Single Water Quality Research Articles

Environmental implication identification on water quality variation and human health risk assessment in the middle and lower reaches of the Hanjiang River, China

As the longest tributary of the Yangtze River, the Hanjiang River has been a “lifeline” for the “Yangtze River Economic Belt of China”. The water quality of the middle and lower reaches of the Hanjiang River (MLHR) has received considerable attention due to environmental degradation, increasing population, and water diversion project operations during the past decade. In this study, 16 water quality parameters from 14 national water quality monitoring stations along the MLHR were collected monthly from January 2021 to December 2022. Water quality index (WQI) methods coupling multivariate statistical techniques, e.g., seasonal Mann-Kendall test (SKT) and Mantel’s test, were applied to analyze and evaluate the spatiotemporal variations of water quality under different environmental and hydrological conditions. The Hazard Quotients (HQs) were used to assess the non-carcinogenic and carcinogenic risk for adults and children via ingestion and dermal pathways. The results showed that the overall water quality in the MLHR was classified as “excellent”, with the average WQI higher than “91”, and each single water quality indicator met Class I or Class II surface water quality standards of China. Ammonia (NH3-N), Total phosphorus (TP), Permanganate (CODMn), pH, and Arsenic (As) were significantly correlated with water level variations. CODMn and TP were decisive in explaining the WQI variations of the MLHR. NH3-N, water temperature, pH, and dissolved oxygen were key parameters for explaining WQI variations in most regions of the MLHR. As, Cadmium (Cd), and Chromium (Cr) presented potential health risks in the MLHR and should warrant close monitoring due to their significant health implications. Due to the continuous construction and operation of cascade hydro-projects, the synchronous monitoring of water quality and hydrological data of the MLHR should be conducted in the future. This study provides a scientific reference for managing water quality in the MLHR and similar natural riverine water bodies.

Statistical Analysis of Wastewater at Panjapur, Trichy

Abstract This study is carried out to find wastewater quality index in treated wastewater, and Statistical analysis was done in various collected samples in sewage treatment plant, Panjappur, Trichy. This study presents a Statistical analysis of the physicochemical parameters of sewage wastewater. Nearly twenty parameters of two different months were analysed using data from physico -chemical analyses. A Continuous Waste Water Quality Index (CWWQI) was established to gauge the overall state of treated wastewater quality. By taking into account previously set quality limitation norms, the index condenses a substantial number of measured quality characteristics into a single water quality term. To identify treatment process performance, the interdependencies between the variables were determined by using Principal Component Analysis (PCA). This study presents Factor analysis to identify the pollution and its type. The methods and approaches discussed in this study offer a framework for evaluating the monitoring programme for wastewater treatment.

Application and comparison of four assessment methods for water quality of Sancha Lake in Central Sichuan Province, China

Abstract In order to analyze and compare the characteristics and applicability of different water quality evaluation methods applied to lake water quality evaluation, four monitoring sections were set up in Sancha Lake in 2019, 2020, and 2021, and 20 water quality parameters were selected. The single factor index method, the comprehensive pollution index method, the Nemerow pollution index method, and the improved Nemerow pollution index method were used to comprehensively evaluate water quality. The research results showed that the single factor index evaluation method is simple to operate and can quickly determine the water quality category by identifying the worst single water quality indicator. The comprehensive pollution index method and the Nemerow pollution index method determine the degree of water pollution based on the numerical values representing the overall pollution level of the representative water body. The evaluation results showed that except for the evaluation results of the single factor evaluation method with categories II and III, the results of other evaluation methods were all category I, indicating that the water quality was good.

Getting off the ladder: Disentangling water quality indices to enhance the valuation of divergent ecosystem services*

Many water quality valuation studies and Federal cost-benefit analyses build from pioneering work using a "water quality ladder" or a single water quality index (WQI) to characterize both current conditions and effects of policies. When policies lead to contrasting changes in valued ecosystem services like recreational fishing and swimming, analyses using a single ladder or index might obscure important underlying service trade-offs. We test for this effect using alternative approaches that separate water quality indices and value changes in distinct ecosystem services stemming from policies with small to moderate changes in water quality. The indices we test relate to nutrient loadings in Michigan's rivers, lakes, and Great Lakes. Our split-sample experiment compares economic values for treatments with two versus three quality metrics. The key distinction is that the two-index survey, like many existing studies, aggregates subindices for water contact (for swimming and boating) and fish biomass scores (for fishing) into a single WQI, whereas the three-index survey separately utilizes both. We find that changes in our index reflecting changes in fecal bacteria and water clarity are valued differently from changes in our recreational fishing index. Aggregating changes in these two distinct recreational services using a single WQI yields consistently lower benefit estimates across a range of underlying changes in our experiment. In valuation scenarios with small changes in overall water quality, the WQI-based benefit estimates can differ substantially from benefits measured by decomposing the index and valuing the disparate subindices, differences which might change balance of benefits and costs in regulatory evaluations.

