Deterioration Of Water Quality Research Articles

Spatio-temporal dynamics of anthropogenic land-use pressures on temporarily closed estuaries in South Africa: a four-decade remote sensing analysis

Land-cover change is the leading cause of habitat loss globally. The extent of estuarine habitat loss and land-use pressures are understudied in South Africa, particularly in the numerically dominant temporarily closed estuaries. Remote sensing techniques are effective tools for monitoring estuarine habitat loss, and the type and intensity of anthropogenic influences that derive from land-use, such as water quality deterioration. This study quantified land-use/land-cover within and adjacent to 57 temporarily closed estuaries in KwaZulu-Natal, on the subtropical east coast of South Africa, to investigate spatio-temporal land-use trends over the past four decades. Urban and agricultural land-use pressures were high in the estuarine functional zone and adjacent ecotones (32.1% and 52.1% transformed, respectively). The rate of land-cover change has stabilised, following a decline in transformation over time due to the withdrawal of cultivation from some wetland areas. There was, however, evidence of land-use intensification between the 1980s and 2018 as former agricultural land was progressively developed for urban or peri-urban use, and sand mining was identified as an important local land-use. High intensity sand mining, continued urban expansion and the introduction of urban land-uses in rural areas will intensify local land-use pressures, leading to further declines in regional estuary health.

Hydrochemical insights into spatiotemporal characteristics of groundwater salinization and health risk assessment of fluoride in the south bank of Yellow River irrigation area, Northwest China.

The groundwater salinization problem in the south bank of the Yellow River irrigation area is severe, restricting the sustainability of groundwater resources. However, the groundwater salinization formation mechanism is unclear. Accordingly, this study analyzed the chemical characteristics and salinization mechanism of groundwater based on hydrochemical analyses (self-organizing maps, SOM), isotope analyses (δ18O and δD), and quantitative models (Rayleigh distillation model), as well as evaluating the potential health risks of fluoride. The results indicated that surface water and groundwater in the study area had high salinity and weak alkalinity, with the fluoride and total nitrogen (TN) content exceeding Grade III water standards. Additionally, only 42% of the water samples were suitable for drinking, with nitrogen sources being the main cause of water quality deterioration. Around half of the samples were unsuitable for irrigation. The spatial and temporal distribution of total dissolved solids (TDS) in the irrigation area was influenced by autumn irrigation. Overall, groundwater salinization was primarily attributed to evaporite dissolution, cation exchange, silicate weathering, and human inputs. Evaporation was not the main influencing factor. In addition, the non-carcinogenic risk of fluoride in the water body decreased as follows: infants > children > adult females > adult males. The results of this study deepen understanding of the relationship between changes in groundwater quality and the ecological environment in semi-arid inland areas, thereby promoting the rational utilization and scientific management of groundwater resources in the irrigation area.

Heavy metal(loid) contamination in forest fire affected soil and surface water: pollution indices and human health risk assessment.

Forest fires, whether natural or anthropogenic, release and mobilize heavy metal(loids) (HM). Following intense rainfall events, soil-bound HM are transported from soil to surface water through surface runoff, leading to water quality deterioration. Pollution and ecological risk indices are effective tools for assessing HM contamination. Most forest fire-affected soils and surface water exhibited a degree of contamination greater than 3 and 8 (high and moderate pollution), with associated high and extremely high ecological risks (165 and 2389, respectively). Pollution indices revealed that soils were highly contaminated with Ni, Cu, Cr, and Pb, while Ni, Cu, Hg, Cd, and As posed significant ecological risks. Surface water was heavily contaminated with Pb, Mn, Al, and Fe, with Ni and V contributing to extremely high ecological risks. This study highlights that trace HM also requires substantial removal efforts to make water potable, with removal efficiencies needed for Sb (94.49%), Be (85.83%), Ba (70.75%), V (68.19%), and Se (65.51%). Fire-affected surface water poses an elevated cancer risk to both children (0.18 and 4.5 × 10-3) and adults (0.39 and 1.53 × 10-3) through oral and dermal exposure, respectively. Children are more vulnerable to dermal cancer and noncancer risks compared to adults. Low-cost treatment methods, such as the application of immobilizing agents combined with compost, straw mulching, and seeding, can be implemented to control soil erosion in forest areas, thereby reducing the transport of soil-bound HM to surface water. These findings can aid government agencies in developing new soil and water quality standards and implementing effective treatment measures.

