Water Quality Degradation Research Articles

Removal of organic micropollutants from water by adsorption on thermo-plasma expanded graphite encapsulated into calcium alginate

Nowadays, public concern is focused on the degradation of water quality. For this reason, the development of innovative technologies for water treatment in view of (micro)pollutant removal is important. Indeed, organic (micro)pollutants, such as pharmaceuticals, herbicides, pesticides and plasticizers at concentration levels of μg L−1 or even ng L−1 are hardly removed during conventional wastewater treatment. In view of this, thermo-plasma expanded graphite, a light-weight innovative material in the form of a powder, was encapsulated into calcium alginate to obtain a granular form useful as filtration and adsorption material for removal of different pollutants. The produced material was used to remove atrazine, bisphenol-A, 17-α-ethinylestradiol and carbamazepine (at concentration levels of 125, 250 and 500 µg L−1) by top-down filtration. The effect of flow rate, bed depth and adsorbent composition was evaluated based on breakthrough curves. The experimental data was analysed with the Adams-Bohart model in view of scale-up. Under optimal conditions, removal and adsorption capacity of respectively about 21%, 21%, 38%,42%, 43 µg g−1, 44 µg g−1, 37 µg g−1 and 87 µg g−1 were obtained for atrazine, bisphenol, 17-α ethinylestradiol and carbamazepine when using 0.12 g of thermo-plasma expanded graphite to treat 200 mL at 500 µg L−1 (for each compound) of solution obtaining at contact time of 20 min. The granular form of TPEG obtained (GTPEG) by entrapping in calcium alginate results to have a good adsorbent property for the removal of carbamazepine, atrazine, bisphenol A and 17-α ethinylestradiol from water at concentration levels between 250 and 500 μg L−1. Promising results confirm the adsorbent properties of TPEG and push-up us to investigate on its application and improve of its performance by evaluating different entrapping materials.

Identifying the critical lakeshore zone to optimize landscape factors for improved lake water quality in a semi-arid region of Northeastern China

The degradation of water quality and decline in purification capacity of lakeshore zones due to anthropogenic activities and climate change is a growing concern in China. The identification of the critical width of the lakeshore zone remains a challenge due to natural geographic features and pollutant types, that is why a general identification approach has yet to be developed. To facilitate the planning of lakeshore restoration plans, it becomes necessary to conduct studies focusing on the development of relationships between water quality and landscape factors within the lakeshore zone in different regions. In this study, spatio-temporal patterns of water quality of 49 lakes in Western Jilin Province, China, were determined through field monitoring from 2015 to 2019. Multivariate statistical methods were applied to quantitatively identify the relationships between lakes water quality and landscape factors within lakeshore zones of different widths. The results indicated that nitrogen (N) contributed more to eutrophication, while fluoride concentrations were found to be abnormally high. Furthermore, the width of the lakeshore zone was found to have a significant impact on water quality, with a critical width of 150 m having the greatest effect. Cropland and saline land explained almost 50% of the water quality variability throughout different seasons. The results also revealed that dual control of N and phosphorus (P) will be required to prevent eutrophication in the study area. Agricultural activities and severe soil salinization were identified as the main causes of diffuse pollution. The establishment of a width threshold identification framework for lakeshore zones is not only of great significance for development of scientific and acceptable restoration plans for lakeshore vegetation filters in ecologically vulnerable areas of western Jilin, but should also provide an effective and user-friendly tool for implementing diffuse pollution control.

Stable isotopes reveal organic nitrogen pollution and cycling from point and non-point sources in a heavily cultivated (agricultural) Mediterranean river basin

