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Water, Volume 14, Issue 2 (January-2 2022) – 139 articles

Cover Story (view full-size image): An impact compression test under water-saturated conditions was carried out on an SHPB test system using the half sine wave loading mode, in which the incident stress wavelength was proportional to the length of the rock specimen. The main purpose of these experiments was to explore the difference in mechanical properties between water-saturated granite and air-dried granite as well as the physical mechanism of these phenomena. The dynamic compressive strength of water-saturated granite was found to be higher than that of air-dried granite. The Bernoulli effect of fluid, the adhesion effect of free water, and the Stefan effect of fluid in water-saturated granite were revealed and found to be the essential reasons affecting the dynamic strength of water-saturated granite. View this paper
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11 pages, 938 KiB  
Article
Transcriptome Analysis of the Toxic Effects of Amisulbrom and Isoflucypram on Zebrafish (Danio rerio) Larvae
by Peng Xiao, Wenhua Li, Jinfang Lu and He Zhang
Water 2022, 14(2), 272; https://doi.org/10.3390/w14020272 - 17 Jan 2022
Cited by 2 | Viewed by 2655
Abstract
Fungicides are frequently detected in the water bodies, however, the adverse effects of these fungicides on aquatic lives remain limited. To better understand the adverse effects of amisulbrom (AML) and isoflucypram (ISO) on embryogenesis, zebrafish embryos were exposed to two different fungicides, 0.75 [...] Read more.
Fungicides are frequently detected in the water bodies, however, the adverse effects of these fungicides on aquatic lives remain limited. To better understand the adverse effects of amisulbrom (AML) and isoflucypram (ISO) on embryogenesis, zebrafish embryos were exposed to two different fungicides, 0.75 μM amisulbrom (AML) and 2.5 μM isoflucypram (ISO), for 72 h. Transcriptome sequencing was employed to identify differentially expressed genes (DEGs) after AML and ISO exposure. A total of 571 and 3471 DEGs were detected between the libraries of the two fungicides-treated groups and the control, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that PPAR signaling pathway, phototransduction, ribosome and p53 signaling pathway were significantly enriched in response to both AML and ISO stress. Moreover, a number of DEGs involved in tyrosine metabolism, phagosome pathway, cell cycle pathway, extracellular matrix (ECM) receptor interaction pathway, and arginine and proline metabolism were specially enriched after exposure to AML; a number of DEGs involved in notch signaling pathway, drug metabolism, alanine, aspartate and glutamate metabolism, amino-acyl−tRNA biosynthesis, and protein processing in endoplasmic reticulum were significantly enriched after exposure to ISO. These results provide novel insights into the toxicological mechanisms underlying fish’s responses to fungicides. Full article
(This article belongs to the Special Issue Contaminants and Microbes in Marine, Lake and River Ecosystems under a Climate Change Scenario)
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21 pages, 6300 KiB  
Article
Simulating the Evolution of Da Anglong Glacier, Western Tibetan Plateau over the 21st Century
by Wenqing Zhao, Liyun Zhao, Lide Tian, Michael Wolovick and John C. Moore
Water 2022, 14(2), 271; https://doi.org/10.3390/w14020271 - 17 Jan 2022
Cited by 19 | Viewed by 2256
Abstract
We apply a three-dimensional (3D) full-Stokes model to simulate the evolution of Da Anglong Glacier, a large glacier in the western Tibetan Plateau from the year 2016 to 2098, using projected temperatures and precipitations from the 25-km-resolution RegCM4 nested within three Earth System [...] Read more.
We apply a three-dimensional (3D) full-Stokes model to simulate the evolution of Da Anglong Glacier, a large glacier in the western Tibetan Plateau from the year 2016 to 2098, using projected temperatures and precipitations from the 25-km-resolution RegCM4 nested within three Earth System Models (ESM) simulating the RCP2.6 and RCP8.5 scenarios. The surface mass balance (SMB) is estimated by the degree-day method using a quadratic elevation-dependent precipitation gradient. A geothermal flux of 60 mW m-2 produces a better fit to measured surface velocity than lower heat fluxes and represents a new datum in this region of sparse heat flux observations. The ensemble mean simulated glacier volume loss during 2016–2098 amounts to 38% of the glacier volume in the year 2016 under RCP2.6 and 83% under RCP8.5. Simulation from 2016 to 2098 without ice dynamics leads to an underestimation of ice loss of 22–27% under RCP2.6 and 16–24% under RCP8.5, showing that ice dynamics play an important amplifying factor in ice loss for this glacier, unlike for small Tibetan glaciers where SMB dominates glacier change. Full article
(This article belongs to the Special Issue Energy and Water Cycles in the Third Pole)
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11 pages, 1310 KiB  
Article
Study of the Effect of Leucine on Calcium Carbonate Precipitation in a Circular Economy Perspective
by Giuseppe Mazziotti di Celso, Marina Prisciandaro, Despina Karatza, Dino Musmarra and Amedeo Lancia
Water 2022, 14(2), 270; https://doi.org/10.3390/w14020270 - 17 Jan 2022
Cited by 4 | Viewed by 1964
Abstract
This paper studies the crystallization of calcium carbonate in the presence of leucine—a green additive. The effect of leucine on calcium carbonate precipitation kinetic is particularly interesting since CaCO3 is a valuable product worthy to be recovered from industrial liquid wastes (e.g., [...] Read more.
This paper studies the crystallization of calcium carbonate in the presence of leucine—a green additive. The effect of leucine on calcium carbonate precipitation kinetic is particularly interesting since CaCO3 is a valuable product worthy to be recovered from industrial liquid wastes (e.g., desalination brines) in the circular economy approach. Experiments have been performed in a laboratory scale plant with a supersaturation range which spams from 2 to 120 and two different leucine concentration (0.520 × 10−3 and 1.041 × 10−3 mol/L). Results obtained have been compared with previous published ones, carried out without any additives. From the measurements of induction times for calcium carbonate nucleation, it was established that in solution, the leucine favors the precipitation of calcium carbonate, so it can be considered a promoter in calcium carbonate crystallization and this behavior enhances when raising its concentration in solution. Interfacial tension was determined for both leucine concentration levels, and the values obtained are in the range 51–84 mJ/m2. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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13 pages, 1751 KiB  
Article
Simulation of Denitrification Process of Calcium Nitrate Combined with Low Oxygen Aeration Based on Double Logarithm Mode
by Fan Wang, Fang Yang, Hongjie Gao, Yangwei Bai, Haiqing Liao and Haisheng Li
Water 2022, 14(2), 269; https://doi.org/10.3390/w14020269 - 17 Jan 2022
Cited by 24 | Viewed by 2525
Abstract
In situ remediation of sediment pollution is an important measure for the treatment of urban black-odorous water. In this study, the process of calcium nitrate dosing and low oxygen aeration was used to repair the sediment of black-odorous water body in a glass [...] Read more.
