Special Issue "Environmental Chemistry of Water Quality Monitoring"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Aquatic Systems—Quality and Contamination".

Deadline for manuscript submissions: closed (1 September 2020).

Special Issue Editor

Prof. Dr. Martha J.M. Wells
Website1 Website2
Guest Editor
EnviroChem Services, Cookeville, Tennessee, USA
Interests: analytical/environmental/medicinal chemistry; separation science; water quality; pesticides; pharmaceutical and personal care products; endocrine disrupting chemicals; nanoparticles; humic/fulvic acids; EEM-PARAFAC

Special Issue Information

Dear Colleagues,

The world's water supply is a precious commodity that circulates in a continuous cycle of use, abuse, and reuse—we all live downstream. Chemical water quality monitoring data lead to assessments and management of this valuable resource. For this Special Issue in Water, manuscripts (research, reviews, short communications) are solicited that describe data-gathering by sampling and analyses of chemical constituents in all types of environmental water bodies over time and space, whether impacted by natural or anthropogenic sources. Beyond merely reporting monitoring data, manuscripts are expected to interpret results of water quality monitoring studies within the context of environmental chemistry principles by evaluating such issues as chemical character, sources and sinks, fate and transport, or other potential impacts of chemicals on our water supply.

Prof. Dr. Martha J.M. Wells
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Environmental aquatic chemistry
  • Water quality monitoring
  • Built (engineered) and natural aquatic environments
  • Chemical occurrence
  • Water pollution
  • Legacy and emerging contaminants
  • Chemical transformation processes and products

Published Papers (18 papers)

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Research

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Open AccessArticle
Investigating the Status of Cadmium, Chromium and Lead in the Drinking Water Supply Chain to Ensure Drinking Water Quality in Malaysia
Water 2020, 12(10), 2653; https://doi.org/10.3390/w12102653 - 23 Sep 2020
Abstract
Prolonged persistence of toxic cadmium (Cd), chromium (Cr) and lead (Pb) in the aquatic environment are due to its nonbiodegradable characteristic. A few studies have reported higher concentrations of these metals in the transboundary Langat River, Malaysia. This study determined the spatial and [...] Read more.
Prolonged persistence of toxic cadmium (Cd), chromium (Cr) and lead (Pb) in the aquatic environment are due to its nonbiodegradable characteristic. A few studies have reported higher concentrations of these metals in the transboundary Langat River, Malaysia. This study determined the spatial and temporal distributions of Cd, Cr and Pb concentrations (2005–2015) in the Langat River along with assessing the status of these metals in the drinking water supply chain at the basin. Water samples were collected once in 2015 from the drinking water supply chain, i.e., from the river, treated water at plants, taps and filtration water at households. Determined mean concentrations of Cd, Cr and Pb by inductively coupled plasma mass spectrometry in the Langat River were within the drinking water quality standard of Malaysia and the WHO, except for the Pb (9.99 ± 1.40 µg/L) concentration, which was at the maximum limit, 10 µg/L. The spatial and temporal distribution of these metals’ concentrations indicate dilution of it downstream, along with the increasing trend in rainfall and water flow, especially during the northeast monsoon. Significant correlation and regression analysis of the Cd, Cr and Pb concentrations also indicate that the sources of this metal pollution are mainly the natural weathering of minerals along with anthropogenic activities in the basin. The determined overall water quality of the Langat River is categorized Class IIA (i.e., clean), which requires conventional treatment before drinking; however, the maximum removal efficiency of these metals by the plants at the basin was about 90.17%. Therefore, the proactive leadership roles of the local authorities will be appropriate to reduce the pollution of this river as well as introducing a two-layer water filtration system at the Langat River Basin to accelerate the achievement of a sustainable drinking water supply. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Proposal for Water Quality Improvement by Using an Innovative and Comprehensive Restoration Method
Water 2020, 12(9), 2377; https://doi.org/10.3390/w12092377 - 25 Aug 2020
Abstract
This study was conducted on Miłkowskie Lake (23.7 ha; 15.0 m) in the context of implementing new restoration methods for improving the water quality. The study found that the nutrient loads introduced into the lake from catchment are higher than the critical concentrations [...] Read more.
