Objective:To investigate the prevalence of leptospirosis among patients from within and outside Kolkata.India,attending the Calcutta School of Tropical Medicine,for treatment during August 2002 to August 2008.Methods:...Objective:To investigate the prevalence of leptospirosis among patients from within and outside Kolkata.India,attending the Calcutta School of Tropical Medicine,for treatment during August 2002 to August 2008.Methods:The leptospirosis cases were determined on the basis of clinical, epidemiological,and biochemical factors,and were tested for leptospiral antibodies using IgM ELISA.Serum samples with absorbance ratio≥1.21 were interpreted as reactive.Results:The commonest presentation involved fever,headache and jaundice.The male-female ratio was 61:46.A total of 65(64.20%) cases had abnormal liver and renal functions respectively,and 57.1% had both the abnormalities.The highest incidence(75.35.04%) was recorded in SeptemberOctober followed by July-August(53.24.77%).The reactive cases had absorbance ratios between 1.21 and 8.21.and 53 showed equivocal result,while IgM non reactivity were seen in 90 patients (absorbance ratios 0.10-0.90).The patients responded to treatment with parenteral antibiotics, penicillin,ceftriaxone and cefotaxime;follow up did not reveal case fatality.Conclusions:The cardinal signs of leptospirosis help in making clinical diagnosis,but in any hyper-endemic situation any patient reporting with acute lever and signs of pulmonary,hepatic or renal involvement should be suspected to have leptospirosis and investigated accordingly.Increased awareness,and early diagnosis and treatment,can reduce mortality due to leptospirosis.展开更多
An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban a...An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban agglomerate in Asia. Concentration of both anionic synthetic detergents and organochlorine pesticide resi-dues analysed from 54 and 19 sampling stations covering groundwater and surface water sources respec-tively, are generally found to be within the tolerance limit for human consumption. The concentration of synthetic detergent ranges from 0.084 to 0.425mg/l. Residues of organochlorine pesticides are analysed from different sources like tanks, lakes, rivers and groundwater. Lindane (0.01-0.43μg/l) and DDT (0.03-0.65 μg/l) are the most widely detected pesticide residues. Howerer, the two have not exceeded the limits for drinking anywhere. High value of aldrin and dieldrin (0.9μg/l) is obtained in the river Hugli at Barakpur-Seoraphuli, 20 km north of Kolkata. Likewise high value of Heptachloreis detected in a canal water sample at Palta (0.05 μg/l), a suburban area. Seasonally, the pesticide concentration in surface water is maximum during winter due to their higher application and minimum during monsoon. In groundwater, however, this relationship is reverse due to higher infiltration of surface water during monsoon.展开更多
Objective:To observe other hemoprotozoan diseases with canine ehrlichiosis und to evaluate the clinical and hematological aspects of dogs naturally infected with ehrlichiosis with other hemoprotozoun diseases.Methods:...Objective:To observe other hemoprotozoan diseases with canine ehrlichiosis und to evaluate the clinical and hematological aspects of dogs naturally infected with ehrlichiosis with other hemoprotozoun diseases.Methods:Blood was collected for hematological value and Giemsa stained blood smear was made for diagnosis of Ehrlichia sp.and other hemoprotozoan parasites from naturally infected dogs.Case history was taken from the owner and clinical signs and symptoms were noted.Results:A total of 47 cases of ehrlichiosis in dogs were reported with babesiosis(8.51%)and hepatozoonosis(6.38%)hemoprotozoan diseases.Ehrlichia cams,Ehrlichia ewingii,Brucella canis,Babesia gibsoni and Hepatozoon canis were observed under oil immersion lense of microscope in Giemsa stained peripheral blood smears.Marked anaemia and neutrophilic leukocytosis were observed.Conclusions:The results of this study stated that clinical and haeinatological changes occurred in canine ehrlichiosis with babesiosis and hepatozoonosis due to parasitemia.In mixed infection,the disease more severe,and also it depended on immunity of animals.Babesia gibsoni and Hepatozoon canis with Ehrlichia sp.were first reported from West Bengal state of India by this study.展开更多
