Riverine landscape dynamics of the Upper Ganga River (Haridwar-Narora), India.

Earth observation data provides an exceptional opportunity to study the temporal dynamics of large rivers. The availability of spatially continuous, synoptic and temporally repetitive satellite data allows the reconstruction of historical dynamics of large rivers along with the identification of the causal factors. An absolute paucity of information on the effect of hydrogeomorphic processes on the dynamics of the Upper Ganga River (UGR), especially upon its entry in the plains, motivated this research. This study aims to analyse morphological changes in the river channel, map temporal changes in the land use/land cover (LULC) within the riverscape and thereby understand the landscape dynamics in the UGR (Haridwar to Narora) during 1993-2017 by means of earth observation data. The analysis showed that the river remains straight with a sinuosity index of < 1; however, the braiding increased considerably (from 3.79 to 4.53). Erosion being more prominent on the left bank in comparison to the right bank with 85.89 km2 eroded on the left bank in comparison to 59.21 km2 eroded along the right bank. Riverine landscape has been observed to have a higher rate of accretion in comparison to erosion (8.09 km2 yr-1 and 6.04 km2 yr-1, respectively). Morphological change has brought a transition in the land use patterns with marked variation in vegetation and agriculture along with built-up. Significant changes in the composition of the LULC are largely due to the manifold increase in the agriculture extent (≈ 12 times), built-up (5 times) and the decrease in vegetation cover from 43.9% in 1993 to just 10.94% in 2017.

Heavy metal pollution in surface water of the Upper Ganga River, India: human health risk assessment.

To assess the risk on human health, heavy metal contamination was analysed from surface water in the Upper Ganga river, India. Spatial and seasonal distribution of Fe, Mn, Zn, Cr and Pb was evaluated at eight sites during pre-monsoon and post-monsoon season of 2017. Average concentration of heavy metals was high, often exceeding the limits prescribed for surface water by Bureau of Indian Standard (BIS) and the World Health Organization (WHO). Based on heavy metal pollution index (HPI), 87% of the river stretch was classified as medium to highly polluted. Simultaneous assessment of the health risk employing chronic daily intake (CDI) and hazard quotient (HQ) indicates that exposure through ingestion and dermal pathways currently poses no serious threat to human health (CDI < 1, HQ < 1). For the two population groups analysed, HQIngestion values for Cr (adults 0.51, child 0.55) and Pb (adult 0.31, child 0.34) were significantly higher as compared with other heavy metals. HIIngestion varied from 0.85 to 1.64 for adult and 0.92 to 1.77 for child group, indicating health risk to both groups with child group being more risk prone from either of the exposure pathways. In addition, HI values revealed an increased risk to health for both groups during the post-monsoon season. Higher hazard index (HI) values (> 1) in the Upper Ganga river indicate an ever-increasing non-carcinogenic risk to the exposed population within the riverine landscape. The study highlights the impact of heavy metals in degrading the water quality of the Upper Ganga river and also advocates immediate attention towards reducing human health risk.

Impact of heavy metals on inhibitory concentration of Escherichia coli-a case study of river Yamuna system, Delhi, India.

The occurrence of resistant bacteria to specific heavy metals can be associated with increasing load of the metals in the environment. River Yamuna is polluted by various toxic heavy metals discharged by several industrial and agricultural sources. Therefore, the use of heavy metal-resistant bacteria as an indicator of metal pollution was tested in the present study. For the purpose of the study, the heavy metal resistance status of 42 Escherichia coli strains isolated from River Yamuna water from 7 sampling sites within a span of 2 years was determined using growth curves and plate dilution method in terms of minimum inhibitory concentration (MIC) values by comparing with MIC value of control strain. Seasonally, the lowest mean MIC value was observed for bacterial strains isolated in post-monsoon (December) 2013 and highest mean MIC value was observed for bacterial strains isolated in monsoon (August) 2015. Site-wise analysis of the maximum mean MIC values for all the isolated strains showed the highest mean Ni MIC value for the bacterial strains isolated from site S4 (ITO), highest mean Cu MIC, Cr MIC, and Fe MIC values for the bacterial strains isolated from site S2 (Najafgarh drain intermixing zone) and highest mean Cd MIC, Pb MIC, and Zn MIC values for the bacterial strains isolated from site S7 (Shahdara drain intermixing zone). Correlation analysis between mean MIC site-wise results with mean heavy metal site-wise concentrations showed significant positive correlation indicating that the higher the mean concentration of a given heavy metal at a given site, the higher the mean MIC value for the strains isolated from the same site indicating higher level of resistance. Overall, the present study has shown that the presence of heavy metals in River Yamuna caused due to indiscriminate discharge of various effluents from different kind of sources as well as due to insufficient treatment capacity of sewage treatment plants as well as common effluent treatment plants, has serious impacts on its bacterial microflora as it leads to the development of resistant strains.

Trophic state assessment of Bhindawas Lake, Haryana, India.