This study was conducted on Miłkowskie Lake (23.7 ha; 15.0 m) in the context of implementing new restoration methods for improving the water quality. The study found that the nutrient loads introduced into the lake from catchment are higher than the critical concentrations for the ecosystem. This indicates the need to cut off or at least reduce the main sources of pollution. The primary production in the lake is extremely large: oxygen saturation of the surface water above 200%, pH value of 9.44, chlorophyll a content of 70.98 mg m−3, and a low visibility of 0.5 m. The most important step in maintaining good lake quality will be to redirect waters of the main inflows SI-1 and SI-2 to the hypolimnion zone by pipelines. A complementary method for discharging the polluted water to the hypolimnion zone will be the phosphorus inactivation method by using iron and aluminum coagulants. After the application of spring doses of coagulants, an anti-cyanobacterial preparation will be introduced into the water in the “active bottom” zone, and then bioremediation by a microbiological probiotic preparation will be applied to the sediment in the same zone. A new complex protection and restoration method should be supported in the form of biomanipulation. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Seasonal and Diurnal Variation of Air/Water Exchange of Gaseous Mercury in a Southern Reservoir Lake (Cane Creek Lake, Tennessee, USA)
Water 2020, 12(8), 2102; https://doi.org/10.3390/w12082102 - 24 Jul 2020
Abstract
A year-long field study of mercury (Hg) air/water exchange was conducted at a southern reservoir lake, Cane Creek Lake (Cookeville, TN, USA). The Hg air/water exchange fluxes and meteorological data including solar radiation (global solar radiation, Rg and ultraviolent radiation, UVA), water [...] Read more.
A year-long field study of mercury (Hg) air/water exchange was conducted at a southern reservoir lake, Cane Creek Lake (Cookeville, TN, USA). The Hg air/water exchange fluxes and meteorological data including solar radiation (global solar radiation, Rg and ultraviolent radiation, UVA), water and air temperatures, relative humidity, and wind speed were collected to study the daily and seasonal trends of the Hg air/water exchange at the lake in relation to solar radiation and wind speed. The Hg exchange fluxes generally exhibited diurnal patterns with a rise in the morning, a peak around noontime, and a fall in the afternoon through the evening, closely following the change of solar radiation. There were cases that deviated from this general daily trend. The Hg emission fluxes were all below 3 ng m−2 h−1 with the daily mean fluxes < 2 ng m−2 h−1. The fluxes in the summer (mean: 1.2 ng m−2 h−1) were higher than in the fall (mean: 0.6 ng m−2 h−1) and winter (mean: 0.7 ng m−2 h−1). The daily and seasonal trends of the Hg air/water exchange fluxes are similar to the trends of the changes of the dissolved gaseous mercury (DGM) concentrations in the lake observed in our previous study. Solar radiation was found to exert a primary control over the Hg air/water exchange, while wind speed appeared to have a secondary effect on the Hg exchange. The two-thin-film model was used to calculate Hg emission fluxes from the Cane Creek Lake water. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Towards Monitoring of Nutrient Pollution in Coastal Lake Using Remote Sensing and Regression Analysis
Water 2020, 12(7), 1954; https://doi.org/10.3390/w12071954 - 09 Jul 2020
Abstract
The last few decades have witnessed a tremendous increase in nutrient levels (phosphorus and nitrogen) in coastal water leading to excessive algal growth (Eutrophication). The presence of large amounts of algae turns the water’s color into green or red, in the case of [...] Read more.
