Collected Water Samples Research Articles

An Assessment of Irrigation Water Quality with Respect to the Reuse of Treated Wastewater in Al-Ahsa Oasis, Saudi Arabia

Irrigation water quality is important to sustain agricultural productivity. The primary irrigation water sources in Al-Ahsa Oasis, KSA, are groundwater wells, mixed with treated wastewater and agricultural drainage. This study sought to evaluate irrigation water quality in Al-Ahsa Oasis with the aid of using irrigation water quality indices (IWQIs). One hundred and forty-eight different water samples were collected from various irrigation water resources throughout Al-Ahsa Oasis. The investigated physiochemical characteristics include pH, temperature, TDS, EC, turbidity, free chlorine, total hardness, cations (Na, K, Ca, Mg), anions (Cl, CO3, HCO3, SO4), organic matter indices (DO, BOD, COD), and nutrients (NH4, NO3, PO4). The IWQIs used in this study include salinity hazard, sodium adsorption ratio (SAR), Kelly’s ratio (KR), soluble sodium percentage (SSP), Permeability index (PI), residual sodium carbonate (RSC), and magnesium hazard (MH). The results indicated that treated wastewater mixed with groundwater is acceptable for irrigation. Spatial variations in irrigation water quality throughout Al-Ahsa are associated with water resources. For instance, groundwater mixed with agricultural drainage has the highest values of TDS, cations, and anions, whereas the lowest values were reported for treated wastewater, reflecting the good efficiency of wastewater treatment plants. The IWQI results revealed that 4.1% and 62.1% of the investigated irrigation water samples were considered good (class III) and satisfactory (class IV) for irrigation, respectively, whereas 33.8% of the collected water samples fall within the severe irrigation restrictions. Moreover, 79.7% of the investigated water samples were classified to have high to very high salinity hazards (C3, C4) and medium to high sodium hazards (S2, S3). Regular monitoring and assessment of treated water quality and wastewater treatment plant efficiency are important factors in achieving the sustainability of treated wastewater reuse in irrigation and consequently food security.

Microplastics in water, sediments and macroinvertebrates in a small river of NW Spain

Microplastics (MPs; plastic particles < 5 mm in size) are very common nowadays and ubiquitous in the environment and can cause harm to aquatic organisms. Around 300 million metric tonnes of plastic are manufactured each year and they are regularly mismanaged. Therefore, MPs are frequently found in the environment. Anthropogenic activity in urban areas is considered one of the major sources of MPs. In view of this, we hypothesized, that MPs are present in all areas of rivers, even in riverheads. We analyzed macroinvertebrates in an urban river for MPs and discuss their potential environmental impact. We collected water samples from the centre of the river and filtered the water. Additionally, we collected sediment samples from the the bottom (S1 and S2, both samples collected specifically for sediments analysis) and from the benthic sediment (S3, sample collected for macroinvertebrates identification) from which macroinvertebrates were sampled for MP analysis and for taxonomic identification in order to estimate the water quality of the river, following the protocol for calculating the IBMWP (MAGRAMA, 2011). Sampling took place in the Gafos River (NW Spain) during summer 2020 at three different sampling sites at the head of the river called upstream (G1), in the middle part of the river and upstream of a town (G2) and in the downstream area before the river mouth in the Atlantic Ocean (G3). Different microplastic fibres and particles were found in all water samples (G1, G2 and G3) and in some of the sediment samples. Analysis of the different types of microplastics was carried out by Fourier-transform infrared spectroscopy in attenuated total reflectance mode (ATR- FTIR). The majority of microplastics in water, sediment and biota consisted of polyvinyl chloride (PVC) and polyethylene terephthalate (PET) and the abundances of MPs were very similar. We found more MP particles in biota and water (35 pieces in each compartment) than in sediments (28). Microplastics were found in the cases of Trichoptera families like Lepidostomatidae and Limnephilidae, and inside the body of some Odonata families such as Gomphidae. This confirms the presence of MPs in aquatic organisms and in habitats of an urban river in Spain. Since MPs have been found in freshwater habitats globally, future studies should analyse which macroinvertebrates could be used as MP bioindicators.

