scholarly journals Contamination of groundwater sources in emerging African towns: the case of Babati town, Tanzania

2018 ◽  
Vol 13 (4) ◽  
pp. 980-990 ◽  
Author(s):  
P. A. Pantaleo ◽  
H. C. Komakech ◽  
K. M. Mtei ◽  
K. N. Njau

Abstract Assessment of groundwater contamination potential was carried out in Babati, Manyara, Tanzania. Diazotization, cadmium reduction, ascorbic acid, ion selective electrode and membrane filtration analytical methods were used, respectively, for nitrite, nitrate, phosphate, fluoride and microbial investigations. Fecal coliforms (FC) and high NO3 concentrations were present in wells less than 30 m deep. The maximum FC level was 280 CFU/100 ml, and the nitrate (NO3) ranged from 1.1 to 357.7 mg-NO3/l. In boreholes, nitrate concentrations ranged from 2.3 to 32.6 mg-NO3/l, below both national and WHO standards, and were all free of fecal coliform. Other parameters were all within recommended limits for all wells tested. Evaluation of the potential contamination pathways revealed that the shallow well depths ranged from 1.2 to 26.67 m – median 9 m (N = 366): 70% were unlined and 19% were uncovered. About 74% of the wells were within 30 m of sanitation facilities, of which 60% were traditional pit latrines. The findings revealed that most shallow wells (64%) are polluted and could cause health problems for users. Therefore, it is prudent that the community avoids relying on shallow wells. Boiling of domestic water before use is highly recommended.

1976 ◽  
Vol 22 (12) ◽  
pp. 1774-1776 ◽  
Author(s):  
Susan L. Stramer

Klebsiella pneumoniae is a human and animal pathogen frequently encountered in the environment. The membrane-filtration method utilizing m-FC medium for the detection of fecal coliforms yields a colony type easily distinguishable as K. pneumoniae. These colonies appear as atypical light blue, nucleated, mucoid colonies differing considerably from the typical dark blue fecal coliform colonies.


2018 ◽  
Vol 17 (2) ◽  
pp. 25-31 ◽  
Author(s):  
Bikram Gautam ◽  
Rameshwar Adhikari

Introduction: Membrane filtration (MF) is one of the widely used technique on a routine basis. On the other hand, replica plate (RP) technique can be used to transfer existing bacterial colonies in two plates which even allows pinpointing the original colony. The aim of this study is to comparatively detect the cfu/100 mL of fecal coliform using membrane filtration and replica plate techniques.Methods: In the study, a total of 25 bottled water were selected from the local market in Kathmandu valley. The total coliform count was detected using MF, while fecal coliform was detected using both MF and RP technique.Results: It was found that the average cfu/100 mL for total coliform, fecal coliform (MF) and fecal coliform (RP) were 143.38, 49.82 and 51.00 respectively. Pearson correlation coefficient calculated between total coliform and fecal coliform (MF), total coliform and fecal coliform (RP), fecal coliform (MF) and fecal coliform (RP) were found to be 0.695, 0.733 and 0.990 respectively; implying a positive correlation Conclusions: It has been demonstrated that intrinsic and extrinsic factors influence colony forming units. Furthermore, RP is a more sensitive method for screening fecal coliforms although both MF and RP can be efficiently used.


RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Aluana Ariane Schleder ◽  
◽  
Lucília Maria Parron Vargas ◽  
Fabricio Augusto Hansel ◽  
Sandro Froehner ◽  
...  

ABSTRACT The vulnerability of karst aquifers to contamination by agrochemical compounds was studied. Such contamination occurs due to its geomorphological structure. Despite the fact, aquifers are important to provide potable water, there is a lack of research about karst aquifers in Brazil. The aim of this study was to evaluate the occurrence of nitrates, fecal coliform bacteria and atrazine in shallow and deep wells in the karst aquifer in the State of Paraná, which is affected by agricultural activities. This study was conducted in an intensive agricultural area located inside the basin of the Upper Iguassu/Ribeira in the Municipality of Colombo, Paraná in Brazil. The sampling campaigns were carried out between 2014 and 2015 in fifteen shallow wells and seven deep wells. Nitrates, total and fecal coliforms and atrazine were analyzed. Nitrates were found in higher concentration in all shallow wells, ranging from 0.14 mg L-1 and 40.22 mg L-1. In deep wells, the lower concentrations were between 1.24 mg L-1 e 17.86 mg L-1. The analysis of total and fecal coliforms showed the bias for nitrates. Atrazine was detected in five shallow wells and in four deep wells. Physico-chemical characteristics of atrazine as well as fractures of the karstic aquifer and high hydraulic conductivity can be considered as determining factors in the fate of pesticides.


