Faecal Coliform Bacteria in Febros River (Northwest Portugal): Temporal Variation, Correlation with Water Parameters, and Species Identification

Febros river water was sampled weekly, during 35 successive weeks, and analyzed for microbiological (total coliforms, faecal coliforms, faecal streptococci and enterococci) and chemical-physical (ammonia and temperature) parameters. All microbiological parameters were highly correlated with each other and with ammonia, suggesting that the simultaneous determination of all variables currently in use in the evaluation of the microbiological quality of waters is probably redundant, and could be simplified, and that ammonia should be tested as a sentinel parameter of the microbiological pollution load of Febros river. From the strains isolated from positive tubes of the faecal coliforms test (multiple tube fermentation technique) and retested in this assay, Escherichia coli, Klebsiella oxytoca and Klebsiella pneumoniae subsp. pneumoniae strains were positive, indicating that the faecal coliforms test is not totally specific for Escherichia coli, and can detect other bacteria. Considering that these Klebsiella spp. are not necessarily of faecal origin, it was concluded that the faecal coliforms test can overestimate true faecal pollution. From the strains isolated from positive tubes of the faecal coliforms procedure, only Escherichia coli strains were clearly positive in the β-D-glucuronidase test. All other species were negative or very weakly positive, suggesting that the assay of the β-D-glucuronidase activity is less prone to false positives than the faecal coliforms test in the quantification of Escherichia coli in environmental waters.     

Chlorination in a wastewater treatment plant: acute toxicity effects of the effluent and of the recipient water body

This study investigates the impact of wastewater treatment plant (WWTP) effluent on the toxicity of the recipient water body and the effectiveness of the disinfection treatment applied (sodium hypochloride) to assure the compliance of both microbiological and toxicological emission limits. No toxicity was found in the majority of samples collected from the recipient river, upstream and downstream of the WWTP, using three different toxicity tests (Vibrio fischeri, Daphnia magna, and Pseudokirchneriella subcapitata). Only three samples presented toxic unit (TU) values with V. fischeri, and one presented TU with P. subcapitata. The influent toxicity ranged from slightly toxic to toxic (TU = 0.68–4.47) with V. fischeri, while only three samples presented TU values with the other tests. No toxicity was found in the absence of chlorination, while the mean toxicity was 3.42 ± 4.12 TU with chlorination in the effluent. Although no toxicity or very slight toxicity was found in the receiving water, its residual toxicity was higher than the US EPA Quality Standard in two samples. Escherichia coli concentration had a lower mean value in the chlorinated effluent: 13,993 ± 12,037 CFU/100 mL vs. 62,857 ± 80,526 CFU/100 mL for the not chlorinated effluent. This difference was shown to be significant (p < 0.05). E. coli in ten chlorinated samples was higher than the limit established by European and Italian Legislation. The mean highest trihalomethanes (THMs) value was found in the influent samples (2.79 ± 1.40 μg/L), while the mean highest disinfection by-products (DBPs) was found in the effluent samples (1.85 ± 2.25 μg/L). Significant correlations were found between toxicity, sodium hypochlorite, THMs, DBPs, E. coli, and residual chlorine. In conclusion, this study highlighted that the disinfection of wastewater effluents with sodium hypochlorite determines the increase of the toxicity, and sometimes is not enough to control the E. coli contamination.     

Seasonal and spatio-temporal distribution of faecal-indicator bacteria in Tyume River in the Eastern Cape Province, South Africa