Simulation-driven engineering for the management of harmful algal and cyanobacterial blooms

Harmful algal and cyanobacterial blooms (HABs), occurring in inland and maritime waters, pose threats to natural environments by producing toxins that affect human and animal health. In the past, HABs have been assessed mainly by the manual collection and subsequent analysis of water samples and occasionally by automatic instruments that acquire information from fixed locations. These procedures do not provide data with the desirable spatial and temporal resolution to anticipate the formation of HABs. Hence, new tools and technologies are needed to efficiently detect, characterize and respond to HABs that threaten water quality. It is essential nowadays when the world’s water supply is under tremendous pressure because of climate change, overexploitation, and pollution. This paper introduces Discrete Event System Specification-BLOOM, a novel framework for real-time monitoring and management of HABs. Its purpose is to support high-performance hazard detection with model-based system engineering and cyber-physical systems infrastructure for dynamic environments.

A Case Study on Bacteriological and Physiochemical Evaluation of Hospitals Drinking Water in Pakistan

Background: Seventy percent of the Earth is covered by water, out of which only 1% is fresh water. This fresh water can be used for drinking and other domestic uses. However, a drastic increase in the industrial revolution resulted in depletion of the reservoirs and contamination of the potable fresh water. Around 3.4 M deaths per annum occur as a result of waterborne diseases. Objectives: Therefore, the aim of this study is to establish physical, chemical, and biological parameters for evaluating contamination in the drinking water of hospitals in the Bannu and Kohat divisions, Khyber Pakhtunkhwa, Pakistan. Method: Eleven different hospitals were selected for the collection of water samples. Total solids, total dissolved solids, electrical conductivity, and pH were considered significant physical metrics for this study. The essential and heavy metals were also quantified. Furthermore, biological parameters such as Escherichia coli (E. coli) content of drinking water were also studied by using membrane filtration. Results: The results show that E. coli were detected in nine out of the eleven water samples. Moreover, some of the physicochemical parameters were not within guideline limits specified by the World Health and other international organizations. Conclusions: E coli in most of the hospital drinking water was more than the WHO permissible level of the physiochemical parameters. This will have adverse effects on the health of patients which is a serious threat for the population. Therefore, this investigation provides useful information to the government to take special precautions for maintaining the quality of the potable water in government and private hospitals.

Water Quality Assessment in Hong Xeng Channel, Vientiane Capital

In the capital Vientiane, households, communities and factories discharge wastewater into the Hong Xeng canal, which flows into the Thatluang wetland, where it ends up in the Mak Heiw stream and falls into the Mekong River. Water quality assessment is an excellent factor in indicating the existing water condition. Therefore, the aim of this study was to investigate and collect water samples at 3 locations (P1, P2, and P3) to understand the status of water quality, and analyze 12 water samples of the Hong Xeng Canal and also compare the findings with past data by standard. Methods Data was collected and analyzed in the laboratory for two months from 25 August 2008 to 6 October 2008. The results showed that the temperature was 28°C - 31.1°C, Nitrate ion (NO3-) was 3.2 mg/l - 46 mg/l, pH 5.9-6.6, electrical conductivity 87 µS/cm - 283 µS/cm, Total Suspended Solid (TSS) 22 mg/l -78 mg/l and CODMn 5.5 mg/l - 10 ,9mg/l. Therefore, these parameters are recognized and substandard. While turbidity was 42 NTU -78 NTU, BOD5 4.5 mg/l - 9.1 mg/l, Dissolved Oxygen (DO) 9.1 mg/l - 10.6 mg/l and Phosphate (PO43-) 0.05 mg/l - 0.25 mg/l. this parameter is higher concentration and above standard.

A dataset of land surface water with a spatial resolution of 30 meters on the Qinghai-Tibet Plateau in 2022

The Tibetan Plateau is known as the Asian Water Tower. The distribution of surface water and its changes are closely related to global change, biodiversity and water-related ecosystems. Based on the collection of high-precision land surface water samples, we used the random forest classification algorithm in machine learning to extract land surface water information from Landsat series satellite images and produced a dataset of land surface water with a spatial resolution of 30 meters on the Qinghai-Tibet Plateau based on satellite remote sensing images in 2022. According to data quality assessment, the overall accuracy of the dataset is 92.9%, and the Kappa coefficient is 0.84. This dataset can provide foundational data support for water resource monitoring, ecosystem services, and global change research on the Qinghai-Tibet Plateau.

