scholarly journals Analysis of Hydrogeochemical Characteristics and Origins of Chromium Contamination in Groundwater at a Site in Xinxiang City, Henan Province

2021 ◽  
Vol 11 (24) ◽  
pp. 11683
Author(s):  
Wenfang Chen ◽  
Yaobin Zhang ◽  
Weiwei Shi ◽  
Yali Cui ◽  
Qiulan Zhang ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Groundwater Remediation ◽  
Saturation Index ◽  
Shallow Groundwater ◽  
Distribution Patterns ◽  
Scientific Basis ◽  
Henan Province ◽  
Contaminated Site ◽  
Control Mechanisms ◽  
Chromium Contamination

Hexavalent chromium contamination in groundwater has become a very serious and challenging problem. Identification of the groundwater chemical characteristics of the sites and their control mechanisms for remediation of pollutants is a significant challenge. In this study, a contaminated site in Xinxiang City, Henan Province, was investigated and 92 groundwater samples were collected from the site. Furthermore, the hydrogeochemical characteristics and the distribution patterns of components in the groundwater were analyzed by a combination of multivariate statistical analysis, Piper diagram, Gibbs diagram, ions ratio and hydrogeochemical simulation. The results showed that the HCO3-Cl-Mg-Ca type, SO4-HCO3-Na type, and HCO3-Mg-Ca-Na type characterize the hydrogeochemical composition of shallow groundwater and HCO3-Cl-Mg-Ca type, HCO3-Na-Mg type, and HCO3-SO4-Mg-Na-Ca type characterize the hydrogeochemical composition of deep groundwater. Ion ratios and saturation index indicated that the groundwater hydrogeochemical characteristics of the study area are mainly controlled by water–rock action and evaporative crystallization. The dissolution of halite, gypsum and anhydrite, the precipitation of aragonite, calcite and dolomite, and the precipitation of trivalent chromium minerals other than CrCl3 and the dissolution of hexavalent chromium minerals occurred in groundwater at the site. The minimum value of pH in groundwater at the site is 7.55 and the maximum value is 9.26. The influence of pH on the fugacity state of minerals was further investigated. It was concluded that the saturation index of dolomite, calcite, aragonite and MgCr2O4 increases with the increase of pH, indicating that these minerals are more prone to precipitation, and the saturation index of Na2Cr2O7, K2Cr2O7 and CrCl3 decreases with the increase of pH, implying that Na2Cr2O7, K2Cr2O7 and CrCl3 are more prone to dissolution. The saturation index of the remaining minerals is less affected by pH changes. The study can provide a scientific basis for groundwater remediation.

Study on leaching kinetics of hexavalent chromium from aged calcium-free chromium slag

2021 ◽  
pp. 1-13
Author(s):  
Quan Qi ◽  
Liang Li ◽  
Liangyu Wei ◽  
Baoming Hu ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Resource Utilization ◽  
Scientific Basis ◽  
Diffusion Reaction ◽  
Leaching Kinetics ◽  
Leaching Rate ◽  
Chromium Slag ◽  
Leaching Solution ◽  
Main Components ◽  
Kinetics Of

To provide a scientific basis for the resource utilization of chromium slag, this article studies the release law of hexavalent chromium in the aged calcium-free chromium slag. XRD (X-ray diffractometer) and MLA (Mineral Liberation Analyzer) were used to analyze the composition of the chromium slag; using sulfuric acid-nitric acid as the leaching solution, the release law of hexavalent chromium in chromium slag and the leaching kinetics were studied. The results show that main components of the chromium slag are magnesioferrite, chromite, hematite, hydrargillite, and spinel; chromium is mainly present in chromite and magnesioferrite; the leaching rate of hexavalent chromium increases with the increase of temperature or the decrease of pH. The analysis of leaching kinetics shows the leaching rate is controlled by the internal diffusion reaction, and the apparent activation energy is 11.93 kJ·mol–1. The chromium slag is aged in high temperature seasons, which is conducive to the precipitation of hexavalent chromium in the chromium slag, can increase the yield of chromate in the roasting kiln, and is conducive to resource utilization; chromium slag should be stored in order to prevent acid rain erosion which leads to environmental pollution risk (e.g. drinking water).

