Surface Water Quality Research Articles

Hormesis, the Individual and Combined Phytotoxicity of the Components of Glyphosate-Based Formulations on Algal Growth and Photosynthetic Activity.

The occurrence of the market-leading glyphosate active ingredient in surface waters is a globally observed phenomenon. Although co-formulants in pesticide formulations were considered inactive components from the aspects of the required main biological effect of the pesticide, several studies have proven the high individual toxicity of formulating agents, as well as the enhanced combined toxicity of the active ingredients and other components. Since the majority of active ingredients are present in the form of chemical mixtures in our environment, the possible combined toxicity between active ingredients and co-formulants is particularly important. To assess the individual and combined phytotoxicity of the components, glyphosate was tested in the form of pure active ingredient (glyphosate isopropylammonium salt) and herbicide formulations (Roundup Classic and Medallon Premium) formulated with a mixture of polyethoxylated tallow amines (POEA) or alkyl polyglucosides (APG), respectively. The order of acute toxicity was as follows for Roundup Classic: glyphosate < herbicide formulation < POEA. However, the following order was demonstrated for Medallon Premium: herbicide formulation < glyphosate < APG. Increased photosynthetic activity was detected after the exposure to the formulation (1.5-5.8 mg glyphosate/L and 0.5-2.2 mg POEA/L) and its components individually (glyphosate: 13-27.2 mg/L, POEA: 0.6-4.8 mg/L), which indicates hormetic effects. However, decreased photosynthetic activity was detected at higher concentrations of POEA (19.2 mg/L) and Roundup Classic (11.6-50.6 mg glyphosate/L). Differences were demonstrated in the sensitivity of the selected algae species and, in addition to the individual and combined toxicity of the components presented in the glyphosate-based herbicides. Both of the observed inhibitory and stimulating effects can adversely affect the aquatic ecosystems and water quality of surface waters.

Pemanfaatan Magnetic Biochar dari Cangkang Sawit Sebagai Adsorben untuk Menyisihkan COD, Total Suspended Solid, Minyak dan Lemak dalam Air Buangan Domestik

Greywater is wastewater from domestic activities sourced from kitchens, bathrooms, and laundry water. Greywater discharged directly into the environment can cause a decrease in surface water quality due to its high organic content, nutrients, pathogenic bacteria, and detergents and surfactants. One method that can be used to remove organic and nutrient content is adsorption. The success of the adsorption process is determined by several factors, such as adsorbent type, dosage, contact time, and others. One adsorbent that has attracted the attention of many researchers in recent years is magnetic biochar. This study aims to remove chemical oxygen demand (COD), total suspended solids (TSS), oil, and grease from greywater with a magnetic biochar adsorbent made from palm shells. The study was conducted by varying the dose of 1.2–8.55 g/l and the contact time of 30–150 minutes. The results showed that increasing the dose and contact time can increase the removal efficiency of COD, TSS, oil, and grease. The best results were obtained at a dose of 8.55 g/l and a contact time of 150 minutes. The removal of COD, TSS, oil, and grease was 87.91%, 88.46%, and 99.96%, respectively.

Spatiotemporal comprehensive evaluation of water quality based on enhanced variable fuzzy set theory: A case study of a landfill in karst area