The East Kolkata Wetlands (EKW) is located on the eastern periphery of the city of Kolkata and extends up to theBidyadhari-Matla River confluence. It is a Ramsar Site and acts as an absorber basin for a large number o...The East Kolkata Wetlands (EKW) is located on the eastern periphery of the city of Kolkata and extends up to theBidyadhari-Matla River confluence. It is a Ramsar Site and acts as an absorber basin for a large number of con-taminants drained from Kolkata. Agricultural lands, sewage-fed fisheries, garbage dumping fields, horticulture,and built-up areas are included in this protected area, that covers approximately 125 km2. It reveals that climatechange reduces the variety of wetland ecosystem services and increases socio-economic vulnerability and eco-nomic stress. The human encroachment, reclamation of land for agriculture, aquaculture, and urban expansion inand around Kolkata has recently adversely threatened the EKW. The remotely sensed data, socio-economic data,and responses of inhabitants have been used to analyse the EKW’s risk and vulnerability. We employed geospatialanalysis by using the Multi-Criteria Decision Making (MCDM) method using nine risk factors. An in-depth analysisof the EKW using geospatial techniques and the Fuzzy Analytic Hierarchy Process (FAHP) helped to understandthe EKW transformations through vulnerability and risk analysis. The results show that the transformation of thewetland to aquaculture, eutrophication and pollution, road proximity, waste dumping, population density, andgrowth are the main factors for the deteriorating health, quality, and environment of the EKW. It also reveals thatquantitative and qualitative evaluations of ecosystem services, wetland degradation, transformation, and cause-effect rapport should be periodically assessed using scientific methods like FAHP, RS, GIS to formulate resilient,integrated plans and strategy for the sustainable management of the EKW.展开更多
In this paper we have first of all studied the interrelations among the concentrations of SO2, NO2 and PM10 and then predicted their future level of concentrations in the ambient air of Kolkata. The data collected fro...In this paper we have first of all studied the interrelations among the concentrations of SO2, NO2 and PM10 and then predicted their future level of concentrations in the ambient air of Kolkata. The data collected from West Bengal Pollution Control Board website have been used to construct second degree, third degree and four degree polynomial equations using MATLAB software. Since a curve in a small interval can be approximated by a line segment in that small interval, we have observed that better result can be achieved if we replace the curves piece meal wise in small intervals by line segments during January-April, May-August and September-December months. The multiple regression equations among the aforesaid three parameters have been established to predict the value of each parameter in terms of the remaining two. A further improvement in terms of reducing the number of dependent variables has been made using the results of correlation coefficients. Finally, we have predicted the value of each parameter in terms of only one dependent variable.展开更多
Anthropogenic activities may affect species diversity and community structure.Butterfly species diversity in relation to human-impact gradient was evaluated in the Baruipur subdivision,outskirts of Kolkata metropolis,...Anthropogenic activities may affect species diversity and community structure.Butterfly species diversity in relation to human-impact gradient was evaluated in the Baruipur subdivision,outskirts of Kolkata metropolis,West Bengal,India as a model geographic area.Four study sites situated in bird sanctuaries,rural,suburban and urban areas with different levels of anthropogenic disturbances were selected to assess the human impact on butterfly diversity.A total of 80 butterfly species were recorded during the entire study period with the sanctuary(with minimal anthropogenic disturbance)showing the highest species richness(73)followed by rural(62),suburban(54)and urban(36)study sites indicating a strong negative impact of anthropogenic disturbance on butterfly species diversity.Butterfly species diversity varied significantly among different habitats(p˂0.001).The relative abundance of butterflies also varied seasonally.It is apparent that the area under the present study is able to sustain diverse butterfly species provided natural habitats are protected from anthropogenic disturbances and steps are taken to increase urban greenery to support butterfly diversity and consequent ecosystem services.展开更多