2002 ◽  
Vol 68 (2) ◽  
pp. 539-544 ◽  
Author(s):  
John M. Pisciotta ◽  
Damon F. Rath ◽  
Paul A. Stanek ◽  
D. Michael Flanery ◽  
Valerie J. Harwood

ABSTRACT The Colilert-18 system for enumeration of total coliforms and Escherichia coli is approved by the U.S. Environmental Protection Agency for use in drinking water analysis and is also used by various agencies and research studies for enumeration of indicator organisms in fresh and saline waters. During monitoring of Pinellas County, Fla., marine waters, estimates of E. coli numbers (by Colilert-18) frequently exceeded fecal coliform counts (by membrane filtration) by 1 to 3 orders of magnitude. Samples from freshwater sites did not display similar discrepancies. Fecal coliforms, including E. coli, could be cultured from 100% of yellow fluorescent wells (denoting E. coli-positive results) inoculated with freshwater samples but could be cultured from only 17.1% of the “positive” wells inoculated with marine samples. Ortho-nitrophenyl-β-d-galactopyranoside (ONPG)-positive or 4-methylumbelliferyl-β-d-glucuronide (MUG)-positive noncoliform bacteria were readily cultured from Colilert-18 test wells inoculated with marine samples. Filtered cell-free seawater did not cause false positives. Coculture preparations of as few as 5 CFU of Vibrio cholerae (ONPG positive) and Providencia sp. (MUG positive) ml−1 inoculated into Colilert-18 caused false-positive E. coli results. Salinity conditions influenced coculture results, as the concentration of coculture inoculum required to cause false positives in most wells increased from about 5 CFU ml−1 in seawater diluted 1:10 with freshwater to ≈5,000 CFU ml−1 in seawater diluted 1:20 with freshwater. Estimated E. coli numbers in various marine water samples processed at the 1:10 dilution ranged from 10 to 7,270 CFU�100 ml−1, while E. coli numbers in the same samples processed at the 1:20 dilution did not exceed 40 CFU�100 ml−1. The lower estimates of E. coli numbers corresponded well with fecal coliform counts by membrane filtration. This study indicates that assessment of E. coli in subtropical marine waters by Colilert-18 is not accurate when the recommended 1:10 sample dilution is used. The results suggest that greater dilution may diminish the false-positive problem, but further study of this possibility is recommended.


2006 ◽  
Vol 1 (4) ◽  
Author(s):  
Huub H.J. Cox ◽  
Steve Fan ◽  
Reza Iranpour

Terminal Island Treatment Plant converted its digesters to thermophilic operation with the objective to comply with the U.S. EPA Part 503 Biosolids Rule requirements for Class A biosolids. The following processes were tested: a) single-stage continuous; b) two-stage continuous; c) single-stage sequencing batch. Salmonella sp. were always non-detect in digester outflows (<3 MPN/4 g dry wt), whereas fecal coliform densities were usually below the Class A limit of 1000 MPN/g dry wt. However, the recurrence of fecal coliforms in post-digestion caused non-compliance with the Class A limit at the truck loading facility as the last point of plant control for compliance. After several design modifications of the post-digestion train, operation of the digesters as sequencing batch digesters according to the time-temperature requirement of Alternative 1 of the Part 503 Biosolids Rule achieved compliance for both Salmonella sp. and fecal coliforms at the last point of plant control (truck loading facility).


