Accumulation and transport of ammonium in aquitards in the Pearl River Delta (China) in the last 10,000  years: conceptual and numerical models

Wang, Xusheng; Jiao, Jiu Jimmy; Wang, Ya; Cherry, John A.; Kuang, Xingxing; Liu, Kun; Lee, Chunming; Gong, Zizheng

doi:10.1007/s10040-013-0976-1

Cited by 29 publications

(25 citation statements)

References 27 publications

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“…The advection was assumed to follow Darcy's law, and there is no threshold hydraulic gradient (Neuzil, ). Similar to previous studies, the compaction‐driven flow was ignored (Beekman et al ., ; Tokunaga et al ., ; Wang et al ., 2013a). In the simulations, the aquitard and the aquifer were assumed to be individually homogeneous.…”

Section: Numerical Simulationmentioning

confidence: 99%

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Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

2015

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Abstract:Sedimentation may have a significant effect on the transport of solutes and environmental isotopes in sediment. The depth profiles of the Cl À , δ 2 H and δ 18 O in a borehole in the aquifer-aquitard system in the Pearl River Delta (PRD), China, were obtained by centrifuging the core sediment samples. A one-dimensional model based on the sedimentation and sea level changes of the PRD during the Holocene was built to investigate numerically the transport mechanisms of Cl À , δ 2 H and δ 18O. The sedimentation process was modelled as a moving boundary problem with the moving rate equal to the sedimentation rate. The model was calibrated and the parameters were obtained by comparing simulated and measured data. Very good agreement between all the three observed profiles and the simulated ones demonstrates the reliability of the model and the parameters. Simulation results show that the shapes of the curves are controlled by the combination of sedimentation and upper boundary conditions. Diffusion solely is adequate to reconstruct the observed profiles, which indicates that diffusion is the dominant vertical transport mechanism. The effective diffusion coefficients of the aquitard and the aquifer equal to 5.0 × 10 À11 and 2.0 × 10 À10 m 2 /s, respectively. The results of this study will help in understanding the transport mechanisms of solutes and environmental tracers in deltas with geology and hydrogeology similar to the PRD.

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Section: Numerical Simulationmentioning

confidence: 99%

“…In the Pearl River Delta (PRD), Wang et al . (2013a) simulated the salinity profiles in two boreholes using a one‐dimensional numerical model with MODFLOW‐96 (McDonald and Harbaugh, ; Harbaugh and McDonald, ) and MT3D (Zheng, ).…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

2015

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“…Because of the humid-warm climatic conditions of the PRD, the soil profile is relatively deficient in soluble salts, alkali metals, and alkali-earth metals but is rich in Fe and Al oxides . The delta has been influenced by several transgressive events since the early Pleistocene (Wang et al, 2013a). There are many terraces in the PRD, and the highest is the fifth-stage terrace.…”

Section: Site Descriptionsmentioning

confidence: 99%

“…In some studies, stable isotopes used as tracers for the surface water recharge of groundwater, and hydrogeochemical diagrams such as Piper third-line diagrams, have been used (Wang and Jiao, 2012;Wang et al, 2013b;Yuan et al, 2013). The quality of groundwater can be influenced by the dry fallout of atmospheric particulate matter, by the chemical weathering of rocks and soils (Wang and Jiao, 2012;Wang et al, 2013a), by the mixing of freshwater and seawater (Wang et al, 2013b) and by anthropogenic sources (Huang et al, 2011;Liu et al, 2011;. Studies have been conducted on trace metal contamination in the PRD, but these studies have focused on the surface sediment and river water of the Pearl River Estuary or on only As in the groundwater (Huang et al, 2011;Liu et al, 2011;.…”

Section: Introductionmentioning

confidence: 99%

Assessment of major ions and heavy metals in groundwater: a case study from Guangzhou and Zhuhai of the Pearl River Delta, China

Tang

Chen

et al. 2015

Front. Earth Sci.