Leveraging historical datasets to quantify the recovery of an impaired stream entering Yellowstone National Park

Environmental impacts from surface mining can extend beyond the lifetime of mining operations, persist for decades prior to formal clean-up, and span multiple jurisdictional boundaries. Using a case study from Soda Butte Creek which enters Yellowstone National Park, we demonstrate how existing datasets and longitudinal studies can be integrated to document early stages of recovery following reclamation. Nearly three decades of previous studies provided a baseline for biological and water quality impairments from a former mill and tailings site. Direct comparisons of water quality data, macroinvertebrate community summaries, and fish abundance data from references reaches and common locations pre- and post-reclamation were used to quantify whether desired ecological benchmarks were met and characterize rates of recovery. Our results indicated that response times of water quality, macroinvertebrates, and fish to reclamation were relatively rapid and measured in years rather than decades. Specifically, concentrations of total metals below the former mill and tailings site were lower than pre-reclamation levels. Five years post reclamation (2015 to 2019), median total iron concentrations were just 3% of levels measured the decade (2000 to 2010) before reclamation began. Macroinvertebrate metrics (richness and abundance of sensitive groups) below the former mill and tailing sites were formerly a fraction of reference conditions. Post-reclamation, total taxa richness and stonefly abundance estimates at the formerly impaired site were equal to the mean multi-reach proportional estimates for other mainstem reference sites. Lessons learned from Soda Butte Creek could be used to inform and support other data-driven assessment work.

Estimation of non-point source of pollution loads in the River Song, a tributary of River Ganga, India.

The Himalayan rivers are particularly vulnerable to regional climate changes and anthropogenic influences, which can significantly alter both water quality and quantity, jeopardizing the fragile river ecosystems. This study investigates the hydrochemical characteristics of the Song River, a tributary of River Ganga focusing on non-point source (NPS) pollution, during the period June 2022 to November 2023. Monitoring of river discharge was carried out water samples were collected weekly during the monsoon (June to September), bi-weekly in the post-monsoon (October & November), and monthly during lean periods (December-May) from three monitoring stations. The study revealed that Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) eventually exceeded the criteria limits (3mg/L for BOD and 10mg/L for COD) prescribed by the Central Pollution Control Board (CPCB). The chemical composition of the river water at the monitoring stations revealed Ca2+and Mg2+ as the dominant cations, while HCO3⁻ and SO42⁻ were identified as the major anions. Gibbs plot suggesting the dominance of rock weathering as the major natural controlling mechanism of chemical composition in the basin. Carbonation and sulphide oxidation are two proton-producing reactions controlling the chemical weathering processes. C-ratio plot suggested that dominance of carbonate dissolution in the tributary Suswa, while Song River showed dominance of sulphide oxidation, particularly in its upstream region. Spatial and temporal analysis identified nutrient pollution (NO₃⁻, NH₄⁺, PO₄3⁻), organic loads (BOD, COD), and other parameters (TSS, Cl⁻) as key contributors to water quality deterioration at the monitoring stations. A chemical mass balance (CMB) approach based on mass conservation has been applied for estimating the NPS pollution loads on the Song River. CMB calculations carried out for major cations such as (Na+, K+, Ca2+, Mg2+, and NH4+) and major anions (Cl⁻, SO42⁻, HCO3⁻, NO3⁻, and PO43⁻) across a 21km stretch of the river, encompassing approximately 305 sq. km. and observed that the contribution of uncharacterised load was maximum in dry season and minimum during monsoon season. Seasonal variations in ion concentration and flux were strongly correlated with hydrological processes, highlighting the need for comprehensive monitoring and management of NPS pollution in the Song River to safeguard its water quality and downstream impacts on the Ganga River system.

Response mechanisms of eukaryotic plankton community structure to complex environmental conditions in semi-arid river basins, China.

Response mechanisms of eukaryotic plankton community structure to complex environmental conditions in semi-arid river basins, China.

An integrated approach to coupled nutrient and microbial source tracking in an agricultural watershed.

An integrated approach to coupled nutrient and microbial source tracking in an agricultural watershed.

Reorienting urban stream management to focus on equitable delivery of benefits

Urban streams are often managed in ways that contribute to societal inequities. Members of marginalized groups are frequently exposed to elevated flood risk and impaired water quality, with reduced access to essential water infrastructure and greenspace within stream corridors. The freshwater science research community has traditionally argued for stream management that improves ecological integrity, which can have the unintended consequence of steering investments away from the most degraded streams, which are often in low-income neighborhoods. We argue that it is time to reorient municipal stream management programs towards the objective of equitable delivery of benefits, which can take many forms, and to de-emphasize the goal of restoring streams to the pre-development ecological condition. To meet the objective of equitable delivery of benefits, municipalities will need to establish systems of collaborative governance, in which community organizations are empowered to participate as equal partners in urban stream management decision-making. We recognize the many practical challenges municipalities face in making these transitions, which will vary by country and region. Here, we identify some opportunities and highlight case studies illustrating how some communities are taking steps toward more equitable urban stream management.

