The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Lei Zhang - One of the best experts on this subject based on the ideXlab platform.
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evaluation of simulated Dredging to control internal phosphorus release from sediments focused on phosphorus transfer and resupply across the sediment water interface
Science of The Total Environment, 2017Co-Authors: Juhua Yu, Jicheng Zhong, Lei Zhang, Shiming Ding, Qiuwen Chen, Yinlong ZhangAbstract:Sediment Dredging is an effective restoration method to control the internal phosphorus (P) loading of eutrophic lakes. However, the core question is that the real mechanism of Dredging responsible for sediment internal P release still remains unclear. In this study, we investigated the P exchange across the sediment-water interface (SWI) and the internal P resupply ability from the sediments after Dredging. The study is based on a one-year field simulation study in Lake Taihu, China, using a Rhizon soil moisture sampler, high-resolution dialysis (HR-Peeper), ZrO-Chelex diffusive gradients in thin film (ZrO-Chelex DGT), and P fractionation and adsorption isotherm techniques. The results showed low concentration of labile P in the pore water with a low diffusion potential and a low resupply ability from the sediments after Dredging. The calculated flux of P from the post-dredged sediments decreased by 58% compared with that of non-dredged sediments. Furthermore, the resupply in the upper 20mm of the post-dredged sediments was reduced significantly after Dredging (P<0.001). Phosphorus fractionation analysis showed a reduction of 25% in the mobile P fractions in the post-dredged sediments. Further analysis demonstrated that the zero equilibrium P concentration (EPC0), partitioning coefficient (Kp), and adsorption capacity (Qmax) on the surface sediments increased after Dredging. Therefore, Dredging could effectively reduce the internal P resupply ability of the sediments. The reasons for this reduction are probably the lower contributions of mobile P fractions, higher retention ability, and the adsorption capacity of P for post-dredged sediments. Overall, this investigation indicated that Dredging was capable of effectively controlling sediment internal P release, which could be ascribed to the removal of the surface sediments enriched with total phosphorus (TP) and/or organic matter (OM), coupled with the inactivation of P to iron (Fe) (hydr)oxides in the upper 20mm active layer.
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evaluation of in situ simulated Dredging to reduce internal nitrogen flux across the sediment water interface in lake taihu china
Environmental Pollution, 2016Co-Authors: Juhua Yu, Jicheng Zhong, Yinlong Zhang, Changhui Wang, Lei ZhangAbstract:Abstract Sediment Dredging is considered an effective restoration method to reduce internal loading of nitrogen (N) and phosphorus (P) in eutrophic lakes. However, the effect of Dredging on N release from sediments to overlying water is not well understood. In this study, N exchange and regeneration across the sediment-water interface (SWI) were investigated based on a one-year simulated Dredging study in Lake Taihu, China. The results showed low concentrations of inorganic N in pore water with low mobilization from the sediments after Dredging. The calculated fluxes of NO 3 − -N from post-dredged sediments to overlying water significantly increased by 58% ( p 4 + -N dramatically decreased by 78.2% after Dredging ( p Nitrospira enhanced, although the relative abundance of Thiobacillus , Sterolibacterium , Denitratisoma , Hyphomicrobium , Anaeromyxobacter and Caldithrix generally declined after Dredging. Therefore, Dredging reduced N mobilization from the sediments, which primarily due to decreases in N mobility, in organic matter (OM) mineralization potential and in the bacterial abundance of post-dredged sediments. Overall, to minimize internal N pollution, Dredging is capable of effectively reducing N release from sediments. In addition, the negative side effect of Dredging on removal of NO 3 − -N and NO 2 − -N from aquatic ecosystems should be paid much more attention in future.
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effects of riverine suspended particulate matter on post Dredging metal re contamination across the sediment water interface
Chemosphere, 2016Co-Authors: Qiushi Shen, Lei Zhang, Shiguang Shao, Qilin ZhouAbstract:Abstract Environmental Dredging is often used in river mouth areas to remove heavy metals. However, following Dredging, high levels of metal-adsorbed suspended particulate matter (SPM) originating from polluted inflowing rivers might adversely affect the sediment–water interface (SWI). Here, we conducted a 360-day-long experiment investigating whether the riverine SPM adversely affects Dredging outcome in a bay area of Lake Chaohu, China. We found that the heavy metal concentrations in the post-Dredging surface sediment increased to pre-Dredging levels for all metals studied (As, Cd, Cr, Cu, Ni, Pb, and Zn) after the addition of SPM. In addition, the increased concentrations were mostly detected in the relatively bioavailable non-residual fractions. Of the metals studied, the rate of increase was the greatest for Zn and Cd (482.98% and 261.07%, respectively), mostly in the weak acid extractable fraction. These results were probably due to certain characteristics of SPM (fine grain size, and high concentrations of organic matter and heavy metals) and the good oxic conditions of the SWI. Furthermore, As was the only metal for which we observed an increasing trend of diffusive flux across the SWI. However, the flux was still significantly lower than that measured before Dredging. In conclusion, the quantity and character of riverine metal-adsorbed SPM affect metal re-contamination across the post-Dredging SWI, and this information should be incorporated into the management schemes of Dredging projects dedicated to reducing metal contamination in similar areas.
