Hydrocarbon contamination from oil spills presents geoenvironmental and geoengineering challenges,notably in Eleme,Nigeria.This study integrates electrical resistivity tomography(ERT),soil total petroleum hydrocarbon(...Hydrocarbon contamination from oil spills presents geoenvironmental and geoengineering challenges,notably in Eleme,Nigeria.This study integrates electrical resistivity tomography(ERT),soil total petroleum hydrocarbon(TPH)analysis,and geotechnical testing for treated spill site monitoring and characterization over six months.Four 100 m ERT lines,L1 to L4,with spacings at 1.5 m,3 m,6 m,9 m,12 m,and 15 m,were established for the first and second sampling phases.Twenty-one soil samples,12 TPH,and 9 mechanical analyses,were obtained from 5 boreholes,BH1 to BH4,for the study site and the BH5 control site across the phases at 0.5 m,3.0 m,and 5.0 m depths along ERT lines.ERT results reveal resistivity reductions averaging 18%in shallow zones of active degradation,correlating with an average 41%TPH-decrease.Specific gravity averaged 2.49 in the spill soils,compared to 2.58 in control samples,reflecting hydrocarbon-induced density reductions of 3.5%.Particle size showed spill soils contained>50%fines,increasing water retention and reducing permeability by 30%.Consolidation tests highlighted increased compressibility,with settlements of 1.89 mm in spill soils versus 1.01 mm in control samples,indicating a 47%increase in settlement from hydrocarbon reduction.Correlation analysis shows slower consolidation at BH3(−0.62 Cv)with moderate settlement increase(0.25),while BH4 exhibits much higher compressibility(0.95)but minimal Cv impact(0.23),indicating increased structural weakness with higher residual TPH.Spill degradation reduced TPH by 19%-64%in shallow zones,with persistent contamination at deeper layers exceeding the regulatory limits,emphasising the need for ongoing monitoring and targeted remediation for long-term stability and sustainability.展开更多
This work focused on the prediction modeling of Cerrado occurrences in the Atlantic Rainforest predominance in the São Paulo Metropolitan Region (SPMR), the fourth largest urban area, in the city of Guarulhos...This work focused on the prediction modeling of Cerrado occurrences in the Atlantic Rainforest predominance in the São Paulo Metropolitan Region (SPMR), the fourth largest urban area, in the city of Guarulhos, southeastern Brazil. The methodology was based on the selection of records of occurrence of Cerrado in georeferenced databases, thematic maps of geoenvironmental layers, and modeling of the distribution of species through the MaxEnt tool. Besides that, field research confirmed the presence or not of the species in the areas with a high probability of occurrence of Cerrado (≥0.7). As a result, the model observed a great capacity for the prediction of the occurrence of Cerrado in Ecotonal and anthropic regions (AUC = 0.82), revealing important hotspots such as relics from the past or Cerrado enclaves of high biodiversity. The work also points priority areas for the conservation and preservation of this increasingly endangered biome.展开更多
The north-south trending Kullu valley between Rohtang in the north and Hansu in the south is a wide and open valley filled with Quaternary sediments along the main eourse of the Beas River. The valley in the middle is...The north-south trending Kullu valley between Rohtang in the north and Hansu in the south is a wide and open valley filled with Quaternary sediments along the main eourse of the Beas River. The valley in the middle is drained by the Beas River and numerous tributaries join it laterally. The tributary ehannels have deposited large alluvial fans at their mouths whieh form three distinct levels. The Beas River has deposited alluvial terraees, whieh are very distinct towards the lower reaehes and form three to four levels. The upper slopes and high altitudinal areas are eovered with periglaeial and glaeial deposits. The terraee, fan and hill slopes have provided an ideal geoenvironment for human aetivities inehiding agrieulture, hortieulture, dense settlements and other eivil establishments. The Kulhi Valley is prone to various natural hazards, flash floods and eloudbursts that are very eommon in this valley due to its peeuliar geomorphie eonclifton, high relief of peripheral ridges and impact of monsoon winds. The studies carried out so far indicate that the losses caused by these phenomena both in terms of life and property are mainly due to unwise human interaction with the geoenvironment of the area. The paper gives an overview of the geoenvironmental status of the Kulhi Valley and suggests the necessity of undertaking further detailed studies ineluding resouree mapping for balaneed development of the area.展开更多
