Drinking Water Quality Guidelines Research Articles

Seven-layer and Two-layer Domestic Filters for the Removal of Nephrotoxic Constituents in CKDu prevalent Areas, Sri Lanka: Are these Viable Options?

Consumption of water with nephrotoxic constituents is said to have caused the chronic kidney disease of unknown etiology (CKDu) in Sri Lanka; hence removal of such constituents from potable water has received profound attention. Although seven-layer and two-layer filters have been introduced to the communities in the CKDu prevalent areas, the efficacy of such filters for removal of nephrotoxic constituents has not been adequately evaluated. This study investigates the efficacy of these two filters for improving drinking water quality in the presence of hardness, fluoride, aluminum, and cadmium. Feed water was synthesized with 353, 143 mgL -1 hardness, 1.7, 0.9 mgL -1 fluoride, 1.2, 1.3 mgL -1 aluminum and 1.1, 1.0 mgL -1 cadmium for seven-layer filter and 342, 149 mgL -1 hardness, 1.7, 0.8 mgL -1 fluoride, 1.5, 1 mgL -1 aluminum and 1.1, 1.2 mgL -1 cadmium for two-layer filter simulating wet (October, November) and extremely wet (December) seasons, respectively. Filtered water with the seven-layer filter contained 336, 146 mgL -1 hardness, 1.8, 1.0 mgL -1 fluoride, 0.7, 0.9 mgL -1 aluminum, and 0.9, 0.99 mgL -1 cadmium after 60- and 30-days of operation under wet and extreme wet seasons, respectively. Filtered water with the two-layer filter showed 332, 149 mgL -1 hardness, 0.6, 1.4 mgL -1 fluoride, 0.7, 0.3 mgL -1 aluminum, and 0.5, 0.2 mgL -1 cadmium after 60- and 30- day operation under wet and extreme wet seasons, respectively. The quality of the filtered water from both filters did not comply with the Sri Lanka Standards (SLS) drinking water quality guidelines. The XRD, FT-IR, ESEM-EDX analyses revealed the presence of calcium, magnesium, fluoride, and aluminum in various layers of filter media of both filters. Such constituents retained in the filter media leached out during filtration resulting in higher levels in the permeate. Hence, the use of seven-layer and two-layer filters does not seem to be a promising solution to remove nephrotoxic constituents present in water in CKDu prevalent areas.

Quality survey and spatiotemporal variations of atrazine and desethylatrazine in drinking water in Quebec, Canada

The herbicide atrazine remains in use in Canada, the United States, and several other countries, while being banned since 2003 in the European Union. A comprehensive quality survey of atrazine (ATZ) and one of its metabolites, desethylatrazine (DEA), was conducted in 2015–2018 in drinking water available to consumers in Quebec, Canada. Temporal variations of ATZ and DEA were monitored in tap water from the Montreal area for 18 consecutive months (Temporal survey 2015–2016). Within this time window, the sum of ATZ and DEA in tap water samples (n = 450) varied from 40 to 250 ng L−1 (median: 98 ng L−1). ATZ was systematically detected (100%), with a concentration range of 30–195 ng L−1 (median: 49 ng L−1) while DEA was in the range of 10–187 ng L−1 (median: 36 ng L−1). Maximum ATZ concentrations remained about 25× lower than the Canadian drinking water quality guideline (5000 ng L−1), but 48% of the samples were above that of the European Union (100 ng L−1) regarding the sum of ATZ and DEA. Trends of ATZ and DEA in drinking water were also examined across southwestern Quebec (Spatial survey 2017–2018). The sum of the two triazines in this second set of samples varied from below the method detection limit (for 33 out of the 52 surveyed municipalities) to 104 ng L−1. Apart from Montreal, locations in the southern shore of the St. Lawrence showed generally higher levels of atrazine and DEA. The highest concentrations clustered in the Montérégie region, along the St. Lawrence River (e.g., Brossard, Longueuil, Saint-Constant) and/or downstream from agricultural areas. The ATZ concentrations are suggested to have decreased compared to previous surveys, which is consistent with the decrease in the sales of active ingredients in Ontario (upstream sources) and Quebec.