Domestic water quality and the discriminatory influence of socio-economic stratification on accessibility to safe water in a part of Osun State, Nigeria

The status of the water supplied to households in an urban local government area in southwest Nigeria was examined. Specific objectives were to characterize household water sources, assess the per capita usage of potable water sources and examine quality of the household water in the area. The purposively selected study area, Olorunda local government area in Osun State, Nigeria (being an urban local government area) was stratified into ‘urban core’ (central business district, CBD or high population density area), ‘transition’ (medium population density area but with less social infrastructure) and ‘sub-urban’ (typically government reserved area and low population density area) based on household density and associative socio-economic status. The methods were a mix of questionnaire administration to heads of 120 households (40 per stratum) and collection of the drinking water samples from the supply sources at four randomly selected households in each stratum. The water samples were analysed for the concentrations of nitrite (NO2-), nitrate (NO3-), fluoride (F-), lead (Pb) and arsenic (As) as well as E-coli bacteria contents based on their importance in determining water quality in urban areas. The results showed that domestic water sources are mainly hand dug well (55.8%), borehole (37.5%) and pipe borne (6.7%). Residents averagely consumed at most 4L of water per day. Furthermore, the investigated chemical parameters varied as NO2 (0.37-0.94 mg/l), NO3 (0.29-0.70 mg/l), and F- (0.003-0.97 mg/l). As and Pb occurred in trace quantities, and there were no pollution threats to consumers. The amount of E coli and total coliform contents were however outside the safe limits for residents, suggesting contamination of household water by the bacteria sources. The study concluded communities with low socio-economic status which do not have access to state-provided tap water source are more likely to consume polluted water than those with high socio-economic status or that are supplied with state-provided tap water. The study advocates improve urban water management for the urban fringe dwellers.

Validity of Euphrates River Water within Anbar Governorate, Iraq

This study focusses on the evaluation of the Euphrates River in Al-Anbar Governorate, through the monthly collection of water samples for a full water year from twelve stations extending from Al-Qaiem to Ameria. Because the Euphrates River is the source of water for the residents of the surrounding areas, therefore, continuous evaluation during close periods is necessary. Accordingly, 144 samples were analyzed and their chemical and physical properties were determined. The results showed that calcium and sodium are dominant in the Euphrates River water from positive ions, whereas, sulfates are dominant from negative ions. Euphrates River water in general is clear to cloudy water, low alkaline, fresh water, highly mineralized water to excessively mineralized water, very hard water, and normal sulfate to oligosulfate water. All water samples were within the first class of the Piper diagram represented by Ca2+ - Mg2+ - Cl- - SO42- and fall within the category V (Mixing zone), except for two sites represented in the districts of Rawa and Anah. Euphrates River water achieves a balance between anions and cations, and one does not exceed the other in concentration. According to the cluster analysis method, the hydrogeochemical facies are Ca2+-SO42- and K+; Mg2+ - Na+; and Cl- - HCO3-. The results show that the water is suitable for drinking, livestock feeding, and growing all kinds of crops.

Investigation of high-turbidity tap water problem in Najaf governorate/middle of Iraq

Abstract Turbidity is a fundamental measure for assessing the quality of water supplied by water treatment plants (WTPs) employing a conventional treatment process. If it is present in amounts exceeding the permitted limit, disinfectants are less effective in killing microorganisms and the water becomes unsafe to drink. This article is a part of a comprehensive study that aims to investigate the high-turbidity problem of tap water in two cities of Najaf governorate and offer suitable measures to solve this problem. The purpose of this study was to determine how WTPs impact the turbidity of tap water. The work covered two main WTPs located in Najaf governorate: Unified Najaf and The Old Kufa. It included the collection of water samples from three locations in each plant: the influent of flash mix unit (raw water samples), the effluent of clariflocculation unit (settled water samples), and the effluent of filtration unit (filtered water samples). The samples were analyzed for turbidity using a turbidity meter. The efficacy of each plant's treatment units was revealed by monitoring the turbidity of the water inside each facility. For the Unified Najaf WTP, out of 99 TRE readings, there were 3, 92, and 60 positive values for TREc, TREf, and TREp, respectively. The maximum values of TREc, TREf, and TREp were 22.3, 86.5, and 61.5%, respectively. The performance of Old Kufa WTP was worse than that of Unified Najaf WT. Out of 99 TRE values, the number of positive values was 6, 76, and 31 for TREc, TREf, and TREp, respectively. They also showed that only 26 out of 99 and 9 out of 99 effluent turbidity readings in Unified Najaf and Old Kufa WTPs, respectively, satisfy Iraqi standards for tap water turbidity. The bad performance of the WTPs was the main reason behind the high-turbidity tap water in Najaf governorate. This study identified the causes of that performance and proposed solutions.