In situ remediation of sediment pollution is an important measure for the treatment of urban black-odorous water. In this study, the process of calcium nitrate dosing and low oxygen aeration was used to repair the sediment of black-odorous water body in a glass container. The variation trend and removal efficiency of ammonia nitrogen and nitrate nitrogen in sediment and overlying water were investigated during the process. By establishing the double logarithm model of calcium nitrate sediment repair process, the change law of ammonia nitrogen and nitrate nitrogen content in sediment under different calcium nitrate dosing conditions was studied, and the denitrification process of different calcium nitrate dosing and low oxygen aeration was simulated. The results showed that by establishing the double logarithm model of calcium nitrate sediment remediation process, when the dosage of calcium nitrate was 6%, the inhibition rate of calcium nitrate on nitrate nitrogen release was the largest. The stable inhibitory concentration of nitrate nitrogen was 11.65 mg/g, and the stable inhibited concentration of ammonia nitrogen was 382.95 mg/kg. The stable inhibitory concentration of nitrate nitrogen and ammonia nitrogen in overlying water was 8.34 mg/L and 16.47 mg/L. Moreover, excessive calcium nitrate (8%) may increase the risk of microbial ecological environment in sediment and weaken the inhibitory effect. The optimum parameters were the calcium nitrate dosage of 6%, the reaction time of 21 days, and the aeration rate of 30 mL/min. Under these conditions, the removal effect of ammonia nitrogen in sediment and overlying water was further improved, and the concentration of nitrate nitrogen was effectively controlled. The stable inhibitory content of nitrate nitrogen in sediment was 5.55 mg/g, and the stable inhibitory content of ammonia nitrogen was 982.79 mg/kg. The stable inhibitory concentration of nitrate nitrogen and ammonia nitrogen in overlying water was 6.55 mg/L and 118.20 mg/L. Based on a simulation, this study provides important technical support for the formulation of a refined endogenous pollution control scheme by controlling the process of calcium nitrate remediation and low oxygen aeration. Full article
(This article belongs to the Special Issue Water and Soil Pollution Restoration)
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2 pages, 160 KiB  
Correction
Correction: Gallagher, J.; Gill, L.W. The Life Cycle Environmental Performance of On-Site or Decentralised Wastewater Treatment Systems for Domestic Homes. Water 2021, 13, 2542
by John Gallagher and Laurence W. Gill
Water 2022, 14(2), 268; https://doi.org/10.3390/w14020268 - 17 Jan 2022
Cited by 1 | Viewed by 1304
Abstract
In the original publication [...] Full article
(This article belongs to the Special Issue On-Site Wastewater Treatment)
4 pages, 208 KiB  
Reply
Reply to AlQasimi, E.; Mahdi, T.-F. Comment on “Aureli et al. Review of Historical Dam-Break Events and Laboratory Tests on Real Topography for the Validation of Numerical Models. Water 2021, 13, 1968”
by Francesca Aureli, Andrea Maranzoni and Gabriella Petaccia
Water 2022, 14(2), 267; https://doi.org/10.3390/w14020267 - 17 Jan 2022
Viewed by 1807
Abstract
This is the reply to the comments by AlQasimi and Mahdi (2022) on the classification attributed to the Lake Ha! Ha! real-field test case by Aureli et al. (2021) in their review of historical dam-break events useful for the validation of dam-break numerical [...] Read more.
This is the reply to the comments by AlQasimi and Mahdi (2022) on the classification attributed to the Lake Ha! Ha! real-field test case by Aureli et al. (2021) in their review of historical dam-break events useful for the validation of dam-break numerical models. While admitting that this test case is affected by the data shortcomings reported by the Discussers, in the authors’ opinion, it should remain included in the group of well-documented test cases due to the large and complete dataset available in digital format. This conclusion is also supported by the fact that the Lake Ha! Ha! case was chosen as a benchmark in the framework of the 2001–2004 IMPACT (Investigation of Extreme Flood Processes and Uncertainty) European project and was then widely used in the literature for the validation of one-dimensional and two-dimensional geomorphic flood models. Full article
(This article belongs to the Special Issue Advances in Dam-Break Modeling for Flood Hazard Mitigation: Theory, Numerical Models, and Applications in Hydraulic Engineering)
19 pages, 5636 KiB  
Article
Optimal Allocation Model for Water Resources Coupled with Ecological Value Factors—A Case Study of Dalian, China
by Jie Zhang, Chong Meng, Shugang Hu and Wei Li
Water 2022, 14(2), 266; https://doi.org/10.3390/w14020266 - 17 Jan 2022
Cited by 5 | Viewed by 2929
Abstract
The surface water ecosystem has important ecological value and plays an important supporting and guarantee role in the sustainable development of human society. In this study, an inexact two-stage stochastic programming (ITSP) model was developed for supporting water resource allocation for the four [...] Read more.
The surface water ecosystem has important ecological value and plays an important supporting and guarantee role in the sustainable development of human society. In this study, an inexact two-stage stochastic programming (ITSP) model was developed for supporting water resource allocation for the four main water sectors (industry, municipal, agriculture, and ecological environment). Several scenarios corresponding to different flow patterns, which reflect different probabilities of water resource availability and environmental carrying capacity, were examined. On the basis of traditional water resource allocation, this model adds consideration of ecological value factors, which is conducive to the synergistic efficiency of socio-economic and ecological water consumption. Results revealed that the water resource carrying capacity, ecological value factors, and water environmental capacity are the main factors affecting the optimal allocation of water resources. Furthermore, the optimal allocation scheme for water resources coupled with ecological value factors were determined to realize the coordinated development of social economic benefits and ecological benefits. The current study findings are of great significance for establishing a rational water resource management system for water resource exploitation and utilization. This model can be used to guide various departments in Dalian to formulate an optimal water resources allocation scheme by considering ecological value factors, and provide a basis for realizing the coordinated development of Dalian’s socio-economic development goals, water resource utilization, and environmental quality improvement. Full article
(This article belongs to the Topic Water Management in the Era of Climatic Change)
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17 pages, 2152 KiB  
Article
Geographical Preference for Installation of Solar Still Water Desalination Technologies in Iran: An Analytical Hierarchy Process (AHP)-Based Answer
by Sina Jafari, Majid Aghel, Ali Sohani and Siamak Hoseinzadeh
Water 2022, 14(2), 265; https://doi.org/10.3390/w14020265 - 17 Jan 2022
Cited by 17 | Viewed by 3171
Abstract
Water shortage is one of the most crucial challenges worldwide, especially in the Middle Eastern countries, with high population and low freshwater resources. Considering this point and the increasing popularity of solar stills desalination systems, as the contribution, this study aims at finding [...] Read more.
