Selected Water Quality Parameters Research Articles

Trends in Water Quality in a Tropical Kenyan River-estuary System: Responses to Anthropogenic Activities

Aims: To determine the spatial variation in physico-chemical water quality attributes in estuarine ecosystems of South Coast Kenya to inform its management. Study Design: We employed diagnostic research design where such factors as anthropogenic activities, hydrology, and accessibility were considered in choosing 12 sampling stations. A mixed sampling design (probability and non-probability) was used to sample. Place and Duration of Study: Four discharging rivers into estuarine system with a reference point were identified. 12 sampling points were earmarked and sampled for 12 months. Methodology: Nine selected water quality parameters were collected in triplicates monthly for 12 months. Temperature, dissolved oxygen, pH, conductivity, salinity and TDS were collected in situ using YSI Multiparameter meter (Professional plus) while nutrients were analyzed in the laboratory calorimetrically. Data was tested for normality and homogeneity of variances using Levene's and Shapiro-Wilk tests. Two-way analysis of variance (ANOVA), and Principal Component Analysis (PCA) were done using the 64-bit R Software version 4.3.0 to test for significant differences and correlate the parameters among the sampling sites respectively. Observed differences were considered statistically significant at P < 0.05. Results: The measured environmental variables differed significantly among the sampling stations (P < 0.05). temperature and salinity exhibited moderate to strong effect on water quality, while pH and nutrients (phosphates, nitrates, and ammonia) exhibited mixed effects with both negative and positive loadings on the Principal Components. It is demonstrated that the south coast estuary, Kenya is affected by two gradients: mineralization from the sea and the organic matter gradient at the upstream stations dominated by the fluvial inflows from the respective rivers. Conclusion: The south coast of Kenya estuary is impacted by natural processes and anthropogenic activities. we recommend for continued regular water quality assessment and monitoring to acquire sufficient data to shape policy frameworks towards its sustainable management.

Impacts of flow regime characterization on selected water quality parameters in Mthatha River catchment

Abstract The effects of altered streamflow types on selected water quality parameters provide useful knowledge and information for prompt water pollution management. This study assesses the impacts of inter- and intra-year seasonal variability in streamflow types on selected water quality parameters. The study uses percentiles, multivariance correlation, and agglomerative hierarchical clustering analysis (AHC) in XLSTAT statistics software to achieve the study aim. Historical dataset for streamflow, rainfall, and selected water quality parameters between 2012 and 2020 for the Mthatha River catchment (MRC), Eastern Cape, South Africa were used to characterize the different seasonal variability impacts with the selected water quality parameters at both the upper and lower reach of the river. The result of the inter and intra-year seasonal variability analyses show that the catchment's flow magnitude varies between 2.0 and 2.7 m3/s in summer while the results of the nonlinear polynomial relationship between the grouped streamflow regime show a coefficient of correlation (R2) values of 0.4264 and 0.5643, suggesting that a mild alteration occurs in the catchment. Decision-makers would find the study useful in controlling the pollutant effluent discharge into the river at different times and maintaining standard effluent requirements as mitigation strategies for sustaining the river ecosystem.

A preliminary study of direct observation and selected water quality monitoring in Putrajaya Lake: the status between October-December 2022

The objective of this study was to provide the status of water quality based on a direct observation and selected water quality parameters (nitrite, ammonia, and pH) monitoring study between October-December 2022. Between October and November 2022, the levels of the above three surface water quality parameters were measured in 6 different sites throughout Putrajaya Lake. Observational pictures of the sites were also taken, and water samples were collected. In addition to the above observation and water quality monitoring study, the rainfall data was collected from 17th October 2022 to 11th December 2022, cited from the official website of Public Infobanjir (https://publicinfobanjir.water.gov.my/?lang=en) at stations Sg. Anak Gajah and Sg. Limau Manis, was also used to understand the possible correlation. However, further studies are needed. It was found that the water quality status was in good condition, making Putrajaya Lake a safe and suitable lake for aquatic life and recreational activities between October -December 2022. This could be due to the sustainable practices and rainwater harvesting system already implemented at Putrajaya Lake. Putrajaya Lake's water quality monitoring and sustainability practices were well implemented. However, regular maintenance to provide acute monitoring of water quality data at Putrajaya Lakes is necessary in the future.