The last few decades have witnessed a tremendous increase in nutrient levels (phosphorus and nitrogen) in coastal water leading to excessive algal growth (Eutrophication). The presence of large amounts of algae turns the water’s color into green or red, in the case of algal blooms. Chlorophyll-a is often used as an indicator of algal biomass. Due to increased human activities surrounding Dubai creek, there have been eutrophication concerns given the levels of nutrients in that creek. This study aims to map chlorophyll-a in Dubai Creek from WorldView-2 imagery and explore the relationship between chlorophyll-a and other eutrophication indicators. A geometrically- and atmospherically-corrected WorldView-2 image and in-situ data have been utilized to map chlorophyll-a in the creek. A spectral model, developed from the WorldView-2 multispectral image to monitor Chlorophyll-a concentration, yielded 0.82 R2 with interpolated in-situ chlorophyll-a data. To address the time lag between the in-situ data and the image, Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images were used to demonstrate the accuracy of the WorldView-2 model. The images, acquired on 20 May and 23 July 2012, were processed to extract chlorophyll-a band ratios (Band 4/Band 3) following the standard approach. Based on the availability, the 20 May image acquisition date is the closest to the middle of Quarter 2 (Q2) of the in-situ data (15 May). The 23 July 2012 image acquisition date is the closest to the WorldView-2 image date (24 July). Another model developed to highlight the relationship between spectral chlorophyll-a levels, and total nitrogen and orthophosphate levels, yielded 0.97 R2, which indicates high agreement. Furthermore, the generated models were found to be useful in mapping chlorophyll-a, total nitrogen, and orthophosphate, without the need for costly in-situ data acquisition efforts. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
A Regional Difference Analysis of Microplastic Pollution in Global Freshwater Bodies Based on a Regression Model
Water 2020, 12(7), 1889; https://doi.org/10.3390/w12071889 - 02 Jul 2020
Abstract
Based on statistical data of the average abundance of microplastics from 37 global freshwater locations up to November 2019, we classified the freshwater bodies according to developments in their local countries and geographic positions. We highlighted the differences and causes of microplastic pollution [...] Read more.
Based on statistical data of the average abundance of microplastics from 37 global freshwater locations up to November 2019, we classified the freshwater bodies according to developments in their local countries and geographic positions. We highlighted the differences and causes of microplastic pollution in the waters of both developed and developing countries and urban and rural areas. The results showed that microplastic pollution was highest in Asia. The pollution in developed countries was significantly lower than in developing countries. The differences in freshwater pollution between urban and rural areas mainly depended on the extent of human activity. The present study found the following phenomena by comprehensively using simple and multiple regression models and a Pearson correlation analysis to solve the impacts of the features, natural factors, and social and economic factors on the distribution of microplastic pollution. The density of microplastics was higher, which promoted the aggregation of microplastics in sediments. Pursuant to that, microplastic pollution was also influenced by the space-time pollution of movable surface sources, such as the soil and air. A population increase and the average gross domestic product (GDP) could also worsen microplastic pollution. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Quantification and Speciation of Trace Metals under Pollution Impact: Case Study of a Subarctic Lake
Water 2020, 12(6), 1641; https://doi.org/10.3390/w12061641 - 08 Jun 2020
Abstract
Monitoring the quantity and quality of metals in lake water is a major part of assessing water toxicity. A fundamental aspect of geochemical monitoring studies is the evaluation of the equilibrium distribution of metal speciation in water and the influence of environmental conditions [...] Read more.
Monitoring the quantity and quality of metals in lake water is a major part of assessing water toxicity. A fundamental aspect of geochemical monitoring studies is the evaluation of the equilibrium distribution of metal speciation in water and the influence of environmental conditions on this process. It is important to understand the difference between the behavior of nanoparticles, dissolved particles, colloid particles, and suspended particles. This study involved environmental aquatic chemistry research and the assessment of the geochemical processes of metal speciation in an arctic lake in the metallurgical waste zone and other areas where natural processes prevail. Consecutive and parallel membrane filtration methods were used to compare the results of water analysis in Imandra Lake. The membrane pore sizes were 8, 1.2, 0.45, and 0.2 µm. The following filtrate characteristics were used: microfiltration-based mechanical suspension and oxidized contaminants (>8, 1.2, 0.45, 0.2, 0.1 μm), and ultrafiltration-based colloids, bacteria, viruses, etc. (less than 0.1 μm). Industrial effluents led to the formation of higher concentrations of elements (Ni, Cu, and Pb) in their labile forms. In the wastewater-mixing zone, the concentrations of most elements were evenly distributed in depth. In more distant areas, we found a significant increase in the concentration of elements in the near-bottom horizon in comparison with the surface water (Fe by more than three times). The obtained results showed that numerous elements had diverse distributions by speciation in the points located closer to the source of wastewater. This indicated the significant influence of the adsorption process on the system balance of elements such as Fe, Cu, and rare earth elements. The impact of the regional geochemical and anthropogenic speciation and the possible influence of climatic factors on the distribution of speciation were determined. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Assessment of Water Buffer Capacity of Two Morphometrically Different, Degraded, Urban Lakes
Water 2020, 12(5), 1512; https://doi.org/10.3390/w12051512 - 25 May 2020
Abstract
The research was conducted in Karczemne Lake (area, 40.4 ha; maximum (max.) depth, 3.2 m) and Klasztorne Małe Lake (area, 13.7 ha; max. depth, 20.0 m) located in the Kashubian Lake District (Northern Poland). From the beginning of the 1950s, these reservoirs have [...] Read more.
