Drinking Water Quality Index Research Articles

A novel approach for the formulation of Modified Water Quality Index and its application for groundwater quality appraisal and grading

To overcome the deficiencies of the existing water quality indices, a re-designed quality index based on the Canadian Drinking Water Quality Index was developed as “Modified Water Quality Index” (MWQI) and applied for evaluating the groundwater quality in the drinking water sources of Bommanahalli area in Bangalore. The main modification that was made while developing the MWQI was allocating appropriate weight factors for the critical water quality input parameters. In the process of developing the revised/modified index, 30 groundwater samples were identified in the study area, 10 quality parameters, and the corresponding Bureau of Indian standards with respect to permissible drinking standards for water quality were chosen as the input quality parameters and corresponding benchmarks. This study was carried out both during the pre- and post-monsoon seasons of 2018. The results of the quality analysis interpreted that MWQI in the groundwater resources was 39.71 and 39.10, respectively, in the pre- and post-monsoon seasons. Based on the quality rank, the water quality scenario, is seen to be poor. As per MWQI value, 93.33% of the groundwater samples violate the quality index norms, that is, exceed the prescribed permissible values, failing the test. This study clearly illustrated that the MWQI explained the complete picture of water quality in a simple and extremely reliable manner and hence shows enormous promise for its application and large suitability across the globe.

Evaluation of groundwater quality and human health risks from fluoride and nitrate in semi-arid region of northern India.

Groundwater quality in the alluvial plains of Punjab has special significance and needs great attention since it is the foremost source of drinking, irrigation and industrial uses. The present research work emphasizes the integrated hydrogeochemical and chemometric statistical approaches to appraise the geochemical processes and source apportionment of the groundwater in the alluvial plains of Jalandhar district, Punjab, India. The human health risk assessment was also performed to quantify the potential non-carcinogenic impacts of nitrate and fluoride on human health through ingestion of groundwater. For this purpose, 41 groundwater samples were collected from different groundwater abstraction units and analysed for pH, electrical conductivity, total dissolved solids, total hardness, total alkalinity and major ions (Ca2+, Mg2+, Na+, K+, HCO3-, CO32-, SO42-, NO3-, F-, Cl- and PO43-) using standard protocols. Drinking water quality index and Revelle index showed that groundwater samples fall under poor to unfit water class and salinization along the south-western portion of the study region shows poor water quality. The results of the hazard index (HIingestion) show 68% and 46.34% of the groundwater samples have HI > 1 for children and adults. The non-carcinogenic health risk assessment of nitrate (NO3-) and fluoride (F-) on the local population indicated that the children are more vulnerable through direct ingestion of drinking water than adults. Piper diagram and saturation index reveal that Ca2+-Mg2+-HCO3- is the dominant hydrochemical facies and oversaturated with calcite, dolomite and aragonite minerals in the groundwater. Gibbs diagrams, chloro-alkaline indices and scatter plots show that the hydrochemistry of the groundwater is mainly governed by aquifer material interaction such as weathering of silicate, carbonate rock, halite dissolution and cation exchange process. Chemometric statistical techniques revealed that the source identification of parameters such as Ca2+, Mg2+, Na+, K+, HCO3-, CO3- and F- is originated from geogenic factors, whereas NO3-, SO42-, Cl- and PO43- are from the anthropogenic origin. Therefore, urgent and efficient measures must be taken to combat groundwater pollution and reduce human health risk in the study area.

The Storage and Water Quality Characteristics of Rungiri Quarry Reservoir in Kiambu, Kenya, as a Potential Source of Urban Water

