Special Issue "Soil and groundwater resources: sustainable management, pollution prevention, and remediation"

A special issue of International Journal of Environmental Research and Public Health (ISSN 1660-4601). This special issue belongs to the section "Environmental Science and Engineering".

Deadline for manuscript submissions: 31 December 2019.

Special Issue Editors

Dr. Deyi Hou
E-Mail Website
Guest Editor
Tsinghua University, School of Environment, Beijing, China
Interests: innovative and green materials including biochar, nano-materials, and controlled release materials; sustainable remediation technologies; contaminant fate and transport in porous media; sustainability assessment and environmental policy
Dr. Zhengtao Shen
E-Mail Website
Guest Editor
University of Alberta, Department of Earth and Atmospheric Sciences, Edmonton, Canada
Interests: interactions between biochar and trace elements; soil amendment with green and sustainable materials; soil stabilization/solidification with novel binders; long-term effectiveness of soil remediation
Dr. Fei Wang
E-Mail Website
Guest Editor
Southeast University, School of Transportation, Nanjing, China
Interests: remediation of contaminated lands using solidification/stabilization;remediation of contaminated groundwater using permeable reactive barrier; ground improvement; the migration characteristics of pollutants in soil and groundwater

Special Issue Information

Dear Colleagues,

Soil and groundwater are precious non-renewable resources in the terrestrial system. They are also important factors of productivity in human society. Historical anthropogenic activities have caused wide-spread contamination of soil and groundwater. When such soil and groundwater come into contact with human beings, toxic chemicals, such as heavy metals, pesticides, and other organic pollutants, they can be absorbed by the body through dermal contact, ingestion, and inhalation, leading to severe human health problems. In the United States (US), it is estimated that approximately 294,000 contaminated sites require clean up (USEPA, 2004); in Europe, the European Environmental Agency (EEA) estimated that EEA member countries have 2.5 million potentially contaminated sites (EEA, 2014); in China, a national soil quality survey suggested that approximately 16.1% of the nation's land was polluted (MEP, 2014). To achieve sustainable development goals, precious soil and groundwater resources must be managed in a sustainable way. Pollution prevention needs to become a prerequisite of economic development. For land areas that have been contaminated, proper risk management measures need to be in place; and, for seriously contaminated sites, remediation should be conducted to alleviate human health and environmental risks. The sustainable management, pollution prevention, and remediation of soil and groundwater represent important research directions.

For this Special Issue we invite submissions that explore the sustainable management of groundwater resources, methodologies to reduce pesticide and fertilizer usage and to increase productivity in agricultural soil, pollution sources and abatement measures, contaminant fate and transport, spatial distribution and temporal trend of heavy metals and organic pollutants, contaminated site investigation, risk management, remediation of contaminates soil and/or groundwater, long-term management, and optimization. Studies linking science with policy are also welcome.

Dr. Deyi Hou
Dr. Zhengtao Shen
Dr. Fei Wang
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 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

  • Groundwater resource
  • soil productivity
  • contaminated soil
  • contaminated groundwater
  • pollution prevention
  • remediation
  • sustainability
  • heavy metal
  • organic pollutant
  • treatment

Published Papers (19 papers)

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Research

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Open AccessArticle
Effects of Soil Aggregate Stability on Soil Organic Carbon and Nitrogen under Land Use Change in an Erodible Region in Southwest China
Int. J. Environ. Res. Public Health 2019, 16(20), 3809; https://doi.org/10.3390/ijerph16203809 - 10 Oct 2019
Abstract
Soil aggregate stability can indicate soil quality, and affects soil organic carbon (SOC) and soil organic nitrogen (SON) sequestration. However, for erodible soils, the effects of soil aggregate stability on SOC and SON under land use change are not well known. In this [...] Read more.
Soil aggregate stability can indicate soil quality, and affects soil organic carbon (SOC) and soil organic nitrogen (SON) sequestration. However, for erodible soils, the effects of soil aggregate stability on SOC and SON under land use change are not well known. In this study, soil aggregate distribution, SOC and SON content, soil aggregate stability, and soil erodibility were determined in the soils at different depths along the stages following agricultural abandonment, including cropland, abandoned cropland, and native vegetation land in an erodible region of Southwest China. Soil aggregation, soil aggregate stability, and SOC and SON content in the 0–20 cm depth soils increased after agricultural abandonment, but soil texture and soil erodibility were not affected by land use change. Soil erodibility remained in a low level when SOC contents were over 20 g·kg−1, and it significantly increased with the loss of soil organic matter (SOM). The SOC and SON contents increased with soil aggregate stability. This study suggests that rapidly recovered soil aggregate stability after agricultural abandonment promotes SOM sequestration, whereas sufficient SOM can effectively maintain soil quality in karst ecological restoration. Full article
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Open AccessArticle
Cd, Cu, and Zn Accumulations Caused by Long-Term Fertilization in Greenhouse Soils and Their Potential Risk Assessment
Int. J. Environ. Res. Public Health 2019, 16(15), 2805; https://doi.org/10.3390/ijerph16152805 - 06 Aug 2019
Abstract
The intense management practices in greenhouse production may lead to heavy metal (HM) accumulations in soils. To determine the accumulation characteristics of HM and to evaluate possible HM sources in greenhouse soils, thirty typical greenhouse soil samples were collected in Shouguang District, Shandong [...] Read more.
