Isolation of hexavalent chromium (VI) tolerant fungi from tannery effluent and their growth responses to different concentrations of chromium (VI)

The main objective of this study was to isolate, characterize, and determine chromium (VI) tolerance capacities of fungal strains from tannery effluent of the Kolkata Leather Complex area. Chromium (VI) is a heavy metal that is known to be toxic as well as carcinogenic. It is an important heavy metal widely used in various industries of which the tanning industry deserves special mention. The majority of Cr (VI) waste is discharged into the environment annually as a consequence of industrial and manufacturing activities. Kolkata Leather Complex is an industrial complex intended to serve as a central leather-tanning complex for Kolkata located at Bantala, near East Kolkata, India. Samples (tannery effluent) were collected in sterile capped tubes from Kolkata Leather Complex Area and brought to the laboratory for analysis. The samples were serially diluted and were plated on Czapekdox agar plates and incubated at 300C. After a few days, a number of morphologically different colonies were selected and sequentially subcultured for pure colony isolation on the same medium. They were preserved in the refrigerator at 40 C. Lactophenol cotton blue staining was done to observe and record the fungal morphological characteristics. They were further assessed for their hexavalent chromium tolerance capacities and subsequently the metal tolerance index was derived for each strain respectively. All 16 fungal strains isolated from the Kolkata Leather Complex tannery area were found to be chromium (VI) tolerant starting at 0.1mg/ml Cr (VI) concentration. Maximum chromium (VI) tolerance was displayed by sample S12 (2mg/ml) which was later identified as having 99.82% similarity with Aspergillus nomius strain.Keywords: effluent, fungi, heavy metal, isolation, hexavalent chromium, tannery, tolerance

Isolation and characterization of chromium (vi) tolerant bacterial strains isolated from the tannery effluent of park circus area.

Heavy metals contamination is a global environmental concern because it is difficult to remove these contaminants from the environment, unlike other pollutants. Chromium (Cr) is one of the most important heavy metals used extensively in various industries, out of which the tanning industry deserves special mention. There are more than 2500 tanneries in the country and nearly 80% of the tanneries are engaged in the chrome tanning process. Massive amounts of Cr waste are discharged annually in the environment as a result of industrial and manufacturing activities. Cr, a highly reactive element with an oxidation state of 6 exhibits stability as Cr (III) and Cr (VI). Hexavalent chromium is actually more toxic in effect to living organisms than its trivalent form. USEPA has classified Cr (VI) as a group A carcinogen, based on its chronic effects. Prolonged exposure to Cr (VI) is found to cause cancer in the digestive tract and lungs and in other cases epigastric pain, nausea and vomiting. Cr (VI) exposure has severe impacts on aquatic species also. In the present study chromium (VI) tolerant bacterial strains were isolated from the tannery effluent of Park Circus area. Most of the bacterial isolates were Gram-negative while few were Gram-positive. 6 bacterial strains were tested for their Cr tolerance capacity of which S6 showed maximum Cr tolerance of 0.4-0.5 mg/ml. The growth responses to different concentrations of Cr (VI) by the bacterial isolates, were also studied. The responses of the bacteria depended on the time of incubation and Cr (VI) concentration. Keywords: Chromium, tolerance, bacteria, growth response.      La contaminación por metales pesados ​​es una preocupación ambiental mundial porque es difícil eliminar estos contaminantes del medio ambiente, a diferencia de otros contaminantes. El cromo (Cr) es uno de los metales pesados ​​más importantes que se utiliza ampliamente en diversas industrias, de las cuales la industria del curtido merece una mención especial. Hay más de 2500 curtidurías en el país y casi el 80% de las curtidurías se dedican al proceso de curtido al cromo. Anualmente se descargan enormes cantidades de residuos de Cr en el medio ambiente como resultado de las actividades industriales y de fabricación. El Cr, un elemento altamente reactivo con un estado de oxidación de 6, presenta estabilidad como Cr (III) y Cr (VI). El cromo hexavalente tiene un efecto más tóxico para los organismos vivos que su forma trivalente. La USEPA ha clasificado al Cr (VI) como carcinógeno del grupo A, con base en sus efectos crónicos. Se ha descubierto que la exposición prolongada al Cr (VI) provoca cáncer en el tracto digestivo y los pulmones y, en otros casos, dolor epigástrico, náuseas y vómitos. La exposición al Cr (VI) también tiene graves impactos en las especies acuáticas. En el presente estudio se aislaron cepas bacterianas tolerantes al cromo (VI) del efluente de la curtiduría del área de Park Circus. La mayoría de los aislados bacterianos fueron gramnegativos, mientras que pocos fueron grampositivos. Se analizaron 6 cepas bacterianas para determinar su capacidad de tolerancia al Cr, de las cuales S6 mostró una tolerancia máxima al Cr de 0,4-0,5 mg / ml. También se estudiaron las respuestas de crecimiento a diferentes concentraciones de Cr (VI) por los aislados bacterianos. Las respuestas de las bacterias dependieron del tiempo de incubación y de la concentración de Cr (VI). Palabras clave: cromo, tolerancia, bacterias, respuesta de crecimiento.La contaminación por metales pesados ​​es una preocupación ambiental mundial porque es difícil eliminar estos contaminantes del medio ambiente, a diferencia de otros contaminantes. El cromo (Cr) es uno de los metales pesados ​​más importantes que se utiliza ampliamente en diversas industrias, de las cuales la industria del curtido merece una mención especial. Hay más de 2500 curtidurías en el país y casi el 80% de las curtidurías se dedican al proceso de curtido al cromo. Anualmente se descargan enormes cantidades de residuos de Cr en el medio ambiente como resultado de las actividades industriales y de fabricación. El Cr, un elemento altamente reactivo con un estado de oxidación de 6, presenta estabilidad como Cr (III) y Cr (VI). El cromo hexavalente tiene un efecto más tóxico para los organismos vivos que su forma trivalente. La USEPA ha clasificado al Cr (VI) como carcinógeno del grupo A, con base en sus efectos crónicos. Se ha descubierto que la exposición prolongada al Cr (VI) provoca cáncer en el tracto digestivo y los pulmones y, en otros casos, dolor epigástrico, náuseas y vómitos. La exposición al Cr (VI) también tiene graves impactos en las especies acuáticas. En el presente estudio se aislaron cepas bacterianas tolerantes al cromo (VI) del efluente de la curtiduría del área de Park Circus. La mayoría de los aislados bacterianos fueron gramnegativos, mientras que pocos fueron grampositivos. Se analizaron 6 cepas bacterianas para determinar su capacidad de tolerancia al Cr, de las cuales S6 mostró una tolerancia máxima al Cr de 0,4-0,5 mg / ml. También se estudiaron las respuestas de crecimiento a diferentes concentraciones de Cr (VI) por los aislados bacterianos. Las respuestas de las bacterias dependieron del tiempo de incubación y de la concentración de Cr (VI). Palabras clave: cromo, tolerancia, bacterias, respuesta de crecimiento