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effects of sediment Dredging on nitrogen cycling in lake taihu china insight from mass balance based on a 2 year field study
Environmental Science and Pollution Research, 2016Co-Authors: Juhua Yu, Jicheng Zhong, Lei Zhang, Lu Zhang, Changhui WangAbstract:Sediment Dredging can permanently remove pollutants from an aquatic ecosystem, which is considered an effective approach to aquatic ecosystem restoration. In this work, a 2-year field simulation test was carried out to investigate the effect of Dredging on nitrogen cycling across the sediment-water interface (SWI) in Lake Taihu, China. The results showed that simulated Dredging applied to an area rich in total organic carbon (TOC) and total nitrogen (TN) slightly reduced the NH4 +-N release from sediments while temporarily enhanced the NH4 +-N release in an area with lower TOC and/or TN (in the first 180 days), although the application had a limited effect on the fluxes of NO2 −-N and NO3 −-N in both areas. Further analysis indicated that Dredging induced decreases in nitrification, denitrification, and anaerobic ammonium oxidation (anammox) in sediments, notably by 76.9, 49.0, and 89.9 %, respectively, in the TOC and/or TN-rich area. Therefore, Dredging slowed down nitrogen cycling rates in sediments but did not increase N loading to overlying water. The main reason for the above phenomenon could be attributed to the removal of the surface sediments enriched with more TOC and/or TN (compared with the bottom sediments). Overall, to minimize internal N pollution, Dredging may be more applicable to nutrient-rich sediments.
Jicheng Zhong - One of the best experts on this subject based on the ideXlab platform.
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exchanges of nitrogen and phosphorus across the sediment water interface influenced by the external suspended particulate matter and the residual matter after Dredging
Environmental Pollution, 2019Co-Authors: Jicheng Zhong, Yiheng Du, Kaining Chen, Xiaozhi GuAbstract:Abstract Dredging is frequently implemented for the reduction of internal nitrogen (N) and phosphorus (P) loadings and the control of eutrophication. Residuals during Dredging activities and external pollution loadings after Dredging both commonly contribute to influence the effectiveness of Dredging and have been widely discussed. In the current study, the exchanges of N and P across the sediment-water interface (SWI) to these two factors were compared in a six-month field incubation experiment. The results showed that the continuous deposition of external suspended particulate matter (SPM) led ammonium nitrogen (NH4+ N) and soluble reactive phosphorus (SRP) fluxes across the newly formed SWI to increase by factors of 4.16 and 12.71, respectively, while residual material caused the same fluxes to increase by factors of 2.06 and 5.06. Both the deposition of external SPM and the residual matter led to higher increase of the fluxes of P across the SWI than those of the fluxes of N across the SWI after Dredging. The SPM easily adsorbed P in the water due to extensive adsorption of water soluble organic matter (consisting primarily of easily-decomposed humic-like substances), iron, and aluminum. However, the decomposition of organic matter in the SPM after the deposition on the dredged sediment accelerated the dissolution of redox-sensitive P and organic P across the SWI after Dredging. Both the increase in the fluxes of N and P across the SWI would further increase the concentrations of N and P in the overlying water and thereby aggravate the eutrophication status in lakes. More frequent Dredging operations might be necessary to reduce the fluxes of N and P from the sediment due to the continuous influence of the external SPM and the residual matter.