This study is conducted to evaluate the ongoing geoenvironmental impacts of Brahmaputra-Jamuna (BJ) River around the Jamuna Bridge (JB) site which was modified prior to the construction of Jamuna Bridge in 1996. Remot...This study is conducted to evaluate the ongoing geoenvironmental impacts of Brahmaputra-Jamuna (BJ) River around the Jamuna Bridge (JB) site which was modified prior to the construction of Jamuna Bridge in 1996. Remote sensing and GIS techniques are adopted to evaluate the temporal and spatial geohazards. This study shows that the intensity of channel shifting has been increased due to regulation of river width at Sira-jganj–Bhuiyapur section from 11 km to 4.8 km. Planform analysis shows that the major channel has been stressed to migrate (315 m/year) eastwards. The phenomena of channel changes are predicted to be the con-sequences of interaction of water flow, sedimentation and channel corridor. The erosion and deposition have complicated variations over time and space due to the abrupt changes of flow and sedimentation around the regulated section. Due to width reduction, the bridge site in the braided system acts as sluice gate which can not accommodate the entire flow to release downstream properly. The helical flow developed with the inter-action of guide bund creates local scours and helps to shift the river bank eastward.展开更多
Expansive soils are problematic due to the performances of their clay mineral constituent, which makes them exhibit the shrink-swell characteristics. The shrink-swell behaviours make expansive soils inappropriate for ...Expansive soils are problematic due to the performances of their clay mineral constituent, which makes them exhibit the shrink-swell characteristics. The shrink-swell behaviours make expansive soils inappropriate for direct engineering application in their natural form. In an attempt to make them more feasible for construction purposes, numerous materials and techniques have been used to stabilise the soil. In this study, the additives and techniques applied for stabilising expansive soils will be focused on,with respect to their efficiency in improving the engineering properties of the soils. Then we discussed the microstructural interaction, chemical process, economic implication, nanotechnology application, as well as waste reuse and sustainability. Some issues regarding the effective application of the emerging trends in expansive soil stabilisation were presented with three categories, namely geoenvironmental,standardisation and optimisation issues. Techniques like predictive modelling and exploring methods such as reliability-based design optimisation, response surface methodology, dimensional analysis, and artificial intelligence technology were also proposed in order to ensure that expansive soil stabilisation is efficient.展开更多
Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the p...Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the placers, as well as the poor assimilative capacity of the natural systems can result in serious environmental impacts in the area. The primary geochemical processes in the diamond-bearing area are affected by the occurrence of permafrost and relict ice, the lengthy duration of ice cover in water bodies, and the widespread development of cryogenic processes. This promotes physical migration of contaminants, cryogenic metamorphization of waters, and long-term accumulation of organic contaminants in low-temperature, reduction and sedimentation barriers. In this paper, some environmental and geochemical effects of diamond mining in the Arctic area are discussed.展开更多
The most heavily glacierized tropical range in the world– the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA).In this study,the decline of the Churup glacier(9°28’18"...The most heavily glacierized tropical range in the world– the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA).In this study,the decline of the Churup glacier(9°28’18"S;77°25’02"W)and associated processes were documented employing multi-proxy approach including the analysis of remotely sensed images(1948-2016),the Schmidt hammer rock test and lichenometric dating.It is shown that Churup glacier has lost the vast majority of its estimated LIA extent(1.05±0.1 km^2;45.0×10^6-57.4×10^6 m^3).The rate of glacier retreat is documented to vary in space(SE,SW and NW-facing slopes)and time,with the peak between 1986 and 1995.With an area of 0.045 km^2 in 2016,it is expected that the complete deglaciation of the Churup valley is inevitable in the near future.Recently(post-LIA)exposed bedrock surfaces have shown higher R-values(54.2-66.4,AVG 63.3,STDEV 2.9)compared to pre-LIA exposed surfaces(46.1-59.3,AVG 50.1,STDEV 4.9),confirming the links to the duration of rock weathering.The Lichenometric dating is applied to recently exposed areas and elevations above 4800 m a.s.l.,revealing only limited reliability and agreement with the age of deglaciation estimated from remotely-sensed images in such an environment.展开更多
