Real-time monitoring of air pollutants in seven cities of North India during crop residue burning and their relationship with meteorology and transboundary movement of air.

Air pollutants emissions due to the burning of crop residues could adversely affect human health, environment, and climate. Hence, a multicity campaign was conducted during crop residue burning period in Indo Gangetic Plains (IGP) to study the impact on ambient air quality. Seventeen air pollutants along with five meteorological parameters, were measured using state of the art continuous air quality monitors. The average concentration of PM10, PM2.5, and PM1 during the whole campaign were 196.7±30.6, 148.2±20, and 51.2±8.9 µgm-3 and daily average concentration were found several times higher than national ambient air quality standards for 24h. Amritsar had the highest average concentration of PM2.5 (178.4±83.8 µgm-3) followed by Rohtak and Sonipat (158.4±79.8, 156.5±105.3µgm-3), whereas Chandigarh recorded the lowest concentration (112.3±6.9µgm-3). The concentration of gaseous pollutants NO, NO2, NOx, and SO2 were also observed highest at Amritsar location, i.e., 6.6±2.6ppb, 6.2±0.7ppb, 12.7±3.0ppb, and 7.5±3.3ppb respectively. The highest average O3 and CO were 22.5±19.3ppb and 1.5±1.2ppm during the campaign. The level of gaseous pollutants and Volatile organic compounds (VOCs) found to be elevated during the campaign, which can play an important role in the formation of secondary air pollutants. The correlation of meteorology and air pollutants was also studied, and O3 shows a significant relation with temperature and UV (R=0.87 and 0.74) whereas VOCs shows a significant correlation with temperature (R=-0.21 to -0.47). Air quality data was also analyzed to identify sources of emissions using principal component analysis, and it identifies biomass burning and vehicular activities as major sources of air pollution.

Assessment of aerosols optical properties and radiative forcing over an Urban site in North-Western India.

The present work is aimed to analyze aerosols optical properties and to estimate aerosol radiative forcing (ARF) from January to December 2013, using sky radiometer data over Rohtak, an urban site in North-Western India. The results reveal strong wavelength dependency of aerosol optical depth (AOD), with high values of AOD at shorter wavelengths and lower values at longer wavelength during the study period. The highest AOD values of 1.07 ± 0.45 at 500 nm were observed during July. A significant decline in Ångström exponent was observed during April-May, which represents the dominance of coarse mode particles due to dust-raising convective activities. Aerosols' size distribution exhibits a bimodal structure with fine mode particles around 0.17 µm and coarse mode particles with a radius around 5.28 µm. Single scattering albedo values were lowest during November-December at all wavelengths, ranging from 0.87 to 0.76, which corresponds to the higher absorption during this period. Aerosols optical properties retrieved during observation period are used as input for SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) to estimate the direct ARF at the surface, in the atmosphere and at the top of the atmosphere (TOA). The ARF at the TOA, surface and in the atmosphere are found to be in the range of -4.98 to -19.35 W m-2, -8.01 to -57.66 W m-2 and +3.02 to +41.64 W m-2, respectively. The averaged forcing for the whole period of observations at the TOA is -11.26 W m-2, while at the surface it is -38.64 W m-2, leading to atmospheric forcing of 27.38 W m-2. The highest (1.168 K day-1) values of heating rate was estimated during November, whereas the lowest value (0.084 K day-1) was estimated for the February.

Physiological studies of native cyanobacterial species Lyngbya contorta and Phormidium foveolarum in sewage waste water.