1995 ◽  
Vol 31 (12) ◽  
pp. 239-248 ◽  
Author(s):  
Ana Emparanza-Knörr ◽  
Francisco Torrella

The Salmonella presence and the microbiological quality indicators, total and fecal coliforms and coliphages of E. coli C, have been studied in a overloaded wastewater lagoon system treating urban wastewatrers of the village of Guardamar del Segura (Alicante, Spain). Classical microbiological technology to detect salmonellae was used, including pre-enrichment, enrichment, selective media plating and biochemical and serological confirmation. Water was physicochemically characterized according to COD, SS, temperature, pH and dissolved oxygen. The selective migration step through Rappaport-Vassiliadis semisolid agar medium was essential for the consistent detection of Salmonella in the different lagoon effluents. Total and fecal coliform levels of up to 105-106 MPN/100 ml were detected in the final effluent. High coliphage concentrations of 103-104 pfu/ml were also found in the effluent waters. Salmonella was always detected in 100 ml samples and eventually reached an order of value of 103 MPN/100 ml. Total coliform reduction was higher in the anaerobic ponds whereas fecal coliforms were more efficiently eliminated in the facultative (mostly “anoxic”) lagoons. Coliphage reduction was higher in the facultative lagoons when compared to the anaerobic ponds. On many occasions, no reduction or eventual increment of the concentration of salmonellae was detected in the effluents from the anaerobic ponds compared to concentrations of the patohogen in the influent raw wasterwaters. The possibility exists for a capacity of Salmonella to multiply in the anoxic phase of the wastewater treatment, but the presence of microorganisms in raw sewage waters which could maskSalmonella detection with the enrichment methodology employed cannot be ruled out.


2002 ◽  
Vol 68 (4) ◽  
pp. 1631-1638 ◽  
Author(s):  
A. Leclercq ◽  
C. Wanegue ◽  
P. Baylac

ABSTRACT A 24-h direct plating method for fecal coliform enumeration with a resuscitation step (preincubation for 2 h at 37 ± 1°C and transfer to 44 ± 1°C for 22 h) using fecal coliform agar (FCA) was compared with the 24-h standardized violet red bile lactose agar (VRBL) method. FCA and VRBL have equivalent specificities and sensitivities, except for lactose-positive non-fecal coliforms such as Hafnia alvei, which could form typical colonies on FCA and VRBL. Recovery of cold-stressed Escherichia coli in mashed potatoes on FCA was about 1 log unit lower than that with VRBL. When the FCA method was compared with standard VRBL for enumeration of fecal coliforms, based on counting carried out on 170 different food samples, results were not significantly different (P > 0.05). Based on 203 typical identified colonies selected as found on VRBL and FCA, the latter medium appears to allow the enumeration of more true fecal coliforms and has higher performance in certain ways (specificity, sensitivity, and negative and positive predictive values) than VRBL. Most colonies clearly identified on both media were E. coli and H. alvei, a non-fecal coliform. Therefore, the replacement of fecal coliform enumeration by E. coli enumeration to estimate food sanitary quality should be recommended.


1983 ◽  
Vol 29 (10) ◽  
pp. 1261-1269 ◽  
Author(s):  
W. J. Robertson ◽  
R. S. Tobin

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.


2003 ◽  
Vol 69 (8) ◽  
pp. 4884-4891 ◽  
Author(s):  
Kevin A. Hughes

ABSTRACT Factors affecting fecal microorganism survival and distribution in the Antarctic marine environment include solar radiation, water salinity, temperature, sea ice conditions, and fecal input by humans and local wildlife populations. This study assessed the influence of these factors on the distribution of presumptive fecal coliforms around Rothera Point, Adelaide Island, Antarctic Peninsula during the austral summer and winter of February 1999 to September 1999. Each factor had a different degree of influence depending on the time of year. In summer (February), although the station population was high, presumptive fecal coliform concentrations were low, probably due to the biologically damaging effects of solar radiation. However, summer algal blooms reduced penetration of solar radiation into the water column. By early winter (April), fecal coliform concentrations were high, due to increased fecal input by migrant wildlife, while solar radiation doses were low. By late winter (September), fecal coliform concentrations were high near the station sewage outfall, as sea ice formation limited solar radiation penetration into the sea and prevented wind-driven water circulation near the outfall. During this study, environmental factors masked the effect of station population numbers on sewage plume size. If sewage production increases throughout the Antarctic, environmental factors may become less significant and effective sewage waste management will become increasingly important. These findings highlight the need for year-round monitoring of fecal coliform distribution in Antarctic waters near research stations to produce realistic evaluations of sewage pollution persistence and dispersal.


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