The research was conducted in Karczemne Lake (area, 40.4 ha; maximum (max.) depth, 3.2 m) and Klasztorne Małe Lake (area, 13.7 ha; max. depth, 20.0 m) located in the Kashubian Lake District (Northern Poland). From the beginning of the 1950s, these reservoirs have received municipal and storm wastewater. The long-term process of lake contamination has shaped the specific buffer capacity conditions and influenced the circulation of carbonate and bicarbonate in the water of these ecosystems. Extremely high concentrations of nutrients (Karczemne Lake: max. total phosphorous (TP) level, 7.5 mg P L−1; max. total nitrogen (TN) level, 5.6 mg N L−1; Klasztorne Małe Lake: max. TP level, 20.6 mg P L−1; max. TN level, 43.3 mg N L−1) have caused very intensive primary production processes (Karczemne Lake: max. chlorophyll-a level, 193.40 µg m−3; max. Secchi disc visibility, 0.85 m; Klasztorne Małe Lake: max. chlorophyll-a level, 160.01 µg m−3; max. Secchi disc visibility, 1.15 m). In the polymictic Karczemne Lake, the pH value of all water columns exceeded 10.0 (max. pH, 10.41), and in the meromictic Klasztorne Małe Lake, the pH of the surface water layers oscillated around 9.5. In the polymictic Karczemne Lake, despite intensive photosynthesis, the calcium content and alkalinity were similar throughout the whole water column due to constant circulation. In the meromictic Klasztorne Małe Lake, during the growing season, a decrease in calcium concentration and alkalinity of the surface water layers and an increase in calcium concentration at the bottom were noted. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Hydrochemical Characteristics and Ion Sources of Precipitation in the Upper Reaches of the Shiyang River, China
Water 2020, 12(5), 1442; https://doi.org/10.3390/w12051442 - 19 May 2020
Abstract
The Shiyang River Basin is located at the edge of the monsoon wind system of South and Southeast Asia. The hydrochemical characteristics of precipitation are influenced by both monsoon and arid regions. The regression analysis method, comparative analysis, neutralization factor (NF), enrichment factor [...] Read more.
The Shiyang River Basin is located at the edge of the monsoon wind system of South and Southeast Asia. The hydrochemical characteristics of precipitation are influenced by both monsoon and arid regions. The regression analysis method, comparative analysis, neutralization factor (NF), enrichment factor (EF) and HYSPLIT4 were used to analyze the precipitation samples collected from the upper reaches of the Shiyang River from October 2016 to October 2017. In order to study the hydrochemical characteristics and ion sources of precipitation in this basin. The results, as discussed in this paper, show that the precipitation in the upper reaches of the Shiyang River is mildly alkaline all year round while the neutralization ability of Ca2+ and NH4+ in precipitation is strong. The ion concentration was higher in the dry season than that in the wet season, but the concentration of NH4+ was higher in summer. Furthermore, as the altitude increased, the electrical conductivity (EC) of the precipitation decreased gradually. Influenced by precipitation and rainy days, the wet deposition of nitrogen (N) and sulfur (S) was higher in the wet season than that during the dry season, and the wet deposition gradually increased with the elevation. In precipitation, the earth’s crust is a major source of Ca2+, K+ and Mg2+, the ocean is a major source of Cl, the ocean and the earth’s crust are the sources of Na+, human activities are the main sources of SO42−, NO3 and NH4+, the amount of F is very small, its sources are natural and human activities. Water vapor in precipitation mainly comes from westerly air mass circulation and monsoon circulation while the particles come mainly from the earth’s crust. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Countrywide Groundwater Quality Trend and Suitability for Use in Key Sectors of Korea
Water 2020, 12(4), 1193; https://doi.org/10.3390/w12041193 - 22 Apr 2020
Cited by 3
Abstract
Under changing climate, increasing groundwater use has risen the concern for groundwater quality variations over recent years, to maintain a healthy ecosystem. The objectives were to identify trend of temporal variations in groundwater quality and its suitability for different uses in Republic of [...] Read more.
