Great River Research Articles

Assessing the impact of human activities on the health condition of the Lukosi River catchment using selected physico-chemical parameters as indicators of water quality

The Lukosi River catchment plays a crucial role in the economic and ecological framework of the country, serving as a major contributor to the Great Ruaha River (GRR). This study aimed to assess the impact of human activities on the health of the Lukosi River by analyzing key water parameters. Three sampling sites across the catchment were selected, and water samples were collected and analyzed using the American Public Health Association technique. A one-sample t-test was used to measure the significance of the difference between the measured water quality parameters and the water quality criteria established by the Tanzania Bureau of Standards (TBS) and the World Health Organization (WHO). The results revealed mean values for various parameters: pH (8.67 ± 0.57), temperature (24.803 ± 1.361°C), EC (93.30 ± 3.34 mgL−1), BOD (14.85 ± 1.49 mgL−1), TDS (46.95 ± 1.55 mgL−1), total hardness (27.53 ± 1.28 mgL−1), DO (3.4 ± 0.53 mgL−1), turbidity (109.83 ± 40.99 mgL−1), NO2 (79.04 ± 0.73 mgL−1), Cu (6.07 ± 0.60 mgL−1), Ca (7.88 ± 0.36 mgL−1), Mn (0.16 ± 0.07 mgL−1), Cl (7.58 ± 3.97 mgL−1), F (0.12 ± 0.0008 mgL−1), SO4 (20.42 ± 4.12 mgL−1), Mg (1.92 ± 0.13 mgL−1), Zn (0.14 ± 0.11 mgL−1), Fe (3.56 ± 0.15 mgL−1), and NH3 (4.67 ± 0.51 mgL−1). Parameters such as DO, turbidity, NH3, NO3, and BOD significantly (p = 0.05) exceeded the permissible limits set by the TBS and the WHO. Furthermore, elements including Fe and Cu exceeded allowable limits. Moreover, the WQI was used to indicate that the water in the catchment is unsuitable for sustaining aquatic organisms and is unfit for domestic use. Household questionnaires and direct observations identified key human activities in the catchment: gardening (78.3%), agriculture (68%), livestock keeping (50%), sand mining (21%), and brick-making (21%). Less prevalent were car washing (7%) and fishing (4%). These findings underscore the urgent need for conservation efforts and sustainable management practices to safeguard the Lukosi River catchment (LRC).

Ecomorphology of Longnose Gar (Lepisosteus osseus): on the influence of size, sex, and river location

AbstractEcomorphology is essential to understanding the evolution and biogeography of species. However, morphological studies that focus on nongame or ‘rough’ fish groups such as Gar (Lepisosteidae), outside of a phylogenetic context, are comparatively rare. Herein, we investigate the effects of sex, size, and location in a river to assess the potential for sexual dimorphism, allometry, habitat, or some combination to drive observed morphologic variation. Our dataset includes 230 Longnose Gars (Lepisosteus osseus) made up of both males and females of a wide range of sizes collected from three different sites corresponding to the upper, middle, and lower Great Pee Dee River in South Carolina. Dorsal and lateral photographs were taken from each specimen and landmarked for 2D geometric morphometric analyses. Discriminant function analyses (DFA) were also conducted on a few linear trusses to compare the accuracy of sex-related shape aspects that emerged from morphometrics as a possible field-based tool to help fisheries managers understand their stock populations. Overall, location was a statistically significant predictor of shape, yet the differences were not biologically meaningful. Additionally, sex and size were strong predictors of shape, with the greatest differences seen in the largest individuals. DFA of field measurements found that the Snout Length-to-Total Length ratio accurately predicted sex 71% of the time, with females having longer snouts than males. Differences in ratio between sexes can allow tentative sex assignments without lethal gonadal inspection. This study presents the first standardized whole-body 2D geometric morphometrics protocol for Longnose Gar.