Influence of habitat structures on fish abundances and diversity: comparing mainstream and tributary communities in the urban uMsunduze Catchment, KwaZulu-Natal, South Africa

Various factors drive the decline of freshwater vertebrate biodiversity. These include changing landscape and urbanisation, introduced invasive species, altered habitat, water quality deterioration, instream barriers, and climate change. In the present study, we evaluated the impact of different habitat features on the fish assemblages in an urban river using catch per unit effort (CPUE) as a proxy for fish assemblage per site and season. We sampled 17 main sites and 21 ad-hoc sites in the uMsunduze Catchment in Pietermaritzburg, uMgungundlovu District, KwaZulu-Natal, South Africa, during 2022–2023. We collected data using an electro-shocker, fyke nets, and gill nets, and we also recorded and calculated habitat features such as substrate types, hydraulic biotopes, in-situ water quality, ecohydraulics, average depth, and velocity. We used Generalised Linear Models to determine the habitat features driving fish communities. We calculated the Shannon-Weiner and Pielou diversity indices to compare between rivers. We used the Fish Response Assessment Index (FRAI) tool to understand each site’s ecological integrity per season. Our results indicated that various features, including substrate (mud, sand, gravel), fast intermediate and fast deep ecohydraulics, electrical conductivity, habitat (glide, pool), and average velocity significantly impacted the CPUE of fish. There was no variation in diversity indices between tributaries, but there was a significant difference in fish diversity between the uMsunduze mainstream and its tributaries. The FRAI scores showed great deterioration in the system’s ecological health, and most sites, especially the mainstream sites, were critically or extremely modified. We suggest that the relevant authorities take action to mitigate the pressures compromising the uMsunduze Catchment’s ecological integrity. There is an urgent need for conservation measures for the two “near threatened” species, Enteromius gurneyi and Amphilius natalensis, the former now extirpated as per our study.

Impact of land use change on the urban wetlands of the Imphal Valley in northeast India: an analysis of dying habitats of the endangered Manipuri pony-the original ponies of modern polo.

Since c. 3100 BC, the modern game of polo was played as 'Sagol Kangjei' in the ancient Kingdom of Manipur, India. Today, 'Sagol' or Manipur pony is an 'Endangered' pony breed. As per FAO population estimate, the breed has 994 individuals. The rampant destruction of natural habitats, mainly the urban wetlands in the Imphal Valley, has caused severe decline in the population of the indigenous breed. Therefore, as a part of conservation research, detailed encroachment status and impact of land use change on water quality of the urban wetlands in the Imphal Valley, i.e. Lamphel and Heingang pats, were assessed during 2022-2023. The land use/land cover analysis of the last three decades, viz. between 1988 and 2023, showed that the urban wetlands have lost 26.38 and 64.36% of its areas to human encroachment in the form of built-up or agricultural and pisciculture farms. The wetlands size got reduced by 132.3ha for Lamphel pat and 76.8ha for Heingang pat, respectively. Moreover, vegetation cover of the wetlands got reduced by 50.73% for Lamphel pat and 12.01% for Heingang pat, thereby forcing the pony breed to move from natural habitats. As a result, majority of pony populations today are found sheltering on busy roads of the Imphal urban region. Furthermore, the land use change has caused severe deterioration of wetland water quality. The Water Quality Index (WQI) for most of the sampling locations have WQI values in poor and unsuitable category, which unfortunately is the only source of water for the pony population in their habitat. Moreover, wetland vegetation or food plants of pony are exposed to high sodium percentage, sodium adsorption ratio, magnesium hazard and Kelly's ratio stress, which is injurious. As such, the endangered pony's habitats, i.e. urban wetlands, need effective long-term conservation and management plan that will restore both the ecosystem and the threatened pony breed populations.