Under changing climate, increasing groundwater use has risen the concern for groundwater quality variations over recent years, to maintain a healthy ecosystem. The objectives were to identify trend of temporal variations in groundwater quality and its suitability for different uses in Republic of Korea. Water quality data were collected from 198 monitoring stations of Groundwater Quality Monitoring Network (GQMN), annually for the period of ten years (2008–2017). Non-parametric trend analysis of a Mann–Kendall test and Theil–Sen’s slope was done on groundwater physico-chemical data of ten years. Groundwater suitability evaluation was done for use in main sectors including domestic (drinking) and agriculture (irrigation). For drinking suitability analysis, results were compared with World Health Organization (WHO) and Korean Ministry of Environment (KME) established guidelines. For irrigation suitability evaluation, electrical conductivity (EC), Sodium Adsorption Ratio (SAR), percent of Na+, Residual Sodium Carbonate (RSC), US Salinity Laboratory (USSL), and Wilcox diagram were used. Most significantly, water type belongs to Ca-HCO3 and Ca-SO4 types, but a small proportion belongs to Na-CO3 and Na-Cl types. Approximately, 96% and 93% of groundwater samples are suitable for drinking, based on WHO and KME guidelines, respectively. Around 98% and 83% of groundwater samples are in suitable range for irrigation use, based on USSL and Wilcox diagrams, respectively. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Contamination Profiles of Perfluoroalkyl Substances (PFAS) in Groundwater in the Alluvial–Pluvial Plain of Hutuo River, China
Water 2019, 11(11), 2316; https://doi.org/10.3390/w11112316 - 06 Nov 2019
Cited by 3
Abstract
Over the past decade, concerns about perfluoroalkyl substances (PFAS) have increased rapidly among the scientific community due to their global distribution and persistence in various environmental matrices. The occurrences of 10 PFAS in groundwater in the alluvial–pluvial plain of Hutuo River (APPHR) in [...] Read more.
Over the past decade, concerns about perfluoroalkyl substances (PFAS) have increased rapidly among the scientific community due to their global distribution and persistence in various environmental matrices. The occurrences of 10 PFAS in groundwater in the alluvial–pluvial plain of Hutuo River (APPHR) in the North China Plain (NCP) were analyzed via UPLC-MS/MS and solid phase extraction. Total PFAS concentrations ranged from 0.56 ng/L to 13.34 ng/L, with an average value of 2.35 ng/L. Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) were dominant PFAS contaminants with high detection rates of 98.39% and 95.16%, respectively, and PFOA was the main pollutant with a mean concentration of 0.65 ng/L. The hydrogeological conditions have an important influence on the concentrations of PFAS in groundwater. Comparatively, the concentration of PFAS in groundwater in the study area is not very high, but it reflects that the groundwater in this region is affected by industrial sources to some extent. Local government should pay more attention on industrial pollution control and groundwater protection in this area. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Efficient Water Quality Prediction Using Supervised Machine Learning
Water 2019, 11(11), 2210; https://doi.org/10.3390/w11112210 - 24 Oct 2019
Cited by 9
Abstract
Water makes up about 70% of the earth’s surface and is one of the most important sources vital to sustaining life. Rapid urbanization and industrialization have led to a deterioration of water quality at an alarming rate, resulting in harrowing diseases. Water quality [...] Read more.
