Assessment of spring water quality and quantity, and health implications in Tongaren division, Nzoia River catchment, Kenya

Spring water is the common source of public water supply in most rural communities of developing countries such as Kenya. The water quality and quantity may be altered due to catchments degradation. This study was carried out in Tongaren division, Nzoia River catchment. The aim of this study was to investigate and map the occurrence and distribution of springs and to determine their water quality and quantity. This study determined the spring water discharge, conductivity, turbidity, total and thermotolerant (faecal) coliforms to assess suitability and sustainability of spring water for safe drinking. Twenty-eight springs were identified and their locations mapped using Global Positioning System (GPS) geo-reference data. Discharge ranged from 0.1 to 3 l s⁻¹, with some drying up during dry season. Total coliform was innumerable in most of the studied springs while thermotolerant (faecal) coliform counts occurred in eight springs, including four protected springs. This poses high risks of water-borne diseases. The water should be filtered and boiled prior to use for drinking. Facilitation of communities enabled development of seven springs to enhance water yield and quality. This study established high potential in the communities to develop springs and utilize the spring water as alternative source of livelihoods.     

Evaluation of coliforms as indicators of water quality in India.

The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed.     

A seasonal survey of gastrointestinal parasites in captive wild impala antelope on a game facility south of Lusaka, Zambia

Faecal samples (n?=?1947) from captive wild impala (Aepyceros melampus melampus) were examined over a period of 14 months to determine quantitative seasonal helminth egg excretion patterns and qualitative protozoan oocyst excretion patterns. Geometric mean monthly faecal egg counts (FECs) ranged from 20 to 575 and coprocultures revealed three parasite genera, namely Trichostrongylus, Haemonchus and Strongyloides. Larvae of the Trichostrongylus spp. were most predominant from faecal cultures. No trematode eggs or lungworms were detected and eggs of the cestode Monezia were only seen in two samples during the entire study period. The nematode FECs showed a marked seasonal variation, being higher during the rainy season, moderate during the cool dry season and low during the hot dry season. The rainy season had significantly higher FECs than the dry season (P?0.05), but were significantly higher in pelleted faeces in the rainy season than the dry season (P?相似文献   

Occurrence and densities of bacteriophages proposed as indicators and bacterial indicators in river waters from Europe and South America

AIMS: To evaluate the feasibility of bacteriophages as a complementary tool for water quality assessment in surface waters from different parts of the globe. METHODS AND RESULTS: Faecal coliform bacteria, enterococci, spores of sulphite-reducing clostridia, somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis were determined by standardized methods in raw sewage and in 392 samples of river water from 22 sampling sites in 10 rivers in Argentina, Colombia, France and Spain, which represent very different climatic and socio-economic conditions. The results showed that the indicators studied maintained the same relative densities in the raw sewage from the different areas. Classifying the river water samples according to the content of faecal coliform bacteria, it can be observed that the relative densities of the different bacterial indicators and bacteriophages changed according to the concentration of faecal coliform bacteria. There was a relative increase in the densities of all groups of bacteriophages and sulphite-reducing clostridia with respect to faecal coliforms and enterococci in the samples with low counts of faecal coliform bacteria. CONCLUSIONS: The numbers of bacterial indicators and bacteriophages were similar in the different geographical areas studied. Once released in rivers, the persistence of the different micro-organisms differed significantly. Bacteriophages and spores of sulphite-reducing clostridia persisted longer than faecal coliforms and enterococci. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriophages in river water samples provide additional information to that provided by bacteria about the fate of faecal micro-organisms in river water. The easy, fast and cheap methods for phage determination are feasible both in industrialized and developing countries.     

Evaluation of coliforms as indicators of water quality in India

P.W. RAMTEKE, J.W. BHATTACHARJEE, S.P. PATHAK AND N. KALRA. 1992. The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed.     

