Bacteriological aspects of pollution in the Jukskei — Crocodile river system in the Transvaal,South Africa

A combination of routine methods of bacteriological analysis has been utilised to investigate conditions in a river system which in part is subject to the effects of the discharge of appreciable quantities of sewage effluents which, during the dry season, may constitute the major part of the total flow. Other parts of the river system are free from gross pollution, and results obtained from these sections served as a basis for comparison. The river system is capable of coping with most of the detrimental effects of direct faecal pollution in varying form. But under no circumstances do these findings imply that the river system is capable of dealing with unrestricted quantities of sewage effluents for an unlimited period of time. Industrial pollution of varying character has been found to have little, if any, effect on bacterial numbers. The effect these effluents may have on the composition of the bacterial population as a whole has not been investigated, but this influence would be of local significance only. The methods used and the interpretations applied to the results seem to constitute a valuable instrument in the detailed study and assessment of bacteriological quality of the waters in a natural river system which is subject to severe pollution from sewage and industrial effluents of varying character.     

Seasonal changes in the microbial population of the water column and sediments of the Ongagawa River,northern Kyushu,Japan

The total viable count, population density of Escherichia coli and coliform bacteria, and nitrogen in the microbiomass (microbiomass-N) in sediments were monitored monthly at 12 points in the Ongagawa River basin from June 2002 to May 2006. The measurement of the sediment microbiomass-N was used for evaluation of the sediment’s microbial population in the river ecosystem. An extraordinarily high population of E. coli was observed during the season when there was stagnant water in the basin, with a high population and an insufficient drain diffusion system, and, thus hydrological water control is indispensable to prevent rapid E. coli growth. Microbiomass-N in sediments showed a negative correlation or independent fluctuation in relation to the bacterial population in the water column of the river. Seasonal changes in extracted nitrogen (N) in river sediments did not show correspondence with microbiomass-N in sediments. The microbiomass-N in sediments changed independently of the bacterial population in the river water, indicating that the high population of bacteria in the water does not lead to a high microbial population in river sediments. Ordination of the microbial parameters by canonical correspondence analysis (CCA) showed that microbiomass-N in sediments was quite different from other parameters. Relatively higher H⁺ (lower pH), PO₄ ³⁻ concentration and dissolved oxygen (DO) were the determinant parameters of higher microbiomass-N in sediments. A relative microbial abundance between the water column and sediments as well as each of the microbial populations in the water column and sediments could be a quantitative parameter for evaluating the biochemical processes of stream water.     

Coliforms as a measure of sewage contamination of the River Zambezi

The effect of releasing untreated sewage from Victoria Falls Town into the Zambezi river was determined by bacteriological examination of water samples collected upstream of Victoria Falls and for 22 km downstream. Most probable numbers of faecal coliforms and Escherichia coli were estimated. Water upstream of the falls, on the Zimbabwe side of the river, contained between seven and 130 E. coli per 100 ml. This section of the river was free from major sources of faecal pollution. Below the falls, but before the Victoria Falls Town sewage outfall, numbers of E. coli were between 1.8 X 10(2) and 1.4 X 10(4)/100 ml, indicating the existence of a sewage discharge other than that from Victoria Falls Town. The river was also highly polluted from the Victoria Falls Town sewage outfall to a point 18.6 km downstream. The highest E. coli count was 3.3 X 10(4)/100 ml and declined slowly to 1.4 X 10(3)/100 ml 18.6 km downstream of the outfall.     