Assessment of the status of selected heavy metals in water, sediments and a fish species (Oreochromis niloticus) of commercial value in Lake Nakuru with a focus on human health risks

AbstractThe present study presents selected water quality parameters and the levels of heavy metals in water, sediments and Nile tilapia (Oreochromis niloticus) of Lake Nakuru. Nine sediments and nine water samples, as well as 30 specimens of Nile tilapia, were collected from the northern part of the lake. Physical parameters were measured in situ using multiple probes and metres. Heavy metals were analysed using an atomic absorption spectrophotometer (AAS). The pH, dissolved oxygen concentration, temperature, salinity and electrical conductivity ranged from 9.52 to 9.72, 4.58 to 8.62 mg/L, 23.40°C to 25.7°C, 2.39‰ to 2.81‰ and 4470–5226 μs/cm, respectively. Heavy metal levels (mean ± SD) were generally low in the water samples. Chromium values ranged between 7.16 and 9.19 mg/kg dw in sediment samples, and between 3.7 and 13.06 mg/kg dw in fish samples. Lead values ranged between 12.5 and 31.04 mg/kg dw in sediment samples and 4.06 and 9.95 mg/kg dw in fish samples. Arsenic values ranged between 9.5 and 21.7 mg/kg dw in sediments and below detectable limit to 2.11 mg/kg dw in fish samples. Mercury values ranged between .14 and .31 mg/kg dw in sediment samples and .12 and .35 mg/kg dw in fish samples. Cadmium was the only heavy metal concentration that was below the detection limit in the three matrices. Significant differences were observed for some heavy metal concentrations in water, sediments and fish across sites (p < .05). The levels of lead and chromium in fish were above the East African Standard, World Health Organization and European Union limits. The results of the present study recommend a possible reclassification of the lake, an immediate ban on fish harvesting and consumption from Lake Nakuru and a policy intervention on the fishery and pollution management.

Environmental implications of salinity and flooding induced changes in porewater nitrogen and phosphorous dynamics

ABSTRACT This study aimed to investigate the effects of fresh water and seawater flooding on phosphorous (P) and nitrogen (N) dynamics in two calcareous soils (Biscayne and Krome) of South Florida using a 28-day greenhouse flooding experiment. Porewater samples were collected at three depths over four periods (1, 7, 14, and 28 days) of flooding and analyzed for selected water quality parameters. Results showed that seawater-flooded Biscayne soil had a 4.4 fold higher porewater soluble reactive phosphorus (SRP) concentration than freshwater. Additionally, porewater SRP concentration and total phosphorus (TP) in Biscayne soil increased with prolonged flooding duration and column depth. Furthermore, both freshwater and seawater flooding increased porewater NH4 + - N concentration; however, the increase was more pronounced in seawater flooded samples. NH4 + - N concentration also increased with flooding duration. Overall, the study highlights the risks of nutrient leaching from seawater flooded coastal soils that could contribute to the deterioration of surface and groundwater quality.

The relationship between water pressure variations and drinking-water quality in small water supplies: A case of Mukono District, Uganda

The supply of a safe and adequate quantity of water is essential for human health and socioeconomic development. Physiochemical and microbiological quality of water supplied in piped distribution systems can be affected by long water residence times and travel distances. This may be due to low pressure, reservoir storage and insufficient disinfection in the system among other causes. As such, large schemes usually have mechanisms of improving the quality of water along supply and/or distribution networks at reservoir and other points. In contrast, small, piped water supply schemes rarely have the infrastructure and resources to monitor and provide treatment to the water in distribution. The objective of this study was to assess the variation of water quality and water pressure along the supply network in small, piped water systems. The study used mixed methods of quantitative water quality and pressure assessments, alongside stakeholder interviews, to investigate the variability of water pressure and specific water quality parameters across the distribution network, and reliability of supply in two different small water supply schemes in the study area of Mukono, Uganda. Results showed water pressure in small, piped water supply networks have minimal influence on variation of selected water quality parameters in smaller (< 4000 m travel distances) and well operated and maintained systems. A pressure drop from 82.2 m to 22.5 m changed Turbidity by < 1, Apparent Color by < x10 and Total Dissolved Solids by < x102. Proper management of supply systems to ensure optimal residual and continuous pressure can safeguard the quality of water in the distribution systems of small piped water networks against intrusion of contaminants. Good management practice that utilizes historical operational data with continuous capacity development and training support on water quality and pressure fluctuations can significantly improve system performance to meet acceptable standards.

