Applied Water Science (v.9, #1)

This study was an attempt to understand the factors influencing the heavy metal distribution in polluted fluvial system sediments. Various biogeochemical processes and anthropogenic factors were playing an important role in altering the concentration of heavy metals in the sediments. This paper has two objectives: The first one is to investigate the effect of the variation in the physicochemical conditions on the speciation of trace elements trapped in the sediments of the Sebou River. The second one is to study the kinetics mobilization of these heavy metals. Batch resuspension experiments were conducted in order to investigate the release of heavy metals from a polluted anoxic sediment submitted to different physicochemical conditions variations. It has been revealed that in oxygenated environment, sediments were oxidized which cause the release of some heavy metals, but their concentrations, as dissolved phase, were sustained constant or were increased with time. However, in acidic and anaerobic environment, most of the metallic trace elements were released together with the iron and the manganese, but some of these elements like chromium were precipitated. However, some of other elements were maintained in solution, which represents a real human health risk.
Keywords: Sediment; Heavy metals release; Resuspension; Speciation; Physicochemical conditions

The purpose of this study is to predict the hydrological responses to climate change in the upstream catchment of Kase River basin having an area of 225 km2 by using MIKE SHE model and GIS. Meteorological and hydrological data for the period of 5 years were available in Kase River basin. Average daily discharge data from 5-year period (1991–1995) were used for the calibration effort, and average daily discharge was measured at Kawakami station. The Nash–Sutcliffe efficiency, NSE = 0.588, suggests that the model can predict the runoff mechanism for different periods satisfactorily. To assess the climate change impacts, two scenarios were taken under consideration. The data generated from RCM 20 (Regional Climate Model) were utilized under scenario 1 to predict future period 2081–2100 in the river basin. On the other hand, CC-scenario 2 assumes an increase in average monthly air temperature about 3 °C and no change in precipitation in future at the end of twenty-first century. The results revealed that future climate variability under scenario 1 caused an increase of 408.16 mm in surface flow; 46.77 mm in terms of base flow and interflow; and an increase of 41.74 mm actual ET (evapotranspiration). The increase in surface runoff may be mostly due to increase in precipitation. Future climate variability under scenario 2 caused a decrease of 38.43 mm in surface flow; 2.25 mm in terms of base flow and interflow; and an increase of 46.62 mm actual ET. The decrease in surface runoff may be due to unchanged precipitation and increase in temperature.
Keywords: GIS; MIKE SHE; Hydrological processes; Discharge; Climate change scenarios

Seaweed Sargassum wightii is one of the most important marine resources as they have biological activity. Numerous researchers have reported on brilliant green dye decolourization using various seaweed. Despite its impact on after treatment, little information is available on the effect of seaweed-treated dye toxicity against plants and microorganisms. The present investigation was carried out to assess the microbial toxicity of S. wightii-treated and untreated dye using various microorganisms and cytotoxicity effect on Allium cepa L. In this study, untreated dye which has substantial amount of the colour in it exhibited significant toxic effect against major gram-positive and gram-negative bacteria. The clear zone of inhibition exhibited by the untreated dye around bacterial and fungal colonies reflects its extent of microbial toxicity and infers that the untreated dye has antibacterial and antifungal activity. No inhibition zones were observed with treated dye when compared with the untreated dye. Consequently, treated dye does not exhibit microbial toxicity due to the complete absence of the dye in it. Cytotoxicity study on A. cepa grown in untreated dye solution showed decrease in root growth, increase in the mitotic index and chromosomal damage, whereas A. cepa bulbs grown in seaweed-treated dye showed betterment in root growth, increase in the mitotic index and decrease in chromosomal damage. Results of the cytotoxicity study indicated the untreated dye solution exerts toxic effect on A. cepa, whereas treated dye solution did not pose any toxic effect. This indirectly proves the efficiency of marine algae in complete removal of the dye from the present study. Thus, worldwide awareness of dye removal from aqueous solution and its management could be provoked.
Keywords: Seaweed; Brilliant green dye; Microbial toxicity; Cytotoxicity

