The spatial-temporal distribution of air pollutants over India’s growing cities is still uncertain due to the lack of monitoring data and inadequate knowledge. This study analyzes the temporal and spatial trends of particulate matter in Coimbatore and furthers the influence of urban growth on aerosol concentrations also investigated. The average concentration of PM2.5 and PM10 was 42.23 and 68.05 µg m-3 during the study period and slightly higher than the National Ambient Air Quality Standards. Aerosol concentrations were found to be highest in an industrial site (81.17 µg m-3 for PM10 and 51.89 µg m-3 for PM2.5), medium in urbanindustrial (69.09 µg m-3 for PM10 and 42.53 µg m-3 for PM2.5), commercial (69.99 µg m-3 for PM10 and 42.31 µg m-3 for PM2.5), residential (68.39 µg m-3 for PM10 and 41.21 µg m-3 for PM2.5) sites, and low in the mixed site (51.59 µg m-3 for PM10 and 33.19 µg m-3 for PM2.5). Geographic Information System analysis results indicate that Coimbatore city became more urbanized and more polluted than before. PM2.5/PM10 ratio of 0.60-0.65 in the respective locations revealed the dominance of PM2.5. Vehicular exhaust emissions and road dust resuspension are the primary sources of air quality deterioration in Coimbatore city since there are no other significant pollution sources. Our findings provide baseline information concerning the influence of urbanization and transportation on particulate matter pollution in Coimbatore city.

In this study, we investigate the impact of the COVID- 19 pandemic on PM2 5 levels in the national capital city Delhi, India PM2 5 and meteorological data from 35 ground-based monitoring stations over Delhi city are utilized for the present study Geographic Information System-based spatial interpolation method was employed to analyse the spatial pattern of PM2 5 from January to April 2020 and compared with that of preceding years (2018–19) The findings indicate that the PM2 5 level has reduced significantly during the lockdown period About 40% of reduction in PM2 5 concentrations is observed when compared to the prelockdown phase Exclusively between 25 March and 30 April, about 94 44% of days were within the NAAQS 24-h standard limit of 60 μg/m³ The significant role of meteorology in the dispersal of PM2 5 over Delhi is clear from the correlation analysis A strong negative correlation (r = –0 546) between the Temp and PM2 5 indicates the better dispersion of air pollutants during high-temperature conditions A higher reduction in PM2 5 has been observed in Central, Northern and Eastern parts of the megacity The present study provides insights to policymakers to prepare and implement future policy measures for controlling air pollution levels in the megacity [ABSTRACT FROM AUTHOR] Copyright of Current Science (00113891) is the property of Indian Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission However, users may print, download, or email articles for individual use This abstract may be abridged No warranty is given about the accuracy of the copy Users should refer to the original published version of the material for the full abstract (Copyright applies to all Abstracts )

Recent studies concluded that air quality has improved due to the enforcement of lockdown in the wake of COVID-19. However, they mostly concentrated on the changes during the lockdown period, and the studies considering the consequences of de-escalation of lockdown are inadequate. Therefore, we investigated the changes in fine particulate matter (PM2.5) during the pre-lockdown, strict lockdown, unlocking, and post-lockdown scenarios. In addition, we assessed the influence of meteorology, mobility, air mass transport, and biomass burning on PM2.5 using Google's mobility data, back trajectory model, and satellite-based fire incident data. Average PM2.5 concentrations in Ghaziabad, Noida, and Faridabad decreased by 60.70%, 63.27%, and 60.40%, respectively, during the lockdown. When compared with the preceding year (2019), the reductions during the shutdown period (25 March–31 May) were within the range of 36.34–44.55%. However, considering the entire year, this reduction in PM2.5 is momentary, and a steady increase in traffic density and industrial operations within cities during post-lockdown reflects a potent recovery of aerosol level, during which the average mass of PM2.5 three- to four-folds higher than the lockdown period. Back trajectories and fire activity results showed that biomass burning in the nearby states (Haryana and Punjab) influence aerosol load. We conclude that a partial lockdown in the event of a sudden surge in pollution would be a beneficial approach. However, reducing fossil fuel consumption and switching to more environmentally friendly energy sources, developing green transport networks, and circumventing biomass burning are efficient ways to improve air quality in the long term.

