Integrated Water Quality Index Research Articles

Assessment of coastal river water quality in Bangladesh: Implications for drinking and irrigation purposes.

Saltwater intrusion in the coastal areas of Bangladesh is a prevalent phenomenon. However, it is not conducive to activities such as irrigation, navigation, fish spawning and shelter, and industrial usage. The present study analyzed 45 water samples collected from 15 locations in coastal areas during three seasons: monsoon, pre-monsoon, and post-monsoon. The aim was to comprehend the seasonal variation in physicochemical parameters, including water temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), hardness, and concentrations of Na+, K+, Mg2+, Ca2+, Fe2+, HCO3-, PO43-, SO42-, and Cl-. Additionally, parameters essential for agriculture, such as soluble sodium percentage (SSP), sodium absorption ratio (SAR), magnesium absorption ratio (MAR), residual sodium carbonate (RSC), Kelly's ratio (KR), and permeability index (PI), were examined. Their respective values were found to be 63%, 16.83 mg/L, 34.92 mg/L, 145.44 mg/L, 1.28 mg/L, and 89.29%. The integrated water quality index was determined using entropy theory and principal component analysis (PCA). The resulting entropy water quality index (EWQI) and SAR of 49.56% and 63%, respectively, indicated that the samples are suitable for drinking but unsuitable for irrigation. These findings can assist policymakers in implementing the Bangladesh Deltaplan-2100, focusing on sustainable land management, fish cultivation, agricultural production, environmental preservation, water resource management, and environmental protection in the deltaic areas of Bangladesh. This research contributes to a deeper understanding of seasonal variations in the hydrochemistry and water quality of coastal rivers, aiding in the comprehension of salinity intrusion origins, mechanisms, and causes.

Groundwater quality characterization using an integrated water quality index and multivariate statistical techniques.

This study attempts to characterize and interpret the groundwater quality (GWQ) using a GIS environment and multivariate statistical approach (MSA) for the Jakham River Basin (JRB) in Southern Rajasthan. In this paper, analysis of various statistical indicators such as the Water Quality Index (WQI) and multivariate statistical methods, i.e., principal component analysis and correspondence analysis (PCA and CA), were implemented on the pre and post-monsoon water quality datasets. All these methods help identify the most critical factor in controlling GWQ for potable water. In pre-monsoon (PRM) and post-monsoon (POM) seasons, the computed value of WQI has ranged between 28.28 to 116.74 and from 29.49 to 111.98, respectively. As per the GIS-based WQI findings, 63.42 percent of the groundwater samples during the PRM season and 42.02 percent during the POM were classed as 'good' and could be consumed for drinking. The Principal component analysis (PCA) is a suitable tool for simplification of the evaluation process in water quality analysis. The PCA correlation matrix defines the relation among the water quality parameters, which helps to detect the natural or anthropogenic influence on sub-surface water. The finding of PCA's factor analysis shows the impact of geological and human intervention, as increased levels of EC, TDS, Na+, Cl-, HCO3-, F-, and SO42- on potable water. In this study, hierarchical cluster analysis (HCA) was used to categories the WQ parameters for PRM and POR seasons using the Ward technique. The research outcomes of this study can be used as baseline data for GWQ development activities and protect human health from water-borne diseases in the southern region of Rajasthan.

GIS-BASED LANDSCAPE MANAGEMENT OF THE UZH RIVER BASIN: A STRATEGY TO ENHANCE RIVER WATER QUALITY

The article includes the findings of a study on the Uzh River basin’s surface water’s quality. This region is extremely important because a fraction of it is radioactively contaminated because of the Chornobyl nuclear power plant accident. Considering this, the goal of this work was to conduct a geo-informational analysis of the state and structure of the landscapes of the Uzh River basin, to identify the surface water quality parameters of this region, and to identify potential correlations between these parameters. For this purpose, we spatially divided the territory of the basin into separate massifs, in each of which, using the method of automatic decoding, we determined the ratio of the structural components of landscapes, their disturbance by erosion processes, and compared them with ground data on the quality of surface water of the massifs. According to the salt composition, all the investigated massifs have good quality conditions. The Uzh River and its tributaries should be categorized as 4 (slightly polluted) based on the average values of the trophosaprobological state, but the extreme values in some places shifted to 5 (moderately polluted). Most of the listed toxic substances were present at average levels and, for the most part, did not exceed the permitted concentrations for category 4-slightly polluted. Extreme concentrations frequently reached category 6 (polluted), which was primarily brought on by anthropogenic activity and the buildup of radioactive materials. It was found that the degree of erosive landscape destruction and the degree of landscape stabilization significantly influence the value of the integrated water quality index. Since the collected data, a three-dimensional model was developed, allowing for accurate evaluations and projections of changes in the quality of surface water based on the structural characteristics of the land shafts. Considering that some of these territories are currently in the zone of radioactive contamination, the planning of changes in the landscape structure should be coordinated with the potential risks of surface water quality deterioration, and the model proposed in this article will have significant applied value in addressing this issue.