Water quality assessment is a crucial step in water resource management and pollution prevention, and is essential for achieving sustainable development. Current methods for evaluating water quality often fall short of meeting the needs of water resource management due to the lacks of accuracy and applicability. In this paper, an enhanced water quality evaluation system was established by Principal Component Analysis / Factor Analysis (PCA/FA), Analytic Hierarchy Process / Entropy Weight Method / Game Theory (AHP/EWM/GT) and Variable Fuzzy Set Theory (VFST). The accuracy of this method was verified by evaluating the water quality of a landfill in a karst area and comparing with the conventional evaluation models. The results indicated that the highest influence on groundwater quality in the study area came from human factor, dissolved solid factor, biological factor, and nutritional factor. The quality of surface water and groundwater in the study area was primarily Grade Ⅱ, accounting for 62.5% and 75%, respectively. The predominant groundwater type was HCO3-Ca·Mg, which was strongly affected by karstification. The NH3-N and TP in the surface water had the highest variability, and the variation coefficients of K+, Na+, Ca2+, Cl−, NH3-N, NO3−, TDS, and TH in the groundwater were greater than 1. The surface water quality gradually improved between 2018 and 2019. Overall, the groundwater quality in the southern and central regions was inferior to that in the northern and surrounding areas. There could be a hydraulic link between the surface water and landfill in the research location, while karstification and leachate primarily impacted the groundwater. The water quality evaluation method established in this study can make a significant contribution to water resource management, which has important practical significance for environmental protection and indirect social value to the public.

Аналіз стану умов відтворення аборигенних іхтіопопуляцій Стир-Горинського гідроекологічного коридору на території Західного Полісся України

Purpose. To investigate the state of reproduction conditions, current and in dynamics since 1922, for native ichthyopopulations (NI) of the Styr-Horyn Hydroecological Corridor (HEC) on the territory of the Western Polissiya of Ukraine. Methodology. The Styr-Horyn HEC was studied according to the following parameters: hydrological regime and duration of water stay on the floodplain; state of the basin surface; speed of channel flow; amount of water exchange; quality of aquatic environment; natural-temporal changes of the channel, floodplains, tributary network; number of ecotones; qualitative and quantitative characteristics of fish juveniles. The hydrological regime was studied using the analysis of runoff hydrographs located in the Volyn, Rivne, and Zhytomyr regions starting from 1922. To assess water quality, KND No. 211.1.4.010-94, “Methodology of ecological assessment of surface water quality by relevant categories”, SOU – 05.01.37-385: 2006, was used. Ichthyological studies were carried out in the field and laboratory according to standard methods with the use of identification keys primarily using the data of test catches and the classification of V. G. Nikolskyi. Statistical and mathematical analysis was performed using the Delfi programming language, relevant computer programs (Mathcad, Excel, Xara) and formulas, including authors’ ones. Findings. An analysis of the Styr-Horyn HEC was carried out on the basis of restorative ichthyoecology using the basin principle and riskology approaches. The hydroecological and ichthyoecological factors affecting the reproduction of NI were studied. The natural fish reproduction localities (NFRL) in this region have been identified. Originality. For the first time, a comprehensive analysis of the state of the reproduction conditions of the Styr-Horyn HEC on the territory of the Western Polissiya of Ukraine was carried out starting from 1922. In addition, a prognostic assessment of the NFRL of this HEC on the territory of Ukraine has been provided. Practical value. The conducted studies are already successfully used in the work of higher educational institutions of Ukraine in the field of training “Aquatic bioresources and aquaculture”.In addition, they are used by fish protection authorities in several regions of Ukraine, in particular for certification of wintering grounds. In the future, their implementation is planned at the level of the national environmental protection policy and in the preparation of regulatory documents regarding the determination of the damage caused and the extent of the damage. Keywords: Pripyat River, Horyn River, Styr River, hydroecology, ichthyoecology, Western Polissiya, hydroecological corridor, natural fish reproduction localities, spawning grounds, wintering grounds, fish migrations, native ichthyofauna.

Assessment of Surface Water Quality Using Entropy-WQI, Fuzzy-TOPSIS Analysis, Irrigation Indices and Spatial Interpolation Approaches in Mahanadi River Basin, Odisha, India