Capacity building and training approaches for water safety plans: A comprehensive literature review.

The World Health Organization has recommended Water Safety Plans (WSPs), a holistic risk assessment and risk management approach, for drinking-water suppliers across low-, middle- and high-income countries, since publishing its 2004 Guidelines for Drinking-Water Quality. While rapid WSP adoption has occurred, capacity is still catching up to implementation needs. Many countries and regions lack case examples, legal requirements, and training resources for WSPs, corresponding to widespread capacity shortfall in the water supply sector. We undertook a comprehensive review of the literature on capacity building and training for WSPs, with the goal of providing recommendations for multiple stakeholder groups at the scales of individual utilities, national governments, and intermediate units of governance. We propose a WSP training taxonomy and discuss it in relation to the stages of learning (introduction, practice, and reinforcement); describe the importance of customizing training to the target group, local language and circumstances; highlight the relevance of auditing for evaluating change over time; and call for robust methods to monitor WSP capacity development.

Safely Managed Hygiene: A Risk-Based Assessment of Handwashing Water Quality.

Sustainable Development Goal (SDG) Indicator 6.2.1 requires household handwashing facilities to have soap and water, but there are no guidelines for handwashing water quality. In contrast, drinking water quality guidelines are defined: water must be "free from contamination" to be defined as "safely managed" (SDG Indicator 6.1.1). We modeled the hypothesized mechanism of infection due to contaminated handwashing water to inform risk-based guidelines for microbial quality of handwashing water. We defined two scenarios that should not occur: (1) if handwashing caused fecal contamination, indicated using Escherichia coli, on a person's hands to increase rather than decrease and (2) if hand-to-mouth contacts following handwashing caused an infection risk greater than an acceptable threshold. We found water containing <1000 E. coli colony-forming units (CFU) per 100 mL removes E. coli from hands with>99.9% probability. However, for the annual probability of infection to be <1:1000, handwashing water must contain <2 × 10-6 focus-forming units of rotavirus, <1 × 10-4 CFU of Vibrio cholerae, and <9 × 10-6 Cryptosporidium oocysts per 100 mL. Our model suggests that handwashing with nonpotable water will generally reduce fecal contamination on hands but may be unable to lower the annual probability of infection risks from hand-to-mouth contacts below 1:1000.

Chemical variability of groundwater samples collected from Needamangalam Region, Thiruvarur District, Tamil Nadu (India)

The aim of present study was to assess the quality of groundwater from Needamangalam region in Thiruvarur district. Eight different locations were selected to analyze the physicochemical parameters and compared with BIS drinking water quality guideline. From overall analysis, the collected groundwater samples of Needamangalam region are contaminated. These region groundwater samples not suitable for drinking purpose, because the water samples contain high concentration of hardness, alkalinity and total dissolved solids; if use the groundwater of Needamangalam region, shall be cause kidney problems due to excess of calcium hardness. Hence we need special treatment for improve the water quality.

Analysis of Bacteriological Quality of Domestic Water Sources in Kabale Municipality, Western Uganda

In the present study, we assessed the bacteriological quality of water of drinking water sources in Kabale Municipality. A total of 28 water samples were collected from 14 water springs during the dry and wet season and analyzed for determination of Escherichia coli (E. coli), and Total Heterotrophic Bacteria (THB) using the membrane filtration method. Most water springs located in less than 20 meters away from residential areas were associated with bacterial contamination. The mean concentrations of E. coli, total coliforms, and THB were 24.07 CFU/100 ml, 85.71 CFU/100 ml, and 197.07 CFU/100 ml, respectively in the wet season. While in the dry season, the mean concentrations were 2 CFU/100 ml, 10 CFU/100 ml, and 91 CFU/100 ml for E. coli, total coliforms, and THB, respectively. There were significant differences between CFU of total coliforms, HTB, between wet and dry seasons (p = 0.026). Samples collected and analyzed during the wet season for total coliforms did not conform to WHO drinking water quality guideline value of no detection per 100 ml. The study concludes that the majority of spring water sources are located in less than 20 meters away from residential areas with significant paved areas, the presence of septic tanks and pit latrines. Wet season significantly affects the quality of domestic water sources than the dry season. The study recommends that spring water should be treated before drinking due to high bacteria concentrations which makes it unsafe for consumption.