Trophic state allows for identification of problems and pressures that an ecosystem faces as well as demarcation of remedial measures. This study focuses on spatial and temporal variations in the trophic state and detection of possible causes of its divergence in Bhindawas Lake, India. The trophic state of the lake undulated between eutrophic and hyper-eutrophic state throughout the study period. Higher phosphorus concentration within the lake ecosystem is the dominant causal factor for its eutrophic state. The influence of other water quality parameters has also been analyzed using Spearman's coefficient of correlation. Deviations between trophic state index (TSI)-chlorophyll-a (Chl-a), TSI-total phosphorus (TP), and TSI-Secchi depth (SD) pointed out that the lake is principally phosphorus limited, and its trophic status is influenced by non-algal turbidity to a large extent. Spatial analysis of trophic levels in geographic information system (GIS) helped in identification of pollution sources and chemical attributes affecting the trophic state of the lake. This study provides a rationale for further investigation of nutrient and sediment loading into the lake system and development of sustainable management and conservation strategy identifying suitable measures ascertaining the ecosystem integrity.

Wetland assessment, monitoring and management in India using geospatial techniques.

Satellite remote sensing and GIS have emerged as the most powerful tools for inventorying, monitoring and management of natural resources and environment. In the special context of wetland ecosystems, remotely sensed data from orbital platforms have been extensively used in India for the inventory, monitoring and preparation of action plans for conservation and management. First scientific inventory of wetlands in India was carried out in 1998 by Space Applications Centre (ISRO), Ahmedabad using indigenous IRS (Indian Remote Sensing Satellite) data of 1992-93 timeframe, which stimulated extensive use of geospatial techniques for wetland conservation and management. Subsequently, with advances in GIS, studies were carried out for development of Wetland Information System for a state (West Bengal) and for Loktak lake wetland (a Ramsar site) as a prelude to National Wetland Information System. Research has also been carried out for preparation of action plans especially for Ramsar sites in the country. In a novel research, use of the geospatial technology has also been demonstrated for biodiversity conservation using landscape ecological metrics. A country-wide estimate of emission of methane, a Green House Gas, from wetlands has also been made using MODIS data. Present article critically reviews the work carried out in India for wetland conservation and management using geospatial techniques.

Salvage Using Polatuzumab Vedotin Based Therapy in Relapsed Refractory Large B-Cell Lymphomas: Early Experience from a Real-World Middle-Income Setting Using Named-Patient Compassionate Access Program.

Polatuzumab vedotin is a novel immunotherapy antibody-drug conjugate targeting CD79b. It has been used in relapsed/refractory (R/R) large B-cell lymphomas since its FDA approval in 2019. Presently, this drug is unaffordable or unavailable for patients in Lower-Middle Income Countries (LMIC) like India. This is a retrospective study of adult (> 18 years) patients with R/R large B-cell lymphoma failing two prior lines of therapy, who received Polatuzumab based salvage therapy on a compassionate or named-patient access program. Between May 2019 and April 2022, 10 patients received Polatuzumab vedotin, and 9 were evaluable. The most common regimen used was Polatuzumab-Bendamustine-Rituximab. Out of 43 infusions administered, the adverse event profile was manageable [One grade-2 infusion reaction, 4 patients developed grade 3-4 hematological toxicity and none had grade 3-4 non-hematological toxicities]. Ten infusions were administered in the day care service. After a median of 4.5 cycles (range 1-8), 4 patients achieved CR, 2 had partial response (PR), and 3 had progressive disease (PD). With a median follow up of 491 days (range 8-1048 days), four patients are alive (three in CR and one in PR), three patients have died and three patients were lost to follow up. Early real-world experience from a LMIC setting demonstrates feasibility and a favourable safety profile of Polatuzumab vedotin based approach, along with encouraging response rates in a subset of patients.

Spatial and temporal variations of air pollution over 41 cities of India during the COVID-19 lockdown period.

In this study, we characterize the impacts of COVID-19 on air pollution using NO2 and Aerosol Optical Depth (AOD) from TROPOMI and MODIS satellite datasets for 41 cities in India. Specifically, our results suggested a 13% NO2 reduction during the lockdown (March 25-May 3rd, 2020) compared to the pre-lockdown (January 1st-March 24th, 2020) period. Also, a 19% reduction in NO2 was observed during the 2020-lockdown as compared to the same period during 2019. The top cities where NO2 reduction occurred were New Delhi (61.74%), Delhi (60.37%), Bangalore (48.25%), Ahmedabad (46.20%), Nagpur (46.13%), Gandhinagar (45.64) and Mumbai (43.08%) with less reduction in coastal cities. The temporal analysis revealed a progressive decrease in NO2 for all seven cities during the 2020 lockdown period. Results also suggested spatial differences, i.e., as the distance from the city center increased, the NO2 levels decreased exponentially. In contrast, to the decreased NO2 observed for most of the cities, we observed an increase in NO2 for cities in Northeast India during the 2020 lockdown period and attribute it to vegetation fires. The NO2 temporal patterns matched the AOD signal; however, the correlations were poor. Overall, our results highlight COVID-19 impacts on NO2, and the results can inform pollution mitigation efforts across different cities of India.