Urbanization has caused limitations on water resources, while climate change has reduced amounts of surface water in some parts of the world. Kikuyu, a suburban area in Kiambu county, Kenya, is facing this challenge. The major challenge in the study is scarcity of potable water, resulting in inadequate water supply to Kikuyu residents. Currently, only 63.6% of the population is being supplied with water by Kikuyu Water Company, the company mandated to supply water to the area. Water demand was 2972 m3/day in 2015 and was projected to be 3834 m3/day by 2025. This has put pressure on the already exploited clean water resources, making it necessary to seek additional sources of domestic water. Storage capacity and water quality of surface water bodies, especially small reservoirs whose water can be used to ease the demand, need to be assessed for supplemental water supply. This study aimed at assessing the suitability of the abandoned quarry reservoir as a source of potable urban water by determining its storage capacity characteristics and water quality status. Volume characteristics were determined using bathymetry survey in January 2019. Water samples were collected in January and August 2019 and analyzed for chemical, physical, and bacteriological quality, as per the American Public Health Association (APHA) standard methods for water and wastewater. Parameters were evaluated based on World Health Organization (WHO) and Kenya Bureau of Standards (KEBS) guidelines for drinking water, and rated based on the drinking water quality index (WQI). The reservoir’s maximum storage capacity was found to be 128,385 m3, the surface area was 17,699 m2, and the maximum depth was 15.11 m. Nineteen of the twenty-five investigated parameters were within the acceptable standards. However, the concentrations of manganese (Mn), cadmium (Cd), iron (Fe), turbidity, total coliforms, and Escherichia coli (E. coli) were above the acceptable limits. Manganese and iron levels increased with depth. The overall WQI of the reservoir was 82.51 and 85.85 in January and August, respectively. Therefore, based on WQI rating, the water scored a good quality rating and could be used for domestic supply upon treatment. The original achievement of this study is establishment of the volume of the water in the quarry as an additional source of water to the nearby community, along with water quality status.

Spatial Distribution Analysis of Surface Water Quality Index Using Remote Sensing and GIS: A Case Study of Erandol (Maharashtra, India)

Surface water is one of the essential natural resource which support the eco-system to provide a suitable habitat to many living organisms. Monitoring of surface water gives a valuable information to evaluate the water quality problems. The objective of the present study is to evaluate status of surface water quality using drinking water quality index method and spatial distribution techniques using GIS and satellite images of Erandol area (Maharashtra, India). The integrated water samples were collected from different locations and analyzed for 13 physico-chemical characteristics which were compared with the BIS permissible limits. The WQI were calculated by using standard methods of CCMEWQI and WAWQI. The geospatial tools like high resolution multispectral remote sensing data (RESOURCESAT-2, LISS IV), GIS software, and GPS were used to perform the spatial distribution analysis using different water quality parameters. The CCMEWQI and WAWQI method indicated that the both 74% of water samples were found to be in good water quality whereas 22% and 16% of fair to poor water quality respectively. The remaining samples exhibit marginal to very poor water quality. As per WAWQI, 5% of samples found to be unsuitable for drinking and fish culture purpose during monsoon, winter and summer season. The decline in water quality was due to various anthropogenic activities including discharge of untreated sewage, enrichment of water sources through surface runoff and traditional methods of irrigation, and overuse of pesticides and inorganic fertilizer.

Using geostatistical and deterministic modelling to identify spatial variability of groundwater quality

The main portion of water demands of arid regions like Kashan Plain, Iran supply by groundwater wells. This research was conducted to assess the groundwater quality as well as modelling and mapping groundwater quality in the study area using geosatistics and deterministic techniques. Five water quality parameters, including Electrical Conductivity, Sodium Adsorption Ratio, Total Hardness, Total Dissolved Solids and pH, were applied to determine the irrigation and drinking water quality index using the Wilcox diagram and WHO standards. The final map indicated that the groundwater quality increased from north to south of the study area. The areas located in the centre, south and eastern south of the study area had the optimum quality for irrigation and drinking purposes. Furthermore, based on the results of zoning using the Wilcox diagram determined that ground water quality of the study area 22%, 42% and 36% were good, medium and non-suitable, respectively

Assessment of drinking water quality characteristics and quality index of Rajshahi city, Bangladesh