Stable Isotopic Evaluation of Recharge into a Karst Aquifer in a Glaciated Agricultural Region of Northeastern Wisconsin, USA

Ground water contamination from septic systems and the application of dairy cattle manure has been a long-standing problem in rural northeastern Wisconsin, especially in areas with thin soils over karstified Silurian dolostone bedrock, where as many as 60% of the wells show evidence of fecal contamination. We present the results of a citizen science supported water-isotope study in Kewaunee County, Wisconsin to evaluate aquifer recharge processes in the critical zone and to demonstrate the viability of time-series stable isotope data as a supplement to traditional water quality indicators in a contamination-prone aquifer. A meteoric water line was also constructed for Green Bay, Wisconsin, providing reasonable isotopic ranges for aquifer recharge events. Volunteer homeowners collected water samples from their domestic wells for a period of ~14 months to provide a measure of long-term isotopic variation in produced water and to determine whether event-driven responses could be identified using δ18O and δ2H isotopic values. Three shallower wells with a prior history of contamination exhibited significant seasonal variation, while the deepest well with the greatest soil thickness (above bedrock) showed less variation. For moderate precipitation events, the shallowest well showed as much as 5–13% of produced water coming from direct recharge, with smaller contributions for deeper wells. Our case study provides a clear example of how citizen science can collect useful time-series isotopic data to support groundwater recharge studies.

Characterization of micro-plastics in water and sediments in Batticaloa lagoon at Kattankudy

Micro-plastics (mps) are a globally ubiquitous contaminant and the occurrence and accumulation of mps in the aquatic environment is nowadays an undeniable fact. The present study intends to address morphological characterization and quantification of micro-plastics at Batticaloa lagoon near Kattankudy municipal dumping sites during the period of September 2019 to February 2020. A one-liter backet and Ekman grab sampler were utilized to collect water samples and sediments, respectively. Density separation was carried out using Nacl solution and all floating solids were subject to a wet per-oxidation method and observed under a stereomicroscope. All the recovered micro-plastics were sorted into categories based on the size (1 mm, 1-2 mm, 2-4 mm) shapes (film, fragment, filament, foam, pellet, microbeads) and colour (white, black, transparent and other colours). Kattankudy sample stations showed mps of 1638.83 ±71.69 items kg^{− 1} in sediment and 1028.33 ± 73.73 items per liter in surface water. Lagoon-shore sample site showed highest number of mps (surface water 691.10 ±28.50 items per liter, sediments 1033.00 ±28.80 items kg^{− 1}) than lagoon sample sites. Overall abundance of mps was statistically significant (p<0.05; one-way Anova) among the study sites. Fragments were the most abundant particle shapes found within the sediments (~33%) and a greater number of films were overwhelmed in surface water (~47%) from both study sites. Less than 1 mm size fraction was the most common in sediments while somewhat larger sizes 2-4 mm was dominant in surface water. An assortment of colors was found in the mps gathered from both surface water and sediment among that in shore ~51% white colour and inside the lagoon ~27% were transparent. This study indicates evidence of micro-plastics pollution present in Kattankudy stations, which calls urgent precautionary measures to mitigate mps pollution. Further research is expected to address real impacts of these micro-contaminants on the lagoon environment in future.

Ant Colony Based Artificial Neural Network for Predicting Spatial and Temporal Variation in Groundwater Quality

The quality of groundwater is of utmost importance, as it directly impacts human health and the environment. In major parts of the world, groundwater is the main source of drinking water, hence it is essential to periodically monitor its quality. Conventional water-quality monitoring techniques involve the periodical collection of water samples and subsequent analysis in the laboratory. This process is expensive, time-consuming and involves a lot of manual labor, whereas data-driven models based on artificial intelligence can offer an alternative and more efficient way to predict groundwater quality. In spite of the advantages of such models based on artificial neural network (ANN) and ant colony optimization (ACO), no studies have been carried out on the applications of these in the field of groundwater contamination. The aim of our study is to build an ant colony optimized neural network for predicting groundwater quality parameters. We have proposed ANN comprising of six hidden layers. The approach was validated using our groundwater quality dataset of a hard rock region located in the northern part of Karnataka, India. Groundwater samples were collected by us once every 4 months from March 2014 to October 2020 from 50 wells in this region. These samples were analyzed for the pH, electrical conductivity, Na+, Ca+, K+, Mg2+, HCO3−, F−, Cl− and U+. This temporal dataset was split for training, testing and validation of our model. Metrics such as R2 (Coefficient of Determination), RMSE (Root Mean Squared Error), NSE (Nash–Sutcliffe efficiencies) and MAE (Mean Absolute Error) were used to evaluate the prediction error and model performance. These performance evaluation metrics indicated the efficiency of our model in predicting the temporal variation in groundwater quality parameters. The method proposed can be used for prediction and it will aid in modifying or reducing the temporal frequency of sample collection to save time and cost. The study confirms that the combination of ANN with ACO is a promising tool to optimize weights while training the network, and for prediction of groundwater quality.