Assessment of Spatial and Temporal Variation in Water Quality for the Godavari River

With increasing population and industrialization, the water quality of freshwater sources like rivers, lakes, and ponds is becoming increasingly degraded. Most of the rivers in India are becoming polluted, including the Godavari. With the construction of dams, new industries and unsustainable agricultural practices in the Godavari basin, the water characteristics are degrading spatially and temporally. The present study emphasizes the analysis of water quality parameters like temperature, pH, Dissolved Oxygen (DO), conductivity, Biological Oxygen Demand (BOD), nitrate, and faecal coliform concentration in the Godavari basin. This was achieved by analysis of data taken from the Central Pollution Control Board, India (CPCB) for 21 stations around the Godavari basin over a span of five years from 2015 to 2019. The Pearson Correlation coefficient for the water quality parameters was assessed to study the relationship among the parameters. Variation in the water quality parameter is observed from the graphs for each station for respective years. It was found that conductivity and DO, temperature and pH and DO and faecal coliform are negatively correlated. It was also observed that DO has a negative correlation with pH, BOD and faecal coliform, indicating the utilization of dissolved oxygen at higher rates due to increasing degradation of organic matter by aerobic microorganisms in the river. One-way ANOVA was applied to find out significant temporal variations and it was observed that temperature, pH, and faecal coliform level had significantly changed the overdue course of time (F(4, 115) = 2.451, p &lt; 0.05). The obtained results from the analysis indicate that the selected water quality parameters have varied significantly spatially, whereas temporally, according to the ANOVA coefficient, only temperature, pH and faecal coliform had shown significant differences during the selected timeframe. Hence, the present study highlighted the deteriorating water quality of the Godavari River over time.

Use of water accounts based indicators for water management in India

AbstractIn India, water accounts on a river basin scale are not prepared regularly, mainly due to the unavailability of data on consumptive uses in various economic sectors at that scale. This research paper demonstrates an approach to prepare water accounts for the Mahanadi river basin in eastern India, which experiences climate‐induced hydrological extremes using the demographic, economic, hydrological, and geohydrological data available at different administrative and geographical scales. Further, selected water accounts derived indicators were computed to identify critical elements that need to be altered for improving water resources management at the river basin scale. The results show that the total inflow during the wet year exceeds 24%–26% in comparison to the normal and dry years. In turn, 23% and 24% of the inflow get drains to the sea in a dry and normal year, respectively, with agriculture accounting for the lion's share of the blue water consumed, about 57%–60% in all the years. The river has a huge dilution capacity, and, except for the biological oxygen demand in a dry year, the value of all other selected water quality parameters (nitrogen and electrical conductivity) is within the acceptable limits established by law. Reducing water consumption in irrigated crops during summer, controlling evaporation from the reservoirs, and considering nitrogen concentration and electrical conductivity in the existing approach to determine polluted river stretches in India are identified as crucial actions for improving water management in the basin. Further, assessment of water consumption and environmental flow requirement is identified as important decision factors to guide future water reallocation among riparian states.

Spatial analysis of groundwater quality in Bulawayo, Zimbabwe: Geogenic and anthropogenic contributions

Over-exploitation of groundwater owing to urbanisation and industrialisation compromises its quality, spatially and temporally. The objective of this study was to analyse the spatial groundwater quality due to geogenic and anthropogenic activities in Bulawayo, Zimbabwe. Eighty boreholes were mapped and sampled for selected water quality parameters. The groundwater quality parameters that were adopted in this study were the temperature, electric conductivity, dissolved oxygen, pH, bicarbonate alkalinity, chloride, sodium, calcium, magnesium, sulphates, chlorides, potassium, iron, nitrates, fluoride, phosphates, arsenic, aluminium, zinc, strontium, barium and manganese. Groundwater samples were evaluated for drinking water suitability as per the 2011 World Health Organization (WHO) guidelines. Prediction of groundwater quality parameters at unsampled points was achieved by using the Inverse Distance Weighted interpolation method using Geographic Information Systems (GIS) software. Population, land use and geological data were superimposed onto the groundwater quality to generate integrated maps. There were noticeable distinctions in groundwater quality within different geological areas, particularly for fluoride, arsenic, sodium, calcium, chloride and strontium, signifying natural groundwater contamination. High levels of nitrate were detected near agricultural areas and in medium to high-density residential areas suggesting possible contamination from nitrogenous fertilizers and leakages from wastewater infrastructure respectively. The application of GIS to spatially map water quality, can be used by hydrogeologists and local authorities in planning, monitoring and protecting groundwater resources.