Long-Term Water Quality Prediction Using Integrated Water Quality Indices and Advanced Deep Learning Models: A Case Study of Chaohu Lake, China, 2019–2022

The rapid development of urban industrialization has had many negative effects on the quality of water sources around cities. Long-term prediction of water quality can be of great help to the conservation of water environment. This case tries to use several popular deep learning models, such as RNN, LSTM, MLP, and Transformer-based models to predict the long-term integrated water quality index in the Chaohu Lake area. The dataset is derived from daily monitoring data from four monitoring sites within Chaohu Lake from 2019 to 2022, and the long-term prediction performance of the model is evaluated using MAE and MSE as evaluation metrics. The experimental results showed that all models selected in this case achieved good results within the study area, but Informer performed more prominently (MSE = 0.2455, MAE = 0.2449) as the length of the prediction series increased. Our results demonstrate the effectiveness of popular deep learning models in the field of WQI prediction, especially the significant advantage of transformer-based models represented by Informer in long-term water quality prediction, which will further provide an effective modern tool for water quality monitoring and management.

A comprehensive water quality index based on analytical hierarchy process

The popular water quality index (WQI) and the recently developed integrated water quality index (IWQI) were used to evaluate the potability of 32 groundwater samples collected from Nalagarh valley, Himachal Pradesh, India. But their analytical results were surprisingly contrasting. While WQI classified 14 of the samples as ‘excellent’ and 17 as ‘good’, IWQI put all of them under ‘unsuitable’ category. This led to the development of a new index, called ‘comprehensive water quality index (CWQI)’, on the basis of analytical hierarchy process (AHP). Unit weights and sub-index values of both relaxable (that have both acceptable and permissible limits) and non-relaxable (that have only one guideline value) parameters were considered in the calculation process. Two segments were calculated: PCWQI (positive CWQI) and NCWQI (negative CWQI) with their scores varying between 0 and 1 and 0 and (−0.840), respectively. Grading of water quality from drinking perspective was done essentially with NCWQI scores, such as ‘excellent’ (when NCWQI = 0), ‘good’ (NCWQI = 0 to −0.21), ‘marginal’ (NCWQI = −0.21 to −0.42), ‘poor’ (NCWQI = −0.42 to −0.63), ‘very poor’ (NCWQI = −0.63 to −0.84) and ‘unacceptable’ (NCWQI = <−0.84). In fact, whenNCWQI = 0, higher the PCWQI, better the water quality. When two water samples had the same NCWQI score, they were graded by their respective PCWQI score. When two water samples had the same magnitudes of PCWQI and NCWQI, they were graded equally. On the basis of this classification, groundwater in majority of the study area was classified under ‘good’ category for drinking purposes in absence of an alternative source of water. Compared to WQI and IWQI, CWQI proved itself to be a robust and comprehensive technique for assessing the groundwater quality. It was hence recommended to be used universally for groundwater quality assessment.