Pre- and post-impoundment studies (1978–1982) in the Volta River below the Akosombo Dam with particular emphasis on the microbiology

A four year's survey of the Volta River below the Akosombo Dam to determine the distributional pattern and activities of different bacterial groups during pre- and post-impoundment of the river at Kpong is reported. The bacterial numbers were high and showed variations in all the stations. Relatively low bacterial numbers were observed in the upper reaches. The different bacterial groups followed approximately the same pattern over the entire length of the river. Industrial and domestic wastes slightly affected the quality of the water. The entire system was well oxygenated. During pre-impoundment studies the oxygen condition improved as the water flows downstream. Early post-impoundment studies showed a decrease in dissolved oxygen concentration around the middle reaches and an increase below the Kpong Dam. An emergence of Ceratophyllum demersum, Potamogeton octandrus, Vallisneria aegyptica and aquatic snails, which carry bilharzia parasites, was observed in the Kpong Headpond during post-impoundment studies. There was an extensive growth of submerged aquatic plants in the lower reaches.     

Impacts of cage culture on physico-chemical and bacteriological water quality in Lake Volta,Ghana

The effects of cage fish farming on physico-chemical and bacteriological water quality in Lake Volta, Ghana, were investigated in 2013–2014. Farmed and unfarmed (control) areas of the lake were selected for monitoring. Nutrients, temperature, dissolved oxygen, conductivity, turbidity, pH, total coliforms, Pseudomonas and Vibrio spp. in the water were monitored monthly. Analyses of the water samples were carried out according to standard procedures. Physico-chemical quality of the water in both farm and control sites were within ranges typical of minimally impacted water and did not vary significantly between the two contrasting sites. The bacteriological analysis, however, revealed contamination of the lake water by fish farming. The bacterial counts at the farmed sites were significantly higher (p < 0.05) than those of the control sites, with figures at the farmed sites ranging from 132 to 1 708 cfu 100 ml?1 for total coliforms, 514 to 5 170 cfu 100 ml?1 Pseudomonas spp. and 14 to 516 cfu 100 ml?1 for Vibrio spp. The results suggested that cage fish farming has increased bacterial loads in the lake water, but has had minimal impact on its physico-chemical quality.     

Influence of Physicochemical Parameters on the Abundance of Coliform Bacteria in an Industrial Site of the Hooghly River, India

Industrial effluents from jute, paper, pulp mills and sewage from households are regularly discharged into the Hooghly River. It generates a potential risk for both humans and animals of the area concerned. In the present study, water quality of the Hooghly River passing by the site of a growing township (Naihati, North 24 Parganas, West Bengal, India) was assessed throughout the year 2010 on the basis of the data collected on the physicochemical and microbiological parameters. The water samples collected on each month revealed the presence of higher amount of coliform bacteria, Streptococcus sp. and Escherichia coli, than the standard limit. Different physicochemical parameters like chemical oxygen demand, biological oxygen demand, dissolved oxygen (DO), total suspended solids, total dissolved solids (TDS), total hardness, alkalinity, chlorinity, nitrate and nitrite of the water at the sampling sites were found to be considerably higher than the levels standardized by WHO (2006). It was found that the relative abundance of Streptococcus and E. coli was influenced by two independent variables (water quality parameters), namely, DO and TDS. The abundance of coliform bacteria in the water sample warrants the adoption of proper measures to reduce the pollution level at the point source on way of scientific disposal of industrial effluents.     

Coliforms as a measure of sewage contamination of the River Zambezi

The effect of releasing untreated sewage from Victoria Falls Town into the Zambezi river was determined by bacteriological examination of water samples collected upstream of Victoria Falls and for 22 km downstream. Most probable numbers of faecal coliforms and Escherichia coli were estimated. Water upstream of the falls, on the Zimbabwe side of the river, contained between seven and 130 E. coli per 100 ml. This section of the river was free from major sources of faecal pollution. Below the falls, but before the Victoria Falls Town sewage outfall, numbers of E. coli were between 1.8 × 10² and 1.4 × 10⁴/100 ml, indicating the existence of a sewage discharge other than that from Victoria Falls Town. The river was also highly polluted from the Victoria Falls Town sewage outfall to a point 18.6 km downstream. The highest E. coli count was 3.3 × 10⁴/100 ml and declined slowly to 1.4 × 10³/100 ml 18.6 km downstream of the outfall.     