The intense management practices in greenhouse production may lead to heavy metal (HM) accumulations in soils. To determine the accumulation characteristics of HM and to evaluate possible HM sources in greenhouse soils, thirty typical greenhouse soil samples were collected in Shouguang District, Shandong Province, China. The results indicate that the Cd, Cu, and Zn concentrations are, respectively, 164.8%, 78.6%, and 123.9% higher than their background values. In the study area, Cd exhibits certain characteristics, such as wide variations in the proportion of its exchangeable form and the highest mobility factor and geo-accumulation index, which are indicative of its high bioavailability and environmental risk. In addition, there is a significant positive correlation between pairs of Cd, P, soil organic carbon, and cultivation age. Combined with principal component analysis, the results indicate the clear effects that agricultural activities have on Cd, Cu, and Zn accumulation. However, Cr, Ni, and Pb have a significant correlation with soil Fe and Al (hydr)-oxides, which indicates that these metals mainly originate from parent materials. This research indicated that long-term intensive fertilization (especially the application of chemical fertilizers and livestock manure) leads to Cd, Cu, and Zn accumulation in greenhouse soils in Shouguang. And the time required to reach the maximum permeable limit in agricultural soils for Cd, Cu, and Zn is 23, 51, and 42 years, respectively, based on their current increasing rates. Full article
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Open AccessArticle
In Situ Persulfate Oxidation of 1,2,3-Trichloropropane in Groundwater of North China Plain
Int. J. Environ. Res. Public Health 2019, 16(15), 2752; https://doi.org/10.3390/ijerph16152752 - 01 Aug 2019
Abstract
In situ injection of Fe(II)-activated persulfate was carried out to oxidize chlorinated hydrocarbons and benzene, toluene, ethylbenzene, and xylene (BTEX) in groundwater in a contaminated site in North China Plain. To confirm the degradation of contaminants, an oxidant mixture of persulfate, ferrous sulfate, [...] Read more.
In situ injection of Fe(II)-activated persulfate was carried out to oxidize chlorinated hydrocarbons and benzene, toluene, ethylbenzene, and xylene (BTEX) in groundwater in a contaminated site in North China Plain. To confirm the degradation of contaminants, an oxidant mixture of persulfate, ferrous sulfate, and citric acid was mixed with the main contaminants including 1,2,3-trichloropropane (TCP) and benzene before field demonstration. Then the mixed oxidant solution of 6 m3 was injected into an aquifer with two different depths of 8 and 15 m to oxidize a high concentration of TCP, other kinds of chlorinated hydrocarbons, and BTEX. In laboratory tests, the removal efficiency of TCP reached 61.4% in 24 h without other contaminants but the removal rate was decreased by the presence of benzene. Organic matter also reduced the TCP degradation rate and the removal efficiency was only 8.3% in 24 h. In the field test, as the solution was injected, the oxidation reaction occurred immediately, accompanied by a sharp increase of oxidation–reduction potential (ORP) and a decrease in pH. Though the concentration of pollutants increased due to the dissolution of non-aqueous phase liquid (NAPL) at the initial stage, BTEX could still be effectively degraded in subsequent time by persulfate in both aquifers, and their removal efficiency approached 100%. However, chlorinated hydrocarbon was relatively difficult to degrade, especially TCP, which had a relatively higher initial concentration, only had a removal efficiency of 30%–45% at different aquifers and monitoring wells. These finding are important for the development of injection technology for chlorinated hydrocarbon and BTEX contaminated site remediation. Full article
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Open AccessArticle
Effect of Pyrochar and Hydrochar on Water Evaporation in Clayey Soil under Greenhouse Cultivation
Int. J. Environ. Res. Public Health 2019, 16(14), 2580; https://doi.org/10.3390/ijerph16142580 - 19 Jul 2019
Abstract
Greenhouse cultivation consumes large volumes of freshwater, and excessive irrigation induces environmental problems, such as nutrient leaching and secondary salinization. Pyrochar (biochar from high-temperature pyrolysis) is an effective soil amendment, and researches have shown that pyrochar application could maintain soil nutrient and enhance [...] Read more.