Evaluation of hydrochemistry and identification of pollution hotspots of little Akaki river using integrated water quality index and GIS

Despite unwavering effort of the government, urban river pollution in Ethiopia has remained a worrisome phenomenon now a days. This research is conducted with a prime aim of assessing and evaluating the water quality status and identifying and mapping of the pollution hotspots in the Little Akaki River (LAR), Ethiopia by integrating the water quality index (CCME-WQI) and Geographic Information System (GIS). Accordingly, water quality samples were collected from 22 monitoring stations. The water samples were collected and analyzed for physico-chemical and heavy metal constituents using the American Public Health Association (APHA) standard methods. Most of the physico-chemical constituents analyzed have surpassed the standard guideline value of the country and World Health Organization (WHO). In addition, most of the middle (S3-S10) segments of the river is heavily polluted than the downstream segment (S11-S14) and upstream segments. Similarly, the heavy metals concentrations in the LAR have decreasing trend with Mn>Zn>Pb>Cu>Cd. On the other hand, the overall CCME-WQI modeling output ranged from 18.9 – 36.2. Accordingly, the finding of the study reveals that most water quality parameters were beyond ambient surface water quality standards and the CCME-WQI categorizes all the monitoring stations under poor water quality state. Besides, the spatial distribution of pollution in LAR shows intense deterioration at the middle segment of the river and needs a proper strategic management plan in the catchment and immediate protection and restoration of the natural ecology of the LAR. It is recommended to integrate river water pollution management and maintain ecologically to achieve healthy urban development.

Development of modified integrated water quality index to assess the surface water quality: a case study of Tuo River, China.

Water quality evaluation is an important step in water environment control and management. The water quality index (WQI) is considered to be an effective method for water quality evaluation. However, when constructing the WQI, the contribution of the lower threshold limits of water quality parameters to water quality has received little attention. The principle of the modified integrated water quality index (IWQI) is that the concentration of any water quality parameter below the lower threshold limits as well as above the upper threshold limits will lead to an increase in the overall index value. Based on the concentration of water quality parameters, the modified IWQI classified water quality into five categories, i.e., bad (> 8), poor (5-8), medium (2-5), good (1-2), and excellent (< 1). Tuo River plays a crucial role in potable and irrigation water sources of Sichuan Province, and the assessment result of modified IWQI reveals that 67.8% of samples were classified as "medium," 29% "poor," and 3.2% "bad." The high concentrations of N and P from agricultural activities and industrial wastewater are the main contributors to the deterioration of water quality in the Tuo River. Additionally, the Tuo River presents the characteristics of worse water quality in the midstream. The evaluation results of the modified IWQI are consistent with that of the conventional WQI, which proves the accuracy of the modified IWQI as a surface water quality evaluation method.

Evaluation of groundwater quality of Prayagraj city using entropy water quality index (EWQI) and new integrated water quality index (IWQI)

Evaluation of groundwater quality of Prayagraj city using entropy water quality index (EWQI) and new integrated water quality index (IWQI)

Assessment of potability of minewater pumped out from Jharia Coalfield, India: an integrated approach using integrated water quality index, heavy metal pollution index, and multivariate statistics.

The dense and industrialized populace in the mining areas of Jharia Coalfield (JCF) is plagued by a severe shortage of water supply. The unutilized pumped out coal minewater discharges may be utilized to cater to the increasing water demand of the region but it runs the risk of getting contaminated from domestic and industrial effluents. The current study aimed to assess the suitability of augmenting underground minewater for potable purposes. For this purpose, ninety underground minewater samples collected from 15 locations across JCF for the hydrological year 2019-2020 were analysed to gain an insight on the physicochemical characteristics of the minewater using an integrated approach of standard hydrochemical methods, integrated water quality index (IWQI), heavy metal pollution index (HPI), and multivariate statistical analysis. For the minewater quality to be deemed suitable for potable purposes, both IWQI (lower than 2) and HPI (lower than 30) values were considered. IWQI values of the minewater samples from the study area ranged from 1.97 to 5.08, while the HPI values ranged from 18.40 to 53.05. The pH of the samples were found to be mildly acidic to alkaline (6.5 to 8.3) with varying total hardness (149 to 719mg L-1), total dissolved solids (341 to 953mg L-1), and electrical conductivity (568 to 1389 µS cm-1), reflecting heterogeneity in underlying hydrosystems, variations in geological formations, and the influence of lithogenic and anthropogenic processes on the water chemistry of the region, which was corroborated by the principal component analysis (PCA) and hierarchical cluster analysis (HCA) of the minewater samples. Two major water types of the region were identified, viz., Ca-Mg-HCO3 and Ca-Mg-Cl-SO4. This multiparametric approach gives a holistically accurate assessment of the minewater quality, overcoming the limitations of traditional water quality indices and facilitating time-saving and effective water management practices, and sets the foundation for augmenting minewater for potable purposes to meet increasing demands.