Modelling of the impact of water quality on the infiltration rate of the soil by Balraj Singh; Parveen Sihag; Surinder Deswal (1-9).
The concept behind of this paper is to check the potential of the three regression-based techniques, i.e. M5P tree, support vector machine (SVM) and Gaussian process (GP), to estimate the infiltration rate of the soil and to compare with two empirical models, i.e. Kostiakov model and multi-linear regression (MLR). Totally, 132 observations were obtained from the laboratory experiments, out of which 92 observations were used for training and residual 40 for testing the models. A double-ring infiltrometer was used for experimentation with different concentrations (1%, 5%, 10% and 15%) of impurities and different types of water quality (ash and organic manure). Cumulative time (T f), type of impurities (I t), concentration of impurities (C i) and moisture content (W c) were the input variables, whereas infiltration rate was considered as target. For SVM and GP regression, two kernel functions (radial based kernel and Pearson VII kernel function) were used. The results from this investigation suggest that M5P tree technique is more precise as compared to the GP, SVR, MLR approach and Kostiakov model. Among GP, SVR, MLR approach and Kostiakov model, MLR is more accurate for estimating the infiltration rate of the soil. Thus, M5P tree is a technique which could be used for modelling the infiltration rate for the given data set. Sensitivity analyses suggest that the cumulative time (T f) is the major influencing parameter on which infiltration rate of the soil depends.
Keywords: Double-ring infiltrometer; Gaussian process; Support vector regression; M5P tree model

Water quality assessment is essential to ensure viable safe use of the resources for drinking, agricultural and industrial purposes. Deterioration of groundwater quality due to anthropogenic activities is increasing at an alarming rate in most parts of Dindigul district, but limited work has been carried out on groundwater quality and monitoring. This paper highlights the groundwater quality and compares its suitability for drinking and irrigation purpose of Batlagundu block in Dindigul district of Tamil Nadu. Eighteen groundwater samples were collected systematically in triplicates during the year 2013–2014. The physical and chemical parameters of the analytical results of groundwater were compared with the standard guideline values recommended by the Bureau of Indian Standards and World Health Organization for irrigational suitability, domestic usage. Further hydrogeochemical data have been plotted in standard graphs such as Piper trilinear diagram, US Salinity Laboratory (USSL), Giggenbach triangle diagram and Schoeller diagram. The mathematical models are used to estimate water quality parameters and to describe realistic water situations. It is proved that electrical conductance is an important water quality parameter. Hydrofacies diagram reported that alkaline earths (Ca2+ and Mg2+) significantly exceed the alkalis (Na+ and K+), while acids of (Cl and HCO3 ) exceed the acids of (SO4 2− and CO3 2−). Therefore, the chemical compositions of the study area were characterized by the Ca–Mg–HCO3 water type and Na–Cl type. USSL diagram of the study area revealed that most of the sampling sites possess high salinity and low-to-medium sodium hazard indicated that water samples are poorly suitable for usual agropurposes. Giggenbach triangular diagram indicated that the samples have not gained equilibrium with their host rocks, presumably due to fact circulation of fluid through the rock features. The present research work thus concludes that groundwater in the study area is chemically unsuitable for domestic and agricultural uses. It is recommended to carry out a continuous water quality monitoring program and development of effective management practices for utilization of water resources.
Keywords: Piper; USSL; Giggenbach; Schoeller; Groundwater; Batlagundu

A study was undertaken from January to June 2016 with the aim of characterizing the environmental forms of intestinal helminths that are present in some marshy areas in Yaounde. Monthly water samplings were carried out on eight different marshy areas which are: Bonamoussadi, Melen, Etoug-ebe, Mvog-betsi, Mokolo-elobie, Tsinga, Ekounou and Damas in the city of Yaounde. The observation of eggs and larvae of helminths was done using an inverted Olympus CK2 microscope with objective 40, after concentration of the samples, following the formol-ether concentration and/or Kato–Katz techniques. The hydrological and physicochemical assessment of the samples reveals a low oxygenation (20.93 ± 9.83%) and a high mineralization (566.16 ± 119.91 μS/cm) of these ecosystems. The biological analysis reveals the presence of eggs belonging to Ascaris sp., Enterobius sp., Ankylostomes sp., Trichostrongylus sp., Trichuris sp., Tænia sp., Hymenolepis nana, Hymenolepis diminuta, Diphyllobothrium sp., Fasciola sp., Schistosoma sp. and the larvae of Strongyloïdes sp. The statistical analysis presents a significant correlations to the threshold of 5% and 1% between the physicochemical and biological parameters quantified in our study.
Keywords: Abundance dynamics; Helminths resistance forms; Marshy areas

