Drinking Water Quality Guidelines Research Articles

An assessment of the influence of sulfidic mine wastes on rainwater quality in a semiarid climate (SE Spain)

This study assessed the influence of the Sierra Minera de Cartagena – La Unión mining wastes on the surrounding areas, due to the sediment transport in the atmosphere. Monitoring of 15 weather stations located in the Campo de Cartagena land (SE Spain) was performed in the period December, 2004–March, 2008. A total of 920 rainfall water samples were collected and analyzed in this study. The network of weather stations covered a wide range of soil use and human activities (industrial, urban, agricultural, and mining sites). The physicochemical characterization involved determination of pH, EC, major ions, and the metals of interest in the soluble fraction of rainwater. Precipitations had an alkaline pH (7.0–7.9) and, compared to World Health Organization guidelines for drinking-water quality, samples were characterized by low EC (76–930 μS/cm), Ni (0.1–8 μg/L), Cu (3–88 μg/L), As (0.04–2 μg/L), Na+ (3–16 mg/L), K+ (0.41–30 mg/L), Ca2+ (6–51 mg/L), Mg2+ (up to 5 mg/L), Cl– (4–23 mg/L), NO3– (1–30 mg/L), and SO42− (4–35 mg/L) values. In certain locations, Zn, Cd, and Pb exceeded the guideline limits. A downward trend of H+, Zn, Cd, and Pb concentrations in total depositions was observed while the distance to the area affected by mining activities increased in the first 20 km. Rainwater quality was found to be just subtly affected by the metal-sulfide abandoned minesites, but without presenting a current threat to neither public health nor natural ecosystem. Nevertheless, greater attention should be paid in the future projections of climate change, where a significant increase in aridity may favor the atmospheric transport of pollutant particles.

Solid and Microbiological Quality Assesment of Gari within Ibadan Metropolis

The processing of cassava tuber to gari and its handling involve different stages. At each stage, there is a level of contamination by solid and microbial pathogen. The solid, micro elements and microbiological quality of gari obtained from three factories, markets and streets within Ibadan metropolis in Nigeria was investigated. Evaluation of solid particle level was carried out by sedimentation method, while micro element and microbial pathogen were determined by using appropriate media. A high level of solid (sand) was observed to range from 0.56 to 1.59%; while micro element such as cadmium 0.01 to 0.14mg/l, lead 0.04 to 0.25mg/l and chromium 0.04 to 0.35mg/l and pathogen like Aspergillius , Fusarium , Staplylococcus and Basillus were present in a range 0.00‐26.9 cfu x 10 -3 . These were found to be above WHO’s guidelines for drinking-water quality (2006). Suggestions were offered for effective processing and handling of gari in the area.

Preliminary study on the radiological and physicochemical quality of the Umgeni Water catchments and drinking water sources in KwaZulu-Natal, South Africa

Raw and potable water sample sources, from the Umgeni Water catchment areas (rivers, dams, boreholes) in central KwaZulu-Natal (South Africa), were screened for Uranium concentration and alpha and beta radioactivity. Test methods used were gas flow proportional counting for alpha-beta radioactivity, and kinetic phosphorescence analysis (KPA), for Uranium. The uranium levels (median = 0.525 μg/L, range = <0.050–5.010) were well below the international World Health Organization (WHO) (2011) guideline for drinking-water quality (≤15 μg/L). The corresponding alpha and beta radioactivity was ≤0.5 Bq/L (median = 0.084, Interquartile Range (IR) = 0.038, range = 0.018–0.094), and ≤1.0 Bq/L (median = 0.114, IR = 0.096, range = 0.024–0.734), respectively, in compliance with the international WHO limits. For uranium radionuclide, the average dose level, at uranium level of ±0.525 μg/L, was 0.06 μSv/a, which complies with the WHO reference dose level for drinking water (<0.1 mSv/a). There was a distinct trend of cluster of relatively higher Uranium levels of some sources that were found to be associated with the geology/geography and groundwater sources. Overall, the radiological water quality classification, with respect to WHO, is “Blue” – ideal; additional physicochemical analyses indicated good water quality. The analytical test methods employed were found to be suitable for preliminary screening for potential radioactive “hot spots”. The observed Uranium levels, and the alpha/beta radioactivity, indicate contribution largely from Naturally Occurring Radioactive Material (NORM), with no significant health risk to humans, or to the environment.