Geospatial distribution of groundwater quality using entropy water quality index and statistical assessment: A study from a tropical climate river basin

AbstractA combination of multivariate statistical techniques and an integrated water quality index methodology was adopted to understand the genesis of major ionic composition of groundwater in a tropical river basin of South India. The present study aims to examine the hydrochemical characterisation and drinking suitability of groundwater reserves of Kallada River Basin (KRB), India by collecting samples from 31 wells during pre‐monsoon (May 2019), monsoon (September 2019), and post‐monsoon (February 2020) seasons. The findings were compared with the maximum acceptable limites prescribed by Bureau of Indian Standards (BIS 2012) and World Health Organization (WHO 2017). The study also highlights the comparison of the present work with the regional and global average cation and anion concentrations. The Principal Component Analysis (PCA) extracted three factors and the obtained results shows that Cl−, TDS, Na+, and Ca2+ ions contribute towards the moderate pollution load in groundwater. The increased population around the river basin indicates the unhygienic practices in the area and hence eco‐friendly authority steps/actions should be taken to enhance the groundwater quality of the basin. The findings of this study outlines the desire for groundwater research with a further marked focus on upgrading the quantity and quality of groundwater reserves on a global scale.

Evaluation of Groundwater Using an Integrated Approach of Entropy Weight and Stochastic Simulation: A Case Study in East Region of Beijing.

Groundwater is an important source of water in Beijing. Hydrochemical composition and water quality are the key factors to determine the availability of groundwater. Therefore, an improved integrated weight water quality index approach (IWQI) combining the entropy weight method and the stochastic simulation method is proposed. Through systematic investigation of groundwater chemical composition in different periods, using a hydrogeochemical diagram, multivariate statistics and spatial interpolation analysis, the spatial evolution characteristics and genetic mechanism of groundwater chemistry are discussed. The results show that the groundwater in the study area is weakly alkaline and low mineralized water. The south part of the study area showed higher concentrations of total dissolved solids, total hardness and -N in the dry season and wet season, and the main hydrochemical types are -Ca and -Ca-Mg. The natural source mechanism of the groundwater chemical components in Chaoyang District includes rock weathering, dissolution and cation exchange, while the human-made sources are mainly residents and industrial activities. Improved IWQI evaluation results indicate that water quality decreases from southwest to northeast along groundwater flow path. The water quality index (WQI) method cannot reflect the trend of groundwater. Sensitivity analysis indicated that the improved IWQI method could describe the overall water quality reliably, accurately and stably.

Surface water quality assessment based on the Integrated Water Quality Index in the Maozhou River basin, Guangdong, China

Rivers are a vital component of both urban and rural aquatic ecosystems, and the rapidly increasing pollution in rivers severely threatens the security of these ecosystems. In this study, the surface water quality in the Maozhou River basin, Guangdong Province, China, was assessed from 2018 to 2020 using multivariate statistical techniques and the Integrated Water Quality Index (IWQI). In addition, spatial trends in surface water quality were studied using a geographic information system. The results indicated that the water quality in 82.17% of the studied section met the Class V standard for surface water quality, with IWQI values ranging from 12.157 to 3.650. The surface water quality was clustered into eight groups and further divided into unsuitable (low quality) and suitable (acceptable quality) according to standard surface water quality thresholds (China in Environmental quality standards for surface water, 2002). Four groups (G1, G2, G3, and G4) were classified as unsuitable, because they fell short of the Class V standard for surface water quality. In these groups, industrial sewage, endogenous pollution, domestic sewage, and rainfall runoff, were the primary sources of pollution, and the main background pollutants for the water quality target of the functional zones were COD, NH3-N, TP, and LAS. The other four groups were classified as suitable. In these groups, endogenous pollution and rainfall runoff were the primary sources of pollution, and the main background pollutants for the water quality target of the functional zones were NH3-N and TP. Among them, NH3-N and LAS were recognized as responsive and sensitive to the surface water quality and spatio-temporal variability. Owing to pollution treatment and management measures undertaken by the Chinese government, the black-odorous water in the Maozhou River basin has disappeared, and the water quality in the Maozhou River basin has been maintained at the “medium and good” level. However, the surface water quality in the estuary region and the southwest tributary in the basin requires further improvement. This calls for further efforts to improve surface water quality and to properly deal with various sources of pollution in the watershed. This combined method has proved to be effective for surface water quality evaluation and management at river or basin scales. The results of this work are expected to provide a scientific foundation for aquatic ecosystem management and planning.

