The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show tha...The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show that the release law of Cd and Pb in sediments is divided into two stages:rapid release and dynamic equilibrium,which is in great agreement with the pseudo second-order kinetic equation with a correlation coefficient R2 above 0.99.As the flow velocity accelerates,the release rate of heavy metals increases.The analysis results indicate that the water quality in the area can exceed the surface water Class V standard less than 3 h,and all but one of the relative deviations between the simulation value and the field survey result are within±10%.展开更多
The aim of this study is to describe the sedimentary evolution occurred during the last 200-years in the middle Capibaribe Estuary by mean of the sedimentary analysis (magnetic susceptibility, grain size, calcium carb...The aim of this study is to describe the sedimentary evolution occurred during the last 200-years in the middle Capibaribe Estuary by mean of the sedimentary analysis (magnetic susceptibility, grain size, calcium carbonate, total organic matter—TOM) and geochemical parameters (sedimentation rates, heavy metal concentrations, enrichment and contamination factor) along a core. The core recorded four units and the measured sedimentation rate was 0.52 cm cm·y﹣1. The first unit, dating before 1812, showed environmental characteristics of mangrove with predominance of fine sediments, high total organic matter percentages and heavy metal concentrations probably from natural sources. The second unit, from 1812 to 1937, showed a slight increase in sand percentages and decrease in fine fraction, TOM contents and heavy metals concentrations. These characteristics may be associated with the urban expansion processes and the presence of monoculture of sugar cane occurred in the middle Capibaribe Estuary. The third unit, from 1937 to 2004, showed the highest sand percentages of the core, characterizing a unit exclusively of sand with low fine fractions percentages, total organic matter contents and heavy metals concentrations. This unit represented the intensification of the urban processes expansion of Recife City. The fourth unit showed increases in fine fraction sedimentation, TOM contents and heavy metals concentrations. This new change in sedimentation probably is consequence of rebirth of marginal estuarine banks by mangrove vegetation, due to environmental projects carried out by Recife Prefecture in the early 2000’s. It was not possible to register the anthropic contamination to middle estuary area probably due to the Barreiras Formation influences in the metal concentration records, masking the anthropic contamination inputs in estuarine region. Although, lead and arsenic showing an enrichment level indicating anthropic contamination.展开更多
The sedimentation of metals can preserve the historical record of contaminant input from local and regional sources and provide information on the historical changes in regionalwater and sediment quality. We report th...The sedimentation of metals can preserve the historical record of contaminant input from local and regional sources and provide information on the historical changes in regionalwater and sediment quality. We report the 210Pb activities and the heavy metal （Cd, Cr, Cu, Mn, Pb and Zn）depth profiles from sediment cores retrieved in 2010. The mean sedimentation rates of 0.85-1.5 cm/yr aredetermined by 210 Pbdating. The sediments in the tidal flat have recorded heavy metaldeposition and thus allow the establishment of a connection between the temporal evolution of the heavy metal pollution and the historical changes in the economicdevelopment of Lianyungang. The enrichment factors （EF） are calculated to estimate the level of contamination stored in these sediments. The results show that in the studied sites, Cr and Cudisplay low EF values and are mainly from lithogenic origin. For the other studied trace metals, a great variability in the sedimentary record is observed. Significant anthropogenic enrichment over the last 50 years is revealed at the tidal flat that receives fluvial inputs. Zinc is the elementwith the highest EF values, followed by the order of Pb 〉 Cd 〉 Mn 〉 Cu and Cr. The temporal variations of the heavy metals peakduring the late 1980s to the early2000s and show adecreasing trend afterward. The pollution intensity of the tidal flat isdetermined by using EF and thegeo-accumulation index （Igeo ）,which show that, based on the Igeo scale, the tidal flat of Haizhou Bay is unpolluted to moderately polluted.展开更多
The bottom surface sediments at the southern part of the Jordanian coast of the Gulf of Aqaba have been studied. Samples were collected from 10 m depth at nine coastal stations which are located within two main zones:...The bottom surface sediments at the southern part of the Jordanian coast of the Gulf of Aqaba have been studied. Samples were collected from 10 m depth at nine coastal stations which are located within two main zones: Marine Park Zone and Industrial Zone. Sedimentation rate, grain size oxygenation state, Loss on Ignition, hydrogen sulfide, calcium carbonate, total phosphorous, organic carbon, organic nitrogen, and heavy metals were analyzed to assess and evaluate the quality of bottom surface sediments. The sedimentation rate at the southern part of the Gulf has been affected by Khamassin winds from the south as a result of sand storm events in southern Jordan and adjacent regions. Floods and streams also played a vital role as a transportation agent of the sediments from the interstitial nearby areas to the Gulf. Also construction works played a minor role. Bottom surface sediments at the different sites were quite different in some chemical properties. Sediments from all stations other than the MSS were fine, gray-black and oxygen deficient. Sediments from the MSS and VC are whitish, better oxygenated and have higher calcium carbonate content since they are typically coral reef sediments coral reef sediments. Coral reef carbonate sediments are well known to have high organic nitrogen concentration as compared to silicate sediments, even those in close proximity. The concentration of phosphorous and calcium carbonate is attributed in the phosphate port to the phosphate by the generation of the dust and coral reef. Whilst, heavy metal concentration due to presence of major sources of metal pollution and intensive human activities. These include ship boat activities, domestic sewage discharges and phosphate rock particles from the phosphate port.展开更多
基金The authors are grateful for the financial supports from the National Key R&D Program of China(2018YFC1903301).