We assessed the incidence of faecal-indicator bacteria in Tyume River over a 12-month period between August 2010 and July 2011. Total coliforms, faecal coliforms and enterococci were determined by the membrane filtration method. Total coliforms were detected in counts ranging from 2.1?×?10² to 3.4?×?10⁴?CFU/100 ml. Faecal coliform counts ranged from 1?×?10² to 1.6?×?10⁴?CFU/100 ml while enterococci counts were in the range of 3.3?×?10¹ to 5.1?×?10³?CFU/100 ml. Indicator bacteria counts increased from upstream to downstream sampling sites. Counts of indicator bacteria at all sites were significantly affected by seasonal changes. The bacteriological qualities of the river water were poor, exceeding the guideline of 200 CFU/100 ml and 33 CFU/100 ml for faecal coliforms and enterococci, respectively, for recreational water. Faecal coliform counts also exceeded the 1,000 CFU/100 ml guideline for water used in fresh produce irrigation. Microbial source tracking results showed that faecal pollution was predominantly of human origin during spring at all sampling sites. During other seasons, human faecal pollution was largely confined to midstream and downstream sampling sites. Generally, the presence of faecal-indicator bacteria in the river water samples suggests faecal pollution of this freshwater resource, raising the possibility of the presence of pathogenic microorganisms in the water and a threat to public health.     

Evaluation of simple microbiol tests for detection of fecal coliforms directly at 44.5 degrees C

Simple microbial test comprising H₂S paper strip test,presence-absence (PA) test, and fluorogenic brila broth (BB)test performed directly at 44.5 °C were evaluated andcompared with the standard most probable number (MPN) method fordetection of fecal coliforms in 173 drinking water sources. BBand PA test were comparable with standard MPN method, whereas,poor compliance was noted for H₂S test. PA test whencompared with standard MPN test only 15%; disagreement wasdetected, whereas, highest disagreement of 40%; was observed incase of H₂S test. BB test was found to be highly sensitiveas only 7.8% disagreement with that of standard MPN test wasfound. Three hundred cultures obtained from positive tests wereidentified in order to evaluate the specificities of test usedin detection of fecal indicator Escherichia coli. BB testwas also found highly specific in detection of indicatororganism as compared to PA and H₂S test. Among theorganisms isolated from BB test 84.4%; of them were identifiedas E. coli as compared to 43.4 and 33.3 in PA and H₂Stest, respectively. The low incidence of recovery of E.coli (18.1%) for the standard MPN method places doubt on thevalidity of its application in tropical areas. The result ofthis investigation suggest that BB performed directly at 44.5 °C could be suitable cost effective test to assess themicrobiological quality of drinking water in India and other tropical countries.     

Physicochemical and microbiological assessment of recreational and drinking waters

The present study was aimed to make an assessment of health risk due to pollution and human pathogenic bacteria associated with the recreational and drinking water sources in twin densely populated holy Indian cities Ayodhya and Faizabad. Though physicochemical studies revealed that the water available in the area is under recommended limits for human use, it is unsafe on account of poor microbiological quality of surface and ground water in the region. The most probable number (MPN) test results revealed the preponderance of ≥2,400 total coliforms (TC) (100 ml)^− 1 in river, pond, dug well and kund waters. Contrary to that, 94% tube wells, 32% hand pumps and 25% piped supply water were under safe limits having <3 TC (100 ml)^− 1. The shallow depth (~40 ft), water logging and presence of septic tanks in the near vicinity are the possible reasons of poor microbial quality of hand pump drinking water. The municipal supply water passes along sewage line where loose connections and/or cracks in pipe lead to mixing and contamination. The significant best quality of tube well water evident from the absence of TC could be attributed to the depth of well ≥150 ft and usually their location away from the habitation. A total of 263 bacteria from 186 water samples were isolated, and at least five genera of enteric bacteria from various water sources were identified morphologically and biochemically as Escherichia coli, Klebsiella sp., Enterobacter sp., Shigella sp. and Salmonella sp. The serotyping of 72 E. coli and 36 Salmonella sp. revealed 51 as E. coli O157 and 20 as Salmonella sp. The presence of enteric pathogens in water sources pose threat to human health and therefore call for immediate remedial measures.     