Influence of Culture Tank Colours on the Water Quality, Growth Performance and Feed Utilization of Oreochromis niloticus (Linnaeus, 1758) Juveniles

The study was conducted over a period of fifty-six (56) days to investigate the effects of different colours of culture tanks on the water quality, growth, and feed utilization of Nile tilapia (Oreochromis niloticus) juveniles. O. niloticus of mean body weight of 8.5g were stocked and fed twice daily with a commercial diet containing 42% crude protein. The experiment had four treatments based on tank colours; white, green, black and blue coloured tanks. Some water quality indices were assessed once in a week while the fish were weighed at the end of the experiment to compute the performance indices. The data were presented using mean and standard error and comparative analysis was done using one way ANOVA at 95% confidence interval with Duncan multiple range test as the follow up test. The water quality parameters examined during the study were not significantly different among the treatments. All the selected water quality parameters were within the acceptable range for tropical fish culture. While there was no significant difference in final weight, weight gain, percentage weight gain, and specific growth rate among the treatments, black tanks showed slightly higher values with 10.89±0.89 g, 2.54±0.94g, 30.47±11.43%, and 0.47±0.16%/day, respectively. Higher feed intake and FCR were recorded in green tank (10.08±0.61 g and 7.92±2.70 respectively) and the least was observed in black tank (9.32±0.12g and 4.23±1.51). The percentage survival of the fish was different significantly among the treatments (P&lt;0.05). Fish reared in white background showed the highest survival (100%) which was different significantly from all other treatments. The blue and black tanks showed slightly higher values of viscerosomatic index and hepatosomatic index with 7.22±1.00% and 2.02±0.25%, respectively, while black and white tanks had the least values with 4.44±1.11% and 1.64±0.15%, respectively. The results showed that O. niloticus juveniles can be reared in all the tanks with no negative implication on their performances. However, black and white tanks showed better potential towards improved growth and feed utilization, while white tank led to better survival rate and tended towards better well-being as indicated by the skin pigmentation and hepatosmatic index. Therefore, rearing of O. niloticus juvenile in white tank is recommended over other colours.

Water Renewal Frequency Affects Water Quality, Growth Performane and Physiological Staus of African Catfish, &lt;i&gt;Clarias gariepinus&lt;/i&gt; Juveniles

A 56-day experiment was undertaken to assess the influence of water changing frequency on the water quality, growth performance and physiological status of African catfish, Clarias gariepinus juveniles. There were three treatments with different water changing regimes, every two days, every four days and once a week. Nine plastic tanks were stocked with ten African catfish (10.39±0.36 g) each in triplicates for the three treatments. The fish were fed at 5% body weight daily. Selected water quality parameters were examined twice a week, while growth performance and physiological parameters were measured at the end of the eight weeks. pH, temperature and nitrate-nitrogen were not different significantly among the treatments. The highest total ammonia-nitrogen (0.55±0.01 mg L-1 ) was observed in the treatment with water changes once a week, and it was significantly higher than the treatment with water changes every two days. Both total dissolved solids and electrical conductivity were also different among the treatments. Growth performance improved with decreased frequency of changing water; weight gain, specific growth rate and yield were all higher significantly in the treatment with water changes once in a week compared to every two days. Nutrient utilization, survival and body indices were not different significantly among the treatments. Higher glycogen and healthier livers were noted in the treatment with water changes once a week. The result established that changing the water once a week for fish stocked up to 20 Kg m-3 may confer more advantages on the fish and lead to improved performance.

