Variations in some environmental characteristics including C and N stable isotopic composition of suspended organic matter in the Mandovi estuary

Chemical and isotopic (??¹³C and ??¹⁵N) investigation of the Mandovi estuary along the Indian west coast affected strongly by the seasonal monsoon cycle was carried out. The Mandovi estuary is a major waterway for Goa and extensively used for transportation of iron and manganese ore. In addition, with large population centers as well as agricultural fields located on its shores, the estuary is assumed to have been influenced by human activities. Measurements of chemical and isotopic parameters made in the lower part of the estuary during the southwest (SW) monsoon and post-monsoon seasons reveal distinct changes, and it is observed that despite considerable enrichment of macronutrients during the SW monsoon, productivity of the estuary (phytoplankton biomass), as inferred from the chlorophyll-a content, is not as high as expected. This is due to occurrences of high turbidity and cloud cover that limits photosynthetic productivity. The isotopic characterization (C and N isotopes) of suspended organic matter produced/transported during the monsoon and post-monsoon seasons of year 2007 provides a baseline dataset for future isotopic studies in such type of tropical estuaries.     

Protection of palak (Beta vulgaris L. var Allgreen) plants from ozone injury by ethylenediurea (EDU): Roles of biochemical and physiological variations in alleviating the adverse impacts

Ameliorative effects of ethylenediurea (N-[2-(2-oxo-1-imidazolinidyl) ethyl]-N′ phenylurea, abbreviated as EDU) against ozone stress were studied on selected growth, biochemical, physiological and yield characteristics of palak (Beta vulgaris L. var Allgreen) plants grown in field at a suburban site of Varanasi, India. Mean eight hourly ozone concentration varied from 52 to 73 ppb which was found to produce adverse impacts on plant functioning and growth characteristics. The palak plants were treated with 300 ppm EDU at 10 days after germination at 10 days interval up to the plant maturity. Lipid peroxidation in EDU treated plants declined significantly as compared to non-EDU treated ones. Significant increment in F_v/F_m ratio in EDU treated plants as compared to non-EDU treated ones was recorded. EDU treated plants showed significant increment in ascorbic acid contents and reduction in peroxidase activity as compared to non-EDU treated ones. As a result of the protection provided by EDU against ozone induced stress on biochemical and physiological characteristics of palak, the morphological parameters also responded positively. Significant increments were recorded in shoot length, number of leaves plant⁻¹, leaf area and root and shoot biomass of EDU treated plants as compared to non-EDU treated ones. Contents of Na, K, Ca, Mg and Fe were higher in EDU treated plants as compared to non-EDU treated ones. The present investigation proves the usefulness of EDU in partially ameliorating ozone injury in ambient conditions.     

Assessing the impact of ambient ozone on growth and productivity of two cultivars of wheat in India using three rates of application of ethylenediurea (EDU)

Three rates of ethylenediurea were used to assess the impact of ambient ozone on growth and productivity of wheat (Triticum aestivum L) cultivars "Malviya 533" (M 533) and "Malviya 234" (M 234) at a suburban site near Varanasi, India, beginning in December. Wheat plants were treated with EDU at 0, 150, 300 and 450 ppm as soil drenches at 10-day intervals. EDU treatment affected plant growth, with effects varying with cultivar, age, and EDU concentration. Seed yield was improved for M 533 at 150 ppm EDU, while yield improved for M 234 at 300 and 450 ppm EDU. M 533 appears to be more resistant to ozone than M 234. Overall results confirmed that EDU is very useful in assessing the effect of ambient ozone in India.     

Ethylenediurea as a potential tool in evaluating ozone phytotoxicity: a review study on physiological,biochemical and morphological responses of plants

Present-day climate change scenario has intensified the problem of continuously increasing ground-level ozone (O₃), which is responsible for causing deleterious effects on growth and development of plants. Studies involving use of ethylenediurea (EDU), a chemical with antiozonant properties, have given some promising results in evaluating O₃ injury in plants. The use of EDU is especially advantageous in developing countries which face a more severe problem of ground-level O₃, and technical O₃-induced yield loss assessment techniques like open-top chambers cannot be used. Recent studies have detected a hormetic response of EDU on plants; i.e. treatment with higher EDU concentrations may or may not show any adverse effect on plants depending upon the experimental conditions. Although the mode of action of EDU is still debated, it is confirmed that EDU remains confined in the apoplastic regions. Certain studies indicate that EDU significantly affects the electron transport chain and has positive impact on the antioxidant defence machinery of the plants. However, the mechanism of protecting the yield of plants without significantly affecting photosynthesis is still questionable. This review discusses in details the probable mode of action of EDU on the basis of available data along with the impact of EDU on physiological, biochemical, growth and yield response of plants under O₃ stress. Data regarding the effect of EDU on plant ‘omics’ is highly insufficient and can form an important aspect of future EDU research.     