Aims: To conduct a prospective, community based study in an impoverished urban site in Kolkata (formerly Calcutta) in order to measure the burden of cholera, describe its epidemiology, and search for potential risk fa...Aims: To conduct a prospective, community based study in an impoverished urban site in Kolkata (formerly Calcutta) in order to measure the burden of cholera, describe its epidemiology, and search for potential risk factors that could be addressed by public health strategies. Methods: The study population was enumerated at the beginning and end of the study period. Surveillance through five field outposts and two referral hospitals for acute, watery, non bloody diarrhoea was conducted from 1 May 2003 to 30 April 2004. Data and a stool sample for culture of Vibrio cholerae were collected from each patient. Treatment was provided in accordance with national guidelines. Results: From 62 329 individuals under surveillance, 3284 diarrhoea episodes were detected, of which 3276 (99% ) had a stool sample collected and 126 (4% ) were culture confirmed cholera. Nineteen (15% ) were children less than 2 years of age, 29 (23% ) had severe dehydration, and 48 (38% ) were hospitalised. Risk factors for cholera included a household member with cholera during the period of surveillance, young age, and lower educational level. Conclusions: There was a substantial burden of cholera in Kolkata with risk factors not easily amenable to intervention. Young children bear the brunt not only of diarrhoeal diseases in general, but of cholera as well. Mass vaccination could be a potentially useful tool to prevent and control seasonal cholera in this community.展开更多
The environmental fate, global warming effect and human health risk from mono aromatic VOCs are of major concerns among many consequences of their anthropogenic emission. In more than a yearlong study (November 2003 t...The environmental fate, global warming effect and human health risk from mono aromatic VOCs are of major concerns among many consequences of their anthropogenic emission. In more than a yearlong study (November 2003 to February 2005) of the city air in Kolkata, India at different seasons in three different sites, the seasonal mean benzene and toluene concentrations varied between 13.8–72.0 μg/m3 and 21.0–83.2 μg/m3 respectively along all the sites. The environmental distribution and load of BTEX (Benzene, Toluene, Ethylbenzene and isomers of Xylene) in different environmental compartment was estimated using a multimedia mass balance model, TaPL3. The total environmental load of BTEX together was estimated to be 9.7 × 104 kg. Contribution of Kolkata metropolitan city towards global warming due to environmental emission of BTEX has been estimated as 1.9 × 105 tons of carbon dioxide equivalent per year which is about 1.1% of yearly direct CO2 emission the city. The consequence of BTEX emission towards human health has been estimated in terms of non-cancer and cancer risk in population due to their inhalation exposure. The cumulative lifetime cancer risk for benzene and ethylbenzene was found to be higher than the acceptable value and range between 3.0 × 105 and 8.9 × 106 in three sites, although the non-cancer health risk was found to be within acceptable limit.展开更多
Assessment of ecological risk(ER)is a key approach to adapting and mitigating ecological deterioration in cities of developing countries.In developing countries,the ecological landscapes such as vegetation cover,water...Assessment of ecological risk(ER)is a key approach to adapting and mitigating ecological deterioration in cities of developing countries.In developing countries,the ecological landscapes such as vegetation cover,water bodies,and wetlands are highly vulnerable due to rapid urban expansion.Therefore,urban ER(UER)assessment and its drivers are crucial to guide ecological protection as well as restoration.This study aims to explore the spatiotemporal pattern of UER and the impact of urban spatial form on UER in the Kolkata Megacity Region(KMR),India.This study developed a UER index and used spatial regression models across the urban centres.The ER has been assessed at city scale as well as grid-scale(2 km x 2 km and 5 km x 5 km)from 2000 to 2020.The results showed that ER has substantially increased over the last 20 years.The urban centres with very high and high ER substantially increased,i.e.from 21.95%in 2000 to 31.70%in 2020.Kolkata and its surrounding urban centres were mostly characterized by very high and high ER.ER was influenced by spatial variables(such as land use and landscapes pattern).However,remote sensing parameters were weakly related to ER.The spatial lag model(SLM)(R^(2)=0.8686)was found to be better fit model than spatial error model(SEM)(R^(2)=0.8661)and ordinary linear regression model(OLS)(R^(2)=0.8641).Thus,the findings of the study can improve research and a comprehensive framework for urban ecological resources and provide a scientific basis for urban ecosystem planning and restoration.In addition to this,it will guarantee the sustainable utilization of urban ecosystems.展开更多