Water shortage is one of the most crucial challenges worldwide, especially in the Middle Eastern countries, with high population and low freshwater resources. Considering this point and the increasing popularity of solar stills desalination systems, as the contribution, this study aims at finding the geographical preference for installation of those technologies in Iran, which is one of the biggest and most populated countries in the Middle East. For this purpose, from each climatic zone of Iran, one representative city is chosen, and analytical hierarchy process (AHP), as one of the most powerful tools for systematic decision-making, is applied. Annual fresh water production (AFWP) from the technical aspect, energy payback period (EPBP) from the energy perspective, and investment payback period from the economic point of view are selected as the decision criteria. Obtaining the three indicated indicators is done using artificial neural networks (ANNs) for yield and water temperature in the basin, which are developed by means of the recorded experimental data. The results indicate that hot arid cities with high received solar radiation, or the ones that have a higher water tariff compared to the others, are the preferred places for installation of solar stills. The example of the first category is Ahvaz, while Tehran is representative of the cities from the second category. AHP demonstrates that they are the first and second priorities for solar still installation, with scores of 26.9 and 22.7, respectively. Ahvaz has AWFP, EPBP, and IPP of 2706.5 L, 0.58 years, and 4.01 years; while the corresponding values for Tehran are 2115.3 L, 0.87 years, and 2.86 years. This study belongs to three classifications in the mathematical problems: 1. experimental work (code: 76–05), 2. Neural networks (code: 92B20), 3. and decision problems, (code: 20F10). Full article
(This article belongs to the Special Issue Renewable Energy Systems Flexibility for Water Desalination)
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3 pages, 187 KiB  
Comment
Comment on Aureli et al. Review of Historical Dam-Break Events and Laboratory Tests on Real Topography for the Validation of Numerical Models. Water 2021, 13, 1968
by Eman AlQasimi and Tew-Fik Mahdi
Water 2022, 14(2), 264; https://doi.org/10.3390/w14020264 - 17 Jan 2022
Viewed by 1645
Abstract
This discussion points out that the available data of the Lake Ha! Ha! Dam failure, classified as useful for models’ validation purposes by Aureli et al. (2021), present serious shortcomings that should move the Lake Ha! Ha! Dam from Aureli et al.’s well-documented [...] Read more.
This discussion points out that the available data of the Lake Ha! Ha! Dam failure, classified as useful for models’ validation purposes by Aureli et al. (2021), present serious shortcomings that should move the Lake Ha! Ha! Dam from Aureli et al.’s well-documented test cases to cases with partial or inaccurate datasets. Full article
(This article belongs to the Special Issue Advances in Dam-Break Modeling for Flood Hazard Mitigation: Theory, Numerical Models, and Applications in Hydraulic Engineering)
20 pages, 4546 KiB  
Article
Scaling Up from Leaf to Whole-Plant Level for Water Use Efficiency Estimates Based on Stomatal and Mesophyll Behaviour in Platycladus orientalis
by Yonge Zhang, Bing Liu, Guodong Jia, Xinxiao Yu, Xiaoming Zhang, Xiaolin Yin, Yang Zhao, Zhaoyan Wang, Chen Cheng, Yousheng Wang and Yan Xin
Water 2022, 14(2), 263; https://doi.org/10.3390/w14020263 - 17 Jan 2022
Cited by 2 | Viewed by 2272
Abstract
Prediction of whole-plant short-term water use efficiency (WUEs,P) is essential to indicate plant performance and facilitate comparison across different temporal and spatial scales. In this study, an isotope model was scaled up from the leaf to the whole-plant level, in order [...] Read more.
Prediction of whole-plant short-term water use efficiency (WUEs,P) is essential to indicate plant performance and facilitate comparison across different temporal and spatial scales. In this study, an isotope model was scaled up from the leaf to the whole-plant level, in order to simulate the variation in WUEs,P in response to different CO2 concentrations (Ca; 400, 600, and 800 μmol·mol−1) and soil water content (SWC; 35–100% of field capacity). For WUEs,P modelling, leaf gas exchange information, plant respiration, and “unproductive” water loss were taken into account. Specifically, in shaping the expression of the WUEs,P, we emphasized the role of both stomatal (gsw) and mesophyll conductance (gm). Simulations were compared with the measured results to check the model’s applicability. The verification showed that estimates of gsw from the coupled photosynthesis (Pn,L)-gsw model accounting for the effect of soil water stress slightly outperformed the model neglecting the soil water status effect. The established coupled Pn,L-gm model also proved more effective in estimating gm than the previously proposed model. Introducing the two diffusion control functions into the whole-plant model, the developed model for WUEs,P effectively captured its response pattern to different Ca and SWC conditions. Overall, this study confirmed that the accurate estimation of WUEs,P requires an improved predictive accuracy of gsw and gm. These results have important implications for predicting how plants respond to climate change. Full article
(This article belongs to the Special Issue Stable Isotope in Soil, Plant and Water: Ecohydrological Process from Ecosystem to Watershed)
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21 pages, 5897 KiB  
Article
Enhancing Informed Decisions for Coastal Groundwater Sustainability: A Network Analysis of Water-Related Indicator Results from 122 Cities
by Khawon Lee, Sunwoo Chang, Stef Koop, Kees van Leeuwen and Jeryang Park
Water 2022, 14(2), 262; https://doi.org/10.3390/w14020262 - 17 Jan 2022
Cited by 3 | Viewed by 2292
Abstract
In many places around the globe, groundwater has been threatened by various pressures, which calls for better management strategies for groundwater sustainability. In this study, we suggest a novel framework for identifying factors critical to coastal groundwater based on results from City Blueprint [...] Read more.
In many places around the globe, groundwater has been threatened by various pressures, which calls for better management strategies for groundwater sustainability. In this study, we suggest a novel framework for identifying factors critical to coastal groundwater based on results from City Blueprint (CB) assessments. By compiling the 5856 indicator results of the City Blueprint Approach (CBA) from 122 cities and analyzing the correlation between these indicators, we constructed City Blueprint networks (CBN) by using a complex network modeling approach for three groups of cities: all 122 cities, 40 coastal, and 82 non-coastal cities. These networks were then analyzed for their node centralities to identify major factors that influence coastal groundwater management. Interestingly, our analysis revealed that groundwater has various indirect but important links with the factors that are typically unexplored in the literature. We also assessed the CB of the two largest coastal cities in South Korea. By combining the results of network analysis and CB assessment of the two cities, we could identify the indicators that are potentially at risk regarding coastal groundwater. We propose the CBN as a novel approach to unveil underestimated or hidden factors related to the target system (e.g., groundwater), which allows extensive options for sustainable groundwater management. Full article
(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)
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18 pages, 24787 KiB  
Article
Preparation of Magnetic Surface Ion-Imprinted Polymer Based on Functionalized Fe3O4 for Fast and Selective Adsorption of Cobalt Ions from Water
by Zijian Zhao, Hui Jiang, Lang Wu, Ning Yu, Zhengwei Luo and Wenhua Geng
Water 2022, 14(2), 261; https://doi.org/10.3390/w14020261 - 17 Jan 2022
Cited by 12 | Viewed by 2555
Abstract
A novel cobalt ion-imprinted polymer (Co(II)-MIIP) based on magnetic Fe3O4 nanoparticles was prepared by using Co(II) as the template ion, and bis(2-methacryloxyethyl) phosphate and glycylglycine as dual functional monomers. The fabricated material was analyzed by Fourier transform infrared spectroscopy, thermogravimetric [...] Read more.