Inconsistency of PCA-based water quality index – Does it reflect the quality?

The formalization of a stable water quality index (WQI) from measured hydrogeochemical parameters is essential for the identification and classification of water resources. In the principal component analysis (PCA) based WQI approach, the parameter weight is derived using either PC loading or rotated factor loading from a large number of samples pooled for WQI measurement. The PCA-based approach is paradoxical, as the calculated WQI rating of a sample would rather be dependent on the size, and composition of the population. Though this issue is well anticipated, no attempt has been made to regularize or measure the extent of WQI disagreement. In the present study, the WQI of 106 groundwater samples analyzed for 12 different hydrochemical parameters were modelled using PC loading or rotated factor loading (referred to as PCQ-1, PCQ-2, respectively) approach. Analysis reveals PCQ-1 to be positively biased in 78 % of samples and rating disagreements were evident in 9.43 % of samples. WQI of the data set was estimated using repeated (1000) random non-overlapping 2 to 5-fold data partitioning (containing 21 to 83 samples in each fold) adopting either an in-sample (test set) or out-sample (train set) modelling approach. The mean of WQI deviations in repeated resampling from the reference (i.e., using the entire dataset) has been positive in most of the samples using the PCQ-1 model, irrespective of the fold partition size. The median root mean square deviation values of the data set increased with the number of fold partitioning for in-sample calibration for both PCQ-1 and PCQ-2 approaches. The exclusion of a single water quality parameter from the PCA model can cause up to a 60 % deviation of the WQI score in some water samples. The cross-validation and Monte Carlo resampling approach can serve as a framework to test the stability of PCA-based WQI.

Research on Surface Water Quality Assessment and Its Driving Factors: A Case Study in Taizhou City, China

It is necessary to assess and analyze the factors that influence surface water since they are crucial to human activities such as agriculture, raising livestock, and industry. Previous research has mostly focused on how land use and landscape patterns affect the quality of surface waters; it has seldom addressed the industrial and agricultural production activities that are directly connected to human society. Therefore, the research area’s surface water quality was assessed by single factor index (SFI) and composite water quality index (WQI), divided into flood and non-flood periods, and water quality indicators with severe pollution and significant seasonal variations were selected; A total of 28 indicators were selected from three main factors-topography, socio-economic, and land use type-and analyzed using the Spearman correlation coefficient model. (1) SFI data reveal substantial seasonal changes in pH, DO, NH3-N, TN, and TP water quality indicators. The well-developed agricultural and aquaculture in the studied region is the primary cause of the excess TN and NH3-N concentrations; (2) The sample points’ water quality index (WQI) scores range from 50 to 80, with 62% of them having “medium” water quality; (3) The study area’s seasonal variation in water quality is primarily caused by human socio-economic activities (GDP, industrial effluent discharge, COD discharge, aquatic product quality, and the proportion of primary, secondary, and tertiary industries), as well as land use type (forest, shrubland, and cropland). Topography has little effect on the study area’s surface water quality. This study offers a fresh viewpoint on surface water quality management and driver analysis, and a new framework for managing and safeguarding aquatic ecosystems.

Nitrogen and phosphorus concentration zoning control method of surface water in the Haihe River Basin

Various uncertain influencing factors and incomprehensible mechanisms have posed daunting challenges to the management and treatment of regional surface water environment quality. The unified measures and the “one-size-fits-all” management approach limit the treatment effectiveness. Therefore, considering natural and human activities which are major factors affecting the surface water environment quality, the present study proposed a set of zoning management and control schemes for nitrogen and phosphorus concentrations in surface water based on its natural attributes. Selecting DEM, rainfall, vegetation type, soil type, and land use, and employing “grid transformation”, “data extraction”, “attribute superposition” of GIS software and “correlation analysis”, “cluster analysis”, and “principal component analysis” of SPSS software, the Haihe River Basin was divided into the prevention zone, the control zone, and the non-control zone with different natural attribute sets by the correlation coefficient R2 and the nitrogen and phosphorus pollution therein. Based on the nitrogen and phosphorus data of 276 surface water quality monitoring sites, the multiple nonlinear stepwise regression analysis was conducted to construct the relationship between a single water quality indicator and its natural attributes in the three zones. The results are of essential practical significance to surface water environment quality zoning management and survey in the Haihe River Basin. Meanwhile, it provides innovative insights into environmental zoning management in other regions.