The Pinios River Basin (PRB) is the most intensively cultivated area in Greece, which hosts numerous industries and other anthropogenic activities. The analysis of water samples collected monthly for ∼1 ½ years in eight monitoring sites in the PRB revealed nitrate pollution of organic origin extending from upstream to downstream and occurring throughout the year, masking the signal from the application of synthetic fertilizers. Nitrate concentrations reached up to 3.6 mg/l as NO3−-N, without exceeding the drinking water threshold of ∼11.0 mg/l (as NO3−-N). However, the water quality status was “poor” or “bad” in ∼50 % of the samples based on a local index, which considers the potential impact of nitrate on aquatic biological communities. The δ15Ν-ΝΟ3− and δ18O-NO3− values ranged from +4.4 ‰ to +20.3 ‰ and from −0.5 ‰ to +14.4 ‰, respectively. The application of a Bayesian model showed that the proportional contribution of organic pollution from industries, animal breeding facilities and manure fertilizers exceeded 70 % in most river sites with an overall uncertainty of ∼0.3 (UI90 index). The δ18O-NO3− and its relationship with δ18O-H2O revealed N-cycling and mixing processes, which were difficult to identify apart from the uptake of nutrients by phytoplankton during the growing season and metabolic activities. The strong correlation of δ15Ν-ΝΟ3− values with a Land Use Index (LUI) and a Point Source Index (PSI) highlighted not only the role of non-point nitrate sources but also of point sources of nitrate pollution on water quality degradation, which are usually overlooked. The nitrification of organic wastes is the dominant nitrate source in most rivers in Europe. The systematic monitoring of rivers for nitrate isotopes will help improve the understanding of N-cycling and the impact of these pollutants on ecosystems and better inform policies for protection measures so to achieve good ecological status.

Studies on Vibrio campbellii as a newly emerging pathogen affecting cultured seabream (Sparus aurata) in Egypt

Aquaculture has become a crucial solution for addressing food scarcity worldwide, including Egypt. However, the intensification of aquaculture practices has led to water quality degradation and the emergence of new fish diseases, such as vibriosis. This study aimed to investigate the molecular typing, prevalence, pathogenicity, and environmental risk factors associated with Vibrio campbellii (V. campbellii) in cultured seabream. A total of 160 gilthead seabream, Sparus aurata (40 fish/season), along with 48 water samples (n = 12/season) were collected randomly and seasonally from private fish farms in the Suez Canal area over the course of a year for laboratory examinations. Clinical and postmortem inspections revealed characteristic signs and lesions similar to those observed in well-known vibrios infections. Bacteriological tests revealed the presence of V. campbellii strains in various internal organs. The isolated bacteria were identified morphologically, biochemically, and molecularly by targeting the 16S rRNA conserved gene. Histopathological examination was performed, providing insights into pathogen-induced tissue damage and septicemic disease progression. The prevalence of V. campbellii showed variable patterns across seasons, with higher proportions of cases in the summer. To examine the diagnostic performance of several water quality measures, the Receiver Operating Characteristic (ROC) curve analysis was performed. The results showed various levels of predictive performance for the outcome variable V. campbellii, with ammonia serving as a significant predictor for the variable of interest. The challenge results indicated a 100% survival rate in the controls, whereas the challenged group exhibited a mortality number of 6.00 ± 0.58, resulting in a survival rate of 70.00 ± 2.89%. The current study emphasizes how crucial it is to take into account seasonal parameters to comprehend the prevalence and seriousness of vibriosis in mariculture. The findings add to a better understanding of the impact of water quality on fish disease emergence and can benefit the creation of appropriate management measures to ensure aquaculture populations’ health and well-being.

Predicting cyanobacteria abundance with Bayesian zero-inflated models

Abstract Cyanobacterial blooms are a persistent concern to water management and treatment, with blooms potentially causing the release of toxins and degrading water quality. However, previous models have not considered the zero inflation of cyanobacteria count data. Typically, a relatively large proportion of measured count data are zeros or non-detects of cyanobacteria, representing either no cyanobacteria was present or the cell number was too low to be detected. Commonly used Poisson and negative binomial models for count data underestimate the probability of zero data, making these models less reliable. This study proposes a Bayesian approach to fit the cyanobacteria abundance data with mixture models that handle zero-inflated data. Predictor variables considered included weather and water quality measures that can easily be obtained day-to-day. The optimal model (zero-inflated negative binomial) was used to predict cyanobacteria alert levels on a separate test set. The ability to predict narrow alert levels was limited, however, 76% accuracy was achieved in predicting cyanobacteria counts above or below 1,000 cells/mL. Parameter estimates were highly variable and demonstrated that complex and uncertain factors influence cyanobacteria count predictions. The modelling approach can be applied to a wide range of environmental problems where zero-inflated data is common.