A novel cobalt ion-imprinted polymer (Co(II)-MIIP) based on magnetic Fe3O4 nanoparticles was prepared by using Co(II) as the template ion, and bis(2-methacryloxyethyl) phosphate and glycylglycine as dual functional monomers. The fabricated material was analyzed by Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, X-ray diffraction, and vibrating sample magnetometer. The adsorption experiments with Co(II)-MIIP, found that the maximum adsorption capacity could reach 33.4 mg·g−1, while that of the non-imprinted polymer (Co(II)-NIP) was found to reach 15.7 mg·g−1. The adsorption equilibriums of Co(II)-MIIP and Co(II)-NIP was established within 20 min and 30 min, respectively. The adsorption process could be suitably described by the Langmuir isotherm model and the pseudo-second-order kinetics model. In binary mixtures of Co(II)/Fe(II), Co(II)/Cu(II), Co(II)/Mg(II), Co(II)/Zn(II), and Co(II)/Ni(II), the relative selectivity coefficients of Co(II)-MIIP toward Co(II)-NIP were 5.25, 4.05, 6.06, 11.81, and 4.48, respectively. The regeneration experiments indicated that through six adsorption–desorption cycles, the adsorption capacity of Co(II)-MIIP remained nearly 90%. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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15 pages, 1449 KiB  
Communication
The Suitability of Hybrid Fe0/Aggregate Filtration Systems for Water Treatment
by Ran Tao, Huichen Yang, Xuesong Cui, Minhui Xiao, Nadège Gatcha-Bandjun, Joseline Flore Kenmogne-Tchidjo, Mesia Lufingo, Bernard Konadu Amoah, Raoul Tepong-Tsindé, Arnaud Igor Ndé-Tchoupé, Marquise Touomo-Wouafo, Brice Donald Btatkeu-K, Willis Gwenzi, Rui Hu, Jean Bosco Tchatchueng, Hans Ruppert and Chicgoua Noubactep
Water 2022, 14(2), 260; https://doi.org/10.3390/w14020260 - 17 Jan 2022
Cited by 12 | Viewed by 2772
Abstract
Metallic iron (Fe0) corrosion under immersed conditions (Fe0/H2O system) has been used for water treatment for the past 170 years. Fe0 generates solid iron corrosion products (FeCPs) which are known to in situ coat the surface [...] Read more.
Metallic iron (Fe0) corrosion under immersed conditions (Fe0/H2O system) has been used for water treatment for the past 170 years. Fe0 generates solid iron corrosion products (FeCPs) which are known to in situ coat the surface of aggregates, including granular activated carbon (GAC), gravel, lapillus, manganese oxide (MnO2), pyrite (FeS2), and sand. While admixing Fe0 and reactive aggregates to build hybrid systems (e.g., Fe0/FeS2, Fe0/MnO2, Fe0/sand) for water treatment, it has been largely overlooked that these materials would experience reactivity loss upon coating. This communication clarifies the relationships between aggregate addition and the sustainability of Fe0/H2O filtration systems. It is shown that any enhanced contaminant removal efficiency in Fe0/aggregate/H2O systems relative to the Fe0/H2O system is related to the avoidance/delay of particle cementation by virtue of the non-expansive nature of the aggregates. The argument that aggregate addition sustains any reductive transformation of contaminants mediated by electrons from Fe0 is disproved by the evidence that Fe0/sand systems are equally more efficient than pure Fe0 systems. This demonstration corroborates the concept that aqueous contaminant removal in iron/water systems is not a process mediated by electrons from Fe0. This communication reiterates that only hybrid Fe0/H2O filtration systems are sustainable. Full article
(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)
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22 pages, 5858 KiB  
Article
Attribution of Changes in Streamflow to Climate Change and Land Cover Change in Yangtze River Source Region, China
by Naveed Ahmed, Genxu Wang, Haishen Lü, Martijn J. Booij, Hero Marhaento, Foyez Ahmed Prodhan, Shahid Ali and Muhammad Ali Imran
Water 2022, 14(2), 259; https://doi.org/10.3390/w14020259 - 17 Jan 2022
Cited by 18 | Viewed by 3389
Abstract
The quantitative attribution of changes in streamflow to climate change (CC) and land cover change (LCC) for the Yangtze River Source Region (YRSR), China, was assessed. We used a combination of the SWAT model along with the statistical technique one factor at a [...] Read more.
The quantitative attribution of changes in streamflow to climate change (CC) and land cover change (LCC) for the Yangtze River Source Region (YRSR), China, was assessed. We used a combination of the SWAT model along with the statistical technique one factor at a time (OFAT) and innovative trend analysis (ITA) to achieve the study objectives. The climate and hydrology data from 1961 to 2016 and land-cover maps of 5 years’ difference from 1985 to 2015 were used. The model was calibrated (1964–1989) using a land-cover map of 1985 and validated for 1990–2016. This validated model was further validated for all other land-cover maps used in this study. The SWAT model simulation showed that streamflow had been significantly influenced by CC compared to LCC using land-cover maps of 1985–1990, 1990–1995. However, the SWAT model simulations did not result in further changes in streamflow for land cover maps of 2000–2005, 2005–2010, and 2010–2015 because there have not been any significant changes in land cover after 2000 while the main contributing factor was climate change. The SWAT model simulations showed that the main driver of changes in streamflow in the Yangtze River Source Region is climate change. This study shows that the individual impacts are more critical than combined impacts for designing hydraulic structures, water resources planning and management, and decision-making policies at the regional/basin scale. Full article
(This article belongs to the Section Hydrology)
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16 pages, 2580 KiB  
Article
Flow Intermittency Affects Leaf Decomposition and Benthic Consumer Communities of Alpine Streams: A Case Study along the Po River
by Laura Gruppuso, Alberto Doretto, Elisa Falasco, Stefano Fenoglio, Michele Freppaz, Mark Eric Benbow and Francesca Bona
Water 2022, 14(2), 258; https://doi.org/10.3390/w14020258 - 16 Jan 2022
Cited by 6 | Viewed by 2868
Abstract
Streams and rivers are becoming increasingly intermittent in Alpine regions due to the global climate change and related increases of local water abstractions, making it fundamental to investigate the occurrence of supraseasonal drying events and their correlated effects. We aimed to investigate leaf [...] Read more.
Streams and rivers are becoming increasingly intermittent in Alpine regions due to the global climate change and related increases of local water abstractions, making it fundamental to investigate the occurrence of supraseasonal drying events and their correlated effects. We aimed to investigate leaf litter decomposition, the C:N ratio of the litter, and changes in associated macroinvertebrate communities in three reaches of the Po River: One upstream, consistently perennial, a perennial mid-reach with high hydrological variability, and an intermittent downstream reach. We placed leaf litter bags of two leaf types—chestnut and oak; both showed comparable decomposition rates, but the remaining litter mass was different and was attributed to the C:N ratio and palatability. Furthermore, (1) in perennial reaches, leaf litter decomposed faster than in the intermittent ones; (2) in intermittent reaches, the C:N ratio showed a decreasing trend in both leaf types, indicating that drying affected the nitrogen consumption, therefore the conditioning phase; (3) associated macroinvertebrate communities were richer and more stable in perennial reaches, where a higher richness and abundance of EPT taxa and shredders was observed. Our results suggest that the variations in the hydrology of mountain streams caused by global climate change could significantly impact on functional processes and biodiversity of benthic communities. Full article
(This article belongs to the Special Issue Effects of Climate Change on Freshwater Biodiversity)
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23 pages, 6458 KiB  
Article
Detecting the Quantitative Hydrological Response to Changes in Climate and Human Activities at Temporal and Spatial Scales in a Typical Gully Region of the Loess Plateau, China
by Peng Guo, Jiqiang Lyu, Weining Yuan, Xiawan Zhou, Shuhong Mo, Dengrui Mu and Pingping Luo
Water 2022, 14(2), 257; https://doi.org/10.3390/w14020257 - 16 Jan 2022
Cited by 7 | Viewed by 2267
Abstract
This study examined the Chabagou River watershed in the gully region of the Loess Plateau in China’s Shaanxi Province, and was based on measured precipitation and runoff data in the basin over a 52-year period (1959–2010), land-use types, normalized difference vegetation index (NDVI), [...] Read more.
