- Ambient air quality management (AQM) and aerosol-induced climate effects
- Built environments and indoor air quality monitoring
- Monitoring and conserving earth resources through satellite imagery and field studies
CHEMICAL AND MICROBIAL ANALYSES
- Anion analyses
- Isotope analysis for understanding the chemodynamics of various species between the air, water and soil systems with brief descriptions of the utility of Cu and Hg isotopes
THEORY AND MODELING
- Aerosol dynamics
- Receptor models for air quality management
- Understanding the coupling between air-earth-water systems
- Metagenomics for bioremediation and assessment of water quality
- Development of molecular receptors for near real-time monitoring of relevant analytes in different environments
Ambient air quality management (AQM) and aerosol-induced climate effects
TIndia promulgated a revised National Ambient Air Quality Standards, NAAQS regulating fine particulate matter (fine PM, PM2.5) concentrations only as recently as 2009. Consequently there is a general lack of fine PM measurements in the country and very few studies examine the climate, air quality, and health effects of fine PM. However, recent studies over a few locations in India and elsewhere in the world show that fine PM plays a significant role in regulating and altering the earth’s radiative balance in addition to having detrimental health and visibility effects.
CREST will undertake field studies to sample PM2.5 and gaseous pollutants at several locations in Central India along with monitoring their optical properties and meteorological parameters. This activity is expected to significantly enhance our understanding of the sources of particulate pollutants over Central India, quantify the radiative forcing (climate effects) of such sources, and provide background information for future source apportionment and ambient aerosol induced plant/animal health effect studies.
Framework for field measurement with chemical analyses and modeling for understanding aerosol sources and radiative effects
Built environments and indoor air quality monitoring
Indoor air quality is increasingly recognized as more important that ambient air quality, since people spend over 95% of their indoors. CREST will gradually build the expertise to assess indoor air-quality in various built environments through field studies and application/ development of theoretical models. Indoor air-quality studies are proposed to be initially a collaborative activity. The members of the research team have existing collaborations with researchers in indoor air-quality management. Such collaborations will be strengthened to achieve CREST’s objectives.
Monitoring and conserving earth resources through satellite imagery and field studies
Long term and real-time monitoring of the earth resources through satellite imagery followed by field visit and active campaigning for the conservation of resources will serve as an important tool in conserving and protecting earth resources. Collaboration will be explored with ISRO for obtaining real time data. The real time data will be extremely important for modeling purpose as we can determine and quantify all of the real time variables from MP and adjoining areas.
Proper balance between earth-air-water mega systems components is essential to have the sustainable environment. Building of large dams and reservoirs seriously affects the ground water levels. As a result, in the summer, the bare land becomes vulnerable and easily eroded. The eroded material will get deposited in the reservoirs that reduce the capacity of the dam. Again, during the monsoon time, the reservoir is always over flooded due to reducing capacity. The water that flooded the adjoining lands will get contaminated with the pesticides and returned to the dam. This can be prevented by proper land use management around the reservoirs to increase reservoir’s sustainability. Similar approach can be taken in active mining areas where improper discharge of mine waste (acid-mine) contaminates the ground water. Processing of high resolution satellite imagery is the first step to identify the affected domains.
ASTER LIB data will be used for the present study. ASTER is a collection of sensors that can record radiations ranging from visible to thermal infrared wavelengths. The present dataset will be available from LPDDAC NASA and JAPAN SPACE AGENCY. Image Processing Software ENVI 3.5 and ERDAS 2013 will be used was used to process the data. The formula for different band-ratio images given below was originally developed for LANDSAT data. The equivalent representative bands of ASTER data are used here to obtain the same band images.
Normalized Difference Vegetation Index (NDVI) image is used widely to monitor the quality and distribution of vegetation. NDVI is computed using the formula:
d(band-3) -d (band-2)/d(band-3) +d (band-2)
Distribution and change of bare land play an important role in the land–water mega-system.
