance, as recommended by protective regulations such as Environmental Protection Agency's (EPA's) Groundwater Rule, and the need for special consideration of the local hydrogeology. 相似文献