Assessing the spatial variation of cropping intensity using multi-temporal Sentinel-2 data by rule-based classification

Environment, Development and Sustainability - The present study was conducted to analyze cropping intensity of four blocks (Mogra-Chinsurah, Polba-Dadpur, Singur and Haripal) of the Gangetic...     

Assessing land use change and potential environmental quality in Chandernagore Municipal Corporation,India

Environment, Development and Sustainability - The study has focused on portraying the spatio-temporal changes in land use pattern from 2011 to 2019 and has tried to assess the environmental quality...     

Fate and bioavailability of arsenic in organo-arsenical pesticide-applied soils. Part-I: incubation study

A laboratory incubation study was conducted to estimate geochemical speciation and in vitro bioavailability of arsenic as a function of soil properties. Two chemically-variant soil types were chosen, based on their potential differences with respect to arsenic reactivity: an acid sand with minimal arsenic retention capacity and a sandy loam with relatively high concentration of amorphous Fe/Al-oxides, considered a sink for arsenic. The soils were amended with dimethylarsenic acid (DMA) at three rates: 45, 225, and 450 mg/kg. A sequential extraction scheme was employed to identify the geochemical forms of arsenic in soils, which were correlated with the "in vitro" bioavailable fractions of arsenic to identify the most bioavailable species. Arsenic bioavailability and speciation studies were done at 0 time (immediately after spiking the soils with pesticide) and after four-months incubation. Results show that soil properties greatly impact geochemical speciation and bioavailability of DMA; soils with high concentrations of amorphous Fe/Al oxides retain more arsenic, thereby rendering them less bioavailable. Results also indicate that the use of organic arsenicals as pesticides in mineral soils may not be a safe practice from the viewpoint of human health risk.     

A framework based on fuzzy AHP-TOPSIS for prioritizing solutions to overcome the barriers in the implementation of ecodesign practices in SMEs

Small and medium enterprises (SMEs) are under pressure to adopt sustainable practices in their business due to increasing environmental challenges. This study aims to identify and prioritize the solutions to overcome the barriers in the implementation of ecodesign practices in SMEs. This study helps the companies to develop and implement the strategies on priority using higher ranked solutions. In this study, a framework is proposed that is based on fuzzy analytical hierarchy process and fuzzy technique for order preference by similarity to ideal solution to rank the solutions that overcome the barriers in ecodesign implementation in SMEs. The proposed framework is illustrated by conducting a case study of an Indian ring and piston manufacturing company. This framework provides an effective support in the decision-making of the company for producing eco-friendly products through the implementation of ecodesign practices. Results of this study emphasize that training of designers to use different ecodesign tools is an essential practice for SMEs.     

Dissolved methane in Indian freshwater reservoirs

Emission of methane (CH₄), a potent greenhouse gas, from tropical reservoirs is of interest because such reservoirs experience conducive conditions for CH₄ production through anaerobic microbial activities. It has been suggested that Indian reservoirs have the potential to emit as much as 33.5 MT of CH₄ per annum to the atmosphere. However, this estimate is based on assumptions rather than actual measurements. We present here the first data on dissolved CH₄ concentrations from eight freshwater reservoirs in India, most of which experience seasonal anaerobic conditions and CH₄ buildup in the hypolimnia. However, strong stratification prevents the CH₄-rich subsurface layers to ventilate CH₄ directly to the atmosphere, and surface water CH₄ concentrations in these reservoirs are generally quite low (0.0028–0.305 μM). Moreover, only in two small reservoirs substantial CH₄ accumulation occurred at depths shallower than the level where water is used for power generation and irrigation, and in the only case where measurements were made in the outflowing water, CH₄ concentrations were quite low. In conjunction with short periods of CH₄ accumulation and generally lower concentrations than previously assumed, our study implies that CH₄ emission from Indian reservoirs has been greatly overestimated.     