Greenhouse cultivation consumes large volumes of freshwater, and excessive irrigation induces environmental problems, such as nutrient leaching and secondary salinization. Pyrochar (biochar from high-temperature pyrolysis) is an effective soil amendment, and researches have shown that pyrochar application could maintain soil nutrient and enhance carbon sequestration. In addition to pyrochar from pyrolysis, hydrochar from hydrothermic carbonization is considered as a new type of biochar and has the advantages of low energy consumption and a high productive rate. However, the effect of these two biochars on water evaporation in clayey soils under a greenhouse system has seldom been studied. The relationship between water evaporation and biochar properties is still unknown. Thus, in the present study, water evaporation under pyrochar and hydrochar application were recorded. Results showed that both pyrochar and hydrochar application could inhibit water evaporation in clayey soil under greenhouse cultivation. Pyrochar showed a better inhibition effect compared with hydrochar. Correlation analysis indicated that the water evaporation rate was significantly positively correlated with bulk density of biochar (p < 0.05). Overall, application of pyrochar or hydrochar could both reduce soil bulk density and inhibit soil evaporation, and be available for greenhouse cultivation. However, the inhibition effect depends on the properties of the biochar. Full article
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Open AccessArticle
Rapid Sequestration of Ecosystem Carbon in 30-year Reforestation with Mixed Species in Dry Hot Valley of the Jinsha River
Int. J. Environ. Res. Public Health 2019, 16(11), 1937; https://doi.org/10.3390/ijerph16111937 - 31 May 2019
Abstract
Reforestation plays an important role in the carbon cycle and climate change. However, knowledge of ecosystem carbon sequestration through reforestation with mixed species is limited. Especially in dry hot valley of the Jinsha River, no studies cover total ecosystem carbon sequestration level in [...] Read more.
Reforestation plays an important role in the carbon cycle and climate change. However, knowledge of ecosystem carbon sequestration through reforestation with mixed species is limited. Especially in dry hot valley of the Jinsha River, no studies cover total ecosystem carbon sequestration level in mature mixed plantations for a limited area of mixed plantations and difficulty in the sampling of plant roots and deep soil. In this study, carbon sequestration of seven mixed plantations of different ages in dry hot valley of the Jinsha River was investigated with analogous sites method. The results are as follows: 1) Deep soil organic carbon (SOC) storage significantly increased with stand age (p = 0.025), possibly due to fine root exudates and dissolved organic carbon transportation into deep soil and retention. 2) Total biomass carbon storage in the 30-year-old mixed plantation was 77.78 t C ha−1, 54 times reference wasteland and 9 times reference natural recovery shrub-grassland. However, total biomass carbon storage of 30-year-old mixed plantation was insignificantly lower than that of reference natural forest (p = 0.429). After 30 years of reforestation, plantation biomass carbon storage recovered to reference level, and its sequestration rate was 2.54 t C ha−1 yr−1. 3) The total ecosystem carbon storage of 30-year-old mixed plantation was 185.50 t C ha−1, 2.38 times reference wasteland, 2.29 times reference natural recovery shrub grassland, and 29% lower than reference natural forest. It indicated that niche complementary, good stand structure, and characteristics of dominant species Leucaena leucocephala in mixed plantations facilitate more rapid carbon sequestration, especially biomass carbon in the dry hot valley. Full article
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Open AccessArticle
Asymmetric Soil Warming under Global Climate Change
Int. J. Environ. Res. Public Health 2019, 16(9), 1504; https://doi.org/10.3390/ijerph16091504 - 28 Apr 2019
Cited by 1
Abstract
Daily surface soil temperature data from 360 weather stations in China during 1962–2011 were retrieved and analyzed. The data revealed two aspects of asymmetric soil warming. Firstly, there was asymmetry between day and night in terms of increases in soil temperature. The daily [...] Read more.
Daily surface soil temperature data from 360 weather stations in China during 1962–2011 were retrieved and analyzed. The data revealed two aspects of asymmetric soil warming. Firstly, there was asymmetry between day and night in terms of increases in soil temperature. The daily maximum surface soil temperature ( S T max ) and daily minimum surface soil temperature ( S T min ) increased at rates of 0.031 and 0.055 °C/year over the 50-year interval, respectively. As a consequence of the more rapid increases in S T min , the soil diurnal temperature range (SDTR) decreased at most stations (average rate of –0.025 °C/year), with the most profound decrease in winter (–0.08 °C/year). The solar duration (SD) was positively related to SDTR and is regarded as the key underlying cause of the decreasing SDTR. Secondly, there was asymmetry between the soil and air in the temperature increase. The differences between soil and air temperature ( T D ) were highest in summer (2.76 °C) and smallest in winter (1.55 °C), which decreased by 0.3 °C over the study interval, this meant agricultural practice plans based on air temperature alone may be severely limited. The difference between soil temperature and air temperature reduces at night. This would facilitate the wintering of perennials in areas near the zero-contour line. Full article
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Open AccessArticle
Insights into Heavy Metals Leakage in Chelator-Induced Phytoextraction of Pb- and Tl-Contaminated Soil
Int. J. Environ. Res. Public Health 2019, 16(8), 1328; https://doi.org/10.3390/ijerph16081328 - 12 Apr 2019
Abstract
Chelators including DTPA (diethylene triamine pentaacetic acid) and oxalic acid were selected for inducing phytoextraction of heavy metals (HMs) from Pb-, Tl-, and Pb-Tl- contaminated soil, in which heavy metals leakage was highly remarkable. Results showed that compared with the control group without [...] Read more.