Potential sources of bacteriological pollution for two bays with marinas in Trinidad

Welcome Bay and Chaguaramas Bay in the northwest peninsula of Trinidad contain large marinas and smaller sections of bathing beaches. Bacteriological surveys were conducted at both bays to assess water quality and to determine potential sources of pollution. These surveys were conducted during the wet season of 1996 and the dry season of 1997. Eleven sample stations were established at Welcome Bay and 12 at Chaguaramas Bay. Freshwater samples were collected from rivers and drains within the survey area. Marine water samples were collected from marinas, bathing beaches and inshore and outer areas at both bays. Five water samples were collected from each sampling station during the wet season of 1996 and six during the dry season of 1997. The membrane filter technique was used to determine faecal coliform and Escherichia coli levels in all samples. There was a seasonal effect on water quality, with significantly higher faecal coliform levels in the wet season, when water quality was not in compliance with international standards. This represents a potential health risk in bathing areas. Water quality was better at the outer area of both bays. Water quality at the inner bay areas was most likely adversely affected by land-based sources of pollution identified in this study. These sources include three drains and two rivers, which discharged into the bays. Yachts were apparently not a source of sewage pollution: there was no significant relationship between yacht number and faecal coliform levels.     

Coliform dynamics and the implications for source tracking

In many parts of the world, coliform counts in recreational waters are unacceptably high. In an attempt to rectify this problem, programmes are under way to develop methods that will allow the sources of the faecal contamination thought to be responsible for these elevated counts to be identified. The success of these efforts depends on the validity of several assumptions that underlie many of the proposed methods. One of the critical assumptions is that the clonal composition of the coliform species being monitored in a water body reflects the clonal composition of the species in the host populations responsible for the faecal inputs into that water body. To determine the extent to which among-strain variation in a coliform species might invalidate this assumption, a series of simple mathematical models was proposed and analysed. The first series of models assumed that all cells of species were identical. The question posed was - is the density of a coliform species in a body of water linearly related to the rate at which cells of the species enter the water body via faecal production? The results of these models suggest that, over a wide range of conditions, cell densities in the water body are linearly related to the rate at which cells enter the water body as a result of faecal contamination. This outcome occurs whether or not cells are capable of division in the external environment. When the rate of cell division depends on the concentration of available nutrients then, when nutrient input rates are 'high' and rates of faecal contamination are 'low', this linear relationship does not hold. The second series of models assumed that the coliform species consists of different strains and that these strains differ in their performance in the external environment. The results of these multistrain models show that the relative abundance of strains in the external environment is unlikely to reflect their relative abundance in the faecal inputs to the environment. Consequently, statements such as - domestic animals are responsible for 30% and wildlife for 70% of the faecal inputs to a water body - may well be meaningless.     

Diet and distribution of elephant in the Maputo Elephant Reserve, Mozambique

The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung counts, satellite tracking and faecal analysis. The results were compared with earlier data from before the civil war in Mozambique. The elephant population decreased during the civil war, but 180 animals still remain. Earlier studies described the elephants as preferring the grass plains. Currently, the elephants prefer the dense forest patches over the high quality forage found in the grass plains. Water salinity affected distribution; elephant dung piles were found closer to fresh water in the dry season. A total of 95 different plant species were identified in the faeces. The percentage of grass was relatively low compared with other studies, increasing at the beginning of the rainy season. At the end of the dry season, elephants concentrated on the few available browse species with young leaves, but generally preferred grass species to browse species. Diet composition was mainly affected by season and less by habitat. The elephants have changed their habitat preference in reaction to poaching, and probably increased the contribution of browse species in the diet. The presence of forest patches has been vital for the survival of the elephants.     