The present study on chemistry, environmetrics and quality index of 116 groundwater samples collected in pre- and post-monsoon periods in the years of 2014 and 2015 from the drought-prone Rajshahi City Corporation area, Bangladesh, is carried out for its drinking suitability from management perspective. According to the Bangladesh Drinking Water Standards (2005), parameters like pH, Ca2+, Mg2+, Cl−, Fe(total) and Mn2+ exceed the desirable limit, but within permissible limit without adverse effect except Mg2+ concentration, which accounts for 45% in pre-monsoon period and makes groundwater unsafe for drinking purposes. The groundwater belongs to alkaline earth elements (Ca2++Mg2+) and exceed alkali elements (Na++K+), and weak acids (HCO3−) exceed the strong acids (SO42−) where Ca2+ and HCO3− are dominant ions, and attribute to temporary hardness of groundwater. The groundwater of the aquifer is of Ca2+–Mg2+–HCO3− type. The source of different ions is associated with partial ion exchanges, weathering of calcareous nodules and clay minerals, flow of groundwater system through aquifer lithology, municipal sewerage, anthropogenic influence, etc. The drinking water quality index also reveals that groundwater mostly falls in ‘good’ category having suitability for drinking purposes round the year. But increasing population and water demand in the area may create threat of quality hazard in near future, and regular groundwater quality monitoring should be carried out periodically for supplying safe drinking water to city dwellers.

An integrated evaluation of groundwater quality using drinking water quality indices and hydrochemical characteristics: a case study in Jiroft, Iran

Groundwater samples were collected from 105 wells in the Jiroft aquifer in southeastern Iran in 2017 to assess the suitability of the groundwater for potable use using water quality indices including the Canadian Council of Ministers of the Environment water quality index (CCMEWQI) and the modified drinking water quality index (MDWQI). Groundwater quality was also assessed by a number of statistical methods and the use of piper diagrams. The assessment of the groundwater quality using the CCMEWQI indicated that 79% of the groundwater samples fell in the “excellent” class for drinking usage. The results of the assessment with the MDWQI indicated that all samples could be categorized as having an “excellent” quality for potable use. An assessment of the groundwater data with principal component analysis produced two principal components that accounted for 86.88% of the variance of the data. Factor 1 had strong positive loadings for Na+, Ca2+, Cl−, SO42−, TH and TDS. This factor is likely to be linked to the combined effects of aquifer mineral–groundwater reactions and the result of evaporative concentration. Factor 2 had a strong positive loading for HCO3−. HCO3− is likely to have originated from carbonate dissolution and the microbial respiration of organic carbon in the soil profile. About of 80% of the water wells that were categorized in cluster 1 were found to be suitable for drinking water usage. A piper diagram indicated that Ca2+, Na+, HCO3−+CO32− and SO42− were the dominant ions in samples that were categorized as belonging to cluster 1. In cluster 2, Na+, SO42− and Cl− were the dominant ions.

Assessment of the quality of bottled water marketed in Addis Ababa, Ethiopia

The consumption of bottled drinking water has been increasing in the world. But, the quality of bottled water used for human consumption is not subjected to any stringent quality control measure in Ethiopia. The present study was carried out to determine the physicochemical quality parameters of twenty brands of bottled drinking water available in Addis Ababa and to compare with drinking water guidelines set by World Health Organization (WHO) and Compulsory Ethiopia Standards (CES). The samples were collected by random sampling technique. The physicochemical parameters such as pH; TDS and EC; total alkalinity, total hardness, HCO 3 - , Cl - ; SO 4 2- , NO 3 - , NO 2 - , F - ) and common cations (Ca 2+ , Mg 2+ , Na + , and K + ) were determined by pH meter, conductivity meter, titration, UV-Visible spectrometry, fluoride ion selective electrode and microwave plasma-atomic emission spectrometry, respectively. The mean physicochemical concentration of TDS, total alkalinity, total hardness, HCO 3 - , SO 4 2- , NO 3 - , NO 2 - , F - , Cl - , Ca 2+ , Mg 2+ , Na + , K + , pH and EC in bottled water samples were found in the range (4.67-139), (12-165), (4-97), (16.3-202 ), (0.05-3.84), (0.02-0.84), (0.08-0.28), (0.03-1.26), (4.28-20.8), (0.19‑8.9), (0.02‑2.5), (1.8‑24.5), (0.14‑8.08 mg/L), (6.43-7.69) and (9.8-289 µs/cm), respectively. The drinking water quality index (WQI) was calculated based on 15 important quality parameters and the results were found in the range 3.85-49.2. The mean concentrations of physicochemical parameters in almost all the bottled drinking water were below the permissible limit set by WHO and CES. Hence, all the tested bottled water samples are safe for drinking purpose. KEY WORDS : Bottled water, Common cations, Common anions, Physicochemical parameters, Water quality index Bull. Chem. Soc. Ethiop. 2019 , 33(1), 21-41 DOI: https://dx.doi.org/10.4314/bcse.v33i1.3

