Tree seedling establishment in dry tropics: an urgent need of interaction studies

The current anthropogenic activities and climate change are increasingly becoming a growing global concern for dry tropical forests. Worldwide, these ecologically important forests have degraded considerably since the past few decades due to such factors. These factors have harmful consequences on the vegetation structure and diversity especially tree seedlings, which may further aggravate climate change. Generally, the vegetation recovery is very slow and unpredictable in the dry tropics due to complex interaction among tree seedling, site (particularly, soil) and climatic conditions. We inculcated that a better understanding of the behavior of individuals of different tree species at seedling stage in dry forests is of immense importance. It is increasingly being recognized for explaining and managing the future composition of plant communities under changing environmental conditions. In this regard, the multi-factorial interaction studies under various resource–disturbance combinations are needed in dry tropical ecosystems to understand the: (1) impact of relative variability in resources and disturbances on the responses of tree seedlings of native species and (2) how the later relates to distinct functional and life history traits of the individual tree species. Most importantly, such studies would improve our limited understanding of how variation (natural and man-made) in nutrient availability, under the influence of other local environmental factors (such as water, light, grass competition, herbivory, fire, allelopathy and enhanced CO₂ conditions), would affect the dynamics of dry tropical forest community. It may help in the proper management of these forests. Moreover, it may prove helpful in the current climate change scenario, as change in forest community dynamics may have consequences on soil C sequestration and CO₂ efflux at global scale.     

An Ecologically-Sustainable Surface Water Withdrawal Framework for Cropland Irrigation: A Case Study in Alabama

Agricultural production in the state of Alabama, USA, is mostly rain-fed, because of which it is vulnerable to drought during growing season. Since Alabama receives a significant portion of its annual precipitation during winter months, the goal of this study was to evaluate the feasibility of water withdrawal from streams during winter months for irrigation in the growing season. The Soil and Water Assessment Tool (SWAT) was used to estimate the quantity of water that can be sustainably withdrawn from streams during winter high flow periods. The model was successfully calibrated and validated for surface runoff, base flow, and total stream flow. The stream flows generated by the model at several locations within the watershed were then used to examine how much water can be sustainably withdrawn from streams of various orders (first, second and third). Although there was a considerable year-to-year variability in the amount of water that can be withdrawn, a 16-year average showed that first, second, and third order streams can irrigate about 11.6, 10.3, and 10.6% of their drainage areas, respectively. The percentage of drainage area that can be irrigated was not a function of stream order.     

An overview of an indoor radon study carried out in dwellings in India and Bangladesh during the last decade using solid state nuclear track detectors

This paper reports on radon concentrations in dwellings from fifty different locations of India. The incorporated data were obtained using the passive solid state nuclear track detector technique. The estimated geometric mean value for India is 67.1 Bq m(-3). Chuadanga in Bangladesh had the lowest observed indoor radon concentration of 27.3 Bq m(-3) and Una in the northern part of India had the highest concentration of 281.5 Bq m(-3). This paper discusses the national geometrical mean value in terms of the national geometric mean values of other countries and also in terms of the geological influence. The estimated indoor radon levels are compared with the indoor radon levels as recommended by the International Commission on Radiation Protection (ICRP). It was observed that there are several locations in India where dwellings have higher indoor radon levels than the ICRP recommended value and requires some sort of intervention from regulating authorities. The mean value for indoor radon level given in the report of UNSCEAR 2000 for India needs to be revised.     

Variability in Voc Concentrations in an Urban Area of Delhi

The variability of pollutants is an important factor in determining human exposure to the chemicals. This study presents the result of investigation of variability of Volatile organic compounds (VOCs) in urban area of Delhi, capital of India. Fifteen locations, in five categories namely residential, commercial, industrial, traffic intersections and petrol pump were monitored for one year every month during peak hours in morning and evening. Measurement focused on target VOCs as defined by USEPA. Variability was divided into measurement, spatial, temporal and temporal–spatial interaction components. Temporal component along with temporal–spatial interaction were found to be the major contributors to the variability of measured VOC concentrations. Need of continuous monitoring to capture short–term peak concentration and averages is evident.     

Qualitative Detection of Volatile Organic Compounds in Outdoor and Indoor Air

The present work attempts to identify VOC's in outdoor and indoor air in Mumbai City India. Ambient air was adsorbed on especially fabricated stainless steel cartridge packed with activated coconut charcoal at uniform flow rate. Qualitative identification of VOC's was done by thermally desorbing air from the cartridges and subsequent analysis on Varian GC-MS using NIST Library. The outdoor monitoring locations include residential area, commercial area, industrial, airport, petrol pumps, traffic junctions, arterial roads, highways, slums, parking area, service garages and municipal dump sites. The indoor locations comprised of air-conditioned and non air-conditioned offices, bedrooms, shops and instrumentation laboratory. The identified VOC's include aldehydes, ketones, polynuclear aromatic hydrocarbons, aromatic acids, oxygenated hydrocarbons, amines, esters and halogenated compounds. Thirteen VOCs in outdoor air and seven in indoor air amongst those identified, figure in the list of Hazardous Air Pollutants listed in Title III of the U.S. EPA Clean Air Act Amendments of 1990.     

Contaminants in drinking water and its mitigation using suitable adsorbents: an overview

Various options are applicable for the removal of water pollutants included reverse osmosis, ion exchange, coagulation, co-precipitation, catalytic reduction, herbal filtration, electrodialysis and adsorption. This paper deals with the sorption phenomena for the removal of pollutants from drinking water. Attempts have been made to use low cost sorbents developed by pretreatment/activation/impregnation with alkalis, acids, iron oxide, manganese dioxide, ferric chloride, alum, lime, aluminum salts with natural products/indigenous minerals viz. activated alumina, activated carbon, groundnut husk, saw dust, chemically coated sand, fly ash, zeolites, clay minerals and other plant products. Application of Freundich and Langmuir isotherms were used to assess the adsorption capacity. Equilibrium isotherms were determined at optimum temperature and pH to characterize the sorption process. Statistical parameters such as mass transfer coefficients, multiple regression analysis were applied to establish the mechanism. It is suggested that the characterization of suitable, and exhausted sorbent through the application of fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) is essential to establish its surface bonding. Scope for safety evaluation and risk assessment to human and biosphere may provide the guideline and predication to the regulatory agencies for its sustainable use and safe disposal The ecotoxicological assessment of the leachates and low cost removal technology are discussed in this paper.     

Study of physico-chemical characteristics of water bodies around Jaipur

The present study has been undertaken to evaluate physico-chemical parameters (pH, temperature, dissolved oxygen, free carbon dioxide, alkalinity and hardness) and zinc concentration in water bodies in and around Jaipur. Water samples from Jalmachal Lake, Nevta Lake, Amer Lake and Ramgarh Lake were analysed. Results reveal that the water of Jalmahal Lake is most polluted due to high pH, hardness, alkalinity, free carbon dioxide, zinc content, and a low level of dissolved oxygen. Contrarily Ramgarh Lake is least polluted, as it has high dissolved oxygen and low pH, alkalinity, free carbon dioxide, hardness and zinc content.