Wastewater-grown duckweed may be safely used as fish feed

Duckweed has been used for the treatment of wastewater and as fish feed. A comparative study was carried out to determine (i) the efficacy of duckweed in treating hospital-based wastewater and (ii) the level of the microbial contamination of fish fed on wastewater-grown duckweed. There were two groups of ponds where fish farming was done. In one group of ponds (control ponds), duckweed that was grown using artificial fertilizer was used as fish feed; in another group (study ponds), wastewater-grown duckweed was used as fish feed. The faecal contamination of water, duckweed, and fish from study and control ponds were monitored by faecal coliform estimation. The presence of enteric pathogens among handlers, water, duckweed, and fish samples was also examined. It was observed that the faecal coliform counts of raw wastewater were 4.7 Log10 CFU/mL, which was reduced to <1 Log10 CFU/mL after treating with duckweed. There was no significant difference (P > 0.05) in faecal coliform counts in water collected from duckweed ponds and fish ponds of study and control areas. The wastewater-grown duckweed did not pose any health hazard to the handlers. These results demonstrated that the wastewater-treated duckweed may be safely used as fish feed.     

Inactivation of <Emphasis Type="Italic">Escherichia coli</Emphasis> and coliform bacteria in traditional brass and earthernware water storage vessels

The detection and enumeration of indicator bacteria such as Escherichia coli is used to assess the extent of faecal contamination of drinking water. On the basis of this approach, the effectiveness of storing water contaminated with faecal indicator bacteria in brass or earthern vessels (mutkas) of the type used in rural India have been investigated. Suspensions of bacteria in sterile distilled water were maintained for up to 48 h in each vessel and enumerated by surface plate counts on nutrient agar (non-selective) and several selective coliform media at 37 °C either under standard aerobic conditions, or under conditions designed to neutralise reactive oxygen species (ROS), e.g. using an anaerobic cabinet to prepare plates of pre-reduced growth medium or by inclusion of sodium pyruvate in the growth medium, with incubation of aerobically-prepared plates in an anaerobic jar. The counts obtained for E. coli decreased on short-term storage in a brass mutka; counts for selective media were lower than for equivalent counts for non-selective medium, with ROS-neutralised conditions giving consistently higher counts than aerobic incubation. However, after 48 h, no bacteria were cultivable under any conditions. Similar results were obtained using water from environmental sources in the Panjab, and from rural households where brass and earthern mutkas are used for storage of drinking water, with enumeration on selective coliform media (presumptive total coliforms). In all cases results indicated that, while storage of water in a brass mutka can inactivate E. coli and coliforms over a 48 h period, standard aerobic plate counting using selective media may not be fully effective in enumerating sub-lethally damaged bacteria.     

The role of visible faecal material as a vehicle for generic Escherichia coli,coliform, and other enterobacteria contaminating poultry carcasses during slaughtering

AIMS: A comparison of Enterobacteriaceae, coliform and Escherichia coli counts in chicken carcasses with and without visible faecal contamination was conducted to evaluate the role of contamination as a vehicle for generic E. coli, coliform and other enterobacteria contaminating broiler chicken carcasses when processed under routine commercial operations. METHODS AND RESULTS: Samples were removed from the processing line immediately after evisceration, inside-outside shower and chilling for microbiological analysis. After evisceration, mean counts were significantly different only for E. coli (P < or = 0.05) in chicken carcasses with and without visible faecal contamination. While the spray wash practice was not efficient enough for complete removal of the visible contamination from carcasses, leading to microbiological reduction percentages lower than expected, 25 ppm chlorinated water chilling did reduce the contamination level considerably in all samples. CONCLUSIONS: Carcasses with and without visible faecal contamination harboured E. coli and other potentially hazardous enterobacteria. E. coli was the predominant strain isolated in all samples, Enterobacter cloacae being next most frequent. SIGNIFICANCE AND IMPACT OF THE STUDY: The zero tolerance of visible faecal contamination requirement alone is not sufficient to assure safety and to improve the microbial quality of carcasses.     