Applicability of universal Bacteroidales genetic marker for microbial monitoring of drinking water sources in comparison to conventional indicators

Water quality monitoring is essential for the provision of safe drinking water. In this study, we compared a selection of fecal indicators with universal Bacteroidales genetic marker to identify fecal pollution of a variety of drinking water sources. A total of 60 samples were collected from water sources. The microbiological parameters included total coliforms, fecal coliforms, Escherichia coli and fecal streptococci as the fecal indicator bacteria (FIB), Clostridium perfringens and H₂S bacteria as alternative indicators, universal Bacteroidales genetic marker as a promising alternative fecal indicator, and Salmonella spp., Shigella spp., and E. coli O157 as pathogenic bacteria. From 60 samples analyzed, Bacteroidales was the most frequently detected indicator followed by total coliforms. However, the Bacteroidales assay failed to detect the marker in nine samples positive for FIB and other alternative indicators. The results of our study showed that the absence of Bacteroidales is not necessarily an evidence of fecal and pathogenic bacteria absence and may be unable to ensure the safety of the water. Further research, however, is required for a better understanding of the use of a Bacteroidales genetic marker as an indicator in water quality monitoring programs.     

Efficiency of Modified H2S Test for Detection of Faecal Contamination in Water

Faecal contamination is a major causative factor for incidence of water borne infectious diseases. Certain hydrogen sulfide (H₂S) producing enteric bacteria such as Salmonella sp. and Citrobacter sp., assosiated with coliforms, have been considered for rapid detection of recent faecal contamination in water. The basic H₂S test medium, modified by adding 0.25 gm/L of L-cystine HCl, was examined for its efficiency with 90 water samples collected from 40 pipe supplies, 20 open wells, 15 hand pumps and 15 different surface water bodies (river, streams and ponds). Sterilized modified culture medium in glass vials was inoculated with 100 mL of each sample and incubated at 20, 25, 30, 35 and 44 ^∘C for 18, 24, 42, 48, 66 and 72 h. Blackening of content in incubated vials was considered positive. For comparison, most probable number (MPN) of coliform and faecal coliform per 100 mL was also estimated in each sample by multiple tube fermentation (MTF) method. H₂S positive result was exhibited by 78% of samples. Coliform (> 10) and faecal coliform/100 mL were also detected in 59% of samples. Maximum H₂S positive results (100%) were found with well and surface water samples incubated at 30, 35 and 44 ^∘C for 18 h. Coliform (> 10) and faecal coliform/100 mL were also detected in most of these samples. Pipe supplies (60%) and hand pumps (73%) also exhibited considerable H₂S production. Coliforms and faecal coliforms were also found in significant number of these samples. Thus, the modified H₂S test may prove a useful alternative indicator of faecal contamination for water quality surveillance and screening of large number of water samples in short duration, particularly during any outbreak of water borne disease among rural population.     

Comparative study of fluorogenic and chromogenic media for specific detection of environmental isolates of thermotolerant Escherichia coli

In a field study 78 water samples were analysed employingFluorocult Brilla Broth (BB) and its performance was comparedwith standard MPN procedure. Out of 78 water samples analysed 56(71.7%) samples yielded positive reactions in BB whereas, 50(64.1%) samples were positive by standard fecal coliform test.A comparative study of fluorogenic and chromogenic mediacontaining substrate -D glucuronide for specificdetection of environmental isolates of 313 thermotolerant E.coli has been undertaken. Five fluorogenic media wereused: Fluorocult MacConkey agar (MCA), Fluorocult ECD agar(ECD), Fluorocult VRB agar (VRB), Fluorocult E. coli0157:H7 agar (ECH7) and Fluorocult Brilla Broth (BB) andChromogenic Chromocult agar (CCA). BB and CCA were found to behighly specific and sensitive media to detect E. coli asall E. coli yielded positive reaction on them. On ECH7 andECD agar 67.5 and 64.9 of E. coli isolates gave positivereaction, respectively. Low sensitivity was observed in case ofMCA and VRB agar in detecting E. coli. The performance ofBB appears to be better when compared with standard MPNprocedure employing MacConkey broth/Brilliant green bile brothin detecting E. coli in drinking water.     