Remediation of MTBE-contaminated groundwater by integrated circulation wells and advanced oxidation technologies

2017 ◽  
Vol 18 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Bassam Tawabini ◽  
Mohammed Makkawi
Keyword(s):  
Groundwater Remediation ◽  
Treatment Time ◽  
Shallow Groundwater ◽  
Advanced Oxidation ◽  
Shallow Aquifer ◽  
Contaminated Groundwater ◽  
Butyl Ether ◽  
Tertiary Butyl ◽  
Industrial Facilities ◽  
Environmental Threats

Abstract The proximity of shallow groundwater systems to sources of contamination usually exposes them to severe environmental threats. Hazardous pollutants that leak from gas stations, landfills, and industrial facilities may eventually reach the underneath shallow groundwater aquifers, posing risks to human health and the environment. Cleaning contaminated groundwater sources has always been a challenge to the local authorities. This is even more challenging when dealing with difficult pollutants such as methyl tertiary butyl ether (MTBE) due its high solubility in water, poor biodegradability, and poor adsorption onto solids. This study aims to assess the efficiency of a pilot groundwater remediation system to treat a shallow aquifer contaminated with MTBE. The in-house designed and fabricated pilot system combines the technology of circulation wells and UV-based advanced oxidation technology for the breakdown and removal of MTBE from water. An ultraviolet/hydrogen peroxide (UV/H2O2) process was used in this study to remove MTBE from water. The concentration of MTBE was reduced from approximately 1,400 μg/L to as low as 34 μg/L within 30 minutes, with a treatment efficiency of about 98%. The study also assesses the effects of the UV intensity and the treatment time needed to remove the target pollutant.

scholarly journals Hydrogeochemistry and Quality Assessment of Shallow Groundwater in the Southern Part of the Yellow River Alluvial Plain (Zhongwei Section), Northwest China

2014 ◽  
Vol 18 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Peiyue Li ◽  
Jianhua Wu ◽  
Hui Qian
Keyword(s):  
Water Quality ◽  
Yellow River ◽  
Saturation Index ◽  
Shallow Groundwater ◽  
Northwest China ◽  
Alluvial Plain ◽  
Total Hardness ◽  
The Yellow River ◽  
Human Consumption ◽  
Mineralized Water

<p class="MsoNormal" style="line-height: 200%;">Statistical analyses, a Piper diagram, the saturation index and the correlations of chemical parameters were used to reveal the hydrogeochemistry and hydrogeochemical evolution of shallow groundwater in the southern part of the Zhongwei section of the Yellow River alluvial plain. The water quality for agricultural and domestic uses was also assessed in the study. The results suggest that the shallow groundwater in the study area is fresh to moderately mineralized water. Higher Ca<sup>2+</sup> and HCO<sub>3</sub><sup>-</sup> are observed in the less mineralized water, whereas Na<sup>+</sup> and SO<sub>4</sub><sup>2-</sup> are common ions in the highly mineralized water. The major hydrochemical facies for groundwater with total dissolved solids (TDS) &lt;1 g/L are HCO<sub>3</sub>-Ca·Mg and HCO<sub>3</sub>-Ca·Na·Mg, and for groundwater with TDS &gt; 1 g/L, SO<sub>4</sub>·Cl-Na and SO<sub>4</sub>·Cl-Na·Mg·Ca are the predominant hydrochemical types. The main reactions in the groundwater system are the dissolution/precipitation of gypsum, fluorite, halite, calcite and dolomite. Cation exchange is also important in controlling the groundwater chemistry. The water samples assessed in the paper are of acceptable quality for agricultural use, but most of them are not fit for direct human consumption (drinking). TDS, total hardness (TH), Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup> are the main indices that result in the poor drinking water quality.</p><p class="MsoNormal" style="line-height: 200%;"> </p><p class="MsoNormal" style="line-height: 200%;"><strong>Resumen</strong></p><p>Análisis estadísticos, un diagrama de Piper, el índice de saturación y la correlación de los parámetros químicos fueron utilizados para revelar la hidrogeoquímica y la evolución hidrogeoquímica de las aguas subterráneas poco profundas en la parte sur de la sección Zhongwei en la planicie aluvial del río Amarillo. La calidad del agua para el uso doméstico y agrícola también fue evaluada en este estudio. Los resultados sugieren que las aguas subterráneas poco profundas en el área de estudio son entre frescas y moderadamente mineralizadas. Un índice mayor de Ca2+ y HCO3- se observó en las aguas menos mineralizadas, mientras que Na+ y SO42- son iones comunes en las aguas altamente mineralizadas. Los perfiles hidroquímicos predominantes para las aguas subterráneas con Total de Sólidos Disueltos (TDS) &lt;1 g/L son HCO3-Ca·Mg y HCO3-Ca·Na·Mg, y para las aguas subterráneas con TDS &gt;1 g/L, SO4·Cl-Na y SO4·Cl-Na·Mg·Ca. Las mayores reacciones en el sistema de aguas subterráneas son la disolución/ precipitación de yeso, fluorita, halita, calcita y dolomita. El intercambio de cationes también es importante en el control de la química de las aguas subterráneas. Las muestras de agua evaluadas en este manuscrito son de calidad aceptable para el uso agrícola, pero la mayoría no son aptas para el consumo humano. El índice TDS, la dureza total del agua (TH), Cl- y SO42- son las razones principales que influyen en la baja calidad de esta agua.</p>

scholarly journals Environmental Isotope of Radon-222 for Ciliwung River and Shallow Deep Water Interaction Study