Problems with meeting new (10 μg/L) standard for lead in drinking water: Polish perspectives

In the current (2011) edition of ‘Guidelines for Drinking-water Quality’, the World Health Organization sets the guideline value for the concentration of lead in drinking water at 10 μg/L. This value, however, is a provisional one on the basis of treatment performance and analytical achievability. It is extremely difficult to achieve lower concentrations by central conditioning, such as phosphate dosing. Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption has set 10 μg/L as a target parametric value. The parametric value was 25 μg/L until December 2013. In Poland, the 10 μg/L standard came into force on 1 January 2013. A tap survey based on random daytime sampling (RDT) was conducted in 15 water supply zones in Poland. A total of 1440 RDT samples were collected during the period 2007–2012. The survey revealed that on average 8.4% of samples collected show lead concentrations exceeding 10 μg/L. In some water supply zones, the percentage of non-compliant samples reached 60%. This suggests that a substantial number of water companies in Poland will have to undertake significant measures to achieve proper quality standards in water supplied to consumers.

Biogeochemical Process-Based Design and Performance of a Pilot-Scale Constructed Wetland for Arsenic Removal from Simulated Bangladesh Groundwater

A pilot-scale constructed wetland treatment system (CWTS) was designed and built to produce biogeochemical conditions promoting processes targeted for removal of arsenic from simulated Bangladesh groundwater. Two CWTS series were designed to promote coprecipitation and sorption of arsenic with iron oxyhydroxides under oxidizing conditions, and two series were designed to promote precipitation of arsenic sulfide and coprecipitation of arsenic with iron sulfide under reducing conditions. Arsenic removal performance was greater in series with oxidizing conditions than in series with reducing conditions (mean outflow concentrations of 64 and 108 μg L−1, respectively). Additions of zero-valent iron (ZVI) to oxidizing series and to reducing series enhanced arsenic removal (mean removal efficiencies of 72 and 42 %, respectively) compared to unamended series (27 and 20 %, respectively). Arsenic removal performance was significantly greater (α = 0.05) in the oxidizing series amended with ZVI than in the other series, with removal extents, efficiencies, and rate coefficients ranging from 6 to 79 μg L−1, 40 to 95 %, and 0.13 to 0.77 day−1, respectively. Results from this pilot-scale study demonstrate that a CWTS can decrease concentrations of arsenic in arsenic-contaminated water to below the World Health Organization (WHO) drinking water quality guideline of 10 μg L−1.

Fate and distribution of arsenic in a process-designed pilot-scale constructed wetland treatment system

The fate and distribution of arsenic in simulated groundwater was determined in a pilot-scale constructed wetland treatment system (CWTS) designed to promote specific biogeochemical processes for arsenic removal. Two CWTS series were designed to promote co-precipitation and sorption of arsenic with iron oxyhydroxides under oxidizing conditions, and two series were designed to promote precipitation of arsenic with sulfide and co-precipitation of arsenic with iron sulfide under reducing conditions. Measured conditions in the CWTS were within ranges favorable for the targeted processes. Arsenic removal was significantly greater (α=0.05) in an oxidizing series amended with zero-valent iron (ZVI) than in the other series, with removal extents, efficiencies, and rate coefficients ranging from 6 to 79μgL−1, 40 to 95%, and 0.13 to 0.77d−1, respectively. The majority of inflow arsenic retained in the first reactor of each series partitioned to the sediment (88–99%), while the remainder partitioned to Typha latifolia. A greater percentage of inflow arsenic was retained in the sediment of the first reactor of the two oxidizing series (20 and 13%) than in the first reactor of the two reducing series (6 and 7%). Addition of ZVI enhanced arsenic removal from the aqueous phase in both oxidizing series and reducing series and increased the percentage of inflow arsenic partitioned to sediment. A vertical concentration gradient developed over time in the sediment, with 74–85% of sediment-bound arsenic accumulated in the upper 6cm and the remaining percentage below 6cm. Results from this study demonstrate that a CWTS can decrease the concentration of arsenic in simulated groundwater to below the World Health Organization (WHO) drinking water quality guideline of 10μgL−1 primarily by transferring arsenic from the aqueous phase to the sediment.

Drinking Water Quality Guidelines across Canadian provinces and territories: jurisdictional variation in the context of decentralized water governance.

