Assessment Of Surface Water Quality Research Articles

Integrated Assessment of Surface Water Quality in Danube River Chilia Branch

The Chilia branch is the north branch of the Danube River at the Romania-Ukraine border in the Danube Delta; it is a complex system with economic and ecological values. The surface water quality is a major concern and monitoring programs have been developed at the national and international level. The objective of this study was to evaluate the water quality of the Chilia branch in different sampling points from the mouth to the discharge in the Black Sea. The assessment of water quality was done at the individual level taking into account the nutrient concentrations and the standard limits for good ecological status and at integrative levels, using CCME WQI. The longitudinal distribution of Chilia branch water quality was done using GIS method. A total of 106 water samples were collected between 2013 and 2019 from five sampling points. At the individual level, the Chilia branch has a good ecological status except for its levels of total nitrogen, due to the organic nitrogen contribution in 2015. In 90% of nutrient concentrations, low values predominate and high values are considered extreme; only in 10% do high values predominate and low values are considered extreme concentrations. In equal percentages, 50% of the nutrient concentrations have a high degree of heterogeneity and the other 50% of concentration values are very close to the average values, with a high degree of homogeneity. CCME WQI method indicated that 39.93% of surface waters from the Chilia branch had an excellent quality, 45.45% a good quality, and only 14.62% a fair quality.

Assessment of surface water quality of Onuiyieke river in Imo State, Nigeria

This research aimed to assess the surface water of Onuiyieke River to ascertain its quality status. Measurements were made on samples collected from seven locations with 500ml sample bottles according to standard methods. Samples for heavy metals were collected in 250ml bottle and fixed with concentrated HN03. Descriptive analysis, variation plots, ANOVA, Duncan Multiple Range tests, Principal Components Analysis (PCA), Pearson Correlation (r) and Water Quality Index (WQI) were used to analyze data. Mean values of the parameters obtained were: Total Suspended Solids (TSS) 198.19 ± 80.93mg/L; Electrical Conductivity (EC) 331.81 ± 59.78µ; Turbidity 18.84 ± 2.22 NTU; Nitrate ions 14.77 ± 0.92mg/L; Dissolved Oxygen (DO) 6.58 ± O.22mg/L and Biological Oxygen Demand (BOD) 1.77 ± 0.10mg/L. Mean values of the Trace Metals obtained were: Iron (Fe) 1.93 ± 0.23mg/L; Magnesium (Mg)0.22 ± 0.02mg/L and Calcium (Ca) 15.15 ± 1.87mg/L while the mean value of Faecal Coliform was 1.91 ± O.10MPN/100. pH, EC, TSS, BOD, turbidity, N03-, Ammonia, Fe and Faecal coliforms exceeded the NESREA and WHO maximum permissible limits. There were significant spatial differences in levels of TDS, EC, NO3, NH3, DO and Faecal coliforms (Sig F=0.000 to 0.039) and significant temporal differences in levels of PO43- (Sig F= 0.078 to 1000) between the control and other locations at p<0.05. Four Principal Components (PCs) formed the extraction solution with a cumulative percentage variability of about 77.67%. The Water Quality Index revealed that the rating for the water quality across the sampling locations was between excellent and unsuitable. Appropriate monitoring procedures for the sustainable development of the river should also be put in place.

Assessment of surface water quality of Onuiyieke river in Imo State, Nigeria

Assessment of surface water quality of Onuiyieke river in Imo State, Nigeria

ASSESSMENT OF RIVER WATER QUALITY IN THE CITY BY HYDROCHEMICAL INDICES (THE OKHTA RIVER, ST. PETERSBURG)