Proficiency testing of water microbiology laboratories in The Netherlands

In a 3-year period, four series of simulated water samples containing selected test strains were distributed to more than 50 laboratories in The Netherlands for bacteriological testing. Participating laboratories examined the samples by enrichment or membrane filtration methods, or both, for total coliform organisms, thermotolerant coliform organisms, faecal streptococci and standard plate counts (37 degrees and 22 degrees C) according to Dutch standard methods. The results were quantitatively satisfactory: the distribution of positive and negative results with subsamples conformed to stochastic variation; the standard deviation of membrane or plate counts was usually in the range which may be expected from a Poisson distribution, and there was good correspondence between average counts in participating laboratories and those expected from controls in the organizing laboratory. Problems of a qualitative nature were frequently encountered, however. Among them were a false positive response with a strain of Enterobacter cloacae in the thermotolerant coliform test; a false positive result with Clostridium perfringens in enrichment tests for total or thermotolerant coliform organisms and false positive results with Micrococcus varians in the faecal streptococcus test by membrane filtration. It is concluded that quality assessment should be a consistent activity in water microbiology laboratories. For this purpose, stable and well characterized reference materials are needed.     

Seasonal variation in the water quality and chlorophyll a of semi-intensive shrimp ponds in a subtropical environment

Twelve water quality variables were measured at different intervals (biweekly and twice a week) in two ponds during two consecutive production cycles in a semi-intensive shrimp farm on the Northwest coast of Mexico. The average harvest during dry season (March–July, a 95 days period) was 1822 kg ha^-1, with an average size of 16.0 g; while the harvest in the rainy season (August–January, a 165-day period) was 2125 kg ha^-1, with an average size of 11.9 g. In the rainy season, dissolved oxygen concentration tended to decrease as the feeding rates and shrimp and phytoplankton biomass were increasing until harvest. During both culture cycles, mean values of temperature, salinity and ammonium in ponds were not significantly different from those in inlet water, whereas pH levels in ponds were higher than in incoming water.Nitrogen nutrients, pH and particulate organic matter levels in ponds and inlet water did not exhibit seasonal differences; the better yield and feed conversion obtained during rainy season reflect the fact that temperature and mean chlorophyll a were higher during the rainy than in the dry season; salinity and total suspended solids were lower during the dry than in the rainy season. The mean levels of the water quality variables in the two ponds were not significantly different in both grow out cycles. Therefore, the differences in productivity between ponds cannot be explained by the water quality.     

新垦红壤坡地土壤水分有效性研究

针对南方红壤地区降雨时空分布不均的特点,以未开垦的自然植被为对照,对桂西北环境移民示范区不同季节(早季和雨季)一次性降雨前1d及降雨后4h、2d、4d、6d及8d新垦蔗地(中坡、下坡、谷地）0-20cm,20-40cm、40-60cm3个土层的土壤水分含量进行了测定．结果表明,雨后谷地蔗地的土壤有效水分增量几乎与降雨量相同,而中坡蔗地与未开垦的自然植被土壤有效水分增量仅相当于降雨量于80％．雨季雨后0-60cm土壤层次中土壤有效水分分布均匀,早季主要集中在表层．雨季一次性降雨后各哩理及各土层土壤有效水分饱和度均有显著差异;而早季3个新垦蔗地间无明显差异,3个土层以表层土壤有效水分饱和度最高,亚表层与心土层差异不明显．无论雨季还是旱季,0-60cm土层土壤有效水分的消耗速率都以自然植被处理为最低,由于雨季正是作物生长旺季,其0-60cm土层土壤有效水分的消耗速率比旱季快,按照早季雨后8d土壤有效水分的平均消耗速率,15d内0-60cm土层的有效水分将消耗殆尽。     

Preliminary study of microbiological parameters in eight inland recreational waters