Hydrochemistry and groundwater quality in a semiarid calcareous area: an evaluation of major ion chemistry using a stoichiometric approach.

This study is a wide-ranging evaluation of groundwater within the calcareous semiarid area, Gaziantep in southeast Anatolia, Turkey. The resulting water chemistry data (1) explains the interactions between rock and water, (2) evaluates the quantitative relationships between chemical species (major ions), (3) separates hydrochemical facies, (4) provides information on current water quality for multiple uses, and (5) acts as a benchmark for future research. Relationships between ion concentrations (as meq/L) were analyzed through linear modeling and calculation of coefficients of determination (R2). Stoichiometric calculations were employed to determine the quantitative relationships between ions in groundwater. Calculations between (Ca2++Mg2+) and HCO3- indicated that, even at different concentrations of the total alkaline earth metal ion (M2+), the relative percent remained at 72% for all samples. The majority of Ca2+, Mg2+, and HCO3- ions in groundwater were derived from weathering of calcite, the most common mineral in the local geology. Weathering of dolomite was also important to the contribution of ions in some areas. Ca-HCO3 was found to be the dominant water type for 81% of raw samples; a mixed water type was found in 17% of the samples. The major dissolved components of groundwater are, therefore, Ca(HCO3)2 and, to a lesser degree, Mg(HCO3)2.The sampled groundwater was generally found to meet drinking water quality guidelines for most of the physicochemical quality properties for which standards are available, and with regard to concentrations of Mg2+, Na+, K+, Cl-, SO42-, NO2-, and NH4+. However, NO3-, Ca2+, and HCO3- concentrations in several groundwater samples were in excess of maximum acceptable concentrations (MACs).

Rainwater Harvesting System for Water Supply in a Rural Community in Edo State, Nigeria

Water scarcity is still a major problem in many rural communities in Nigeria. In this study, a rain water harvesting system was designed for Ogbekpen, a rural community in Edo state, Nigeria. A conceptual model for rainwater harvesting was developed using the storm water management model (SWMM), Arcmap 10.1 software and daily rainfall data (2000-2016) obtained from the Nigerian Meteorological Agency (NIMET). Runoff, rainfall intensity and change in elevation of three designated catchment zones were taken into consideration. The results revealed that the total amount of rainwater that could be harvested annually (water supply) was 14,314,351.70 L (14,314 m3) from an overall effective rooftop area of 6025.9 m2. This was three times the annual water demand (4,317,965.60 L (4318 m3)), thus demonstrating the capability of the system to meet annual water demand. The required tank capacities for zones 1, 2 and 3 were 870,412.76 L (870 m3), 955,319.4 5L (955 m3) and 788,629.88 L (789 m3) respectively. Comparative physicochemical and microbial analysis of water from rooftops in the three zones and an existing storage well showed that the latter did not comply with drinking water quality guidelines, thus highlighting the importance of a proper conveyance and storage system to improve water quality and availability in the area.

Arsenic, iron and chloride in drinking water at primary school, Satkhira, Bangladesh

Safe water is essential for all living things. Globally, a good fraction of school-aged children, especially in the developing countries children are suffering from several water-borne diseases. In this study, potable water supplies for primary school children were examined at Satkhira district, Bangladesh to ensure arsenic-free drinking water. In 240 randomly selected tube wells water of the primary schools were monitored from the seven Upazilas in Satkhira district, Bangladesh. The metal content, especially arsenic and iron in the tube wells water were analyzed by atomic absorption spectroscopy. Results indicate that arsenic content was exceeded the World Health Organization (WHO) guideline value maximum contaminated level (10 μg/L) in 49% of the tube wells water and reached up to 167.9 μg/L. The level of iron and chloride content was in the tube wells water from 10.01 to 13479.6 μg/L and 29.3–9987.01 mg/L, respectively. The 49% tube wells (118 out of 240) chloride and 45% tube wells (110 out of 240) iron content were exceeded by the Drinking Water Quality Standards of Bangladesh. The drinking water parameters especially arsenic at Satkhira district did not meet the requirement of the WHO drinking water quality guideline or the Drinking Water Quality Standards of Bangladesh. The obtained data were treated for estimating chronic daily intake (CDI) and Hazard Quotient (HQ). The HQ values were >1 for arsenic in the tube wells water of seven Upazilas at Satkhira district. Lifetime drinking of arsenic-contaminated water may trigger cancer risk to the human health.