A variety of Cyanobacterial species predominantly ensheathed forms occurs in sewage water receiving areas. A study was conducted to analyse the potential of using native Lyngbya contorta and Phormidium foveolarum isolated from sewage water irrigated soils, for biomass production under sewage waste water. The native Cyanobacterial strains were characterised and changes in their biochemical composition in response to different concentrations of sewage waste water were investigated. Results showed that biomass(3.5-6.6 mg 10 ml⁻¹, 2.6-5.6 mg 10 ml⁻¹) and photosynthetic pigment contents increased with incubation time (chlorophyll 1.21-3.09 µg ml⁻¹, 1.92-9.51 µg ml⁻¹; carotenoid 20.8-34.8 µg ml⁻¹, 16.4-32.8 µg ml⁻¹) and decreased thereafter as nutrients became limiting. On the other hand, soluble proteins, after showing a decline, recovered faster with maximum concentration (42.6-63.3 µg ml⁻¹ and 59-79.8 µg ml⁻¹) recorded on day 8. Total carbohydrate content also increased (19.27-31.45 µg ml⁻¹, 14.1-28.21 µg ml⁻¹) in response to various concentrations of sewage waste water. The overall response was better for 50% sewage waste water concentration which showed that these native strains were suitable candidates for cultivation after proper dilution.

Fungal biosorption--an alternative to meet the challenges of heavy metal pollution in aqueous solutions.

The removal of heavy metal from the environment, especially wastewater, is now shifting from the use of conventional methods to the use of biosorption, which may be defined as the binding and concentration of selected heavy metal ions or other molecules on to certain biological material. Although most biosorption research concerns metal and related pollutants, including radionuclides, the term is now applied for particulates and all manner of organic pollutants as well. Such pollutants can be in gaseous, soluble and insoluble forms. Biosorption is a physical process carried out through mechanisms such as ion exchange, surface complexation and precipitation. It is a property of both living and dead organisms (and their components) and has been heralded as a promising biotechnology for pollutant removal from solution. Various biomasses such as plant products (tree bark, peanut skin, sawdust, plant weeds etc.) have been tested for metal biosorption with very encouraging results. In this comprehensive review, biosorptive ability of fungal biomass toward heavy metals is emphasized. A detailed description of adsorption properties and mode of action of fungal biosorbents is offered in order to explain the heavy metal selectivity displayed by these biosorbents. The cell structure and cell wall of the fungal cell is evaluated in terms of metal sequestration. The parameters influencing the passive uptake of pollutants are analysed. The binding mechanism is discussed, including the key functional groups involved in the process. Quantification of metal-biomass interactions is fundamental to evaluation of potential implementation strategies; hence sorption isotherms and sorption kinetics, as well as models used to characterize fungal biosorbent sorption, are reviewed. Despite the continuing dramatic increase in published research on biosorption, there has been little or no exploitation in an industrial context. Thus, the current status and future directions regarding biosorption at an industrial level are discussed. A systematic comparative review of the literature, based on the metal-binding capacity of fungal biomass under different conditions, is also provided. The problems associated with fungal biosorption are analysed and suitable remedies are discussed. Thus, this article reviews the achievements and current status of fungal biosorption technology and hopes to provide insights into future research.

Assessment of heavy metal tolerance in native plant species from soils contaminated with electroplating effluent.

Heavy metals concentrations of (Cr, Zn, Fe, Cu and Ni) were determined in plants and soils contaminated with electroplating industrial effluent. The ranges of total soil Cr, Zn, Fe, Cu and Ni concentrations were found to be 1443-3240, 1376-3112, 683-2228, 263-374 and 234-335 mg kg⁻¹, respectively. Metal accumulation, along with hyperaccumulative characteristics of the screened plants was investigated. Present study highlighted that metal accumulation in different plants varied with species, tissues and metals. Only one plant (Amaranthus viridis) accumulated Fe concentrations over 1000 mg kg⁻¹. On the basis of TF, eight plant species for Zn and Fe, three plant species for Cu and two plant species for Ni, could be used in phytoextraction technology. Although BAF of all plant species was lesser than one, these species exhibited high metal adaptability and could be considered as potential hyperaccumulators. Phytoremediation potential of these plants can be used to remediate metal contaminated soils, though further investigation is still needed.