Synthesis of highly fluorescent and water soluble graphene quantum dots for detection of heavy metal ions in aqueous media

Environmental Science and Pollution Research - Fluorescent graphene quantum dots (GQDs) are nanomaterials which possess unique properties that show great potential in different applications. In...     

Factors affecting the performance of a solar still and productivity enhancement methods: A review

Environmental Science and Pollution Research - Good-quality drinking water is an essential requirement for a healthy and sustainable future. In the current scenario, people living in remote areas...     

Hydrogenation properties and kinetic study of MgH2 - x wt% AC nanocomposites prepared by ball milling

Environmental Science and Pollution Research - The high de-/hydrogenation temperature of magnesium hydride is still a challenge in solid-state hydrogen storage system for automobiles applications....     

Dissolution of steel slags in aqueous media

Environmental Science and Pollution Research - Steel slag is a major industrial waste in steel industries, and its dissolution behavior in water needs to be characterized in the larger context of...     

Study on assessment of slope stability and mixed disposal of overburden in voids of Singrauli Coalfield

The mining industry can be considered the backbone of the Indian economy as well as facilitating the power that drives most of the other industries in the company. The overburden and waste rocks produced during coal mining are major concerns in regard to the amount of land that is required for their disposal, as well as the stability of dumps for these materials, which are of increasing height. Land reclamation issues are also a concern. In this work the adverse impacts caused by the dumping of overburden on land and acidic mine water on water bodies is discussed. Remote sensing tools were used along with the laboratory experimentation to assess the various impacts. This study also shows that silt released from waste dumps, can affected the angle of repose of the overburden dump slope. The angle of repose of the overburden materials varies with particle size composition. Thus, use of in‐pit crushers in large opencast mining operations can effectively reduce the area locked under the waste dumps. The acid neutralization potential of fly ash and overburden for the treatment of acid water was tested in the laboratory by using fly ash and waste rock materials on acidic coalfield water. The results are encouraging, and fly ash may prove to be a good acid neutralizer when used in conjunction of coal overburden material.     

Association of Streptomyces community composition determined by PCR-denaturing gradient gel electrophoresis with indoor mold status

Both Streptomyces species and mold species have previously been isolated from moisture-damaged building materials; however, an association between these two groups of microorganisms in indoor environments is not clear. In this study, we used a culture-independent method, PCR-denaturing gradient gel electrophoresis (PCR-DGGE), to investigate the composition of the Streptomyces community in house dust. Twenty-three dust samples each from two sets of homes categorized as high-mold and low-mold based on mold-specific quantitative PCR analysis were used in the study. Taxonomic identification of prominent bands was performed by cloning and sequencing. Associations between DGGE amplicon band intensities and home mold status were assessed using univariate analyses as well as multivariate recursive partitioning (decision trees) to test the predictive value of combinations of bands intensities. In the final classification tree, a combination of two bands was significantly associated with mold status of the home (p?=?0.001). The sequence corresponding to one of the bands in the final decision tree matched a group of Streptomyces species that included Streptomyces coelicolor and Streptomyces sampsonii, both of which have been isolated from moisture-damaged buildings previously. The closest match for the majority of sequences corresponding to a second band consisted of a group of Streptomyces species that included Streptomyces hygroscopicus, an important producer of antibiotics and immunosuppressors. Taken together, the study showed that DGGE can be a useful tool for identifying bacterial species that may be more prevalent in mold-damaged buildings.     

Forecasting Daily Maximum Surface Ozone Concentrations in Brunei Darussalam—An ARIMA Modeling Approach

Abstract

A time series approach using autoregressive integrated moving average (ARIMA) modeling has been used in this study to obtain maximum daily surface ozone (O₃) concentration forecasts. The order of the fitted ARIMA model is found to be (1,0,1) for the surface O₃ data collected at the airport in Brunei Darussalam during the period July 1998-March 1999. The model forecasts of one-day-ahead maximum O₃ concentrations have been found to be reasonably close to the observed concentrations. The model performance has been evaluated on the basis of certain commonly used statistical measures. The overall model performance is found to be quite satisfactory as indicated by the values of Fractional Bias, Normalized Mean Square Error, and Mean Absolute Percentage Error as 0.025, 0.02, and 13.14% respectively.     