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evaluation of simulated Dredging to control internal phosphorus release from sediments focused on phosphorus transfer and resupply across the sediment water interface
Science of The Total Environment, 2017Co-Authors: Juhua Yu, Jicheng Zhong, Lei Zhang, Shiming Ding, Qiuwen Chen, Yinlong ZhangAbstract:Sediment Dredging is an effective restoration method to control the internal phosphorus (P) loading of eutrophic lakes. However, the core question is that the real mechanism of Dredging responsible for sediment internal P release still remains unclear. In this study, we investigated the P exchange across the sediment-water interface (SWI) and the internal P resupply ability from the sediments after Dredging. The study is based on a one-year field simulation study in Lake Taihu, China, using a Rhizon soil moisture sampler, high-resolution dialysis (HR-Peeper), ZrO-Chelex diffusive gradients in thin film (ZrO-Chelex DGT), and P fractionation and adsorption isotherm techniques. The results showed low concentration of labile P in the pore water with a low diffusion potential and a low resupply ability from the sediments after Dredging. The calculated flux of P from the post-dredged sediments decreased by 58% compared with that of non-dredged sediments. Furthermore, the resupply in the upper 20mm of the post-dredged sediments was reduced significantly after Dredging (P<0.001). Phosphorus fractionation analysis showed a reduction of 25% in the mobile P fractions in the post-dredged sediments. Further analysis demonstrated that the zero equilibrium P concentration (EPC0), partitioning coefficient (Kp), and adsorption capacity (Qmax) on the surface sediments increased after Dredging. Therefore, Dredging could effectively reduce the internal P resupply ability of the sediments. The reasons for this reduction are probably the lower contributions of mobile P fractions, higher retention ability, and the adsorption capacity of P for post-dredged sediments. Overall, this investigation indicated that Dredging was capable of effectively controlling sediment internal P release, which could be ascribed to the removal of the surface sediments enriched with total phosphorus (TP) and/or organic matter (OM), coupled with the inactivation of P to iron (Fe) (hydr)oxides in the upper 20mm active layer.
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evaluation of in situ simulated Dredging to reduce internal nitrogen flux across the sediment water interface in lake taihu china
Environmental Pollution, 2016Co-Authors: Juhua Yu, Jicheng Zhong, Yinlong Zhang, Changhui Wang, Lei ZhangAbstract:Abstract Sediment Dredging is considered an effective restoration method to reduce internal loading of nitrogen (N) and phosphorus (P) in eutrophic lakes. However, the effect of Dredging on N release from sediments to overlying water is not well understood. In this study, N exchange and regeneration across the sediment-water interface (SWI) were investigated based on a one-year simulated Dredging study in Lake Taihu, China. The results showed low concentrations of inorganic N in pore water with low mobilization from the sediments after Dredging. The calculated fluxes of NO 3 − -N from post-dredged sediments to overlying water significantly increased by 58% ( p 4 + -N dramatically decreased by 78.2% after Dredging ( p Nitrospira enhanced, although the relative abundance of Thiobacillus , Sterolibacterium , Denitratisoma , Hyphomicrobium , Anaeromyxobacter and Caldithrix generally declined after Dredging. Therefore, Dredging reduced N mobilization from the sediments, which primarily due to decreases in N mobility, in organic matter (OM) mineralization potential and in the bacterial abundance of post-dredged sediments. Overall, to minimize internal N pollution, Dredging is capable of effectively reducing N release from sediments. In addition, the negative side effect of Dredging on removal of NO 3 − -N and NO 2 − -N from aquatic ecosystems should be paid much more attention in future.
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effects of sediment Dredging on nitrogen cycling in lake taihu china insight from mass balance based on a 2 year field study
Environmental Science and Pollution Research, 2016Co-Authors: Juhua Yu, Jicheng Zhong, Lei Zhang, Lu Zhang, Changhui WangAbstract:Sediment Dredging can permanently remove pollutants from an aquatic ecosystem, which is considered an effective approach to aquatic ecosystem restoration. In this work, a 2-year field simulation test was carried out to investigate the effect of Dredging on nitrogen cycling across the sediment-water interface (SWI) in Lake Taihu, China. The results showed that simulated Dredging applied to an area rich in total organic carbon (TOC) and total nitrogen (TN) slightly reduced the NH4 +-N release from sediments while temporarily enhanced the NH4 +-N release in an area with lower TOC and/or TN (in the first 180 days), although the application had a limited effect on the fluxes of NO2 −-N and NO3 −-N in both areas. Further analysis indicated that Dredging induced decreases in nitrification, denitrification, and anaerobic ammonium oxidation (anammox) in sediments, notably by 76.9, 49.0, and 89.9 %, respectively, in the TOC and/or TN-rich area. Therefore, Dredging slowed down nitrogen cycling rates in sediments but did not increase N loading to overlying water. The main reason for the above phenomenon could be attributed to the removal of the surface sediments enriched with more TOC and/or TN (compared with the bottom sediments). Overall, to minimize internal N pollution, Dredging may be more applicable to nutrient-rich sediments.
