Dr.Navendu Chaudhary - Academia.edu (original) (raw)
Papers by Dr.Navendu Chaudhary
Review of the manuscript ' Cloud-based geospatial services for building capacity and safeguarding... more Review of the manuscript ' Cloud-based geospatial services for building capacity and safeguarding heritage in climatically marginal landscapes' by Lim et al. submitted to Qeios. Focus of the paper: changing landscapes in the context of climate change crisis. Climate-environmental transition was evaluated with a case of two regions: Yukon-Kuskokwim Delta in Alaska, USA and Mauritania. Abstract is well written and clearly describes the undertaken study. Structure: The article is well organized with structured sections. The structure of the manuscript conforms to the journal standards and discipline norm and includes 4 Sections. Section 2 "Automatic Workflows for Remote Communities" is subdivided into the minor subsections and paragraphs and well describes the workflow with examples of scripts. The numeration of the sections is correct and consecutive. Logic: The clarity of the text logic and organization of the paper is sufficient. It demonstrates the consistent interpretation of the results with detailed explanations and comments. A comparison of the results with those in previous studies is presented.
International Journal of Medical Engineering and Informatics, 2022
International Journal of Computing and Digital Systems, Jan 9, 2022
In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formu... more In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formulas of the chemical compounds. While digitizing the handwritten or printed contents related to inorganic chemistry, firstly it has to recognize handwritten inorganic chemical formulas (HICF). The HICF has represented by using alphabets and numbers, this alphabet or number is termed as Inorganic Symbols (IS). Therefore, to recognize HICF; the inorganic symbols have to be reorganized. Here in this paper, we had developed a model to recognize HICF. The developed model has based on the classification of inorganic symbols (IS). This proposed model does the classification based on geometric shapes, which are part of the IS. The classification of IS has done in three classes based on the geometric shapes used to formulate the IS. After classification, this model identifies the individual IS with the help of feature descriptor and Support Vector Machine (SVM). In this paper, each class has it's trained SVM to identify individual IS from the respective class. Once each individual IS has identified then it has put together to represent in the inorganic chemical formula. The result shows that the recognition percentage of each SVM is nearly equal to 97%. The system accepts scanned images of HICF as an input and delivers recognized HICF in text format as an output.
Urban Water Journal, 2022
International Journal of Computing and Digital Systems, 2022
In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formu... more In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formulas of the chemical compounds. While digitizing the handwritten or printed contents related to inorganic chemistry, firstly it has to recognize handwritten inorganic chemical formulas (HICF). The HICF has represented by using alphabets and numbers, this alphabet or number is termed as Inorganic Symbols (IS). Therefore, to recognize HICF; the inorganic symbols have to be reorganized. Here in this paper, we had developed a model to recognize HICF. The developed model has based on the classification of inorganic symbols (IS). This proposed model does the classification based on geometric shapes, which are part of the IS. The classification of IS has done in three classes based on the geometric shapes used to formulate the IS. After classification, this model identifies the individual IS with the help of feature descriptor and Support Vector Machine (SVM). In this paper, each class has it's trained SVM to identify individual IS from the respective class. Once each individual IS has identified then it has put together to represent in the inorganic chemical formula. The result shows that the recognition percentage of each SVM is nearly equal to 97%. The system accepts scanned images of HICF as an input and delivers recognized HICF in text format as an output.
Indian Journal of Public Health Research & Development, 2017
2017 Second International Conference on Electrical, Computer and Communication Technologies (ICECCT), 2017
The basic components of chemical expressions and its corresponding reactions are chemical symbols... more The basic components of chemical expressions and its corresponding reactions are chemical symbols and structures. To recognize a handwritten or printed chemical expression, proper identification of the chemical symbols and structures are important. This paper has reviewed the existing algorithms and models used for identifying the organic chemical structures. The objective of this paper is to find out chemical structures and symbols which are in a handwritten format and proposed model is based on fuzzy image segmentation technique.
Urban water issues impacting sustainable development can be analyzed, modeled, and mapped through... more Urban water issues impacting sustainable development can be analyzed, modeled, and mapped through cutting-edge geospatial technologies; however, the water sector in developing countries suffers various spatial data-related problems such as limited coverage, unreliable data, limited coordination, and sharing. Available spatial data is limited to the aggregate level (i.e., National, State, and District level) and lacks details to make informed policy decisions and allocations. Despite significant advancements in geospatial technologies, its application and integration at the policy and decision-making level are seldom. The current research provides a unique, holistic Geospatial Framework to measure and monitor water security through geospatial technologies. The study demonstrates the application of the proposed Geospatial Framework from technical and institutional perspectives in water-stressed zones in Pune city showing where and how to solve problems and where proposed actions can h...