The Okhta River water quality was assessed in the period 2016–2020 using the component- wise assessment method and three hydrochemical indices (Water Pollution Index (WPI), Specific Combinatorial Water Pollution Index (SCWPI), and Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI)). The component-wise assessment demonstrated that the pH was neutral or slightly alkaline, and water hardness was low. Dissolved oxygen deficit was observed at most stations during the entire research period. The content of dissolved oxygen declined downstream along the river. At the river mouth, the oxygen situation is slightly better due to the inflow of the Neva River water. The BOD5 exceeded the MPC at all sampling stations, suggesting the Okhta River water was polluted with readily oxidizable organic matter. The iron content in the water exceeded the MPC manifold. An elevated content of various forms of nitrogen was also revealed. Over the entire observation period, increased concentrations of oil products were constantly recorded (exceeding MPC more than 50‑fold in different years). The Okhta River water was characterized as “dirty” and “extremely dirty”, and the water quality was “poor” according to the calculated values of the indices – WPI, SCWPI and CCME WQI. The methodology of the little-known in Russia CCME WQI is considered separately. It was compared with the WPI and SCWPI. The relationship between the indices is clarified. The use of CCME WQI for surface water quality assessment along with SCWPI is recommended.

Ground and surface water quality assessment of Palladam Taluk using Geographical Information System and Modified National Sanitation Foundation -Water Quality Index

In this work, the assessment of surface and ground water quality of Palladam Taluk, Tiruppur, district, Tamil Nadu, India were carried out using Geographical Information System (GIS) and Modified National Sanitation Foundation -Water Quality Index (MNSF-WQI). Four samples from surface and twenty seven samples from ground water sources were taken from Palladam Taluk, Tiruppur District. In the current study, the surface and ground water samples were analysed for temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), biological oxygen demand (BOD), turbidity, total dissolved solids (TDS), total hardness (TH), faecal coliforms (FC), total phosphate (TP), total nitrate (TN), chlorides (Cl-), sodium (Na+) and fluoride (F-) ions to investigate the suitability of surface and ground water for drinking and agricultural purposes through Geographic information system (GIS) and modified national sanitation foundation water quality index (MNSF-WQI) technique. The concentrations of TH, TDS, Cl- and Na+ were observed to be above the desirable limit of World Health Organization (WHO) guidelines and Bureau of Indian Standards (BIS). whereas F-, BOD, DO, EC, TP, TN, FC and temperature were within the acceptable limits. The GIS-based WQI map analysis indicated that 45% of the study area having good water quality index and the remaining area showed medium quality water. Dyeing and textile industries in the study area are responsible for deteriorating the quality to medium quality of water which was not appropriate for direct utilization and needed prior treatment. There is no detailed report on assessment of the surface and ground water quality of Palladam Taluk in Tamil Nadu using GIS and MNSF-WQI techniques.

Long-Term Assessment of Surface Water Quality in a Highly Managed Estuary Basin.

Anthropogenic developments in coastal watersheds cause significant ecological changes to estuaries. Since estuaries respond to inputs on relatively long time scales, robust analyses of long-term data should be employed to account for seasonality, internal cycling, and climatological cycles. This study characterizes the water quality of a highly managed coastal basin, the St. Lucie Estuary Basin, FL, USA, from 1999 to 2019 to detect spatiotemporal differences in the estuary’s water quality and its tributaries. The estuary is artificially connected to Lake Okeechobee, so it receives fresh water from an external basin. Monthly water samples collected from November 1999 to October 2019 were assessed using principal component analysis, correlation analysis, and the Seasonal Kendall trend test. Nitrogen, phosphorus, color, total suspended solids, and turbidity concentrations varied seasonally and spatially. Inflows from Lake Okeechobee were characterized by high turbidity, while higher phosphorus concentrations characterized inflows from tributaries within the basin. Differences among tributaries within the basin may be attributed to flow regimes (e.g., significant releases vs. steady flow) and land use (e.g., pasture vs. row crops). Decreasing trends for orthophosphate, total phosphorus, and color and increasing trends for dissolved oxygen were found over the long term. Decreases in nutrient concentrations over time could be due to local mitigation efforts. Understanding the differences in water quality between the tributaries of the St. Lucie Estuary is essential for the overall water quality management of the estuary.

