Several pit lakes exist in the Raipur area due to lime stone mining. The water of pit lakes is used for bathing, washing and irrigation purposes. They are found to be contaminated with toxicants i.e. fluoride, su...Several pit lakes exist in the Raipur area due to lime stone mining. The water of pit lakes is used for bathing, washing and irrigation purposes. They are found to be contaminated with toxicants i.e. fluoride, surfactants and microbes far above the recommended limits. In this work, the water quality of 29 pit lakes locates in two districts: Raipur and Baloda Bazar, Chhattisgarh, India are assessed for drinking and irrigation purposes.展开更多
Pit lakes may form in mining voids that extend below groundwater level after mining ceases and many have been found to have elevated metals concentrations and low pH through acidic and metalliferous drainage (AMD). Pi...Pit lakes may form in mining voids that extend below groundwater level after mining ceases and many have been found to have elevated metals concentrations and low pH through acidic and metalliferous drainage (AMD). Pit lakes are often used for recreational activities including swimming, fishing and boating and poor water quality may present health risks to recreational users. Pit lakes also provide the opportunity for additional water resource uses. The Collie Coal Basin in south-western Australia currently has a number of pit lakes with moderate AMD effects which are also used for recreational pursuits. Twelve hundred questionnaires were mailed to selected addresses in the Collie shire with an additional 170 questionnaires to specific interest groups. Participants were asked about the type of activity, frequency and duration and any health symptoms experienced after use of the lakes. Two hundred and fifty questionnaires were returned, which comprised 176 returns from the random sample and 74 from the targeted sample. Three pit lakes with elevated metals concentrations and low pH were used for recreational purposes by 62% of respondents. This was mostly in summer with swimming the most common activity. Of all respondents 52% were concerned about lake water quality and 38% using the lakes reported a variety of symptoms. Recreational use of Collie pit lakes did not represent a health risk for most of the surveyed population due to the low frequency and duration of use, however health risks may be elevated in sensitive users such as children and those consuming seafood from the lakes. Comprehensive water quality monitoring for chemicals and further characterisation of recreational use of pit lakes is warranted to more comprehensively assess the potential health risks to recreational users. Post closure mine plans need to consider potential future community uses combined with assessments of water quality and physical characteristics to reduce the potential for adverse health and safety impacts.展开更多
Predictive geochemical and limnologic modeling of pit lakes is an important aspect of modern mine-site permitting. One of the key assumptions of many predictive pit-lake models is that open-pit high walls and in-pit b...Predictive geochemical and limnologic modeling of pit lakes is an important aspect of modern mine-site permitting. One of the key assumptions of many predictive pit-lake models is that open-pit high walls and in-pit backfill become geochemically unreactive once submerged by the filling pit lake. Existing pit lakes provide useful data to test this assumption. The Sleeper pit lake (northwestern Nevada, USA) is approaching hydrologic equilibrium and contains good-quality water that generally meets regulatory requirements for pit lakes. Despite the overall stable geochemical composition, seasonal trends in the hypolimnion indicate the generation of dissolved metals associated with the ore deposit (e.g., Mn and Zn) and cyclical variations in pH. This study applies mass balance, analysis of subaqueous pyrite oxidation, and trends in solute concentrations to evaluate the potential causes of long-term solute generation in the hypolimnion of the Sleeper pit lake. Three separate conceptual models (subaqueous pyrite oxidation;redox reactions;and diffusion of solutes from a permanently stratified bottom layer) were tested against the high-quality dataset available for the pit lake. Evaluation of the monitoring dataset for the pit lake indicates that the Sleeper pit lake has variable limnologic behavior, wherein the lake is consistently stratified (meromictic) in some years, while it undergoes full mixing (holomixis) in other time periods. Comparison of the data with the three conceptual models illustrates that none of these models can be completely implicated as causing the seasonal geochemical variations in the bottom of the pit lake, but that a combination of the processes is likely partially responsible. Additional data collection including sediment cores and in-situ pore-water analysis would aid in understanding geochemical processes occurring over time.展开更多
Removal of trees and shrubs from hillsides exposes a site to erosion that threatens soil aggregation and stability. The present study aimed at evaluating the performance of five indigenous tree species in rehabilitati...Removal of trees and shrubs from hillsides exposes a site to erosion that threatens soil aggregation and stability. The present study aimed at evaluating the performance of five indigenous tree species in rehabilitation of degraded hillsides of Kuriftu Lake Catchment and the role of water harvesting structures. Adaptability varied by tree species and water harvesting structures significantly augmented seedling es-tablishment for some tree species. Height ofAcacia abyssinicaplanted on steeper slopes （18%-27%） without infiltration pits was lower than for conspecifics planted with infiltration pits.Dodonaea angustifolia wasproved to be best adapted to the siteand showed no need for water harvesting regardless of planting position across the degraded hillside. Planting ofAcacia seyalshould be restricted to gentler slopes （0-17%） with infiltration pits： tree height declined significantly on steep slopes without infiltration pits.Olea africanaperformed better on gentle slopes with pits but also grew well on steeper slopes with pits.Euclea schim-periwasproved to be least effective of the species evaluated in this study.展开更多
Jiuzhaigou Conservation is a typical karst region with scenic tufa constructive landscape. With observation in situ and optical microscope as well as scanning electronic microscope, a series minor and micro biokar...Jiuzhaigou Conservation is a typical karst region with scenic tufa constructive landscape. With observation in situ and optical microscope as well as scanning electronic microscope, a series minor and micro biokarst solution features and related agents were identified and described related to local environmental condition, and also the bioeffect on karst deposition in formation of the local tufa dammed lakes were elucidated and discussed.It is shown in the cycle model proposed in the paper that many organisms (algae,mosses,and bushes etc.) with various effects (assimilation,interception,encrustation,trapping and binding etc.)on tufa deposition play an important role throughout the compound cycle process of the tufa dam gradation,i.e.the formation of the tufa dammed lakes in the stream channels which are character of local karst landscape.展开更多
文摘Several pit lakes exist in the Raipur area due to lime stone mining. The water of pit lakes is used for bathing, washing and irrigation purposes. They are found to be contaminated with toxicants i.e. fluoride, surfactants and microbes far above the recommended limits. In this work, the water quality of 29 pit lakes locates in two districts: Raipur and Baloda Bazar, Chhattisgarh, India are assessed for drinking and irrigation purposes.