There are some sources of pollution of the groundwater such as the industrial, agriculture, domestic activities and the oxidation ponds that are considered collection points for waste disposal plants. The motivations to do this work were: (1) investigating the concentrations of pollutants in the oxidation ponds and well surrounding the 10th Ramadan city and (2) predicting the groundwater flow and the pollutant transport to the groundwater from the pollution source using a numerical simulation (MODFLOW-2000 with MT3D code). The samples of groundwater were collected from the wells that spread around the studied area as well as many samples were collected from the oxidation ponds to investigate the concentrations of pollutants in these samples and predict the pollutant transport to the groundwater over 30 years. The results illustrated that the ion concentration of most samples from the oxidation ponds resources contained Al3+, Fe2+, Sr2+, Ni2+, and Cr2+ which were exceeding the acceptable limit of WHO (International standards for drinking water, WHO, Geneva, 1996) standards. The results also demonstrated that most of the analyzed groundwater samples are polluted with strontium (Sr2+), aluminum (Al3+), and iron (Fe2+). The simulation predicted that the pollutants movements toward the northeast of the study zone over a long-term period (30 years).
Keywords: Groundwater; Pollution; Pollutants; MODFLOW; Agricultural; Domestic; Industrial activities; Heavy metals; Oxidation ponds; 10th of Ramadan city

Geo-spatial technique-based approach on drainage morphometric analysis at Kalrayan Hills, Tamil Nadu, India by R. Sakthivel; N. Jawahar Raj; V. Sivasankar; P. Akhila; Kiyoshi Omine (1-18).
Drainages are pulses which in turn help us to understand the ongoing process in the hill ecosystem. The Kalrayan hill is known for its dissected terrain condition, rich biological diversity and depletion of natural resources. Therefore, a study on quantitative geomorphometry was carried out in the Kalrayan Hills, Eastern Ghats, Tamil Nadu, using Indian remote sensing 1D LISSIII satellite data. The study area was divided into 36 watersheds and total area is 1158.4 km2. It covers the upper part of Vellar basin. The linear, aerial and relief aspects and different morphometric parameters such as stream length, bifurcation ratio, drainage density, stream frequency, drainage texture, relief ratio, basin shape, form factor, circularity ratio, elongation ratio and length of overland flow were computed using standard methods, formulae and geo-spatial technologies. Based on the present drainage morphometric study, it is inferred that the watersheds 3, 4, 6, 9, 11, 12, 15, 17, 18, 19, 20, 22, 24, 27, 32, 33, 34 and 36 are active with reference to geological processes, mean denudational rate, peak discharge, mean annual run off, dominant watershed process and sediment yield per unit area. Multi-criteria analysis is performed to determine the drainage architecture and hydrogeological processes occurring in the present hill area.
Keywords: Basin hydrology; Morphometric parameters; Water resource management; Kalrayan hills; Multi-criteria analysis

The present research studied the antibacterial effect of silver-coated Ni0.5Zn0.5Fe2O4 magnetic nanoparticles on Gram-negative bacteria Escherichia coli (E. coli) from water. The effects of pH (6, 7 and 9), disinfectant dose (2, 5 and 10 g/L) and contact time (10, 20 and 30 min) have been also investigated. To obtain important factors, the interactions between factors and optimal experimental design in surface response method were used based on Box–Behnken design. According to the research findings, the system is efficient in eliminating E. coli. The results showed that E. coli elimination efficiency intensified through increasing the amount of nanoparticles from 2 to 10 g/L. The results also demonstrated no significant change in E. coli elimination through pH increasing of 6 to 9. Expanding contact time from 10 to 30 min also heightened E. coli elimination rate. R 2 for E. coli elimination is 0.9994 indicating a good agreement between model experimental data and forecasting data.
Keywords: Magnetic nanoparticles; Escherichia coli ; Silver nanoparticles; Box–Behnken design