Analysis of chemical variables in the water of the Córrego do Galante Watershed – SP

Population growth accompanied by inefficiencies in the management of sanitary effluents has been triggering adversities in relation to water quality. In view of the above, this work aims to analyze the concentrations of dissolved oxygen and biochemical oxygen demand in the water of the Córrego do Galante Hydrographic Microbasin - SP. Six strategic points were selected to carry out the research, each with its own characteristic, totaling eight collections of water samples, between the months of December/2021 to July/2022. Taking into account the results of the work, it was necessary to carry out an analysis of two chemical variables, which followed specific methodologies. Regarding the Dissolved Oxygen (DO), it was determined by the spectrophotometry methodology of HANNA Instruments, as for the Biochemical Oxygen Demand (BOD), it followed the method described in the Standard Methods for Examination of Water and Wastewater. The lowest DO concentrations obtained were recorded in the Dec/2021 and Jan/2022 periods. In general, over the period studied, the BOD resulted, for the most part, in values ​​outside the limits established by legislation. The period Feb/2022 for point 1 – east – resulted in a concentration of 181 mg.L⁻¹. It is concluded that the Córrego do Galante Watershed is an example of an environment that has been supporting constant anthropogenic impacts, being able to confirm this state through the OD and BOD variables. Among the negative factors, those that most influence the variations in concentrations are the release of sanitary effluent and urban drainage.

Assessing the degradation of environmental DNA and RNA based on genomic origin in a metabarcoding context

AbstractMolecular tools of species identification based on eNAs (environmental nucleic acids; environmental DNA [eDNA] and environmental RNA [eRNA]) have the potential to greatly transform biodiversity science. However, the ability of eNAs to obtain “real‐time” biodiversity estimates may be complicated by the differential persistence and degradation dynamics of the molecular template (eDNA or eRNA) and the barcode marker used. Here, we collected water samples over a 28‐day period to comparatively assess species detection using eDNA and eRNA metabarcoding of two distinct barcode markers—a mitochondrial mRNA marker (COI) and a nuclear rRNA marker (18S)—following complete removal of Arthropoda taxa in a semi‐natural freshwater system. Our findings demonstrate that Arthropoda community composition was largely influenced by marker choice, rather than molecular template, individual microcosm, or sampling time point. Furthermore, although eRNA may capture similar species diversity as the established eDNA method, this finding may be marker‐dependent. Although we found little to no difference in decay rates observed among sample groups (COI eDNA, COI eRNA, 18S eDNA, 18S eRNA), this result is likely due to limitations in the ability of eNA‐based metabarcoding to provide a strong correlation between true eNA copy numbers present in the environment and final read counts obtained (following the metabarcoding workflow). Collectively, our findings provide further support for the use of multi‐marker assessments in metabarcoding surveys to unravel the broadest taxonomic diversity possible, highlight the limitations of eNA metabarcoding methods in providing accurate decay rate estimates, as well as establish the need for further comparative studies using both metabarcoding and single‐species detection methods to assess the persistence and degradation dynamics of eNAs for a diverse range of taxa.