Water Quality of the Odra (Oder) River before and during the Ecological Disaster in 2022: A Warning to Water Management

Aquatic ecosystems are under pressure due to human activity. In the summer of 2022, the Odra River (Central Europe) suffered a massive death of fish and mollusks. This paper aims to show selected water quality parameters before and during the ecological disaster and find which parameters may have been crucial to the development of this disaster. We used the Kruskal–Wallis test and Spearman’s correlation to check the water parameters’ spatial and temporal diversification. In addition, non-metric multidimensional scaling was performed. The water quality parameters of the Odra system were analyzed in sections: middle Odra, lower Odra, transitional waters, and Szczecin Lagoon. Human activity has led to the formation of a system with unusual characteristics, disturbing the river’s natural continuum and related processes. The year 2022 in the middle Odra differed from the previous years in having a high water temperature (&gt;24 °C), high ammonium concentrations (&gt;4 mg/L), and relatively low nitrate concentrations (&lt;6.5 mg/L). At the same time, salt pollution in the river was very high (maximum 1.4 g/L). In June and July 2022, we observed low chlorophyll a concentrations in the middle Odra (on average 2.3 µg/L and 4.4 µg/L, respectively), presumably due to salinity stress and high temperatures, suppressing freshwater phytoplankton taxa. This circumstance has created the appropriate conditions for developing euryhaline and thermophilic Prymnesium parvum. Because of decaying organisms, hypoxia occurred in the lower Odra (0.26 mg/L of dissolved oxygen in surface waters), and oxygen conditions worsened in the transitional waters (&lt;4 mg/L). The zonal deaths of fish and mollusks result from multiple stressors induced by human activity. This disaster has proven that it is necessary to improve selected water quality parameters to reduce the risk of such disasters. The most urgent recommendations are to reduce the salt pollution of the upper section of the Odra, reduce nutrient inputs, and improve the condition of smaller rivers feeding the main course of the Odra.

Integrated multitrophic culture of shrimp Litopenaeus vannamei and tilapia Oreochromis niloticus in biofloc system: A pilot scale study

Shrimp production in biofloc systems generates excess organic matter that must be removed from the system. Due to its ability to consume natural productivity, the integration of tilapia in shrimp culture could help to reduce the levels of total suspended solids in the biofloc system. The present study aimed to evaluate two stocking densities of tilapia in an integrated culture with shrimp Litopenaeus vannamei reared in a pilot-scale biofloc system. Two stocking densities of tilapia were tested, 35 and 65 fish m-3 in a recirculating system with 10 m3 tanks for shrimp culture and 4 m3 for tilapia culture with water recirculation of 965.66 ± 92.83 L h-1 during 78 days. The initial weight of shrimp was 0.9±0.1 g and of tilapia was 7.1±3.2 g. Shrimps were fed according to the feeding table and fish were underfed to stimulate bioflocs consumption. Selected water quality parameters were monitored during the trial. Tilapia densities did not affect shrimp growth (11.5±1.9 g and 10.1±0.7 g for 35 and 65 fish m-3 treatments, respectively). The tilapia presented a FCR lower than 1, proving that bioflocs were consumed by fish. The clarification time was shorter when compared to other studies with shrimp monoculture. Between the treatments, a reduction of 10 hours in the system clarification occurred when lower fish stocking density was used. The results demonstrate the feasibility of integrated shrimp and tilapia culture on a pilot scale, without compromising shrimp productivity.

Comparative Analysis of Natural and Synthetic Zeolite Filter Performance in the Purification of Groundwater

Zeolite materials are among the relatively cheap and readily available materials for wastewater treatment. However, the performance of zeolite-based systems can be highly affected by the material properties. In this study, the treatment system based on natural zeolite materials from Chankanai mines in Kazakhstan was compared with a synthetic zeolite treatment system for the purification of groundwater. Water quality indices were also developed from a set of selected water quality parameters to further assess the state of water quality of raw groundwater and the effluents treated with natural and synthetic zeolite. The lowest removal efficiency of natural zeolite (30%) was observed with zinc, while the lowest removal efficiency (36%) of synthetic zeolite was observed with arsenic. With turbidity and beryllium, we observed the maximum removal efficiency (100%) of natural zeolite, whereas with turbidity, we observed the highest removal efficiency (100%) of synthetic zeolite. When the groundwater samples were put through the natural zeolite treatment system, removal efficiency of 50% and above was obtained with 27 (79.4%) out of the 34 water quality parameters examined. On the other hand, when the groundwater samples were put through the synthetic zeolite treatment system, more than 50% removal efficiency was attained with 30 (88.2%) out of the 34 water quality parameters studied. The aggregated water quality index of raw groundwater was 3278.24, falling in the “water unsuitable for drinking” category. The effluent treated with natural zeolite generated 144.82 as a water quality index, falling in the “poor water” quality category. Synthetic zeolite generated 94.79 as a water quality index, falling in the “good water” quality category. Across the board, it was shown that the synthetic zeolite treatment system outperformed the natural zeolite treatment system according to a number of water quality parameters. The findings of this study offer substantial knowledge that can be used to develop more efficient groundwater treatment technologies.