Progression of Diabetic Retinopathy during COVID-19 Pandemic: A Retrospective Study

Introduction: Emergence and subsequent exponential spread of Coronavirus Disease-2019 (COVID-19) infection during 2020 forced the Government to issue countrywide lockdown from March 2020. Diabetic Retinopathy (DR) is one of the debilitating diseases of the eye which requires regular follow-ups and timely intervention to prevent permanent vision loss. The impact of countrywide lockdown on prevalence and progression of DR needs to be evaluated. Aim: To assess the effect of COVID-19 pandemic situation on the prevalence and progression of DR and analyse the possible risk factors for progression of DR in the ongoing pandemic period by comparing retrospective data from immediate prepandemic quarter with post lockdown quarter. Materials and Methods: This retrospective study was conducted in the Department of Opthalmology at Regional Institute of Ophthalmology, Kolkata, West Bengal, India. The study was done during the prepandemic period, from November 2019 to February 2020. In the present study, a cohort of 83 diabetic patients with pre-existing DR was selected from past medical records and compared with post lockdown period during November 2020 to February 2021. Data regarding prevalence of various types of DR, mean Central Macular Thickness (CMT), mean Visual Acuity (VA), proportion of patients requiring >3 doses of monthly anti-Vascular Endothelial Growth Factors (VEGF) and additional laser therapy or vitrectomy, VA improvement and reduction of mean CMT were gathered and compared between those two quarters. The data was analysed using Statistical Package for Social Sciences (SPSS) version 25.0. Results: The prevalence of moderate Non Proliferative Diabetic Retinopathy (NPDR) (13% vs 25%), severe NPDR (19% vs 8%), Proliferative DR (PDR) (18% vs 7%), Advanced Diabetic Eye Disease (ADED) (4.8% vs 1%) and Diabetic Macular Oedema (DME) (62% vs 28%) increased several folds during post lockdown quarter in comparison to prepandemic quarter. There was a statistically significant difference (p-value<0.05) in baseline mean LogMar Best Corrected Visual Acuity (BCVA) (0.4±0.08 vs 0.9±0.07), mean CMT (386.4±26.8 to 421.8±21.6) positive correlations of some of the possible risk factors for poor visual outcome among the same cohort of patients in the post lockdown period: poor socioeconomic status (35%; Odds Ratio (OR):3.59, Relative Risk (RR):2.68), irregular diabetic medication (52%; OR:3.56, RR:2.23), residence more than 100 km from the hospital (38%; OR:3.03, RR:2.26). Conclusion: The present study, concludes that, the status of DR stage among study subjects in the post lockdown period has deteriorated when compared with the prepandemic period

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-