Water Quality Sampling and Multi-Parameter Monitoring System Based on Multi-Rotor UAV Implementation

Water quality sampling and monitoring are fundamental to water environmental protection. The purpose of this study was to develop a water quality sampling and multi-parameter monitoring system mounted on a multi-rotor unmanned aerial vehicle (UAV). The system consisted of the UAV, water sampling and multi-parameter detection device, and path planning algorithm. The water sampling device was composed of a rotating drum, a direct current (DC) reduction motor, water suction hose, high-pressure isolation pump, sampling bottles, and microcontroller. The multi-parameter detection device consisted of sensors for potential of hydrogen (pH), turbidity, total dissolved solids (TDS), and a microcontroller. The flight path of the UAV was optimized using the proposed layered hybrid improved particle swarm optimization (LHIPSO) and rapidly-exploring random trees (RRT) obstacle avoidance path planning algorithm, in order to improve the sampling efficiency. Simulation experiments were conducted that compared the LHIPSO algorithm with the particle swarm optimization (PSO) algorithm and the dynamic adjustment (DAPSO) algorithm. The simulation results showed that the LHIPSO algorithm had improved global optimization capability and stability compared to the other algorithms, validating the effectiveness of the proposed algorithm. Field experiments were conducted at an aquaculture fish farm, and the device achieved real-time monitoring of three water quality parameters (pH, TDS, turbidity) at depths of 1 m and 2 m. A rapid analysis of three parameters (ammonia nitrogen, nitrite, dissolved oxygen) was performed in the laboratory on the collected water samples, and validated the feasibility of this study.

English

The study of a field water sample data collection in poondi reservoir water to mean dissolved oxygen, TDS, pH, TSS, BOD, and COD. The laboratory tested them according to standard parameters described and compared by the Water Quality Standards Bureau of Indian Standards (BIS). In experimental research, a comparison between reservoir water quality parameters was collected for 24 separate sampling stations (12 in Group 1 and 12 in Group 2). The water quality of the poondi reservoir in Tiruvallur district was studied to examine the stability of reservoir water for industrial human usage and agriculture purposes. The beta qualities are 0.05 and 0.2, and G-power is 0.8, respectively, 95% confidence level. Evaluating reservoir water and drinking water standards for which N = 4 samples were taken from each. Drinking water standards for standard parameters compared with the reservoir's water quality have been measured at 7.6, 979, 47, 45, and 320. Within limits of water quality standards, collected water samples in reservoirs in 12 places around the poondi reservoir region. Reservoir water mean value is not equal to the drinking water in Novel treatment. The study mainly focuses on water quality parameters in reservoir water, human use and drinking water sources.

Environmental Quality of Lake Mainit as a Habitat of Indigenous Goby, Glossogobius giuris (Hamilton, 1882) in Northeastern Mindanao, Philippinese

Changes in environmental quality of Lake Mainit could adversely affect the inhabiting organisms like the indigenous goby, Glossogobius giuris or pijanga. Hence, a thorough 16-month (i.e. December 2016 to March 2018) water quality study was undertaken, specifically on obtaining data for water temperature (OC), Dissolved Oxygen (ppm), pH, nitrate (NO3-N, ppm), ammonia (NH3-N, ppm), nitrite (NO2-N, ppm), phosphate (PO4-N, ppm) and light intensity (Lum/ft2) at the seven (7) established sampling stations within the Lake. Standard collection of water samples and their physico-chemical analyses were done and results were compared to DENR standards for freshwater water bodies. Results showed that the water quality of the Lake were still within the desirable range for Class A and Class C waters. This answered the underlying occurrence of fish kills to other factors and not on water quality changes. Highlight of this study is the notable increase of 0.9oC for surface and vertical temperatures of Lake Mainit over a decade and would show a glaring impact of global warming. Based on the 16 months monitoring, turnover occurred once in the Lake, particularly during northeast monsoon, indicating that Lake Mainit is a “monomictic Lake.”

Comparative analysis of discharge and sediment flux from two contiguous glacierized basins of Central Himalaya, India

In the present study, suspended sediment load (SSL), sediment yield and erosion rates in Pindari Glacier basin (PGB) and Kafni Glacier basin (KGB) have been estimated using daily discharge and suspended sediment concentration (SSC) data for three ablation seasons (2017-2019). For this, one meteorological observatory and two gauging sites have been established at Dwali (confluence point), and water samples have been collected twice in a day for high flow period (July to September) and daily for lean period (May, June and October). An area-velocity method and stage-discharge relationship has been established to convert water level into discharge (m3 s-1). For estimating SSC (mg/l), collected water samples have been filtered, dried, analysed and confirmed with an automatic suspended solid indicator. Further, SSL, sediment yield and erosion rates have been computed using SSC data. The results reveal that mean annual discharge in PGB (35.06 m3s-1) has been found approximately 1.7 times higher than KGB (20.47 m3s-1). The average SSC and SSL in PGB have been observed about 396.07mg/l and 1928.34 tonnes, and in KGB, it is about 359.67mg/l and 1040.26 tonnes, respectively. The SSC and SSL have followed the pattern of discharge. A significant correlation of SSC and SSL has been found with discharge in both the glacierized basins (p < 0.01). Interestingly, average annual sediment yield in PGB (3196.53 t/km2/yr) and KGB (3087.23 t/km2/yr) have been found almost identical. Likewise, the erosion rates in PGB and KGB have been witnessed about 1.18 and 1.14mm/yr, respectively. Sediment yield and erosion rates in PGB and KGB have been found in correspondence with other basins of Central Himalaya. These findings will be beneficial for engineers and water resource managers in the management of water resources and hydropower projects in high-altitude areas and in the planning and designing of water structures (dams, reservoirs etc.) in downstream areas.