Geospatial Distributions of Groundwater Quality in Gedaref State Using Geographic Information System (GIS) and Drinking Water Quality Index (DWQI).

The observation of groundwater quality elements is essential for understanding the classification and distribution of drinking water. Geographic Information System (GIS) and remote sensing (RS), are intensive tools for the performance and analysis of spatial datum associated with groundwater sources control. In this study, groundwater quality parameters were observed in three different aquifers including: sandstone, alluvium and basalt. These aquifers are the primary source of national drinking water and partly for agricultural activity in El Faw, El Raha (Fw-Rh), El Qalabat and El Quresha (Qa-Qu) localities in the southern part of Gedaref State in eastern Sudan. The aquifers have been overworked intensively as the main source of indigenous water supply in the study area. The interpolation methods were used to demonstrate the facies pattern and Drinking Water Quality Index (DWQI) of the groundwater in the research area. The GIS interpolation tool was used to obtain the spatial distribution of groundwater quality parameters and DWQI in the area. Forty samples were assembled and investigated for the analysis of major cations and anions. The groundwater in this research is controlled by sodium and bicarbonate ions that defined the composition of the water type to be Na HCO3. However, from the plots of piper diagram; the samples result revealed (40%) Na-Mg-HCO3 and (35%) Na-HCO3 water types. The outcome of the analysis reveals that several groundwater samples have been found to be suitable for drinking purposes in Fa-Rh and Qa-Qu areas.

Combining Spatial Analysis and a Drinking Water Quality Index to Evaluate Monitoring Data.

Drinking water monitoring is essential for identifying health-related risks, as well as for building foundations for management of safe drinking water supplies. However, statistical analyses of drinking water quality monitoring data are challenging because of non-normal (skewed distributions) and missing values. Therefore, a new method combining a water quality index (WQI) with spatial analysis is introduced in this paper to fill the gap between data collection and data analysis. Water constituent concentrations in different seasons and from different water sources were compared based on WQIs. To generate a WQI map covering all of the study areas, predicted WQI values were created for locations in the study area based on spatial interpolation from nearby observed values. The accuracy value of predicted and measured values of our method was 0.99, indicating good predication performance. Overall, the results of this study indicate that this method will help fill the gap between the collection of large amounts of drinking water data and data analysis for drinking water monitoring and process control.

Quality and Human Health Risk Assessment of Metals and Nitrogen Compounds in Drinking Water from an Urban Area Near a Former Non-Ferrous Ore Smelter

The quality and potential health risk of drinking waters in Medias, a town near a former non-ferrous ore smelter in Romania, was assessed using the drinking water quality index (DWQI), hazard quotient (HQ) and total hazard quotient (THQ). A total of 29 water samples collected from 26 wells and 3 springs used as drinking water sources, located in near proximity to agricultural, industrial or household contamination sources, were characterized. The obtained results indicated high NO2−, NO3−, Cd and Mn levels that exceeded the corresponding maximum allowable concentrations. According to the DWQI values, only 10% of water sources have acceptable quality, while 21% are threatened, and 69% have poor- quality. The health risk assessment suggested a high risk for NO3− for more than 72% of the drinking waters HQNO3− > 1.0 but no risk for metals and NO2− (HQmetals< 1.0; HQNO2−< 1.0).