Impacts and social implications of landuse-environment conflicts in a typical Mediterranean watershed

In coastal watersheds, services and landuse favour coastal tourism and urbanization, depriving rural upstream of infrastructure and attention. This unbalanced management leads to an intensification of socioeconomic changes that generate a structural heterogeneity of the landscape and a reduction in the livelihoods of the rural population. The incessant dissociation between the objectives of the stakeholders triggers landuse-environment-economy conflicts which threaten to mutate large-scale development programs. Here, we used multi-assessment techniques in a Mediterranean watershed from Morocco to evaluate the effects of landuse change on water, vegetation, and perception of the rural population towards environmental issues. We combined complementary vegetation indexes (NDVI and EVI) to study long-term landuse change and phenological statistical pixel-based trends. We assessed the exposure of rural households to the risk of groundwater pollution through a water analysis supplemented by the calculation of an Integrated Water Quality Index. Later, we contrasted the findings with the results of a social survey with a representative sample of 401 households from 7 villages. We found that rapid coastal linear urbanization has resulted in a 12-fold increase in construction over the past 35 years, to the detriment of natural spaces and the lack of equipment and means in rural areas upstream. We show that the worst water qualities are linked to the negative impact of anthropogenic activities on immediately accessible water points. We observe that rural households are aware of the existence and gravity of environmental issues but act confusedly because of their low education level which generates a weak capacity to understand cause and effect relationships. We anticipate the pressing need to improve the well-being and education of the population and synergistically correct management plans to target the watershed as a consolidated system. Broadly, stakeholders should restore lost territorial harmony and reallocate landuse according to a sustainable environment-socioeconomic vision.

Environmental Health Diagnosis in a Park as a Sustainability Initiative in Cities

Environmental health diagnosis was made in a sport and recreational park in the city of Guadalajara, Jalisco, Mexico. The objective of this research was to perform an environmental diagnosis in Tucson Park; it concentrated on air quality (fine and coarse particulate matter, carbon dioxide), environmental noise, water quality of springs and a pond according to national standards, and macroinvertebrates as biological indicators of water condition, as well as phytosanitary state of wooded area. Additionally, a survey was conducted to study environmental perception. Results of the study highlighted significant statistical differences concerning the amount and size of particles for the winter and spring seasons. Noise levels within the park premises exceeded the Mexican standard. Water quality measured through general criteria of integrated water quality index (WQI) qualified the park´s analyzed springs as acceptable but to abstain its use and human consumption. Finally, the perception survey identified insecurity as the major problem, followed by the lack of lighting and effective communication of courses and workshops for the community to attend. It is one of the first environmental diagnoses in sport parks in Mexico´s Metropolitan Areas as an integrated approach of ecosystem health and wellbeing of city inhabitants.

Pollution and Ecological Risk Assessment of Potentially Toxic Elements in Natural Waters from the Ameka Metallogenic District in Southeastern Nigeria

In mining areas, several potentially toxic elements (PTEs) are often released in excess quantities into the ecosystem; thereby, predisposing both human beings and the environment to pollution risks. The current paper investigated the pollution status and ecological risks of PTEs in groundwater resources from Ameka and its environs, southeast Nigeria, using several numerical and chemometric models. Both hand-dug wells and borehole samples were analyzed. The order of abundance of the PTEs in the waters was Co > Se > Cd > Ni > Mn > Fe > Zn > As > Pb > Cu, for both hand-dug wells and borehole samples. Environmental pollution risk assessment models such as the contamination factor, contamination degree, pollution index, pollution load index, Nemerow integrated pollution index, and modified heavy metal pollution index showed that 100% of the samples were highly laden with PTEs. Similarly, the ecological risk assessment showed that 100% of the samples pose very high ecological risks. Furthermore, the water quality index and integrated water quality index jointly revealed that all the analyzed groundwater sources in this mining area were unsuitable for human consumption. Chemometric tools such as factor analysis and hierarchical cluster analysis were used to establish the inter-parameter relationships. It was realized that both geogenic and anthropogenic factors are responsible for the enrichment of the PTEs in the natural waters. Therefore, based on the overall findings of this study, adequate treatment of the polluted waters before drinking is highly recommended.

