Drinking Water Quality Guidelines Research Articles

Hepatitis A virus in surface water in South Africa: what are the risks?

The aim of this study was to assess the potential risk of infection constituted by HAV to persons using surface dam and river water for domestic and recreational purposes. It estimates the potential risk using a deterministic exponential risk assessment model with mean values and conservative assumptions. Hepatitis A virus was detected in 17.5% of river and 14.9% of dam water samples tested. The number of indicator organisms in these sources exceeded drinking and recreational water quality guidelines set by the United States Environmental Protection Agency (US EPA), indicating possible health risks to recreational water users. Based on the available data and taking all the assumptions into consideration, the probability of infection (Pinf) to the higher socio-economic population using the river water for recreational purposes was 1.1 x 10(-3) per day and 3.3 x 10(-1) per annum if 100 ml was ingested per day. For recreation in the dam water the Pinf value was 1.2 x 10(-4) per day and 4.2 x 10(-2) per annum. For the lower socio-economic population, risk values for drinking purposes (2 L day(-1)) were ten-fold greater. These surface waters therefore did not conform to the US EPA guidelines of 1 infection per 10,000 consumers per year for drinking water or eight gastrointestinal illnesses per 1,000 bathers per day in environmental waters used for recreational purposes. This is the first risk assessment study addressing the risk of infection by HAV in surface water to different socio-economic populations in South Africa.

Analysis of Acrylamide in Water Using a Coevaporation Preparative Step and Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry

Acrylamide is a probable human carcinogen, and the drinking water quality guideline for this compound is 0.5 mg/L. However, analysis of this compound in water is difficult because of its very high water solubility, which limits the efficiency of sample preconcentration prior to analysis. We developed a robust and sensitive analytical method for the determination of trace quantities of acrylamide in samples of water using a novel preparative technique and isotope dilution liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization as the ion source (LC-APCI-MS/MS). The preparative method involves coevaporation of acrylamide with water at pH 10 using a rotary evaporator, followed by acidification to pH 3.0 and concentration of the sample prior to analysis by LC-APCI-MS/MS. To compensate for the loss of the analyte during sample preparation and signal suppression due to interference from the sample matrix, isotope dilution with acrylamide-d3 was used for quantitation. Using this method, analyte recoveries ranged from 74 to 103% for acrylamide spiked into water at a concentration of 0.4 ng/mL. The limit of detection and limit of quantification (LOQ) for acrylamide in water were 0.02 and 0.06 ng/mL, respectively. This method was successfully applied to determine trace levels of acrylamide in samples of river water and in runoff from an agricultural field to which municipal biosolids (i.e., sludge) had been applied. Concentrations of acrylamide in these samples ranged from <LOQ to 0.16 microg/L.

A mechanistic study on boron rejection by sea water reverse osmosis membranes

Boron is a vital element for organism growth, but excessive exposure can cause detrimental effects to plants, animals, and possibly humans. However, it has been challenging for many of the existing sea water reverse osmosis (SWRO) membrane plants to remove boron and meet the current World Health Organization Guidelines for Drinking Water Quality. The objective of this study was to evaluate the effect of key operating parameters such as pH and temperature on boron rejection and develop a corresponding mechanistic predictive model. Bench-scale cross-flow filtration experiments were performed to estimate the rejection of boron by six commercial SWRO membranes. The rejection of boron appeared to follow a mechanism which is different from those of other ionic solutes and could not be readily correlated with their rejections. An irreversible thermodynamic model coupled with film theory was applied to quantitatively analyze the experimental observations. The model accurately predicted the boron rejection performances of the SWRO membranes at different operating conditions. The model was further modified to account for the boric acid speciation by pH and temperature dependence of the model parameters. The model developed herein will constitute fundamental for performance prediction and design of SWRO processes.