Spatio-Temporal Differentiation and Driving Factors of County-Level Food Security in the Yellow River Basin: A Case Study of Ningxia, China

Food security is the primary condition for the development of human society. The Great River Basin is very important to ensure the accessibility and availability of agricultural irrigation, which is vital for food security. The Yellow River Basin plays a significant role in China’s food security, with counties serving as key administrative units for guaranteeing this security. This study uses the Yellow River Basin in China as a case study to construct an evaluation index system for county-level food security. It assesses the food security of 22 counties (districts) in Ningxia from 2013 to 2022, applying spatial correlation theories and driving factor analysis methods to explore the factors influencing county-level food security. The results reveal the following: (1) Overall, the food security index in Ningxia has been on the rise, but there is significant internal variation among counties. (2) Spatially, the food security index is relatively low in administrative centers, while the irrigation areas along the Yellow River play a crucial role in maintaining food security, and the overall food security index in the central arid areas is improving. (3) Food security is driven by multiple factors including economic, social, and climatic influences. To enhance food security in the Yellow River Basin, it is necessary to manage land resources systematically, improve grain production technology, and balance ecological protection with food security.

Assessment of water quality in the Great Zab River (Erbil city, Iraq) exposed to wastewater from different industries using the WQI and GIS-based Python script approaches

ABSTRACT This study was conducted to assess the water quality of the Great Zab River (GZR) under potential pollutant pressure from some industries. The Water Quality Index (WQI) was used to evaluate the results of the water quality monitoring study. WQI and Geographical Information System (GIS)-based Python scripts were used to evaluate the results. Results indicate varying water qualities, ranging from moderate to poor, with fluctuations attributed to pollution from industrial plants mixing with river water. The WQI rating of the GZR before industrial discharges was 57.48, and in the lower part, after discharges, the WQI rating was 56.00, indicating marginal water quality. In contrast, the areas near the Cola Factory, where the river confluence occurs, have WQI values of 43.32 and 44.97, representing unacceptable, poor water quality. The study highlights that the refinery, Cola factory, and power plant locations significantly impact the river's water quality. These findings underscore the urgent need to adopt ecological practices, establish environmental regulations, and implement sustainable technologies to preserve the river's natural state. Concise measures aimed at eliminating pollutant sources and enhancing environmental awareness within communities are essential for the conservation of the GZR and the the protection of its surrounding ecosystems. surrounding ecosystems.

Accelerated warming of High Mountain Asia predicted at multiple years ahead

High-Mountain Asia (HMA) is an important source of freshwater since it holds the largest reservoir of frozen water outside the polar regions. HMA feeds ten great rivers, ultimately supporting more than 2 billion people. However, the threat of accelerated glacier melt, which is a consequence of unprecedented global warming since the early 1950s, threatens water resources in the surrounding countries. Accurate predictions of the near-term temperature change and synergistic mass loss of glaciers are essential but challenging to implement because of the impacts of internal climate variability. Here, based on large ensembles of state-of-the-art decadal climate prediction experiments, we provide evidence that the internally generated surface air temperature variations in HMA can be predicted multiple years in advance, and the model initialization has robust added value to the decadal prediction skill. Real-time decadal forecasts suggest that the HMA will experience accelerated warming in 2025–2032, where the surface warming will increase by 0.98 °C (0.67 to 1.33 °C; 5 % to 95 % range) relative to the reference period 1991–2020, which is equivalent to 1.75 times the observed warming during 2016–2023. The decadal predictability originates from extratropical Pacific decadal variability modes, which modulate the convective heating in the tropical Pacific and influence HMA via the eastward-propagating atmospheric Kelvin waves. Accelerated warming in the coming decade will likely increase the shrinkage of the glacier volume over the HMA by 1.4 %. This change poses unprecedented challenges, including potential water scarcity, ecosystem disruption, and increased risk of natural disasters, to HMA and surrounding regions.