The hydrogeochemical characteristics, water quality and health risk statuses of waters in Umunya district, southeastern Nigeria were studied, in attempt to evaluate their suitability for drinking and domestic purposes. Twelve groundwater and 3 surface water samples were analyzed for 26 physicochemical and hydrogeochemical parameters, using standard techniques. Results show that dominance of cations and anions is in the order Ca2+ > Na+ > K+ > Mg2+ and HCO3  > Cl > NO3  > SO4 , respectively. Order of dominance of the heavy metals is Pb > Zn > Fe > Ni > Mn > Cr > Ba. Eight water types were identified, with Ca–Na–HCO3 (26.66%) and Na–Cl–HCO3 (20%) dominating the study area. All the water types characterize five major facies. Further, the result revealed that the physical properties and chemical ionic concentrations in the waters are well below standard maximum permissible limits, although majority of the samples have pH values off the allowable limits of 6.5–8.5, classing the waters as slightly acidic. Generally, the water quality in the study area is deteriorated due to the presence of high levels of heavy metals. Water quality index results show that 46.67% of the water samples are in excellent and good categories. 13.33% are in poor water category, whereas 40% are in category unsuitable for drinking purposes. A good percentage of the waters predispose users to health risks. Stoichiometric and statistical analyses revealed that the variations in chemistry and quality of the waters are due to combined influence of human activities and geogenic processes (silicate weathering and ionic exchanges). Treatment of contaminated waters before use is, therefore, recommended.
Keywords: Hydrogeochemistry; Water contamination; Water quality index (WQI); Water resources; Umunya

In this study, four surface water quality datasets of upper Damodar river basin (DRB) covering three seasons; pre-monsoon, monsoon, post-monsoon and annual, for years 2007–2010 were generated by analyzing 280 grab water samples. Each dataset consist of water quality constituents of 35 monitoring stations and sample of each station was evaluated by 17 critical parameters (total 4760 observations). Furthermore, each dataset was treated using six water quality indices (WQIs): four developed simplified indices (WQIm, WQImin, WQIDO, and WQIpca) and two existing extended indices (WQIobj and WQIsub), to assess spatiotemporal variations and suitability for human use and aquatic life. Results revealed that developed indices show on an average similar spatiotemporal variations as compared to WQIobj at a lower analytical cost at most of sampling sites comes under good to medium categories of water quality. Geographical information system (GIS) technique was also used for generation of temporal pollution potential maps of DRB. Consequently, this study also presents the necessity and usefulness of developed indices over extended indices especially for the developing countries, because the cost of monitoring and expenses associated with the implementation is less compared to extended methods and generated maps may also facilitate the decision-making processes under various scenarios considering spatial and temporal variability in DRB.
Keywords: Damodar river basin; Water quality index; Geographical information system

The Karmanasa basin is spread over the Kaimur sandstone (Upper Vindhyan) and marginal Ganga plain with the areal extension of about 7926 km2. The quantitative approach of the basin development of the Karmanasa River basin was carried out by the morphometric parameters. The drainage network was extracted from SRTM data. The trellis pattern characterizes upstream of the drainage basin, while the dendritic pattern is noticed in middle and downstream of the basin. The drainage density (0.34–0.44) indicates that the basin has highly permeable subsoil and thick vegetative cover. Relatively larger values of form factor (SW-1, SW-2, SW-3, SW-6 and KW) signify higher flow peak for a shorter duration. High values of ruggedness number and relief ratio suggest that Karmanasa basin is prone to soil erosion. The present work shows that the Karmanasa basin is less prone to flood, vulnerable to soil erosion and a good resource of surface water. This study would help to utilize the water resources and extended for sustainable development of the Karmanasa River basin area.
Keywords: North central India; Karmanasa River basin; Morphometric; Drainage density; Soil erosion