Water Supply, 2021
The water supply system in the city of Pune is affected due to the fast and chaotic development i... more The water supply system in the city of Pune is affected due to the fast and chaotic development in and around the city. The quantity of per capita water supply and hours of supply per day varies substantially across the city. Some central parts of the city benefit from a large availability of water as compared to peripheral areas. This research employed Ordinary Least Squares (OLS) Regression, Geographically Weighted Regression (GWR), and the new version of GWR termed Multi-scale Geographically Weighted Regression (MGWR) models to better understand the factors behind observed spatial patterns of water supply distribution and to predict water supply in newly merged and proposed villages in the Pune city's periphery. Results showed statistical significance of slope; distance from service reservoirs; and water supply hour. MGWR and GWR models improved our results (adjusted R2: 0.916 and 0.710 respectively) significantly over those of the OLS model (adjusted R2: 0.252) and proved ho...
International Journal of Recent Technology and Engineering (IJRTE), 2019
Sustainable development requires judicious use of resources which can cater for present need and ... more Sustainable development requires judicious use of resources which can cater for present need and also makes provision for the future. Geospatial technology operates at a regional level as well as micro level by providing a framework for data visualization and analysis which is crucial to the decision making process. Such a platform provides tools that help decision makers analyze complex situations and complete the task with efficiency. Research shows that Geospatial thinking is critical to survive and operate in today’s digitized world. Research has also shown that education in Geospatial technology will be crucial to make workforce competent across all sectors of the economy and it will be particularly necessary for achieving sustainable development goals. Geospatial education in India is lagging behind the rest of the world due to the specific constraints of the University structure in running Interdisciplinary subject. Geography education largely restricts to bachelor degree wit...
Reconsidering the Impact of Climate Change on Global Water Supply, Use, and Management
Coastal Maharashtra is in transition. Growing coastal tourism and allied developmental activities... more Coastal Maharashtra is in transition. Growing coastal tourism and allied developmental activities along southern Maharashtra coast needs integration of various stakeholders to address the various issues and concerns. Integrated Coastal Zone Management (ICZM), which can cater to the needs of people while preserving the environment is thus need of the hour. The effects on natural resources, including water, will change the socioeconomic as well as the cultural fabric of coastal communities. This chapter explores a holistic approach to the developmental issues and the impact of climate change on the coastal region with specific cases of villages of Devbag and Tarkarli, coastal Maharashtra, India. It explores both physical and socioeconomic landscapes with special attention given to water resources in the context of changing dynamics of coastal communities and coastal tourism. The chapter discusses the issues and concerns of villages of Devbag and Tarkarli and proposes solutions for a s...
GIScience & Remote Sensing, 2008
The purpose of this research is to evaluate the utility of image segmentation and object-oriented... more The purpose of this research is to evaluate the utility of image segmentation and object-oriented processing for land cover classification in Ohio. Eight level-II land cover categories were classified using a region-growing segmentation algorithm and object-oriented fuzzy classification membership functions. The overall accuracy of the classification was 93.6%. Producer accuracies ranged from 89.63% for urban/recreational grasses to 98.01% for water. User accuracies ranged from 90.83% for deciduous forest to 99.49% for water. The high classification accuracies are primarily due to: (1) the use of multiple scales in the segmentation process for classification of small to large phenomena at the appropriate scale; (2) integration of textural, contextual, shape, and spectral information in the classification process; and (3) use of multi-temporal data to capture both leaf-on and leaf-off properties of land cover categories.