Water makes up about 70% of the earth’s surface and is one of the most important sources vital to sustaining life. Rapid urbanization and industrialization have led to a deterioration of water quality at an alarming rate, resulting in harrowing diseases. Water quality has been conventionally estimated through expensive and time-consuming lab and statistical analyses, which render the contemporary notion of real-time monitoring moot. The alarming consequences of poor water quality necessitate an alternative method, which is quicker and inexpensive. With this motivation, this research explores a series of supervised machine learning algorithms to estimate the water quality index (WQI), which is a singular index to describe the general quality of water, and the water quality class (WQC), which is a distinctive class defined on the basis of the WQI. The proposed methodology employs four input parameters, namely, temperature, turbidity, pH and total dissolved solids. Of all the employed algorithms, gradient boosting, with a learning rate of 0.1 and polynomial regression, with a degree of 2, predict the WQI most efficiently, having a mean absolute error (MAE) of 1.9642 and 2.7273, respectively. Whereas multi-layer perceptron (MLP), with a configuration of (3, 7), classifies the WQC most efficiently, with an accuracy of 0.8507. The proposed methodology achieves reasonable accuracy using a minimal number of parameters to validate the possibility of its use in real time water quality detection systems. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Controlling Factors of Surface Water Ionic Composition Characteristics in the Lake Genggahai Catchment, NE Qinghai–Tibetan Plateau, China
Water 2019, 11(7), 1329; https://doi.org/10.3390/w11071329 - 27 Jun 2019
Abstract
This study has determined the major ion compositions of surface waters within the basin of Lake Genggahai, northeastern Qinghai–Tibetan Plateau, China. The results showed that the anions in the groundwater and river water of Genggahai Lake are mainly HCO3, and [...] Read more.
This study has determined the major ion compositions of surface waters within the basin of Lake Genggahai, northeastern Qinghai–Tibetan Plateau, China. The results showed that the anions in the groundwater and river water of Genggahai Lake are mainly HCO3, and the cations are mainly Ca2+ + Na+. Evaporite, carbonate, and silicate in the basin all have an impact on the chemical composition of river water and groundwater. Among them, carbonate weathering has a relatively larger contribution. The grazing activities of herdsmen in the basin have had a certain degree of impact on the water quality of river basins and groundwater. The anion of lake water is dominated by Cl, and the cation is mainly Na+. The content change is mainly affected by the change of corresponding ion content in groundwater coming into the lake and the evaporation of lake water. Among them, Cl in lake water is more affected by the change of Cl content in the groundwater coming into the lake, while Na+ in lake water is more affected by evaporation. More specifically, the low concentrations of Ca2+ and HCO3 in lake water were determined to be related to the photosynthesis of aquatic plants in the lake. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
A Revised Method of Surface Water Quality Evaluation Based on Background Values and Its Application to Samples Collected in Heilongjiang Province, China
Water 2019, 11(5), 1057; https://doi.org/10.3390/w11051057 - 21 May 2019
Cited by 5
Abstract
In China, the use of certain standards to evaluate surface water quality in areas with high background values due to natural factors rather than to human activities results in water quality underestimation and thus affects regional water quality management and decision-making. Herein, we [...] Read more.
In China, the use of certain standards to evaluate surface water quality in areas with high background values due to natural factors rather than to human activities results in water quality underestimation and thus affects regional water quality management and decision-making. Herein, we examined river source water function zones of the Heilongjang province characterised by high background values and analysed the corresponding water quality data acquired in 2011–2016. The examined samples featured elevated chemical oxygen demand (COD), permanganate index (CODMn), and ammonia nitrogen (NH3-N) levels, which indicated that water quality was affected by the natural environment. The concentrations of background pollutants almost exceeded the limits stipulated by regional surface water quality standards and exhibited strong spatiotemporal variability. A three-step discrimination method including single index recognition, limiting factors, and a synthetic index was proposed to distinguish the background area among these zones for determining background values, and 10 complete background areas were identified. The background values of COD, CODMn, and NH3-N for the entire area were determined based on the data acquired during background area monitoring. Finally, considering the present procedure of water quality evaluation in China (single factor exponential method), a revised method based on background values was suggested. Thus, the evaluation results objectively and accurately reflect the regional water quality situation and therefore provide a scientific basis for the development of a better water quality assessment and management system in China. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Groundwater Quality Assessment in a Volcanic Mountain Range (South of Gran Canaria Island, Spain)
Water 2019, 11(4), 754; https://doi.org/10.3390/w11040754 - 11 Apr 2019
Cited by 4
Abstract
The lack of rainfall in the Canary Islands′ Archipelago is leading to the depletion of the existing aquifers throughout the islands, above all in the easternmost isles (Gran Canaria, Lanzarote and Fuerteventura). Due to the increasing water demand in the southern area of [...] Read more.