UV/Sodium percarbonate for bisphenol A treatment in water: Impact of water quality parameters on the formation of reactive radicals

Reported herein is an investigation of the impact of water quality parameters on the formation of carbonate radical anion (CO3•−) and hydroxyl radical (HO•) in UV/sodium percarbonate (UV/SPC) system versus in UV/hydrogen peroxide (UV/H2O2) system for bisphenol A (BPA) degradation in water. Pathways of CO3•− oxidation of BPA were proposed in this study based on the evolution of direct transformation products of BPA. Observed in this study, the degradation of BPA in the UV/SPC system was slower than that in the UV/H2O2 system in the secondary effluents collected from a local wastewater treatment plant due to the significant impact of coexisting constituents in the matrices on the former system. Single water quality parameter (e.g., solution pH, common anion, or natural organic matter) affected radical formations and BPA degradation in the UV/SPC system in a way similar to that in the UV/H2O2 system. Namely, the rise of solution pH decreased the steady state concentration of HO• resulting in a decrease in the observed pseudo first-order rate constant of BPA (kobs). Chloride anion and sulfate anion played a negligible role over the examined concentrations; nitrate anion slightly suppressed the reaction at the concentration of 20 mM; bicarbonate anion decreased the steady state concentrations of both CO3•− and HO• exerting significant inhibition on BPA degradation. Different extents of HO• scavenging were observed for different types of natural organic matter in the order of fulvic acid > mixed NOM > humic acid. However, the impact was generally less pronounced on BPA degradation in the UV/SPC system than that in the UV/H2O2 system due to the existence of CO3•−. The results of this study provide new insights into the mechanism of CO3•− based oxidation and new scientific information regarding the impact of water quality parameters on BPA degradation in the sytems of UV/SPC and UV/H2O2 from the aspect of reactive radical formation, which have reference value for UV/SPC application in wastewater treatment.

Treated wastewater suitability for reuse in comparison to groundwater and surface water in a peri-urban area: Implications for water quality management

The climate change and population growth led to a severe water shortage that limits fresh water availability in some areas of Togo. Thus, the farmers of Adjougba District have no other choice than using treated wastewater as an alternative for irrigated agriculture. The purpose of this study is to compare the suitability of three types of water for uses with identification of the reliable parameters in the assessment of water suitability for irrigation and domestic purposes. The raw water quality parameters, water quality indices (WQIs) and water suitability indicators for irrigation purpose (WSI-IPs) were applied for the comparison while statistical analysis and, with some experts' consensus were used to identify reliable parameters. The results suggested that the treated wastewater is more suitable than groundwater for irrigation purpose. Treated wastewater constitutes a viable fertilizer supply and is placed like surface water from permissible to excellent classes according to WSI-IPs values. The sodium absorption ratio (SAR), electrical conductivity (EC), residual sodium carbonate (RSC), Cl− and faecal coliforms (FC) are the most reliable parameters in the detection of water suitability for irrigation purpose. EC, DO, pH, turbidity or TSS, COD or CODMn, hardness, FC, NO3−, national sanitation foundation's water quality index (NSFWQI), and overall index of pollution (OPI) are the most reliable in the detection of water suitability for domestic use. The reliable parameters identified in this study are potential candidates for the development of a single water quality index for both irrigation and domestic uses in Adjougba District. However further study will be necessary for the identification of reliable parameters and the development of a water quality index at the country scale.

Water quality assessment and pollution source analysis of Yaojiang River Basin: a case study of inland rivers in Yuyao City, China

Abstract To fully understand the water quality status of the Yuyao section in the Yaojiang River Basin, we utilized the single factor and comprehensive water quality identification index methods, as well as factor analysis in this study. The single factor water quality assessment results showed that the common parameters exceeding the standard in both the wet and dry seasons included dissolved oxygen and total nitrogen, which were inferior to the target water quality grade III by 1–6 grades. The comprehensive water quality order reaching the target grade III was Hutang River (87.5%), Changling River (50.0%), Yaojiang River (43.8%), and Linzhou River (37.5%). The comprehensive water quality in the dry season (90.0% standard-achieving rate) was better than that in the wet season (25.0% standard-achieving rate). These results suggested that the surface runoff might considerably impact water quality. The factor analysis results showed that the basin surveyed in 2018 was mainly polluted by urban sewage and agricultural sources, while the primary pollution source in 2019 was agricultural pollution. Integrated with comprehensive water quality assessment results, in this study, we demonstrated that the series of water treatment projects carried out in Yuyao City positively impacted municipal sewage treatment.