Riverine concentrations and export of dissolved silicon, and potential controls on nutrient stoichiometry, across the land–ocean continuum in Great Britain

Silicon (Si) is an essential nutrient element in freshwater and marine ecosystems, and its abundance relative to macro-nutrients (N, P) can impact phytoplankton communities in eutrophic rivers and estuaries. This study is the first national assessment examining (i) the primary sources (geological, biological, landcover) and controls (geomorphological, precipitation) on the transport of terrestrial dissolved silicon across Great Britain to the ocean, and (ii) the current extent and nature of its interactions with macro-nutrients in these catchments in relation to its potential impacts on phytoplankton community structure. It uses results from a year-long survey of 41 rivers along with historical data. Highest concentrations of dissolved Si (4–5.5 mg L-1) were found in rivers of the chalk- and sedimentary sandstone-based catchments of southern Great Britain and the hard sandstone catchments of Scotland. Catchment yield rates for dissolved Si varied between 0.2 and 2.6 t km−2 yr−1, with highest yields found in catchments with higher precipitation and runoff. Analysis of river N:P and dissolved Si:N ratios suggested that the sampled rivers were typically N enriched, and P limited with respect to dissolved Si. Molar dissolved Si:N ratios < 1, an indicator of river eutrophication, were associated with total nitrogen concentrations exceeding 1.8 mg L-1 or greater. The Indicator of Coastal Eutrophication index was used to assess the potential role of dissolved Si in the eutrophication of coastal waters. Negative values indicating limited eutrophication potential to non-siliceous algae were generally found, although some rivers had annual Indicator of Coastal Eutrophication index values exceeding 0, with values as high as 35 kg C km−2 day−1. In many eutrophic rivers, high dissolved Si concentrations derived from catchment lithology, kept the Indicator of Coastal Eutrophication index values below zero. Results have demonstrated that high N and P export have likely shifted most Great Britain rivers and coastal waters beyond the stoichiometric range where diatoms dominate production and into one where non-siliceous algae maybe increasingly present. Thus, future assessments of macro-nutrient management schemes, such as those involving wetlands should include dissolved Si routinely due to its stoichiometric importance.

The where and why of large wood occurrence in the Upper Mississippi and Illinois Rivers

AbstractLarge wood (LW) plays important geomorphic and ecological roles in rivers and is widely used as a restoration tool. Changes to floodplain land use and historical removal have altered wood dynamics in fluvial systems globally. We know little about the distribution and dynamics of LW in great rivers (approximately &gt;105 km2) like the Upper Mississippi and Illinois Rivers despite its ecosystem importance and use in restoration projects. We assessed LW occurrence data collected by the fisheries component of the Upper Mississippi River Restoration Program's Long Term Resource Monitoring element. We analysed 25 years of data collected across six reaches of the Upper Mississippi and Illinois Rivers that represented contrasting physiographic settings, and across four aquatic area types comprising gradients of hydrology, connectivity and geomorphology. We tested hypotheses on drivers of LW occurrence using generalised linear mixed effects models, where occurrence was predicted by reach‐ and local‐scale environmental variables. Occurrence varied significantly across reaches and aquatic area types. In general, wood occurred more frequently upriver and in side channels compared to other aquatic areas. Large wood was most strongly predicted systemically by reach identity but not local‐scale variables, underscoring the importance of broad‐scale physiographic gradients in defining hydrogeomorphic processes. Floodplain forests and shoreline revetment were consistently important predictors across reaches. Our findings show that the spatial variability of LW occurrence reflects the physical variability of the Upper Mississippi and Illinois Rivers. They also reveal the value in using geomorphic classifications as frameworks for understanding physical processes like LW dynamics because of their ability to contextualise site‐scale conditions. The baseline understanding of LW abundance across different hydrogeomorphic gradients and scales presented here can give insight into how to more effectively target restoration efforts in great rivers and contribute to a broader understanding of LW dynamics where such studies have been lacking.