The lack of rainfall in the Canary Islands′ Archipelago is leading to the depletion of the existing aquifers throughout the islands, above all in the easternmost isles (Gran Canaria, Lanzarote and Fuerteventura). Due to the increasing water demand in the southern area of the Island of Gran Canaria, appropriate planning has become necessary in order to avoid the depletion of the phreatic water resources that can be found there. One of the most affected areas is the Amurga Mountain Range, where the existing aquifers are depleted, as shown in the Hydrological Plan of Gran Canaria. The aim of this study was to characterize the hydrochemistry of the above-mentioned groundwater bodies. Water quality monitoring was carried out over a period of five years, involving the survey of a total of 288 samples (over 4300 tests). The water from those aquifers has the characteristic of being fairly mineralized, with a prevalence of Cl, Ca2+ and Na+ ions, salinity levels reaching 8646 mg/L, and chloride levels up to 4200 mg/L. The waters of these aquifers can be divided into two basic types, i.e., those containing high levels of sodium chloride, which can be found around the Tirajana Gorge; and the waters rich in magnesium chloride and sodium sulfate in the Arguineguín Gorge, as well as in the Amurga Massif itself. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Spatial and Temporal Variation of Dissolved Heavy Metals in the Mun River, Northeast Thailand
Water 2019, 11(2), 380; https://doi.org/10.3390/w11020380 - 22 Feb 2019
Cited by 9
Abstract
River water samples between August 2017 (wet season) and March 2018 (dry season) from the Mun River Basin in northeast Thailand were collected and their dissolved heavy metals concentrations (Al, Mn, Fe, Cu, Zn, and Ba) were measured. Compared with international drinking water [...] Read more.
River water samples between August 2017 (wet season) and March 2018 (dry season) from the Mun River Basin in northeast Thailand were collected and their dissolved heavy metals concentrations (Al, Mn, Fe, Cu, Zn, and Ba) were measured. Compared with international drinking water guidelines, Mn was the dominant pollutant in the dry season. The correlation analysis (CA) suggested that similar sources were shown in each element pair of Al-Fe, Mn-Zn, and Fe-Ba in both seasons. The principal component analysis (PCA) results showed that the dominant source of dissolved heavy metals was sedimentary inputs or colloid destabilization in the wet season, while anthropogenic inputs were the main sources in the dry season, such as agricultural runoff, industrial effluents, and domestic discharge. On the basis of water quality index (WQI), water at most sites in the wet and dry seasons can be categorized as excellent water, except for a few sites with substandard values. The river water posed no significant health risks according to the health risk assessment, but Mn, Fe, and Ba needed to be paid more attention due to the relatively high values. Al, Fe, and Ba were the main dissolved heavy metals flowing into the Mekong River, and Cu contributed to the background value in the Mekong river. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
Spatial and Seasonal Distribution and Transportation of Different Forms of Phosphorus in the Middle Reaches of the Yarlung Zangbo River
Water 2018, 10(12), 1858; https://doi.org/10.3390/w10121858 - 14 Dec 2018
Cited by 4
Abstract
The Yarlung Zangbo River basin ecosystem is fragile. The distribution and transportation of phosphorus is of great significance for aquatic environmental protection and ecological security. The sequential extraction method and molybdenum antimony anti-spectrophotometry were used to measure the concentrations of different forms of [...] Read more.