Influence of physicochemical water quality on aquatic macrophyte diversity in seasonal wetlands by S. Rameshkumar; Kalidoss Radhakrishnan; S. Aanand; R. Rajaram (1-8).
The present study aims to assess the physicochemical parameters and distribution of aquatic macrophytes of seasonal wetlands flowing into the coast of Palk Bay, southeast coast of India. We tested the hypothesis whether there is any statistically significant difference in physicochemical parameters and macrophyte communities among study location. Water quality parameters such as temperature, pH, salinity, TDS, DO, turbidity and electrical conductivity, and the aquatic macrophyte diversity were estimated in all three stations. One-way analysis of variance (ANOVA) and Pearson correlation were employed to assess the relationship between water quality parameters, and the water quality index (WQI) was computed to assess the status of water conditions. The ANOVA revealed that there is no statistically significant difference (p > 0.05) in water quality parameters among the three stations. The lowest f value 0.180 was recorded for pH and highest of 2.478 for TDS. A total of 7 submerged macrophytes, namely Ceratophyllum demersum L., Egeria densa Planch., Lemna minor L., Marsilea quadrifolia L., Sagittaria guayanensis and Isoetes riparia; 6 rooted floating weeds, namely Potamogeton nodosus Poir., Nymphaea odorata Aiton., Nelumbo nucifera Gaertn., Myriophyllum spicatum L. and Hydrilla verticillata; 1 floating, namely Eichhornia crassipes Kunth; and 1 rooted macrophyte, namely Najas minor, were recorded in Tharavai wetland. A deplorable water quality condition was found in the selected study area, which was evidenced from WQI (> 76%). Of this, submerged aquatic vegetation is used as the water quality key indicator, and it exists where there is a better water quality condition. The EC, TDS and turbidity negatively influenced the aquatic macrophytes. Therefore, there is a need for some adaptation measure to maintain the water quality for more extended period for domestic use.
Keywords: Seasonal wetland; Physicochemical parameters; Water quality index; Macrophytes; Wetland ecosystem

Flood risk and adaptation in Indian coastal cities: recent scenarios by Ravinder Dhiman; Renjith VishnuRadhan; T. I. Eldho; Arun Inamdar (1-16).
Coastal cities contrive to spread their transformative influence both into the hinterland, along the coastline, and into the coastal waters themselves. These effects will be intensified in urban agglomerations as the concentration of population and allied activities are more pronounced there compared to the inland regions. Indian coastal cities are no exception, and it is high time to delineate these hazard-prone regions and implement proper mitigation and adaptation strategies at city scale. This review article provides an assessment regarding quantification, management and climate change impacts of flood risks in Surat, Mumbai, Chennai and Kolkata, which are the most populated coastal cities in India. The flood impacts considered in the existing or prevailing analyses are associated with adverse effects on population, land use of cities, transportation and economy caused by different types of riverine and urban flooding, though coastal flooding, tsunami and storm surge effects are less studied. Mumbai and Kolkata are relatively progressive in the assessment of flood risks and adaptation. The present article also suggests strategies to evaluate the relative progress in the assessment of past and future risks and adaptation. We also discuss the mitigation and adaptation strategies considering the historical importance of these cities. We propose that the strategies should be implemented considering public opinion and should be initialized at the grass root level. Though it is technically difficult to re-plan the city structures in the current scenario, it is possible to adapt to and mitigate the effects of natural hazards through suitable planning and management with the integrated cooperation and involvement of citizens and government as well.
Keywords: Flood management; Urban planning; Coastal megacities; Adaptation; Risks

In basin of the Great Sebkha of Oran, water deficit linked to climate semi-aridity has forced farmers to resort to the use of underground water of poor quality, which considered as the major cause of soil degradation. The alluvial aquifer waters are particularly characterized by higher relatively concentration in dissolved salts when compared them with other aquifers of the same system. Generally, the salinity of the water increases from upstream to downstream in the direction of the Sebkha (Boualla et al. in Water Supply 17(6):1801–1812, 2017). Assessment of soil quality has become the basic work for agricultural sustainable development. The aim of this paper is to evaluate soil properties in great Sebkha of Oran basin. Geo-referred soil samples were collected from ten-component analysis, and different soils were analysed for different physical and chemical attributes. Our study focuses on mineralogical analysis and geochemical prospecting using soil chemical data. Eleven indicators were selected to constitute data to assess the soil quality: sieve analysis, classification, cation exchange capacity, pH, soil organic matter, conductivity, gypsum, nature of the oxide content, nutrients (NO3-N, NH4-N, PO4-P), anions content (SO4 2−, Cl) and mineralogical analysis. Conclusively, process and mechanism of soil quality need deep research.
Keywords: Soil; Quality; Cation exchange capacity; Organic matter; Oxides; Leaching fraction