LANDSAT ETM+ images to calculate Normalized Difference Bareness Index (NDBI) is calculated in the following way:
d(band-5) -d (band-6)/d(band-5) +d (band-6)
These ratio images will be used to identify the domains with high bareness index with low water activity. In addition to the ratio images, Thermal Inertia image will be generated to identify the barren lands.
Anions are ubiquitous and play important roles in many biological, chemical, environmental and pathological processes. There is an increasing interest in the design and development of receptors that selectively recognize specific anions like phosphate, sulphate, fluoride, etc. For instance, considerable effort has been devoted to studies on fluoride ion (F-) receptors
because of its important role in dental care and clinical osteoporosis. Excess F- in the body can result in gastric and kidney disorders, dental and skeletal fluorosis, urolithiasis or can be fatal. CREST will focus of synthesizing and optimizing receptors for chemical characterization of anions that relevant from the perspective of environmental monitoring/protection.
Isotope analysis for understanding the chemodynamics of various species between the air, water and soil systems with brief descriptions of the utility of Cu and Hg isotopes
With the advent of the multiple-collector plasma-source mass spectrometry high precision measurements of isotopic variability of elements such as Fe, Zn, Cu, Si, Mg have become possible. Isotopic variations of Cu, Zn, Cd, and Hg has its application in environmental contexts to understand and constrain natural and anthropogenic sources and better understand contaminant cycling in the geobiosphere. Following the development of techniques for precise measurements of Cu, Zu and other such non-traditional isotopie by MC-ICPMS, these systems have found wide applications as geochemical tracers, paleo-oceanographic applications, ion-exchange mechanisms, and phase (metal/silicate/sulfide/vapor) separation.
Copper in ionic form is toxic even at very low concentrations yet it is essential for aerobic life as a complex and provides significant information about biogeochemical cycling. Stable isotope fractionation of copper can thus provide us with an important tool to investigate systematically the basic inorganic and biological chemistry of Cu. Little is known about the isotope composition of Cu in seawater. Studying the isotopic fractionation of copper during key steps in their geochemical cycling will allow us to use their isotope variations to probe changes in ocean chemistry through time. This study can be extended to Zn isotopes as well. Cu and Zn isotopes find wide applications in deciphering the history of supergene ore deposits, hydrothermal vent sulphides, nutrient budget of the ocean, tracing bacterial activity, lunar and planetary origin and so on.
Mercury is a unique metal, as it is volatile in elemental state at surface temperature and pressure and thus exists as a gas phase in the Earth’s atmosphere. Hg enters the atmosphere by evasion from water bodies, soil, and vegetation surfaces, through volcanoes, wild fires, and gaseous re-emission of previously deposited Hg. Gaseous Hg has a relatively long atmospheric residence time of 0.5-2 years, and therefore a bulk part of emitted elemental Hg enters the global Hg cycle. Evasion of gaseous mercury from waters and soils and its atmospheric deposition and redeposition are largely influenced by redox reactions. Hg in waters can be reduced photolyticly and by dissolved organic compounds. The environmentally significant species methyl mercury is produced by bacteria and perhaps by abiotic reduction. Methylmercury is not readily eliminated from organisms and thus biomagnifies with increasing trophic level from bacteria, to plankton, to herbivorous fish to piscivorous (fish- eating) fish.
In recent years studies have reported variations in the isotopic composition of mercury The causes of such variations were essentially unknown, but were interpreted to be mass-dependent fractionation. Mercury input in the environment is ever-increasing since industrial revolution. Coal fired power plant releases colossal amounts of mercury to the atmosphere, forest fires and prescribed controlled burns contributes ~ 25 percent of anthropogenic mercury emissions in US. Waste incinerators (specially medical wastes), chlor-alkali plants, metal smelting, refining and manufacturing etc adds significant amounts of inorganic mercury to the environment. The inorganic mercury is transformed to methyl mercury (MeHg) by sulfate reducing bacteria and bio-accumulates and bio-magnifies. During these processes mercury undergoes mass dependent and mass independent fractionation. The isotopes of mercury can be used as tracers to track its entire pathway specific to a particular environment. This has tremendous industrial significance as well, particularly in the fossil fuel industry.