Assessment of Surface Water Quality in the Podu Iloaiei Dam Lake (North-Eastern Romania): Potential Implications for Aquaculture Activities in the Area

The Podu Iloaiei Dam Lake located on the Bahluet River from Bahlui hydrographic basin, north-eastern Romania, is one of the most important water resources used for aquaculture activities in the region of interest. In the present study, the chemical composition related to water-soluble ions and elements was assessed in both water and sediment samples collected from the area of interest during July 2017 and October 2017, representative months for warm and cold seasons, respectively. Water-soluble ions (H3C2O2−, HCO2−, C2O42−, F−, Cl−, NO2−, Br−, NO3−, SO42−, Li+, Na+, NH4+, K+, and Ca2+) were analyzed by ion chromatography, while inductively coupled plasma mass spectrometry was used to quantify water-soluble fractions of elements (Be, B, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Mo, Ru, Pd, Ag, Cd, Sn, Sb, Te, Ba, Ir, Tl, Pb, Bi, and U). Evidence was obtained on the contributions of both anthropogenic and natural (pedologic) related sources in controlling the chemical composition of the water and sediment samples in the area. Analysis of Piper diagrams revealed the existence of CO32−/HCO3− and Ca2+/Mg2+ as dominant species for the sediment samples. The interest water pool was found to be oligotrophic over the warm period and eutrophic over the cold period. Overall, abundances and the association of chemical species in the area seemed to be controlled by a complex interplay between the water body’s main characteristics, meteorological factors, and anthropogenic activities. Moreover, the present results suggest that precautions should be taken for physicochemical parameter monitoring and prevention acts for surface water quality assurance in order to control the potential negative influence of some chemical parameters on fish productivity. Reported data also have a high potential to be used by experts in the field of developing lake water management policies for a sustainable exploitation of various aquatic systems.

Екологічна оцінка Запорізького (Дніпровського) водосховища

Environmental assessment of water is an integral part of monitoring water bodies. It provides information about water as a component of the aquatic ecosystem, the habitat of hydrobionts and an essential part of the natural environment, which is necessary for establishing environmental standards for water quality and adoption of measures to improve the ecological state of water bodies. Assessment of the quality of the ecological environment is an important parameter of sustainable development, necessary for the rational use of nature. Currently, the Zaporizhzhia (Dnipro) reservoir is exposed to increased anthropogenic impact, which affects water quality. The ecological state of the reservoir is deteriorating, and mass algal bloom is observed. The work aims to provide an integrated environmental assessment of water quality in different sites of the Zaporizhzhia reservoir. The study was conducted in 2019 at 5 sites along the course of the Zaporizke reservoir, which differ in hydrological and hydrochemical conditions: Samara Bay, Festivalnyi pier, Monastyrsky island, creek of the Mokra Sura river and the lower section of the reservoir (near Viyskove village), following generally accepted hydrobiological methods. The article calculates block indices and provides an environmental assessment of the water quality of the Zaporizhzhia reservoir according to the "Methodology for environmental assessment of surface water quality in the corresponding categories. The assessment of water quality by the criteria of contamination with salt composition components indicates that the water body condition is good at most of the studied points. The worst indicators were recorded in Samara Bay, where increased mineralization is observed for a long time. The trophic-saprobological block revealed to have the worst indicators and a high amplitude of index fluctuations. No significant deviations were observed in terms of the content of toxic and radiation exposure indicators throughout the entire studied water area, which makes it possible to assign water to the same class. It has been determined that the water quality of the Zaporizhzhia reservoir according to the average annual data is characterized as "good" in terms of the state and "clean, fairly clean" in terms of purity degree. However, during the study period, significant deviations from the average were observed, especially in the summer. There is a need for systematic monitoring of the reservoir, the establishment of annual dynamics, which will make it possible to determine the causes of deteriorating water quality and develop ways to address them.