This study examined the Chabagou River watershed in the gully region of the Loess Plateau in China’s Shaanxi Province, and was based on measured precipitation and runoff data in the basin over a 52-year period (1959–2010), land-use types, normalized difference vegetation index (NDVI), and other data. Statistical models and distributed hydrological models were used to explore the influences of climate change and human activity on the hydrological response and on the temporal and spatial evolution of the basin. It was found that precipitation and runoff in the gully region presented a downward trend during the 52-year period. Since the 1970s, the hydrological response to human activities has become the main source of regional hydrological evolution. Evapotranspiration from the large silt dam in the study area has increased. The depth of soil water decreased at first, then it increased by amount that exceeded the evaporation increase observed in the second and third change periods. The water and soil conservation measures had a beneficial effect on the ecology of the watershed. These results provide a reference for water resource management and soil and water conservation in the study area. Full article
(This article belongs to the Special Issue The Interrelationship between Climate Change, Human Activities and Hydrological Processes)
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29 pages, 6505 KiB  
Review
Review of a Semi-Empirical Modelling Approach for Cohesive Sediment Transport in River Systems
by Bommanna G. Krishnappan
Water 2022, 14(2), 256; https://doi.org/10.3390/w14020256 - 16 Jan 2022
Cited by 11 | Viewed by 3118
Abstract
In this paper, a review of a semi-empirical modelling approach for cohesive sediment transport in river systems is presented. The mathematical modelling of cohesive sediment transport is a challenge because of the number of governing parameters controlling the various transport processes involved in [...] Read more.
In this paper, a review of a semi-empirical modelling approach for cohesive sediment transport in river systems is presented. The mathematical modelling of cohesive sediment transport is a challenge because of the number of governing parameters controlling the various transport processes involved in cohesive sediment, and hence a semi-empirical approach is a viable option. A semi-empirical model of cohesive sediment called the RIVFLOC model developed by Krishnappan is reviewed and the model parameters that need to be determined using a rotating circular flume are highlighted. The parameters that were determined using a rotating circular flume during the application of the RIVFLOC model to different river systems include the critical shear stress for erosion of the cohesive sediment, critical shear stress for deposition according to the definition of Partheniades, critical shear stress for deposition according to the definition of Krone, the cohesion parameter governing the flocculation of cohesive sediment and a set of empirical parameters that define the density of the floc in terms of the size of the flocs. An examination of the variability of these parameters shows the need for testing site-specific sediments using a rotating circular flume to achieve a reliable prediction of the RIVFLOC model. Application of the model to various river systems has highlighted the need for including the entrapment process in a cohesive sediment transport model. Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
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16 pages, 5154 KiB  
Article
Groundwater Nitrate Pollution Sources Assessment for Contaminated Wellfield
by Marko Šrajbek, Lado Kranjčević, Ivan Kovač and Ranko Biondić
Water 2022, 14(2), 255; https://doi.org/10.3390/w14020255 - 16 Jan 2022
Cited by 15 | Viewed by 3736
Abstract
Nitrates are one of the most common groundwater contaminants and they come from different sources. The paper presents a study of groundwater quality at Varaždin wellfield in the north part of Croatia. The nitrate concentration at this location has been above the maximum [...] Read more.
Nitrates are one of the most common groundwater contaminants and they come from different sources. The paper presents a study of groundwater quality at Varaždin wellfield in the north part of Croatia. The nitrate concentration at this location has been above the maximum allowed concentration for several decades, which has made the opening of new wellfields costly. Based on the previously developed groundwater flow model, a model that covers the narrow area of the wellfield is developed. The influential zone of the observed wellfield in working conditions is determined. Based on the developed model, the sources of nitrate pollution are located, which can be generally divided into non-point and point sources. Considering the time of groundwater retention in the horizontal flow, it is concluded that the water protection zones are marked following the applicable ordinance. Based on the developed groundwater flow model at the observed wellfield, a simulation of nitrate pollution propagation by advection and dispersion processes is performed. The simulation results point out the location of the poultry landfill as the largest source of nitrate pollution. However, poultry farms, which are located in the influence area of the wellfield, also contribute significantly to the nitrate concentration at the wellfield. Full article
(This article belongs to the Special Issue Groundwater Vulnerability to Pollution Assessment)
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16 pages, 5871 KiB  
Article
Assessment of the Impact of Climate Extremes on the Groundwater of Eastern Croatia
by Marija Šperac and Jasna Zima
Water 2022, 14(2), 254; https://doi.org/10.3390/w14020254 - 16 Jan 2022
Cited by 2 | Viewed by 1888
Abstract
This paper analyzes the groundwater in the deep Quaternary aquifer of Eastern Croatia. These waters are collected at the Vinogradi Pumping Station (Osijek, Croatia) for the needs of public water supply. This research aimed to assess the impact of climate extremes, namely, high [...] Read more.
This paper analyzes the groundwater in the deep Quaternary aquifer of Eastern Croatia. These waters are collected at the Vinogradi Pumping Station (Osijek, Croatia) for the needs of public water supply. This research aimed to assess the impact of climate extremes, namely, high air temperatures and low rainfall, on the quantity and quality of groundwater. On the basis of data from the Vinogradi Pumping Station in the period 1987–2015, three extremely warm and low-water years were singled out. For these three years, the following were analyzed: climate diagrams, groundwater levels (in the piezometers closest to and farthest from the pumping station), and the quality of the affected groundwater. The results of this research indicate that the reaction of aquifers to the analyzed extreme climatic conditions for the observed period was manifested in the variation of the amplitude of groundwater levels by a maximum of 4–5 m. Considering the total thickness of the affected layers (60–80 m), this variation is not a concern from the point of view of water supply. As for the quality of groundwater, it was found to be of constant quality in its composition and was not affected by climatic extremes. Full article
(This article belongs to the Section Hydrology)
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23 pages, 7533 KiB  
Review
A Bibliometric Analysis of Drought Indices, Risk, and Forecast as Components of Drought Early Warning Systems
by Gokhan Yildirim, Ataur Rahman and Vijay P. Singh
Water 2022, 14(2), 253; https://doi.org/10.3390/w14020253 - 16 Jan 2022
Cited by 15 | Viewed by 4196
Abstract
In this study, we apply a bibliometric analysis to characterize publication data on droughts, mainly focusing on drought indices (DIs), drought risk (DR), and drought forecast (DF). Data on publications on these selected topics were obtained through the Scopus database, covering the period [...] Read more.