Serogroups of Escherichia coli from Drinking Water

Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli, ETEC) and 0113 (Shiga-toxin producing E. coli, STEC). All the pathogenic serotypes showed resistance to bacitracin and multiple heavy metal ions. Resistance to streptomycin and co-trimazole was detected in two strains whereas resistance to cephaloridine, polymixin-B and ampicillin was detected in one strain each. Transfer of resistances to drugs and metallic ions was observed in 9 out of 12 strains studied. Resistances to bacitracin were transferred in all nine strains. Among heavy metals resistance to As³⁺ followed by Cr⁶⁺ were transferred more frequently.     

Water quality status of dugouts from five districts in Northern Ghana: implications for sustainable water resources management in a water stressed tropical savannah environment

This study was primarily aimed at investigating the physicochemical and microbial quality of water in 14 such dugouts from five districts in the northern region of Ghana. Results obtained suggest that except for colour, turbidity, total iron and manganese, many physicochemical parameters were either within or close to the World Health Organisation’s acceptable limits for drinking water. Generally, colour ranged from 5 to 750 Hz (mean 175 Hz), turbidity from 0.65 to 568 nephelometric turbidity units (NTU; mean 87.9 NTU), total iron from 0.07 to 7.85 mg/L (mean 1.0 mg/L) and manganese from 0.03 to 1.59 mg/L (mean 0.50 mg/L). Coliform counts in water from all the dugouts in both wet and dry seasons were, however, above the recommended limits for drinking water. Total and faecal coliforms ranged from 125 to 68,000 colony forming units (cfu)/100 mL (mean 10,623 cfu/100 mL) and <?1 to 19,000 cfu/100 mL (mean 1,310 cfu /100 mL), respectively. The poor microbial quality, as indicated by the analytically significant presence of coliform bacteria in all samples of dugout water, strongly suggests susceptibility and exposure to waterborne diseases of, and consequent health implications on, the many people who continuously patronise these vital water resources throughout the year. In particular, more proactive sustainable water management options, such as introduction to communities of simple but cost-effective purification techniques for water drawn from dugouts for drinking purposes, education and information dissemination to the water users to ensure environmentally hygienic practices around dugouts, may be needed.     

Environmental pollutions impacts on the bacteriological and physicochemical quality of suburban and rural groundwater supplies in Marrakesh area (Morocco)

This study scrutinized bacteriological and chemical quality of groundwater supplies of Marrakesh (Morocco) within a year. It assessed the influence of some chemical factors on fecal and opportunistic pathogenic bacterial communities. The annual average densities of fecal coliforms, fecal streptococci and Pseudomonas aeruginosa were respectively: 1891 colony forming units (CFU)/100 mL, 1246 CFU/100 mL and 206 CFU/100 mL. The total occurrence of these bacteria during the period of study was 94%. Detectable non-O1 Vibrio cholerae was present in 81% of samples and the mean abundances ranged from 0 to 11100 MPN/100 mL. Significant correlations between fecal coliforms and streptococci and between fecal coliforms and non-O1 V. cholerae (p < 0.01) were found. Fecal coliforms can be used to detect the presence of non-O1 V. cholerae in this groundwater. These well waters were greatly mineralized, hard, salt with high concentrations of nitrogenous ions and major elements (Ca(2+), Na(+), Cl(-), SO(2-)(4) and K(+)). Most of chemical parameters were relatively steady with time except for calcium, ammonium, nitrites and organic matter which were seasonally influenced. The degree of correlation between chemical parameters and the abundances of isolated bacteria is heterogeneous. The concentrations of calcium and nitrites favored (p < 0.01) the abundance of fecal coliforms and streptococci, but reduced P. aeruginosa abundances. Calcium, salinity, chlorides, nitrites and nitrates tests can be used for screening in situ when the laboratory facilities are limited. This work is expected to assist local authorities in developing plans and actions to reduce the pollution to acceptable levels.     