This article presents the first comprehensive review and analysis of the uptake of the Canadian Drinking Water Quality Guidelines (CDWQG) across Canada’s 13 provinces and territories. This review is significant given that Canada’s approach to drinking water governance is: (i) highly decentralized and (ii) discretionary. Canada is (along with Australia) only one of two Organization for Economic Cooperation and Development (OECD) member states that does not comply with the World Health Organization’s (WHO) recommendation that all countries have national, legally binding drinking water quality standards. Our review identifies key differences in the regulatory approaches to drinking water quality across Canada’s 13 jurisdictions. Only 16 of the 94 CDWQG are consistently applied across all 13 jurisdictions; five jurisdictions use voluntary guidelines, whereas eight use mandatory standards. The analysis explores three questions of central importance for water managers and public health officials: (i) should standards be uniform or variable; (ii) should compliance be voluntary or legally binding; and (iii) should regulation and oversight be harmonized or delegated? We conclude with recommendations for further research, with particular reference to the relevance of our findings given the high degree of variability in drinking water management and oversight capacity between urban and rural areas in Canada.

Water quality laboratories in Colombia: A GIS-based study of urban and rural accessibility

The objective of this study was to quantify sample transportation times associated with mandated microbiological monitoring of drinking-water in Colombia. World Health Organization Guidelines for Drinking-Water Quality recommend that samples spend no more than 6h between collection and analysis in a laboratory. Census data were used to estimate the minimum number of operational and surveillance samples required from piped water supplies under national regulations. Drive-times were then computed from each supply system to the nearest accredited laboratory and translated into sample holding times based on likely daily monitoring patterns. Of 62,502 surveillance samples required annually, 5694 (9.1%) were found to be more than 6h from the nearest of 278 accredited laboratories. 612 samples (1.0%) were more than 24hours' drive from the nearest accredited laboratory, the maximum sample holding time recommended by the World Health Organization. An estimated 30% of required rural samples would have to be stored for more than 6h before reaching a laboratory. The analysis demonstrates the difficulty of undertaking microbiological monitoring in rural areas and small towns from a fixed laboratory network. Our GIS-based approach could be adapted to optimise monitoring strategies and support planning of testing and transportation infra-structure development. It could also be used to estimate sample transport and holding times in other countries.

Comparison of different digestion methods of green and black tea at the Sarajevo market for the determination of the heavy metal content

The content of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was determined in commercially available black and green tea from Sarajevo market. The concentrations of metals in tea infusion and solutions prepared by applying four digestion methods were determined by using FAAS. The results show that the highest concentration of total metals was obtained after acid digestion in an autoclave. The concentration of metals soluble in water obtained in tea infusion does not exceed maximum allowed values provided by WHO (Guidelines for drinking-water quality, World Health Organization, Geneva, 2011). Among the investigated metals Mn was the highest and ranged from 286 to 334 μg g−1 in tea infusion of green and black tea, respectively, to 1,078 and 1,528 μg g−1 total content of Mn in green and black tea, respectively. The concentration of heavy metals in water extracts of tea was distinctly low in comparison with the total content. The concentrations of Cd and Pb were under the determination limit using FAAS. The total content of all determined metals was higher in black tea than in green tea.

Impact of Pit Latrines on Groundwater Quality of Fokoslum, Ibadan, Southwestern Nigeria

Insufficient supply of treated water in most of the rural and peri-urban areas of Nigeria has made groundwater a major source of water supply for domestic and other purposes. In theseareas,water demand is fulfilled from shallow wells. The shallow wells are commonly constructed close to pit latrines.A study was therefore conducted to determine the impact of pit latrines on groundwater quality in Foko slum, Southwestern Nigeria. Water quality of shallow wells was assessed within the slum with respect to their distance from fivepit latrines. Water samples were collected from the shallow wells and analyzed for determination of total and faecal coliforms (FC), alkalinity, total dissolved solids (TDS), total suspended solids (TSS), nitrates, electrical conductivity, turbidity and pH.The faecal coliform values were regressed with distance between the pit latrines and the wells. The resulting equation was evaluated to obtain a minimum lateral distance between a pit latrine and shallow well for zero value of microbiological parameters in the wells. Results showed that the physico-chemical parameters of the water samples were within the World Health Organization (WHO) guidelines for drinking water quality. Nevertheless, Original Research Article British Journal of Applied Science & Technology, 4(3): 440-449, 2014 441 biological contaminants exceeded the recommendation of WHO drinking water quality guidelines. Maximum coliform counts enumerated were9300cfu/100ml of water. This study shows that there is an indicator gradient in faecal bacteria with distance from pit latrines, and that pit latrines whichimpact on shallow well water at lateral distances of 19.75m.