In this paper, the economics analysis of water production by using different solid desiccant materials and composite materials through Scheffler reflector is presented. The experiments for water production have been performed at National Institute of Technology, Kurukshetra, Haryana, India [29°58′ (latitude) North and 76°53′ (longitude) East]. The various factors have been carried out to calculate the annual cost/liter in Indian currency. Total six cases are studied, and for each case, uniform procedure is adopted. The silica gel gives the best economical annual cost/liter compared to molecular sieve and activated alumina in case of solid desiccant, and for composite material, it is CaCl2/River Sand compared to LiCl/River Sand and LiBr/River sand.
Keywords: Economic analysis; Water production; Scheffler reflector; Desiccant material

The present study was carried out to evaluate the performance of 16.1 MLD sewage treatment plant (STP) located at Brari Nambal (J&K), India. The STP is based on sequential batch reactor (SBR) technology. Wastewater (influent and effluent) samples were analyzed for 14 different physicochemical parameters. Significant variation (P < 0.05) was recorded within and among the wastewaters in pH (F 11,1 = 7.49, 26), electrical conductivity (F 11,1 = 12.13, 49.94), calcium (F 11,1 = 8.58, 91.66), magnesium (F 11,1 = 4.68, 132.37), chloride (F 11,1 = 10.18, 74.85), sodium (F 11,1 = 11.31, 192.64), potassium (F 11,1 = 5.98, 52.22) and chemical oxygen demand (F 11,1 = 4.16, 267.65), whereas among the wastewaters in total suspended solids (F 1 = 165.21), total dissolved solids (F 1 = 150.40), biological oxygen demand (F 1 = 307.89), ortho-phosphate (F 1 = 624.54), total phosphorous (F 1 = 336.85) and nitrate nitrogen (F 1 = 68.10). Significant negative correlation exists between TSS and EC (r = − 0.796; P < 0.01) and Cl and Ca (r = − 0.646; P < 0.05), whereas significant positive correlation between BOD5 and Ca (r = 0.579; P < 0.05), COD and TSS (r = 0.728; P < 0.01) and ortho-phosphate and pH (r = 0.791; P < 0.01). Maximum decrease was recorded in TP (68.37%) followed by NO3-N (64.88%), COD (63.79%), BOD (59.38%), OP (55.94%), TDS (44.82%) and least in TSS (38%) among parameters which are of prime concern. Six principal components (PCs) have been identified by factor analysis which explained 90.30% of total variance, representing alkaline factor, salts/ions factor, household/water usage factor, dissolved salts factor, soaps/detergents factor and catchment factor. Thus, least reduction in concentration of ortho-phosphate, TDS and TSS is concern when the effluent is disposed off in a water body which is already under the stress of nutrient enrichment/pollution.
Keywords: Effluent; Influent; Sequential batch reactor; Sewage treatment plant

Identification of homogeneous precipitation regions via Fuzzy c-means in the hydrographic region of Tocantins–Araguaia of Brazilian Amazonia by Evanice Pinheiro Gomes; Claudio José Cavalcante Blanco; Francisco Carlos Lira Pessoa (1-12).
Determination of homogeneous regions of precipitation is a major step towards obtaining regional rainfall patterns, which are models for the estimation of total rainfall used in water resources engineering. In this study, homogeneous regions of precipitation were identified within the Hydrographic Region of Tocantins–Araguaia (HRTA) of Brazilian Amazonia. This hydrographic basin is of great importance for Brazil because it has been exploited for the production of hydropower since the 1970s. Currently it is a border of the agribusiness of the country. Therefore, it is important to know the rainfall regime of the region. Thus, three homogeneous regions of precipitation were delimited using the Fuzzy c-means method and physical-climatic variables such as location (latitude and longitude), altitude, and precipitation. These regions were also tested and confirmed for their homogeneity using the Heterogeneity Test H. The values of total precipitation found for the regions are consistent with the volume of precipitation recorded in the analysed region and that found in the literature. The formation of these regions, in addition to contributing to the understanding of the hydrological behaviour, will aid in studies of the regionalization of rainfall in the region.
Keywords: Physical-climatic variables; PBM index; Heterogeneity Test H