荧光法快速测定水中粪大肠菌群

为研究荧光法测定水中粪大肠菌群的适用性,在6家实验室使用荧光法对粪大肠菌群的标准菌株和实际水样进行测定,并与多管发酵法进行比对。结果表明:6家实验室对标准菌株的监测结果均在误差范围内,实验室内相对误差为-2. 75%～1. 71%,准确度较高;对3个不同浓度实际水样进行精密度测定,实验室内相对标准偏差分别为1. 30%～3. 93%、1. 94%～4. 72%、1. 88%～4. 54%,实验室间的相对标准偏差分别为1. 14%、1. 59%、1. 72%,精密度较高;用荧光法与多管发酵法同时测定实际水样,2种方法测试结果线性相关性良好且变化趋势相同,对测试数据进行t检验,2种方法测试结果无显著差异。     

Assessment of ground water quality for drinking purpose, District Nainital, Uttarakhand, India

The ground water quality of District Nainital (Uttarakhand, India) has been assessed to see the suitability of ground water for drinking and irrigation applications. This is a two-part series paper and this paper examines the suitability of ground water including spring water for drinking purposes. Forty ground water samples (including 28 spring samples) were collected during pre- and post-monsoon seasons and analyzed for various water quality constituents. The hydrochemical and bacteriological data was analyzed with reference to BIS and WHO standards and their hydrochemical facies were determined. The concentration of total dissolved solids exceeds the desirable limit of 500 mg/L in about 10% of the samples, alkalinity values exceed the desirable limit of 200 mg/L in about 30% of the samples, and total hardness values exceed the desirable limit of 300 mg/L in 15% of the samples. However, no sample crosses the maximum permissible limit for TDS, alkalinity, hardness, calcium, magnesium, chloride, sulfate, nitrate, and fluoride. The concentration of chloride, sulfate, nitrate, and fluoride are well within the desirable limit at all the locations. The bacteriological analysis of the samples does not show any sign of bacterial contamination in hand pump and tube-well water samples. However, in the case of spring water samples, six samples exceed the permissible limit of ten coliforms per 100 ml of sample. It is recommended that water drawn from such sources should be properly disinfected before being used for drinking and other domestic applications. Among the metal ions, the concentration of iron and lead exceeds the permissible limit at one location whereas the concentration of nickel exceeds the permissible limit in 60 and 32.5% of the samples during pre- and post-monsoon seasons, respectively. The grouping of samples according to their hydrochemical facies indicates that majority of the samples fall in Ca–Mg–HCO₃ hydrochemical facies.     

水质标准中指示微生物的发展及现状

饮用水病原微生物污染是公共卫生面临的主要威胁之一,微生物监测在水质监测中的必要性日益受到人们的认可。在实际工作中,一般是通过检测指示微生物间接反映病原微生物的存在。通过调研国内外各组织、机构颁布的水质标准发现,近年来,我国环境质量标准和污染物排放标准中对于指示微生物的选择有从总大肠菌群向粪大肠菌群和大肠埃希氏菌(E.coli)转变的趋势,而美国环保署、欧盟、世界卫生组织、澳大利亚国家健康与医疗研究委员会等根据最新的流行病学证据,强调了大肠埃希氏菌(E.coli)、肠球菌(Enterococci)与粪便污染的相关性更强,可用于替代大肠菌群。建议我国在后续水质标准中对微生物指标进行增补修订时,参考国外经验,形成集成多种指示微生物与多种特定病原体的监测指标体系,以更好地保护环境功能和民众健康。     

Development of a PCR protocol for the detection of Escherichia coli O157:H7 and Salmonella spp. in surface water