Effect on reclamation on mercury concentration in groundwater: a case study of Lubo\u0144 Chemical Plant (Pozna\u0144, Poland)

Luboń Chemical Plant (Poland), founded in 1914, is the place where many products such as superphosphate, hydrofluoric acid, sulfuric acid, aluminum fluoride, potassium fluoroborate, vanadium catalyst and other chemicals and post-production waste have been produced and stored. The main products manufactured by Luboń Chemical Plant are powdered superphosphate (obtained from apatite) and sulfuric acid (obtained from pyrite) The aim of the study was to determine the impact of the former post-crystallization leachate disposal site located in the area of Luboń Chemical Plant on groundwater contamination with mercury. Groundwater samples were collected from 12 piezometers in the area of the plant or in close vicinity to the plant, and from one piezometer located 2.5 km north of the study area, i.e., from Poznań-Dębina groundwater intake, in the years 2007–2014. Total mercury concentration in groundwater from Luboń was high in all samples, and ranged from 10.9 to 2818 ng L− 1 (average 335 ± 509 ng L− 1, median = 158 ng L− 1). The highest mercury concentration values were measured in piezometer no. 7, located in close proximity to the production facilities of the chemical plant, and they equaled 2604 ng L− 1 in 2007 and 2818 ng L− 1 in 2008. The lowest concentration of mercury (10.9 ng L− 1) was determined in 2014, in a sample taken from piezometer no. 13 located at the water intake for the agglomeration of Poznań (Poznań-Dębina). Based on the obtained results, two sources of groundwater pollution were found: (1) Luboń Chemical Plant, and (2) former post-crystallization leachate disposal site. A decrease in mercury concentrations with increasing distance of piezometers from the pollution sources was reported. Moreover, a reduction in mercury concentration over the years has been observed, especially after completion of reclamation and remediation works in the area of Luboń Chemical Plant in 2008. Despite the negative impact of the plant on groundwater quality measured in the piezometer located at the water intake Poznań-Dębina, the drinking water quality guidelines (1000 ng L− 1) was not exceeded.

Assessment of water quality and trace metal contaminations in Mondolkiri province in the Northeastern part of Cambodia

The aim of the present study is to investigate water quality and potential trace metal contaminations in the Northeastern part of Cambodia. Tube well (n = 35), hand-dug well (n = 18), channel (n = 10) and lake/pond (n = 8) water samples were randomly collected from Mondolkiri province which is located in the Northeastern highland of Cambodia. A water sample was collected in two different bottles. One was filled in 30-mL polyethylene bottle after which was acidified to pH < 2 with concentrated HNO3. Another was filled in 250-mL polyethylene bottle. The collected water sampled was stored in a cooler during fieldwork and transferred to a fridge where they are stored at 4°C for analysis. The measurement of pH, ORP, dissolved oxygen (DO), turbidity, conductivity, total dissolved solids (TDS) and salinity was taken at laboratory following standard procedures. All chemical measurement of trace metals were taken by inductively coupled plasma mass spectrometry (ICP-MS). Analytical results reveal that tube well (47.1%), hand-dug well (77.8%) and channel water (20%) have pH < 6.5. Turbidity of tube well (32.4%), hand-dug well (5.6%), lake water (12.5%) and all channel water samples are exceeded Cambodia regulation of 5 NTU. Mean As, Cd, Cr, Cu, Ni, Pb and Zn concentrations in Mondolkiri's water sources are below Cambodian drinking water quality standard and WHO's drinking water quality guideline. However, the upper range of Pb in tube well and channel water and Zn in tube well are exceeding Cambodia regulation. Concurrently, the mean concentrations of Fe and Mn in tube well and channel water are exceeded Cambodian aesthetic guideline of 300µgL-1 and 100µgL-1, respectively. This study suggests that appropriate treatment technologies are necessary for residents in the Mondolkiri province to access to clean water and minimize their potential health risks.