灞河城市段浮游生物群落结构时空变化及其与环境因子的关系

为了解灞河城市段浮游生物群落结构及其与环境因子之间的关系,于2016年9月至2017年7月每2个月进行一次采样分析。调查期间共鉴定出浮游植物7门63属,其中绿藻门种类数最多(34.9%),其次为硅藻门(30.2%);浮游动物4类45种,以轮虫(48.9%)和原生动物(24.4%)为主。浮游植物和浮游动物的丰度分别为0.73×10~4—98.5×10~4个/L和20—1084个/L,在时空分布上均呈现下游高于上游的趋势,峰值均出现在夏季。根据水体透明度、溶解氧、总磷、总氮、高锰酸盐指数和重金属等理化指标、浮游生物丰度、Shannon-Wiener多样性指数和Margalef丰富度指数对灞河城市段水质状况进行综合评价,结果显示,所研究流域总体为中污状态,上游景观河道内的水生植物对水体具有一定的修复能力。典范对应分析表明,水温、总氮、pH、溶解氧和汞是浮游植物群落分布的主要影响因子;影响浮游动物群落分布的主要因子为水温、总氮、总磷、叶绿素a和汞。     

Bacterial pollution of Messina coastal waters: a one year study

A year's monitoring of faecal pollution of marine coastal waters surrounding Messina was carried out in 1996/97. The distribution of faecal coliforms was evaluated in 15 stations located along the Sicilian coastline, sampled monthly in coincidence of the two opposing current phases ("montante" and "scendente" currents) which characterise the Straits of Messina. The data obtained provided a complete picture of hygienic-sanitary conditions of the area and highlighted the presence of heavily polluted sites in correspondence with river outflows. Higher bacterial counts were associated with lower salinity values and higher ammonia concentrations; over an annual study, they occurred during the coldest months, showing the negative impact of continental water inputs on the bacteriological quality of coastal waters.     

REPLY TO COMMENTS BY DR D H R HELLWIG ON PAPERS BY J.U. GROBBELAAR,M.K. SEELY & O.B. KOK

The aim of this study was to assess and compare the water quality of the Gwebi and Mukuvisi Rivers, on the basis of selected physicochemical variables and macroinvertebrate community structure. Five sites where selected on both rivers and these were sampled on three separate occasions between January and July of 1998. The water variables measured were the concentrations of iron, chromium, zinc, lead, copper, manganese, chlorides, fluorides, sulphates, total phosphates, nitrates, ammonia, total dissolved salts, dissolved oxygen, biological oxygen demand, as well as pH, conductivity, temperature, water surface velocity and discharge. The concentration of most of the chemical variables was relatively similar along the course of the Gwebi River, but there were drastic increases in the levels of iron, chromium, copper, zinc, chlorides, fluorides, sulphates, and ammonia along the Mukuvisi River. The two rivers were different with respect to the physicochemical variables, with the exception of the first site on the Mukuvisi, which was similar to sites on the Gwebi River. This was because of the differences in the levels of human activities on the two rivers. Industrial, sewage and domestic pollution has had an adverse effect on the water quality of the Mukuvisi River. There was a sharp decline in the number of macroinvertebrate taxa along the Mukuvisi River. The lower reaches of the river where dominated by oligochaetes and Chironimidae larvae. Sample score classification of water quality based on the South African Scoring System Version 4 (SASS4) showed that most of the Mukuvisi river had poor quality water quality, whilst much of the Gwebi River had fair quality water. The HABS1 habitat assessment index was used to assess habitat quality at each site. Although much of the Mukuvisi recorded fair to good habitat scores and had generally higher habitat scores than sites on the Gwebi, the SASS scores were generally lower compared to those along the Gwebi. The sample scores and average score per taxon (ASPT) of the SASS4 showed that the Mukuvisi River was of much lower quality than the Gwebi. Both the sample score and ASPT were negatively and significantly (p<0.05) correlated to most of the physicochemical variables. The water quality variables accounted for 61.1% and 59.0% of the differences in the sample score and ASPT respectively. There was a marginal decrease in the Margalef and Shannon indices along the Gwebi River, but the Simpson's index remained relatively constant. Along the Mukuvisi River, there was a clear and distinct decrease in the magnitude of all three diversity indices, indicating decreasing macroinvertebrate community structure. The change in water physicochemical variables accounted for 61.3%, 69.2% and 87.2% of the changes in the Margalef, Shannon and Simpson's index respectively. The study provides evidence that the changes in macroinvertebrate community structure along the Mukuvisi River is due to decline in the water quality. On the Gwebi, water quality is not the main factor determining macroinvertebrate community structure.     