Simultaneous comparison of modified-integrated water quality and entropy weighted indices: Implication for safe drinking water in the coastal region of Bangladesh

• A new unbiased drinking water quality index has been developed. • Using the index, groundwater of coastal region of Bangladesh was classified. • A comparative assessment was done between newly developed index and entropy index. • Most of the coastal groundwater exhibited as unsuitable for drinking purposes. • The index sensitivity is very high as it considered below- and upper threshold levels. Drinking-water sources are subjected to vulnerability due to chemical contamination and health risk in the southern coastal region of Bangladesh. Different types of water quality indices are being used to express the water quality, though most of them have both advantages and limitations. In this study, we modified and proposed an integrated water quality index by principal component analysis (PCA), and compared with the entropy theory. Spatial autocorrelation index and fuzzy GIS analysis are applied to delineate the suitability of groundwater in the study area based on randomly selected 377 groundwater samples from various depths (15–300 m). This study determined 20 water quality parameters. To avoid the bias of parameter selection, PCA was performed to reduce 12 parameters loads (TDS, EC, Ca 2+ , Mg 2+ , Na + , K + , Cl − , HCO 3 − , NO 3 − , pH, PO₄ 2− , and F − ). Unlike traditional indices, both desired and tolerable limits were considered in the modified-integrated water quality index (MIWQI). The results of entropy analysis depict NO 3 − , Cl − , and Na + as the most contributing parameters influencing the groundwater quality and much emphasis should be paid on these parameters to stop further groundwater pollution. MIWQI and Entropy water quality index (EWQI) results classify 21.22% and 42.43% of water samples as good quality for drinking, respectively. The rest 79% and 58% are classified as medium to extremely poor-quality water in the study area. A significant spatial pattern was identified for both water quality indices which were positively correlated (Moran’s I > 0). The MIWQI classification system exhibited commendable outcomes compared to EWQI due to comprehensiveness. Fuzzy GIS map revealed the spatial heterogeneity of groundwater parameters showing weak spatial dependency.

Signatures of contamination, corrosivity and scaling in natural waters from a fast-developing suburb (Nigeria): insights into their suitability for industrial purposes

Ojoto and its environs are a fast-growing suburb with many emerging industries. In this area, inhabitants and industrialists exclusively rely on both surface and groundwater for their domestic and industrial purposes such that there is the need to assess the drinking quality, corrosivity and scaling coefficients of the water resources. This need formed the focus of this current work. Water samples from springs, streams, hand-dug wells and boreholes were subjected to physicochemical, corrosivity and scaling examinations. Temperature was in the range of 23–29 °C. pH analysis revealed that the samples are acidic in nature. Values of Ca, Cl, HCO3, SO4, TDS, EC, TH and Zn were below their respective maximum allowable limits for drinking water. However, Fe and Pb contaminations were observed in some samples. Based on integrated water quality index, all the samples are classified as unsuitable for drinking. However, synthetic pollution index revealed that about 50% of the samples are suitable for human consumption. Corrosivity and scaling evaluation indices such as chloride–sulfate mass ratio, Revelle index, Larson–Skold index, Ryznar stability index, Langelier index, aggressive index and Puckorius scaling index indicated that the majority of the samples have low to insignificant scaling potentials. Nevertheless, majority of the indices indicated that the natural waters have very significant corrosive tendencies and as such portend further deterioration of both domestic and industrial water quality and distribution systems in future.