文摘Pit lakes may form in mining voids that extend below groundwater level after mining ceases and many have been found to have elevated metals concentrations and low pH through acidic and metalliferous drainage (AMD). Pit lakes are often used for recreational activities including swimming, fishing and boating and poor water quality may present health risks to recreational users. Pit lakes also provide the opportunity for additional water resource uses. The Collie Coal Basin in south-western Australia currently has a number of pit lakes with moderate AMD effects which are also used for recreational pursuits. Twelve hundred questionnaires were mailed to selected addresses in the Collie shire with an additional 170 questionnaires to specific interest groups. Participants were asked about the type of activity, frequency and duration and any health symptoms experienced after use of the lakes. Two hundred and fifty questionnaires were returned, which comprised 176 returns from the random sample and 74 from the targeted sample. Three pit lakes with elevated metals concentrations and low pH were used for recreational purposes by 62% of respondents. This was mostly in summer with swimming the most common activity. Of all respondents 52% were concerned about lake water quality and 38% using the lakes reported a variety of symptoms. Recreational use of Collie pit lakes did not represent a health risk for most of the surveyed population due to the low frequency and duration of use, however health risks may be elevated in sensitive users such as children and those consuming seafood from the lakes. Comprehensive water quality monitoring for chemicals and further characterisation of recreational use of pit lakes is warranted to more comprehensively assess the potential health risks to recreational users. Post closure mine plans need to consider potential future community uses combined with assessments of water quality and physical characteristics to reduce the potential for adverse health and safety impacts.
文摘Predictive geochemical and limnologic modeling of pit lakes is an important aspect of modern mine-site permitting. One of the key assumptions of many predictive pit-lake models is that open-pit high walls and in-pit backfill become geochemically unreactive once submerged by the filling pit lake. Existing pit lakes provide useful data to test this assumption. The Sleeper pit lake (northwestern Nevada, USA) is approaching hydrologic equilibrium and contains good-quality water that generally meets regulatory requirements for pit lakes. Despite the overall stable geochemical composition, seasonal trends in the hypolimnion indicate the generation of dissolved metals associated with the ore deposit (e.g., Mn and Zn) and cyclical variations in pH. This study applies mass balance, analysis of subaqueous pyrite oxidation, and trends in solute concentrations to evaluate the potential causes of long-term solute generation in the hypolimnion of the Sleeper pit lake. Three separate conceptual models (subaqueous pyrite oxidation;redox reactions;and diffusion of solutes from a permanently stratified bottom layer) were tested against the high-quality dataset available for the pit lake. Evaluation of the monitoring dataset for the pit lake indicates that the Sleeper pit lake has variable limnologic behavior, wherein the lake is consistently stratified (meromictic) in some years, while it undergoes full mixing (holomixis) in other time periods. Comparison of the data with the three conceptual models illustrates that none of these models can be completely implicated as causing the seasonal geochemical variations in the bottom of the pit lake, but that a combination of the processes is likely partially responsible. Additional data collection including sediment cores and in-situ pore-water analysis would aid in understanding geochemical processes occurring over time.
文摘Removal of trees and shrubs from hillsides exposes a site to erosion that threatens soil aggregation and stability. The present study aimed at evaluating the performance of five indigenous tree species in rehabilitation of degraded hillsides of Kuriftu Lake Catchment and the role of water harvesting structures. Adaptability varied by tree species and water harvesting structures significantly augmented seedling es-tablishment for some tree species. Height ofAcacia abyssinicaplanted on steeper slopes （18%-27%） without infiltration pits was lower than for conspecifics planted with infiltration pits.Dodonaea angustifolia wasproved to be best adapted to the siteand showed no need for water harvesting regardless of planting position across the degraded hillside. Planting ofAcacia seyalshould be restricted to gentler slopes （0-17%） with infiltration pits： tree height declined significantly on steep slopes without infiltration pits.Olea africanaperformed better on gentle slopes with pits but also grew well on steeper slopes with pits.Euclea schim-periwasproved to be least effective of the species evaluated in this study.
文摘Jiuzhaigou Conservation is a typical karst region with scenic tufa constructive landscape. With observation in situ and optical microscope as well as scanning electronic microscope, a series minor and micro biokarst solution features and related agents were identified and described related to local environmental condition, and also the bioeffect on karst deposition in formation of the local tufa dammed lakes were elucidated and discussed.It is shown in the cycle model proposed in the paper that many organisms (algae,mosses,and bushes etc.) with various effects (assimilation,interception,encrustation,trapping and binding etc.)on tufa deposition play an important role throughout the compound cycle process of the tufa dam gradation,i.e.the formation of the tufa dammed lakes in the stream channels which are character of local karst landscape.