Chelators including DTPA (diethylene triamine pentaacetic acid) and oxalic acid were selected for inducing phytoextraction of heavy metals (HMs) from Pb-, Tl-, and Pb-Tl- contaminated soil, in which heavy metals leakage was highly remarkable. Results showed that compared with the control group without chelating agent under planting conditions, the extraction efficiency (i.e., uptake coefficient) of Pb, Tl increased by 86%, 43% from Pb-Tl- contaminated soil in the presence of oxalic acid, and there was no significant change in heavy metal leakage under rainfall conditions. It was the best phytoremediation scheme in this work. Under rainfall conditions, the HMs concentration in the leachate showed a linear decreasing trend. Acid rain promoted the leakage of heavy metals, and the average leached amount of Tl increased by 1.47 times under acid rain conditions. However, for Pb, DTPA was the main influencing factor, followed by acid rain. Full article
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Open AccessArticle
The Influence of Ionic and Nonionic Surfactants on the Colloidal Stability and Removal of CuO Nanoparticles from Water by Chemical Coagulation
Int. J. Environ. Res. Public Health 2019, 16(7), 1260; https://doi.org/10.3390/ijerph16071260 - 09 Apr 2019
Abstract
The widespread use of copper oxide nanoparticles (CuO NPs) and surfactants in various consumer products makes it likely that they coexist in aqueous environments, making it important to study the effects of surfactants on the fate and transport behavior of CuO NPs. The [...] Read more.
The widespread use of copper oxide nanoparticles (CuO NPs) and surfactants in various consumer products makes it likely that they coexist in aqueous environments, making it important to study the effects of surfactants on the fate and transport behavior of CuO NPs. The present study aims to investigate the influence of anionic sodium lauryl sulfate (SLS) and nonionic nonylphenol ethoxylate (NPEO, Tergitol NP-9), on CuO NPs adsorption, aggregation, and removal from water by the coagulation process. The result of the sorption study indicates that both surfactants could be adsorbed on the surface of CuO NPs, and that SLS remarkably decreases the ζ potential as well as the hydrodynamic diameter (HDD) of CuO as compared to NP-9. The kinetic aggregation study showed that both SLS and NP-9 reduced the HDD of CuO NPs and retarded the settling rates at surfactant concentrations above 0.015% (w:v) over a 24 h-period. Moreover, enhanced aggregation of CuO NPs was observed in two environmental waters as compared to pure water, which could be related to their high ionic strength. The addition of surfactants in natural waters has been shown to reduce the aggregation and sedimentation of CuO; however, the reductive effect of SLS was more pronounced than that of NP-9. Finally, the coagulation results showed that the removal efficiencies of CuO, Cu2+, and the surfactant in all tested waters at optimum ferric chloride dosage reached around 98, 95, and 85%, respectively. Furthermore, the coagulation mechanism revealed that the combination of charge neutralization and adsorptive micellar flocculation (AMF) might be involved in the removal of both pollutants. The results of the present study provide new insight into the environmental behavior of coexisting NPs and surfactants in wastewater treatment processes. Full article
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Open AccessArticle
Biodegradability of Trimethylbenzene Isomers under Denitrifying and Sulfate-Reducing Conditions
Int. J. Environ. Res. Public Health 2019, 16(4), 615; https://doi.org/10.3390/ijerph16040615 - 20 Feb 2019
Abstract
Trimethylbenzene (TMB) isomers (1,2,3-TMB, 1,2,4-TMB, and 1,3,5-TMB) are often used as conservative tracers in anaerobic, contaminated aquifers for assessing BTEX (benzene, toluene, ethylbenzene, xylenes) biodegradation at field sites. However, uncertainties exist about the behavior of these compounds under anaerobic conditions. For this reason, [...] Read more.