In this study, we apply a bibliometric analysis to characterize publication data on droughts, mainly focusing on drought indices (DIs), drought risk (DR), and drought forecast (DF). Data on publications on these selected topics were obtained through the Scopus database, covering the period from 1963 to June 2021. The DI-related publications, based on meteorological, soil moisture, hydrological, remote sensing, and composite/modeled Dis, accounted for 57%, 8%, 4%, 29%, and 2% of the scientific sources, respectively. DI-related studies showed a notable increase since the 1990s, due perhaps to a higher number of major droughts during the last three decades. It was found that USA and China were the two leading countries in terms of publication count and academic influence on the DI, DR, and DF studies. A network analysis of the country of residence of co-authors on DR and DF research highlighted the top three countries, which were the USA, China, and the United Kingdom. The most productive journal for the DI studies was found to be the International Journal of Climatology, whereas Natural Hazards was identified as the first-ranked journal for the DR and DF studies. In relation to individual researchers, Singh VP from the USA was found to be the most prolific author, having the greatest academic influence on DF study, whereas Zhang Q from China was identified as the most productive author on DR study. This bibliometric analysis reveals that further research is needed on droughts in the areas of risk management, water management, and drought management. This review maps trends of previous research in drought science, covering several important aspects, such as drought indices, geographic regions, authors and their collaboration paths, and sub-topics of interest. This article is expected to serve as an index of the current state of knowledge on drought warning systems and as guidance for future research needs. Full article
(This article belongs to the Special Issue Sustainable Water Futures: Climate, Community and Circular Economy)
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11 pages, 1943 KiB  
Article
Isotopic Composition of Glacier Ice and Meltwater in the Arid Parts of the Altai Mountains (Central Asia)
by Dmitriy Bantcev, Dmitriy Ganyushkin, Anton Terekhov, Alexey Ekaykin, Igor Tokarev and Kirill Chistyakov
Water 2022, 14(2), 252; https://doi.org/10.3390/w14020252 - 16 Jan 2022
Cited by 5 | Viewed by 2361
Abstract
The objective of this study is to reveal the isotopic composition of ice and meltwater in glaciated regions of South-Eastern Altai. The paper depicts differences between the isotopic composition of glacier ice from several types of glaciers and from various locations. Detected differences [...] Read more.
The objective of this study is to reveal the isotopic composition of ice and meltwater in glaciated regions of South-Eastern Altai. The paper depicts differences between the isotopic composition of glacier ice from several types of glaciers and from various locations. Detected differences between the isotopic composition of glacier ice in diversified parts of the study region are related to local climate patterns. Isotopic composition of meltwater and isotopic separation for glacier rivers runoff showed that in the Tavan-Bogd massif, seasonal snow participates more in the formation of glacier runoff due to better conditions for snow accumulation on the surface of glaciers. In other research areas pure glacier meltwater prevails in runoff. Full article
(This article belongs to the Special Issue Use of Water Isotopes in Hydrological Processes II)
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20 pages, 5189 KiB  
Article
Responses of Bacterial Taxonomical Diversity Indicators to Pollutant Loadings in Experimental Wetland Microcosms
by Subhomita Ghosh Roy, Charles F. Wimpee, S. Andrew McGuire and Timothy J. Ehlinger
Water 2022, 14(2), 251; https://doi.org/10.3390/w14020251 - 16 Jan 2022
Cited by 4 | Viewed by 3460
Abstract
Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients into surface waters. This directly impacts organisms in aquatic ecosystems, including microbes. Sediment microbes are known for pollution reduction in the face of contamination, making bacterial communities an important area [...] Read more.
Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients into surface waters. This directly impacts organisms in aquatic ecosystems, including microbes. Sediment microbes are known for pollution reduction in the face of contamination, making bacterial communities an important area for bioindicator research. This study explores the pattern of bacterial responses to metal and nutrient pollution loading and seeks to evaluate whether bacterial indicators can be effective as a biomonitoring risk assessment tool for wetland ecosystems. Microcosms were built containing sediments collected from wetlands in the urbanizing Pike River watershed in southeastern Wisconsin, USA, with metals and nutrients added at 7 day intervals. Bacterial DNA was extracted from the microcosm sediments, and taxonomical profiles of bacterial communities were identified up to the genera level by sequencing 16S bacterial rRNA gene (V3–V4 region). Reduction of metals (example: 90% for Pb) and nutrients (example: 98% for NO3−) added in water were observed. The study found correlations between diversity indices of genera with metal and nutrient pollution as well as identified specific genera (including Fusibacter, Aeromonas, Arthrobacter, Bacillus, Bdellovibrio, and Chlorobium) as predictive bioindicators for ecological risk assessment for metal pollution. Full article
(This article belongs to the Special Issue Constructed Wetlands for Water Pollution Control in Urban and Rural Areas)
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13 pages, 2180 KiB  
Article
A Simulation Analysis of a Microalgal-Production Plant for the Transformation of Inland-Fisheries Wastewater in Sustainable Feed
by Janet B. García-Martínez, Jefferson E. Contreras-Ropero, Néstor A. Urbina-Suarez, Germán L. López-Barrera, Andrés F. Barajas-Solano, Viatcheslav Kafarov, Crisóstomo Barajas-Ferreira, Diana M. Ibarra-Mojica and Antonio Zuorro
Water 2022, 14(2), 250; https://doi.org/10.3390/w14020250 - 16 Jan 2022
Cited by 6 | Viewed by 3421
Abstract
The present research evaluates the simulation of a system for transforming inland-fisheries wastewater into sustainable fish feed using Designer® software. The data required were obtained from the experimental cultivation of Chlorella sp. in wastewater supplemented with N and P. According to the [...] Read more.
The present research evaluates the simulation of a system for transforming inland-fisheries wastewater into sustainable fish feed using Designer® software. The data required were obtained from the experimental cultivation of Chlorella sp. in wastewater supplemented with N and P. According to the results, it is possible to produce up to 11,875 kg/year (31.3 kg/d) with a production cost of up to 18 (USD/kg) for dry biomass and 0.19 (USD/bottle) for concentrated biomass. Similarly, it was possible to establish the kinetics of growth of substrate-dependent biomass with a maximum production of 1.25 g/L after 15 days and 98% removal of available N coupled with 20% of P. It is essential to note the final production efficiency may vary depending on uncontrollable variables such as climate and quality of wastewater, among others. Full article
(This article belongs to the Section Water Use and Scarcity)
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12 pages, 2243 KiB  
Article
Evaluation of Soil Water Content Using SWAT for Southern Saskatchewan, Canada
by Mohammad Zare, Shahid Azam and David Sauchyn
Water 2022, 14(2), 249; https://doi.org/10.3390/w14020249 - 15 Jan 2022
Cited by 17 | Viewed by 3910
Abstract
Soil water content (SWC) is one of the most important hydrologic variables; it plays a decisive role in the control of various land surface processes. We simulated SWC using a Soil and Water Assessment Tool (SWAT) model in southern Saskatchewan. SWC was calibrated [...] Read more.