A pilot survey of the counts of total coliform bacteria, thermotolerant coliform bacteria, Escherichia coli and faecal streptococci was carried out at eight inland recreational waters at weekly intervals during July 1991. The aims were to assess the feasibility of determining candidate indicators of recreational water quality and to assess the possible scale of variability of these parameters. The numbers of total coliforms were difficult to determine reliably because of interference from the background bacterial flora. There was a strong correlation between thermotolerant coliforms and E. coli and faecal streptococci. The average counts of the indicator organisms varied between and within the eight recreational waters by up to 10000-fold. The greatest variation was between the eight recreational waters. At any one water, the greatest source of variation was time but there was substantial variation between sample points at one time. Counts in samples collected 1 m apart exhibited greater than random variation. Counts from surface samples tended to be higher than those at 30 cm or 100 cm depth. The proportion of thermotolerant coliforms confirmed to be E. coli varied from water to water between 60% and 96%.     

Proficiency testing of water microbiology laboratories in The Netherlands

In a 3-year period, four series of simulated water samples containing selected test strains were distributed to more than 50 laboratories in The Netherlands for bacteriological testing. Participating laboratories examined the samples by enrichment or membrane filtration methods, or both, for total coliform organisms, thermotol-erant coliform organisms, faecal streptococci and standard plate counts (37˙ and 22˙C) according to Dutch standard methods. The results were quantitatively satisfactory: the distribution of positive and negative results with subsamples conformed to stochastic variation; the standard deviation of membrane or plate counts was usually in the range which may be expected from a Poisson distribution, and there was good correspondence between average counts in participating laboratories and those expected from controls in the organizing laboratory. Problems of a qualitative nature were frequently encountered, however. Among them were a false positive response with a strain of Enterobacter cloacae in the thermotolerant coliform test; a false positive result with Clostridium perfringens in enrichment tests for total or thermotolerant coliform organisms and false positive results with Micrococcus varians in the faecal streptococcus test by membrane filtration. It is concluded that quality assessment should be a consistent activity in water microbiology laboratories. For this purpose, stable and well characterized reference materials are needed.     

Evaluation of a fluorescent antibody technique for the rapid enumeration of Bacteroides fragilis group of organisms in water

The Bacteroides fragilis group has been evaluated as a prospective rapid indicator of faecal contamination of water. Fluorescent antibody (FA) stained B. fragilis group bacteria were enumerated microscopically and compared with faecal coliform or Escherichia coli counts as indicators of faecal contamination. Environmental samples included surface waters (raw drinking water and known contaminated water). Laboratory disinfection experiments with ozone, chlorine and u.v. radiation were also performed. Bacteroides FA counts specifically detected recent human faecal contamination in field samples in 2-3 h. Samples with a high content of particulates or debris limited the sensitivity to about 10 FA counts/ml. Viable counts showed that the sensitivity to all three disinfection agents was essentially the same for Bacteroides and E. coli. Fluorescent antibody counts of Bacteroides, conversely, were not altered by any of the agents. Therefore, the Bacteroides FA method is not recommended for routine monitoring but may be useful for cases where extensive human faecal contamination is suspected (e.g. pipeline rupture or pollution of recreational water) and where rapid remedial action must be taken to protect the public health.     

Soil: the environmental source of Escherichia coli and Enterococci in Guam's streams