Trimethylbenzene (TMB) isomers (1,2,3-TMB, 1,2,4-TMB, and 1,3,5-TMB) are often used as conservative tracers in anaerobic, contaminated aquifers for assessing BTEX (benzene, toluene, ethylbenzene, xylenes) biodegradation at field sites. However, uncertainties exist about the behavior of these compounds under anaerobic conditions. For this reason, the influence of various parameters (temperature, residence time) on the biodegradability of TMB isomers was investigated under denitrifying and sulfate-reducing conditions in microcosms and 1D-column experiments. Soil and groundwater contaminated with a cocktail of aromatic hydrocarbons including the TMB isomers, both collected from an industrial site in Berlin, Germany, were used for the laboratory investigations. A continuous and complete biodegradation of 1,3,5-TMB and 1,2,4-TMB under denitrifying conditions was observed independent of realized temperature (10–20 °C) and residence time. Biodegradation of 1,2,3-TMB started after longer lag-phases and was not continuous over the whole experimental period; a strong dependence on temperature and residence time was identified. The biodegradability of all TMB isomers under sulfate-reducing conditions was continuous and complete at higher temperatures (20 °C), whereas no degradation was observed for lower temperatures (10 °C). First-order biodegradation rate constants ranged from 0.05 to 0.21 d−1 for 1,3,5-TMB and 1,2,4-TMB and from 0.01 to 0.11 d−1 for 1,2,3-TMB. Full article
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Open AccessArticle
Control of Contaminant Transport Caused by Open-Air Heavy Metal Slag in Zhehai, Southwest China
Int. J. Environ. Res. Public Health 2019, 16(3), 443; https://doi.org/10.3390/ijerph16030443 - 02 Feb 2019
Abstract
Slag heaps are formed by mining waste materials, and the improper treatment of leachate from such heaps can threaten nearby aquifers. The Zhehai slag heap in Yunnan Province, China, contains 2.7 million tons of zinc and cadmium slag, and is considered a heavy [...] Read more.
Slag heaps are formed by mining waste materials, and the improper treatment of leachate from such heaps can threaten nearby aquifers. The Zhehai slag heap in Yunnan Province, China, contains 2.7 million tons of zinc and cadmium slag, and is considered a heavy metal source threatening the local groundwater safety, however, the severity of contamination remains unknown. In this study, numerical modeling was used to predict the groundwater flow and contaminant transport in this area based on field data. The results show that the atmospheric precipitation infiltration recharge at the top of the heap is 81.8 m3/d, accounting for 93.76% of total infiltration. The south and east sides of the area are the main outflow channels for contaminants, accounting for 93.25% of the total discharge around the heap. To reduce aquifer contamination, an in situ system involving a “controlling the source, ‘breaking’ the path, and intercepting the flow” (CSBPIF) strategy is established. The results indicate that the system performs well because it not only decreases the flow velocity but also reduces the concentrations of contaminants adsorbed by clay media. Moreover, the equivalent bottom liner thicknesses of the clay layers were calculated to improve the applicability of the CSBPIF system. Compared with ex situ disposal, this scheme provides an economic and effective solution and can be used to prevent and control groundwater pollution in China. Full article
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Open AccessArticle
Analyzing Mega City-Regions through Integrating Urbanization and Eco-Environment Systems: A Case Study of the Beijing-Tianjin-Hebei Region
Int. J. Environ. Res. Public Health 2019, 16(1), 114; https://doi.org/10.3390/ijerph16010114 - 03 Jan 2019
Cited by 2
Abstract
The high-speed economic growth of mega city-regions in China has been characterized by rapid urbanization accompanied by a series of environmental issues ranging from widespread soil contamination to groundwater depletion. This article begins with an analysis of the interaction between urbanization and the [...] Read more.
The high-speed economic growth of mega city-regions in China has been characterized by rapid urbanization accompanied by a series of environmental issues ranging from widespread soil contamination to groundwater depletion. This article begins with an analysis of the interaction between urbanization and the ecological system and reviews existing frameworks for analyzing urban and ecological systems. By taking the Beijing-Tianjin-Hebei region as an example, the article introduces a conceptual framework to analyze mega city-regions and forecast possible interactions between urbanization and eco-environment by applying simulation model. The proposed framework and its components can provide guidance to identify the impacts of urbanization and external forces such as globalization on eco-environment by integrating the internal and external factors, synthesize the complex components of mega city-regions in databases, understand and diagnose the casual relationship between urban policies and ecological consequences. Full article
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Open AccessArticle
Impact of Hydrous Manganese and Ferric Oxides on the Behavior of Aqueous Rare Earth Elements (REE): Evidence from a Modeling Approach and Implication for the Sink of REE
Int. J. Environ. Res. Public Health 2018, 15(12), 2837; https://doi.org/10.3390/ijerph15122837 - 12 Dec 2018
Cited by 1
Abstract
In this study, models were used for the first time to investigate the fate and transport of rare earth elements (REE) in the presence of hydrous manganese and ferric oxides in groundwaters from the coastal Bohai Bay (China). Results showed that REE sorption [...] Read more.