Limnological variables as a determinant of fish parasites abundance in the Esa-Odo reservoir, Esa-Odo Southwestern Nigeria

Abstract This study investigated fish parasites in relation to limnological variables of the Esa-Odo reservoir since the quality of the aquatic environment might influence parasitic infestation in fish. The purpose of this study was to provide information on the parasite species of the reservoir due to their public health concern and their relationship with selected water quality parameters. The water quality and parasite examinations were analyzed based on standard protocols in the laboratory. The results showed that water quality parameters were not significantly different (p &amp;gt; 0.05) across the zones. Seasonally, mean water temperature, pH, TDS, DO, organic matter, COD and turbidity were significantly different (p &amp;lt; 0.05) across the different zones of the reservoir while electrical conductivity, alkalinity, NO3-, and PO43- were not significantly different (p &amp;gt; 0.05). Clinostomum tilapiae, Clinostomum sp., Euclinostomum heterostomum, Procamallanus laevionchus, and Lytocestus sp. were recovered in all the fish sampled. The overall prevalence of the fish parasites was 9.8% with an intensity of 2.13. The result indicated fish parasites had a strong positive correlation with certain water quality properties and parasite abundance which suggested that water quality could determine parasitic loads in fishes of the Esa-Odo reservoir.

Citizen Science for Water Quality Monitoring in the Meki River, Ethiopia: Quality Assurance and Comparison with Conventional Methods

A lack of water quality information for many water bodies around the world makes it difficult to identify global change and discover early signs of myriad threats to freshwater resources. This problem is widely seen in Ethiopia due to absence of regular monitoring. Citizen science has a great potential to fill these gaps in water quality data, but there is concern about the accuracy of data collected by citizen scientists. Moreover, there is a gap to engage citizen scientists in water quality monitoring, and there is still insufficient awareness of how citizen scientists can become part of a collaborative scheme. This study aimed to evaluate the accuracy of water quality collected by citizen scientists and characterize the water quality of the Meki River with the involvement of citizen scientists. The suitability of the river water for irrigation was evaluated using a combination of citizen science and conventional water quality data collection methods. Water temperature, turbidity, ammonia, phosphate, nitrate, nitrite, total alkalinity, total hardness, and pH were analyzed by both citizen scientists and in a conventional laboratory. The citizen scientists’ data, expressed as percent of synthetic standard solution concentrations, indicated good agreement for selected water quality parameters: 123.8 ± 24.7% for PO43−, 115.6 ± 6.3% for NO3−, 105.8 ± 7.4% for pH, and 133.3 ± 23.6% for NH4+. Thus, citizen scientists can monitor and collect water quality data accurately. From the results, the Meki River water can be used for irrigation, but pollution sources should be controlled to reduce further quality deterioration as the population increases.

Time series trend modelling and forecasting of selected water quality parameters in the Mthatha River Catchment, South Africa

Abstract Over recent decades, water quality at the Mthatha River Catchment (MRC) within the Eastern Cape Province of South Africa has been threatened by various pollutants. The continuous effluent concentration discharges from the Mthatha Prison and the Efata School for the Blind and Deaf have caused ineffable damage to the Mthatha River's water quality. Thus, the time series-measured data between 2012 and 2020 were analysed to determine the trends and enable forecasting of selected water quality parameters using the Thomas–Fiering (T–F) stochastic model. The Kendall's τ test trends show an increase in the coefficient of variation of 0.498 and 0.394 at the Mthatha Prison and Efata School, respectively, for abrupt changes, whereas the mean monthly T–F forecasted model shows a good correlation value range from 0.79 to 0.87 for the various predicted variables. The simulated predicted models and trends could serve as a measure to forecast selected water quality parameters' occurrence and a likelihood period when the river pollutants could be controlled. Water managers and researchers would find usefulness in the employed tools for an effective control planning of the river pollutants.