The Yarlung Zangbo River basin ecosystem is fragile. The distribution and transportation of phosphorus is of great significance for aquatic environmental protection and ecological security. The sequential extraction method and molybdenum antimony anti-spectrophotometry were used to measure the concentrations of different forms of phosphorus in the surface sediments from 15 sampling sites along the middle reaches of the Yarlung Zangbo River and its tributaries. The results show that the total phosphorus concentration in the surface sediments is 194.0~540.7 mg/kg, which is mainly composed of inorganic phosphorus. The concentrations of various phosphorus forms ranked as calcium-bound phosphorus (355.6 ± 86.0 mg/kg) > soluble phosphorus (15.9 ± 10.0 mg/kg) > iron-bound phosphorus (12.4 ± 12.3 mg/kg) > organic phosphorus (9.6 ± 6.1 mg/kg) > occluded phosphorus (9.2 ± 3.8 mg/kg) > aluminum-bound phosphorus (5.4 ± 2.3 mg/kg). On the whole, phosphorus concentration is greater in wet season than dry season. Regarding the spatial distribution characteristics, there are great disparities in the different forms of phosphorus in the middle reaches of the Yarlung Zangbo River. Comprehensive analysis shows that phosphorus of this area is mainly self-generated, and concentration of bioavailable phosphorus is small, demonstrating there will not be a large release. We also drew a “specific triangle” of the different forms of phosphorus concentrations in the research area and defined the “α” angle to determine the nutrient status of the overlying water quickly and effectively. Finally, phosphorus flux of the mainstream was estimated. This research may provide information on the phosphorus of Plateau Rivers. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Open AccessArticle
The Influence of Karst Aquifer Mineralogy and Geochemistry on Groundwater Characteristics: West Bank, Palestine
Water 2018, 10(12), 1829; https://doi.org/10.3390/w10121829 - 11 Dec 2018
Cited by 4
Abstract
This work reports, for the first time, the mineralogical and geochemical characteristics of karst aquifers in the Central West Bank (CWB) catchment in Palestine. It provides an integrated study approach by correlating the geochemistry of the lithology and hydrochemical data of groundwater samples. [...] Read more.
This work reports, for the first time, the mineralogical and geochemical characteristics of karst aquifers in the Central West Bank (CWB) catchment in Palestine. It provides an integrated study approach by correlating the geochemistry of the lithology and hydrochemical data of groundwater samples. Mineralogical analysis showed that all of the samples were dominantly composed of either calcite CaCO3 (5–100 wt. %) or dolomite CaMg(CO3)2 (4–100 wt. %), with minor amounts of quartz and feldspar, which is supported by the inorganic carbon content (9–13 wt. %) and hydrochemical composition of the spring water samples. The whole-rock geochemical data indicated that the samples have low contents of trace elements and transition metals. In contrast, the concentrations of alkaline earth elements (Mg, Ca, Sr, Ba) and Mn were high in the rock and groundwater samples. Generally, the trace elements of rock samples with concentrations >10 ppm included Sr (17–330 ppm), Mn (17–367 ppm), Ba (2–32 ppm), W (5–37 ppm), Cr (3–23 ppm), Zn (1.7–28 ppm), V (4–23 ppm), and Zr (1–22 ppm), while the concentrations of all the other trace elements was below 10 ppm. Ionic ratios and hierarchical cluster analysis (HCA) suggested that the chemical evolution of groundwater was mainly related to the geogenic (rock–water) interaction in the study area. This is clear in the alkaline earth elements (Mg, Ca, Sr, Ba) ratios, especially regarding the Sr values. The calcite rock samples had higher Sr (mean 160 ppm, n = 11) than those of the dolomite rocks (mean 76 ppm, n = 9). Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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Review

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Open AccessReview
Recent Advancements in the Removal of Cyanotoxins from Water Using Conventional and Modified Adsorbents—A Contemporary Review
Water 2020, 12(10), 2756; https://doi.org/10.3390/w12102756 - 03 Oct 2020
Abstract
The prevalence of cyanobacteria is increasing in freshwaters due to climate change, eutrophication, and their ability to adapt and thrive in changing environmental conditions. In response to various environmental pressures, they produce toxins known as cyanotoxins, which impair water quality significantly. Prolonged human [...] Read more.
The prevalence of cyanobacteria is increasing in freshwaters due to climate change, eutrophication, and their ability to adapt and thrive in changing environmental conditions. In response to various environmental pressures, they produce toxins known as cyanotoxins, which impair water quality significantly. Prolonged human exposure to cyanotoxins, such as microcystins, cylindrospermopsin, saxitoxins, and anatoxin through drinking water can cause severe health effects. Conventional water treatment processes are not effective in removing these cyanotoxins in water and advanced water treatment processes are often used instead. Among the advanced water treatment methods, adsorption is advantageous compared to other methods because of its affordability and design simplicity for cyanotoxins removal. This article provides a current review of recent developments in cyanotoxin removal using both conventional and modified adsorbents. Given the different cyanotoxins removal capacities and cost of conventional and modified adsorbents, a future outlook, as well as suggestions are provided to achieve optimal cyanotoxin removal through adsorption. Full article
(This article belongs to the Special Issue Environmental Chemistry of Water Quality Monitoring)
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