The current study is aimed at the assessment of surface water quality in the Mahanadi River, Odisha and its suitability for agricultural and consumption purposes, utilizing various indices of water quality such as Entropy Water Quality Index, Osmotic Pressure, Potential Salinity, Residual Sodium Carbonate, Sodium Adsorption Ratio and Kelly Index. Multi-criteria decision-making (MCDM) mechanisms namely, fuzzy-TOPSIS modeling and GIS tools were used; additionally, the suitability of river water for industrial uses was evaluated using indices such as Ryznar Stability Index and Puckorius scaling index. From 2019 to 2023, samples from 19 sampling stations were collected and 21 physical and chemical parameters were evaluated and compared with the normative recommendations advised by WHO. The dispersion of surface water quality on land use changes was discovered using GIS approaches. Additionally, using ArcGIS software, the spatial variability of hydrological processes was determined using the IDW interpolation approach. The pH levels of certain sampling points were slightly above the acceptable limit. Tests revealed that the Total coliform (TC) and turbidity levels in the water samples exceeded critical limits, particularly in areas of the urban river basin that were irrigated with wastewater. The calculated values of EWQI lie between 14.6 and 1066. Entropy WQI values designated 2 locations (ST-8, 19) out of 19 sampling locations as poor category and another one testing point (ST-9) as extremely poor category. The study found that 84.21% of the water samples were of excellent quality for drinking, while 15.78% of locations had poor or extremely poor water quality. However, some indices were favorable for the usage of the water for irrigation purposes. Magnesium hazard (MH) readings at two sampling sites were above 50%, indicating that they were inappropriate for irrigation. USSL (United States Salinity Laboratory) diagrams categorized the water samples as C1-S1 (low salinity and low sodium) for almost 18 sites and C4-S3 (very high salinity and high sodium) for only ONE sample, respectively, suggesting river water’s irrigation suitability. Further, Piper diagrams revealed that most investigated waters were Ca2+-Mg2+-Cl- water type. In a later stage, from Gibb’s diagram, it was found that most samples fall under the rock-water dominance. Based on the above and all other investigation results, it was concluded that water is suitable for irrigation and drinking purposes in all sites, except for three locations. The reason may be due to long-term use of wastewater, anthropogenic activities, over-extraction of surface water and changes in land use patterns. To sum up, it is advantageous to combine physicochemical properties, EWQI, fuzzy-TOPSIS, and GIS tools to evaluate surface water suitability for consumption and agriculture and their regulating variables. The strategy utilized in this work will aid the water management authorities in ensuring the supply of safe water for stakeholders.

Monitoring the Industrial waste polluted stream - Integrated analytics and machine learning for water quality index assessment

The Water Quality Index (WQI) is a primary metric used to evaluate and categorize surface water quality which plays a crucial role in the management of fresh water resources. Machine Learning (ML) modeling offers potential insights into water quality index prediction. This study employed advanced ML models to get potential insights into the prediction of water quality index for the Aik-Stream, an industrially polluted natural water resource in Pakistan with 19 input water quality variables aligning them with surrounding land use and anthropogenic activities. Six machine learning algorithms, i.e. Adaptive Boosting (AdaBoost), K-Nearest Neighbors (K-NN), Gradient Boosting (GB), Random Forests (RF), Support Vector Regression (SVR), and Bayesian Regression (BR) were employed as benchmark models to predict the Water Quality Index (WQI) values of the polluted stream to achieve our objectives. For model calibration, 80% of the dataset was reserved for training, while 20% was set aside for testing. In our comparative analyses of predictive models for water quality index, the Gradient Boost (GB) model stood out the fittest for its precision, utilizing a combination of just seven parameters (chemical oxygen demand, total organic carbon, oil & grease, Ammonia- nitrogen, arsenic, nickel and zinc), surpassing other models by achieving better results in both training (R2 = 0.88, RMSE = 7.24) and testing (R2 = 0.85, RMSE = 8.67). Analyzing feature importance showed that all the selected variables, except for NO3 N, TDS and temperature had an impact on the accuracy of the models predictions. It is concluded that the application of machine learning to assess water quality in polluted environments enhances accuracy and facilitates real-time tracking, enabling proactive risk mitigations.