Hydrochemical evidence of the depth of penetration of anthropogenic recharge in sandstone aquifers underlying two mature cities in the UK

Pollution of urban groundwater is routinely reported but the profile of contamination with depth in urban aquifers is rarely resolved. This limits understanding of the depth of penetration of urban recharge and contaminants, and use of urban groundwater. Penetration of anthropogenic solutes (major ions, trace metals) in Permo-Triassic sandstone aquifers underlying two mature conurbations in the UK was investigated through depth-specific, groundwater sampling of dedicated multilevel piezometers. Identification of solute origin and biogeochemical processes (e.g. denitrification, mineral dissolution) was aided by use of stable isotope ratios ( 34S/ 32S, 18O/ 16O, 15N/ 14N, 13C/ 12C) and chemical speciation modelling (PHREEQC). Depth profiles of aquifer hydrochemistry reveal penetration of anthropogenic solutes to depths of between 30 and 47 m below ground in the unconfined sandstone and confirm the contributions of faecal and industrial effluents to urban recharge. They also highlight the complexity of solute loading and difficulty resolving solute origin from the range of potential sources in urban groundwater. Faecally-derived NO 3 is the most pervasive contaminant exceeding drinking-water quality guidelines and is associated with elevated concentrations of B and SO 4. Elevated concentrations of Li, B, Cr and Co are observed at depth in groundwater contaminated by long-term industrial land use (metalworking). Observed penetration of anthropogenic solutes in the unconfined sandstone is consistent with post-development recharge of urban groundwater (residence times <230 a) indicated by flow modelling, and suggests tentatively that urban abstraction to depths of up to 50 m below ground in the unconfined Permo-Triassic sandstone is required to scavenge contaminated groundwater.

Comparative study of Drinking Water Quality Parameters of three Manmade Reservoirs i.e. Kolar, Kaliasote and Kerwa Dam

A physico-chemical study of the Kerwa dam, Kolar dam and Kaliasote dam of Bhopal has been carried out to examine the suitability of surface water for drinking purposes. Water Samples were collected from two sampling stations of each dam and analyzed (APHA, AWWA, WEF, 1998) for the physico–chemical parameters such as temperature, pH, electrical conductivity, total hardness, calcium hardness, magnesium hardness, sulphate, fluoride and chemical oxygen demand (COD) to know the present status of the water bodies. The concentrations of investigated parameters in the water samples were within the permissible limits of the World Health Organization drinking water quality guidelines except for the values of COD and total hardness. The value of COD was found in the range of 18 mg/ l to 30 mg/l which was much higher than the maximum permissible limits as prescribed by WHO standards (1993). The value of total hardness ranges from 118 mg/l to 170 mg/l which is also above the permissible limit as prescribed by WHO standards.

Quantitative microbial risk assessment to estimate health risks attributable to water supply: Can the technique be applied in developing countries with limited data?

In the 3rd edition of its Guidelines for Drinking-Water Quality (2004) (GDWQ) the World Health Organization (WHO) promotes the use of risk assessment coupled with risk management for the control of water safety in drinking water supplies. Quantitative microbial risk assessment (QMRA) provides a tool for estimating the disease-burden from pathogenic microorganisms in water using information about the distribution and occurrence of the pathogen or an appropriate surrogate. This information may then be used to inform decisions about appropriate management of the water supply system. Although QMRA has been used to estimate disease burden from water supplies in developed countries, the method has not been evaluated in developing countries where relevant data may be scarce. In this paper, we describe a simplified risk assessment procedure to calculate the disease burden from three reference pathogens--pathogenic Escherichia coli, Cryptosporidium parvum and rotavirus--in water supplies in Kampala, Uganda. The study shows how QMRA can be used in countries with limited data, and that the outcome can provide valuable information for the management of water supplies.