In this study, models were used for the first time to investigate the fate and transport of rare earth elements (REE) in the presence of hydrous manganese and ferric oxides in groundwaters from the coastal Bohai Bay (China). Results showed that REE sorption is strongly dependent on pH, as well as hydrous manganese and ferric oxide content. Higher proportions of REE were sorbed by hydrous manganese oxide as compared to hydrous ferric oxides, for example in the presence of neodymium. In this case, a mean 28% of this element was sorbed by hydrous manganese oxide, whereas an average 7% sorption was observed with hydrous ferric oxides. A contrasting REE sorption behavior was observed with hydrous manganese and ferric oxide for all investigated groundwaters. Specifically, REE bound to hydrous manganese oxides showed decreasing sorption patterns with increasing atomic number. The opposite trend was observed in the presence of hydrous ferric oxides. In addition, these results suggested that light REE (from La to Sm) rather than heavy REE (from Eu to Lu) are preferentially scavenged by hydrous manganese oxide. However, the heavy REE showed a greater affinity for hydrous ferric oxides compared to light REE. Therefore, both hydrous manganese and ferric oxide are important scavengers of REE. This study shows the implication of hydrous manganese and ferric oxide sorption for the sink of REE in groundwater. Full article
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Open AccessArticle
Remediating Potentially Toxic Metal and Organic Co-Contamination of Soil by Combining In Situ Solidification/Stabilization and Chemical Oxidation: Efficacy, Mechanism, and Evaluation
Int. J. Environ. Res. Public Health 2018, 15(11), 2595; https://doi.org/10.3390/ijerph15112595 - 20 Nov 2018
Cited by 1
Abstract
Most soil remediation studies investigated single contaminants or multiple contaminants of the same type. However, in field conditions, soils are often contaminated with potentially both toxic metals and organic pollutants, posing a serious technical challenge. Here, batch experiments were conducted to evaluate the [...] Read more.
Most soil remediation studies investigated single contaminants or multiple contaminants of the same type. However, in field conditions, soils are often contaminated with potentially both toxic metals and organic pollutants, posing a serious technical challenge. Here, batch experiments were conducted to evaluate the performance of combining in situ solidification/stabilization (ISS) and in situ chemical oxidation (ISCO) for the simultaneous removal of aniline (1000 mg/kg) and Cd (10 mg/kg). All four tested ISS amendments, especially quick lime and Portland cement, promoted in situ chemical oxidation with activated persulfate in contaminated soil. Combined ISS/ISCO remediation effectively removed aniline and reduced the bioavailable Cd content at optimal initial persulfate and ISS amendment concentrations of 1.08 mol/kg and 30 wt% with a seven-day curing time, and significantly reduced leaching. Persulfate inhibited the reduction of the bioavailable Cd content, and ISS amendment with persulfate did not synergistically remediate Cd in co-contaminated soil. Strong alkalinity and high temperature were the main mechanisms driving rapid pollutant removal and immobilization. The reaction of CaO with water released heat, and Ca(OH)2 formation increased the pH. The relative contributions of heat vs. alkaline activation, as well as the contaminant removal efficiency, increased with ISS amendment CaO content. Combined treatment altered the soil physicochemical properties, and significantly increased Ca and S contents. Activated persulfate-related reactions did not negatively impact unconfined compressive strength and hydraulic conductivity. This work improves the selection of persulfate activation methods for the treatment of soils co-contaminated with both potentially toxic metals and organic pollutants. Full article
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Open AccessArticle
Effects of Different Grazing Intensities on Soil C, N, and P in an Alpine Meadow on the Qinghai—Tibetan Plateau, China
Int. J. Environ. Res. Public Health 2018, 15(11), 2584; https://doi.org/10.3390/ijerph15112584 - 19 Nov 2018
Cited by 1
Abstract
Inappropriate grazing management is one of the most common causes of grassland degradation, and thus, an assessment of soil properties under different grazing intensities is critical for understanding its effects on ecosystem nutrient cycling and for formulating appropriate management strategies. However, the responses [...] Read more.