Spatial-temporal variation of river ice coverage in the Yenisei river from 2002 to 2021

River ice is an essential component of the terrestrial cryosphere, which is sensitive to global and regional climate change. The Yenisei River provides the largest river inflow to the Arctic Ocean, heavily affected by the cold climate. Data on the ice cover in the Arctic great rivers are insufficient due to the absence of a river ice database with high spatiotemporal resolution. In this study, the daily river ice coverage (RIC, defined as the fraction of river ice pixels to river pixels in a grid cell) in the Yenisei River was estimated from 2002 to 2021 in a 12.5 × 12.5 km grid, by utilizing a cloud removal method for Moderate Resolution Imaging Spectroradiometer (MODIS) data. Based on Landsat imagery reference, the RIC correlations (Pearson’s R) were 0.77, 0.84, and 0.97 for three separate validation regions. Over the past 20 years, 82.8 % of the grid cells experienced a decreasing ice cover, with 21.9 % significant at the 0.05 level. The mean winter air temperature was the key predictor (R2 = 0.48, P < 0.01), better than the accumulated negative air temperature (R2 = 0.42, P < 0.01). The spatial distribution of winter RIC exhibited a latitudinal gradient (R2 = 0.64, P < 0.01). River ice responded to temperature variation in a non-linear way, depending on latitude, with high sensitivity in the southern part of the watershed. In Lake Baikal in the river basin, the distribution of ice cover was also affected by stream inflows. The results provide a comprehensive insight into the spatial–temporal variations of the Yenisei River and explore the key factor of changes in river ice, enhancing our ability to understand the response of Arctic great rivers to climate change.

Isotopic diversity and niche patterns reveal contrasting resource use among co-occurring non-native fishes within a flow-altered African river system

Classic and contemporary trophic ecology-based studies have shown that most non-native freshwater fish species (NNS) that integrate into novel environments have the potential to influence the recipient ecosystems’ structure and function. However, the interspecific trophic interactions amongst co-occurring NNS within invaded systems remain poorly studied. Here, we used carbon (δ13C) and nitrogen (δ15N) stable isotope analyses to examine general fish trophic diversity patterns (native and non-native fishes) and to explore trophic niche patterns amongst co-occurring NNS within a flow-modified river system, the Great Fish River (South Africa). The system was characterised by isotopic variation, which revealed spatial differences in trophic complexity from uninvaded headwater tributaries to invaded mainstem and downstream sections. Two of the invaded sections, the upper mainstem of the Great Fish River (UGFR) and the Koonap River, had low isotopic overlaps between NNS and the native fish assemblages. Furthermore, co-occurring NNS in these two invaded sections had variable isotopic niche sizes and low interspecific isotopic niche overlaps, suggesting the potential for trophic differentiation. By comparison, there was evidence of high resource use patterns among NNS within the lower mainstem section of the Great Fish River (LGFR), which likely reflected trophic plasticity. Overall, results of this study provided evidence of both trophic niche differentiation (UGFR and Koonap River) and niche overlap (LGFR) as probable mechanisms of co-occurrences of the non-native fishes within different invaded sections of the Great Fish River system, and underscores the difficulties associated with predicting their trophic impacts.

‘Past Those Green Temples’: The Eco-Humanist Poetics of Mary Oliver, Louise Glück, and Anne Carson

The preface for Mary Oliver’s poem ‘The River’, featured in her collection Dream Work (1986), cites an article by the New York Times: ‘In one day the Amazon discharges into the Atlantic the equivalent of New York City’s water supply for nine years.’(Dream Work 20). In the verses that follow this statistic, the poet (1935-2019) proposes a perspective that is at once human and river – merging the bodies of humanity and water in one. The poem’s speaker recalls her origins, wilfully ignoring the bureaucratic factoids of birthdate and place and defines themselves as ‘a grain / carried by the flood’ of a great, universal and unnamed river. This unnamed river, presumably the Amazon of the poem’s statistical prelude, carries the blueprint of the speaker’s history. It is also the place called ‘home’ by the speaker, a place remembered and yearned for. Throughout, the poem recalls a sense of wanting to belong and return to an unidentified and yet uniquely familiar river, or larger body of water. In a state of reverie, the speaker muses on how ‘the smell of mud and leaves returned to me / and in dreams I began to turn, / to sense the current’(20). The sensual borders of being human and being water merge completely here. Finally, after nostalgic remembrance, the speaker finds that it is ‘past those green temples’ where the final resting place is, where the body moves towards subconsciously, where home truly is.