A novel approach for the removal of lead (II) ion from wastewater using Kaolinite/Smectite natural composite adsorbent by I. M. El-Naggar; Sayed A. Ahmed; Nabila Shehata; E. S. Sheneshen; Mahmoud Fathy; Amr Shehata (1-13).
Lead is one of the fundamentally risky metal ions existing in wastewater. A laboratory batch technique carried out to study the impact of initial concentration, pH, temperature, a dose of adsorbent and contact time on the elimination of lead ions onto oil shell sedimentary rock as natural clay. Two natural inorganic composites Kaolinite/Smectite-A and Kaolinite/Smectite-B have been used. The lead removal enlarged with rising initial metal solution concentration, contact time and pH. The elimination reaction speed was high at the initial period of contact time and then decreased to attain equilibrium at 45, 30 min for Kaolinite/Smectite-A and Kaolinite/Smectite-B adsorbents, respectively. Mutually, Langmuir and Freundlich’s isotherms are applicable to describe the metals adsorption and thermodynamic parameters ΔG; ΔS and ΔH were calculated indicating that the adsorption process is physisorption, spur-of-the-moment and endothermic.
Keywords: Heavy toxic element; Natural adsorbent; Waste; Lead; Removal; Adsorption

Rivers, a major freshwater resource, are transboundary in nature (310 international basins) and are not governed by any water agreements. Scientific knowledge based on transboundary water resources is confined; hence, the identification of “knowledge gaps” to smoothen decision making in water management is necessary. To figure out the issues that affect water sharing is deemed important. This paper highlights the core issues involved in transboundary water management and prioritizes the identified issues using fuzzy c-means clustering algorithm. A group of 30 experts from various fields were consulted to rank the issues which were clustered to determine the prioritized rank. In a hypothetical basin affected by all the transboundary issues, flood control and benefit sharing are rated with very high importance. Prioritization would help in the identification of issues of high relevance that affect water sharing. This may facilitate efficient water sharing agreements among riparians and be useful in international water governance.
Keywords: Transboundary water resources; Water management; Fuzzy c-means clustering; Cluster center; Prioritization; Riparians

Assessment of physicochemical and bacteriological parameters in surface water of Padma River, Bangladesh by Md. Ayenuddin Haque; Md. Abu Sayed Jewel; Mst. Papia Sultana (1-8).
In the present study, surface water samples were collected during three seasons (summer, monsoon and winter) from four different study sites (T-dam, Padma Garden, I-dam and Talaimari point) of Padma River at Rajshahi, Bangladesh, and various physicochemical and bacterial parameters were analyzed based on standard methods. Significant differences (p < 0.05) in physicochemical parameters were observed among the seasons and sites except for water temperature. However, except for fecal coliform, other bacterial parameters such as total heterotrophic bacteria, total coliform and Vibrio cholerae counts showed significant differences (p < 0.05) among the seasons, while difference among the sites was insignificant (p < 0.05). The result also showed that all the bacterial parameters were maximum during summer and minimum during monsoon season. Untreated sewage and industrial effluents together with reduced water flow and water level were found to increase bacterial counts during summer at Site 2 (Padma Garden). Although the present situation is not serious and alarming enough, the river water requires intensive monitoring to improve its quality for better and sustainable management.
Keywords: Physicochemical parameters; Coliform bacteria; Vibrio cholerae ; Padma River