Wildfire impact on disinfection byproduct precursor loading in mountain streams and rivers

We investigated short (first post-fire precipitation)- and long-term (11-month) impacts of the Caldor and Mosquito Fires (2021 and 2022) on water quality, dissolved organic matter, and disinfection byproduct (DBP) precursors in burned and adjacent unburned watersheds. Both burned watersheds experienced water quality degradation compared to their paired unburned watersheds, including increases in dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and DBP precursors from precipitation events. DBP precursor concentrations during storm events were greater in the Caldor Fire's burned watershed than in the unburned watershed; precursors of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and haloacetamides (HAMs) were 533 µg/L, 1,231 µg/L, 64 and 58 µg/L greater. The burned watershed of the Mosquito Fire also had greater median concentrations of THM (44 µg/L), HAA (37 µg/L), HAN (7 µg/L), and HAM (13 µg/L) precursors compared to the unburned watershed during a storm immediately following the fire. Initial flushes from both burned watersheds formed greater concentrations of more toxic DBPs, such as HANs and HAMs. The Caldor Fire burn area experienced a rain-on-snow event shortly after the fire which produced the greatest degradation of water quality of all seasons/precipitation events/watersheds studied. Over the long term, statistical analysis revealed that DOC and DON values in the burned watershed of the Caldor Fire remained higher than the unburned control (0.98 mg C/L and 0.028 mg N/L, respectively). These short and long-term findings indicate that wildfires present potential treatment challenges for public water systems outside of the two studied here.

Differences in pathogenic community assembly processes and their interactions with bacterial communities in river and lake ecosystems

Pathogenic bacterial infections caused by water quality degradation are one of the most widespread environmental problems. Clarifying the structure of pathogens and their assembly mechanisms in lake ecosystems is vital to prevent the infestation of waterborne pathogens and maintain human health. However, the composition and assembly mechanisms of pathogenic bacterial communities in river and lake ecosystems are still poorly understood. In this study, we collected 17 water and 17 sediment samples from Lake Chaohu and its 11 inflow rivers. Sequencing of 16S rRNA genes was used to study bacterial pathogen communities. The results of the study showed that there was a significant difference (P < 0.05) in the composition of the pathogen community between riverine and lake habitats. Acinetobacter (36.49%) was the dominant bacterium in the river, whereas Flavobacterium (21.6%) was the most abundant bacterium in the lake. Deterministic processes (i.e., environmental filtering and species interaction) drove the assembly of pathogenic bacterial communities in the lake habitat, while stochastic processes shaped river pathogenic bacterial communities. Spearman correlation analysis showed that the α-diversity of bacterial communities was linearly and negatively linked to the relative abundance of pathogens. Having a higher bacterial community diversity had a suppressive effect on pathogen abundance. In addition, co-occurrence network analysis showed that bacterial communities were tightly linked to pathogenic bacteria. Pseudomonas aeruginosa and Salmonella enterica were identified as keystone species in an inflow water sampling network (W_FR), reducing the complexity of the network. These results provide a reference for assessments of water quality safety and pathogenic bacteria posing risks to human health in large freshwater lakes.

A Physical Perspective of Recurrent Water Quality Degradation: A Case Study in the Jiangsu Coastal Waters, China

AbstractEstuarine‐coastal systems receive pollutants from various sources at an alarming rate. Some systems are extremely susceptible to terrestrial input, as a relatively small amount of pollutant loading induces lasting water quality degradation. The Jiangsu coastal waters (JCWs), located in the southwestern Yellow Sea, are such areas that lack large river discharge but suffer from recurrent eutrophication recently. We hypothesize that the low flushing efficiency in the JCWs largely accounted for the susceptibility to coastal pollution. To test it, transit time (TT) and pollutant flushing rates in the JCWs were estimated under various scenarios using a validated three‐dimensional hydrodynamic model. Results show that TT in many inshore waters of the JCWs and the northern radial sand ridges is &gt;240 days, which are consistent with the observed frequently eutrophic areas. The JCWs are better flushed and thus less eutrophic in summer, as a consequence of the stronger tidal residual coastal circulation. The baroclinic pressure gradient, modulated by the formation and destruction of thermal stratification in offshore waters, poses a dominant control on the seasonal variations of the coastal circulation and flushing rates, while wind effects are secondary. River‐borne pollutants from the Yangtze and Jiangsu local rivers are shown to primarily affect regions south and north of 32.5°N, respectively. Our study interprets the vulnerability of the JCWs to pollutant enrichment from a physical perspective and finds the flushing efficiency to be a good indicator of eutrophication, providing references for environmental managers of local and global estuarine‐coastal systems with recurrent pollution.

