Remediation of noxious pollutants using nano-titania-based photocatalytic construction materials: a review

Environmental Science and Pollution Research - Nano-titania (n-TiO2), due to its unique photocatalytic and hydrophobic properties, can be used to prepare self-cleaning cement-based smart building...     

A Strategic Project Appraisal framework for ecologically sustainable urban infrastructure

Actors in the built environment are progressively considering environmental and social issues alongside functional and economic aspects of development projects. Infrastructure projects represent major investment and construction initiatives with attendant environmental, economic and societal impacts across multiple scales. To date, while sustainability strategies and frameworks have focused on wider national aspirations and strategic objectives, they are noticeably weak in addressing micro-level integrated decision making in the built environment, particularly for infrastructure projects. The proposed approach of this paper is based on the principal that early intervention is the most cost-effective and efficient means of mitigating the environmental effects of development projects, particularly macro infrastructure developments. A strategic overview of the various project alternatives, taking account for stakeholder and expert input, could effectively reduce project impacts/risks at low cost to the project developers but provide significant benefit to wider communities, including communities of future stakeholders. This paper is the first exploratory step in developing a more systematic framework for evaluating strategic alternatives for major metropolitan infrastructure projects, based on key sustainability principles. The developed Strategic Project Appraisal (SPA) framework, grounded in the theory of Strategic Environmental Assessment (SEA), provides a means of practically appraising project impacts and alternatives in terms of quantified ecological limits; addresses the neglected topic of metropolitan infrastructure as a means of delivering sustainability outcomes in the urban context and more broadly, seeks to open a debate on the potential for SEA methodology to be more extensively applied to address sustainability challenges in the built environment. Practically applied and timed appropriately, the SPA framework can enable better decision-making and more efficient resource allocation ensuring low impact infrastructure development.     

Shoreline change analysis of Vedaranyam coast, Tamil Nadu, India

The coastal zone is one of the nation’s greatest environmental and economic assets. The present research aims at studying the shoreline changes along Vedaranyam coast using conventional and modern techniques including field sampling, remote sensing, and geographical information system (GIS). The study area was divided into three zones. Dynamic Land/Sea polygon analysis was performed to obtain the shore line changes at different time periods between 1930 and 2005. From the multidate shoreline maps, the rate of shoreline change was computed using linear regression rate and end point rate. Further, the shoreline was classified into eroding, accreting, and stable regions through GIS analysis. The eroding, accreting, and stable coastal stretch along Vedaranyam is observed as 18 %, 80.5 %, and 1.5 %, respectively. Net shoreline movement is seaward, i.e., the coast is progressive with an average rate of 5 m/year. A maximum shoreline displacement of 1.3 km towards the sea is observed near Point Calimere. During the Asian Tsunami 2004, the eastern part of the study area showed high erosion. Sediment transport paths derived from the grain size analysis of beach sediments collected during different seasons help to identify the major sediment source and sinks. Point Calimere acts as the major sink for sediments whereas Agastiyampalli and Kodiakkarai are found to be the major sources for the sediment supply along the Vedaranyam coast. Shoreline change study from field and satellite data using GIS analysis confirms that Vedaranyam coast is accreting in nature.     

Duckweeds for water remediation and toxicity testing

The presence of toxic substances in wastewaters and outdoor bodies of water is an important ecotoxicological issue. The aim of this review is to illustrate how duckweeds, which are small, simply constructed, floating aquatic plants, are well suited to addressing this concern. The ability of duckweeds to grow rapidly on nutrient-rich water and to facilitate the removal of many substances from aqueous solution comprises the potential of these macrophytes for the remediation of wastewater and polluted aqueous reservoirs, while producing usable biomass containing the unwanted substances having been taken up. Their ease of cultivation under controlled and even sterile conditions makes duckweeds excellent test organisms for determining the toxicity of water contaminants, and duckweeds are important as model aquatic plants in the assessment of ecotoxicity. Duckweeds are also valuable for establishing biomarkers for the toxic effects of water contaminants on aquatic higher plants, but the current usefulness of duckweed biomarkers for identifying toxicants is limited. The recent sequencing of a duckweed genome holds the promise of combining the determination of water contaminant toxicity with toxicant diagnostics by means of gene expression profiling via DNA microarrays.     