Romanians and Bulgarians – Incidents at the Danube River Border (1890-1901)

On 2/14 September 1829, the Peace Treaty of Adrianople between the Tsarist Empire and the Ottoman Empire was concluded with important effects for the two Romanian countries, Moldavia and Wallachia. Their political development was regulated by a separate document, an integral part of the text of the Treaty. The separate Act confirmed the agreements made by the Tsarist Empire and the Ottoman Empire in the text of the Akkerman (White Citadel) Convention on 25 September/7 October 1826, on the election of the Romanian ruler, following the wish and consent expressed by the Sublime Porte. In addition to these political issues, important for the topic covered in this article were the provisions related to the protection of the borders, especially the right bank of the Danube and the islands close to the left bank of the great river that were in proximity to the Ottoman Empire. According to the Adrianople Treaty of 1829, the thalweg along the Danube was considered the border between Moldova and Wallachia on the entire common sector up to the confluence with the Prut River, agreement protected by the Sublime Porte. In 1830, after the Treaty of Adrianople, a commission composed of the delegates of Wallachia, Moldavia, the Tsarist Empire and the Ottoman Empire proceeded to delimiting the river border between the Ottoman Empire and the Romanian Countries by fixing the existing thalweg at that time. Obviously, natural phenomena contributed over time to its modification, so that, after the Congress of Berlin in 1878, when it was decided to trace the land border between the countries bordering the Danube, a series of incidents at the Romanian-Bulgarian river border occurred. In this context, it is highlighted the strategic and economic importance of the Danube.

Romanians and Bulgarians – Incidents at the Danube River Border (1890-1901)

On 2/14 September 1829, the Peace Treaty of Adrianople between the Tsarist Empire and the Ottoman Empire was concluded with important effects for the two Romanian countries, Moldavia and Wallachia. Their political development was regulated by a separate document, an integral part of the text of the Treaty. The separate Act confirmed the agreements made by the Tsarist Empire and the Ottoman Empire in the text of the Akkerman (White Citadel) Convention on 25 September/7 October 1826, on the election of the Romanian ruler, following the wish and consent expressed by the Sublime Porte. In addition to these political issues, important for the topic covered in this article were the provisions related to the protection of the borders, especially the right bank of the Danube and the islands close to the left bank of the great river that were in proximity to the Ottoman Empire. According to the Adrianople Treaty of 1829, the thalweg along the Danube was considered the border between Moldova and Wallachia on the entire common sector up to the confluence with the Prut River, agreement protected by the Sublime Porte. In 1830, after the Treaty of Adrianople, a commission composed of the delegates of Wallachia, Moldavia, the Tsarist Empire and the Ottoman Empire proceeded to delimiting the river border between the Ottoman Empire and the Romanian Countries by fixing the existing thalweg at that time. Obviously, natural phenomena contributed over time to its modification, so that, after the Congress of Berlin in 1878, when it was decided to trace the land border between the countries bordering the Danube, a series of incidents at the Romanian-Bulgarian river border occurred. In this context, it is highlighted the strategic and economic importance of the Danube.