COVID-19 lockdown affects zooplankton community structure in dolphin appearing site of the River Ganga at Patna

Abstract The advent of the 2019 Corona virus impacted day-to day human activities and the nationwide lockdown in India completely paralyzed life (midnight of 24th March, to 31st June, 2020). However, this complete halt of human activity allowed the Ganga ecosystem to realise its maximum self-purification potential, resulting in the improvement of flow regime, water quality and over all restoration of the river. The most common manifestation of restoration of an aquatic ecosystem is zooplankton community structure; i.e. relative proportion of various functional feeding groups. The present study compares selected water quality parameters (DO, BOD, pH, Total coliform, Fecal coliform), and zooplankton community structure estimated during the lockdown period with the values recorded for the same period in previous three years at dolphin appearing site near Kalighat, (25° 37’ 19.398’’ N; 85° 9’ 55.8972’’ E), middle of the Patna city and Mittal Ghat (downstream site of the Patna City) at Gurhatta (25° 36’ 24.5772’’ N; 85° 13’ 1.6788’’ E). During each sampling, the dolphin emergence site and frequency were monitored for three hours duration. Monthly zooplankton samples were collected at both the sites using a 53 µm mesh size plankton net beginning January 2018 by filtering 45-50 l of river water. Zooplankton were identified and segregated based on functional feeding groups. The values of dissolved oxygen were significantly higher, whereas that of BOD level, total coliform and total fecal coliform were lower during the lockdown period than those in previous years. Detailed analyses revealed that relative proportions of Cladocera were significantly higher, whereas that of bacterivorous Rotifera were significantly lower than the previous values of the same months. The highly indicator species at both the sampling sites was Moina micrura during March-May 2020; in previous years it was Brachionus rotifers 8.8 (ind l-1) at Kalighat and Moina micrura (15 ind l-1) at Gurhatta. Our results suggest that during the lockdown the dolphin appearing sites at both stations shifted towards the riverbank whereas, zooplankton community structure changed towards algaevorous Cladocera without affecting overall species richness.

Application of QUAL2kw and Forecasting models for assessment of pollutants in upper Athi River catchment in Kenya

Water pollution in the Athi river drainage basin, the fourth largest drainage basin in Kenya, has the potential of adversely impacting the aquatic biota and communities living downstream of the river. The upper part of the basin has experienced rapid industrialization in the recent past and there has also been increased encroachment of wetlands and forests for agriculture and settlement to cater for the increased population. The objective of this study was geared towards the generation of scenarios to predict future water quality trends in the upper parts of the Athi river basin. The prediction of the future water quality trends was undertaken in two phases: (i) the development of longitudinal water quality profile using QUAL2Kw model and (ii) prediction of the future water quality trends using the SPSS Forecasting tool. The collection of water quality data in established sampling stations located in the upper parts of the basin was carried out between January and December 2018. The archival data for the period 2015-2018 was obtained from Water Resources Authority (WRA) database for the determination of future trends in selected water quality parameters. The correlation analysis between the observed and predicted water quality parameters yielded strong R2 values for temperature-0.82, electrical conductivity-0.99, total dissolved solids-0.94, biochemical oxygen demand-0.66, chlorophyll a-0.89, total nitrogen-0.75 and total phosphorous-0.94. The standard error ranged between 0.01-0.42, indicating that the model is reliable for predicting water quality parameters in the river. The available archival monthly data from 2015 to 2018 were averaged for time series forecasting to generate future water quality scenarios of the river for the period 2019-2030. The results showed that dissolved oxygen exhibit a decreasing trend in future indicating depletion of oxygen in water. There will also be significant increasing trends for Electrical Conductivity, Total Suspended Solids, Biochemical Oxygen Demand and Iron in future. There is a risk that the pollutants will increase to unsafe levels in the Athi River if appropriate management actions are not taken by the concerned agencies

Influence of Land Use Cover on Selected Water Quality Parameters of River Isiukhu, Kenya

Influence of Land Use Cover on Selected Water Quality Parameters of River Isiukhu, Kenya