Pollution source identification of nitrogen and phosphorus in the lower West Main Canal, the Ganfu Plain irrigation district (South China).

The degradation of surface water quality has been a widespread concern around the world. However, irrigation canal water does not attract much attention although it is important to agriculture and population. In this study, a 5-year water quality monitoring of surface water was conducted in the lower West Main Canal of the Ganfu Plain irrigation district to identify the levels and pollution sources of nitrogen and phosphorus.Over 75% of samples had total phosphorus (TP) concentrations of > 0.02mg/L, and all samples had total nitrogen (TN) concentrations of > 0.2mg/L, indicating a risk of eutrophication. The concentrations of NO3--N and NH4+-N averagely occupied 57% and 18% of TN, respectively. PCA analysis showed that phosphorus and nitrogen in canal water were associated with meteorological factors, urban life and surface runoff, agricultural cultivation, livestock-poultry breeding, and water-sediment interaction in the wet season, whereas they were affected by meteorological factors, industrial effluent, urban domestic sewage, and livestock-poultry breeding in the dry season. Absolute principal component score-multiple linear regression (APCS-MLR) model results revealed that (1) agricultural cultivation plus livestock-poultry breeding contributed 43.2% of TP in canal water in the wet season, while livestock-poultry breeding contributed 52.9% in the dry season, and (2) domestic sewage plus surface runoff contributed 29.4% of TN in the wet season, while livestock-poultry breeding contributed 45.9% in the dry season. The unidentified sources had significant contributions of > 20% for almost all variables. So further investigations are required for determining unidentified sources, and anthropogenic pollution control is imperative for canal water quality protection.

EVALUATING NANDINI RIVER WATER QUALITY: A SYSTEMATIC REVIEW OF PHYSICOCHEMICAL STUDIES

The quality of water is described to be the condition of the water, which includes the three basic forms of physical, chemical, and biological notions. Salinity, turbidity, the amount of dissolved oxygen and carbon dioxide, and microorganisms, herbicides, and pesticides along with the presence of heavy metals edit reminds to have a direct effect on the water quality. Because the universal solvent is a major factor affecting the lives of the humongous population of people, recognition of the quality of water is significantly important. Due to the fact that the presence of contaminants in water can directly lead to health issues such as reproductive problems, different kinds of neurological disorders, and gastrointestinal diseases, it is of vehement importance to understand the water quality. Nandini River flows through the Nashik city of Maharashtraand it is the tributary of the river Godavari which is is a vital source of water for the people of the Nashik region.Travelling from the heart of Nashik the river Nandini is faced with several issues related to its degrading water quality. Hence, the study sheds light onto the quality of water of the Nandini river, in terms of Physicochemical Studies.

Guiding the landscape patterns evolution is the key to mitigating river water quality degradation

Consensus has emerged that landscape pattern evolution significantly impacts the river environment. However, there remains unclear how the landscape pattern evolves possible to achieve a balance between land resource use and water conservation. Thus, simulating future landscape patterns under different scenarios to predict river eutrophication level is critical to propose targeted landscape planning programs and alleviate river water quality degradation. Here, we coupled five water quality parameters (TOC, TN, NO3−-N, NH4+-N, TP), collected from October 2020 to September 2021, to construct the river eutrophication index (EI) to assess river water quality. Meanwhile, based on redundancy analysis, patch-generating land use simulation model, and stepwise multiple linear regression model comprehensively analyze the Fengyu River watershed landscape patterns evolution and their impact on river eutrophication. Results indicated that current rivers reach eutrophic levels, and EI reaches 40.7. The landscape patterns explain 88.2 % of river eutrophication variation, while the LPI_Con metric is critical and individually explained 21.5 %. Furthermore, eutrophication in the watershed will increase in 2040 under the natural development (ND) scenario, and the EI will reach 44.4. In contrast, farmland protection (FP) scenarios and environmental protection (EP) scenarios contribute to mitigating eutrophication, the EI values are 38.2 and 38.1, respectively. The results provide a potential mechanistic explanation that river eutrophication is a consequence of unreasonable landscape pattern evolution. Guiding the landscape patterns evolution based on critical driver factors from a planning perspective is conducive to mitigating river water quality degradation.