Selecting pesticides for inclusion in drinking water quality guidelines on the basis of detection probability and ranking

Pesticides released into the environment may pose both ecological and human health risks. Governments set the regulations and guidelines for the allowable levels of active components of pesticides in various exposure sources, including drinking water. Several pesticide risk indicators have been developed using various methodologies, but such indicators are seldom used for the selection of pesticides to be included in national regulations and guidelines. The aim of the current study was to use risk indicators for the selection of pesticides to be included in regulations and guidelines. Twenty-four risk indicators were created, and a detection rate was defined to judge which indicators were the best for selection. The combination of two indicators (local sales of a pesticide for the purposes of either rice farming or other farming, divided by the guideline value and annual precipitation, and amended with the scores from the physical and chemical properties of the pesticide) gave the highest detection rates. In this case study, this procedure was used to evaluate 134 pesticides that are currently unregulated in the Japanese Drinking Water Quality Guidelines, from which 44 were selected as pesticides to be added to the primary group in the guidelines. The detection probability of the 44 pesticides was more than 72%. Among the 102 pesticides currently in the primary group, 17 were selected for withdrawal from the group.

Hydrochemical study of water collected at a section of the Lower Volta River (Akuse to Sogakope area), Ghana

The present hydrochemical study at the Lower Volta River (Akuse to Sogakope area), Ghana was conducted by determining the physico-chemical parameters (pH, temperature, total dissolved solute, electrical conductivity, total hardness, phosphate (PO43−), nitrate (NO3−), sulfate (SO42−), dissolve oxygen (DO), biological oxygen demand, calcium (Ca2+), sodium (Na+), magnesium (Mg2+), total iron (Fe), manganese (Mn), copper (Cu) nickel (Ni), and total chromium (Cr) at 38 sampling sites during the wet and the dry seasons. The physical and ionic parameters were mostly found within the WHO (Guidelines for drinking-water quality, 3rd edn, Geneva 2004) standard for drinking water. The trace metals except Cu at some sites recorded values above the WHO (Guidelines for drinking-water quality, 3rd edn, Geneva 2004) standard for drinking water. This shows that the river water is not entirely fit for drinking. Mean values of physico-chemical parameters were mostly found to be high in the dry season as compared to the wet season. Cluster analysis (CA) and principal component analysis (PCA) were employed to evaluate the water quality and the interrelationship between variables. CA grouped the physico-chemical parameters into three groups (physical/minor ions, major ions and trace elements). Correlation analysis showed that physico-chemical parameters do not vary much in terms of the sampling sites. Thus, based on obtained information, it is possible to design a future, desirable sampling strategy, which could reduce the number of sampling stations and associated costs for effective river water quality management. Results showed that four principal components (industrial effect, domestic factor, natural source and agricultural effect) accounted for 65.59 % of the total variance among the water quality parameters. PCA also identified sampling sites 69R, 63R, 51M, 87L, 35L, 74L and 84L as polluted with metals. Therefore, water quality monitoring and control of release of industrial and anthropogenic wastes into the river are strongly needed.

Dissolved Nitrogen Survey in Groundwater Resources in Al-Ula village, Madina El Monawara, Saudi Arabia

Nitrogen contents contamination of groundwater is the subject of interest because of their hazard potential to human health. A water quality study was carried out on groundwater wells, which serves as drinking water sources in rural communities, in Al-Ula village of Madina El Monawara region, Kingdom of Saudi Arabia. The ammonia (NH3), nitrate (NO3 -) and nitrite (NO2 -) contents of water samples collected from 10 wells and 3 water sources were estimated using spectrophotometric techniques. Water samples were collected monthly from April 2012 to March 2013 and analyzed for different forms of nitrogen in water samples. Results showed that the mean concentration of ammonia, nitrate, and nitrite ranged from 0.042 to 0.0 mg/l, 2.6 to 0.6 mg/l, and 0.23 to 0.003 mg/l, respectively. The concentrations of nitrogen contents in the water samples were within the permissible limits of the World Health Organization (WHO) drinking water quality guidelines and Saudi Arabia Standards Organization (SASO). Therefore, our conclusion showed that these water resources are safe for human use.