Epixylic algae and physico-chemical parameters as indicators of aquatic pollution in Elechi Creek, Port Harcourt, Rivers State, Nigeria

Elechi Creek of the Upper Bonny Estuary, Port Harcourt, Nigeria and its resources are economically significant. Still, the Creek is a sink receiving various anthropogenic effluents from its surroundings. The study determined the epixylon assemblage and some physico-chemical parameters [temperature, pH, electrical conductivity (EC), total dissolved solids (TDS), dissolved oxygen (DO), biological oxygen demand (BOD), phosphate, sulphate, and nitrate] of the Creek. Surface water and epixylon sample collections from three stations followed standard methods between August and November 2021. Epixylon samples were analyzed microscopically. A total number of 461 individuals, 30 genera and 37 species from 6 families, namely: Bacillariophyceae (18 species), Chlorophyceae (9 species), Cyanophyceae (5 species), Chrysophyceae (1 species), Dinophyceae (3 species), Euglenophyceae (1 species) of epixylic algae were recorded. Pollution- indicator genera were Cyclotella, Nitzschia, Synedra, Cocconeis, Tabellaria, Melosira (Bacillariophycea) Ankistrodesmus, Chlorella, Closterium (Chlorophyceae), Oscillatoria and Phormidium (Cyanophyceae). Spatially, sulphate (137.02±25.00 mg/L) exceeded the NESREA standard (100 mg/L, respectively), while temperature (30.00±1.72 ℃), pH (6.70±0.79), TDS (2308.92±858.14 mg/L), DO (6.56±0.78), BOD (1.78±0.71 mg/L), nitrate (0.92±0.18 mg/L) and phosphate (0.25±0.06 mg/L) were within NESREA standard (&lt;40 ℃, 6-9, 2000 mg/L, 6.0 mg/L, 3.0 mg/L, 9.1 mg/L and 3.5 mg/L, respectively). EC (4959.50±1836.34 µs/cm) exceeded the WHO standard (900 µs/cm). The presence of dominant Bacillariophyceae, some bioindicator species, and higher EC and sulphate denotes organic pollution in Elechi Creek. The study recommends thus periodic monitoring of Elechi creek and environmental awareness programmes to mitigate pollution and safeguard the health of the residents around this Creek.

Residual status and source analysis of phthalate esters in Ulungur Lake, China.

Ulungur Lake is the largest lake in northern Xinjiang and undertakes important aquatic tasks. It is the No. 1 fishing ground in northern Xinjiang, and the problem of persistent organic pollution in the water has received much attention. However, there are few studies on phthalate esters (PAEs) in the water of Ulungur Lake. Understanding the pollution levels, distribution characteristics and sources of PAEs is of great significance for the protection and prevention of water. Fifteen sampling sites are established in Ulungur Lake to collect water samples during flood and dry periods, then seventeen PAEs are extracted from the water samples and purified by liquid-liquid extraction-solid-phase purification. Gas chromatography-mass spectrometry is used to detect the pollution levels and distribution characteristics of the 17 PAEs and analyse their sources. Results show that the concentrations of PAEs in the dry and flood periods are 0.451-9.97µg/L and 0.0490-6.38µg/L, respectively. The concentration of ∑PAEs with time is characterised by the dry period > the flood period. The change in flow is the main reason for the diverse concentration distributions of PAEs in different periods. The concentration of ΣPAEs in the dry period is much lower on the side near the lake entrance of the Ulungur River and Irtysh River. In the dry period, PAEs mainly come from chemical production and the use of cosmetics and personal care products; in the flood period, they mainly come from chemical production. River input and atmospheric sedimentation are the main sources of PAEs in the lake.