Geoinformatics 2008 and Joint Conference on GIS and Built Environment: Classification of Remote Sensing Images, 2008
The purpose of this research was to evaluate six classifiers applied to Landsat-7 data for accura... more The purpose of this research was to evaluate six classifiers applied to Landsat-7 data for accuracy of Level II land-cover categories in Ohio. These methods consist of (1) USGS National Land Cover Data; (2) the spectral angle mapper; (3) the maximum likelihood classifier; (4) the maximum likelihood classifier with texture analysis; (5) a recently introduced hybrid artificial neural network; (6)
Water Research, 2004
The toxic effects of heavy metals, zinc and copper, in unary and binary solutions were studied us... more The toxic effects of heavy metals, zinc and copper, in unary and binary solutions were studied using the Microtox s acute toxicity test which relies upon the attenuation of light intensity emitted by Vibrio fischeri. The toxic effect G (ratio of the light intensity lost at time t to the light intensity remaining at time t) of zinc could be related to its concentration [X] by a two-parameter equation G ¼ að1 À expðÀb½X ÞÞ, where parameter a was a function of time and b equal to 0.88 L/mg. The toxic effect of zinc asymptotically approached a maximum with respect of to concentration at all times. The toxic effect of copper was fundamentally different from that of zinc, and increased exponentially with concentration without any limiting maximum value. It could also be described by a two-parameter equation, however, the equation had the form G ¼ a expðb½X Þ, where parameter a was a constant and b a function of time. The different functional dependencies (of the toxic effect on the metal concentration) of zinc and copper indicate that different toxicity/inhibition mechanisms were possibly responsible for the attenuation of light intensity for the two metals. The toxic effects of binary mixtures were substantially higher than those expected on the basis of additivity of individual metals. No simple correlations were obtained that could relate the toxic effect of binary mixture to those of individual metals. A better understanding of metal-microbe interactions is needed for achieving predictive capability for toxic effect of mixtures.
Environmental Toxicology and Chemistry, 2001
Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental con... more Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the heavy metals at concentrations below EC100. The 7-d EC50 values obtained from the difference between the dissolved metal concentrations for the control tubes (tubes not containing copper or zinc) and tubes containing metals were found to be 10.5 mg/L for copper and 16.5 mg/L for zinc. Measurements of the turbidity and pH, bacterial population estimations by means of a most-probable number technique, and metal recovery in the sulfide precipitate were found to have only a limited applicability in these determinations.
Environmental Toxicology, 2002
Acid mine drainage (AMD) containing high concentrations of sulfate and heavy metal ions can be tr... more Acid mine drainage (AMD) containing high concentrations of sulfate and heavy metal ions can be treated by biological sulfate reduction. It has been reported that the effect of heavy metals on sulfate-reducing bacteria (SRB) can be stimulatory at lower concentrations and toxic/inhibitory at higher concentrations. The quantification of the toxic/inhibitory effect of dissolved heavy metals is critical for the design and operation of an effective AMD bioremediation process. Serum bottle and batch reactor studies on metal toxicity to SRB indicate that insoluble metal sulfides can inhibit the SRB activity as well. The mechanism of inhibition is postulated to be external to the bacterial cell. The experimental data indicate that the metal sulfides formed due to the reaction between the dissolved metal and biogenic sulfide act as barriers preventing the access of the reactants (sulfate, organic matter) to the necessary enzymes. Scanning electron micrographs of the SRB cultures exposed to copper and zinc provide supporting evidence for this hypothesis. The SRB cultures retained their ability to effect sulfate reduction indicating that the metal sulfides were not lethally toxic to the SRB. This phenomenon of metal sulfide inhibition of the SRB has to be taken into account while designing a sulfate-reducing bioreator, and subsequently an efficient biotreatment strategy for AMD. Any metal sulfide formed in the bioreactor needs to be removed immediately from the system to maintain the efficiency of the process of sulfate reduction.
The purpose of this research was to develop an object oriented approach to land cover analysis an... more The purpose of this research was to develop an object oriented approach to land cover analysis and evaluate this approach along with five other classifiers for accuracy in classifying Level II land-cover categories in Ohio. These methods consist of (1) USGS National Land Cover ...
Water Sustainability eJournal, 2016
India has a long coastline of about 7,500 kilometers, with an exclusive economic zone (EEZ) of 2.... more India has a long coastline of about 7,500 kilometers, with an exclusive economic zone (EEZ) of 2.02 million square kilometers. The state of Maharashtra is located on the western side of the Indian Peninsula. The state has 720 kilometers coastline. Towards the southern end of Maharashtra coastline lies the Sindhudurg coastal district. Situated between latitudes 150 37’ and 16040’ north and longitudes 73019’ and 74018’ east, Sindhudurg district has a coastline of 121 kilometers. Apart from the beautiful pocket sandy beaches, island & inland ports, the coast is also known for built heritage, local culture and Malvani cuisine. The area has rich coastal and marine biodiversity. Ecosystem services are extremely important for the sustenance of livelihood of local people. However, coastal tourism has picked up in a most unplanned manner in last two decades in three coastal districts Deogad, Malvan, Vengurla of Sindhudurg district. The paper starts with the key statements by some of the repu...