The applications of Canadian water quality index for ground and surface water quality assessments of Chilanchil Abay watershed: The case of Bahir Dar city waste disposal site

Abstract Surface water and groundwater have been experiencing increasing risks of contamination in recent years because of the poor management of the immense amounts of waste created by different human activities. Inappropriate dump sites have served for many years as marginal disposal sites for a wide range of wastes, including solid waste, fresh sewage and hazardous waste, in developing nations such as Ethiopia. Physical, anthropogenic and organic procedures continuously interact to deteriorate the waste. One of the results of these practices is artificially contaminated leachate, which is potentially hazardous waste from disposal sites. If not managed appropriately, such a dumping site can contaminate groundwater (through leachates) and surface water (through contaminant transport by flooding and groundwater movement). Along these lines, this study focuses on the applications of water quality index in the ground and surface water quality caused by the waste disposal site of Bahir Dar city within the Chilanchil Abay during the study period. Water testing was performed on five samples of surface water and six samples of groundwater in each month from 30th March (dry season) to 20th August (wet season). More than 13 water quality parameters, for example, pH, TDS, electrical conductivity, turbidity, temperature, dissolved oxygen (DO), TH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), TC, NO3−, PO43−, Cr, Mn, and Pb contents, were examined in both ground and surface water. It was discovered that water quality status of the Chilanchil Abay watershed ranges from 15.87 to 36.6 for surface water and 42 to 46.2 for groundwater suggesting poor and marginal status for drinking water purpose.

Hydrogeochemistry and surface water quality assessment of IB valley coalfield area, India

Coal mining and ancillary activities have the potential to cause water pollution characterized by acid mine drainage, acid mine leachates, extreme pH conditions and heavy metal contaminations. In the present work, 33 water samples in premonsoon and 34 water samples in monsoon were collected from the surface water bodies of Ib Valley coalfield, India for hydrogeochemical analysis. In premonsoon, pH, TSS, Turbidity, DO, BOD, COD, Magnesium, Cadmium, Selenium, Nickel, Aluminum and in monsoon, pH, TSS, Turbidity, DO, BOD, COD, Iron, Cadmium, Selenium, Nickel and Aluminum were nonconforming to the permissible limit set by the Bureau of Indian Standards, World Health Organisation and Ministry of Environment, Forest and Climate Change, Government of India. The average BOD/COD ratio of less than 0.6 in both seasons indicated Ib valley coalfield water was not fairly biodegradable. The analysis of variance (ANOVA) revealed that significant seasonal variation (p < 0.05) was observed in the hydro-chemical parameters viz. TSS, turbidity, redox potential, acidity, total hardness, bicarbonate alkalinity, chloride, sulfate, nitrate, sodium, calcium, magnesium, iron, cadmium, chromium and magnesium during the entire sampling period. Whereas, no significant seasonal variation (p > 0.05) was observed in pH, EC, TDS, DO, BOD, residual chlorine, COD, oil and grease, fluoride, potassium, zinc, copper, selenium, nickel, aluminum, boron, silica, temperature, salinity, cyanide and phenol. Water Quality Index revealed that 39.39% and 35.29% samples belong to poor water quality category in premonsoon and monsoon, respectively. As per Heavy Metal Pollution Index, Degree of Contamination (Cd) and Heavy metal evaluation index, medium degree of pollution were exhibited by 51.52%, 30.30% and 45.45% samples in premonsoon and 20.59%, 35.29% and 26.47% samples in monsoon. Whereas, 5.88%, 2.94% and 5.88% samples were having high degree of pollution in monsoon and 15.15% samples caused high degree of pollution with respect to Cd in premonsoon. However, EC, Na%, PI, SAR and RSC values suggested that the water can be used for irrigation. Water type of the region had been found to be Ca–Mg–Cl–SO4 by Piper diagram.