Quality of “Sachet” Waters in the Cape Coast Municipality of Ghana

To determine the quality of sachet water samples in the Cape Coast municipality of Ghana, random sampling procedures were used to collect 180 samples from 29 brands produced in the municipality from 1999 to 2004. For any particular year, each tested brand was sampled three times at intervals of not less than 2 weeks (usually monthly) between the months of March to June. Forty-five percent (45%) of the brands subjected to bacteriological examination contained coliform bacteria for one sampling period or another during the period of investigation. The coliform contamination seemed to be more prevalent with some particular brands. Three out of seven brands examined in 2004 also recorded the presence of E. coli. Exceedances were recorded for WHO drinking water quality guidelines for pH (6.25–7.93) in 2002 and for conductivity (67–306 μS cm−1) in 2002 and 2004. Total hardness values for all sachet water brands were less than 100 mg/l CaCO3 and therefore below the WHO limit for potable water. None of the samples seems to pose any health dangers as far as the major cations; sodium (17.4–19.1 mg/l), potassium (5.7–6.2 mg/l), calcium (8.0–24.0 mg/l) and magnesium (19.9–50 mg/l) are concern. Apart from nitrite, for which some exceedances were recorded and phosphate which does not have an established WHO guideline, the measured major anions (i.e., chloride: 1.57–37.7 mg/l, sulfate: 0.33–44.33 mg/l and nitrates: 0.005–0.70 mg/l) were within the WHO drinking water guideline. No exceedances were also recorded for iron and lead. In general, the high quality claimed for sachet waters could not be confirmed based on the measured physico-chemical and bacteriological properties. The variable quality and in some cases, poor water quality observed, likely reflects the fact that the sachets are not always bagged under scrutinized sanitary conditions.

Mechanisms of Boron Removal with Electrocoagulation

Environmental Context. Various environmental regulation organizations have set up standards or guidelines to regulate the boron concentration in drinking water, as a result of concern for human and animal health. In 2004, the World Health Organization Guidelines for Drinking Water Quality recommended boron values of no more than 0.5 mg L–1 in drinking water. Preliminary studies on boron removal with electrocoagulation have been carried out. However, in order to enhance boron removal using this method, and to meet the stringent guidelines set in place by the World Health Organization, there is a need to obtain a better understanding of how boron is removed from water by electrocoagulation. Abstract. This study aims to explore the mechanisms of boron removal by electrocoagulation (EC). The results demonstrate that adsorption and precipitation of boron by Al flocs are dominant mechanisms in boron removal using EC. The Al flocs that result from the EC process are found to be mainly composed of polymeric Al13 polymers (43%) and to have a long-lasting positive charge. These characteristics of the flocs contribute to the high levels of boron removal observed using EC. The maximum boron adsorption of the Al flocs is 200 mg g–1 and the solubility product constant (Ksp), which represents the boron precipitate Al(OH)2BO2·nH2O, is 2.6 × 10−40 (at 20°C).

Water safety plans for piped urban supplies in developing countries: a case study from Kampala, Uganda

The World Health Organisation (WHO) promote the use of water safety plans (WSPs) in the 3rd edition of the Guidelines for Drinking-Water Quality (2004). WSPs place an emphasis on risk assessment coupled with risk management, with simple indicators to monitor process control and periodic verification through audit and microbial indicators. A WSP was developed for the Kampala piped water supply in Uganda by the National Water and Sewerage Corporation. The use of risk maps was found to greatly aid the identification of hazardous events in the distribution system. A validation exercise was performed that showed the WSP was properly designed. The study shows WSPs can be successfully developed for utilities in developing countries and offer significant cost savings in water quality control. Senior management endorsement was found to be essential to provide the authority to develop and implement the activities required for effective water safety management.

The new WHO Guidelines: establishing comprehensive water-safety frameworks

The third edition of the WHO's Guidelines for Drinking-Water Quality has just been launched. It emphasizes monitoring water supply systems from catchment to consumer to ensure that at critical points water safety is maintained, in order to meet health-based targets.