Trophic state and potential productivity assessment for Qaroun Lake using spatial techniques

Qaroun Lake is one of the most important Egyptian lakes which, recently, have been exposed to severe degradation in water quality and fish productivity. In this manuscript, Carlson’s trophic state index (CTSI) was used to evaluate the trophic state, while the trophometric index (TMI) was used to assess the potential productivity of Qaroun Lake. The present study is one of the initial attempts to investigate these indices in Qaroun Lake. To achieve this work, an integrated multidisciplinary approach was adopted integrating field investigation, geographic information system, and data analysis. CTSI combines three variables of water quality: chlorophyll-a (CHL-a), total phosphorus (TP), and transparency measured by Secchi disk depth (SDD). The result of overall CTSI showed the hypereutrophic state is represented by 62% and eutrophic state is represented by 38% of the total lake’s area. Moreover, the calculated TMI indicated the average potential productivity value (PP) is 619 t. It can be concluded that the hypereutrophic is the dominant state in Qaroun Lake. The present study recommends the application of TMI model to evaluate and monitor the changes in Qaroun Lake’s potential productivity in response to the changing environmental conditions and other biological pressures (e.g., Isopoda paraside).

ENVIRONMENTAL POLLUTION: IMPACT ON SHIPS AND INFRASTRUCTURE ON KARACHI HARBOR

Karachi harbor has an immense operational infrastructure of Pakistan National Shipping Corporation (PNSC), Pakistan Navy (PN), and Pakistan Maritime Security Agency (PMSA). It is significant for the readiness of PN and PMSA for peace and wartime operations. Although the Government of Pakistan has declared Karachi Port Complex a National Vulnerable Area, Karachi’s coast receives massive pollutants from various land and sea sources. The primary sources include liquid discharge from industry and solid effluents of the municipality. The non-availability of disposal facilities and the absence of effluent treatment plants add to the misery. Toxic liquids and solid pollutants remain in the harbor for extended intervals. This pollution threatens the marine environment and ocean life and degrades water quality. These pollutants also affect the life of assets and infrastructures, including incoming and parked ships, which deteriorate fast. This paper includes the sources of pollution and the current state of Karachi harbor. Also, possible outcomes of the growing pollution fall into the domain of this study.

Exploring the acid neutralizing effect in rainwater collected at a tropical urban area: Central Valley, Costa Rica

We report on the chemical and the carbon isotopic composition of dissolved inorganic carbon (DIC) of rainwater collected between May and October 2020 in the Central Valley, Costa Rica. Precipitation samples were collected daily (N = 55) and analyzed for major ions, DIC, and δ13CDIC. Significant correlation (p < 0.05) between main acidic (SO42− and NO3−) and major alkaline (Ca2+ and NH4+) species confirmed a very effective acid neutralization effect in rainwater (average pH: 5.90 ± 0.74). Significant temporal variations (p < 0.05) of δ13CDIC indicated the contribution of carbonate salts in rainwater from May to October but also CO2 dissolution at the beginning of the wet season (May), probably due to increased CO2 emissions from soil degassing. Temporal changes of Ca2+ neutralization factors followed the observed changes in δ13CDIC, which confirmed the high buffer capacity of precipitation in our study. HYSPLIT analysis also revealed long-range contributions of pedogenetic carbonates (e.g., Saharan dust) responsible for the acid neutralization capacity of rainwater (e.g., from July to September). Principal component analysis showed that four main factors explain 65% of the variance are: i) acid neutralization processes (Ca2+ neutralization factor), ii) marine salts (Cl−, Na+), iii) fossil fuels (SO42−, NO3−), and iv) agriculture/fertilizers (NO3−, NH4+, K+). Our study demonstrated that a combined approach of chemical, isotope, and statistical analysis techniques can help unravel the mechanism of acid neutralization of rainwater in tropical urban areas. This information has strong implications for future studies related with the impact of acid deposition on ecosystem functioning, water quality, and infrastructure degradation.