Identifying major contributors to algal blooms in Lake Dianchi by analyzing river-lake water quality correlations in the watershed

Globally intensified hazardous algal blooms (HABs) can and have already threatened public health and ecosystem services. For the hypereutrophic plateau Lake Dianchi in China, although comprehensive measures have been made regarding nutrients reduction and HABs biomass mitigation in the past decades, massive HABs are still frequently observable. HABs management strategies could hardly be successful unless relationships between the surrounding rivers’ water quality and HABs inside the lake are taken into serious consideration. This study characterized the river-lake water quality differences during 2010–2015, explored the relationships of riverine pollutants loading to lake water quality, and investigated the correlations of single and joint riverway water quality parameters to lacustrine HABs respectively via Spearman correlation analysis and multiple stepwise linear regression. Results indicated that surrounding inflow rivers displayed greater fluctuations than the lake in terms of water quality, and pollutants especially CODCr and nutrients were generally of higher concentrations in rivers that flow into Caohai and northern Waihai, than at the nearby state controlling sampling sites in the lake. Comparing to the rest of the lake, HABs in northern Waihai was much more influenced by the water quality of inflow rivers. Water temperature (WT) and SS were uniformly recognized as significant positive correlation factors between riverine water quality and lacustrine HABs, while DO as negative factor. When multiple factors were considered, WT was the predominant positive contributor to lacustrine HABs among most of the inflow rivers. Impact of riverine nutrients, however, was equivocal, due to the fact that nutrients concentrations in both rivers and the lake were already way beyond the hyper-eutrophication criteria. Taking into account multiple factors that may influence the threshold of nutrients to trigger HABs, the target nutrients limits for inflow rivers as well as Lake Dianchi itself was suggested to be much lower than previously recommended, and years of nutrients reduction efforts together with other remediation projects are required to ultimately mitigate HABs inside the lake.

Development and testing of the phytoplankton biological integrity index (P-IBI) in dry and wet seasons for Lake Gehu

Taking Lake Gehu located in the Yangtze River Delta as the research object, the phytoplankton community and environmental variables at 18 sampling sites in Lake Gehu were monitored and investigated during the dry season (March) and the wet season (July) of 2020. On this basis, the phytoplankton biological integrity index (P-IBI) was established during dry and wet periods, and the health of the lake water ecosystem was evaluated. The results showed that the P-IBI in dry and wet periods was consistent throughout Lake Gehu, and the overall water ecological health assessment results were “moderate”. To test the stability of the P-IBI, the relationships between the P-IBI, its constituent parameters and a single water quality environmental factor were analyzed through redundancy analysis (RDA). The results showed that total nitrogen, the hypermanganate index, chlorophyll a, dissolved oxygen, ammonia nitrogen, and transparency were highly correlated with the P-IBI system. Comparing the composition of the P-IBI during dry and wet periods and the relationships between the P-IBI system and water quality factors in the two hydrological periods, it was found that the parameters of the P-IBI system differed greatly between the dry and wet periods. The number of significantly related water quality factors in the dry period was greater than that in the wet period, and the two-axis characteristic values, the correlations between the P-IBI system and the water quality factors, and the cumulative percentage of the dry period were higher than those in the wet period. In conclusion, the P-IBI exhibits temporal variation between hydrological periods, and the stability of the P-IBI evaluation system during the dry season is significantly better than that during the wet season.

Storm sampling to assess inclement weather impacts on water quality in a karst watershed: Sinking Creek, Watauga watershed, East Tennessee.