Soil water content (SWC) is one of the most important hydrologic variables; it plays a decisive role in the control of various land surface processes. We simulated SWC using a Soil and Water Assessment Tool (SWAT) model in southern Saskatchewan. SWC was calibrated using measured data and Soil Moisture Active Passive (SMAP) Level-4 for the surface (0–5 cm) SWC for hydrological response units (HRU) at daily and monthly (warm season) intervals for the years 2015 to 2020. We used the SUFI-2 technique in SWAT-CUP, and observed daily instrumented streamflow records, for calibration (1995 to 2004) and validation (2005–2010). The results reveal that the SWAT model performs well with a monthly PBIAS < 10% and Nash–Sutcliffe efficiency (NS) and R2 ≥ 0.8 for calibration and validation. The correlation coefficient between ground measurement with SMAP and SWAT products are 0.698 and 0.633, respectively. Moreover, SMAP data of surface SWC coincides well with measurements in terms of both amount and trend compared with the SWAT product. The highest r value occurred in July when the mean r value in SWAT and SMAP were 0.87 to 0.84, and then in June for r value of 0.75. In contrast, the lowest values were in April and May (0.07 and 0.04, respectively) at the beginning of the growing season in southern Saskatchewan. Furthermore, calibration in the SWAT model is based on a batch form whereby parameters are adjusted to corresponding input by modifying simulations with observations. SWAT underestimates the abrupt increase in streamflow during the snowmelt months (April and May). This study achieved the objective of developing a SWAT model that simulates SWC in a prairie watershed, and, therefore, can be used in a subsequent phase of research to estimate future soil moisture conditions under projected climate changes. Full article
(This article belongs to the Section Soil and Water)
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12 pages, 4517 KiB  
Article
A Modified AVI Model for Groundwater Vulnerability Mapping: Case Studies in Southern Italy
by Daniela Ducci and Mariangela Sellerino
Water 2022, 14(2), 248; https://doi.org/10.3390/w14020248 - 15 Jan 2022
Cited by 10 | Viewed by 2942
Abstract
Many methods for evaluating the aquifer’s vulnerability to pollution have been developed in the past four decades by using geographic information system (GIS) tools. However, even if the aquifer vulnerability concept is well defined and the methods have been constantly tested and compared, [...] Read more.
Many methods for evaluating the aquifer’s vulnerability to pollution have been developed in the past four decades by using geographic information system (GIS) tools. However, even if the aquifer vulnerability concept is well defined and the methods have been constantly tested and compared, the problem of the choice of the best “standard” method remains. To meet these objectives, aquifer vulnerability maps are of crucial importance. The choice of method depends on several factors, including the scale of the project, the hydrogeological characteristics of the area, and data availability. Among the many methods, the AVI (Aquifer Vulnerability Index) method has been widely used as it considers only two physical parameters. The AVI Index represents the hydraulic resistance of an aquifer to vertical flow, as a ratio between the thickness of each sedimentary unit above the uppermost aquifer (D, length), and the estimated hydraulic conductivity (K, length/time) of each of these layers. The AVI Index has a time dimension and is divided into five classes. In order to avoid a widespread presence of the higher vulnerability classes, especially in shallow aquifers, the AVI classification has been modified using statistical methods. The study reports the application of the modified AVI method for groundwater pollution vulnerability, in three different areas of southern Italy, highlighting the limitations of the method in alluvial aquifers and the differences with other methods. Full article
(This article belongs to the Special Issue Groundwater Vulnerability to Pollution Assessment)
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17 pages, 288 KiB  
Article
An Analysis of Household Perceptions of Water Costs across the United States: A Survey Based Approach
by Laura Medwid and Elizabeth A. Mack
Water 2022, 14(2), 247; https://doi.org/10.3390/w14020247 - 15 Jan 2022
Cited by 1 | Viewed by 3408
Abstract
Research analyzing perceptions of water services has focused on water quality, water safety, and the propensity to consume water from different sources. It has not assessed perceptions of water costs. To address this knowledge gap, this study collected nationally representative survey data from [...] Read more.
Research analyzing perceptions of water services has focused on water quality, water safety, and the propensity to consume water from different sources. It has not assessed perceptions of water costs. To address this knowledge gap, this study collected nationally representative survey data from households in the United States about water issues and incorporated these data into logistic regression models. In doing so, our study advances the water and public policy literature in three ways. One, it addresses the need for household resolution information about water issues given the absence of data at this scale in the United States. Two, it creates and utilizes one-of-a-kind survey data to understand the perceptions of household water bills and the drivers of these perceptions. Three, we assess the impact of proposed solutions to improve water affordability on household perceptions of water costs. Model results indicate low-income and households in underrepresented groups were more likely to perceive their water bills to be too high. The perception of water costs also varied geographically. From a policy perspective, model results indicate utilities can positively affect perceptions of water bills via the frequency of water billing and provision of payment assistance programs. Full article
(This article belongs to the Topic Water Management in the Era of Climatic Change)
16 pages, 3713 KiB  
Article
How to Implement User-Friendly BLMs in the Absence of DOC Monitoring Data: A Case Study on Bulgarian Surface Waters
by Tony Venelinov and Stefan Tsakovski
Water 2022, 14(2), 246; https://doi.org/10.3390/w14020246 - 15 Jan 2022
Cited by 4 | Viewed by 1870
Abstract
The metal bioavailability concept is implemented in the Water Framework Directive (WFD) compliance assessment. The bioavailability assessment is usually performed by the application of user-friendly Biotic Ligand Models (BLMs), which require dissolved metal concentrations to be used with the “matching” data of the [...] Read more.
The metal bioavailability concept is implemented in the Water Framework Directive (WFD) compliance assessment. The bioavailability assessment is usually performed by the application of user-friendly Biotic Ligand Models (BLMs), which require dissolved metal concentrations to be used with the “matching” data of the supporting physicochemical parameters of dissolved organic carbon (DOC), pH and Cadissolved. Many national surface water monitoring networks do not have sufficient matching data records, especially for DOC. In this study, different approaches for dealing with the missing DOC data are presented: substitution using historical data; the appropriate percentile of DOC concentrations; and combinations of the two. The applicability of the three following proposed substitution approaches is verified by comparison with the available matching data: (i) calculations from available TOC data; (ii) the 25th percentile of the joint Bulgarian monitoring network DOC data (measured and calculated by TOC); and (iii) the 25th percentile of the calculated DOC from the matching TOC data for the investigated surface water body (SWB). The application of user-friendly BLMs (BIO-MET, M-BAT and PNEC Pro) to 13 surface water bodies (3 reservoirs and 10 rivers) in the Bulgarian surface waters monitoring network outlines that the suitability of the substitution approaches decreases in order: DOC calculated by TOC > the use of the 25th percentile of the data for respective SWB > the use of the 25th percentile of the Bulgarian monitoring network data. Additionally, BIO-MET is the most appropriate tool for the bioavailability assessment of Cu, Zn and Pb in Bulgarian surface water bodies. Full article
(This article belongs to the Special Issue Insights into Organic Carbon, Iron, Metals and Phosphorus Dynamics in Freshwaters)
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14 pages, 3197 KiB  
Article
Arsenic Accumulation and Biotransformation Affected by Nutrients (N and P) in Common Blooming-Forming Microcystis wesenbergii (Komárek) Komárek ex Komárek (Cyanobacteria)
by Zhe Xiao, Xiaochuang Li and Shouliang Huo
Water 2022, 14(2), 245; https://doi.org/10.3390/w14020245 - 15 Jan 2022
Cited by 2 | Viewed by 2000
Abstract
Arsenic accumulation and biotransformation in algae was mostly carried out in a medium that contained far higher nutrient concentrations than that in natural freshwaters. The obtained results might have limited environmental validity and result in a failure to describe authentic arsenic biogeochemical cycles [...] Read more.