Integration of Water Quality Indices and Multivariate Modeling for Assessing Surface Water Quality in Qaroun Lake, Egypt

Water quality has deteriorated in recent years as a result of rising population and unplanned development, impacting ecosystem health. The water quality parameters of Qaroun Lake are contaminated to varying degrees, particularly for aquatic life consumption. For that, the objective of this work is to improve the assessments of surface water quality and to determine the different geo-environmental parameters affecting the lake environmental system in Qaroun Lake utilizing the weighted arithmetic water quality index (WAWQI) and four pollution indices (heavy metal pollution index (HPI), metal index (MI), contamination index (Cd), and pollution index (PI), that are enhanced by multivariate analyses as cluster analysis (CA), principal component analysis (PCA), and support vector machine regression (SVMR). Surface water samples were collected at 16 different locations from the lake during years 2018 and 2019. Thirteen physiochemical parameters were measured and used to calculate water quality indices (WQIs). The WQIs of Qaroun Lake such WAWQI, HPI, MI, Cd, PI revealed a different degree of contamination, with respect to aquatic life utilization. The WQIs result revealed that surface water in the lake is unsuitable, high polluted, and seriously affected by pollution for an aquatic environment. The PI findings revealed that surface water samples of Qaroun Lake were significantly impacted by Al, moderately affected by Cd and Cu, and while slightly affected by Zn due to uncontrolled releases of domestic and industrial wastewater. Furthermore, increasing salinity accelerates the deterioration of the lake aquatic environment. Therefore, sewage and drainage wastewater should be treated before discharging into the lake. The SVMR models based on physiochemical parameters presented the highest performance as an alternative method to predict the WQIs. For example, the calibration (Val.) and the validation (Val.) models performed best in assessing the WQIs with R2 (0.99) and with R2 (0.97–0.99), respectively. Finally, a combination of WQIs, CA, PCA, and SVMR approaches could be employed to assess surface water quality in Qaroun Lake.

Using multivariate statistical analysis in assessment of surface water quality and identification of heavy metal pollution sources in Sarough watershed, NW of Iran.

The Sarough watershed in NW Iran hosts a large amount of mineral occurrences and ore deposits which may be considered as the source of heavy metals in the region. The area has been studied previously; however, the methodology of this paper was less focused on previous studies. This study aimed to assess water quality, determine the spatial distribution pattern, and identify the sources of heavy metals in the main tributaries of Sarough watershed using pollution indexes, multivariate statistical methods, and processing data by geographic information system. Totally, 51 water samples were collected along the main rivers to determine the concentrations of heavy metals by ICP-MS. Regarding the drinking water, agriculture, and freshwater aquatic life guidelines, the rivers were assumed unsafe considering most of toxic elements' content, especially As. The mean values for heavy metal pollution indexes (HPI: 237.32) and metal indexes (MI: 25.37) indicated the intensive heavy metal pollution. The cluster analysis categorized the 51 sampling sites into four clusters with respect to pollution level. The results obtained from the Kruskal-Wallis and multiple comparison tests had the harmony with the results of CA in introducing the most impacted sampling sites and the parameters responsible for water quality degradation. The results of PCA showed the maximum similarity between As, Sb, Se, Fe, and Mn as well as base metals which was attributed to anthropogenic input from mining and mineral processing wastes. Association of Cr and Ni may suggest a lithology source (weathering of metamorphosed ultramafic outcrops). The maps prepared in the GIS system showed the spatial distribution pattern of toxic elements with maximum values nearby mining sites which decreases gradually toward downstream areas. Finally, the results showed that the Sarough River and its tributaries are influenced by high concentrations of heavy metals from the drainages of mining and ore processing sites and naturally occurring metal loadings as well as the geogenic sources such as weathering of geologic formations and hot springs.