We have previously documented that faecal indicator bacteria (Escherichia coli, faecal coliform, enterococci) recommended by the U.S. Environmental Protection Agency (USEPA) to establish recreational water quality standards are naturally found in high concentrations in the surface and subsurface of soils in Hawaii. Rain, the source of all streams in Hawaii, washes the soil sources of faecal bacteria into all the streams of Hawaii, at concentrations which consistently exceed the USEPA recreational water quality standards. The objective of this study was to test the hypothesis that faecal bacteria are able to establish themselves in the soil environments of tropical islands by conducting the same study in Guam, a tropical pacific island with warmer temperatures and higher humidity than Hawaii. The same methods and study design used in Hawaii was used in Guam. The results of the study conducted in Guam revealed that all streams contain consistently high concentrations of faecal coliform, E. coli, and enterocci which exceeded the old USEPA recreational water quality standard of 200 faecal coliform/100 ml as well as the new water quality standards of 126 E. coli/100 ml or 33 enterococci/100 ml. These same faecal indicator bacteria were recovered in high concentrations in surface and subsurface (18-36 cm depth) soil samples in Guam. Limited coastal water analysis showed that most coastal marine waters contain low concentrations of faecal bacteria but coastal waters impacted by stream run-off showed elevated levels of faecal bacteria. The results of this study support the hypothesis that environmental conditions in the tropical areas of the world can support the growth and establishment of populations of faecal bacteria in the soil. Thus, soil becomes an environmental, non-faecal source of faecal indicator bacteria. These results indicate that USEPA water quality standards may not be directly applicable to tropical island environments.     

Preliminary Studies on Membrane Filtration for the Production of Potable Water: A Case of Tshaanda Rural Village in South Africa

Ultrafiltration (UF) systems have been used globally for treating water from resources including rivers, reservoirs, and lakes for the production of potable water in the past decade. UF membranes with a pore size of between 0.1 and 0.01 micrometres provide an effective barrier for bacteria, viruses, suspended particles, and colloids. The use of UF membrane technology in treating groundwater for the supply of potable water in the impoverished and rural village, Tshaanda (i.e., the study area) is demonstrated. The technical and administrative processes that are critical for the successful installation of the pilot plant were developed. Given the rural nature of Tshaanda, the cultural and traditional protocols were observed. Preliminary results of the water quality of untreated water and the permeate are presented. Escherichia coli in the untreated water during the dry season (i.e., June and July) was 2 cfu/100 ml and was <1 cfu/100 ml (undetected) following UF, which complied with the WHO and South African National Standards and Guidelines of <1 cfu/100 ml. During the wet/rainy season (February) total coliform was unacceptably high (>2419.2 cfu/100 ml) before UF. Following UF, it dramatically reduced to acceptable level (7 cfu/100 ml) which is within the WHO recommended level of <10 cfu/100 ml. Additionally, during the wet/rainy season E. coli and enterococci were unacceptably high (40.4 cfu/100 ml and 73.3 cfu/100 ml, respectively) before UF but were completely removed following UF, which are within the WHO and SANS recommended limit. The values for electrical conductivity (EC) and turbidity were constantly within the WHO recommended limits of 300 µS/cm corrected at 25°C and <5 NTU, respectively, before and after UF, during dry season and wet season. This suggests that there is no need for pre-treatment of the water for suspended particles and colloids. Considering these data, it can be concluded that the water is suitable for human consumption, following UF.     

Rainfall and birthweight distribution in rural Tanzania

This paper explores the possibility of using different techniques of time-series analysis lagged regression analysis for the study of the complicated interaction between ecological, socioeconomic and nutritional variables. The data discussed originate from a rural area in Tanzania, where life is subject to a marked seasonal variation, dependent on a bi-modal rainfall pattern. The unreliability of rainfall is characteristic: both drought and excessive rainfall are frequent occurrences. Seasonal variationns in birthweights over a 10-year period (1972-81) are here compared with the local rainfall pattern. Data on birthweight for this period show that birthweight was highest at the end of the dry season, fell rapidly during the 1st 1/2 of the rainy season, rose again during the later part of the rainy season, and fell to its lowest value just after the rans. It is argued that there are good reasons to attribute these variations to changes in labor output, food consumption, and health status, all of which are related to the seasonal cycle. Mean birthweight fell by about 60g. in the course of the rainy season. Lagged regression analysis reveals a negative impact of rainfall on birthweight after 3 months. Deviations from average rainfall show a positive correlation with birthweight after 4 months, but only in the months when rainfall is critical for food crop production. The interactions of these contrary effects are held responsible for the observed sudden fluctuations in mean birthweight.