Evaluating Relationship between Surface Water Quality and Zooplankton Diversity in Coastal Areas of Tien Giang Province, Vietnam

The zooplankton diversity is the most important ecological parameter for water quality assessment, as these small creatures are sensitive to any changes in water quality, hence the objective of this study as to evaluate the relationship between surface water quality and zooplankton diversity in the coastal areas of Tien Giang province, Vietnam using appropriate standard methods. The results showed that the coastal water quality had high concentrations of suspended solids, ammonium and coliforms. A total of 71 zooplankton species with a total density ranging from 3,219,383 to 24,993,634 individuals/m3 were identified. Among the zooplankton species, Copepoda nauplius appeared at all monitoring stations, predominating with a density ranging from 740,800 to 7,555,250 individuals/m3. The values of the Shannon-Wiener diversity index (H') ranged from 1.54 to 2.37, reflecting the coastal water quality in the study area from polluted to mildly polluted. The coastal water variables of pH, salinity, DO, NH4+-N and coliform were closely correlated with the density of zooplankton species. The relationship between surface water quality and zooplankton diversity could be a basis for selecting biological indicators to monitor coastal water quality.

Piped-slow-release calcium nitrate dosing: A new approach to in-situ sediment odor control in rural areas

Calcium nitrate addition is economically viable and highly efficient for the in-situ treatment of contaminated sediment and enhancement of surface water quality, particularly in rural areas. However, conventional nitrate addition technologies have disadvantages such as excessive nitrate release, sharp ammonium increase, and weakened sulfide oxidation efficiency owing to rapid nitrate injection into the sediment. To resolve these defects, we propose a piped-slow-release (PSR) calcium nitrate dosing method and investigate its treatment efficiency and underlying mechanisms. The results illustrated that PSR dosing had a longer half-life (t1/2 = 5.08 days) and a lower maximum apparent nitrate escape rate of 1.28 % than conventional nitrate injection and other dosing methods. In addition, the PSR managed the inorganic nitrogen release into the overlying water, and after the treatment, the nitrate, ammonium, and nitrite concentrations of 0 mg/L, 8.60 mg/L, and 0 mg/L on day 28 were close to those of the control group (0 mg/L, 8.76 mg/L, and 0 mg/L, respectively). Moreover, the PSR method maintained a moderate nitrate concentration of approximately 3000 mg/L in sediment interstitial water by its controlled-release design, thus greatly enhancing the sulfide oxidation efficiency by relieving the inhibitory effects of high nitrate concentrations, with 83.0 % sulfide being eradicated within 5 days. Sulfide-ferrous nitrate reduction (denitrification and dissimilatory nitrate reduction to ammonium) genera (e.g., Sulfurimonas, Thiobacillus, and Thioalkalispira) were successively enhanced and dominated the microbial community, and the related functional genes displayed high relative abundances. These results imply that the PSR dosing method for calcium nitrate, characterized by flexible operation, high efficiency, low cost, and controllable processes, is appropriate for remediating black-odorous sediment in rural areas.

Solute fluxes in headwater catchments with contrasting anthropogenic impact

Understanding the response of headwater catchments to increasing anthropogenic influences is one of the key issues in hydrological and geomorphological research. Two headwater catchments with contrasting human impacts on the environment were chosen to determine changes in surface water chemistry and solute fluxes. In one catchment, 22 % of the forest area was cleared in 2013 and in the other, 75 % of the arable lands was converted to grassland and forest in the last 25 years. Atmospheric input and solute mass balance were analysed using homogeneity Pettitt test. It seems that in both areas, a very important factor affecting solute fluxes was most likely changes, or lack thereof, in soil erosion. In the partially clear-cut catchment, a small clear-cut area and adequate protection of the soil cover had little effect on the stream water chemistry, and the total solute mass balance remained unchanged during the study period. In this catchment, the more pronounced effect on solute fluxes was using de-icing salts in winter, which contributed to a 62 % increase in total solute flux (mainly by supplying Na+ and Cl−, but also Ca2+, Mg2+ and K+). In a catchment with a decrease in arable lands, there was a 55 % decrease in total solute mass balance (including mass balance of Ca2+, Mg2+, Na+, K+, NH4+, SO4−, NO3−, Cl−) in the stream likely associated with a decrease in soil erosion and fertilization. In both catchments there was a decrease in total monthly atmospheric input (especially in input of NH4+, SO4− and NO3−) of 53 % and 21 %, respectively, over the study period. To summarize, the road salting has increased the amount of transported solutes in the stream and deteriorated surface water chemistry, while the reduction of arable land area has reduced the amount of transported solutes in the stream and improved surface water quality.