Entry word 'geo' means the relations between the earty surface layer and its surroundings.The existence and development of humanity are in progress on certain spatial places and duringspecific time series. It...Entry word 'geo' means the relations between the earty surface layer and its surroundings.The existence and development of humanity are in progress on certain spatial places and duringspecific time series. It is not only philosophic truth but also objective reality. People always define theinteraction between human society and natural world as man-land relationship. which contains eitherthe tangible habitat of human being or the intangible bearing got involved in it. So far asgeoenvironment is an enlarged geographic surroundings, from macroscopic cosmos to elementaryparticle without exception. The purpose of thes paper is to expound the relationship for human beingwith its factors affiliated on global surface. The authors firmly believe that humankind possesses threeoverlapping levels of environment on earth enclosure including physical (natural), economic(artificial) and humanistic (ideological) spheres.展开更多
Marine pollution is a serious geoenvironmental problem affecting the Lebanese coast. It mainly affects the coastal zone adjacent to areas of dense population. To detect the sources of pollution along this zone, as wel...Marine pollution is a serious geoenvironmental problem affecting the Lebanese coast. It mainly affects the coastal zone adjacent to areas of dense population. To detect the sources of pollution along this zone, as well as to identify their characteristics, remote sensing data is used. Landsat 8 Operational Land Imager (OLI) satellite images, which have medium spatial resolution, are analyzed using ENVI 5.2 and ArcGIS 10.3.1 geospatial software for the years of 2014 and 2015. Different routines are applied to reveal anomalous features with the goal being to discriminate polluted water in the marine environment. Results showed anomalies in Akkar region. This might be due to the presence of basalts rocks, and geothermal heating, or the pollution of Oustowan river that flows into the sea. The results also showed that during the dry season, there is low movement of water causing a least extension of the anomalies. In contrary, during the wet season, rivers had an intense flow into the sea which caused an intense water movement and wide extension of anomalies on the coast. Permanently polluted coastal sites are evident in Tripoli, Kalamoun, Chekka, Batroun, Amchit, Jbeil, Jounieh, Nahr Beirut and Ouzai with the most presumed polluted months being in 2014 during April and November and in 2015 in April. The least extended pollution is during July 2014 and 2015. The length and width of each anomaly at each site shows that during the year of 2015;most of the anomalies are larger than in 2014.展开更多
基金funded by the Petroleum Technology Development Fund(PTDF),Nigeria.(Award No.:PTDF/ED/OSS/PHD/NOA/1714/20).
文摘Hydrocarbon contamination from oil spills presents geoenvironmental and geoengineering challenges,notably in Eleme,Nigeria.This study integrates electrical resistivity tomography(ERT),soil total petroleum hydrocarbon(TPH)analysis,and geotechnical testing for treated spill site monitoring and characterization over six months.Four 100 m ERT lines,L1 to L4,with spacings at 1.5 m,3 m,6 m,9 m,12 m,and 15 m,were established for the first and second sampling phases.Twenty-one soil samples,12 TPH,and 9 mechanical analyses,were obtained from 5 boreholes,BH1 to BH4,for the study site and the BH5 control site across the phases at 0.5 m,3.0 m,and 5.0 m depths along ERT lines.ERT results reveal resistivity reductions averaging 18%in shallow zones of active degradation,correlating with an average 41%TPH-decrease.Specific gravity averaged 2.49 in the spill soils,compared to 2.58 in control samples,reflecting hydrocarbon-induced density reductions of 3.5%.Particle size showed spill soils contained>50%fines,increasing water retention and reducing permeability by 30%.Consolidation tests highlighted increased compressibility,with settlements of 1.89 mm in spill soils versus 1.01 mm in control samples,indicating a 47%increase in settlement from hydrocarbon reduction.Correlation analysis shows slower consolidation at BH3(−0.62 Cv)with moderate settlement increase(0.25),while BH4 exhibits much higher compressibility(0.95)but minimal Cv impact(0.23),indicating increased structural weakness with higher residual TPH.Spill degradation reduced TPH by 19%-64%in shallow zones,with persistent contamination at deeper layers exceeding the regulatory limits,emphasising the need for ongoing monitoring and targeted remediation for long-term stability and sustainability.