Agricultural land management alters the biogeochemical cycling capacity of aquatic and sediment environments

Nutrient loading from agricultural landscapes continues to pose a threat to downstream aquatic systems, contributing to degraded water quality and eutrophication. Nutrient loading to adjacent aquatic environments is influenced by the type of applied fertilizer (chemical and manure), field management, and seasonal weather patterns. The risk these nutrients pose to downstream systems may be mitigated by the capacity of the microbial community in receiving water catchments to process those nutrients. This study evaluated the interactive effects of agricultural practices and seasonal weather patterns on nutrient cycling communities in catchment ponds within a long-term Agriculture and Agri-Food Canada research trial, located in the Lake Erie watershed in Ontario, Canada. Microbial nitrogen (N) and P (phosphorus)-cycling functions in water and sediment environments, receiving direct tile drainage and surface runoff flow, were quantified with respect to nutrient loads from liquid cow manure, solid cow manure, inorganic phosphorus, and a control fertilizer treatment, over a full year. High bacterial nitrification potential in the water column coincided with nitrogen loading, which was driven by manure/fertilizer application, tillage practices, and precipitation. The highest overall phosphorus concentrations occurred in the liquid cow manure treatment, but the availability of phosphorus in all treatments was strongly associated with microbial phosphorus mobilization capacity in both aquatic and sediment environments. Seasonality also influenced the aquatic environment, where N and P- cycling potential significantly increased during the winter months. Microbial functional potential in the water column was strongly influenced by the external environment, including season and precipitation, while the functional potential in the sediment was more resistant to environmental fluctuations, and was primarily influenced by long-term management fertilizer/manure practices. Overall, this study provides evidence that agricultural management alters the capacity of the microbial communities in adjacent aquatic environments to process nutrients.

Tracing surface water pollution in China’s supply chain

Decades of economic growth in China were enabled by rapid industrialization with insufficient water quality controls. Previous studies have traced water pollution discharges or grey water footprint using the multi-regional input–output (MRIO) model. However, there is a research gap in understanding the relation between surface water pollutant concentrations and final consumption of local and external basins. Here, we present the first national analysis to map surface water quality degradation in watersheds embedded in China’s supply chains. To do this, we developed a basin-specific relationship between surface water pollution concentration and discharge, and combined it with the MRIO model to trace the water pollution of different basins through the trade of products and services. We find that ∼50% chemical oxygen demand (COD) and ∼46% ammonium nitrogen (NH4+-N) discharges from production processes can be traced to consumer demands beyond the basin where the pollution was initially released. 0.3–2.2 mg/L COD and 0.03–0.31 mg/L NH4+-N water quality degradation (the range indicates pollution concentration in different basins) can be attributed to final consumption of commodities from other basins in China. International consumers contributed to increased degradation of water quality (0.43 mg/L COD in Huai River Basin and 0.07 mg/L NH4+-N in Hai River Basin). High pollution concentrations were often concentrated in dry North China, because water scarce basins in this region are more susceptible to human pollution loadings. Basins outsourcing water pollution were mainly developed economies that outsourced production and subsequent water quality impairments to other basins. This study highlights the interactions between water quality and supply chains.

Impacts of dyke systems on the distribution of benthic invertebrate communities and physicochemical characteristics of surface water in An Giang, Vietnam.

The dyke system plays a vital role in cultivating rice intensively in the Vietnamese Mekong Delta, which protects rice paddy fields from annual floods. This study aimed to examine whether the full-dyke system (FD, which restricts water exchange for a long time) can cause degradation of surface water quality and reduction in benthic invertebrate biodiversity. The surface water quality and benthic invertebrate community were compared between the FD and semi-dyke systems (SD, which permits water exchange during flooding season) using a large number of samples collected seasonally in 2019. The results showed that the surface water quality within the FD system had significantly higher concentrations of TSS, COD, BOD5, N-NO3-, N-TKN, P-PO43-, and TP than compared to the SD system (p < 0.05), indicating greater pollution levels. The benthic invertebrate community was less diverse in the FD system than in the SD system. Only 17 species (belonging to 4 families) were detected in the FD system, and 30 species (belonging to 5 families) were detected in the SD system. The benthic invertebrate community structure changes and biodiversity loss were associated with degraded water quality. The P-PO43- and TP parameters were negatively correlated with the number of species, density, and biomass in the FD system and with the Shannon-Wiener (H') index in the SD system. In conclusion, the FD system has been degrading water quality and causing biodiversity loss.