MANAGING THE MICROBIOLOGICAL RISKS OF DRINKING WATER

The microbiological contamination of drinking water supplies can have serious health consequences for consumers, and this has been dramatically illustrated in recent years by two disease outbreaks in Canada. In this paper, some factors that can influence the microbiological quality of drinking water and its management are examined. Frameworks have been proposed that help to clarify the main elements of health risk assessment and risk management, and, in accordance with these, risks can be logically characterized, evaluated and controlled. A protocol has been developed for microbiological risk assessment and a risk management framework now guides the development of Canada's national guidelines for drinking-water quality. Monitoring of indicator organisms and the application of adequate water treatment are the primary means recommended in the Canadian guidelines to safeguard health from the presence of water-borne pathogens. Understanding the biological characteristics of microbial pathogens is necessary for assessing their impact on community health and appraising the rationale behind drinking-water testing methods and their limitations. Improvements in health surveillance, monitoring, and risk characterization and application of concepts such as multiple barriers (source-to-tap) and total quality management should contribute to better management of the microbiological quality of drinking water.

Arsenic and Heavy Metal Pollution of Soil, Water and Sediments in a Semi-Arid Climate Mining Area in Mexico

The environmental impact of arsenic and heavy metals on a 105 km2 area of the historical and recent mining site of Villa de la Paz-Matehuala, San Luis Potosi (Mexico) was evaluated. Results of soil samples reported concentrations between 19–17 384 mg kg-1 As, 15–7200 mg kg-1 Cu, 31–3450 mg kg-1 Pb and 26–6270 mg kg-1 Zn, meanwhile, the concentrations in dry stream sediment samples were found to vary between 29–28 600 mg kg-1 As, 50–2160 mg kg-1 Pb, 71–2190 mg kg-1 Cu, and 98–5940 mg kg-1 Zn. The maximum arsenic concentration in pluvial water storage ponds (265 μg L-1), near the main potential sources of pollution, exceed by 5 times the Mexican drinking water quality guideline (50 μg L-1). The arsenic concentrations in water storage ponds and stream sediments decrease as distance from the potential sources increase. A special case is the `Cerrito Blanco' area located 5 km east of Matehuala, where the highest arsenic concentration in water was found (>5900 μg L-1), exceeding by 100 times the established guideline, thus representing a severe health risk. The results suggest that arsenic and heavy metal dispersion from their pollution sources (historical and active tailings impoundments, waste rock dumps and historical slag piles), is mainly associated in this site with: (1) fluvial transportation of mine waste through streams that cross the area in W–E direction; and (2) aeolian transportation of mineral particles in SW–NE direction. Finally, control measures for pollution routes and remediation measures of the site are proposed.

REVISION AND ESTABLISHMENT OF JAPANESE DRINKING WATER QUALITY GUIDELINES FOR DI(2-ETHYLHEXYL) PHTHALATE, TOLUENE AND VINYL CHLORIDE-DIFFERENCES FROM THE LATEST WHO GUIDELINE DRAFTS-

The revision of the Japanese drinking water quality guidelines was established in May 2003. The WHO drinking water quality guidelines for the 3(rd) edition were also revised and the draft has been open to the public since last year. Most guideline values of each chemical in both Japan and WHO were quite similar; however, there are different overt values for three chemicals. In this short communication, we describe them and discuss the reason for taking the different toxicity endpoints and derivation method for these three chemicals, di(2-ethylhexyl) phthalate, toluene and vinyl chloride.

Environmental risk assessment for plant protection products

Environmental risk assessment for plant protection products

Bacterial Water Quality in the Personal Water Bottles of Elementary Students

Samples of drinking water were collected directly from the personal water bottles of students at an elementary school in Calgary, Alberta.Total and fecal coliforms and heterotrophic bacteria were enumerated using membrane filtration and agar plate count methods respectively.The Canadian Drinking Water Quality Guidelines (CWQG) criterion was exceeded for total coliform in 13.3% of 75 samples. Fecal coliform and total heterotrophic criteria were exceeded in 8.9% (of 68 samples) and 64.4% (of 76 samples) respectively.The use of personal water bottles for students in elementary classrooms is not recommended.