The longevity evaluation of multi-metal stabilization by MgO in Pb/Zn smelter-contaminated soils.

The re-mobilization risks of potentially toxic elements (PTEs) during stabilization deserve to be considered. In this study, artificial simulation evaluation methods based on the environmental stress of freeze-thaw (F-T), acidification and variable pH were conducted to assess the long-term effectiveness of PTEs stabilizedby MgO in Pb/Zn smelter contaminated soils. Among common stabilizingmaterials, MgO was considered asthe best remediation material, since PTEs bioavailability reduced by 55.48% for As, 19.58% for Cd, 10.57% for Cu, and 26.33% for Mn, respectively. The stabilization effects of PTEs by MgO were best at the dosage of 5 wt%, but these studied PTEswould re-mobilize after 30 timesF-T cycles. Acid and base buffering capacity results indicated that the basicity of contaminated soils with MgO treatment reduced under F-T action, and the leachedPTEs concentrations would exceed the safety limits of surface water quality standard in China (GB3838-2002) after acidification of2325 years. No significant changes were foundin thepH-dependent patterns of PTEs before and after F-Tcycles. However, after F-Tcycles, the leaching concentrations of PTEs increased due to the destruction of soil microstructure and the functionality of hydration products formed by MgO, as indicated by scanning electron microscopy (SEM)coupled withenergydispersive Xray spectroscopy (EDS) results. Hence, these findings would provide beneficial references for soil remediation assessments ofcontaminated soils under multi-environmental stress.

Domestic Solid Waste Management in Tho Nghiep Commune, Xuan Truong District, Nam Dinh Province: Current Status and Solutions

This article presents research results on the current status and proposes solutions to improve the efficiency of domestic solid waste (DSW) management in Tho Nghiep commune, Xuan Truong district, Nam Dinh province. The survey was conducted for 170 households and the results show that 40.59% of households process a part of DSW by themselves (=equivalently 10.8% of total DSW) while the rest is transferred to the commune's garbage collection team. The other 59.41% of the households transfer all the solid waste to the commune's waste collection team for treatment at the centralized area. The average volume of DSW released in the whole commune is about 5.5 tons/day, collected with a frequency of three days/week. The collected solid waste is further classified and treated at the commune's incinerator treatment zone by Truong Phat Agricultural Service and Green Environment Cooperative. The environmental assessment of Tho Nghiep DSW treatment area was conducted in November 2022. The results from the incinerator exhaust gas samples showed that four out of five parameters (including SO2, CO, NOx, HCl) are below the allowable standards, only one out of five parameters (Total dust) are higher than the allowable standard of QCVN 61-MT:2016/BTNMT on DSW incinerators. For the surface water samples taken at the southern infield ditch of the incinerator, all eight parameters (pH, BOD5 (at 20oC), COD, TSS, NH4+, NO3-, PO43-, Coliforms) were below permissible standard of QCVN 08-MT:2015/BTNMT on surface water quality. Based on these results, a few proposed solutions have been identified to improve the effectiveness of DSW management in the study area.&#x0D;

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

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

Impacts of land use changes on discharge and water quality in rivers and streams: Case study of the continental United States