Mitigation potential of important farm and forest trees: a potentiality for clean development mechanism afforestation reforestation (CDM A R) project and reducing emissions from deforestation and degradation,along with conservation and enhancement of carbon stocks (REDD+)

The effectiveness and integrity of forest-based emissions reduction schemes such as Clean Development Mechanism Afforestation Reforestation (CDM A R) project and Reducing Emissions from Deforestation and Degradation (REDD+), along with conservation and enhancement of carbon (C) stocks implementation and assessment in developing countries are required not only, the appropriate monitoring and evaluation, rather the precise values of constants being used to estimate the C stocks or C credit in place of default or guess value. Estimates are reported of the C content of wood of four forest species (Shorea robusta, Pinus roxburghii, Tectona grandis and Cinnamomum camphora) and two important farm species (Populus deltoides and Eucalyptus treticornis) in the temperate region of Indian Himalayas, derived using the ash content method. These species were considered keeping in view of their potentiality for the C sequestration and storage projects across the developing countries specifically the South East Asian Countries. The specific gravity, ash content and C proportion is estimated for these six species by selecting random woods pieces. These estimates are designed to improve the calculations of biomass C for use in estimation of C credits in the developing region under CDM A R projects and REDD+ program supported by developed country. Regression analysis of C prediction models revealed that, for all six species, C content may be estimated through specific gravity of the wood by a linear equation without intercept. Indirectly, this results also implies that among the two farm trees, eucalyptus has high potentiality for C capturing and among four forest trees, Shorea robusta has high potentiality, therefore these two should have preference for plantation/regeneration as well as for conservation.     

Metal toxicity assessment of mobile phone parts using Milli Q water

Environmentally safe disposal of end-of-life (EoL) or discarded mobile phone is a serious problem on account of their ever increasing number and toxic metals contents. In the present work, metal toxicity of mobile phone plastics, printed wire boards (PWBs) and batteries were assessed through dynamic batch leaching using Milli Q (MQ) water. Phone plastics failed Toxicity Characterization Leaching Procedure (TCLP) and Waste Extraction Test (WET) for Pb as the cumulative amount of Pb leached from plastics (5.33 mg/l) exceeded the regulatory limits (5.0 mg/l) used in characterizing a waste as hazardous. Similarly, the average cumulative amount (21.83 mg/l) of Ni leached from PWBs exceeded the regulatory limit of 20 mg/l and thus PWBs failed WET. Metals leached from batteries in small amounts (Cr: 0.40 mg/l and Ni: 0.15 mg/l). The presence of Fe in the batteries and its precipitation as oxides/hydroxides in the leaching solution hindered the leaching of other metals in MQ water. Both plastics and PWBs should be treated as hazardous waste and should not be disposed in open landfills. Further, MQ water leaching could provide good simulation of metals leaching from the mobile phones disposed at landfill sites.     

Contribution of point sources and non-point sources to nutrient and carbon loads and their influence on the trophic status of the Ganga River at Varanasi,India

To determine the possible contributions of point and non-point sources to carbon and nutrient loading in the Ganga River, we analyzed N, P, and organic carbon (OC) in the atmospheric deposits, surface runoff, and in the river along a 37-km stretch from 2013 to 2015. We also assessed the trophic status of the river as influenced by such sources of nutrient input. Although the river N, P, and productivity showed a declining trend with increasing discharge, runoff DOC and dissolved reactive phosphorus (DRP) increased by 88.05 and 122.7% between the Adpr and Rjht sites, indicating contributions from atmospheric deposition (AD) coupled with land use where agriculture appeared to be the major contributor. Point source input led to increased river concentrations of NO₃ ^?, NH₄ ⁺, DRP, and DOC by 10.5, 115.9, 115.2, and 67.3%, respectively. Increases in N, P, and productivity along the gradient were significantly negatively correlated with river discharge (p < 0.001), while river DOC and dissolved silica showed positive relationships. The results revealed large differences in point and non-point sources of carbon and nutrient input into the Ganga River, although these variations were strongly influenced by the seasonality in surface runoff and river discharge. Despite these variations, N and P concentrations were sufficient to enhance phytoplankton growth along the study stretch. Allochthonous input together with enhanced autotrophy would accelerate heterotrophic growth, degrading the river more rapidly in the near future. This study suggests the need for large-scale inter-regional time series data on the point and non-point source partitioning and associated food web dynamics of this major river system.