Contamination of freshwater sediments by chromium (Cr) is a worldwide problem stemming from numerous natural anthropogenic activities in the industrial, domestic, and agricultural sectors. Determination of total Cr concentration in sediment does not provide useful information about its mobility, bioavailability, and toxicity. It is generally accepted that partitioning of Cr into fractions in sediments can provide essential information such as metal mobility, bioavailability, and environmental and human health risks. In this context, the investigation presented in this chapter focused on Cr fractionation and its possible implications on the costal environment on the southeast coast of India. A total of forty surface sediments were collected during wet and dry seasons to represent varying land uses, and point and nonpoint source pollution in the upstream, midstream, and downstream regions. In this study, Cr content in sediment is fractionated into five fractions; namely, exchangeable, carbonate bound, FeMn oxide bound, organic bound, and residual using a five-stage sequential extraction scheme developed by Tessier et al. (1979). The results revealed that the order of Cr fraction in terms of concentration was found to be: residual (F5) > organic bound (F4) > Fe–Mn oxide bound (F3) > carbonate bound (F2) > exchangeable (F1). A risk assessment code was applied to find out the polluted sites, which revealed that sediment samples of the upper delta regions fall under the low risk category, while 70%–95% of samples in the estuarine regions fall in a medium risk category, both in dry and wet seasons. According to the assessment of mobility factor, maximum levels of mobile chromium (45.6%) were recorded at Nagore (coastal region), raising concern for aquatic biota and humanity in that region. The order of mobility was observed as: estuarine region > mid delta > upper delta. The present study also revealed that the fractionation studies can be used for assessing the extent of Cr mobility in river sediments and its associated risk to the coastal biota.

The increasing prevalence of antibiotics in the environment has promoted the development of antibiotic resistant microorganisms, and novel approaches are needed to effectively remove antibiotics from water and mitigate this worldwide problem. A reduced graphene oxide‐V2O5 (RGOV) nanocomposite was synthesized and used for photocatalytic degradation of the antibiotic oxytetracycline (OTC) in aqueous solution. The Sol–Gel method was employed for V2O5 synthesis from e‐waste‐based vanadium nitrate, and a one pot solvothermal method was used to synthesize RGOV. Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) with energy dispersive analysis of X‐rays (EDAX) confirmed V‐O‐C bonds on the surface of the RGOV nanocomposites. A decrease in the band gap of V2O5 from 2.21 to 2.13 eV was supported by diffuse reflectance ultraviolet–visible spectrophotometry. OTC adsorption onto the nanocomposite increased with an increase in RGO concentration and saturated at 17% for RGOV with 30% graphene oxide. The composite degraded 90% of the OTC present in aqueous solution (50 mg/L). Platinum (1%) doping further increased OTC degradation by the nanocomposite to 98.7%. Optimum conditions for maximum OTC degradation are (1) an initial OTC concentration of 50 mg/L, (2) a RGOV nanocomposite dose of 0.5 g/L, and (3) a 40 min incubation time. Our results support the potential use of RGOV nanocomposite for OTC photodegradation. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13123, 2019

The main objective of this study is to focus on the removal of colour and chemical oxygen demand (COD) from the secondary treated effluent (SE) and reverse osmosis (RO) concentrate, using Fenton oxidation as an advanced oxidation process. In order to identify the feasibility and economics, the experiments were conducted in these two streams of the textilebased effluent treatment plant. In this study, COD and colour removal efficiencies were observed as 75% and 94% in the SE and 85% and 99% in the RO concentrate respectively. After comparing the operating cost between these two streams, treating of SE with Fenton oxidation was found to be an economical, sustainable option for removing the colour and COD from the SE. This option will improve the performance of membrane filtration systems in effluent treatment plants that are based on zero liquid discharge.

Surface and groundwater samples were collected from the Stanley reservoir and its vicinity for two seasons (pre-monsoon and monsoon) and analyzed for physico-chemical characteristics. Variations between surface and groundwater and between pre monsoon and monsoon samples could be discerned through the studied parameters, signifying the roles of rainfall, and solute processes. Superimposed on these natural phenomena, elevated levels of chemical oxygen demand and biological oxygen demand indicative of high organic load in surface water and higher Cl and F contents in surface and groundwater as a result of anthropogenic inputs were observed. These results signify that, despite the dilutions from rainfall and potential percolation from large reservoir, the anthropogenic perturbations, mainly emanating from point and non-point sources contaminate the surface and groundwater resources.

Though traditionally considered to be less vulnerable to pollution than surface water, the groundwater resources face multiple sources of contamination during the recent times. In this paper, we employed modified SINTACS (Normal and Severe) model over a region known for thick clusters of leather processing industries, and dependence of domestic and industrial water supply on groundwater resources. Several parameters including, depth to groundwater, effective infiltration, unsaturated zone attenuation capacity, soil attenuation capacity, hydrogeological characteristics of the aquifer, hydraulic conductivity and topographical slope were spatially evaluated and subjected to overlay analysis after assigning appropriate ratings and weights to identify the different vulnerability levels in the study area. The results show that, the groundwater vulnerability to pollution is very high on the eastern part of the study area, under the influences of gentle slope, alluvial soil and higher permeability. In addition, scattered occurrences of vulnerable zones aligned along the river course are also identified.