AbstractWater quality trends in streams and rivers are impacted by several factors including land use of the watershed; however, it is unclear what influence changes in the land use of a watershed subsequently have on changes in discharge and water quality in streams and rivers. This study seeks to fill this gap by evaluating the relationship between changes in land use and changes in discharge and water quality at United States Geological Survey (USGS) stream gages over the period of 2008–2016. Using land cover data and discharge and water quality data from 60 USGS gages, regression methods were applied to determine the strength of relationship between land use changes and changes in water quality and quantity. Trends in discharge and water quality were mixed, with a majority of watersheds demonstrating a decrease in dissolved oxygen and turbidity, no overall trend for discharge, and increases in specific conductance. A regression analysis revealed that discharge, turbidity, and specific conductance were correlated with changes in individual land use types with an R2 between 0.12 and 0.25. Combining the influences of multiple land uses in multivariate regression improved the predictions for discharge (R2 0.58) and specific conductance (R2 0.47), highlighting the magnitude for which land cover changes influence trends in water quality. Overall, this study demonstrates the impact that large‐scale land use changes have on surface water quality.

Physicochemical Analysis of Surface Water in Rohri Canal from Sukkur Barrage to Mehrabpur

The purpose of this study was to assess the effect of domestic and industrial waste discharge on the surface water quality of Rohri Canal in the stretch of the canal from Sukkur Barrage to Mehrabpur town. Eight sampling points were selected along the canal focusing on canal locations near major settlements. The parameters studied were temperature, pH, turbidity, hardness, alkalinity, total dissolved solids and suspended solids, chlorides, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and E-coli. The average value of BOD and COD at the sampling stations were recorded as 212 mg/L and 423 mg/L respectively, which exceed the permissible surface water limits for drinking and irrigation purposes. The results indicate significantly higher value of BOD in sampling locations where there are major settlements and there is a continuous inflow of untreated sewage into the canal. The pH values at all the sampling sites were found within the drinking and irrigation water quality standards whereas the TDS values at only sampling stations (3 and 4) exceeded these limits. The turbidity values of the samples ranged from 237 to 821 NTU, exceeding the WHO drinking water quality standards for this parameter. The values of the water quality parameters including hardness (range 146 to 300 mg/L), chlorides (range 36 to 103 mg/L) and alkalinity (range 120 to 230 mg/L) were found well below the limits of WHO drinking water quality standards. The turbidity values of the samples ranged from 237 to 821 NTU and exceeded the WHO drinking water quality standards for this parameter. At all the sampling sites located near major settlements low levels of dissolved oxygen and the presence of E.coli were recorded. The results revealed that the continuous inflowing of untreated or un-treated sewage and industrial effluents into the canal has changed its physicochemical and biological characteristics, which make it unfit for human consumption and can have long-term irrevocable ecological threats if left unmanaged

Deep optimization of water quality index and positive matrix factorization models for water quality evaluation and pollution source apportionment using a random forest model

Effective evaluation of water quality and accurate quantification of pollution sources are essential for the sustainable use of water resources. Although water quality index (WQI) and positive matrix factorization (PMF) models have been proven to be applicable for surface water quality assessments and pollution source apportionments, these models still have potential for further development in today's data-driven, rapidly evolving technological era. This study coupled a machine learning technique, the random forest model, with WQI and PMF models to enhance their ability to analyze water pollution issues. Monitoring data of 12 water quality indicators from six sites along the Minjiang River from 2015 to 2020 were used to build a WQI model for determining the spatiotemporal water quality characteristics. Then, coupled with the random forest model, the importance of 12 indicators relative to the WQI was assessed. The total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (CODCr), dissolved oxygen (DO), and five-day biochemical oxygen demand (BOD5) were identified as the top five significant parameters influencing water quality in the region. The improved WQI model constructed based on key parameters enabled high-precision (R2 = 0.9696) water quality prediction. Furthermore, the feature importance of the indicators was used as weights to adjust the results of the PMF model, allowing for a more reasonable pollutant source apportionment and revealing potential driving factors of variations in water quality. The final contributions of pollution sources in descending order were agricultural activities (30.26%), domestic sewage (29.07%), industrial wastewater (26.25%), seasonal factors (6.45%), soil erosion (6.19%), and unidentified sources (1.78%). This study provides a new perspective for a comprehensive understanding of the water pollution characteristics of rivers, and offers valuable references for the development of targeted strategies for water quality improvement.