Spatial distribution, exposure, and potential health risk assessment from nitrate in drinking water from semi-arid region of South India

Elevated nitrate concentration in groundwater is a worldwide problem. Continuous exposure to high levels of nitrate in groundwater may cause adverse health effects among residents who use groundwater for consumption. Therefore, this study was conducted to identify the nitrate distribution and its potential health risk assessment from semi-arid region of Peddavagu in Central Telangana (PCT), South India. Groundwater samples were collected from thirty five locations and analyzed for nitrate and other water quality parameters. Nitrate (NO3-) in groundwater was observed to vary from 17 to 120 mg/L, with a mean of 58.74 mg/L. About 57% of samples exceeded the maximum acceptable limit of Indian drinking water standard. About, 40% of groundwater samples drinking water quality index (DWQI) is good, while 60% of groundwater falls in poor quality for drinking purposes. Health risk maps were created based on hazard quotient to quantify the potential health risk of the residents using US Environmental Protection Agency (US EPA) health risk assessment model. Health risk assessment revealed that mean total hazard index (HItotal) for men, women, and children were found as 1.42E + 00, 1.67E + 00, and 1.95E + 00, respectively. Results exhibited that children are at high health risk than men and women in the PCT. Further, the human exposure to the NO3- contaminated water was above the critical limit of non-carcinogenic risk.

Protocol for the estimation of drinking water quality index (DWQI) in water resources: Artificial neural network (ANFIS) and Arc-Gis

Drinking water sources may be polluted by various pollutants depending on geological conditions and agricultural, industrial, and other human activities. Ensuring the safety of drinking water is, therefore, of a great importance. The purpose of this study was to assess the quality of drinking groundwater in Bardaskan villages and to determine the water quality index.Water samples were taken from 30 villages and eighteen parameters including calcium hardness (CaH), total hardness (TH), turbidity, pH, temperature, total dissolved solids (TDS), electrical conductivity (EC), alkalinity (ALK), magnesium (Mg2+), calcium (Ca2+), potassium (K+), sodium (Na+), sulphate (SO42−), bicarbonate (HCO3−), fluoride (F−), nitrate (NO3−), nitrite (NO2−) and chloride (Cl−) were analyzed for the purpose for this study. The water quality index of groundwater has been estimated by using the ANFIS. The spatial locations are shown using GPS. The results of this study showed that water hardness, electrical conductivity, sodium and sulfate in 66, 13, 45 and 12.5% of the studied villages were higher than the Iranian drinking water standards, respectively. Based on the Drinking Water Quality Index (DWQI), water quality in 3.3, 60, 23.3 and 13.3% of villages was excellent, good, poor and very poor, respectively.•Groundwater is one of the sources of drinking water in arid and semi-arid regions such as Bardaskan villages, which monitor the quality of these resources in planning for improving the quality of water resources.•The DWQI can clearly provide information associated with the status of water quality resources in Bardaskan villages.•The results of this study clearly indicated that with appropriate selection of input variables, ANFIS as a soft computing approach can estimate water quality indices properly and reliably.•Some parameters were in the undesirable level is some villages. Therefore, the government should try to improve the chemical and physical quality of drinking water in these areas with the necessary strategies.

Long-Term Drinking Water Quality Assessment Using Index and Multivariate Statistical Analysis for Three Water Treatment Plants of Erbil City, Iraq

Safe source of drinking water is always considered as an essential factor in water supply for cities and urban areas. As a part of this issue, drinking water quality is monitored via a useful scheme: developing drinking water quality index DWQI. DWQI is preferably used as it summarizes the whole physicochemical and bacteriological properties of a drinking water sample into a single and simple term. In this study, an evaluation was made for three drinking water treatment plants DWTPs named: Efraz 1, Efraz 2 and Efraz 3 that supply drinking water to Erbil City. The assessment was made by testing thirteen physicochemical and two bacteriological parameters during a long period of (2003 – 2017). It has been found that turbidity, electrical conductivity EC, total alkalinity, total hardness, total coliform and fecal coliform have more influence on drinking water quality. DWQI results showed that the quality of drinking water supplied by the three DWTPs in Erbil City fallen within good level. Except various occasional periods where the quality was varying from good to fair. The quality of the drinking water supply never reached the level of marginal or poor over the time investigated. The applied hierarchical clustering analysis HCA classifies the drinking water dataset into three major clusters, reflecting diverse sources of the physicochemical and bacteriological parameter: natural, agriculture and urban discharges.