Phosphorus is both a nutrient and a key factor responsible for eutrophication of freshwater ecosystem. Knowledge on geochemical forms of phosphorous is one among the proxies to monitor the quality of an aquatic ecosystem. Channel-bed sediment samples were collected from the Cauvery River in delta region, fractionated into five namely, exchangeable P, Fe-P, Al-P, Ca-P and Residual-P and were studied. Total phosphorous concentration of ranged between 360 and 1,070 mg/kg. The mean values of P fractions are: HCl-P (68 %), NaOH-P (12 %) and NH4Cl-P (8 %). Among the phosphorous fractions studied, HCl extractable P recorded as a dominating chemical form. It implies P had a preferential association with Ca. The pH of the river sediments varied from 7.37 to 8.69 implying alkaline nature. Total Organic Carbon (TOC) and Organic Matter (OM) of the sediments showed ranges of 0.04–1.0 % and 0.14–3.45 %, respectively. Total Nitrogen (TN) of the sediment samples was in the range between 0.08 and 0.20 %. The C/P and N/P ratios ranged 1.65–78.67 and 1.33–6.69, respectively.

Mettur an industrial town is located in Salem district of Tamil Nadu, India.The major industries, namely; Chemplast, The Madras Aluminum Company and Mettur Thermal Power Plant are located in Mettur town.In addition, several chemical industries are situated on the banks of the River Cauvery as part of Small Industries Development Corporation (SIDCO) industrial estate.With this background, the present study attempts to investigate the usefulness of multivariate statistical analysis for the assessment of complex data sets to get better information about an influence of various parameters on groundwater chemistry and heavy metal concentrations.Groundwater samples were collected during pre-monsoon (June 2013) and post-monsoon (February 2014) seasons and analysed for heavy metals and other hydro chemical characteristics.The results of the multivariate statistical analysis show that the sampling site have different characteristics in terms of heavy metals studied and indicate that each region receives pollution from different sources.The high level of some of the heavy metals and hydrochemical recorded in certain pollution packets ultimately implies an alarming situation in the viewpoint of health risk.The notable differences in the quality of groundwater between the sampling sites indicate possible land use influences.

Chemical partitioning of heavy metals (Fe, Mn, Cu, Cr, Pb, Zn, Ni) were determined in surface sediments of three reservoirs at the Delta region of Cauvery River, India. The abundance of metals in sediments varied in the following descending order: Fe, Mn, Cr, Zn, Cu, Ni, and Pb. Higher concentrations of Zn, Pb, Fe, Mn and Cu in exchangeable and carbonate fraction indicated toxicity risk to the biota. Therefore, to understand the extent of bioaccumulation, six commercial fish species were collected from the same sites and analyzed for heavy metals distribution in different organs. Among the metals found in fish samples, iron was observed in the highest concentration, followed by Zn, Pb, Cr, Mn, Cu, and Ni. Concentrations of Pb, Cr and Zn in many fish samples exceeded the permissible limits of Food and Agriculture Organization. The concentrations of Pb (17.7–31.7%), Cr (6.2–15.1%), Cu (15.2-30.5%) and Zn (30–40%) associated with exchangeable and carbonate fractions had significant positive correlation with the respective metal concentrations in fish. Among the fish species, Catla catla and Etroplus suratensis showed the highest accumulation of metals suggesting risk for human consumption.

Geochemical fractionation of iron (Fe), manganese (Mn), copper (Cu), chromium (Cr), lead (Pb), zinc (Zn), and nickel (Ni) were determined using five-stage sequential extraction in sediments collected from estuarine stretches of Cauvery River delta on the eastern coast of India with emphasis on seasonal variation. Abundance of metals in terms of sum of total fractionations varied in the following order: Fe > Mn > Cr > Zn > Cu > Ni > Pb. Exchangeable fraction, believed to be bioavailable, showed differential abundances during the dry and wet seasons in the following order: Pb > Zn > Cu > Mn > Ni > Cr > Fe and Zn > Cu > Cr > Ni > Mn > Pb > Fe, respectively, indicating the possibility of anthropogenic influence. Among nonlithogenic fraction, organic matter–bound fraction is the second largest and a key scavenger for all of the heavy metals studied except Fe and Mn. A significant portion of Cu-associated organic matter fraction shows strong association of Cu with organic matter at most of the sampling sites. Environmental risk of metals evaluated using risk-assessment code and mobility factor showed low to high risk for Pb, Zn, and Cu. The results of the present study also hint at notable enrichment of heavy metals in the certain pockets of the Cauvery Estuary.