Atmospheric aerosols are typically multi-component particles with complex chemical composition. Particles in the submicron size range consist mainly of sulphate, nitrate, ammonium, elemental carbon, primary and secondary organic matter and transition metals in the super-micron range, on the other hand, the main constituents are sea salt, nitrate, crustal materials, and primary organic matter. The relative contributions of different constituents in the particles are strongly dependent on their production mechanisms and the ambient conditions, and thus vary distinctively from site to site. The knowledge of the size distribution and composition of atmospheric aerosols is essential also to determine their effects on public health.
Computer modeling of aerosol dynamics is of importance in a wide spectrum of current applications, ranging from atmospheric chemistry, air quality studies and climate change, to a variety of technological fields. We propose to integrate the computer modeling of aerosol dynamics which is needed in several practical applications with the in-house experiments to study aerosol transport and deposition processes. Developing various physical and mathematical models of aerosol deposition in human lungs will also be an important part of the project which will be supported by the experimental studies.
Receptor models for air quality management
The fundamental principle of receptor modeling is that a mass balance analysis can be used to identify and apportion sources (Hopke 1985, 1991). The use of receptor models for air quality management is well tested and extensively discussed in literature. Factor analytic models have been used in receptor modeling for a long time, first based on the Principal Component Analysis (PCA) approach. Alternative models include Absolute Principal Components Analysis (APCA), Target Transformation Analysis (TTA), and Positive Matrix Factorization (PMF). Although all these methods suffer from rotational ambiguity, each method has its advantages and disadvantages. However, in combination with knowledge of likely sources and elemental profiles for different sources, these models can be used to make quantitative apportionment. Examples of results (obtained in the past) using PMF in conjunction with air parcel trajectory ensemble approaches and local meteorological data are shown below.
PMF resolved source profiles and contributions for aerosol measured over Hisar, Haryana (Sunder Raman et al., 2012)
PSCF map indicating potential source locations and preferred transport pathways of carbonate rich dust factor for Hisar aerosol (Sunder Raman et al., 2012)
CPF map indicating location of sources for combustion-rich aerosol factor for Hisar aerosol (Sunder Raman et al., 2012)
At CREST PMF will initially be used for ambient aerosol source apportionment. Additionally, several other approaches will be developed, tested, and used for air quality management.
Understanding the coupling between air-earth-water systems
The air-earth-water system has a great impact on the life cycle, and is a complex system. The study of sustainability development includes understanding the interaction between various components of this complex system. To simplify the study of this complex system, an approach is to view them as dynamical systems which are coupled to each other. The major advantage of this approach is that the problem becomes mathematical, and the techniques of dynamical systems – bifurcation analysis, ordinary differential equations, partial differential equations, numerical analysis, and control theory can be employed. These techniques have a substantial theoretical basis and allow us to very accurately predict the dynamics of the air-earth-water systems.
The converse approach is to develop models which behave like the air-earth-water system. Modeling of new mathematical structures using dynamical systems approach can help us understand the rapidly changing complex systems. The subsystems have their own parameters/characteristics such as time and space variables. Thus, an in-depth understanding of various subsystems and their interactions is essential, and dynamical systems approach is a valuable tool in this regard.
Metagenomics for bioremediation and assessment of water quality
Metagenomics has emerged as a powerful culture-independent approach for exploring the complexity and diversity of microbial genomes in their natural environments. It is now known that by using the traditional microbial identification and culturing approaches, 99% bacteria can not be identified. In this scenario, metagenomics provides a unique opportunity to access the genetic information inherent in diverse environments. The most apparent outcome of metagenomic projects is the identification of novel genomes, genes and biochemical pathways regardless of whether complete genome sequences can be assembled or not.