A comparison between weighted arithmetic and Canadian methods for a drinking water quality index at selected locations in shatt al-kufa

Shatt Al-Kufa (Kufa River) is the major supply of surface waters in Najaf; the length and width of the river are 73 km and about 100 m respectively. In the various seasons of the year, the water level at the river is unstable, and population increases and higher living standards are likely to cause increased demand for the river water; thus, river water quality is a key concern, especially for drinking purposes.Water Quality Index (WQI) is defined as a rating reflecting the compound effects of various water quality determinants on the total quality of water. WQI is a mathematical tool used to convert large amounts of water quality data into a single number, providing a simple and explicable tool for managers and decision-makers to use to examine the quality and potential uses of a given body of water.This study is concerned with assessing an appropriate WQI for drinking use at several locations on Shatt Al-Kufa. The twelve water quality parameters of pH, Turbidity (Turb.), Electrical Conductivity (EC), Alkalinity (Alk.), Total Dissolved Solid (TDS), Total Hardness (T.H), Calcium (Ca+2), Magnesium (Mg+2), Sodium (Na+), Potassium (K+), Chlorides (Cl-1) and Sulphate (SO4) were studied over a period of ten months (January to October 2014) for nine selected locations, including Zerkh, Kufa, Manathira, Hira, Mashkhab and Qadisiya on Shatt Al-Kufa. Two methods (Weighted Arithmetic and Canadian) were applied to classify the WQI of the treated river water for drinking use, and then a comparison of the two methods was made to ascertain the difference between them.The Results of the overall and seasonal WQI according to both the Weighted Arithmetic Method and the Canadian method were classified as good (50.1 to 100 and 80 to 94, respectively) in all selected locations with the exception of certain locations in the winter season that applied to both methods.The results indicate that the difference between the two methods is very small; the high values of EC and high concentrations of SO4 were the main reasons lowering the water quality index in all locations according to both methods.

Integrated approaches to groundwater quality assessment and hydrochemical processes in Lagos, Nigeria

Integrated approaches of water quality indices, multivariate statistical analysis, and geostatistical technique were applied to examine the groundwater quality and hydrochemical processes in Lagos, Nigeria. Fifteen samples each were randomly collected from peri-urban, rural, and urban settlements totaling 45 samples from protected dug wells during dry and wet seasons. Samples were analyzed for physicochemical parameters, anion, and cation using standard method. The result shows that 95.6% of the samples during the dry season had pH below the minimum guideline for drinking water. Factor analysis explained 73.5% and 84.2% of the variance during dry and wet seasons, respectively, and extracted two factors—salinity and weathering of minerals. Gibbs plot indicates rock-weathering process as the mechanism controlling the groundwater system. Drinking water quality index shows excellent quality. Revelle index indicates that 6.6% of the samples are strongly affected by salinity during the wet season. One-quarter of sample indicate very severe corrosion based on the water stability index in both seasons. The Piper’s plot delineated four facies with primary hardness and mixed waters being the dominant during the dry and wet seasons, respectively. The study concludes that the groundwater is suitable for drinking. The study contributes to knowledge in the mapping of groundwater salinization and water stability indices and delineation of water types for information dissemination with a view to ensuring effective groundwater quality management. A policy that will ensure adequate protection of groundwater pollution from leachates, salinity, and anthropogenic impacts was recommended for sustainable groundwater use in the region.

Evaluation of groundwater quality using water quality index and its suitability for assessing water for drinking and irrigation purposes: Case study of Sistan and Baluchistan province (Iran)