Xiaozhi Gu - One of the best experts on this subject based on the ideXlab platform.
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exchanges of nitrogen and phosphorus across the sediment water interface influenced by the external suspended particulate matter and the residual matter after Dredging
Environmental Pollution, 2019Co-Authors: Jicheng Zhong, Yiheng Du, Kaining Chen, Xiaozhi GuAbstract:Abstract Dredging is frequently implemented for the reduction of internal nitrogen (N) and phosphorus (P) loadings and the control of eutrophication. Residuals during Dredging activities and external pollution loadings after Dredging both commonly contribute to influence the effectiveness of Dredging and have been widely discussed. In the current study, the exchanges of N and P across the sediment-water interface (SWI) to these two factors were compared in a six-month field incubation experiment. The results showed that the continuous deposition of external suspended particulate matter (SPM) led ammonium nitrogen (NH4+ N) and soluble reactive phosphorus (SRP) fluxes across the newly formed SWI to increase by factors of 4.16 and 12.71, respectively, while residual material caused the same fluxes to increase by factors of 2.06 and 5.06. Both the deposition of external SPM and the residual matter led to higher increase of the fluxes of P across the SWI than those of the fluxes of N across the SWI after Dredging. The SPM easily adsorbed P in the water due to extensive adsorption of water soluble organic matter (consisting primarily of easily-decomposed humic-like substances), iron, and aluminum. However, the decomposition of organic matter in the SPM after the deposition on the dredged sediment accelerated the dissolution of redox-sensitive P and organic P across the SWI after Dredging. Both the increase in the fluxes of N and P across the SWI would further increase the concentrations of N and P in the overlying water and thereby aggravate the eutrophication status in lakes. More frequent Dredging operations might be necessary to reduce the fluxes of N and P from the sediment due to the continuous influence of the external SPM and the residual matter.
Juhua Yu - One of the best experts on this subject based on the ideXlab platform.
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evaluation of simulated Dredging to control internal phosphorus release from sediments focused on phosphorus transfer and resupply across the sediment water interface
Science of The Total Environment, 2017Co-Authors: Juhua Yu, Jicheng Zhong, Lei Zhang, Shiming Ding, Qiuwen Chen, Yinlong ZhangAbstract:Sediment Dredging is an effective restoration method to control the internal phosphorus (P) loading of eutrophic lakes. However, the core question is that the real mechanism of Dredging responsible for sediment internal P release still remains unclear. In this study, we investigated the P exchange across the sediment-water interface (SWI) and the internal P resupply ability from the sediments after Dredging. The study is based on a one-year field simulation study in Lake Taihu, China, using a Rhizon soil moisture sampler, high-resolution dialysis (HR-Peeper), ZrO-Chelex diffusive gradients in thin film (ZrO-Chelex DGT), and P fractionation and adsorption isotherm techniques. The results showed low concentration of labile P in the pore water with a low diffusion potential and a low resupply ability from the sediments after Dredging. The calculated flux of P from the post-dredged sediments decreased by 58% compared with that of non-dredged sediments. Furthermore, the resupply in the upper 20mm of the post-dredged sediments was reduced significantly after Dredging (P<0.001). Phosphorus fractionation analysis showed a reduction of 25% in the mobile P fractions in the post-dredged sediments. Further analysis demonstrated that the zero equilibrium P concentration (EPC0), partitioning coefficient (Kp), and adsorption capacity (Qmax) on the surface sediments increased after Dredging. Therefore, Dredging could effectively reduce the internal P resupply ability of the sediments. The reasons for this reduction are probably the lower contributions of mobile P fractions, higher retention ability, and the adsorption capacity of P for post-dredged sediments. Overall, this investigation indicated that Dredging was capable of effectively controlling sediment internal P release, which could be ascribed to the removal of the surface sediments enriched with total phosphorus (TP) and/or organic matter (OM), coupled with the inactivation of P to iron (Fe) (hydr)oxides in the upper 20mm active layer.