Comparative study of chemical speciation and leaching feature of typical heavy metals in coarse and fine slags from the entrained-flow coal gasification

ABSTRACT The dissimilarity in chemical speciation and release properties of heavy metals will result in varying levels of environmental hazards and potential applications of coal gasification coarse and fine slags. The distribution, chemical speciation, leaching features, and potential environmental risks of heavy metals (Cr, Cu, Cd, Zn, Pb, and Mn) in coarse and fine slags from different coal gasification processes were revealed and compared by the sequential chemical extraction method, Horizontal vibration method, and pH-dependent leaching experiments. The results show that Cr (516.78 mg/kg) in coarse slag, Zn (348.50 mg/kg) and Pb (214.78 mg/kg) in fine slag are highly enriched and the content exceeds the screening value, indicating the need for better management during stockpiling and landfilling. The distribution of Cr, Cu, Pb, and Mn in residual state, Zn in Fe-Mn oxide bound state, and Cd in unstable bound state is the highest in both coarse slag and fine slag. The leaching toxicity of heavy metals (HMs) does not exceed the standard, but the leachate is classified as Level V surface water or groundwater quality due to the leaching concentration of Pb exceeding 0.1 mg/L. Furthermore, leaching of Cr, Zn, Cd, and Pb in fine slag is much more dependent on pH compared to coarse slag, and the concentrations of Zn and Pb exceed emission standards at pH < 3.0. The high concentration of heavy metals caught on the surface of fine slag is more harmful to the environment. The properties of HMs in the slags and pH of the application environment must be comprehensively considered before coal gasification slag disposal, especially fine slag.

DNA extraction using FTA Elute cards for detection and enumeration of fecal indicator bacteria in the Chao Phraya River, Thailand

Utilizing molecular methods for monitoring and determining water quality in developing countries can be problematic. Effective extraction and storage of DNA from environmental samples is especially difficult due to lack of access to sufficient laboratory facilities for molecular work. Use of a commercial product for the extraction of DNA, as well as its application in determining the microbial quality of surface waters, was evaluated and compared. Surface water samples collected from the Chao Phraya River in Thailand were processed to enumerate Escherichia coli. Quantification was done through culture methods (Colilert Quanti-tray) and quantitative real-time PCR (SYBR green and Taqman assays). Processing of surface water samples and culture enumeration of E. coli was done in Thailand, while DNA extraction and enumeration using real-time PCR was done in Korea. E. coli MPN counts were mean log 2.89/100ml. Quantitative real-time PCR assays counts ranged from 2.38 to 3.59 mean log CFU/100 ml. Taqman PCR assays had no significant difference in mean log counts compared to conventional culture methods. However mean log counts of SYBR green PCR assays were significantly higher than counts obtained by culture methods and Taqman PCR assays (P&lt;0.05). Results demonstrated FTA Elute cards can be employed for the extraction of microbial DNA from surface waters and have potential use in detection of fecal indicator bacteria from environmental water samples.

Bridging the divide between inland water quantity and quality with satellite remote sensing: An interdisciplinary review

AbstractThe quantity and quality of surface water are inherently connected yet are overwhelmingly studied separately in the field of remote sensing. Remotely observable water quantity (e.g., water extent, water elevation, lake/reservoir volume, and river discharge) and water quality (e.g., color, turbidity, total suspended solids, chlorophyll a, colored dissolved organic matter, and temperature) parameters of inland waterbodies interact through a series of hydrological and biogeochemical processes. In this review, we analyzed trends in remote sensing publications to understand the prevalence of studies on the quantity versus quality of open‐surface inland waterbodies (rivers, streams, lakes, and reservoirs) as well as identified opportunities for integrating both water quality and quantity sensing in future work. Our bibliometric analysis found that despite the increasing number of publications using remote sensing for inland waterbodies, few studies to date have used remote sensing tools or approaches to simultaneously study water quantity and quality. Ultimately, by providing insights into potential integration of the water quality and quantity studies, we aim to identify a pathway to advance the understanding of inland water dynamics and freshwater resources through remote sensing.This article is categorized under: Water and Life &gt; Methods Science of Water &gt; Water Quality Water and Life &gt; Nature of Freshwater Ecosystems Science of Water &gt; Methods