文摘This work focused on the prediction modeling of Cerrado occurrences in the Atlantic Rainforest predominance in the São Paulo Metropolitan Region (SPMR), the fourth largest urban area, in the city of Guarulhos, southeastern Brazil. The methodology was based on the selection of records of occurrence of Cerrado in georeferenced databases, thematic maps of geoenvironmental layers, and modeling of the distribution of species through the MaxEnt tool. Besides that, field research confirmed the presence or not of the species in the areas with a high probability of occurrence of Cerrado (≥0.7). As a result, the model observed a great capacity for the prediction of the occurrence of Cerrado in Ecotonal and anthropic regions (AUC = 0.82), revealing important hotspots such as relics from the past or Cerrado enclaves of high biodiversity. The work also points priority areas for the conservation and preservation of this increasingly endangered biome.
文摘The north-south trending Kullu valley between Rohtang in the north and Hansu in the south is a wide and open valley filled with Quaternary sediments along the main eourse of the Beas River. The valley in the middle is drained by the Beas River and numerous tributaries join it laterally. The tributary ehannels have deposited large alluvial fans at their mouths whieh form three distinct levels. The Beas River has deposited alluvial terraees, whieh are very distinct towards the lower reaehes and form three to four levels. The upper slopes and high altitudinal areas are eovered with periglaeial and glaeial deposits. The terraee, fan and hill slopes have provided an ideal geoenvironment for human aetivities inehiding agrieulture, hortieulture, dense settlements and other eivil establishments. The Kulhi Valley is prone to various natural hazards, flash floods and eloudbursts that are very eommon in this valley due to its peeuliar geomorphie eonclifton, high relief of peripheral ridges and impact of monsoon winds. The studies carried out so far indicate that the losses caused by these phenomena both in terms of life and property are mainly due to unwise human interaction with the geoenvironment of the area. The paper gives an overview of the geoenvironmental status of the Kulhi Valley and suggests the necessity of undertaking further detailed studies ineluding resouree mapping for balaneed development of the area.
文摘This study is conducted to evaluate the ongoing geoenvironmental impacts of Brahmaputra-Jamuna (BJ) River around the Jamuna Bridge (JB) site which was modified prior to the construction of Jamuna Bridge in 1996. Remote sensing and GIS techniques are adopted to evaluate the temporal and spatial geohazards. This study shows that the intensity of channel shifting has been increased due to regulation of river width at Sira-jganj–Bhuiyapur section from 11 km to 4.8 km. Planform analysis shows that the major channel has been stressed to migrate (315 m/year) eastwards. The phenomena of channel changes are predicted to be the con-sequences of interaction of water flow, sedimentation and channel corridor. The erosion and deposition have complicated variations over time and space due to the abrupt changes of flow and sedimentation around the regulated section. Due to width reduction, the bridge site in the braided system acts as sluice gate which can not accommodate the entire flow to release downstream properly. The helical flow developed with the inter-action of guide bund creates local scours and helps to shift the river bank eastward.
文摘Expansive soils are problematic due to the performances of their clay mineral constituent, which makes them exhibit the shrink-swell characteristics. The shrink-swell behaviours make expansive soils inappropriate for direct engineering application in their natural form. In an attempt to make them more feasible for construction purposes, numerous materials and techniques have been used to stabilise the soil. In this study, the additives and techniques applied for stabilising expansive soils will be focused on,with respect to their efficiency in improving the engineering properties of the soils. Then we discussed the microstructural interaction, chemical process, economic implication, nanotechnology application, as well as waste reuse and sustainability. Some issues regarding the effective application of the emerging trends in expansive soil stabilisation were presented with three categories, namely geoenvironmental,standardisation and optimisation issues. Techniques like predictive modelling and exploring methods such as reliability-based design optimisation, response surface methodology, dimensional analysis, and artificial intelligence technology were also proposed in order to ensure that expansive soil stabilisation is efficient.