Water Quality: Guidelines, Standards and Health: Assessment of Risk and Risk Management for Water-Related Infectious Disease

The quality of water, whether it is used for drinking, irrigation or recreational purposes, is significant for health in both developing and developed countries worldwide. In responding to this challenge, countries develop standards intended to protect public health. Recognising this, the World Health Organization (WHO) develops ‘guidelines’ that present an authoritative assessment of the health risks associated with hazards through water and of the effectiveness of approaches to their control. To date, the various WHO guidelines concerned with water ( Guidelines for drinking-water quality; Guidelines for the safe use of wastewater and excreta in agriculture and aquaculture; Guidelines for safe recreational water environments ) have been developed in isolation from one another. However, their common primary concern is for health hazards derived from excreta. Addressing their specific areas of concern together will tend to support better health protection and highlight the value of interventions closer to sources of pollution, which may otherwise be under-valued. The potential to increase consistency in approaches to assessment and management of water-related microbial hazards was discussed by an international group of experts between 1999 and 2001. These discussions led to the development of a harmonised framework, which was intended to inform the process of development of guidelines and standards. Subsequently, a series of reviews was developed and refined, which addressed the principle issues of concern linking water and health to the establishment and implementation of effective, affordable and efficient guidelines and standards. The book is based on these reviews and the harmonised framework. This book will prove invaluable to all those concerned with issues relating to microbial water quality and health, including environmental and public health scientists, water scientists, policy makers and those responsible for developing standards and regulations. This title belongs to WHO Water Series . ISBN: 9781780405889 (eBook) ISBN: 9781900222280 (Print)

Fluoride in Drinking-water

Fluoride is known to occur at elevated concentrations in a number of parts of the world where it can be a significant cause of disease. The primary focus of Fluoride in Drinking Water is the prevention of adverse health effects from excessive levels of fluoride in drinking water. The book fills the urgent need, identified for updating the WHO Guidelines for Drinking-water Quality, for information on the occurrence of fluoride, its health effects, ways of reducing excess levels and methods for analysis of fluoride in water. The draft document, produced by a working group of experts convened to consider protection from fluoride and its control, was issued for extensive review and consultation. The resultant book, which incorporates the comments received, was further peer review by experts in developed and developing countries. It is aimed at a wide range of individuals, including health workers and sanitary engineers who may require a broad introduction to the subject with more detailed guidance in some specific areas. Fluoride in Drinking-water will be an invaluable reference source for all those concerned with the management of drinking-water containing fluoride and the health effects arising from its consumption, including water sector managers and practitioners as well as health sector staff at policy and implementation levels. It will also be of interest to researchers, students, and development workers and consultants. Contents Introduction Environmental occurrence, geochemistry and exposure Human health effects Guidelines and standards Removal of excessive fluoride Analytical methods Country data on dental and skeletal fluorosis associated with exposure to fluoride through drinking water Appendix: Indices of severity of dental fluorosis

Cost‐Effective Sediment Dredge Disposal Options for Small Craft Harbors in Canada

AbstractSediment dredge disposal options were reviewed to improve cost‐effectiveness and environmental safety for dredging of coastal sediments at the Department of Fisheries and Oceans Small Craft Harbours (DFO‐SCH) program in Canada. Historically, contaminated dredge sediments exceeding federal guidelines were disposed of in nearby landfills. Recent federal regulatory changes in sediment quality guidelines adopted by provincial regulators in Canada has resulted in updates to guidelines for disposal of contaminated solids in landfills. Updates now require specific and general disposal options for contaminated dredge material destined for land‐based disposal, resulting in more expensive disposal in containment cells (if contaminated sediments exceed federal guidelines). However, as part of this study, a leachate testing method was applied to contaminated sediments to simulate migration of potential contaminants in groundwater. Using this approach, leachate quality was compared to federal freshwater criteria and drinking water quality guidelines for compliance with new regulations. Leachate testing performed on the highest sediment contaminant concentrations triggered less than 2 percent potable water exceedances, meaning that most dredge spoils could be disposed of in privately owned or provincially operated landfill sites, providing less expensive disposal options compared to containment cell disposal. Current dredge disposal practices were reviewed at 35 harbor sites across Nova Scotia and their limitations identified in a gap analysis. Improved site management was developed following this review and consultation with interested marine stakeholders. New disposal options and chemical analyses were proposed, along with improvements to cost efficiencies for management of dredged marine sediments in Atlantic Canada. © 2013 Wiley Periodicals, Inc.