Inappropriate grazing management is one of the most common causes of grassland degradation, and thus, an assessment of soil properties under different grazing intensities is critical for understanding its effects on ecosystem nutrient cycling and for formulating appropriate management strategies. However, the responses of certain main elements, including soil carbon, nitrogen, and phosphorus, to grazing in alpine meadow ecosystems remain insufficiently clarified. Here, we measured carbon, nitrogen, and phosphorus contents in the topmost 30 cm of soil in an alpine meadow under three grazing intensities (light, moderate, and heavy) and found clear differences in soil physical and chemical properties among different grazing intensities and soil layers. As grazing intensity increased, soil water content, carbon and nitrogen contents and stocks, and carbon to phosphorus and nitrogen to phosphorus ratios decreased, whereas soil bulk density increased. However, soil phosphorus and carbon to nitrogen ratio remained stable. Our findings highlight the negative impacts of heavy grazing intensity, in terms of soil carbon and nitrogen loss and phosphorus mineralization. Moreover, we emphasize that further related studies are necessary to gain a more comprehensive understanding of the effects of grazing on grassland ecosystems, and thereby provide information for sustainable management practices and eco-compensation policies. Full article
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Open AccessArticle
Fly Ash Modified Coalmine Solid Wastes for Stabilization of Trace Metals in Mining Damaged Land Reclamation: A Case Study in Xuzhou Coalmine Area
Int. J. Environ. Res. Public Health 2018, 15(10), 2317; https://doi.org/10.3390/ijerph15102317 - 21 Oct 2018
Abstract
In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil [...] Read more.
In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil layer. However, it is very difficult to find adequate other backfill materials for substitution of gangues. In this paper, we present a novel method and case study to restrict the migration ability of trace metal elements in gangues by using another kind of coalmine solid waste—fly ashes from coal combustion. In this study, fly ashes were mixed with gangues in different mass proportions 1:0.2, 1:0.4, 1:0.6 and 1:0.8 as new designed backfill materials. Due to the help of fly ash, the occurrence states of studied trace metal elements were greatly changed, and their releasing and migration ability under hydrodynamic leaching effect were also significantly restricted. In this research seven trace metal elements in gangues Cu, Zn, Pb, Cd, Cr, Mn and Ni were studied by using soil column hydrodynamical leaching method and simulated precipitation for one year. The results show that under the driving of natural precipitation trace metal elements were generally transported deep inside the reconstructed land base, i.e., far away from soil layer and most of the trace metal elements were transformed into a bonded state, or combined in inert occurrence states, especially the residual state. With this method, the migration activities of tested trace metal elements were greatly restricted and the environmental potential risk could be significantly reduced. Full article
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Open AccessArticle
Spatial Assessment of Anthropogenic Impact on Trace Metal Accumulation in Farmland Soils from a Rapid Industrializing Region, East China
Int. J. Environ. Res. Public Health 2018, 15(9), 2052; https://doi.org/10.3390/ijerph15092052 - 19 Sep 2018
Cited by 1
Abstract
A better understanding of anthropogenic trace metal accumulation in farmland soils is crucial for local food safety and public health, especially for a rapidly industrializing region. In this study, soil samples at two depths were collected from a typical county in East China [...] Read more.
A better understanding of anthropogenic trace metal accumulation in farmland soils is crucial for local food safety and public health, especially for a rapidly industrializing region. In this study, soil samples at two depths were collected from a typical county in East China and analyzed for total concentrations of Fe, Al, Pb, Cd, Cu, Zn, Cr, and Ni. Results showed that trace metals like Pb, Cd, Cu, Zn, Cr, and Ni have accumulated in the regional farmlands, with average topsoil concentrations 1.62–1.77 times higher than their background concentrations in subsoil. However, they were still much lower than the limits of the Chinese Environmental Quality Standard for Soils. By the proper calculation of enrichment factor (EF), it was found that the accumulations of trace metals in the topsoil have been impacted by anthropogenic activities, which could contribute up to 40.83% of total metal concentration. Two principal components were extracted according to the results of principal component analysis (PCA) for EF values, which indicated two important anthropogenic trace metal sources. With the help of spatial distribution maps based on geographical information system (GIS), the anthropogenic sources of Pb, Cr, and Ni were determined to be mostly associated with atmospheric deposition from the central urban area. However, Cd, Cu, and Zn were further confirmed to originate from different agricultural sources. The anthropogenic Cu and Zn inputs were mostly related to pig manure application in the rural northern and southeastern areas, while extensive fertilizer application was identified as the major contributor to anthropogenic Cd accumulation in this region. Overall, the integrated application of EF, PCA, and GIS mapping is an effective approach to achieve the spatial assessment of anthropogenic impact on trace metal accumulation in regional soils. Full article
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Open AccessArticle
Treatment of Sewage Using a Constructed Soil Rapid Infiltration System Combined with Pre-Denitrification
Int. J. Environ. Res. Public Health 2018, 15(9), 2005; https://doi.org/10.3390/ijerph15092005 - 14 Sep 2018
Cited by 2
Abstract
The activated sludge process of the anaerobic/oxic (A/O) process has a good denitrification performance because it can make full use of the carbon source in the original sewage, and the denitrification can provide alkalinity for aerobic nitrification. The traditional constructed soil rapid infiltration [...] Read more.