Romanians and Bulgarians – Incidents at the Danube River Border (1890-1901)

On 2/14 September 1829, the Peace Treaty of Adrianople between the Tsarist Empire and the Ottoman Empire was concluded with important effects for the two Romanian countries, Moldavia and Wallachia. Their political development was regulated by a separate document, an integral part of the text of the Treaty. The separate Act confirmed the agreements made by the Tsarist Empire and the Ottoman Empire in the text of the Akkerman (White Citadel) Convention on 25 September/7 October 1826, on the election of the Romanian ruler, following the wish and consent expressed by the Sublime Porte. In addition to these political issues, important for the topic covered in this article were the provisions related to the protection of the borders, especially the right bank of the Danube and the islands close to the left bank of the great river that were in proximity to the Ottoman Empire. According to the Adrianople Treaty of 1829, the thalweg along the Danube was considered the border between Moldova and Wallachia on the entire common sector up to the confluence with the Prut River, agreement protected by the Sublime Porte. In 1830, after the Treaty of Adrianople, a commission composed of the delegates of Wallachia, Moldavia, the Tsarist Empire and the Ottoman Empire proceeded to delimiting the river border between the Ottoman Empire and the Romanian Countries by fixing the existing thalweg at that time. Obviously, natural phenomena contributed over time to its modification, so that, after the Congress of Berlin in 1878, when it was decided to trace the land border between the countries bordering the Danube, a series of incidents at the Romanian-Bulgarian river border occurred. In this context, it is highlighted the strategic and economic importance of the Danube.

Water Governance in Tanzania – A Synthesis of Legal and Institutional Frameworks for Groundwater Management in the Upper Great Ruaha River Catchment

The importance of groundwater resources in buffering the effects of climate change on water scarcity and security is highly acknowledged worldwide. However, groundwater development and use can only be sustainable with a more robust policy and institutional arrangements related to water governance. The purpose of this study was to analyse the legal framework of water resource development and management in order to contribute in identifying policy constraints to sustainable groundwater resource development and management in Tanzania. The paper used information from literature reviews and data collected through qualitative methods using a case study of Usangu Plains in the Upper Great Ruaha River Catchment in Tanzania. The findings reveal that water governance institutional frameworks are well structured to provide guidelines on how water as a basic human resource can be utilised and properly managed, but most importantly, these institutional arrangements place disproportionate emphasis on groundwater. Attaining sustainable groundwater development and use requires new disclosures and narratives in water policy and law, integrating both surface and groundwater resources. The weaknesses identified in groundwater governance need to be taken on Board once, the existing water institutional frameworks open to perfection for sustainable utilisation of groundwater resources

Assessment of Heavy Metal Contamination in Shrimp and Water from the Great Kwa River: Implications for Human Health and Aquatic Ecosystems

The aftermath of heavy metal pollution can be hazardous to humans, considering the level of consumption of shellfish in riverine areas - which is relatively high. There is a growing concern about the quality of aquatic food (e.g. periwinkle and shrimp) in several parts of the world. The determination of toxic elements in food has prompted studies on toxicological effects of heavy metals in foods. Due to man’s industrialization activities such as oil exploration, the levels of toxicants in marine environments have increased over the years. This study aimed at evaluating heavy metal contents (lead, cadmium, nickel, manganese, chromium and copper) in shrimp and water obtained from Great Kwa River, Calabar, Cross River State, Nigeria. Fresh shrimp and water samples were collected from the river in Calabar metropolis, Cross River State. In the sample preparation, the soft tissue (edible part) of the shrimps were extracted, dried in the oven (at 80°C) for 72hours then, after which the weights of the shrimps and water from each sampling point were measured. Digestion of the samples were carried out before an Atomic Absorption Spectrophotometer was used to determine the concentrations of the heavy metals. Graph pad Prism Version 7 was used for statistical analysis and Microsoft Excel Application. The results indicate contamination of both the shrimps and water from the Great Kwa River by some heavy metals, which also pose a health risk to aquatic ecosystem and humans. Among the heavy metals studied, chromium had the highest concentrations in both shrimps (30.07 ± 0.67ppm) and water (27.68 ± 0.34ppm). The heavy metals were found in higher concentrations in the shrimp than in water, except for manganese which had a significantly (p&lt;0.05) higher concentration in water (15.05 ± 0.67ppm as against 14.02 ± 0.93ppm in shrimp). Certain minerals have biological uses, but concentrations above recommended levels become detrimental to consumers. The levels of some of these heavy metals in this study, call for more investigation and regulation of their anthropogenic sources in order to reduce risk of public health issues.