A comprehensive evaluation of surface water quality and potential health risk assessments of Sisa river, Kumasi

Surface water quality deterioration is one of the primary issues of the twenty-first century due to the high demand for drinking and irrigation purposes in most communities. The purpose of this study was to investigate the suitability of the Sisa river in Kumasi Metropolis, as well as the critical factors affecting its water quality and human health risk among children and adults. The findings indicated that the surface water was alkaline and, in some samples, turbidity, alkalinity, color, microbial, Fe, and Cr concentrations exceeded the standard permissible limits of WHO. Water from individual sampling sites contained Escherichia coli, total, and fecal coliform counts. There was no strong significant correlation among the levels of the heavy metals, suggesting their lack of control in their distribution, source, and transport pathway. Principal component analysis (PCA) revealed three factors that account for about 98.86 % of the total variance in the surface water quality data set. Moreover, PCA findings revealed that geogenic and anthropogenic sources were responsible for variations in physicochemical and microbiological parameters of the study area. Fe and Cr were found to have high toxic levels among the heavy metals analyzed. The heavy metal assessment index indicated moderate to high hazards. Cu had a hazard index greater than one at Duase and Atonsu, indicating a possible non-carcinogenic risk. The overall carcinogenic risk values were greater than 10−6, indicating the possibility of cancer. Water quality index values ranging from 97.95 to 137.22 percent showed that about 75 % of the samples were of poor quality. Based on these results, we recommended proper water management strategies and policies should be implemented as soon as possible to manage and protect the water resources.

Surface water quality assessment in the semi-arid area by a combination of heavy metal pollution indices and statistical approaches for sustainable management

The current study consists of evaluating surface water pollution using an integrated approach based on pollution assessment indices and statistical approaches (principal component analysis (PCA), logistic regression (LR) analysis, and cluster analysis (CA)). Thirty-four water samples from the High Ziz basin (semi-arid area), occupied by abandoned mine sites in SE Morocco, were collected and analysed for physicochemical parameters and heavy metals (Cu, Zn, Fe, Pb, Ni, and Cd). The mean concentrations of Pb, Zn, Cu, and Fe in the water samples were 41.9 mg/L, 14.8 mg/L, 20.1 mg/L, and 8.1 mg/L, respectively. The large part of the samples is in a near neutral high metal zone based on the plot of heavy metals (Fe+Cu+Pb+Zn+Ni) versus pH. The HPI, HEI, and CI pollution indices were found to average around 586.2, 321.8, and 315.8 respectively, these show strong correlations with heavy metals. The HPI, CI, and HEI values were above 100 as critical pollution index value. These indices indicate that the surface water samples are critically polluted with respect to studied heavy metals. Therefore, the high metal content of the studied samples should be of great concern for the irrigation activity. Moreover, the water quality index (WQI) shows that 76% of the water samples are unsuitable for drinking. The CA analysis grouped 34 samples into four clusters according to the similarity proprieties observed in water quality. Furthermore, the total variance is explained by 75.7% of the water quality with four components according to PCA analysis. Based on LR analysis, the hazard area is strongly correlated with the river system near abandoned mine sites, agricultural and urban areas. The water quality in the study area is controlled by natural/geogenic processes according to the interpretation of pollution indices and statistical approaches (PCA, CA, and LR). The distribution intensity of Pb, Zn, Cu, and Fe metals in the study area's surface water constitutes an environmental concern and needs a monitoring network for sustainable water resources management.

Quality Assessment of Surface Water for Domestic and Agricultural Purposes Using Hydro-chemical and Microbial Studies in Kilifi County, North Coast Region of Kenya