2020 ◽  
Vol 21 (2) ◽  
pp. 139
Author(s):  
Evarista Ristin Pujiindiyati ◽  
Bungkus Pratikno
Keyword(s):  
River Water ◽  
Residence Time ◽  
Shallow Groundwater ◽  
Infiltration Rate ◽  
Scientific Basis ◽  
Dry Season ◽  
River Bank ◽  
222Rn Concentration ◽  
Significant Difference ◽  
Groundwater Infiltration

Aquifer in river bank area is mostly susceptive toward pollution occurring in river. One of parameters to determine the interaction process between groundwater and river is a natural isotope of 222Rn. The significant difference of radon concentration in groundwater and river water can be utilized as a scientific basis for investigating groundwater infiltration in river bank. Those studied parameters are residence time and infiltration rate. The research using 222Rn had been conducted in shallow groundwater of Ciliwung river bank - South Jakarta during rainy and dry season. The range of 222Rn concentration in shallow groundwater monitored in dry season was between 666 - 2590 Bq/m3 which was higher than that of rainy season ranging at 440 to 1546 Bq/m3. Otherwise, concentration of 222Rn in river water could not be detected (its 222Rn concentration = 0 Bq/m3) due to its much lower concentration either rainy or dry season. During dry season monitoring, equilibration between groundwater and river water was reached at the distance approximately 98 - 140 m away from river side. Estimating residence time based on 222Rn concentration at nearest site from the river and at equlibration area was 4.2 days such that the infiltration rate from river water into aquifer might be 7.8 m/day.Keywords: 222Rn, groundwater, residence time, infiltration rate.

scholarly journals Anthropogenic Effects on Hydrogeochemical Characterization of the Shallow Groundwater in an Arid Irrigated Plain in Northwestern China

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2247 ◽  
Author(s):  
Wang ◽  
Mei ◽  
Yu ◽  
Li ◽  
Meng ◽  
...  
Keyword(s):  
Groundwater Quality ◽  
Saturation Index ◽  
Shallow Groundwater ◽  
Total Hardness ◽  
Agricultural Activity ◽  
Residential Areas ◽  
Weathering Processes ◽  
Natural Processes ◽  
Geostatistical Techniques ◽  
Hydrogeochemical Characterization

Many irrigated plains in arid and semi-arid regions have groundwater quality issues due to both intensive human activity and natural processes. Comprehensive studies are urgently needed to explore hydrogeochemical evolutions, investigate possible pollution sources, and understand the controls on groundwater compositions in such regions. Here, we combine geostatistical techniques and hydrogeochemical assessments to characterize groundwater quality over time in the Yinchuan Plain (a typical irrigated plain in China), using 12 physicochemical variables derived from sampling in 600 and 602 wells in 2004 and 2014, respectively. Our results show that groundwater-rock interactions and evaporation are the key natural factors controlling groundwater compositions. Hydrogeochemical water types in both 2004 and 2014 were Ca-HCO3, Na-Cl, and mixed Ca·Mg-Cl. Along with the hydrogeochemical compositions, we used ionic ratios and the saturation index to delineate mineral solution reactions and weathering processes. Dissolution of gypsum, halite, fluorite, and mirabilite, along with silicate weathering and cation exchange, were identified in the study area. Our results indicated rising ion concentrations in groundwater, which could be the result of anthropogenic influences. Increasing total hardness and nitrates over the study period were most likely caused by agricultural activity and the discharge of waste water from human residential areas.

Groundwater Remediation of Hexavalent Chromium Along the Columbia River at the Hanford Site in Washington State, USA

2011 ◽  
Author(s):  
Dyan L. Foss ◽  
Briant L. Charboneau
Keyword(s):  
Hexavalent Chromium ◽  
Groundwater Remediation ◽  
Columbia River ◽  
Washington State ◽  
Department Of Energy ◽  
Hanford Site ◽  
Pump And Treat ◽  
Environmental Setting ◽  
Calcium Polysulfide

The U.S. Department of Energy Hanford Site, formerly used for nuclear weapons production, encompasses 1500 square kilometers in southeast Washington State along the Columbia River. A principle threat to the river are the groundwater plumes of hexavalent chromium (Cr(VI)), which affect approximately 9.8 square kilometers, and 4.1 kilometers of shoreline. Cleanup goals are to stop Cr(VI) from entering the river by the end of 2012 and remediate the groundwater plumes to the drinking water standards by the end of 2020. Five groundwater pump-and-treat systems are currently in operation for the remediation of Cr(VI). Since the 1990s, over 13.6 billion L of groundwater have been treated; over 1,435 kg of Cr(VI) have been removed. This paper describes the unique aspects of the site, its environmental setting, hydrogeology, groundwater-river interface, riverine hydraulic effects, remediation activities completed to date, a summary of the current and proposed pump-and-treat operations, the in situ redox manipulation barrier, and the effectiveness of passive barriers, resins, and treatability testing results of calcium polysulfide, biostimulation, and electrocoagulation, currently under evaluation.