The impact of physical geography factors on the division of Kurdish language – taking the dialect of Surchi tribe as example

The title of our research is about (The impact of physical geography factors on the division of Kurdish language – taking the dialect of Surchi tribe as example). In this study, we will try to highlight the physical geography factors which can divide a language into several dialects, there are similar factors that divided the Kurdish language into four main dialects, each of which is divided into several sub-dialects, we will also try to focus on a physical geography factor which is the Great Zab River in the territory of ​​the Surchi tribe, which has made the population belonging to the tribe on both sides of the river, although whose main language is Kurdish, their speech styles may differ in terms of language levels, and these distinctions are more noticed by linguists. In this research, we have done several field visits and interviews with villagers of some villages belonging to the Surchi tribe on both sides of the Great Zab River. After researching and interviewing in these areas, we decided to take two villages as samples of our research, each of which is different in terms of physical geography and speech styles. Zerav village is located on the bank of a river on the right side of the Great Zab, while Kalakin village is located on the left bank of the Great Zab. This study is divided into three main parts: First part concerns Kurdish Language and its dialects, second part is about physical geography factors on division of the Kurdish language, third part presents Surchi tribe, it describes the geographical boundaries of Surchi tribe, then analyzes the speech style of Surchi tribe in general and identifies the phonemes of both villages (Kalakin Sarchia) and (Zerav) in particular, then compare them with each other in terms of phonology.

Dissolved Major and Trace Elements in the Largest Eurasian Arctic Rivers: Ob, Yenisey, Lena, and Kolyma

In contrast to fairly good knowledge of dissolved carbon and major elements in great Arctic rivers, seasonally resolved concentrations of many trace elements remain poorly characterized, hindering assessment of the current status and possible future changes in the hydrochemistry of the Eurasian Arctic. To fill this gap, here we present results for a broad suite of trace elements in the largest rivers of the Russian Arctic (Ob, Yenisey, Lena, and Kolyma). For context, we also present results for major elements that are more routinely measured in these rivers. Water samples for this study were collected during an international campaign called PARTNERS from 2004 through 2006. A comparison of element concentrations obtained for Arctic rivers in this study with average concentrations in the world’s rivers shows that most elements in the Arctic rivers are similar to or significantly lower than the world average. The mineral content of the three greatest rivers (Ob, Yenisey, and Lena) varies within a narrow range (from 107 mg/L for Yenisey to 123 mg/L for Ob). The Kolyma’s mineral content is significantly lower (52.4 mg/L). Fluxes of all major and trace elements were calculated using average concentrations and average water discharge for the 2004–2006 period. Based on these flux estimates, specific export (i.e., t/km2/y) for most of the elements was greatest for the Lena, followed by the Yenisey, Ob, and Kolyma in decreasing order. Element pairwise correlation analysis identified several distinct groups of elements depending on their sources and relative mobility in the river water. There was a negative correlation between Fe and DOC concentration in the Ob River, which could be linked to different sources of these components in this river. The annual yields of major and trace elements calculated for each river were generally consistent with values assessed for other mid-size and small rivers of the Eurasian subarctic.

Global river economic belts can become more sustainable by considering economic and ecological processes

High-quality regional development requires coupling of socioeconomic and natural domains, but it remains unclear how to effectively integrate the regional economy with river basin ecosystems. Here we establish a developmental perspective of 65 river economic belts, formed through history along the main stems of the world’s great rivers, covering initial, developing, and developed stages. We find that river economic belts characterized by basin-based regional integration can substantially upgrade their eco-efficiency through the harmonization of enhanced regional economic growth and efficient utilization of basin resources, once key prerequisites (e.g., gross domestic product per capita, de-industrialization status, and human development index) are met for river economic belts entering the developed stage. Importantly, primary concerns such as resource stress, environmental pollution, and biodiversity loss are also inherently addressed. Under representative scenarios of regional development planning and climate change (2015–2050), the basin-based regional integration strategy would provide river economic belts with new opportunities and pathways towards sustainability in emerging regions worldwide.