A 150-year river water quality record shows reductions in phosphorus loads but not in algal growth potential

Eutrophication and proliferation of nuisance and harmful algal blooms are a major cause of water-quality impairment globally. Here, we analyze the world’s longest continuous (150-year) river water-quality dataset for the River Thames, U.K. (including biological oxygen demand, chloride, phosphorus and silica), to explore the impacts of urbanization, wastewater discharges and agricultural intensification. Over the last 40 years, improvements in wastewater treatment and agricultural management have reduced phosphorus loads by ~80%. However, this has been insufficient to curtail river algal blooms because nutrient concentrations remain above limiting levels. Over the last 50–60 years, rising water temperatures have increased the number of days with water temperatures favourable for diatom blooms in March-April and for cyanobacterial growth in July-August. These results highlight the challenges of eutrophication management in a warming climate and a strategic need to redouble efforts in further reducing nutrient emissions to control nuisance and increasingly harmful algal blooms.

Environmental risks of the third re-purposing of the Haber-Bosch reaction

Abstract The Haber-Bosch reaction, using energy to convert nitrogen gas into ammonia, is now being repurposed, fueled by renewable energy, to produce green ammonia. Green ammonia then becomes the carrier of hydrogen energy to fuel a range of processes, including the mobility of vessels and automobiles. Yet, the massive production of ammonia produced by the Haber-Bosch reaction to yield synthetic fertilizer applied to agricultural soils resulted in a major deterioration of water quality and the proliferation of dead zones in freshwater and coastal ecosystems. The combustion of ammonia results in reactive nitrogen species, such as NOx, which is also a potent green-house gas. To ensure that the green ammonia revolution delivers the environmental benefits it is designed to provide it is essential that policy regulations to avoid leakage of ammonia and reactive nitrogen forms to the environment precede its deployment at scale. New technologies are being proposed to further convert these products into inert N2, achieving circularity in the production and use of green ammonia, which is essential to avoid unintended environmental impacts.

Second Phase Study of Groundwater Quality in Kushalgarh Block Villages, Banswara District, Rajasthan

Water is crucial as it profoundly affects humans, wildlife, and aquatic life. The quality of water hinges on its composition, physical properties, and organic attributes. The rapid expansion of industrialization and increased use of chemical pesticides in agriculture have significantly contributed to the deterioration of water quality through contamination. The consumption of this polluted water has led to waterborne infections in the human population. In the current study, the quality parameters of water in the Kushalgarh block have been assessed. The assessment of water quality parameters in the Kushalgarh block indicates that all measured parameters remain within permissible limits. Despite concerns over industrialization and agricultural pesticide use, the study found no significant deviation in physical, chemical, or organic attributes of the water. These findings suggest that, while regular monitoring is essential, the current water quality poses no immediate health risks to humans or aquatic life.

LoRaBB: An Algorithm for Parameter Selection in LoRa-Based Communication for the Amazon Rainforest.

The interference of human activities in water bodies has contributed to a deterioration in water quality. With the advancement of the Internet of Things (IoT), aided by transmission technologies such as LoRa (Long Range), low-cost solutions have emerged for long-distance environment monitoring scenarios. One key challenge in such IoT-based systems is selecting LoRa transmission parameters to ensure efficient data exchange among nodes, adapting to varying network conditions. Well-known strategies adapt transmission parameters according to network context through information exchange among nodes and LoRa gateway(s). In this work, we introduce a novel LoRa parameter selection algorithm by incorporating three major LoRa metrics (RSSI, SNR, and PDR) and conducting a comprehensive characterization and validation in the forest environment to build a set of reference values of transmission quality, which are employed in a binary search methodology, utilizing the R-array, representing the transmission quality according to LoRa parameters. The experimental results indicate that the proposed algorithm achieves a 16.20% reduction in Time on Air (ToA). Furthermore, our algorithm optimized the transmission power (TP) selection, achieving at least 38% lower energy consumption than ADR TP parameters. These results highlight that our proposed algorithm can enhance the transmissions in a rainforest environment.

A machine learning model for detecting and quantifying tropical cyclone related disturbance and recovery in estuaries