Rapid urbanization has emerged as one of the most critical challenges to ecological sustainability in urban areas.In developing countries,the degradation of the ecosystem is more prominent due to the lack of urban pla...Rapid urbanization has emerged as one of the most critical challenges to ecological sustainability in urban areas.In developing countries,the degradation of the ecosystem is more prominent due to the lack of urban planning.Thus,it has become urgent for researchers to identify the ecological efficiency(EE)changes imposed by urban expansion and promote sustainable land use planning.This study aims to develop a comprehensive urban ecological efficiency(UEE)framework in the Kolkata Metropolitan Area(KMA),India,from 2000 to 2020.Principal component analysis(PCA)was used to develop a remote sensing-based UEE index(UEEI)based on five effective ecological parameters(Greenness,Dryness,Heat,Wetness and vegetation health.A single sensitivity parameter was also calculated to determine the role of a single parameter based on which management strategies can be carried out.The findings showed that(i)there were substantial deteriorations of UEE in the last 20 years.In 2000 the areas with good EE were about 65.5%which declined to 53.72%in 2010 and 20.87%in 2020.The areas with good UEE decreased 68%and 61%from 2000 to 2020 and 2010 to 2020,respectively;(ii)the areas with good UEE were 52%in 2000,while 38%in 2010.Most urban centres(Bhadreshwar,Champdani,Srirampur,Bally,Howrah,Kamarhati,Baranagar,Dum Dum,South Dum Dum,Rajarhat,Bidhannagar)located around the Kolkata megacity are characterized by poor and very poor EE(ranges of 0.60-1.00).Thus,spatiotemporal pattern of UEE could assist to clarify the administrative responsibilities as well as obligations.In addition to this,the UEE framework can help for scientific guidance of urban ecosystem protection and restoration through comprehensive spatial landscape planning.展开更多
Urban growth boundary(UGB)is a regulatory measure of local government for delineating limits of urban growth over a period of time.Land within the UGB allows urban development,while the land outside of this boundary r...Urban growth boundary(UGB)is a regulatory measure of local government for delineating limits of urban growth over a period of time.Land within the UGB allows urban development,while the land outside of this boundary remains primarily non-urban.The increasing popularity of UGB demands an easy and effective method to design this boundary.This article introduces a new concept,Ideal Urban Radial Proximity(IURP),to designate a spatial UGB using geoinformatics in the digital environment.The Kolkata urban agglomeration was considered to demonstrate this model.Remotely sensed imageries of three temporal instants(years 1975,1990 and 2005)were considered to determine the information on urban extent and growth of the city.These data were then used as inputs to model the UGB for the years 2020 and 2035.The proposed model discourages scattered development and increase in urban growth rate.It preserves urban vegetation,water bodies and any other important non-urban areas within the inner city space.The IURP concept will also be useful to make the cities circular and polycentric urban blobs into a monocentric tract.Apart from the proposed model and derived results,this research also proves the potential of geoinformatics in modelling a UGB.展开更多
Background:Wetlands provide diverse ecological services to sustain rich biodiversity,but they are recklessly exploited around the globe.East Kolkata Wetlands(EKW;Ramsar site No.1208,~125 km^(2))was once very rich in f...Background:Wetlands provide diverse ecological services to sustain rich biodiversity,but they are recklessly exploited around the globe.East Kolkata Wetlands(EKW;Ramsar site No.1208,~125 km^(2))was once very rich in faunal diversity that declined over the years due to various anthropogenic pressures.In such scenarios,effective management plans need to contemplate local and landscape level initiatives and prioritize areas for conservation.Studying the foraging guild structure and spatial patterns of relationship between bird and its environment provides important insight of ecological processes of avifauna.Thus,we carried out extensive surveys in 142 point count stations to explore the diversity and foraging guild structure of birds in EKW.We addressed two important questions that how bird diversity varied from the outer periphery of the city towards the wetlands and how bird diversity is influenced by land cover features at local and landscape level in wetland complex.The goal of this study was to prepare a spatial map of avian diversity and to find the conservation priority areas for birds in this internationally recognized wetland complex.Results:We recorded 94 species of birds and the Shannon diversity index values ranged between 1.249 and 3.189.We found that the avian diversity increased with increasing distance from city periphery.Omnivores and insectivores were the dominant foraging guilds,followed by carnivores,granivores,frugivores and piscivores.Generalized Linear Models revealed that bird communities were positively influenced by areas of wetlands,dikes and banks,agricultural field and emergent vegetation,and negatively