Sinking Creek (HUC 06010103046), in the Watauga watershed of northeast Tennessee, is impaired due to Escherichia coli. To assess how E. coli and other water quality parameters fluctuated during storm events, water samples were collected with automated samplers during eight storms at two locations: Sinking Creek and a feeder spring. Turbidity and electrical conductivity data loggers were deployed in the creek, and dissolved oxygen (DO) was measured in situ. The presence of optical brighteners, used in detergents and an indicator of residential wastewater, was assessed using cotton fabric deployed at both sites and analyzed by an external laboratory. The Colilert Quanti-Tray method was used to process water samples for E. coli. Relationships between water quality parameters and lagged precipitation were assessed using cross-correlation. At the creek, E. coli and turbidity increased within 2h of precipitation, exceeding the single sample water quality standard of 941 cfu 100ml-1 during the storm. At the spring, E. coli became elevated more quickly than at the stream, within 30 min of precipitation, and decreased below the standard during the event. Electrical conductivity decreased within 1.5 h of the storm at the creek, and DO levels were higher at the creek than at the spring. Optical brightener analysis indicated possible presence of residential wastewater during one of two sampled storms. Targeted sampling and dye tracing are recommended to validate this hypothesis. These results may be used to inform field methods in similar storm sampling studies and will be useful in watershed restoration efforts in Sinking Creek.

Metagenomic Sequencing and Quantitative Real-Time PCR for Fecal Pollution Assessment in an Urban Watershed.

Microbial contamination of recreation waters is a major concern globally, with pollutants originating from many sources, including human and other animal wastes often introduced during storm events. Fecal contamination is traditionally monitored by employing culture methods targeting fecal indicator bacteria (FIB), namely E. coli and enterococci, which provides only limited information of a few microbial taxa and no information on their sources. Host-associated qPCR and metagenomic DNA sequencing are complementary methods for FIB monitoring that can provide enhanced understanding of microbial communities and sources of fecal pollution. Whole metagenome sequencing (WMS), quantitative real-time PCR (qPCR), and culture-based FIB tests were performed in an urban watershed before and after a rainfall event to determine the feasibility and application of employing a multi-assay approach for examining microbial content of ambient source waters. Cultivated E. coli and enterococci enumeration confirmed presence of fecal contamination in all samples exceeding local single sample recreational water quality thresholds (E. coli, 410 MPN/100 mL; enterococci, 107 MPN/100 mL) following a rainfall. Test results obtained with qPCR showed concentrations of E. coli, enterococci, and human-associated genetic markers increased after rainfall by 1.52-, 1.26-, and 1.11-fold log10 copies per 100 mL, respectively. Taxonomic analysis of the surface water microbiome and detection of antibiotic resistance genes, general FIB, and human-associated microorganisms were also employed. Results showed that fecal contamination from multiple sources (human, avian, dog, and ruminant), as well as FIB, enteric microorganisms, and antibiotic resistance genes increased demonstrably after a storm event. In summary, the addition of qPCR and WMS to traditional surrogate techniques may provide enhanced characterization and improved understanding of microbial pollution sources in ambient waters.

Advanced processed wastewater for different uses: constellations favouring future implementation of a multimodal water reuse concept

Abstract Advanced wastewater treatment is often used to produce one single water quality. In recent years, technologies have been developed that allow the production of different qualities that are fit for their purpose. These technology bundles are still not being marketed, and market requirements are unclear. Two constellations in West Basin, California and in Oman were analysed to shed light on the different constellations of actors, resource situations and institutions. The first led to the industrial reuse of several water qualities, while the second produced an application in holiday resorts, leisure and food production. A hypothetical solution was contrasted with an historical case. The analysis of the constellations showed that multi-sectoral investments and dependencies require strong cooperation arrangements and long-term agreements. Governmental institutions were revealed to be suitable for coordinating the process, especially during the initial phase, but also in view of security of supply. A (comparative) examination allows an initial, still provisional systematic overview of other constellations that favour systems with recycled water of different qualities. Further research is required to understand the welfare and distribution effects of multimodal water pricing policies and the feasibility of co-financing of agricultural irrigation and opportunities for more sustainable water reuse.

Research on a Miniature Multiparameter Water Quality Sensor Chip and a System with a Temperature Compensation Function

This paper presents a multiparameter water quality sensor chip with temperature compensation. The sensor chip was manufactured using microelectromechanical system (MEMS) technology. The surface of the chip integrated pH, dissolved oxygen (DO), ammonia nitrogen, and temperature sensors. To compensate for the solution temperature, the chip was also designed with a sandwich, plate-type serpentine Pt resistance heater. The experimental results showed that the pH sensor had a high sensitivity of 0.288 mA/pH with good linearity ( R 2 = 0.9998 ), the sensitivity of the temperature sensor was 0.949 Ω/°C, the sensitivity of the ammonia nitrogen sensor was 0.1139 mA/ppm, the sensitivity of the dissolved oxygen (DO) sensor was 2.22 μA/ppm, and the sensitivity of the temperature changes with respect to the heater power was 0.3126°C/mW. Compared with a single water quality parameter sensor, the as-prepared sensor chip could simultaneously detect multiple parameters of a water sample and had a good temperature compensation effect. Moreover, the sensor chip was small in size, rugged, and highly accurate.