文摘Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the placers, as well as the poor assimilative capacity of the natural systems can result in serious environmental impacts in the area. The primary geochemical processes in the diamond-bearing area are affected by the occurrence of permafrost and relict ice, the lengthy duration of ice cover in water bodies, and the widespread development of cryogenic processes. This promotes physical migration of contaminants, cryogenic metamorphization of waters, and long-term accumulation of organic contaminants in low-temperature, reduction and sedimentation barriers. In this paper, some environmental and geochemical effects of diamond mining in the Arctic area are discussed.
基金the Ministry of Education, Youth and Sports of the Czech Republic within the framework of the National Sustainability Programme Ⅰ(NPU Ⅰ), Grant No. LO1415
文摘The most heavily glacierized tropical range in the world– the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA).In this study,the decline of the Churup glacier(9°28’18"S;77°25’02"W)and associated processes were documented employing multi-proxy approach including the analysis of remotely sensed images(1948-2016),the Schmidt hammer rock test and lichenometric dating.It is shown that Churup glacier has lost the vast majority of its estimated LIA extent(1.05±0.1 km^2;45.0×10^6-57.4×10^6 m^3).The rate of glacier retreat is documented to vary in space(SE,SW and NW-facing slopes)and time,with the peak between 1986 and 1995.With an area of 0.045 km^2 in 2016,it is expected that the complete deglaciation of the Churup valley is inevitable in the near future.Recently(post-LIA)exposed bedrock surfaces have shown higher R-values(54.2-66.4,AVG 63.3,STDEV 2.9)compared to pre-LIA exposed surfaces(46.1-59.3,AVG 50.1,STDEV 4.9),confirming the links to the duration of rock weathering.The Lichenometric dating is applied to recently exposed areas and elevations above 4800 m a.s.l.,revealing only limited reliability and agreement with the age of deglaciation estimated from remotely-sensed images in such an environment.
文摘Entry word 'geo' means the relations between the earty surface layer and its surroundings.The existence and development of humanity are in progress on certain spatial places and duringspecific time series. It is not only philosophic truth but also objective reality. People always define theinteraction between human society and natural world as man-land relationship. which contains eitherthe tangible habitat of human being or the intangible bearing got involved in it. So far asgeoenvironment is an enlarged geographic surroundings, from macroscopic cosmos to elementaryparticle without exception. The purpose of thes paper is to expound the relationship for human beingwith its factors affiliated on global surface. The authors firmly believe that humankind possesses threeoverlapping levels of environment on earth enclosure including physical (natural), economic(artificial) and humanistic (ideological) spheres.
文摘Marine pollution is a serious geoenvironmental problem affecting the Lebanese coast. It mainly affects the coastal zone adjacent to areas of dense population. To detect the sources of pollution along this zone, as well as to identify their characteristics, remote sensing data is used. Landsat 8 Operational Land Imager (OLI) satellite images, which have medium spatial resolution, are analyzed using ENVI 5.2 and ArcGIS 10.3.1 geospatial software for the years of 2014 and 2015. Different routines are applied to reveal anomalous features with the goal being to discriminate polluted water in the marine environment. Results showed anomalies in Akkar region. This might be due to the presence of basalts rocks, and geothermal heating, or the pollution of Oustowan river that flows into the sea. The results also showed that during the dry season, there is low movement of water causing a least extension of the anomalies. In contrary, during the wet season, rivers had an intense flow into the sea which caused an intense water movement and wide extension of anomalies on the coast. Permanently polluted coastal sites are evident in Tripoli, Kalamoun, Chekka, Batroun, Amchit, Jbeil, Jounieh, Nahr Beirut and Ouzai with the most presumed polluted months being in 2014 during April and November and in 2015 in April. The least extended pollution is during July 2014 and 2015. The length and width of each anomaly at each site shows that during the year of 2015;most of the anomalies are larger than in 2014.