influenced by built-up area.In the projected spatial map of species diversity,74.15 km^(2)area has high diversity.Finally,we identified 12.82 km^(2) of top 10%conservation priority areas.Conclusions:Low bird diversity near city periphery is related to habitat degradation due to anthropogenic pressure.Dominance of omnivores and insectivores indicates a possible impact of urbanization in EKW.We suggest that a mix of agricultural field,wetland areas and emergent vegetation helps to sustain a greater avian community.Besides,protection of conservation priority areas,restoration of the degraded habitats and reduction of threats(particularly in the north-eastern parts of EKW near the city periphery)will ensure the conservation of avifauna,and also the overall biodiversity of EKW.展开更多
文摘Objective:To investigate the prevalence of leptospirosis among patients from within and outside Kolkata.India,attending the Calcutta School of Tropical Medicine,for treatment during August 2002 to August 2008.Methods:The leptospirosis cases were determined on the basis of clinical, epidemiological,and biochemical factors,and were tested for leptospiral antibodies using IgM ELISA.Serum samples with absorbance ratio≥1.21 were interpreted as reactive.Results:The commonest presentation involved fever,headache and jaundice.The male-female ratio was 61:46.A total of 65(64.20%) cases had abnormal liver and renal functions respectively,and 57.1% had both the abnormalities.The highest incidence(75.35.04%) was recorded in SeptemberOctober followed by July-August(53.24.77%).The reactive cases had absorbance ratios between 1.21 and 8.21.and 53 showed equivocal result,while IgM non reactivity were seen in 90 patients (absorbance ratios 0.10-0.90).The patients responded to treatment with parenteral antibiotics, penicillin,ceftriaxone and cefotaxime;follow up did not reveal case fatality.Conclusions:The cardinal signs of leptospirosis help in making clinical diagnosis,but in any hyper-endemic situation any patient reporting with acute lever and signs of pulmonary,hepatic or renal involvement should be suspected to have leptospirosis and investigated accordingly.Increased awareness,and early diagnosis and treatment,can reduce mortality due to leptospirosis.
文摘An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban agglomerate in Asia. Concentration of both anionic synthetic detergents and organochlorine pesticide resi-dues analysed from 54 and 19 sampling stations covering groundwater and surface water sources respec-tively, are generally found to be within the tolerance limit for human consumption. The concentration of synthetic detergent ranges from 0.084 to 0.425mg/l. Residues of organochlorine pesticides are analysed from different sources like tanks, lakes, rivers and groundwater. Lindane (0.01-0.43μg/l) and DDT (0.03-0.65 μg/l) are the most widely detected pesticide residues. Howerer, the two have not exceeded the limits for drinking anywhere. High value of aldrin and dieldrin (0.9μg/l) is obtained in the river Hugli at Barakpur-Seoraphuli, 20 km north of Kolkata. Likewise high value of Heptachloreis detected in a canal water sample at Palta (0.05 μg/l), a suburban area. Seasonally, the pesticide concentration in surface water is maximum during winter due to their higher application and minimum during monsoon. In groundwater, however, this relationship is reverse due to higher infiltration of surface water during monsoon.
基金Supported by Department of Veterinary Microbiology.West Bengal University of Animal and Fishery Sciences.37.K.B.Sarani.Kolkata-700037.West Bengal.India(Grant No.F.O.-VAS/Micro-11-12/165)
文摘Objective:To observe other hemoprotozoan diseases with canine ehrlichiosis und to evaluate the clinical and hematological aspects of dogs naturally infected with ehrlichiosis with other hemoprotozoun diseases.Methods:Blood was collected for hematological value and Giemsa stained blood smear was made for diagnosis of Ehrlichia sp.and other hemoprotozoan parasites from naturally infected dogs.Case history was taken from the owner and clinical signs and symptoms were noted.Results:A total of 47 cases of ehrlichiosis in dogs were reported with babesiosis(8.51%)and hepatozoonosis(6.38%)hemoprotozoan diseases.Ehrlichia cams,Ehrlichia ewingii,Brucella canis,Babesia gibsoni and Hepatozoon canis were observed under oil immersion lense of microscope in Giemsa stained peripheral blood smears.Marked anaemia and neutrophilic leukocytosis were observed.Conclusions:The results of this study stated that clinical and haeinatological changes occurred in canine ehrlichiosis with babesiosis and hepatozoonosis due to parasitemia.In mixed infection,the disease more severe,and also it depended on immunity of animals.Babesia gibsoni and Hepatozoon canis with Ehrlichia sp.were first reported from West Bengal state of India by this study.