Public health risk assessment from drinking water from vending machines in Seri Kembangan (Malaysia)

This study investigated the public health risk linked with microbial quality of drinking water from vending machines in Seri Kembangan city (Malaysia) using epidemiological and Quantitative Microbial Risk Assessment (QMRA) approaches. This study was also conducted to understand associations between reported health symptoms and daily water intake information. Following WHO guidelines on water safety, QMRA were performed was to estimate burden of disease from E. coli from water vending machines. Triplicate drinking water samples from water vending machines were collected from six sampling areas around the city, analysed for E. coli, information of health symptoms and daily water intake was obtained from 121 respondents by questionnaires. The results indicated the highest numbers of E. coli levels were found in Seri Serdang (45–68 CFU/100 mL) and Taman Pinggiran Putra (45–62 CFU/100 mL). Escherichia coli levels in drinking water samples from water vending machines obtained from Seri Serdang, Taman Pinggiran Putra, Taman Equine, Balakong and Serdang Jaya exceeded both Malaysian Drinking Water Quality and WHO Drinking Water Quality guidelines. Reported health symptoms were only significantly linked to brand which likely to be associated with regular maintenance of water vending machine. All the drinking water samples from water vending machines except from Lestari Perdana have exceeded the health based target outcomes by QMRA. Combination of epidemiology and quantitative microbial risk assessment have provided a clear understanding of public health risks and gateway for a better management of water vending machines.

Synthesis and characterisation of calix[4]arene based bis(triazole)-bis(hexahydroquinoline): Probing highly selective fluorescence quenching towards mercury (Hg2+) analyte

In the present study, we are reporting the synthesis of a triazoles incorporated fluorescent hexahydroquinoline appended calix[4]arene 7 and its highly selective optical recognition ability towards Hg2+. The optical sensor 7 was synthesized via two different synthetic pathways and unambiguously characterized by mass spectrometry and NMR spectroscopy. The stoichiometric ratio between 7 and Hg2+ was determined as 1:1 based on Job’s plot and ESI-MS analysis. The chemosensor 7 selectively recognized Hg2+ in the presence of competitive cations such as Cu2+, Cu1+, Co3+, Ni2+, Ag1+, Fe2+, Fe3+, Cr3+, Pb2+, Cd2+, Zn2+, Sn2+, Ti4+, Sb3+, In3+, Ba2+, Ca2+, and K1+. The limit of detection (LOD) was established as 0.5 μM on spectrofluorimetric analysis. According to world health organization (WHO) in guidelines for drinking-water quality, the mercury level in natural occurring ground and surface water is about ∼0.5 μM (μg/L). The supra molecule 7 with LOD (0.5 μM) could potentially serve effective receptors for Hg2+ cation. The probe 7 was applied effectively for detection of Hg2+ in real water samples (i.e. tap and deionized water), spiked with Hg2+ (10 μM) solution. Moreover, the compound 7 showed non-toxicity during cytotoxic assay against human B cells as they retain their morphology. The supramolecule 7 in living cells showed selectivity towards Hg2+ in cytotoxic assay with T lymphocytes, evident by morphological changes observed via AFM analysis.