Arsenic accumulation and biotransformation in algae was mostly carried out in a medium that contained far higher nutrient concentrations than that in natural freshwaters. The obtained results might have limited environmental validity and result in a failure to describe authentic arsenic biogeochemical cycles in natural freshwater systems. To validate the assumption, arsenic accumulation, and biotransformation in common bloom forming Microcystis wesenbergii was performed under a high nutrient concentration in BG11 medium (N = 250 mg/L, P = 7.13 mg/L), and adjusted low nutrients that mimicked values in natural freshwaters (N = 1.5 mg/L, P = 0.3 mg/L). The growth rate and maximum M. wesenbergii cell density were much lower in the high nutrient set, but more inhibition was shown with increasing ambient iAs(V) concentrations both in the high and low nutrient sets. The proportion of intracellular contents in total arsenicals decreased with increasing iAs(V) concentrations in both high and low nutrient sets but increased with incubation time. Intracellular iAs(III) was not found in the high nutrient set, while it formed high concentrations that could be comparable to that of an extracellular level in the low nutrient set. M. wesenbergii could methylate arsenic, and a higher proportion of organoarsenicals was formed in the low nutrient set. Lower intracellular MMA(V) and DMA(V) concentrations were found in the high nutrient set; contrarily, they presented a higher concentration that could be comparable to the extracellular ones in the low nutrient set. The results demonstrated that different nutrient regimes could affect arsenic accumulation and biotransformation in M. wesenbergii, and low nutrient concentrations could inhibit the excretion of iAs(III), MMA(V) and DMA(V) out of cells. Further investigations should be based on natural freshwater systems to obtain an authentic arsenic accumulation and biotransformation in cyanobacteria. Full article
(This article belongs to the Special Issue Transforming Process and Flux of Nutrients and Trace Metals at Sediment–Water Interface)
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20 pages, 12880 KiB  
Article
Application of Artificial Neural Networks for Mangrove Mapping Using Multi-Temporal and Multi-Source Remote Sensing Imagery
by Arsalan Ghorbanian, Seyed Ali Ahmadi, Meisam Amani, Ali Mohammadzadeh and Sadegh Jamali
Water 2022, 14(2), 244; https://doi.org/10.3390/w14020244 - 15 Jan 2022
Cited by 23 | Viewed by 4960
Abstract
Mangroves, as unique coastal wetlands with numerous benefits, are endangered mainly due to the coupled effects of anthropogenic activities and climate change. Therefore, acquiring reliable and up-to-date information about these ecosystems is vital for their conservation and sustainable blue carbon development. In this [...] Read more.
Mangroves, as unique coastal wetlands with numerous benefits, are endangered mainly due to the coupled effects of anthropogenic activities and climate change. Therefore, acquiring reliable and up-to-date information about these ecosystems is vital for their conservation and sustainable blue carbon development. In this regard, the joint use of remote sensing data and machine learning algorithms can assist in producing accurate mangrove ecosystem maps. This study investigated the potential of artificial neural networks (ANNs) with different topologies and specifications for mangrove classification in Iran. To this end, multi-temporal synthetic aperture radar (SAR) and multi-spectral remote sensing data from Sentinel-1 and Sentinel-2 were processed in the Google Earth Engine (GEE) cloud computing platform. Afterward, the ANN topologies and specifications considering the number of layers and neurons, learning algorithm, type of activation function, and learning rate were examined for mangrove ecosystem mapping. The results indicated that an ANN model with four hidden layers, 36 neurons in each layer, adaptive moment estimation (Adam) learning algorithm, rectified linear unit (Relu) activation function, and the learning rate of 0.001 produced the most accurate mangrove ecosystem map (F-score = 0.97). Further analysis revealed that although ANN models were subjected to accuracy decline when a limited number of training samples were used, they still resulted in satisfactory results. Additionally, it was observed that ANN models had a high resistance when training samples included wrong labels, and only the ANN model with the Adam learning algorithm produced an accurate mangrove ecosystem map when no data standardization was performed. Moreover, further investigations showed the higher potential of multi-temporal and multi-source remote sensing data compared to single-source and mono-temporal (e.g., single season) for accurate mangrove ecosystem mapping. Overall, the high potential of the proposed method, along with utilizing open-access satellite images and big-geo data processing platforms (i.e., GEE, Google Colab, and scikit-learn), made the proposed approach efficient and applicable over other study areas for all interested users. Full article
(This article belongs to the Special Issue Mapping and Monitoring of Wetlands)
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15 pages, 888 KiB  
Article
SWOT-SOR Analysis of Activated Carbon-Based Technologies and O3/UV Process as Polishing Treatments for Hospital Effluent
by Vittoria Grillini, Paola Verlicchi and Giacomo Zanni
Water 2022, 14(2), 243; https://doi.org/10.3390/w14020243 - 14 Jan 2022
Cited by 5 | Viewed by 3219
Abstract
The management and treatment of hospital wastewater are issues of great concern worldwide. Both in the case of a dedicated treatment or co-treatment with urban wastewater, hospital effluent is generally subjected to pre-treatments followed by a biological step. A polishing treatment is suggested [...] Read more.
The management and treatment of hospital wastewater are issues of great concern worldwide. Both in the case of a dedicated treatment or co-treatment with urban wastewater, hospital effluent is generally subjected to pre-treatments followed by a biological step. A polishing treatment is suggested to promote (and guarantee) the removal of micropollutants still present and to reduce the total pollutant load released. Activated carbon-based technologies and advanced oxidation processes have been widely investigated from technical and economic viewpoints and applied in many cases. In this study, the potential exploitation of these technologies for the polishing treatment of hospital effluent is investigated by combining a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis with a Strategic Orientation (SOR) analysis. This approach allows a coherent strategy to be extracted from the SWOT-SOR data, increasing the chances of success of each technology. It emerges that both technologies present relevant and sometimes similar strengths and can present opportunities. At the same time, activated carbon-based technologies are more likely to contain the main identified threats than O3/UV technology. The study also finds that, for both technologies, further research and development could improve their potential applications in the treatment of hospital wastewater. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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