Coimbatore is one of the fast growing industrial cities of Southern India with an urban population of 1.9 million. This study attempts to evaluate the trends of airborne fine particulates (PM 2.5) and polyaromatic hydrocarbons (PAH) on them. The PM 2.5 mass was collected in polytetra fluoroethylene filters using fine particulate sampler at monthly intervals during March 2009 to February 2010. PAHs were extracted from PM 2.5 and estimated by high-performance liquid chromatography. It is alarming to note that PM 2.5 values ranged between 27.85 and 165.75 μg/m3and exceeded the air quality standards in many sampling events. The sum of 9 PAHs bound to PM 2.5 in a single sampling event ranged from 4.1 to 1632.3 ng/m3. PAH diagnostic ratios and principal component analysis results revealed vehicular emissions and diesel-powered generators as predominant sources of PAH in Coimbatore.

Groundwater is generally presumed to be good for human consumption and is used as a main source of drinking water. Although there are numerous reasons for groundwater pollution, anthropogenic sources are considered as the prime ones. In this study, twenty-two groundwater samples were collected from the flood plains of upper Palar River during the pre- and post-monsoon seasons to assess the extent of pollution and effects on human health. Physico-chemical characteristics of groundwater were analyzed and compared with those of drinking water standards recommended by the World Health Organization (WHO) and the Bureau of Indian Standards (BIS). The Piper's trilinear diagram shows the nature of alkali earth with the high contents of alkalies and prevailing sulphate in the present samples. The univariate statistics and correlation analysis were performed to find out the relationships between the variables. The tannery effluents, solid wastes and sewage were suspected to be the predominant sources of pollution in the area.

Urbanization and rapid growth of population in India has led to drastic increase in municipal solid waste. Unscientific disposal of municipal solid waste is one of the main reasons attributed for environmental degradation. The present work concentrates on municipal solid waste management in Tiruchirappalli City which comprises of four zones namely Srirangam, Goldenrock, Araiyamangalam and Abishekapuram. This study also attempted to assess the physical composition, characteristics and the heavy metals content in municipal solid waste. It can be observed that the bio-degradable fraction of municipal solid waste is found to be 74 percent of the total solid waste generated from the city. Hence composting could be the best option for the treatment of municipal solid waste.

Airborne PM 2.5 and polycyclic aromatic hydrocarbons (PAHs) bound to it were determined from March 2009 to February 2010 at different locations in Tiruchirappalli City, Southern India using fine particulate sampler and high performance liquid chromatography. Average ∑9 PAHs concentrations at four sampling stations were 333.7, 202.6, 265.9, and 232.7 ng/m(3), respectively. Highest concentration of PAHs was observed during northeast monsoon season (301.5 ng/m(3)) and lowest in southwest monsoon (216 ng/m(3)). Low and medium molecular weight PAHs such as phenanthrene, anthracene, benzo(a)anthracene and chrysene were observed in all seasons. Principal compound analysis revealed gasoline and diesel vehicular emissions as major sources for PAHs compounds.

The efficacy of tropical forest sinks in India continues to diminish in spite of several conservation efforts carried out at both governmental and non-governmental level. Lack of proper periodical and complete spatial inventory of carbon stock in India is a disturbing aspect at this aim. Carbon stock assessments are available only for few patches of Western Ghats of India, while assessment is almost negligible for Eastern Ghats. This paper focuses on estimation of existing carbon stock in the above ground biomass, litter, debris and soils (up to 30 cm) of different forest types of Kolli forest, located in Eastern Ghats of Tamilnadu, India (78°20’ to 78°30’E Long and 11°10’ to 11°30’ N Lat), within an area of 503 km2. Floristic diversity of Kolli hills is rich of endemisms and includes about 150 tree species. To estimate the carbon stock, about 26 quadrates of 25 X 25 m size were established. The organic carbon content of forest soil varied from 1.71 to 12.59%. The total carbon stock of soil, surface litter, coarse wood debris and total above ground biomass were estimated as 5.54, 0.034, 0.001 and 4.49 Tg C, respectively.

BACKGROUND:Airborne fine particulates (PM 2.5) and its associated polycyclic aromatic hydrocarbons (PAHs) are reportedly hazardous in urban environment due to the presence of multiple emission sources.METHODS:In this study, fine particulates collected from fourth largest metropolitan city of India, Chennai, were extracted and analyzed for 11 PAHs by high-performance liquid chromatography equipped with a fluorescence detector.RESULTS:PM 2.5 values varied between 27.2 and 190.2 μg/m(3), while average concentration of particle-associated PAHs determined was in the range from 325.7 to 790.8 ng/m(3), which signaled an alarming pollution level in Chennai.CONCLUSIONS:Factor analysis suggested vehicular emissions inclusive of petrol- and diesel-driven engines as probable sources.