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evaluation of in situ simulated Dredging to reduce internal nitrogen flux across the sediment water interface in lake taihu china
Environmental Pollution, 2016Co-Authors: Juhua Yu, Jicheng Zhong, Yinlong Zhang, Changhui Wang, Lei ZhangAbstract:Abstract Sediment Dredging is considered an effective restoration method to reduce internal loading of nitrogen (N) and phosphorus (P) in eutrophic lakes. However, the effect of Dredging on N release from sediments to overlying water is not well understood. In this study, N exchange and regeneration across the sediment-water interface (SWI) were investigated based on a one-year simulated Dredging study in Lake Taihu, China. The results showed low concentrations of inorganic N in pore water with low mobilization from the sediments after Dredging. The calculated fluxes of NO 3 − -N from post-dredged sediments to overlying water significantly increased by 58% ( p 4 + -N dramatically decreased by 78.2% after Dredging ( p Nitrospira enhanced, although the relative abundance of Thiobacillus , Sterolibacterium , Denitratisoma , Hyphomicrobium , Anaeromyxobacter and Caldithrix generally declined after Dredging. Therefore, Dredging reduced N mobilization from the sediments, which primarily due to decreases in N mobility, in organic matter (OM) mineralization potential and in the bacterial abundance of post-dredged sediments. Overall, to minimize internal N pollution, Dredging is capable of effectively reducing N release from sediments. In addition, the negative side effect of Dredging on removal of NO 3 − -N and NO 2 − -N from aquatic ecosystems should be paid much more attention in future.
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effects of sediment Dredging on nitrogen cycling in lake taihu china insight from mass balance based on a 2 year field study
Environmental Science and Pollution Research, 2016Co-Authors: Juhua Yu, Jicheng Zhong, Lei Zhang, Lu Zhang, Changhui WangAbstract:Sediment Dredging can permanently remove pollutants from an aquatic ecosystem, which is considered an effective approach to aquatic ecosystem restoration. In this work, a 2-year field simulation test was carried out to investigate the effect of Dredging on nitrogen cycling across the sediment-water interface (SWI) in Lake Taihu, China. The results showed that simulated Dredging applied to an area rich in total organic carbon (TOC) and total nitrogen (TN) slightly reduced the NH4 +-N release from sediments while temporarily enhanced the NH4 +-N release in an area with lower TOC and/or TN (in the first 180 days), although the application had a limited effect on the fluxes of NO2 −-N and NO3 −-N in both areas. Further analysis indicated that Dredging induced decreases in nitrification, denitrification, and anaerobic ammonium oxidation (anammox) in sediments, notably by 76.9, 49.0, and 89.9 %, respectively, in the TOC and/or TN-rich area. Therefore, Dredging slowed down nitrogen cycling rates in sediments but did not increase N loading to overlying water. The main reason for the above phenomenon could be attributed to the removal of the surface sediments enriched with more TOC and/or TN (compared with the bottom sediments). Overall, to minimize internal N pollution, Dredging may be more applicable to nutrient-rich sediments.
Yiheng Du - One of the best experts on this subject based on the ideXlab platform.
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exchanges of nitrogen and phosphorus across the sediment water interface influenced by the external suspended particulate matter and the residual matter after Dredging
Environmental Pollution, 2019Co-Authors: Jicheng Zhong, Yiheng Du, Kaining Chen, Xiaozhi GuAbstract:Abstract Dredging is frequently implemented for the reduction of internal nitrogen (N) and phosphorus (P) loadings and the control of eutrophication. Residuals during Dredging activities and external pollution loadings after Dredging both commonly contribute to influence the effectiveness of Dredging and have been widely discussed. In the current study, the exchanges of N and P across the sediment-water interface (SWI) to these two factors were compared in a six-month field incubation experiment. The results showed that the continuous deposition of external suspended particulate matter (SPM) led ammonium nitrogen (NH4+ N) and soluble reactive phosphorus (SRP) fluxes across the newly formed SWI to increase by factors of 4.16 and 12.71, respectively, while residual material caused the same fluxes to increase by factors of 2.06 and 5.06. Both the deposition of external SPM and the residual matter led to higher increase of the fluxes of P across the SWI than those of the fluxes of N across the SWI after Dredging. The SPM easily adsorbed P in the water due to extensive adsorption of water soluble organic matter (consisting primarily of easily-decomposed humic-like substances), iron, and aluminum. However, the decomposition of organic matter in the SPM after the deposition on the dredged sediment accelerated the dissolution of redox-sensitive P and organic P across the SWI after Dredging. Both the increase in the fluxes of N and P across the SWI would further increase the concentrations of N and P in the overlying water and thereby aggravate the eutrophication status in lakes. More frequent Dredging operations might be necessary to reduce the fluxes of N and P from the sediment due to the continuous influence of the external SPM and the residual matter.