Water has economic and ecological significance. However, quality deterioration due to salinity causes significant decrease in agricultural productivity and a public health problem. This study focuses on hydro-chemical and microbial quality of water sources in Kilifi County. Water samples were collected from 25 different locations within Kilifi County and indicators of salinity and microbial load analyzed. Temperature, pH, EC and TDS were determined using portable pH meter. Anions; F-, Br-, Cl-, SO42-, PO43-, NO2-, NO3-, CO32-, HCO3- and NH4+ were determined using Ion Exchange Chromatography. Cations; Na+, K+, Ca2+, Mg2+, Zn2+, Fe2+, Cd2+, Cr3+, Al3+ and Ag+ were determined using flame photometry. Standard methods were used to determine Microbial loads. Results were pH (7.42±0.52), Temperature (24.61±0.21oC), EC (3.44±0.75 dscm-1), TDS (1672.53±122.87 mgL-1) and Turbidity (152.29±41.20 NTU). Anions; F- (2.90±0.24 mg/L), Cl- (1756.68±900.50 mg/L), NO2- (4.47±0.49 mg/L), Br- (11.72±1.20 mg/L), NO3- (4.67±0.38 mg/L), HCO3- (200.54±25.58 mg/L) PO43- (0.94±0.10 mg/L), CO32- (29.94±2.32 mg/L), and SO42- (300.64±42.47 mg/L). Cations; K+ (8751.80±214.04 mgL-1), Na+ (59.43±1.98 mgL-1), Ca2+ (4.00±0.16 mgL-1), Mg2+ (59.43±1.98 mgL-1), Zn2+ (0.76±0.30 mgL-1), Cu2+ (0.18±0.01 mgL-1), Ag+ (0.03±0.01 mg/L), Cd2+ (0.07±0.01 mg/L), Cr3+ (0.35±0.01 mg/L), Al3+ (0.33±0.01 mg/L) and NH4+ (2.01±1.96 mg/L). Microbial load; MPN (20811.00±402.00), Total coliforms (2970.00±60.00 CFU 100 mL-1), E. coli (26.00±3.00 CFU 100mL-1), S. aureus (411.00±12.00 CFU 100mL-1), Shegela (24.00±2.00 CFU 100mL-1) and S. typhi (67.00±2.00 CFU 100mL-1). Temperature, pH, EC, TDS, Turbidity, F-, Cl-, Br-, PO43-, Na+, Zn2+, Fe2+ and microbial load were above WHO limits whereas SO42-, NO2-, NO3-, CO32-, HCO3-, NH4+, K+, Ca2+, Mg2+, Cd2+, Cr3+, Al3+ and Ag+ were below WHO limits. The study concludes that water sources in Kilifi County are unsuitable for domestic and agricultural uses. It’s recommended that a continuous water quality monitoring program be put in place and development of effective management practices for utilization of the surface water resources be instituted.

Temporal assessment of heavy metal concentration and surface water quality representing the public health evaluation from the Meghna River estuary, Bangladesh

The Meghna River, the largest and the widest river in Bangladesh, is important for navigation, irrigation, fish spawning and shelter, industrial usages, and drinking water sources for millions of people living in nearby areas. The present study illustrated the seasonal variation of some physicochemical parameters and the four heavy metals (Cr, As, Cd, and Pb) distribution in the surface water of Meghna River estuary. It also evaluated the human health risk for adult and children due to directly contact with the surface water through ingestion and dermal pathways. The ranges of metal concentration in the study area were found in the descending order as: Cr (0.036–0.054; mean 0.045 ± 0.005) > As (0.012–0.036; mean 0.024 ± 0.007) > Cd (0.009–0.050; mean 0.018 ± 0.012) > Pb (0.007–0.014; mean 0.009 ± 0.007). In most cases, the concentrations of As, Cr, Pb, and Cd surpassed the guideline limits of human consumption. However, the one-way ANOVA study revealed that the average concentrations of the selected metals in the ten sampling sites were not significantly different at a 95% confidence level. Therefore, it is assumed that the metal contamination in the study area might have been caused due to the anthropogenic sources along with the natural phenomenon. The distribution of the metal contents and the physicochemical parameters in the surface water greatly were significantly different concerning both winter and summer seasons at a 95% confidence level. The evaluated hazard quotient (HQ) and the hazard index (HI) for the investigated metal compounds were in the acceptable limit (< 1). In addition, the attribution of metal contents did not overweigh the carcinogenic risk (CR) range (10–6 to 10–4), and the adults are more susceptible than the children. Although the risk is within the acceptable level, but adequate monitoring aspects should be implemented to control surface water pollution especially for the metal discharge to the river estuary.