Tropical cyclones have a significant impact on estuaries, resulting in deteriorating water quality, changes in phytoplankton productivity, as well as scouring and physical harm to mangroves and other vegetation. Furthermore, they have the potential to impede, pause, or even reverse ecosystem restoration and management efforts. As such, it is crucial to devise methods for detecting and measuring the severity of estuarine disturbances caused by tropical cyclones. Several statistical methods have been proposed in the past to detect and quantify disturbances, with varying levels of complexity and accuracy. Recent advancements in data collection and the quality of high-frequency data have opened up the opportunity to employ machine learning models for assessing the impact of tropical cyclones on ecosystems. This study develops a new machine learning-based model for detecting disturbances within estuaries, assessing their severity, and determining the recovery time, primarily focusing on disruptions to estuarine water quality. A Long Short-Term Memory (LSTM)-based deep learning model is developed to detect disturbances and quantify their severity while a Gaussian filter-based algorithm is developed to assess recovery time. The research utilizes data from NOAA’s National Estuarine Research Reserve System for training and validating the model. The model demonstrates an ability to distinguish between disturbances in water quality caused by tropical cyclones and those resulting from natural variability. It also assesses the extent of the disruption and the time for the estuary to revert to its pre-event state. Detecting and quantifying disturbances, as well as estimating recovery time in estuaries due to tropical cyclones, represent the initial steps in the development of predictive disturbance models. Detecting and quantifying disturbance can also aid stakeholders in comprehending the severity of tropical cyclones’ impacts on aquatic systems, allowing for the development of suitable interventions. The developed model can be applied to detect and quantify anomalies in any time series data, making it useful in various other fields.

Stream pathogenic bacteria levels rebound post-population control of wild pigs.

The range and density of one of North America's most destructive and invasive mammalian species, wild pigs (Sus scrofa), has expanded rapidly over the past several decades. Alongside this growth, their fecal contamination of surface waters has impaired water quality through significantly increased levels of pathogenic bacteria, raising concerns over the potential for zoonotic disease transmission. Significant remediation of these water quality impacts has been shown as a result of reductions in wild pig populations due to control efforts; however, the duration of these remediation effects as populations rebound remains unclear. Our study sought to determine the longevity of water quality remediation resulting from wild pig population control efforts. We found that median concentrations of Escherichia coli and fecal coliform (CFU/100mL) increased by 746% and 159% in the year following the conclusion of removal efforts, resulting in median concentrations of 79% and 159% greater than those observed prior. We also found increased public health risk, with samples exceeding E. coli and fecal coliform guidelines 10% and 12% more often than pre-removal, respectively. While further research into wild pig population dynamics and fecal contamination is necessary, we conclude that ongoing population control efforts may be necessary to remediate water quality impacts and public health risks associated with invasive wild pigs.

Distinguishing abiotic corrosion from two types of microbiologically influenced corrosion (MIC) using a new electrochemical biofilm/MIC test kit.

Distinguishing abiotic corrosion from two types of microbiologically influenced corrosion (MIC) using a new electrochemical biofilm/MIC test kit.

Multidrug-resistant ESBL E. coli in urban surface waters and public health implications: A Case Study from Goranchatbari, Dhaka.

Multidrug-resistant ESBL E. coli in urban surface waters and public health implications: A Case Study from Goranchatbari, Dhaka.

Influence of iron-modified biochar on phosphate transport and deposition in saturated porous media under varying pH, ionic strength, and biochar dosage.

Influence of iron-modified biochar on phosphate transport and deposition in saturated porous media under varying pH, ionic strength, and biochar dosage.

Groundwater Vulnerability to Seawater Intrusion in Parangtritis Beach, Yogyakarta Special Province, Indonesia

Abstract The consequences of increased tourism, population growth, and agricultural activities on groundwater resources are becoming increasingly concerning. The tourism industry in the Parangtritis Tourism Area has been expanding, leading to a rise in the number of hotels and visitors. This growth, along with the expanding population and the demand for groundwater in agriculture, has contributed to a reduction in groundwater reserves. Overexploitation of groundwater can result in several adverse effects, such as declining water tables and deteriorating water quality due to seawater intrusion. Seawater intrusion in coastal areas poses a serious threat, potentially hindering economic development, endangering local cultures, and contaminating groundwater sources. This study is critical as it aims to identify the geological and hydrogeological conditions and assess areas at risk of seawater intrusion in the study area. The research involved observing surface geological conditions, mapping hydrogeology, and applying the GALDIT method to assess the vulnerability to seawater intrusion. The findings reveal diverse lithology in the study area, including fine sand, coarse sand, sandy clay, floatstone, wackestone, andesite, and andesite breccia. Observations from 80 dug wells or boreholes indicated that groundwater use in the study area is limited to an unconfined aquifer with a thickness of up to 101 meters. The GALDIT index results show that the Parangtritis tourism area has a moderate to very high vulnerability to seawater intrusion. Areas with very high vulnerability are primarily concentrated in coastal zones with extensive groundwater usage, covering 4.04% of the total study area. Additionally, high vulnerability areas cover 11.23% of the total research area, characterized by high hydraulic conductivity values in aquifers and dominated by settlements and agricultural land use.