基金The authors would like to thank the Netaji Subhas Open Uni-versity,Kolkata,for providing the supportive research funding(No.AC/140/2021-22).
文摘The East Kolkata Wetlands (EKW) is located on the eastern periphery of the city of Kolkata and extends up to theBidyadhari-Matla River confluence. It is a Ramsar Site and acts as an absorber basin for a large number of con-taminants drained from Kolkata. Agricultural lands, sewage-fed fisheries, garbage dumping fields, horticulture,and built-up areas are included in this protected area, that covers approximately 125 km2. It reveals that climatechange reduces the variety of wetland ecosystem services and increases socio-economic vulnerability and eco-nomic stress. The human encroachment, reclamation of land for agriculture, aquaculture, and urban expansion inand around Kolkata has recently adversely threatened the EKW. The remotely sensed data, socio-economic data,and responses of inhabitants have been used to analyse the EKW’s risk and vulnerability. We employed geospatialanalysis by using the Multi-Criteria Decision Making (MCDM) method using nine risk factors. An in-depth analysisof the EKW using geospatial techniques and the Fuzzy Analytic Hierarchy Process (FAHP) helped to understandthe EKW transformations through vulnerability and risk analysis. The results show that the transformation of thewetland to aquaculture, eutrophication and pollution, road proximity, waste dumping, population density, andgrowth are the main factors for the deteriorating health, quality, and environment of the EKW. It also reveals thatquantitative and qualitative evaluations of ecosystem services, wetland degradation, transformation, and cause-effect rapport should be periodically assessed using scientific methods like FAHP, RS, GIS to formulate resilient,integrated plans and strategy for the sustainable management of the EKW.
文摘In this paper we have first of all studied the interrelations among the concentrations of SO2, NO2 and PM10 and then predicted their future level of concentrations in the ambient air of Kolkata. The data collected from West Bengal Pollution Control Board website have been used to construct second degree, third degree and four degree polynomial equations using MATLAB software. Since a curve in a small interval can be approximated by a line segment in that small interval, we have observed that better result can be achieved if we replace the curves piece meal wise in small intervals by line segments during January-April, May-August and September-December months. The multiple regression equations among the aforesaid three parameters have been established to predict the value of each parameter in terms of the remaining two. A further improvement in terms of reducing the number of dependent variables has been made using the results of correlation coefficients. Finally, we have predicted the value of each parameter in terms of only one dependent variable.
文摘Anthropogenic activities may affect species diversity and community structure.Butterfly species diversity in relation to human-impact gradient was evaluated in the Baruipur subdivision,outskirts of Kolkata metropolis,West Bengal,India as a model geographic area.Four study sites situated in bird sanctuaries,rural,suburban and urban areas with different levels of anthropogenic disturbances were selected to assess the human impact on butterfly diversity.A total of 80 butterfly species were recorded during the entire study period with the sanctuary(with minimal anthropogenic disturbance)showing the highest species richness(73)followed by rural(62),suburban(54)and urban(36)study sites indicating a strong negative impact of anthropogenic disturbance on butterfly species diversity.Butterfly species diversity varied significantly among different habitats(p˂0.001).The relative abundance of butterflies also varied seasonally.It is apparent that the area under the present study is able to sustain diverse butterfly species provided natural habitats are protected from anthropogenic disturbances and steps are taken to increase urban greenery to support butterfly diversity and consequent ecosystem services.