文摘The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show that the release law of Cd and Pb in sediments is divided into two stages:rapid release and dynamic equilibrium,which is in great agreement with the pseudo second-order kinetic equation with a correlation coefficient R2 above 0.99.As the flow velocity accelerates,the release rate of heavy metals increases.The analysis results indicate that the water quality in the area can exceed the surface water Class V standard less than 3 h,and all but one of the relative deviations between the simulation value and the field survey result are within±10%.
文摘The aim of this study is to describe the sedimentary evolution occurred during the last 200-years in the middle Capibaribe Estuary by mean of the sedimentary analysis (magnetic susceptibility, grain size, calcium carbonate, total organic matter—TOM) and geochemical parameters (sedimentation rates, heavy metal concentrations, enrichment and contamination factor) along a core. The core recorded four units and the measured sedimentation rate was 0.52 cm cm·y﹣1. The first unit, dating before 1812, showed environmental characteristics of mangrove with predominance of fine sediments, high total organic matter percentages and heavy metal concentrations probably from natural sources. The second unit, from 1812 to 1937, showed a slight increase in sand percentages and decrease in fine fraction, TOM contents and heavy metals concentrations. These characteristics may be associated with the urban expansion processes and the presence of monoculture of sugar cane occurred in the middle Capibaribe Estuary. The third unit, from 1937 to 2004, showed the highest sand percentages of the core, characterizing a unit exclusively of sand with low fine fractions percentages, total organic matter contents and heavy metals concentrations. This unit represented the intensification of the urban processes expansion of Recife City. The fourth unit showed increases in fine fraction sedimentation, TOM contents and heavy metals concentrations. This new change in sedimentation probably is consequence of rebirth of marginal estuarine banks by mangrove vegetation, due to environmental projects carried out by Recife Prefecture in the early 2000’s. It was not possible to register the anthropic contamination to middle estuary area probably due to the Barreiras Formation influences in the metal concentration records, masking the anthropic contamination inputs in estuarine region. Although, lead and arsenic showing an enrichment level indicating anthropic contamination.
基金supported by the Open Fund of State Key Laboratory of Pollution Control and Resources Reuse(No.PCRRF11024)the Fostering Project of Major Research Plan of National Natural Sciences Foundation of China(No.91025022)+3 种基金the Natural Science Foundation of Huaihai Institute of Technology(No.Z2011001)the Priming Scientific Research Foundation for the Junior Teachersin Huaihai Institute of Technology(No.KQ09041)the Project of Innovation from Undergraduate in Jiangsu Province(No.SY201311641107001) the project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The sedimentation of metals can preserve the historical record of contaminant input from local and regional sources and provide information on the historical changes in regionalwater and sediment quality. We report the 210Pb activities and the heavy metal （Cd, Cr, Cu, Mn, Pb and Zn）depth profiles from sediment cores retrieved in 2010. The mean sedimentation rates of 0.85-1.5 cm/yr aredetermined by 210 Pbdating. The sediments in the tidal flat have recorded heavy metaldeposition and thus allow the establishment of a connection between the temporal evolution of the heavy metal pollution and the historical changes in the economicdevelopment of Lianyungang. The enrichment factors （EF） are calculated to estimate the level of contamination stored in these sediments. The results show that in the studied sites, Cr and Cudisplay low EF values and are mainly from lithogenic origin. For the other studied trace metals, a great variability in the sedimentary record is observed. Significant anthropogenic enrichment over the last 50 years is revealed at the tidal flat that receives fluvial inputs. Zinc is the elementwith the highest EF values, followed by the order of Pb 〉 Cd 〉 Mn 〉 Cu and Cr. The temporal variations of the heavy metals peakduring the late 1980s to the early2000s and show adecreasing trend afterward. The pollution intensity of the tidal flat isdetermined by using EF and thegeo-accumulation index （Igeo ）,which show that, based on the Igeo scale, the tidal flat of Haizhou Bay is unpolluted to moderately polluted.
文摘The bottom surface sediments at the southern part of the Jordanian coast of the Gulf of Aqaba have been studied. Samples were collected from 10 m depth at nine coastal stations which are located within two main zones: Marine Park Zone and Industrial Zone. Sedimentation rate, grain size oxygenation state, Loss on Ignition, hydrogen sulfide, calcium carbonate, total phosphorous, organic carbon, organic nitrogen, and heavy metals were analyzed to assess and evaluate the quality of bottom surface sediments. The sedimentation rate at the southern part of the Gulf has been affected by Khamassin winds from the south as a result of sand storm events in southern Jordan and adjacent regions. Floods and streams also played a vital role as a transportation agent of the sediments from the interstitial nearby areas to the Gulf. Also construction works played a minor role. Bottom surface sediments at the different sites were quite different in some chemical properties. Sediments from all stations other than the MSS were fine, gray-black and oxygen deficient. Sediments from the MSS and VC are whitish, better oxygenated and have higher calcium carbonate content since they are typically coral reef sediments coral reef sediments. Coral reef carbonate sediments are well known to have high organic nitrogen concentration as compared to silicate sediments, even those in close proximity. The concentration of phosphorous and calcium carbonate is attributed in the phosphate port to the phosphate by the generation of the dust and coral reef. Whilst, heavy metal concentration due to presence of major sources of metal pollution and intensive human activities. These include ship boat activities, domestic sewage discharges and phosphate rock particles from the phosphate port.