Escherichia coli O157:H7 and Salmonella are pathogenic microorganisms that can cause severe gastrointestinal illness in humans. These pathogens may be transmitted in a variety of ways, including food and water. The presence of Salmonella and E. coli O157:H7 in surface waters constitutes a potential threat to human health when used for either drinking or recreation. As with most waterborne pathogens, Salmonella and E. coli O157:H7 are difficult to detect and enumerate with accuracy in surface waters due to methodological limitations. The aim of this study was to develop a protocol for the detection of Salmonella spp., E. coli O157:H7 and E. coli virulence genes (stx ₁, stx ₂ and eae) in water using a single enrichment step and PCR. In spiked water samples, PCR results showed high sensitivity (<3 CFU/L) for both microorganisms. The protocol developed in this study has been applied in different surface waters in association with microbiological and physical analysis. The frequency of PCR positive samples was 33% for Salmonella and 2% for E. coli O157:H7 producing intimin (eae) and Shiga-like toxin I (stx ₁). Moreover, the finding of amplicons corresponding to eae and stx ₁ genes in the absence of E. coli O157:H7 suggested the possible presence of other pathogenic bacteria that carry these genes (e.g. EHEC, Shigella strains). The results obtained showed that the developed protocol could be applied as a routine analysis of surface water for the evaluation of microbiological risks.     

Relative proportions of <Emphasis Type="Italic">E. coli</Emphasis> and <Emphasis Type="Italic">Enterococcus spp.</Emphasis> may be a good indicator of potential health risks associated with the use of roof harvested rainwater stored in tanks

A total of 285 water samples were collected from 71 roof harvested rainwater tanks from four villages in different provinces over a two-year (2013–2014) period during the early (October to December) and late (January to March) rainy season. Water quality was evaluated based on Escherichia coli, faecal coliforms and Enterococcus spp. prevalence using the IDEXX Quanti-Tray quantification system. Real-Time PCR was used to analyse a subset of 168 samples for the presence of Shigella spp., Salmonella spp. and E. coli virulence genes (stx1, stx2 and eaeA). Escherichia coli were detected in 44.1% of the samples, Enterococcus spp. in 57.9% and faecal coliforms in 95.7%. The most prevalent E. coli concentrations in harvested rainwater were observed in 29.1% of samples and 22.5% for Enterococcus spp. and, were within 1–10 cfu/100 ml and 10–100 cfu/100 ml, respectively, whereas those for faecal coliforms (36.6%) were within 100–1000 cfu/100 ml. On average 16.8% of the samples had neither E. coli nor Enterococcus spp. detected, while 33.9% had only Enterococcus spp. and 23.7% had only E. coli. E. coli and Enterococcus spp. were detected together in 25.5% of the samples. Evaluation of samples for potential pathogenic bacteria showed all tested samples to be negative for the Shigella spp. ipaH gene, while five tested positive for Salmonella ipaB gene. None of the samples tested positive for the stx1 and stx2 genes, and only two tested positive for the eaeA gene. These findings are potentially useful in the development of a simplified risk assessment strategy based on the concentrations of indicator bacteria.     

遂宁城乡集中式饮用水水源地钡分布特征及健康风险评价

为考察遂宁市辖区内集中式饮用水水源地污染物钡的分布特征和健康风险水平,通过电感耦合等离子体原子发射光谱法对研究区域内市级、县级和乡镇级所有在用的56个集中式饮用水水源地钡的浓度进行分析检测,借助空间分析与统计分析的结果,探讨了其空间分布和浓度差异,并利用环境健康风险评价模型,对不同类型水源地钡的健康风险进行了评价。结果表明,38个地表水水源地钡的浓度范围为0.065~0.180 mg/L,均值为0.110 mg/L;18个地下水水源地钡的浓度范围为0.027~0.370 mg/L,均值为0.130 mg/L。地表水与地下水水源地间钡的浓度差异具有统计学意义(P0.05),钡的空间分布也存在不同程度的差异性。各水源地中的钡经饮用和皮肤暴露两种途径对成人和儿童所引起的非致癌风险值为1.34×10~(-8)~1.62×10~(-8),远低于推荐的最大可接受风险水平(1.0×10~(-6)),各水源地因污染物钡导致的非致癌风险极低。     