文摘Aims: To conduct a prospective, community based study in an impoverished urban site in Kolkata (formerly Calcutta) in order to measure the burden of cholera, describe its epidemiology, and search for potential risk factors that could be addressed by public health strategies. Methods: The study population was enumerated at the beginning and end of the study period. Surveillance through five field outposts and two referral hospitals for acute, watery, non bloody diarrhoea was conducted from 1 May 2003 to 30 April 2004. Data and a stool sample for culture of Vibrio cholerae were collected from each patient. Treatment was provided in accordance with national guidelines. Results: From 62 329 individuals under surveillance, 3284 diarrhoea episodes were detected, of which 3276 (99% ) had a stool sample collected and 126 (4% ) were culture confirmed cholera. Nineteen (15% ) were children less than 2 years of age, 29 (23% ) had severe dehydration, and 48 (38% ) were hospitalised. Risk factors for cholera included a household member with cholera during the period of surveillance, young age, and lower educational level. Conclusions: There was a substantial burden of cholera in Kolkata with risk factors not easily amenable to intervention. Young children bear the brunt not only of diarrhoeal diseases in general, but of cholera as well. Mass vaccination could be a potentially useful tool to prevent and control seasonal cholera in this community.
文摘The environmental fate, global warming effect and human health risk from mono aromatic VOCs are of major concerns among many consequences of their anthropogenic emission. In more than a yearlong study (November 2003 to February 2005) of the city air in Kolkata, India at different seasons in three different sites, the seasonal mean benzene and toluene concentrations varied between 13.8–72.0 μg/m3 and 21.0–83.2 μg/m3 respectively along all the sites. The environmental distribution and load of BTEX (Benzene, Toluene, Ethylbenzene and isomers of Xylene) in different environmental compartment was estimated using a multimedia mass balance model, TaPL3. The total environmental load of BTEX together was estimated to be 9.7 × 104 kg. Contribution of Kolkata metropolitan city towards global warming due to environmental emission of BTEX has been estimated as 1.9 × 105 tons of carbon dioxide equivalent per year which is about 1.1% of yearly direct CO2 emission the city. The consequence of BTEX emission towards human health has been estimated in terms of non-cancer and cancer risk in population due to their inhalation exposure. The cumulative lifetime cancer risk for benzene and ethylbenzene was found to be higher than the acceptable value and range between 3.0 × 105 and 8.9 × 106 in three sites, although the non-cancer health risk was found to be within acceptable limit.
文摘Assessment of ecological risk(ER)is a key approach to adapting and mitigating ecological deterioration in cities of developing countries.In developing countries,the ecological landscapes such as vegetation cover,water bodies,and wetlands are highly vulnerable due to rapid urban expansion.Therefore,urban ER(UER)assessment and its drivers are crucial to guide ecological protection as well as restoration.This study aims to explore the spatiotemporal pattern of UER and the impact of urban spatial form on UER in the Kolkata Megacity Region(KMR),India.This study developed a UER index and used spatial regression models across the urban centres.The ER has been assessed at city scale as well as grid-scale(2 km x 2 km and 5 km x 5 km)from 2000 to 2020.The results showed that ER has substantially increased over the last 20 years.The urban centres with very high and high ER substantially increased,i.e.from 21.95%in 2000 to 31.70%in 2020.Kolkata and its surrounding urban centres were mostly characterized by very high and high ER.ER was influenced by spatial variables(such as land use and landscapes pattern).However,remote sensing parameters were weakly related to ER.The spatial lag model(SLM)(R^(2)=0.8686)was found to be better fit model than spatial error model(SEM)(R^(2)=0.8661)and ordinary linear regression model(OLS)(R^(2)=0.8641).Thus,the findings of the study can improve research and a comprehensive framework for urban ecological resources and provide a scientific basis for urban ecosystem planning and restoration.In addition to this,it will guarantee the sustainable utilization of urban ecosystems.