Biodiversity,ecohydrology, threat status and conservation priority of the freshwater fishes of river Gomti,a tributary of river Ganga (India)

Extensive surveys were conducted to explore the diversity of fishes, distribution patterns, abundance, threat, and habitat status in the upper, middle, and lower stretch of river Gomti, a tributary of river Ganga. Altogether 56 fish species belonging to 20 families and 42 genera were collected from various sampling sites. Of the 56 species, five belong to the ‘endangered’ (EN) category and 11 belong to the vulnerable (VU) category. Six major categories of habitat were identified and pattern of fish assemblage and dominant genera in each habitat studied. Considerable differences were observed in the fish species richness and relative abundance (RA) of the species in the different sampling sites of river Gomti. Shannon–Wiener biodiversity index has been calculated for the fishes indicating considerable variation (p < 0.05) across the river. Apart from Indian Major Carps (Labeo rohita, Catla catla, Cirrhinus mrigala), Chitala chitala, Notopterus notopterus, Ompok pabda, O. bimaculatus, Labeo bata, L. calbasu, Cirrhinus reba, Channa marulius, Bagarius bagarius, and Clupisoma garua were the important species. All the species have been reported for the first time in this river. Indiscriminate catch, poisoning, using of fine mesh sized nets, dumping of sewage, siltation, water abstraction, changing land use pattern, decreased water discharge, and exotic species threaten the fish diversity. Urgent need exists for taking up research on the priority fish species and their habitat. Restoration measures have been proposed based on ecosystem scale approach for fish biodiversity conservation.     

The recent occurrence of exotic freshwater fishes in the tributaries of river Ganga basin: abundance, distribution, risk, and conservation issues

We record here the recent occurrence, abundance and distribution of six exotic fish species, viz. Oreochromis mossambicus, Cyprinus carpio, Hypopthalmicthys molitrix, Ctenopharyngodon idellus, Clarias gariepinus, and Pterygoplichthys disjunctivus (a new exotic in India) distributed through the four important tributaries of river Ganga basin in India. From the total catch, the abundance index of all exotic species in different rivers ranged from 1.1 to 14.5?% with highest value in River Gomti. The relative abundance of the exotic species in all the four tributaries demonstrated that a single species C. carpio contributed a considerable abundance (43.3?C83?%) than that of the remaining exotic fishes. The Common Carp, C. carpio, was ubiquitous in all the four tributaries of Ganges basin studied and had the highest local distribution (52.63?%). Smaller size groups of endangered (Chagunius chagunio, Chitala chitala, and Tor tor) and migratory species (Bagarius bagarius, Ompok pabda, Wallago attu, and Sperata aor) in the four tributaries were recorded, and the increasing appearance of Common Carp and other exotic fishes is signaling biological invasion. Possible threats to the indigenous fish fauna, as a result of the invasion and proliferation of these exotics, are discussed.     

Assessment of habitat quality with relation to fish assemblages in an impacted river of the Ganges basin, northern India

In this work, we examined water-quality assessment in relation to fish assemblage of Gomti River, a large tributary of the Ganges River basin in northern India. Principal component analysis was performed for 18 environmental variables which produced three axes that cumulatively explained 60.23% of the environmental variation in sites. Fifteen variables (fine substrate fine gravel, coarse gravel, cobble, sand substrate water flow, conductivity, TDS, total hardness, temperature, dissolved oxygen, pH, and overhanging vegetation) had high loadings on at least one of the principal component axes interpreted. The canonical correspondence analysis was used to establish the relationship between important fish species and environmental variables. Species were distributed within four groups with respect to the significant habitat characteristics. The Pearson correlation coefficient was calculated between the water-quality parameters. We concluded that the level of species richness is mostly dependent on abiotic factors like temperature, dissolved oxygen, TDS, conductivity, depth, pH, and water current in the Gomti River, of the Ganges basin.     

Seasonal variation in physicochemical properties of coastal waters of Kalpakkam, east coast of India with special emphasis on nutrients

A study pertaining to the seasonal variation in physicochemical properties of the coastal waters was carried out at Kalpakkam coast for a period of 1 year (February 2006 to January 2007). It revealed that the coastal water was significantly influenced by freshwater input during North East (NE) monsoon and post-monsoon periods. Concentration of all the nutrients and dissolved oxygen (DO) was relatively high during the NE monsoon, whereas, salinity and chlorophyll-a (chl-a) were at their minimum level during this period. Phytoplankton production peak was observed in summer during which a typical marine condition prevailed. The present observed values of nitrate, phosphate, silicate, and turbidity are significantly high (five to ten times) compared to that of the pre-Tsunami period from this coast. Relatively low DO and chl-a concentration was noticed during the post-Tsunami period. A notable feature of this study is that though nutrient concentration in the coastal waters during post-Tsunami period has increased significantly, turbidity, the most single dominating factor, was found to adversely affect the phytoplankton production during post-Tsunami period as reflected by relatively low chl-a concentration. Thus, the post-Tsunami period may result in a change in coastal biodiversity pattern concomitant with change in coastal water quality.