Effects of Land Use Types on Water Quality at Different Buffer Scales: Tianjin Section of the Haihe River Basin as an Example

It is important to explore the relationship between land use types and water quality to improve the surface water environment. Based on monthly water quality monitoring data from 16 nationally controlled surface water quality monitoring stations in Tianjin and land use data in 2021, GIS spatial analysis and mathematical and statistical methods were used to study the influence of land use types on surface water quality in buffer zones at different scales. The results showed that:① the land use types in the study area were mainly construction land, farmland, and water areas, which had significant effects on river water quality. Except for water temperature (WT) and pH, the farmland, construction land, and water areas were negatively correlated with each water quality indicator; forest land and grassland were positively correlated with dissolved oxygen (DO) and total nitrogen (TN) and negatively correlated with other water quality indicators. ② The water quality indicators showed obvious spatial differences in different seasons. The pH, DO and TN concentrations were higher in the dry season, whereas the permanganate index, ammonia nitrogen (NH4+-N), and total phosphorus (TP) concentrations were higher in the rainy season. ③ The results of the RDA analysis showed that the 800 m buffer zone land use had the greatest explanatory power for water quality changes in the dry season (50.4%), whereas the 3 000 m buffer zone land use could explain the water quality changes in the rainy season to the greatest extent (49.6%); from the average explanation rate of the dry and rainy seasons, the 3 000 m buffer zone was the best impact scale (50.0%) on water quality indicators in Tianjin. ④ The partial least squares regression (PLSR) analysis showed that the most important variables affecting surface water quality changes were construction land, farmland, and water areas. The predictive ability of the PLSR model of most water quality indicators was stronger in the dry season than that in the rainy season. In the dry season, all water quality indicators, except WT and pH, were most influenced by farmland. In the rainy season, construction land had the greatest influence on WT and NH4+-N concentrations, and the most important influencing factor for the remaining water quality indicators was still farmland. This study showed that the rational planning of land use types within 3 000 m of rivers or lakes was beneficial to improving the water quality of surface water.

Spatial Correlations between Nitrogen Budgets and Surface Water and Groundwater Quality in Watersheds with Varied Land Covers

Anthropogenic nitrogen (N) inputs can have detrimental environmental effects, necessitating a comprehensive understanding of the nitrogen budget (NB) and its spatial correlation with the water quality. This study, utilizing a 2016 dataset, scrutinized 850 subwatersheds with diverse land covers across the Republic of Korea (ROK). Employing Geographically Weighted Regression (GWR), it examined the spatial correlations between the NBs and the quality of the groundwater and river water at the watershed scale. Robust correlations (R2 = 0.87) were observed between the groundwater quality and NBs, surpassing those of the surface water (R2 = 0.48). Sensitivity analyses highlighted the importance of high-resolution spatial data in capturing nuances within complex land covers. The integration of such data led to increases in the spatial correlations between the groundwater and river water quality of approximately 0.6–0.9 and 0.3–0.5, respectively. Notably, when the agricultural land cover exceeded 10%, significant enhancements in the spatial correlations were observed, emphasizing the pivotal role of agriculture in nutrient and water quality. At a 10% cropland ratio, the spatial correlations between the watershed-scale NBs and river/groundwater quality increased by approximately 76% and 501%, respectively. This study provides novel insights into the spatial relationships among NBs, water quality, and land use, highlighting the significance of high-resolution data and the impact of agricultural practices on watershed management. These findings contribute valuable information for developing strategies to mitigate nitrogen pollution.