Lake and Stream Buffer Zone Widths' Effects on Nutrient Export to Lake Rawapening, Central Java, Indonesia: A Simple Simulation Study

Lake ecosystems in Indonesia face serious environmental problems. One of those problems is eutrophication caused by excessive plant nutrients, particularly nitrogen (N) and phosphorus (P). Water quality degradation and biodiversity loss are the effects of eutrophication. The government of Indonesia (GoI) has issued a regulation on determining lake and stream buffer zones, but it has not been fully implemented in the field. Additionally, the data related to the effects of each buffer zone width is not available. This study aims to begin to fill this gap. It simulates the effect of lake and stream buffer zone widths on nutrient export to Rawapening Lake. The Nutrient Retention sub-model, which is part of InVEST (Integrated Valuation of Environmental Services and Tradeoffs) software, has been used for this research to analyse information from several data sources, including a Digital Elevation Model (DEM) and measurements of soil depth, annual rainfall, land cover/use, watershed/sub-watershed boundaries, and biophysical conditions. Several studies of eutrophication in Rawapening Lake have measured the magnitude of eutrophication but have not discussed the effects of buffer zone widths. Therefore, this study accommodates the updated data on how much effect of buffer zone widths on the reduction of nutrient export. Five scenarios of buffer zone width are considered: 30 m., 90 m., and 150 m, where the lake buffer zone widths and the stream buffer zone width are 30 m. The results indicated that the maximum nutrient export reduction of lake buffer zones was only 2.63% (for N) and 3.56% (for P). On the other hand, the 30 m stream buffer zone width reduced the nutrient export to Rawapening Lake by up to 43.05% for N and by 44.90% for P. A 30 m combined lake and stream buffer zone width slightly increases the nutrient export reduction effectiveness, i.e., 0.41% and 0.56% for N and P, respectively.

Erosion and Sediment Transport Modeling: A Systematic Review

Soil erosion and sediment transport have significant consequences, including decreased agricultural production, water quality degradation, and modification to stream channels. Understanding these processes and their interactions with contributing factors is crucial for assessing the environmental impacts of erosion. The primary objective of this review is to identify a suitable soil erosion and sediment transport model for catchment-scale application. The study considers various model selection processes, including model capability and the spatial and temporal domains for assessing spatiotemporal distributions. The review acknowledges the limitations, uncertainties, and unrealistic assumptions associated with soil erosion and sediment transport models. Models are usually developed with a particular objective, which demands an assessment of capabilities, spatial, and temporal applicability, and catchment-scale applicability. Distributed models are often preferred for catchment-scale applications, as they can adequately account for spatial variations in erosion potential and sediment yield, aiding in the evaluation of erosion-contributing elements and planning erosion control measures. Based on the findings of this study, the authors encourage utilizing models (such as Soil and Water Assessment Tool (SWAT) or Automated Geospatial Watershed Assessment Tool (AGWA)) that can forecast net erosion as a function of sediment output for catchment erosion and sediment yield modeling. This review helps researchers and practitioners involved in erosion and sediment modeling by guiding the selection of an appropriate model type based on specific modeling purposes and basin scale. By choosing appropriate models, the accuracy and effectiveness of sediment yield estimation and erosion control measures can be improved.

Impact of lockdowns and possible quantification of pollution sources on the water quality of the Yamuna River

ABSTRACT The COVID-19 lockdown halted industrial and transportation networks, resulting in a change in the level of pollution. In this study, the analysis of pre- and post-lockdown water quality of the Yamuna River is done, and primary causes are identified, by considering five in situ parameters and four Landsat-8-derived parameters. During the 2020 lockdown, pollution-indicating in situ parameters decreased, with chemical oxygen demand decreasing the most, possibly due to reduced industrial impact. All satellite-derived indices improved during lockdown and post-lockdown periods of 2020. Even in segments with uniform flow, floating algal index and normalized difference vegetation index exhibited lower levels. In contrast, the examination of the 2021 lockdown revealed no noteworthy insights. Mapping the observations with the drainage network and location of common effluent treatment plants revealed that industrial effluents were the dominant cause of water quality fluctuations. This demonstrates the impact of industrial effluents on the degrading water quality of Yamuna.