Review of the manuscript ' Cloud-based geospatial services for building capacity and safeguarding... more Review of the manuscript ' Cloud-based geospatial services for building capacity and safeguarding heritage in climatically marginal landscapes' by Lim et al. submitted to Qeios. Focus of the paper: changing landscapes in the context of climate change crisis. Climate-environmental transition was evaluated with a case of two regions: Yukon-Kuskokwim Delta in Alaska, USA and Mauritania. Abstract is well written and clearly describes the undertaken study. Structure: The article is well organized with structured sections. The structure of the manuscript conforms to the journal standards and discipline norm and includes 4 Sections. Section 2 "Automatic Workflows for Remote Communities" is subdivided into the minor subsections and paragraphs and well describes the workflow with examples of scripts. The numeration of the sections is correct and consecutive. Logic: The clarity of the text logic and organization of the paper is sufficient. It demonstrates the consistent interpretation of the results with detailed explanations and comments. A comparison of the results with those in previous studies is presented.
International Journal of Medical Engineering and Informatics, 2022
International Journal of Computing and Digital Systems, Jan 9, 2022
In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formu... more In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formulas of the chemical compounds. While digitizing the handwritten or printed contents related to inorganic chemistry, firstly it has to recognize handwritten inorganic chemical formulas (HICF). The HICF has represented by using alphabets and numbers, this alphabet or number is termed as Inorganic Symbols (IS). Therefore, to recognize HICF; the inorganic symbols have to be reorganized. Here in this paper, we had developed a model to recognize HICF. The developed model has based on the classification of inorganic symbols (IS). This proposed model does the classification based on geometric shapes, which are part of the IS. The classification of IS has done in three classes based on the geometric shapes used to formulate the IS. After classification, this model identifies the individual IS with the help of feature descriptor and Support Vector Machine (SVM). In this paper, each class has it's trained SVM to identify individual IS from the respective class. Once each individual IS has identified then it has put together to represent in the inorganic chemical formula. The result shows that the recognition percentage of each SVM is nearly equal to 97%. The system accepts scanned images of HICF as an input and delivers recognized HICF in text format as an output.
Urban Water Journal, 2022
International Journal of Computing and Digital Systems, 2022
In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formu... more In inorganic chemistry, the chemical reactions are mostly represented by Inorganic chemical formulas of the chemical compounds. While digitizing the handwritten or printed contents related to inorganic chemistry, firstly it has to recognize handwritten inorganic chemical formulas (HICF). The HICF has represented by using alphabets and numbers, this alphabet or number is termed as Inorganic Symbols (IS). Therefore, to recognize HICF; the inorganic symbols have to be reorganized. Here in this paper, we had developed a model to recognize HICF. The developed model has based on the classification of inorganic symbols (IS). This proposed model does the classification based on geometric shapes, which are part of the IS. The classification of IS has done in three classes based on the geometric shapes used to formulate the IS. After classification, this model identifies the individual IS with the help of feature descriptor and Support Vector Machine (SVM). In this paper, each class has it's trained SVM to identify individual IS from the respective class. Once each individual IS has identified then it has put together to represent in the inorganic chemical formula. The result shows that the recognition percentage of each SVM is nearly equal to 97%. The system accepts scanned images of HICF as an input and delivers recognized HICF in text format as an output.
Indian Journal of Public Health Research & Development, 2017
2017 Second International Conference on Electrical, Computer and Communication Technologies (ICECCT), 2017
The basic components of chemical expressions and its corresponding reactions are chemical symbols... more The basic components of chemical expressions and its corresponding reactions are chemical symbols and structures. To recognize a handwritten or printed chemical expression, proper identification of the chemical symbols and structures are important. This paper has reviewed the existing algorithms and models used for identifying the organic chemical structures. The objective of this paper is to find out chemical structures and symbols which are in a handwritten format and proposed model is based on fuzzy image segmentation technique.
Urban water issues impacting sustainable development can be analyzed, modeled, and mapped through... more Urban water issues impacting sustainable development can be analyzed, modeled, and mapped through cutting-edge geospatial technologies; however, the water sector in developing countries suffers various spatial data-related problems such as limited coverage, unreliable data, limited coordination, and sharing. Available spatial data is limited to the aggregate level (i.e., National, State, and District level) and lacks details to make informed policy decisions and allocations. Despite significant advancements in geospatial technologies, its application and integration at the policy and decision-making level are seldom. The current research provides a unique, holistic Geospatial Framework to measure and monitor water security through geospatial technologies. The study demonstrates the application of the proposed Geospatial Framework from technical and institutional perspectives in water-stressed zones in Pune city showing where and how to solve problems and where proposed actions can h...