Bacterioplankton and Organic Carbon Dynamics in the Lower Mesohaline Chesapeake Bay

The mesohaline portion of the Chesapeake Bay is subject to annual summertime hypoxia and anoxia in waters beneath the pycnocline. This dissolved oxygen deficit is directly related to salinity-based stratification of the water column in combination with high levels of autochthonously produced organic matter and a very high abundance of metabolically active bacteria. Throughout the water column in the lower, mesohaline part of the bay, between the Potomac and Rappahannock rivers, near the southern limit of the mainstem anoxia, bacterial abundance often exceeded 10 × 10⁶ cells per ml and bacterial production exceeded 7 × 10⁹ cells per liter per day during summer. Bacterial biomass averaged 34% (range, 16 to 126%) of the phytoplankton biomass in summer. These values are equal to or greater than those found farther north in the bay, where the oxygen deficit is more severe. Seasonal variations in bacterial abundance and production were correlated with phytoplankton biomass (lag time, 7 to 14 days), particulate organic carbon and nitrogen, and particulate biochemical oxygen demand in spring; but during summer, they were significantly correlated only with dissolved biochemical oxygen demand. During summer, dissolved biochemical oxygen demand can account for 50 to 60% of the total biochemical oxygen demand throughout the water column and 80% in the bottom waters. There is a clear spring-summer seasonal shift in the production of organic matter and in the coupling of bacteria and autochthonous organic matter. The measurement of dissolved, microbially labile organic matter concentrations is crucial in understanding the trophic dynamics of the lower mesohaline part of the bay. The absolute levels of organic matter in the water column and the bacterial-organic carbon relationships suggest that a lower bay source of organic matter fuels the upper mesohaline bay oxygen deficits.     

东钱湖水体异养细菌的时空分布及其与环境影响因素和有机质的关系

为探究宁波东钱湖表层水体中异养细菌丰度的时空分布特征及其环境影响因素对可溶性有机质转化的影响, 实验采用主成分分析及多元逐步回归分析方法研究了三者之间的关系, 结果表明: 调查期间东钱湖表层水体中异养细菌丰度的季节分布特征为夏季>春季>冬季, 支流汇入口、码头或水上乐园区域水体中异养细菌丰度较高, 近岸人类活动带来的陆源污染是造成此分布特征的主要原因; 多元统计分析结果表明ST、DO、COD、Chla、DOM是制约宁波东钱湖表层水体中异养细菌分布的主要环境因素, 且ST、Chla、COD、DOM中的类芳香族蛋白质Ⅰ及类溶解性微生物代谢产物IV与异养细菌丰度呈显著正相关(p<0.05), DO与异养细菌丰度呈极显著负相关(p<0.01); 异养细菌等微生物的代谢转化活动和陆源输入共同决定DOM的来源和转化, 但异养细菌对DOM具体的驱动转化机制有待于进一步的研究。     

Faecal contamination of drinking water sources of Dhaka city during the 2004 flood in Bangladesh and use of disinfectants for water treatment