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Anthropogenic activities in the Pearl River Delta (PRD) have caused a deterioration of groundwater quality over the past twenty years as a result of rapid urbanization and industrial development. In this study, the hydrochemical characteristics, quality, and sources of heavy metals in the groundwater of the PRD were investigated. Twenty-five groundwater samples were collected and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), δ 18 O, δ 2 H, major ions, and heavy metals. The groundwater was slightly acidic and presented TDS values that ranged from 35.5 to 8,779.3 mg$L -1 . The concentrations of the major ions followed the order Cl -> HCO -Ca-Mg-HCO 3 and Na-K-HCO 3 were the predominant types of facies, and the chemical composition of the groundwater was primarily controlled by chemical weathering of the basement rocks, by mixing of freshwater and seawater and by anthropogenic activities. The heavy metal pollution index (HPI) indicated that 64% of the samples were in the low category, 16% were in the medium category and 20% were in the high category, providing further evidence that this groundwater is unsuitable for drinking. Lead, arsenic, and manganese were mainly sourced from landfill leachate; cadmium from landfill leachate and agricultural wastes; mercury from the discharge of leachate associated with mining activities and agricultural wastes; and chromium primarily from industrial wastes. According to the irrigation water quality indicators, the groundwater in the PRD can be used for irrigation in most farmland without strong negative impacts. However, approximately 9 million people in the Guangdong Province are at risk due to the consumption of untreated water. Therefore, we suggest that treating the groundwater to achieve safer levels is necessary.

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“…The effective porosity was supposed to be equal to the porosity, namely, = (total porosity) [5,42]. More, compaction-driven flow was also ignored according to the previous researches on aquitard-aquifer system [14,15,53]. Beyond that, the aquifer and aquitard were assumed to be individually homogeneous.…”

Section: Conceptual Transport Modelmentioning

confidence: 99%

Cl⁻ as a Chemical Fingerprint of Solute Transport in the Aquitard-Aquifer System of the North Jiangsu Coastal Plain, China

Ge¹,

Liang²,

Jin³

et al. 2017

Geofluids

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Detailed vertical profiles of Cl− in porewaters through the aquitard-aquifer system were used to yield solute transport mechanism and build a conceptual model regarding evolution processes and transport time of natural tracer migration in North Jiangsu coastal plain, China. One-dimensional vertical simulated models of Cl − profiles illustrate that diffusion appeared to be the dominant solute transport mechanism in the aquitard-aquifer system. A downward groundwater flow did not improve the fitness between simulated and measured values. Several simulated models were constructed and suggested that the evolution of the Cl − profiles is mainly ascribed to the introduction of seawater and freshwater of transgression-regression to the first confined aquifer and the upper boundary. Groundwater in the first confined aquifer recharged by the Late Pleistocene glacial meltwater (25-15 ka BP) was supported in response to the low Cl − concentrations. The shallow groundwater in the first confined aquifer and porewater with high salt were attributable to the Holocene seawater intrusion. These timeframes were also consistent favorably with the results of previous studies into the palaeohydrology of the study area.

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Accumulation and transport of ammonium in aquitards in the Pearl River Delta (China) in the last 10,000 years: conceptual and numerical models

Cited by 29 publications

References 27 publications

Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

Assessment of major ions and heavy metals in groundwater: a case study from Guangzhou and Zhuhai of the Pearl River Delta, China

Cl⁻ as a Chemical Fingerprint of Solute Transport in the Aquitard-Aquifer System of the North Jiangsu Coastal Plain, China

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Accumulation and transport of ammonium in aquitards in the Pearl River Delta (China) in the last 10,000 years: conceptual and numerical models

Cited by 29 publications

References 27 publications

Numerical studies of vertical Cl−, δ2H and δ18O profiles in the aquifer-aquitard system in the Pearl River Delta, China

Numerical studies of vertical Cl−, δ2H and δ18O profiles in the aquifer-aquitard system in the Pearl River Delta, China

Assessment of major ions and heavy metals in groundwater: a case study from Guangzhou and Zhuhai of the Pearl River Delta, China

Cl− as a Chemical Fingerprint of Solute Transport in the Aquitard-Aquifer System of the North Jiangsu Coastal Plain, China

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Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

Numerical studies of vertical Cl⁻, δ²H and δ¹⁸O profiles in the aquifer-aquitard system in the Pearl River Delta, China

Cl⁻ as a Chemical Fingerprint of Solute Transport in the Aquitard-Aquifer System of the North Jiangsu Coastal Plain, China