Water Quality Assessment of Tigris River Using Overall Index of Pollution (OIP)

This study was performed on the Tigris River (Baghdad city section) during the period between December 2016 and December 2018 to assess seasonal variation in water quality using the Overall Index of Pollution (OIP). The OIP is one of the reliable tools for the assessment of surface water quality. To calculate OIP-values, eight parameters were measured ( pH, Dissolved Oxygen "DO", Biological Oxygen Demand "BOD", Total Dissolved Solid "TDS", Total Hardness "TH", calcium "Ca", Sulphate "SO4" and Alkalinity). The results showed the anthropogenic activities impact of Baghdad population that directly discharge of "inadequate treated" waste water to the river. OIP values were acceptable (1˃OIP˃ 1.7) in 2011, 2012, 2013 and 2018. However, in 2014 and 2017,the OIP recorded values that were acceptable and tend to be slightly polluted (1.7˃OIP˃2.5). The impairment of water quality during 2014 and 2017 might be caused by the decrease in the water share feeding Tigris River from Turkey due to the construction of many dams. Also, markedly reduced rain precipitation rates were recorded in these periods. The study suggests conducting continuous monitoring programs and establishing a reliable Iraqi classification system for water quality by a specialized scientific panel.

Health Risk and Water Quality Assessment of Surface Water in an Urban River of Bangladesh

Despite significant contributions to the national economy of Bangladesh, various urban developments, massive industrial and growing shipping activities are making the water of many urban rivers, including Karnaphuli River, extremely polluted. To find out the pollution sources and their possible health effects, 45 water samples were collected from 15 sampling stations. Investigation of six physicochemical parameters (pH, temperature, total dissolved solids, conductivity, salinity, and turbidity) through in-situ measurements and eight heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) status using atomic absorption spectrophotometer (AAS) was carried out in this research. Both the physicochemical parameters and heavy metals exceeded the World Health Organization (WHO)’s permeable threshold limit. The calculated hazard quotient (HQ) and hazard index (HI) ingestion values indicate non-carcinogenic risk both for adults and children, but dermal exposure was within the safety limit. Carcinogenic risk analysis revealed that Cd could cause a risk of cancer in those using the river water for a long period. Spatial analysis and metal pollution index (MPI) results exhibit that downstream of the river water is more polluted than upstream of the river. Overall, the findings of this study imply that polluted water is a threat to human health and the results will also help to undertake proper management strategies and incorporate monitoring programs that study river water for the implementation of safety measures to protect human health.

Spatial and temporal assessment of surface water quality using water quality index. The Saguling Reservoir, Indonesia

Developments in agriculture, industry, and urban life have caused the deterioration of water resources, such as rivers and reservoirs in terms of their quality and quantity. This includes the Saguling Reservoir located in the Citarum Basin, Indonesia. A review of previous studies reveals that the water quality index ( WQI) is efficient for the identification of pollution sources, as well as for the understanding of temporal and spatial variations in reservoir water quality. The NSFWQI (The National Sanitation Foundation water quality index) is one of WQI calculation methods. The NSFWQI is commonly used as an indi-cator of surface water quality. It is based on nitrate, phosphate, turbidity, temperature, faecal coliform, pH, DO, TDS, and BOD. The average NSFWQI has been 48.42 during a dry year, 43.97 during a normal year, and 45.82 during a wet year. The WQI helped to classify water quality in the Saguling Reservoir as “bad”. This study reveals that the strongest and most significant correlation between the parameter concentration and the WQI is the turbidity concentration, for which the coeffi-cient correlation is 0.821 in a dry year, and faecal coli, for which the coefficient correlation is 0.729 in a dry year. Both parameters can be used to calculate the WQI. The research also included a nitrate concentration distribution analysis around the Saguling Reservoir using the Inverse Distance Weighted method.

Surface Water Quality and Health Risk Assessment in Taizhou City, Zhejiang Province (China)

Surface Water Quality and Health Risk Assessment in Taizhou City, Zhejiang Province (China)