Effects of Municipal Waste Discharge and its Re-Suspension on Water Quality in the Great Kwa River Estuary, Cross River State, Nigeria

Effects of Municipal Waste Discharge and Its Re-suspension on Water Quality in the Great Kwa River Estuary, Cross River State, Nigeria investigates the impact of municipal waste discharge and its re-suspension on water quality in the estuary. The research was conducted at two locations, Obufa Esuk, and Idundu, utilizing heavy metal analysis and Pollution Load Index (PLI) calculations during dry and wet seasons. Water samples were collected and analyzed using standard methods for heavy metal detection, including atomic absorption spectroscopy, while the PLI was calculated based on the concentration of pollutants relative to background levels. Results show that copper (Cu) and zinc (Zn) levels at both sites are within World Health Organization (WHO) safety limits. However, lead (Pb) and cadmium (Cd) concentrations are significantly high. At Obufa Esuk, cadmium reaches 0.76 mg/L in the dry season and 0.7 mg/L in the wet season, exceeding the WHO limit of 0.003 mg/L. Lead levels are elevated but below the WHO threshold of 0.01 mg/L. At Idundu, cadmium peaks at 0.85 mg/L in the dry season and 0.73 mg/L in the wet season, with lead concentrations also exceeding safe limits. These elevated metal levels are linked to severe pollution from municipal waste discharge and its re-suspension. The PLI values indicate moderate pollution at both sites, with Obufa Esuk showing values of 2.30 and 2.25, and Idundu showing 1.85 and 2.15. This pollution is associated with high turbidity and Total Dissolved Solids (TDS). The study highlights the urgent need for improved waste management practices, recommending upgrades to treatment facilities, stricter regulations, enhanced runoff, and erosion management, regular water quality monitoring, public awareness campaigns, and better stakeholder collaboration to protect water quality and public health in the Great Kwa River estuary.

Assessment of Quality of Water Resource from Great Ruaha River and Allied Water Sources Serving Domestic Purposes at Pawaga Division

This study intended to assess water quality from Ruaha River and allied water sources serving domestic purpose in Pawaga division. By using standard methods triplicate samples from sixteen (16) different sites were collected and analyzed for physicochemical parameters and bacteriological values. The conductivity of analysed samples ranged between 1 – 286 µS/cm which is lower than the TBS threshold 2,500 µS/cm. The TDS ranges between 107 – 2235.8 mg/L during the wet season and 49.0 – 2,616.3 mg/L during the dry season. The level of Na+ ranges between 0.2 – 104.4 mg/L during rainy season and 0.8 -119 mg/L during dry season. Nitrate levels ranges between 0.4 – 101.4 mg/L during rainy season and 0.3 – 107.9 mg/L during dry season. This may be contamination from fertilizers, municipal wastewaters, feedlots, septic systems in river water. Sulphate concentration ranges between 0.3 – 93.0 mg/L during rainy season and 3.7 – 98.9 during dry season. Sulphate can also be produced by bacterial or oxidizing action as in the oxidation of organo-sulphur compounds and the more common sinks are pyrite, gypsum, and sulphate reduction. The study concluded that, water supplied by Pawaga water supply must be treated to eliminate microbial, physical and chemical pollution prior to domestic water supplies. It recommended that Government should strengthen water intervention management and carry out intervention measures to improve water quality and reduce water pollution’s impact on human health. The control of water pollution can be done by increasing monitoring of wastewater disposal into rivers, carrying out an inventory and identifying water pollution sources.