AIMS: To describe the extent of faecal pollution and point of use water treatment strategy during and after the 2004 flood in Dhaka. METHODS: A total of 300 water samples were collected from 20 different drinking water sources in Kamalapur, Dhaka city from August 2004 to January 2005. The level of faecal contamination was estimated using measurements of faecal indicator bacteria (total coliforms, faecal coliforms and faecal streptococci) and isolation of Vibrio cholerae was carried out following standard procedures. Total dissolved solids, dissolved oxygen, hardness, chloride and pH were also monitored. The efficacy of four disinfectants including Halotab, Zeoline-200, alum potash and bleaching powder were tested as point of use water treatment agents. The unacceptable level of contamination of total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS) ranged from 23.8% to 95.2%, 28.6% to 95.2% and 33.3% to 90.0%, respectively. The isolation rates of V. cholerae O1 and O139 were both 0.33%, and non-O1/non-O139 was 7.0%. CONCLUSION: Water collected during and after floods was contaminated with TC, FC, FS and V. cholerae. Although alum potash, bleaching powder, Halotab and Zeoline-200 were all effective general disinfectants, Halotab and Zeoline-200 were superior to bleaching powder and alum potash against FC. SIGNIFICANCE AND IMPACT OF THE STUDY: During and after floods, point of use water treatment could reduce waterborne diseases among flood-affected people.     

三湖连江水库水化学特征

总结了1987年4月至1989年10月三湖连江水库水化学特征,季节变化及其年际变动,结果表明:该水库水质清澈,透明度平均为313cm,pH值平均为7.8,水呈中性,溶解氧丰富平均为8.81mg/L;矿化度平均为121.82mg/L,水型属重碳酸盐类,钙组Ⅱ型水(CⅡCa);水中主要营养元素氮含量高,总氮平均为1.38mg/L,磷含量低,总磷平均为0.022mg/L,氮和磷比为62.7:1,表明磷是水体生物生产力的主要限制性营养元素。多数理化组分周年中出现明显的季节变化,和在平面分布上差异显着,多数理化组分年际变化不明显。       

Epilithic Diatoms as Indicators of Water Quality in the Gravataí River, Rio Grande do Sul, Brazil

The potential use of epilithic diatoms as indicators of organic pollution was evaluated in Gravataí River, RS, (latitude 29°45′–30°12′ S; longitude 50°27′–51°12′ W). The river suffers agricultural impacts in its upper course and urban and industrial organic pollution in its lower course. Epilithic diatoms were sampled eight times from September 2000 to August 2002, at six sites. Species were identified and densities and relative abundances of populations were determined. Simultaneously, physical, chemical and microbiological variables were measured (water temperature, conductivity, turbidity, pH, dissolved oxygen, biochemical oxygen demand (BOD₅), chemical oxygen demand, ammonium, organic nitrogen, total nitrogen, ortho-phosphate, total phosphate, chloride and faecal coliforms). In order to interpret the environmental and biological variables, discriminant analysis and the TWINSPAN methods (Two-Way Indicator Species Analysis) were applied. The results indicated that the concentrations of ortho-phosphate, ammonium, total organic nitrogen, BOD₅ and faecal coliforms characterized a pollution gradient along the river, where changes in the abundance or species composition were observed. Species were classified into three groups: Group A, including species more tolerant to heavy organic pollution and eutrophication, represented by Luticola goeppertiana, L. mutica, Eolimna subminuscula, Nitzschia palea and Sellaphora pupula; Group B, comprised of tolerant and widely distributed species such as Eunotia bilunaris, Frustulia crassinervia, F. saxonica, Navicula cryptocephala, N. cryptotenella, Nitzschia palea var. tenuirostris, Surirella angusta, Pinnularia microstauron and Ulnaria ulna and Group C, with less pollution tolerant species represented by Eunotia sp. and Gomphonema parvulum.     