ABSTRACTThe present study evaluates the groundwater quality for drinking and agricultural purposes and determines physicochemical characteristics of groundwater in the Sistan and Baluchistan province in Iran. In order to investigate the water quality, sampling was done in 654 open dug wells, the chemical parameters were analyzed, and water quality index was determined. In this regard, Langelier saturation index (LSI), Ryznar Stability index (RSI), Puckorius scaling index (PSI), Larson–Skold index (LS), and Aggressiveness index (AI) were considered to determine water suitability for industrial purposes. Finally, the analytical results were taken to generate the numerical spatial distribution of the parameters using the geographic information system (GIS) environment. According to the results, water sources were less corrosive based on AI and PSI, low and light corrosion according to RSI, and corrosion according to the Larsson–Sckold index. The results of the drinking water quality index showed that 1.2% shared extraction wells were classified as excellent, 52.1% as good, 39% as poor, 6% as very poor, and 1.7% as unsuitable for drinking purpose classes. In addition, irrigating water quality index illustrated that 19.9% and 80.1% wells were placed in the “excellent” and “Good” classes, respectively. Also, the quality of water in this study was categorized as brackish.

Evaluation of water quality suitability for drinking using drinking water quality index in Nagapattinam district, Tamil Nadu in Southern India

The overall water quality condition is explained using multiple water quality variables by developing a water quality index as a single number. The index consists of water quality variables: pH, EC, total alkalinity, total hardness, calcium, magnesium, chloride, sulphate, fluoride, nitrate, sodium, chromium, copper, iron, manganese, zinc and lead. The present study aims to assess the drinking water quality of the study area in and around Mayiladuthurai taluk using drinking water quality index system. Seventeen water quality parameters are selected for evaluation of water quality. A data set of 20 ground water samples collected from the study area in and around Mayiladuthurai taluk, Tamil Nadu is used to evaluate the quality of water samples through arithmetic and geometric index system.

Environmental quality assessment of groundwater resources in Al Jabal Al Akhdar, Sultanate of Oman

The research was conducted to assess the quality of groundwater resources of Al Jabal Al Akhdar, Oman. 11 drinking water sources were sampled during summer and winter seasons during 2012–2013 to evaluate their physico-chemical quality indicators; and assess their suitability for drinking and other domestic purposes. Sample collection, handling and processing followed the standard methods recommended by APHA and analyzed in quality assured laboratories using appropriate analytical methods and instrumental techniques. The results show that the quality parameters in all drinking water resources are within the permissible limits set by Omani and WHO standards; and the drinking water quality index is good or medium in quality based on NFS-WQI classification criteria, indicating their suitability for human consumption. There is an indication of the presence of high nitrate concentrations in some groundwater wells, which require more investigations and monitoring program to be conducted on regular basis to ensure good quality water supply for the residents in the mountain. The trilinear Piper diagram shows that most of the drinking water resources of the study area fall in the field of calcium and bicarbonate type with some magnesium bicarbonate type indicating that most of the major ions are natural in origin due to the geology of the region. This study is a first step towards providing indicators on groundwater quality of this fragile mountain ecosystem, which will be the basis for future planning decisions on corrective demand management measures to protect groundwater resources of Al Jabal Al Akhdar.

Modification of expected conflicts between Drinking Water Quality Index and Irrigation Water Quality Index in water quality ranking of shared extraction wells using Multi Criteria Decision Making techniques

Groundwater resources play a crucial role in most arid/semi-arid regions such as Karaj plain, Iran. Excavation of wells and exploiting water resources of aquifers have long been known as ordinary solutions to supply water demands for drinking, agricultural and industrial purposes. In many agricultural areas such as the above-mentioned region, extraction wells have been utilized for both drinking and agricultural consumptions, while measures taken for water quality monitoring and protecting public health are seriously limited. On the other hand, most of the shared extraction wells in the region used for drinking purpose have been located near the agricultural lands and they are highly under the risk of getting polluted by Agricultural pesticides. The current paper firstly intends to demonstrate the results obtained from Drinking water Quality Index (DWQI) as well as Irrigation Water Quality Index (IWQI) and secondly determines probable conflicts that may be aroused in ranking of water wells using these two methods Subsequently, Multi Criteria Decision Making (MCDM) techniques such as Ordered Weighted Averaging (OWA), Compromise Programing (CP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) were employed to decrease effects of the conflicts. It was clarified that MCDMs, to some extent, alleviated contradictions in wells’ ranks −determined by DWQI/IWQI- and authenticated this procedure as an appropriate method for water quality ranking in agricultural societies.