Estimating the Microbial Risk of E. coli in Reclaimed Wastewater Irrigation on Paddy Field

Microbial risk was quantified to assess human health risk as a result of exposure to E. coli in reclaimed wastewater irrigation. Monitoring data on E. coli were collected from pond water in paddy rice plots during the growing season. Five treatments were used and each was triplicated to evaluate the changes in E. coli concentrations in experiments performed in 2003 and 2004. The Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion among farmers and neighboring children. A Monte Carlo simulation (10,000 trials) was conducted to estimate the risk associated with uncertainty. In this study, risk values ranged from 10⁻⁴ to 10⁻⁸. UV-disinfected irrigation water showed a lower risk value than others, and its level was within the range of the actual paddy rice field with surface water. Agricultural activity was thought to be safer after 1–2 days, when the paddy field was irrigated with reclaimed wastewater. Also, children were found to have a greater risk of infection with E. coli. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of wastewater reuse in paddy rice culture.     

Characterization and statistical modeling of bacterial (Escherichia coli) outflows from watersheds that discharge into southern Lake Michigan

Two watersheds in northwestern Indiana were selected for detailed monitoring of bacterially contaminated discharges (Escherichia coli) into Lake Michigan. A large watershed that drains an urbanized area with treatment plants that release raw sewage during storms discharges into Lake Michigan at the outlet of Burns Ditch. A small watershed drains part of the Great Marsh, a wetland complex that has been disrupted by ditching and limited residential development, at the outlet of Derby Ditch. Monitoring at the outlet of Burns Ditch in 1999 and 2000 indicated that E. coli concentrations vary over two orders of magnitude during storms. During one storm, sewage overflows caused concentrations to increase to more than 10,000 cfu/100 mL for several hours. Monitoring at Derby Ditch from 1997 to 2000 also indicated that E. coli concentrations increase during storms with the highest concentrations generally occurring during rising streamflow. Multiple regression analysis indicated that 60% of the variability in measured outflows of E. coli from Derby Ditch (n = 88) could be accounted for by a model that utilizes continuously measured rainfall, stream discharge, soil temperature and depth to water table in the Great Marsh. A similar analysis indicated that 90% of the variability in measured E. coli concentrations at the outlet of Burns Ditch (n = 43) during storms could be accounted for by a combination of continuously measured water-quality variables including nitrate and ammonium. These models, which utilize data that can be collected on a real-time basis, could form part of an Early Warning System for predicting beach closures.     

Bacterial contamination and health risks of drinking water from the municipal non-government managed water treatment plants

Water quality and bacterial contamination from 18 drinking water municipal plants in three locations at Giza governorate were investigated. The average total count of bacteria detected after four stages of treatments in the investigated plants was 32 CFU/1 mL compared to 2330 cfu/mL for raw water, with a reduction percentage of 98.6. Although there is a relatively high removal percent of bacterial contamination from the water sources, however, several bacterial pathogens were identified in the produced water prepared for drinking including Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Shigella spp. After 3 days of water incubation at 30 °C, the amount of bacterial endotoxins ranged from 77 to 137 ng/mL in the water produced from the municipal plants compared to 621–1260 ng/mL for untreated water. The main diseases reported from patients attending different clinics and hospitals during summer 2014 at the surveyed locations and assuredly due to drinking water from these plants indicated that diarrheas and gastroenteritis due to E. coli and Campylobacter jejuni constituted 65.7% of the total patients followed by bacillary dysentery or shigellosis due to Shigella spp. (7.9%) and cholera due to Vibrio cholera (7.2%). There was an increase in serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) as well as urea and creatinine values of guinea pigs consuming water produced from the non-governmental plants for 6 months indicating remarkable liver and kidney damages. Histological sections of liver and kidney from the tested animal revealed liver having ballooning degeneration of hepatocytes and distortion and fragmentation of the nuclei, while the section of the kidney showed irregularly distributed wrinkled cells, degenerated Bowman’s capsule, congested blood vessels, and inflammatory cells.