The metagenomic diversity of India is mostly unexplored. India, being a large and geographically diverse country, has several distinct environmental niches. Each of these environments harbors numerous unknown microbial species adapted to the conditions prevalent in that environment. In the past, we carried out the metagenomic analysis of the human gut of 13 healthy Japanese individuals, completed the first genome sequence of one of the most prominent un-culturable termite gut symbionts and the genome sequence of the uncultivable bacteria CfPt1-2 and unveiled its ability to fix dinitrogen. We are presently carrying out a few selected metagenomic projects including that of microbial fuel cell and environmental sediments. Taken together, it is apparent that metagenomics has emerged as a powerful approach for exploring the complexity and diversity of microbial genomes in their natural environments. It has revolutionized the genomic era and provides unique opportunities to study and monitor the environmental systems. It can potentially unlock the massive uncultured microbial diversity present in the environment for therapeutic, medical, environmental, agricultural and biotechnological applications. In the proposed project, I would like to explore how metagenomics can be used to assess the microbiome content of a fresh water body or a contaminated water body, and how this knowledge would help in the purification of water in a natural and environment friendly manner. I would be interested in developing strategies for bioremediation of areas where nuclear disasters have happened. Some of the major techniques which would be used are Next generation sequencing using Illumina HiSeq1500 and downstream computational analysis of the metagenomic data using in-house developed software and algorithms.
Main Steps for the estimation of bio-diversity
Main Steps for the metagenomic analysis of the selected environment
Bioremediation of nuclear waste using microbes
In the past a few bacterium, such as Deinococcus radiodurans, which can survive high doses of radiations had been accidentally discovered during food processing (1959) and sequenced a few years ago. This organism’s ability to repair extreme DNA damage (DNA broken into hundreds of pieces) caused by radiation, and survival has offered researchers many clues to the mechanisms of cellular repair. Similar to this organism, there may exist several other novel microbial species which could exhibit radiation-resistance properties. They might have developed novel DNA repair mechanisms and pathways to overcome the stress and damage done by these radiations. The identification of this novel microbial community, their genetic content and their novel DNA repair mechanisms would be significant in understanding mutagenesis and DNA repair. In addition, these microbes are suitable for bioremediation of the areas where a nuclear disaster has happened since they can survive in those regions and help in cleaning up of the waste.
There radioactive soil/sand of regions rich in natural radioactivity provides an appropriate sample for discovering radio-resistant microbes. The reported level of radiations (10,000-12000 μSv per year) in such regions seems to be strong enough to cause DNA mutagenesis in these microbial inhabitants. In general, the soil bacteria may not possess radio-resistance. Since the selected regions are one of the unique regions on earth having naturally radioactive soil for thousands of years, the microbial population in this region may have undergone natural selection process and evolved novel mechanisms for their survival in this region.
By using a metagenomic approach, we propose to carry out a comprehensive analysis of the bacterial diversity present in such regions. This study carried out to decipher the bacterial community of this region is likely to be highly revealing with many potentially interesting outcomes
Electrogenic microbes and their applications in waste-water management
Some microbes have a unique ability to use up the organic wastes for their metabolic activities and transfer their electron to an external electron acceptor which can be used for the production of electricity in microbial fuel cells. A few species of such bacteria have been discovered by us earlier. Presently, we are carrying out the metagenomic analysis of microbial fuel cells and would like to engineer some of the selected bacteria so that they can clean up the organic wastes in waste water plants and can also provide the necessary power for the operation of these plants.
Development of molecular receptors for near real-time monitoring of relevant analytes in different environments
Exploration and design of new functional materials with novel applications in the field of anion recognition is undergoing pronounced development from the past few decades. Even though anion- binding chemistry has emerged in recent years as one of the most intensely explored areas of supramolecular chemistry, scientists still rely upon systems based on inspiration from biological world like proteins where anion binding is mostly achieved by the help of neutral amide functions employing the hydrogen bonding from the -CO-NH- moiety. Usually, a synthetic receptor scaffold involves covalent linking of a marker fragment in the form of a fluorophore or chromophore for generating output signal. Any anion interaction is clearly marked with the appearance of fascinating colour or fluorescent emission from the designed molecular system. This signaling mechanism can reliably be used for near-real time monitoring of these analytes in the field samples of air, water and soil. One such framework developed at CREST is summarized below:
Monitoring and managing agricultural sodicity using molecular receptors
Detecting carbonate and bi-carbonate ions using molecular receptors