The Experts below are selected from a list of 96 Experts worldwide ranked by ideXlab platform
Chi Sun Poon - One of the best experts on this subject based on the ideXlab platform.
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three dimensional spatial variability of arsenic containing soil from Geogenic Source in hong kong implications on sampling strategies
Science of The Total Environment, 2018Co-Authors: Y F Leung, Jiangshan Li, Daniel C W Tsang, Lei Wang, Chi Yan Lo, Man Tat Leung, Chi Sun PoonAbstract:Abstract Soil contamination by trace elements such as arsenic (As) can pose considerable threats to human health, and need to be carefully identified through site investigation before the soil remediation and development works. However, due to the high costs of soil sampling and testing, decisions on risk management or mitigation strategies are often based on limited data at the site, with substantial uncertainty in the spatial distributions of potentially toxic elements. This study incorporates the restricted maximum likelihood method with three-dimensional spatial autocovariance structure, to investigate the spatial variability features of As-containing soils of Geogenic origin. A recent case study in Hong Kong is presented, where >550 samples were retrieved and tested for distributions of As concentrations. The proposed approach is applied to characterize their spatial correlation patterns, to predict the As concentrations at unsampled locations, and to quantify the uncertainty of such estimates. The validity of the approach is illustrated by utilizing the multi-stage site investigation data, through which the advantages of the approach over traditional geostatistical methods are revealed and discussed. The new approach also quantifies the effectiveness of soil sampling on reduction of uncertainty levels across the site. This can become a useful indicator for risk management or mitigation strategies, as it is often necessary to balance between the available reSources for soil sampling at the site and the needs for proper characterization of contaminant distributions.
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arsenic containing soil from Geogenic Source in hong kong leaching characteristics and stabilization solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
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Arsenic-containing soil from Geogenic Source in Hong Kong: Leaching characteristics and stabilization/solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
Jiangshan Li - One of the best experts on this subject based on the ideXlab platform.
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three dimensional spatial variability of arsenic containing soil from Geogenic Source in hong kong implications on sampling strategies
Science of The Total Environment, 2018Co-Authors: Y F Leung, Jiangshan Li, Daniel C W Tsang, Lei Wang, Chi Yan Lo, Man Tat Leung, Chi Sun PoonAbstract:Abstract Soil contamination by trace elements such as arsenic (As) can pose considerable threats to human health, and need to be carefully identified through site investigation before the soil remediation and development works. However, due to the high costs of soil sampling and testing, decisions on risk management or mitigation strategies are often based on limited data at the site, with substantial uncertainty in the spatial distributions of potentially toxic elements. This study incorporates the restricted maximum likelihood method with three-dimensional spatial autocovariance structure, to investigate the spatial variability features of As-containing soils of Geogenic origin. A recent case study in Hong Kong is presented, where >550 samples were retrieved and tested for distributions of As concentrations. The proposed approach is applied to characterize their spatial correlation patterns, to predict the As concentrations at unsampled locations, and to quantify the uncertainty of such estimates. The validity of the approach is illustrated by utilizing the multi-stage site investigation data, through which the advantages of the approach over traditional geostatistical methods are revealed and discussed. The new approach also quantifies the effectiveness of soil sampling on reduction of uncertainty levels across the site. This can become a useful indicator for risk management or mitigation strategies, as it is often necessary to balance between the available reSources for soil sampling at the site and the needs for proper characterization of contaminant distributions.
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arsenic containing soil from Geogenic Source in hong kong leaching characteristics and stabilization solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
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Arsenic-containing soil from Geogenic Source in Hong Kong: Leaching characteristics and stabilization/solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
Scott Fendorf - One of the best experts on this subject based on the ideXlab platform.
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arsenic containing soil from Geogenic Source in hong kong leaching characteristics and stabilization solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
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Arsenic-containing soil from Geogenic Source in Hong Kong: Leaching characteristics and stabilization/solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
Daniel C W Tsang - One of the best experts on this subject based on the ideXlab platform.
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three dimensional spatial variability of arsenic containing soil from Geogenic Source in hong kong implications on sampling strategies
Science of The Total Environment, 2018Co-Authors: Y F Leung, Jiangshan Li, Daniel C W Tsang, Lei Wang, Chi Yan Lo, Man Tat Leung, Chi Sun PoonAbstract:Abstract Soil contamination by trace elements such as arsenic (As) can pose considerable threats to human health, and need to be carefully identified through site investigation before the soil remediation and development works. However, due to the high costs of soil sampling and testing, decisions on risk management or mitigation strategies are often based on limited data at the site, with substantial uncertainty in the spatial distributions of potentially toxic elements. This study incorporates the restricted maximum likelihood method with three-dimensional spatial autocovariance structure, to investigate the spatial variability features of As-containing soils of Geogenic origin. A recent case study in Hong Kong is presented, where >550 samples were retrieved and tested for distributions of As concentrations. The proposed approach is applied to characterize their spatial correlation patterns, to predict the As concentrations at unsampled locations, and to quantify the uncertainty of such estimates. The validity of the approach is illustrated by utilizing the multi-stage site investigation data, through which the advantages of the approach over traditional geostatistical methods are revealed and discussed. The new approach also quantifies the effectiveness of soil sampling on reduction of uncertainty levels across the site. This can become a useful indicator for risk management or mitigation strategies, as it is often necessary to balance between the available reSources for soil sampling at the site and the needs for proper characterization of contaminant distributions.
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arsenic containing soil from Geogenic Source in hong kong leaching characteristics and stabilization solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
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Arsenic-containing soil from Geogenic Source in Hong Kong: Leaching characteristics and stabilization/solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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three dimensional spatial variability of arsenic containing soil from Geogenic Source in hong kong implications on sampling strategies
Science of The Total Environment, 2018Co-Authors: Y F Leung, Jiangshan Li, Daniel C W Tsang, Lei Wang, Chi Yan Lo, Man Tat Leung, Chi Sun PoonAbstract:Abstract Soil contamination by trace elements such as arsenic (As) can pose considerable threats to human health, and need to be carefully identified through site investigation before the soil remediation and development works. However, due to the high costs of soil sampling and testing, decisions on risk management or mitigation strategies are often based on limited data at the site, with substantial uncertainty in the spatial distributions of potentially toxic elements. This study incorporates the restricted maximum likelihood method with three-dimensional spatial autocovariance structure, to investigate the spatial variability features of As-containing soils of Geogenic origin. A recent case study in Hong Kong is presented, where >550 samples were retrieved and tested for distributions of As concentrations. The proposed approach is applied to characterize their spatial correlation patterns, to predict the As concentrations at unsampled locations, and to quantify the uncertainty of such estimates. The validity of the approach is illustrated by utilizing the multi-stage site investigation data, through which the advantages of the approach over traditional geostatistical methods are revealed and discussed. The new approach also quantifies the effectiveness of soil sampling on reduction of uncertainty levels across the site. This can become a useful indicator for risk management or mitigation strategies, as it is often necessary to balance between the available reSources for soil sampling at the site and the needs for proper characterization of contaminant distributions.
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arsenic containing soil from Geogenic Source in hong kong leaching characteristics and stabilization solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
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Arsenic-containing soil from Geogenic Source in Hong Kong: Leaching characteristics and stabilization/solidification
Chemosphere, 2017Co-Authors: Jiangshan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiangdong Li, Scott FendorfAbstract:Geogenic Sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486–1985 mg kg−1) were mostly encountered in deeper layer (15–20 m below ground). Despite high concentrations, Geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.