Characteristics of Hydrogeochemistry and Groundwater Quality in a Riverbank Filtration Site, Northeastern China

2020 ◽  
Author(s):  
Yanguo Teng ◽  
Yuanzheng Zhai ◽  
Haiyang Chen ◽  
Ruihui Chen
Keyword(s):  
Spatial Distribution ◽  
Groundwater Quality ◽  
Land Surface ◽  
Evaluation Method ◽  
Major Ions ◽  
Comprehensive Evaluation ◽  
Shallow Groundwater ◽  
Distribution Patterns ◽  
Total Hardness ◽  
Spatial Distribution Patterns

&lt;p&gt;Studies on hydrogeochemical characteristics and an assessment of the groundwater quality for drinking purposes were conducted in and around the riverside source field of Wuchang, Northeast China. Twenty-seven and twenty-three shallow groundwater samples were collected for measuring on-site parameters and major components in the years 2000 and 2014, respectively. In 2014, the average concentrations of major ions of shallow groundwater were found to be in the following order: Ca&lt;sup&gt;2+&lt;/sup&gt;&gt; Na&lt;sup&gt;+&lt;/sup&gt;&gt; Mg&lt;sup&gt;2+&lt;/sup&gt;&gt; K&lt;sup&gt;+&lt;/sup&gt; for cations and HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;&gt; SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;&gt; Cl&lt;sup&gt;-&lt;/sup&gt;&gt; NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; for anions. The spatial distribution patterns of K&lt;sup&gt;+&lt;/sup&gt; and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; had no obvious regularity, whereas Cl&lt;sup&gt;-&lt;/sup&gt; and Na&lt;sup&gt;+ &lt;/sup&gt;showed similar spatial distribution patterns. Ca-HCO&lt;sub&gt;3&lt;/sub&gt; and mixed type water were the dominant hydrochemical types. The analysis of the SI values for minerals and the Gibbs plot illustrated that the concentrations of major components were mainly controlled by rock weathering, such as the dissolution of calcite, dolomite, halite, gypsum and aragonite, followed by ion exchange. Indicators, such as Total hardness (TH), Total Dissolved Solids (TDS), Cl&lt;sup&gt;-&lt;/sup&gt;, SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2- &lt;/sup&gt;and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;, were selected to assess the groundwater quality using a comprehensive evaluation method of dividing the groundwater quality into five classes: excellent, good, fair, poor and very poor water. The results showed that 7.4% and 34.8% of the total groundwater sample in 2000 and 2014, respectively, were unsuitable for drinking use, indicating that the shallow groundwater quality has gradually worsened in the past few decades. The concentration of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;- &lt;/sup&gt;was a major factor that influenced the observed groundwater quality changes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgments &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;This study was supported by the NSFC (No.41877355), Beijing Advanced Innovation Program for Land Surface Science, and the&amp;#160;111 Project of China (B18006).&lt;/p&gt;

scholarly journals HUMAN LEUKEMIC CELLS CYTOCHEMICAL STUDIES ON ACIDIC NUCLEAR PROTEINS

1974 ◽  
Vol 22 (1) ◽  
pp. 40-45 ◽  
Author(s):  
L. S. DESAI ◽  
G. E. FOLEY
Keyword(s):  
Toluidine Blue ◽  
Diagnostic Category ◽  
Distribution Patterns ◽  
Dry Mass ◽  
Nuclear Proteins ◽  
Leukemic Cells ◽  
Control Mechanisms ◽  
Acidic Proteins ◽  
Human Leukemic Cells ◽  
Individual Human

Utilizing staining with alkaline fast green (pH 8.1) and toluidine blue O (pH 9.0) stains, the nuclear basic and acidic protein content of individual human lymphocytic cells has been quantitated cytochemically with high resolution, rapid scanning instruments. There were distinct differences in the distribution patterns of the acidic and basic proteins in these human lymphocytic cells. Nucleoli were densely stained by toluidine blue O, confirming the presence of acidic proteins. The acidic nuclear proteins:DNA and basic nuclear proteins:DNA ratios are consistent and quantitatively similar, irrespective of the diagnostic category from which the cells derived and there was a definite correlation between nuclear proteins and DNA content. However, the acidic nuclear proteins represented a larger proportion of the total dry mass of the cell than did the basic nuclear proteins, an observation which may prove to be of interest with respect to control mechanisms.

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