Water Supply, 2021
The water supply system in the city of Pune is affected due to the fast and chaotic development i... more The water supply system in the city of Pune is affected due to the fast and chaotic development in and around the city. The quantity of per capita water supply and hours of supply per day varies substantially across the city. Some central parts of the city benefit from a large availability of water as compared to peripheral areas. This research employed Ordinary Least Squares (OLS) Regression, Geographically Weighted Regression (GWR), and the new version of GWR termed Multi-scale Geographically Weighted Regression (MGWR) models to better understand the factors behind observed spatial patterns of water supply distribution and to predict water supply in newly merged and proposed villages in the Pune city's periphery. Results showed statistical significance of slope; distance from service reservoirs; and water supply hour. MGWR and GWR models improved our results (adjusted R2: 0.916 and 0.710 respectively) significantly over those of the OLS model (adjusted R2: 0.252) and proved ho...
International Journal of Recent Technology and Engineering (IJRTE), 2019
Sustainable development requires judicious use of resources which can cater for present need and ... more Sustainable development requires judicious use of resources which can cater for present need and also makes provision for the future. Geospatial technology operates at a regional level as well as micro level by providing a framework for data visualization and analysis which is crucial to the decision making process. Such a platform provides tools that help decision makers analyze complex situations and complete the task with efficiency. Research shows that Geospatial thinking is critical to survive and operate in today’s digitized world. Research has also shown that education in Geospatial technology will be crucial to make workforce competent across all sectors of the economy and it will be particularly necessary for achieving sustainable development goals. Geospatial education in India is lagging behind the rest of the world due to the specific constraints of the University structure in running Interdisciplinary subject. Geography education largely restricts to bachelor degree wit...
Reconsidering the Impact of Climate Change on Global Water Supply, Use, and Management
Coastal Maharashtra is in transition. Growing coastal tourism and allied developmental activities... more Coastal Maharashtra is in transition. Growing coastal tourism and allied developmental activities along southern Maharashtra coast needs integration of various stakeholders to address the various issues and concerns. Integrated Coastal Zone Management (ICZM), which can cater to the needs of people while preserving the environment is thus need of the hour. The effects on natural resources, including water, will change the socioeconomic as well as the cultural fabric of coastal communities. This chapter explores a holistic approach to the developmental issues and the impact of climate change on the coastal region with specific cases of villages of Devbag and Tarkarli, coastal Maharashtra, India. It explores both physical and socioeconomic landscapes with special attention given to water resources in the context of changing dynamics of coastal communities and coastal tourism. The chapter discusses the issues and concerns of villages of Devbag and Tarkarli and proposes solutions for a s...
GIScience & Remote Sensing, 2008
The purpose of this research is to evaluate the utility of image segmentation and object-oriented... more The purpose of this research is to evaluate the utility of image segmentation and object-oriented processing for land cover classification in Ohio. Eight level-II land cover categories were classified using a region-growing segmentation algorithm and object-oriented fuzzy classification membership functions. The overall accuracy of the classification was 93.6%. Producer accuracies ranged from 89.63% for urban/recreational grasses to 98.01% for water. User accuracies ranged from 90.83% for deciduous forest to 99.49% for water. The high classification accuracies are primarily due to: (1) the use of multiple scales in the segmentation process for classification of small to large phenomena at the appropriate scale; (2) integration of textural, contextual, shape, and spectral information in the classification process; and (3) use of multi-temporal data to capture both leaf-on and leaf-off properties of land cover categories.