Evaluation of the trophic state predicted from lab and Landsat data of western coastal water of Suez Bay, Egypt

This study aimed to compare the trophic status assessments of the western coastal waters of Suez Bay, Gulf of Suez, Egypt. The Trophic Index (TRIX) that depends on the lab-based water quality measurements of nutrients, chlorophyll-a (Chl-a) and dissolved oxygen, was compared with the Carlson trophic state index that integrates lab-based data such as NH4 or PO4 concentration with Landsat data and geographic information system (GIS) techniques. The physicochemical properties were determined, which indicated that Suez Bay was in an eutrophication state limited by both N and Si. It was suggested that the most influential activities be the industrial and domestic drains that raised the TRIX value to 5.59 with a mesotrophic state on average. Likewise, phosphorus trophic status mapping applying Carlson trophic state index showed high activity nearby drain outlets, especially at the Cabanon drain. The regression statistical model indicated a relationship between lab data of nutrients and band values extracted from Landsat images. Accordingly, the integration of remote sensing and GIS techniques with laboratory data is useful for predicting the state of water quality in the coastal areas with a single lab-based water quality parameter.

Hydrogeochemical Evaluation of Water Quality Suitable for Human Consumption and Comparative Interpretation for Water Quality Index Studies

To assess the general conditions of water quality for human consumption, specific parameters are estimated to determine its viability in terms of multiple variables, which together measure water quality through the calculation of a single water quality index. In general, many variables related to mineral and bacteriological contents of water are used to calculate these indices. This study aims to assess the feasibility and importance of a quality index for drinking water commonly used in Latin America compared to other international approaches. For this purpose, the evaluation of this index is done using two different methodologies in the same study area. Fourteen water quality parameters have been selected to calculate the index and determine the consumption conditions of 87 samples collected throughout the territory. Although it is true that there are many ways to evaluate the quality of water for human consumption, it is also necessary to assess the suitability of each methodology used for uniformity of the criteria. The results confirm that a locally used index overestimates the number of water samples evaluated as of good quality for consumption while underestimating the number of samples evaluated as not suitable for consumption. These results are beneficial for water quality management and could be used in the evaluation of the methodologies used to calculate the water quality index. In addition, it is suggested that the weights of the environmental parameters should be reconsidered in water quality assessments when the two methods considered are used.

Application of the Canadian Council of Ministers of the Environment Water Quality Index to assess and communicate monitoring data from coastal waters in Abu Dhabi, United Arab Emirates

The purpose of this research was to (1) identify an existing water quality index methodology that could be used in Abu Dhabi, United Arab Emirates, and (2) apply the water quality index to Abu Dhabi’s waters to communicate water quality conditions and track changes in conditions over time. The available monitoring data were reviewed to establish the types and frequencies of data available to populate an index, and a literature search was performed to identify and review existing water quality ind in use around the world. The Canadian Council of Ministers of the Environment Water Quality Index was selected and customized for use in Abu Dhabi. Using the Canadian Council of Ministers Water Quality Index, two different data aggregation methods were investigated for developing a single Emirate-wide Water Quality Index score. Finally, an alternative method for calculating indices when there are fewer than four parameters was investigated. Three Water Quality Indexs were developed for use in Abu Dhabi: Eutrophication Index, Microbial Index, and Heavy Metals (in sediment) Index. The Canadian Council of Ministers Water Quality Index methodology was found to be relatively easy to use and flexible as a building block for tailored indices, which are used to communicate marine water quality conditions to various stakeholders, including scientists, managers, policymakers, and the public.

Water quality prediction method based on preferred classification

Water quality monitoring and prediction are important parts of Cyber Physical Systems. Considering the complexity, diversity, and strong non-linearity of water quality data, a single water quality prediction model is difficult to have a significant effect on different data. To solve this problem, a new water quality prediction method based on the preferred classification is proposed in this study. A preferred classifier is established to integrate back propagation neural network, support vector machines for regression and long short-term memory due to the fact that these three prediction models can take into account the different characteristics of water quality data. When new data input, the proposed method preferentially selects the prediction model that is most suitable for the data, and then uses the selected model for prediction. Finally, the proposed method is applied in two actual datasets: Songhua River and Victoria Bay. Experimental results demonstrate that the water quality prediction method based on preferred classification achieves better performance than any of the three single prediction models.