While there are different methods and models that can be applied to estimate the qualitative and quantitative parameters of water resources, unfortunately, no comprehensive qualitative and quantitative data exist about water resources in Iran. The present study is to compare the performance of the artificial neural network (ANN) and the multivariate regression methods in simulating spring discharge in the Caspian Southern Watersheds. Multivariate regression method was used by using SPSS software. Springs average discharge was considered as the dependent variable and other affecting factors as independent variables. Two linear models were presented for estimating the alluvial and karst springs discharge. Then, the models’ performance was evaluated and confirmed. Also, the artificial neural network was applied to simulate the alluvial and karst springs discharge. ANN performance was evaluated through two parameters: median root of square of the error and Pearson’s R-squared statistics. The results showed that the most important factors of karst springs discharge were the porosity of aquifer formation and the site elevation; in case of the alluvial springs, the transmissivity of aquifer formation and the aquifer depth were the most important factors. Moreover, ANN efficiency in estimating springs discharge was higher than that of the multivariate regression method.
Keywords: Porosity; Water table; Alluvial and karst springs; Simulation

Vertical hydraulic conductivity of riverbank and hyporheic zone sediment at Muda River riverbank filtration site, Malaysia by Mohd Khairul Nizar Shamsuddin; Wan Nor Azmin Sulaiman; Mohammad Firuz Ramli; Faradiella Mohd Kusin (1-22).
In analysing the stream–aquifer interactions and riverbank filtration (RBF) systems, it is very crucial to determine the vertical riverbank and streambed hydraulic conductivity. The riverbank and streambed focused in this investigation are a riverbank of six layers with depths of 38 m and streambed with depths of 9 m connected layers of sediments at 22 test locations and 4 test wells in the Muda River, Malaysia. In the analysis, there were a few tests involved to determine riverbank and hydraulic conductivity of vertical streambed, such as analysis of grain size, pumping test and in situ falling head standpipe permeability tests. The approximate K values of 114 samples and 15 samples taken from riverbanks and streambeds, respectively, were then calculated by employing empirical equation methods [Hazen, Hazen K (cm/s) = d10 (mm), Terzaghi, Beyer, Slichter, Sauerbrei, Kruger, Kozeny–Carman, Zunker, USBR, Zamarin, Barr, Alyamani and Sen, Chapuis, and Krumbein and Monk]. The geometric mean of K for six layers, namely the sandy silt (8.30 m/day), silty sand (47.66 m/day), gravelly sand (150.24 m/day), sandy gravel layer (418.48 m/day), gravelly sand (151.09 m/day) and silty clay (9.36 m/day) as identified characteristics by using grain-size analyses, was greater than the K of pumping test (geometric mean) (31.10 m/day) and the mean obtained from K of permeability tests (7.03 m/day). In general, the K values of upper layer of sediments of streambed were recorded to be larger in comparison with their respective lower layer of sediments. The K value for the upper layer of sediments from all tests located at the left, right and middle parts of the river ranged from 7.56 to 54.77 m/day for upper layer, from 39.80 to 128.40 m/day for middle layer and from 9.11 to 49.92 m/day for lower layer, as described by the grain-size analysis. The value of K ranges based on permeability test indicated that the value of K was from 0.036 to 1.09 m/day for the upper layer and 0.16 to 0.68 m/day for the lower layer of hyporheic sediments zone. Based on the acquired results, the conclusion that the aquifer of the focused area shows possibility for RBF and has the potential to improve the water quality and quantity is referable.
Keywords: Grain-size analysis; Streambed; Riverbank; Hydraulic conductivity; Riverbank filtration; Malaysia

The equilibrium sorption of a local Ayous (Triplochiton scleroxylon) wood sawdust was examined as substitute adsorbent for removal of paraquat from water. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (DRK) isotherms were used to compare the equilibrium sorption data obtained. The separation factor revealed a constructive sorption experiment since the maximum monolayer coverage (Q 0) from Langmuir isotherm model was found out to be 41.66 µmol/g. In addition, the correlation value of Langmuir isotherm model was the maximum among the four adsorption isotherms. From Freundlich isotherm model, the sorption intensity (n) that denotes favorable sorption and the correlation value are 2.402 and 0.929, respectively. Temkin isotherm model was used to calculate the heat of sorption process which corresponds to 18.39 J/mol, and the mean free energy was estimated from DRK isotherm model to be 0.091 kJ/mol which vividly proved that the adsorption experiment was obeyed to a physical process. The results indicate that this local wood sawdust could be employed as an economical material for reducing paraquat from industrial wastewater.
Keywords: Isotherms; Paraquat; Adsorption; Free energy