Dissolved heavy metal concentrations of the Kralkızı, Dicle and Batman dam reservoirs in the Tigris River basin, Turkey

Water samples were collected at monthly intervals during 1year of monitoring from Kralkızı, Dicle and Batman dam reservoirs in the Tigris River basin to assess the concentrations of dissolved heavy metals and to determine their spatial and seasonal variations. The results indicated that dissolved heavy metal concentrations in the reservoirs were very low, reflecting the natural background levels. The lowest total metal concentrations in the three dam reservoirs were detected at sampling sites close to the dam wall. However, the highest total concentrations were observed at sites, which are located at the entrance of the streams to the reservoirs. Fe, Cr and Ni were the most abundant elements in the reservoirs, whereas Cd and As were the less abundant. The mean concentrations of dissolved metals in the dam reservoirs never exceeded the maximum permitted concentrations established by EC (European Community), WHO and USEPA drinking water quality guidelines. All heavy metals showed significant seasonal variations. As, Cd, Cr, Cu, Fe, Ni and Pb displayed higher values in the dry season, while higher values for Zn in the wet season. Cluster analysis grouped all ten sampling sites into three clusters. Clusters 1 and 2, and cluster 3 corresponded to relatively low polluted and moderate polluted regions, respectively. PCA/FA demonstrated the dissolved metals in the dam reservoirs controlled by natural sources.

Pesticide Health Risk Mapping and Sensitivity Analysis of Parameters in Groundwater Vulnerability Assessment

AbstractThe extensive use of pesticides for increasing the agricultural production is affecting the quality of groundwater. The objectives of this article are to (i) develop pesticide relative leaching ranks for well sites, (ii) develop maps for human health risks due to pesticide applications, and (iii) identify the most significant parameters in pesticide simulations for groundwater vulnerability assessment. The methods include (i) development of acifluorfen relative leaching ranks for 25 well sites using ArcPRZM‐3, (ii) development of health risk maps using model simulated maximum dissolved bentazon concentrations on the basis of USA drinking water quality guidelines, (iii) sensitivity analysis for 14 ArcPRZM‐3 input parameters using the Plackett–Burman method. ArcPRZM‐3 is a user‐friendly system for spatial modeling of pesticide leaching from surface to groundwater. Thirteen acifluorfen relative leaching potential ranks were developed in which the pesticide leaching decrease from 1 to 13. The model predicted ranks for well 34 and well 9 were 2nd and 3rd, respectively, and acifluorfen was detected in both wells during the physical monitoring. The percentages of high health risks in the agricultural areas were 48.38 and 72.72% for Randolph and Independence Counties, respectively. The most significant parameters were thickness of horizon compartment, runoff curve number of antecedent moisture condition II for cropping, soil bulk density, and total application of pesticide. The irrigation, soil permeability, and numerical dispersion could impact the pesticide leaching in soils toward groundwater. The ArcPRZM‐3 system could be efficiently applied for spatial modeling and mapping of pesticide concentrations for groundwater vulnerability assessment on a large scale.

Awareness, adoption and implementation of the water safety plan methodology: insights from five Latin American and Caribbean experiences.

Considerable effort has been made worldwide to disseminate information and provide technical assistance to encourage the adoption and implementation of the water safety plan (WSP) methodology. Described since the third edition of the World Health Organization (WHO) Guidelines for Drinking-water Quality, a WSP provides guidance for water utilities to ensure the delivery of safe drinking water and protect health. Attention is now being given to understand the success of efforts to advance adoption of the WSP methodology in the Latin America and Caribbean (LAC) region. More specifically, there is interest in knowing how early adopters developed strategies to implement the WSP methodology and what challenges exist for further implementation. To better understand adoption and implementation trends, key informants from five LAC countries were interviewed and case studies were developed to reveal the diversity of WSP approaches applied in the region. Results indicate that WSP implementation is more widespread than previously reported. Respondents affirmed that the WHO Guidelines for Drinking-water Quality are routinely used as a model for country-level drinking-water regulations, which has led to uptake of the WSP methodology. Interview respondents also revealed innovative national strategic approaches for WSP implementation.

Boron Removal by Means of Precipitation Process with Magnesium Hydroxide

The presence of boron compounds in waters increases in a continuous and parellel way to industrial development. Therefore, their harmful effects an living organisms also increases, especially on plants, since this element manifests an important micronutrient-toxic boron duality. Boron is widely distributed in the environment, mainly in the form of boric asid or borate salts. Generally speaking, this element is an important micronutrient for living organisms, but the range between deficiency and excess is narrow. For this reason, the World Health Organization (WHO) recommendsin ist Guidelines for Drinking-Water Quality, a maximum boron concentration of 0.3 mgL-1. The same norms are recommended when seawater is used as a source of water. The aim of this study to investigate the influence of different operation variables within the precipitation process of boron with magnesium hydroxide when boron stock solution is being treated. Operation variables are precipitant amount, stirring speed, contact duration, pH, temperature.