Development of new integrated water quality index (IWQI) model to evaluate the drinking suitability of water

Several water quality indices are used to evaluate water suitability for potable use; however, every index has strengths and weaknesses which limits the applicability and ease of use. There is a need to develop a universally accepted water quality index (WQI) which is flexible enough to represent drinking water suitability all over world. A new water quality index has been developed. The concentration of any parameter below desirable limit as well as above permissible limit will contribute to the overall increase in the index value; therefore the index is called as Integrated Water Quality Index (IWQI). In traditional WQI, desirable or permissible limits are evaluated as the standard allowable limit but in the IWQI we consider both the limits are considered, avoiding the confusion around the adoption of standard values. Based on this concept, IWQI has been classified into 5 categories viz. excellent (<1), good (1–2), marginal (2–3), poor (3–5) and unsuitable (>5); depends on the concentration of cations (Ca, Mg, Na and K), anions (Cl, SO4 and NO3) and other parameters (pH, TDS) present in groundwater samples. The result reveals that 2% samples excellent for drinking, 39% good, 43% marginal, 8% poor and 8% unsuitable for drinking. The results are obtained at 20% deficit of its maximum permissible limit and can be adjusted per user need to alert water managers of possible human health concerns with drinking water. The water quality is mainly affected due to the industrial and agricultural inputs into the aquifer system. The North West region is influenced by anthropogenic inputs from industrial effluents, whereas the South West region is affected from agricultural runoff due to a high level of agricultural activity. The IWQI is flexible, unbiased, easy to calculate and time saving, and will provide useful information to prioritize and maintain the water quality of potable sources and reduce human health impacts from using poor-quality groundwater resources.

Application of Nemerow Index Method and Integrated Water Quality Index Method in Water Quality Assessment of Zhangze Reservoir

[Objective] Based on the water quality historical data from the Zhangze Reservoir from the last five years, the water quality was assessed by the integrated water quality identification index method and the Nemerow pollution index method. The results of different evaluation methods were analyzed and compared and the characteristics of each method were identified.[Methods] The suitability of the water quality assessment methods were compared and analyzed, based on these results.[Results] the water quality tended to decrease over time with 2016 being the year with the worst water quality. The sections with the worst water quality were the southern and northern sections.[Conclusion] The results produced by the traditional Nemerow index method fluctuated greatly in each section of water quality monitoring and therefore could not effectively reveal the trend of water quality at each section. The combination of qualitative and quantitative measures of the comprehensive pollution index identification method meant it could evaluate the degree of water pollution as well as determine that the river water was black and odorous. However, the evaluation results showed that the water pollution was relatively low.The results from the improved Nemerow index evaluation were better as the single indicators and evaluation results are in strong agreement; therefore the method is able to objectively reflect the water quality of each water quality monitoring section and is more suitable for the water quality evaluation of the reservoir.

A Gis-based system for assessing marine water quality around offshore platforms

In this study, a GIS-based system (MWQ-FES) is developed for marine water quality assessment around offshore oil platforms. The developed method consists of a fuzzy risk assessment model, a eutrophication assessment module, a heavy metal assessment module, a dynamic database, the ArcGIS Engine, and a graphical user interface (GUI). The developed GIS-based GUI system integrates the fuzzy risk calculation, eutrophication risk assessment and heavy metal risk evaluation and both spatially and visually presents the results in the form of contour maps and color-coded maps that indicate the risk levels. The assessment modules analyze a large amount of data with both spatial and temporal distributions; these data are managed by the developed system. An application of the developed MWQ-FES to a real case study in China is presented in this study. The MWQ-FES produces risk maps that depict the spatial distribution of the integrated water quality index values, the eutrophication risk level and the heavy metal risk level in the study area. The primary factors that affect the water quality are subsequently examined using the visualized results. The results of the fuzzy risk assessment model show that the general water quality status in the study area was good in Oct. 2005, May 2006, and Sept. 2007, while fair water quality occurred in May 2007. For Oct. 2005, May 2006, and Sept. 2007, the eutrophication risk levels were oligotrophic, slightly eutrophic and mesotrophic, respectively. However, the eutrophication risk level at most of the sites in May 2007 was highly eutrophic. These findings agreed with previously reported water quality variations in the study area. The heavy metal risk level in the study area exhibited a slight risk during all four investigations. As for the ecological risk in the mariculture zone near the study area, the heavy metal risk exhibited a slight risk; the eutrophication risk level ranged from eutrophic to slightly mesotrophic. A comparison with previous environmental assessment results for the same study area confirms that the developed MWQ-FES can provide a better understanding of the distribution of the water quality status and ecological risk levels. Moreover, MWQ-FES can be a useful decision-support tool for marine water quality management.