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

Water pollution by pharmaceutically active compounds is an emerging issue. Toxicological studies reveal that pharmaceuticals are indeed toxic for living organisms. The lack of suitable treatment technology for the complete removal of pharmaceuticals is therefore a major challenge. Advanced oxidation processes are emerging removal techniques that have many advantages versus conventional technologies. Many studies indicate that advanced oxidation processes, either in single or in combination with other degradation techniques, can enhance the degradation of pharmaceuticals in aqueous solutions. Here, we review the degradation of pharmaceuticals by sonolysis, an oxidation processes using ultrasound. In this technique, hydroxyl radicals are generated by pyrolytic cleavage of water molecules. We review the influence of operational parameters, additives and hybrid techniques on the degradation of pharmaceuticals. The maximum degradation of organic compounds was observed in the frequency range of 100–1000 kHz, which is in the high-frequency medium-power ultrasound. Even though almost all the experiments presented more than 90 % removal and good biodegradability of the target compound, good mineralization and the toxicity removal were hardly achieved. The efficiency of the degradation varies with water matrixes and varying pH. Major pathways of degradation are hydroxylation, dehalogenation, demethylation, decarboxylation, deamination, etc. More hybrid techniques have to be developed to scale up the application of ultrasound.     

Large-scale green synthesis of Cu nanoparticles

This article reports a novel, eco-friendly herbal method to synthesize Cu nanoparticles in large scales. Cu nanoparticles are an alternative to Ag and Au nanoparticles and have potential applications in many industrial areas. Many synthetic routes have been documented for the preparation of copper nanoparticles, but very few routes are eco-friendly and large-scale. We report here the preparation of Cu nanoparticles from aqueous CuSO₄ using non-toxic and inexpensive materials like curd, milk, and herbal extracts such as tamarind and lemon juice as capping agents. X-ray diffraction and transmission electron microscopy show that produced particles are nanocrystalline copper 20–50 nm in size with a face-centered cubic structure. Fourier-transformed infrared spectroscopy evidences the role of organic acids in the capping process. The novelty of this work is the synthesis of Cu nanoparticles from CuSO₄ without electricity and using non-toxic, cheap capping agents.     

The potential impacts of sea level rise along the coastal zone of Kanyakumari District in Tamilnadu,India

Climate change associated with sea level rise (SLR) is one of the major environmental concerns of today. This paper presents an assessment of the impacts of sea level rise on the coastal zone of Kanyakumari District in Tamilnadu, India. Digital Elevation Model (DEM) combined with overlay techniques in GIS are used in determining the inundation zones along the coastal region. The analysis evaluated the impact on coastal fishing villages, landuse, tourist spots and sensitive areas under threat. The vulnerability of the coastal areas in Kanyakumari to inundation was quantified, based on the projected sea level rise scenarios of 0.5 and 1 m. Our findings reveal that approximately 13 km² of the land area of Kanyakumari would be permanently inundated due to SLR. This would result in loss of land, alteration of the coastal zone and affects coastal ecosystem. From the study, the mitigation measures (engineering measures) and Coastal Zone Management practices that can be taken to protect human life and property from sea level rise are suggested.     

Estimation of microplastics in sediments at the southernmost coast of India (Kanyakumari)

Environmental Science and Pollution Research - Increasing urbanization and anthropogenic activities of the last couple of decades have left significant amounts of plastic debris in both coastal and...     

Evaluation of air pollution phytotoxicity in a seasonally dry tropical urban environment

This study was conducted in the urban environment of Varanasi, India, to evaluate the plant responses to urban air pollution. Twenty sites were selected in four different zones of the city. At each site, seven woody perennials of same age classes were selected. Out of the four zones (I, II, III and IV), zone IV was used as a reference (control) zone as it received the minimum pollution input. Plant species growing in polluted and control areas were compared with respect to foliar dust load, per cent leaf area injury, leaf area, specific leaf weight and chlorophyll, ascorbic acid, SO ₄ ^2– S and total N concentration in the leaves. Results indicated that the air pollution level in Varanasi causes leaf damage, reduces leaf area, specific leaf weight and chlorophyll, ascorbic acid and total N concentrations in the leaves. Sulphur concentration in leaves increased with increasing level of SO₂ in the ambient air. The magnitude of such changes was maximum at the zone receiving maximum pollution load. Carissa carandas was found to be the most sensitive species and Bougainvillea spectabilis, the least. The study shows that the urban air pollution level in Varanasi is detrimental for the growth of plants involved in this study.     

An anticlastogenic in vivo micronucleus assay for tea

Common use of antimutagens and anticarcinogens in everyday life is an effective measure for preventing human cancer and genetic diseases. Antioxidant properties of tea have vast potential as protective agents against diverse toxic effects. The present study was aimed to evaluate the role of aqueous clonal tea extracts (green tea, oolong tea and black tea) in modulating the genotoxic damage induced by cyclophosphamide (CP), a commonly used chemotherapeutic drug and a well-known mutagen and clastogen. All the three tea extracts at 1 and 2% concentration did not increase the frequency of micronucleated polychromatic erythrocytes (MPE) in bone marrow cells of mice when administered individually. The tea extracts decreased the micronuclei (MN) induced by CP. Therefore, regular intake of tea may improve the antioxidant status in in vivo and thereby reduce the risk of cancer and coronary heart disease.