Drinking water quality assessment practices: an international perspective

The complexity of compliance monitoring was acknowledged by The Standards and Monitoring Committee of IWA who initiated a task force to investigate international practices. Results from an initial survey indicated that although most countries do have drinking water quality guidelines, only a few are enforcing these guidelines. It was evident that most of these countries do not incorporate analytical variability in the application of analytical results for compliance studies. A clear link between the regulator, the producer and the analyst does not exist. An effective system that assesses compliance to drinking water specifications and at the same time ensures the consumer safe and healthy water, therefore, does not exist for most consumers. In an effort to provide guidance to members of IWA, the water supplier, the analyst and the regulator, workshops should be held during the next two conferences of IWA. The output of these workshops should be guiding documents and networking opportunities that will facilitate effective and efficient skills transfer for compliance monitoring of drinking water in all the countries of the world.

New methods for the detection of viruses: call for review of drinking water quality guidelines

Drinking water supplies which meet international recommendations for source, treatment and disinfection were analysed. Viruses recovered from 100 L-1,000 L volumes by in-line glass wool filters were inoculated in parallel into four cell culture systems. Cell culture inoculation was used to isolate cytopathogenic viruses, amplify the nucleic acid of non-cytopathogenic viruses and confirm viability of viruses. Over a period of two years, viruses were detected in 23% of 413 drinking water samples and 73% of 224 raw water samples. Cytopathogenic viruses were detected in 6% raw water samples but not in any treated drinking water supplies. Enteroviruses were detected in 17% drinking water samples, adenoviruses in 4% and hepatitis A virus in 3%. In addition to these viruses, astro- and rotaviruses were detected in raw water. All drinking water supplies had heterotrophic plate counts of < 100/mL, total and faecal coliform counts of 0/100 mL and negative results in qualitative presence-absence tests for somatic and F-RNA coliphages (500 mL samples). These results call for a revision of water quality guidelines based on indicator organisms and vague reference to the absence of viruses.

Determination of Heavy Metals in Damascus Drinking Water Using Total Reflection X-Ray Fluorescence

Abstract Total reflection X-ray fluorescence spectrometry and chemical preconcentration have been applied for multi-elemental analysis of Damascus drinking water. Water was taken directly from taps of several city sectors and analyzed for the following trace elements: Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Se and Pb. The detection limits were found to be in the range of 0.1 to 0.4 µg/L. The mean levels of trace elements in the Damascus drinking water were below the World Health Organization drinking water quality guidelines.

Guidelines for Drinking-Water Quality, Second Edition, Addendum to Volume 1: Recommendations

Guidelines for Drinking-Water Quality, Second Edition, Addendum to Volume 1: Recommendations

Development of boron reduction system for sea water desalination

Since boron has been showing to induce male reproductive impediments in laboratory animals, the 1993 WHO guidelines for drinking water quality set the recommended guideline value at 0.3 mg boron/l based on the NOEL (no-observed-adverse-effect level). Since boron is not effectively removed by the conventional water treatment not only for drinking water and domestic wastewater treatment, the concentration in ambient water as well as drinking water is affected by its consumption such as for soaps and detergents in the catchment area. Boron is also affected by leaching from the surrounding geology, drinking water derived water sources affected by a weak alkali spring contains high level of boron. Since the rejection ratio of boron is extremely less than that of salts in RO membrane system applying to drinking water supply in the areas where scarce a fresh water resources, desalinated water contains higher level of boron than that of WHO drinking water quality guidelines. In order to develop of boron treatment system either fresh water or desalinated water, multi stage RO membrane treatment system has studied by using a pilot plant. The boron rejection of RO membrane depends greatly upon pH and driving pressure of RO process. However, the boron rejection does not depends upon its concentration of raw water. Therefore, it is necessary to apply multi stage RO membrane treatment system for producing a finished water that meets the WHO drinking water quality guideline level of boron. Since the secondary and third RO membrane treat less dissolved salt concentration such as observed in fresh water, the driving pressure of RO process for removing boron can operate at low pressure such as about 0.6 to 1.3 MPa. Therefore, multi stage RO membrane sea desalination process and a low pressure RO process can be recommendable for boron management with a reasonable additional cost in drinking water supply.