The activated sludge process of the anaerobic/oxic (A/O) process has a good denitrification performance because it can make full use of the carbon source in the original sewage, and the denitrification can provide alkalinity for aerobic nitrification. The traditional constructed soil rapid infiltration (CSRI) system, on the other hand, has a poor nitrogen removal effect. Dividing the traditional CSRI system into two sections, one performs denitrification as an anoxic section, while the other performs nitrification as an aerobic section and is placed after the anoxic section. The nitrification liquid of the effluent from the aerobic section is mixed with the original wastewater and enters the anoxic section for denitrification. We expected that this would be improved by combining CSRI with a pre-denitrification step that would make full use of the carbon source in the original sewage. In a small-scale experimental model, the removal efficiencies of nitrogen, in the form of ammonium, nitrate, and total nitrogen (TN), as well as chemical oxygen demand (COD), were determined. The hydraulic load was varied, while the backflow reflux capacity was kept constant, to determine the effect on the pre-denitrification process. An average removal rate of 95.4% for NH4+-N and 96% for COD could be obtained when a hydraulic load of 80 cm3(cm2·d)−1 and a reflux ratio of 75% were applied. Under these conditions, the average removal rate of TN was 77.4%, which is much higher than what can be typically achieved with conventional CSRI systems. Full article
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Open AccessArticle
Catalytic Degradation of Diatrizoate by Persulfate Activation with Peanut Shell Biochar-Supported Nano Zero-Valent Iron in Aqueous Solution
Int. J. Environ. Res. Public Health 2018, 15(9), 1937; https://doi.org/10.3390/ijerph15091937 - 06 Sep 2018
Cited by 1
Abstract
An emerging pollutant, diatrizoate (DTZ) has been frequently detected in aqueous solution. Unique reticular peanut shell biochar (BC)-supported nano zero-valent iron (nZVI) composite (nZVI/BC) was successfully synthesized and used as a catalyst for activating persulfate (PS) to promote the removal of DTZ. The [...] Read more.
An emerging pollutant, diatrizoate (DTZ) has been frequently detected in aqueous solution. Unique reticular peanut shell biochar (BC)-supported nano zero-valent iron (nZVI) composite (nZVI/BC) was successfully synthesized and used as a catalyst for activating persulfate (PS) to promote the removal of DTZ. The structure and morphology of the nanocomposite materials were characterized by scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller measurements, and Fourier transform infrared spectroscopy. The degradation of DTZ (20 mg L−1) was achieved by activating PS with the nanocomposite material. The removal of DTZ reached nearly 100% using 25 mM PS and 0.45 g L−1 nZVI/2BC (mass ratio of nZVI and BC at 1:2) nanocomposite material at pH 3.0 and 25 °C. Influencing factors, such as dosages of nZVI/2BC and PS, temperature, and pH were also investigated. The mechanisms of PS activation with nZVI/2BC were discussed, including BC property, electron transfer, and the identification of free radicals in the reaction. The findings demonstrated that nZVI/BC-PS (peanut shell BC-supported nZVI activating PS) is a promising material for the treatment of refractory organic pollutants. Full article
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Review

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Open AccessReview
Vegetation Response to Groundwater Variation in Arid Environments: Visualization of Research Evolution, Synthesis of Response Types, and Estimation of Groundwater Threshold
Int. J. Environ. Res. Public Health 2019, 16(10), 1849; https://doi.org/10.3390/ijerph16101849 - 24 May 2019
Cited by 1
Abstract
Groundwater depth is an important environmental factor affecting vegetation growth and landscape dynamics in arid environments. This study applied a science mapping approach to visualize the development of groundwater-vegetation-related research, synthesized the vegetation response to changes in groundwater depth, and analyzed the change [...] Read more.
Groundwater depth is an important environmental factor affecting vegetation growth and landscape dynamics in arid environments. This study applied a science mapping approach to visualize the development of groundwater-vegetation-related research, synthesized the vegetation response to changes in groundwater depth, and analyzed the change rate of the response curve to identify the groundwater threshold that is essential to conserve the groundwater-dependent terrestrial ecosystems. These ecosystems emerged as a research hotspot due to climate change, groundwater overexploitation, and the recognition of these ecosystems’ importance for sustainable development. There are two main types of response functions of vegetation to changes in groundwater depth—monotone and bell-shaped functions—among which the monotone function includes linear, curvilinear, and stepwise response. The shape of a response curve is mainly determined by the combined effects of oxygen stress, salinization, and water stress; oxygen stress and salinization dominate in shallow groundwater depth, while water stress dominates in deep groundwater depth. On a non-linear vegetation metric—groundwater depth response curve, the change rate analysis method is effective to identify the breakpoint that can be taken as a candidate threshold of groundwater depth. The results will add insight into the intellectual structure of the groundwater-vegetation interactions and provide practical reference for groundwater resource management, ecological conservation, and sustainable development in arid environments. Full article
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