Assessment of Open well Water Quality around Puttalam District, Sri Lanka

This study focused upon the determination of physicochemical parameters, in drinking water samples of different areas in Puttalam district, Sri Lanka. The purpose was to evaluate the quality of water from these bases. Twenty well water samples were collected from different areas of Puttalam district and analyzed for physiochemical parameters including BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), Total Hardness, Chloride content, TDS (Total Dissolved Solids) and pH. Some Anions (NO3 − and Cl− ) were analyzed for the collected samples. All twenty samples were analyzed separately and were compared with the water quality standard prescribed by the World Health Organization (WHO). It was found that the mean pH values were generally almost the same for the investigated drinking water samples ranged from 6.20 ± 0.0707-7.26 ± 0.007. The well water samples were shown wide variations in other physicochemical parameters. The data showed variations of the investigated parameters in samples are BOD: 1.28 ± 0.0070-5.08 ± 0.0141 ppm, COD: 2.88± 0.0212-24.96 ± 0.070 ppm, Total hardness: 20 ± 1.41241-800 ± 1.414 ppm, Chloride content: 35.45 ± 0.9404-602.65 ± 0.169 ppm, nitrate, 0.0010 ± 0.03-78.4965 ± 0.67 ppm, TDS: 100 ± 2.8284-2000 ± 2.828 mg/L. The concentrations of most of the investigated parameters in the selected drinking water samples from different areas in Puttalam district were not within the permissible limits of the World Health Organization drinking water quality guidelines.

Occurrence of Uranium in Groundwater Along the Lithological Contacts in Central Tamilnadu, India: An Isotope Hydrogeochemical Perspective

Groundwater contributes to the highest exposure level of naturally occurring uranium (U) to biosphere, and hence, the source and concentration of uranium in groundwater needs to be monitored periodically. In the present study, groundwaters from different lithologic locations were collected and measured for uranium concentration and major ions in order to establish any possible link with the lithology on the uranium distribution in central parts of Tamil Nadu, South India. About 11% of the samples contain U in excess of the permissible limit of WHO (Guidelines for drinking-water quality, WHO, Geneva, 2011), and the contamination was limited to mostly hard rock terrain, which is granitic in nature. The correlations among U, major ions, and environmental isotopes were studied to understand the mechanism governing uranium dissolution and transport in groundwater of this region. Observations lead us to infer that the older water with near-neutral pH and oxidizing condition contains higher dissolved U compared with relatively young groundwater. The results also reflect the possible health risk to the local population through long-term consumption of uranium-containing groundwater without any pretreatment.

Investigating water quality and arsenic contamination in drinking water resources in the Tavşanlı District (Kütahya, Western Turkey)

Arsenic is a natural component of the earth’s crust, and it is transported into surface water and groundwater through the dissolution of rocks, minerals and ores. In addition, arsenic leaching processes contaminate water sources and this geogenic arsenic contamination causes significant water quality problems in many parts of the world. In this study, water quality, arsenic contamination and human health risks of drinking water resources in the Tavsanli District were determined and the origins were discussed. For this purpose, geological and hydrogeological properties were investigated. In situ measurements and chemical analyses were carried out on water samples taken from drinking water sources such as wells, springs and surface waters for hydrogeochemical studies. According to the obtained results, water resources are Ca–Mg–HCO3, Mg–HCO3 and Na–HCO3 type. Total As (AsT) concentration of the water samples sometimes exceeds the permissible limit given by the TSI-266 (Standards for drinking waters, Turkish Standards Institution, Ankara, 2005) and WHO (Guidelines for drinking-water quality, World Health Organization, Geneva, 2008) for drinking water. H3AsO 3 0 and HAsO4 2− are dominant arsenic species in groundwater and surface water, respectively. Typically high total arsenic concentrations can be found in regions characterized by magmatic rocks. In addition, As concentrations in surface waters were found to be higher than in groundwater in the region, due to the anthropogenic influence of mining activities in the region.

Spatial and Temporal Heavy Metal Distribution and Surface Water Characterization of Kanjli Wetland (a Ramsar site), India Using Different Indices.