Usefulness of automated chromatography for rapid fetal blood analysis for second trimester prenatal diagnosis of β-thalassemia

Prenatal diagnosis of β-thalassemia is now ideally done in the first trimester of pregnancy by chorionic villus tissue DNA analysis. Nevertheless, fetal blood analysis in the second trimester is required either when the mutation in both parents cannot be characterised or when the couple comes late for investigations. We evaluated the usefulness of analysis of fetal blood on the Biorad Variant Hemoglobin Testing System using the β-thalassemia short programme in comparison with the conventional globin biosynthesis in 58 pregnancies. The β/α biosynthesis ratios in 13 homozygous fetuses ranged from 0 to 0.03 and the adult hemoglobin (HbA) levels by automated chromatography varied from 0% to 0.4%. The normal or heterozygous fetuses had β/α ratios of >0.04 and HbA levels ranging from 2.1% to 10.6%. In 17 fetuses we also correlated the β gene mutations with the predicted genotypes using automated high-performance liquid chromatography (HPLC). Follow-up of 18 unaffected fetuses using the Variant System at birth showed a significant increase in HbA levels. Copyright © 2002 John Wiley & Sons, Ltd.     

Net-cost model for workplace interventions

PROBLEM: Few methods exist for comprehensively examining the costs and benefits of ergonomic interventions applicable to a variety of economic sectors and settings. METHODS: An instrument for data collection and data analysis at the facility level is presented. In this net-cost model intervention costs are defined by equipment and labor costs for the interventions as well as the avoided costs of lost work time, medical care, and productivity improvements. RESULTS: Net-cost estimates for three case studies show that ergonomic interventions applied appropriately can result in substantial cost savings for the companies. DISCUSSION: It would be prudent to incorporate a protocol for collecting cost and effectiveness data in the standard operating procedures of companies introducing ergonomic interventions. Validation of the net-cost model through prospective studies is necessary. IMPACT ON INDUSTRY: This model may be used to determine the net-cost of implemented or proposed ergonomic interventions in industrial facilities.     

Application of HYDRUS 1D model for assessment of phenol–soil adsorption dynamics

Laboratory-scale batch, vertical, and horizontal column experiments were conducted to investigate the attenuative capacity of a fine-grained clayey soil of local origin in the surrounding of a steel plant wastewater discharge site in West Bengal, India, for removal of phenol. Linear, Langmuir, and Freundlich isotherm plots from batch experimental data revealed that Freundlich isotherm model was reasonably fitted (R ²?=?0.94). The breakthrough column experiments were also carried out with different soil bed heights (5, 10, and 15 cm) under uniform flow to study the hydraulic movements of phenol by evaluating time concentration flow behavior using bromide as a tracer. The horizontal migration test was also conducted in the laboratory using adsorptive phenol and nonreactive bromide tracer to explore the movement of solute in a horizontal distance. The hydrodynamic dispersion coefficients (D) in the vertical and horizontal directions in the soil were estimated using nonlinear least-square parameter optimization method in CXTFIT model. In addition, the equilibrium convection dispersion model in HYDRUS 1D was also examined to simulate the fate and transport of phenol in vertical and horizontal directions using Freundlich isotherm constants and estimated hydrodynamic parameters as input in the model. The model efficacy and validation were examined through statistical parameters such as the coefficient of determination (R ²), root mean square error and design of index (d).     

Up to 399 mV bioelectricity generated by a rice paddy-planted microbial fuel cell assisted with a blue-green algal cathode

Environmental Chemistry Letters - Microbial fuel cells are used as an alternative source of energy and for microbial degradation of waste and pollutants. Different types of microbial fuel cells...