文摘Rapid urbanization has emerged as one of the most critical challenges to ecological sustainability in urban areas.In developing countries,the degradation of the ecosystem is more prominent due to the lack of urban planning.Thus,it has become urgent for researchers to identify the ecological efficiency(EE)changes imposed by urban expansion and promote sustainable land use planning.This study aims to develop a comprehensive urban ecological efficiency(UEE)framework in the Kolkata Metropolitan Area(KMA),India,from 2000 to 2020.Principal component analysis(PCA)was used to develop a remote sensing-based UEE index(UEEI)based on five effective ecological parameters(Greenness,Dryness,Heat,Wetness and vegetation health.A single sensitivity parameter was also calculated to determine the role of a single parameter based on which management strategies can be carried out.The findings showed that(i)there were substantial deteriorations of UEE in the last 20 years.In 2000 the areas with good EE were about 65.5%which declined to 53.72%in 2010 and 20.87%in 2020.The areas with good UEE decreased 68%and 61%from 2000 to 2020 and 2010 to 2020,respectively;(ii)the areas with good UEE were 52%in 2000,while 38%in 2010.Most urban centres(Bhadreshwar,Champdani,Srirampur,Bally,Howrah,Kamarhati,Baranagar,Dum Dum,South Dum Dum,Rajarhat,Bidhannagar)located around the Kolkata megacity are characterized by poor and very poor EE(ranges of 0.60-1.00).Thus,spatiotemporal pattern of UEE could assist to clarify the administrative responsibilities as well as obligations.In addition to this,the UEE framework can help for scientific guidance of urban ecosystem protection and restoration through comprehensive spatial landscape planning.
文摘Urban growth boundary(UGB)is a regulatory measure of local government for delineating limits of urban growth over a period of time.Land within the UGB allows urban development,while the land outside of this boundary remains primarily non-urban.The increasing popularity of UGB demands an easy and effective method to design this boundary.This article introduces a new concept,Ideal Urban Radial Proximity(IURP),to designate a spatial UGB using geoinformatics in the digital environment.The Kolkata urban agglomeration was considered to demonstrate this model.Remotely sensed imageries of three temporal instants(years 1975,1990 and 2005)were considered to determine the information on urban extent and growth of the city.These data were then used as inputs to model the UGB for the years 2020 and 2035.The proposed model discourages scattered development and increase in urban growth rate.It preserves urban vegetation,water bodies and any other important non-urban areas within the inner city space.The IURP concept will also be useful to make the cities circular and polycentric urban blobs into a monocentric tract.Apart from the proposed model and derived results,this research also proves the potential of geoinformatics in modelling a UGB.
文摘Background:Wetlands provide diverse ecological services to sustain rich biodiversity,but they are recklessly exploited around the globe.East Kolkata Wetlands(EKW;Ramsar site No.1208,~125 km^(2))was once very rich in faunal diversity that declined over the years due to various anthropogenic pressures.In such scenarios,effective management plans need to contemplate local and landscape level initiatives and prioritize areas for conservation.Studying the foraging guild structure and spatial patterns of relationship between bird and its environment provides important insight of ecological processes of avifauna.Thus,we carried out extensive surveys in 142 point count stations to explore the diversity and foraging guild structure of birds in EKW.We addressed two important questions that how bird diversity varied from the outer periphery of the city towards the wetlands and how bird diversity is influenced by land cover features at local and landscape level in wetland complex.The goal of this study was to prepare a spatial map of avian diversity and to find the conservation priority areas for birds in this internationally recognized wetland complex.Results:We recorded 94 species of birds and the Shannon diversity index values ranged between 1.249 and 3.189.We found that the avian diversity increased with increasing distance from city periphery.Omnivores and insectivores were the dominant foraging guilds,followed by carnivores,granivores,frugivores and piscivores.Generalized Linear Models revealed that bird communities were positively influenced by areas of wetlands,dikes and banks,agricultural field and emergent vegetation,and negatively influenced by built-up area.In the projected spatial map of species diversity,74.15 km^(2)area has high diversity.Finally,we identified 12.82 km^(2) of top 10%conservation priority areas.Conclusions:Low bird diversity near city periphery is related to habitat degradation due to anthropogenic pressure.Dominance of omnivores and insectivores indicates a possible impact of urbanization in EKW.We suggest that a mix of agricultural field,wetland areas and emergent vegetation helps to sustain a greater avian community.Besides,protection of conservation priority areas,restoration of the degraded habitats and reduction of threats(particularly in the north-eastern parts of EKW near the city periphery)will ensure the conservation of avifauna,and also the overall biodiversity of EKW.