Suitability of surface water of Kanjli wetland, Punjab (India) during the period of 2013-2015 was assessed for drinking, irrigation and aquatic life using a water quality index (WQI), heavy metal pollution index (HPI) and aquatic toxicity index (ATI). WQI was calculated using 14 physico-chemical parameters while HPI determination used nine heavy metals like As, Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn. WQI revealed that Kanjli wetland contained medium quality water (irrigation and aquatic life). Cr, Cd and Co exceeded desirable limits of World Health Organization (WHO, Guidelines for drinking-water quality, World Health Organization, Geneva, 2011) and Indian drinking water standard (2012) during all the three seasons (monsoon, post monsoon and winter). HPI values from all sites exceeded critical pollution index value of 100 during monsoon season. Few sites were unsuitable for normal fish life as per ATI. The study recommends planned spatial, temporal and periodic monitoring of wetland using WQI and HPI to sustain good water quality (drinking, irrigation and aquatic life).

The impact of various land uses on the microbial and physicochemical quality of surface water bodies in developing countries: Prioritisation of water resources management areas

To protect water resources, the WHO recommends assessing land use influence on water quality, taking into consideration residential development and waste disposal amongst others. Thus, we investigated the impact of unconstructed plots, an informal settlement, an urban residential area, and an industrial area on the microbiological and physicochemical quality of two main tributaries within the Klein Jukskei catchment, Johannesburg, South Africa, to identify areas where immediate resource management strategies were needed. Water samples collected from the tributaries’ sources and upstream and downstream from each land use type (Winter and Spring) were analysed for E. coli (indicator organism), using the Colilert® 18 system. Physicochemical parameters (Temperature, pH, dissolved oxygen, electrical conductivity, turbidity and total dissolved solids) were measured using multiparameter instruments. The tributaries’ sources had the lowest E. coli counts (Sandspruit – 0.74; North Ridingspruit – 1.18log10 MPN/100mL) during the study. After flowing through the various land uses, mean E. coli counts reached 5.98 (Sandspruit) and 4.85log10 MPN/100mL (North Ridingspruit). E. coli values and all physicochemical parameters (but for pH) downstream from most of the land uses did not meet the South African drinking water quality guidelines. The informal settlement had the most negative impact on the microbial and physicochemical quality of the water within the tributaries. Thus, providing informal settlements with appropriate sanitation facilities is likely to prevent pollution of the water bodies. Protection of the sources should also be implemented while industrial wastes need to be monitored for conformity with water quality guidelines before discharge.

Assessment of drinking water quality and its health impact on local community in coastal belt Karachi

For survival of human beings clean water is an essential commodity whereas contamination in drinking water threatens to mankind. The main cause of water contamination is social and development activities of human being along with increasing population. The community in the study area has acute shortage of drinking water along with about 40 to 60% has no access to safe drinking water. This study indicates drinking water quality of two major sources of coastal belt of Karachi one is supplied by Karachi Water & Sewerage Board (KWSB) as tap water and the other through groundwater. The physicochemical analysis was carried out by following the standard methods for checking the quality of drinking water. The analyzed results showed that the quality of groundwater was unfit as potable water. The most critical situation was observed as high level of contamination followed by high turbidity and increased salinity levels. TDS in surface water were found 12% above and TDS in groundwater was 20% below the National Drinking Water Quality Standards (NDWQS) of Pakistan as well as the permissible WHO drinking water quality guidelines.

Microbiological contamination of water pans in Baringo County

Water pans constitute the main source of rural water supply in Baringo County. This study sought to assess the spatial-temporal variation of total coliforms, Escherichia coli, Fecal streptococcus and Salmonella species in the water pans. A sanitary survey was conducted to observe the potential sources of microbial contamination on the water pans. Water was sampled from one protected and five unprotected water pans (n = 6) in the study area for a period of 4 months (June–October 2015). A total of 72 water samples were sampled in triplicate from the water pans for microbial analyses, membrane filtration technique was used in assaying for microbial counts of total coliforms, E. coli, F. streptococcus and Salmonella species in water samples. The results show that there was a significant spatial variation in F. streptococcus amongst the protected and the unprotected water pan sampled sites (p = 0.008), and there was a statistically temporal significant difference (p = 0.001) for total coliforms and Salmonella species during the dry seasons, respectively. Given the prevalence of the selected diseases causing pathogens in water above the WHO drinking water quality guidelines, households are advised to treat the water before use.