Fish-habitat relationship in a tropical river under anthropogenic influences

This study analyzes the interaction of fish assemblages with 14 physicochemical and hydrogeomorphological variables at 31 sampling stations along the watershed of the Meia Ponte River, Upper Paraná Basin, Central Brazil, during low and high water seasons in 2001. This river and its tributaries drain both urban and agricultural areas. Fish were caught with sieves along a 100 m stretch demarcated in every sampling site, where environmental variables were also measured. A total of 3508 individuals belonging to 31 species were collected. Fish abundance and environmental data matrices were submitted to a multivariate analysis of co-inertia. Two axes were retained for interpretation (total variance explained = 63.65%) indicating that pH, water temperature, conductivity, chemical dissolved oxygen, and turbidity, all have an influence on fish assemblage structure. The co-structure found (fish assemblages and physicochemical variables) is correlated in both of the axes considered (r = 0.73 and r = 0.68, respectively), and is statistically significant (Monte Carlo test, P < 0.001). This co-structure is regulated by seasonality, but is influenced by fish habitat preferences, spawning and available food, the extent and effects of anthropogenic activities (domestic sewage, agriculture, ranching, urban areas) and the position of sampling stations along the watershed. Handling editor: S. M. Thomaz     

Solar photo-oxidative disinfection of drinking water: preliminary field observations

The feasibility of using solar photo-oxidation to inactivate faecal bacterial contaminants in drinking water has been evaluated under field conditions in India and South Africa. Freshly drawn samples from all six test water sources were low in dissolved oxygen, at 13-40% of the air saturation value. However, vigorous mixing followed by exposure to full-strength sunlight in transparent plastic containers (1-25 l capacity) caused a rapid decrease in the counts of faecal indicator bacteria, giving complete inactivation within 3-6 h, with no evidence of reactivation. These results demonstrate that solar photo-oxidation may provide a practical, low-cost approach to the improvement of drinking water quality in developing countries with consistently sunny climates.     

Water quality dynamics in the Boro-Thamalakane-Boteti river system,northern Botswana

The quality of water in aquatic systems is subject to temporal and spatial variations due to varying effects of natural and anthropogenic factors. This study assessed the dynamics of water quality in the Boro-Thamalakane-Boteti river system along an upstream–downstream gradient above and below Maun during February, May, September and December 2012. Temperature, conductivity, pH, dissolved oxygen, turbidity, Escherichia coli and faecal streptococci were monitored in the settlements of Boro, Maun, Xobe, Samedupi, Chanoga and Motopi along the river system. Comparisons of water quality among settlements using ANOVA and Tukey's honest significant difference test highlighted a significant decline in water quality from upstream to downstream, indicated by increases in microbial numbers and turbidity. The quality of water improved as the water level rose during the peak flooding season in September and declined thereafter. This study highlights the possible influence of human settlements and associated developments on waterbodies, and lends strong support to management efforts to maintain river water quality to ensure the suitability of the water for various ecosystem uses.     

The effect of a sewage treatment plant effluent on the faecal coliforms and enterococci populations of the reception river waters

AIMS: A rural sewage treatment plant and the effect of its effluent on the enterococci and faecal coliforms populations of the receiving river waters was evaluated. METHODS AND RESULTS: The enumeration of bacteria was performed by membrane filtration. Diversity and population similarity were analysed using the PhP-plates system. The treatment plant reduces the number of enterococci and faecal coliforms to values similar to those observed upstream. All water samples showed a high diversity for both bacterial populations. A high similarity in the composition and structure, was detected among all the samples. CONCLUSIONS: The impact of the disposal of treated sewage on the river did not modify the composition of either bacterial populations in the river water. SIGNIFICANCE AND IMAPCT OF THE STUDY: The biochemical phenotyping of bacterial populations is a reliable tool for ecological and biodiversity studies. The obtained results provide a better understanding of the sewage treatment process and the impact of the treated sewage effluents in the environment.