Geoinformatics 2008 and Joint Conference on GIS and Built Environment: Classification of Remote Sensing Images, 2008
The purpose of this research was to evaluate six classifiers applied to Landsat-7 data for accura... more The purpose of this research was to evaluate six classifiers applied to Landsat-7 data for accuracy of Level II land-cover categories in Ohio. These methods consist of (1) USGS National Land Cover Data; (2) the spectral angle mapper; (3) the maximum likelihood classifier; (4) the maximum likelihood classifier with texture analysis; (5) a recently introduced hybrid artificial neural network; (6)
Water Research, 2004
The toxic effects of heavy metals, zinc and copper, in unary and binary solutions were studied us... more The toxic effects of heavy metals, zinc and copper, in unary and binary solutions were studied using the Microtox s acute toxicity test which relies upon the attenuation of light intensity emitted by Vibrio fischeri. The toxic effect G (ratio of the light intensity lost at time t to the light intensity remaining at time t) of zinc could be related to its concentration [X] by a two-parameter equation G ¼ að1 À expðÀb½X ÞÞ, where parameter a was a function of time and b equal to 0.88 L/mg. The toxic effect of zinc asymptotically approached a maximum with respect of to concentration at all times. The toxic effect of copper was fundamentally different from that of zinc, and increased exponentially with concentration without any limiting maximum value. It could also be described by a two-parameter equation, however, the equation had the form G ¼ a expðb½X Þ, where parameter a was a constant and b a function of time. The different functional dependencies (of the toxic effect on the metal concentration) of zinc and copper indicate that different toxicity/inhibition mechanisms were possibly responsible for the attenuation of light intensity for the two metals. The toxic effects of binary mixtures were substantially higher than those expected on the basis of additivity of individual metals. No simple correlations were obtained that could relate the toxic effect of binary mixture to those of individual metals. A better understanding of metal-microbe interactions is needed for achieving predictive capability for toxic effect of mixtures.
Environmental Toxicology and Chemistry, 2001
Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental con... more Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the heavy metals at concentrations below EC100. The 7-d EC50 values obtained from the difference between the dissolved metal concentrations for the control tubes (tubes not containing copper or zinc) and tubes containing metals were found to be 10.5 mg/L for copper and 16.5 mg/L for zinc. Measurements of the turbidity and pH, bacterial population estimations by means of a most-probable number technique, and metal recovery in the sulfide precipitate were found to have only a limited applicability in these determinations.
Environmental Toxicology, 2002
Acid mine drainage (AMD) containing high concentrations of sulfate and heavy metal ions can be tr... more Acid mine drainage (AMD) containing high concentrations of sulfate and heavy metal ions can be treated by biological sulfate reduction. It has been reported that the effect of heavy metals on sulfate-reducing bacteria (SRB) can be stimulatory at lower concentrations and toxic/inhibitory at higher concentrations. The quantification of the toxic/inhibitory effect of dissolved heavy metals is critical for the design and operation of an effective AMD bioremediation process. Serum bottle and batch reactor studies on metal toxicity to SRB indicate that insoluble metal sulfides can inhibit the SRB activity as well. The mechanism of inhibition is postulated to be external to the bacterial cell. The experimental data indicate that the metal sulfides formed due to the reaction between the dissolved metal and biogenic sulfide act as barriers preventing the access of the reactants (sulfate, organic matter) to the necessary enzymes. Scanning electron micrographs of the SRB cultures exposed to copper and zinc provide supporting evidence for this hypothesis. The SRB cultures retained their ability to effect sulfate reduction indicating that the metal sulfides were not lethally toxic to the SRB. This phenomenon of metal sulfide inhibition of the SRB has to be taken into account while designing a sulfate-reducing bioreator, and subsequently an efficient biotreatment strategy for AMD. Any metal sulfide formed in the bioreactor needs to be removed immediately from the system to maintain the efficiency of the process of sulfate reduction.
The purpose of this research was to develop an object oriented approach to land cover analysis an... more The purpose of this research was to develop an object oriented approach to land cover analysis and evaluate this approach along with five other classifiers for accuracy in classifying Level II land-cover categories in Ohio. These methods consist of (1) USGS National Land Cover ...
Water Sustainability eJournal, 2016
India has a long coastline of about 7,500 kilometers, with an exclusive economic zone (EEZ) of 2.... more India has a long coastline of about 7,500 kilometers, with an exclusive economic zone (EEZ) of 2.02 million square kilometers. The state of Maharashtra is located on the western side of the Indian Peninsula. The state has 720 kilometers coastline. Towards the southern end of Maharashtra coastline lies the Sindhudurg coastal district. Situated between latitudes 150 37’ and 16040’ north and longitudes 73019’ and 74018’ east, Sindhudurg district has a coastline of 121 kilometers. Apart from the beautiful pocket sandy beaches, island & inland ports, the coast is also known for built heritage, local culture and Malvani cuisine. The area has rich coastal and marine biodiversity. Ecosystem services are extremely important for the sustenance of livelihood of local people. However, coastal tourism has picked up in a most unplanned manner in last two decades in three coastal districts Deogad, Malvan, Vengurla of Sindhudurg district. The paper starts with the key statements by some of the repu...