Biomonitoring of heavy metals by pollen in urban environment

Abstract Industrial development and consumption of petroleum products leads to increase air pollution levels especially in urban and industrial areas. Heavy metal components associated with air pollutants have far reaching effects with respect to economic and ecological importance of pollens. The pollens are male reproductive organs of the plant and travel through air from flower to flower for pollination purpose. During this period they are exposed to air pollutants. Present investigation thus pertains to study of effect of air pollutants on pollens especially biosorption and bioaccumulation of heavy metals. The pollens of three commonly occurring plants namely Cassia siamea, Cyperus rotundus, Kigelia pinnata have been studied from the NH-6 of Nagpur city, India. The pollens exposed to polluted air showed the presence of higher concentrations of Ca, Al and Fe as compared to unexposed pollens. Higher concentration of these metals was observed in Cyperus rotundus followed by Cassia siamea and Kigelia pinnata. These results indicate that pollens act as good indicator of air pollution giving results in short time of exposure of 5–10 h. Apart from this, it is also reported that some of these metals play crucial role in the metabolic activity in pollens for example Calcium is necessary for growth of pollen tube and other metabolic activities in pollens. The presence of these metals in pollens may also enhance the allergenicity of the pollens. Similarly accumulation of heavy metals may also deteriorate the quality of pollen for their economical use. The viability of pollen is also affected by these pollutants in sensitive species leading to impairment of their fertility.     

Bioleaching of copper from large printed circuit boards for synthesis of organic-inorganic hybrid

Environmental Science and Pollution Research - The present study described a process for copper (Cu) bioleaching from waste printed circuit boards (PCBs). The 45 (±?0.18) mg/g Cu was...     

Characterization of major pollution events (dust, haze, and two festival events) at Agra, India

Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO₂, SO₂, and O₃) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca²⁺, Cl^?, NO₃ ^?, and SO₄ ^2? were the most abundant ions and Ca²⁺ alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO₃ ^?, SO₄ ^2?, and NH₄ ⁺, were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO₄ ^2? concentration (17.8 μg?m^?3) was highest followed by NO₃ ^?, K⁺, and Cl^? while the Holi samples were strongly enriched with Cl^? and K⁺ which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched with particles of crustal origin.     

A GFP-based bacterial biosensor with chromosomally integrated sensing cassette for quantitative detection of Hg(II) in environment

A mercury biosensor was constructed by integrating biosensor genetic elements into E. coli JM109 chromosome in a single copy number, using the attP/attB recombination mechanism of λphage. The genetic elements used include a regulatory protein gene (merR) along with operator/promoter (O/P) derived from the mercury resistance operon from pDU1358 plasmid of Serratia marcescens. The expression of reporter gene gfp is also controlled by merR/O/P. Integration of the construct into the chromosome was done to increase the stability and precision of the biosensor. This biosensor could detect Hg(II) ions in the concentration range of 100-1700 nmol/L, and manifest the result as the expression of GFP. The GFP expression was significantly different (P ≤ 0.05) for each concentration of inducing Hg(II) ions in the detection range, which reduces the chances of misinterpretation of results. A model using regression method was also derived for the quantification of the concentration of Hg(II) in water samples.     

Removal of arsenic from water by electrocoagulation

In the present study electrocoagulation (EC) has been evaluated as a treatment technology for arsenite [As(III)] and arsenate [As(V)] removal from water. Laboratory scale experiments were conducted with three electrode materials namely, iron, aluminum and titanium to assess their efficiency. Arsenic removal obtained was highest with iron electrodes. EC was able to bring down aqueous phase arsenic concentration to less than 10 microgl(-1) with iron electrodes. Current density was varied from 0.65 to 1.53 mAcm(-2) and it was observed that higher current density achieved rapid arsenic removal. Experimental results at different current densities indicated that arsenic removal was normalized with respect to total charge passed and therefore charge density has been used to compare the results. Effect of pH on arsenic removal was not significant in the pH range 6-8. Comparative evaluation of As(III) and As(V) removal by chemical coagulation (with ferric chloride) and electrocoagulation has been done. The comparison revealed that EC has better removal efficiency for As(III), whereas As(V) removal by both processes was nearly same. The removal mechanism of As(III) by EC seems to be oxidation of As(III) to As(V) and subsequent removal by adsorption/complexation with metal hydroxides generated in the process.     

Bracketing team boundary spanning: An examination of task‐based,team‐level,and contextual antecedents

There is growing recognition that teams do not function in a vacuum and that external boundary activities are important predictors of team performance, effectiveness, and knowledge sharing. In the past, researchers have focused on the effects of team composition or task characteristics as antecedents of critical boundary spanning activities. However, less effort has been directed at understanding how antecedents at multiple levels can simultaneously influence boundary spanning behavior in teams. This paper takes stock of over 20 years of research on the topic of team boundary spanning. Adopting a “bracketing” approach etc., we develop a multi‐level theoretical model to guide future research on the determinants of team boundary spanning. This model specifies task‐based, team‐level, and contextual antecedents of team boundary spanning and outlines the contingencies shaping the emergence of effective boundary‐management behavior in teams. Copyright © 2008 John Wiley & Sons, Ltd.     

Treatment of wastewater by electrocoagulation: a review

The electrocoagulation (EC) process is an electrochemical means of introducing coagulants and removing suspended solids, colloidal material, and metals, as well as other dissolved solids from water and wastewaters. The EC process has been successfully employed in removing pollutants, pesticides, and radionuclides. This process also removes harmful microorganisms. More often during EC operation, direct current is applied and electrode plates are sacrificed (dissolved into solution). The dissolution causes an increased metal concentration in the solution that finally precipitates as oxide precipitates. Due to improved process design and material of construction, the EC process is being widely accepted over other physicochemical processes. Presently, this process has gained attention due to its ability to treat large volume and for its low cost. The aim of this study is to review the mechanism, affecting factors, process, and application of the electrocoagulation process.     

Diversity of birds at Panipat refinery, Haryana (India)

Avifaunal study was carried out in Panipat refinery area before and after commissioning. A total of 63 birds were observed during the study, of which 39 and 49 birds were present during 1992 and 2001 respectively. Of these, 25 birds were common during both the study period. Blue rock pigeon was most dominant during 1992 whereas house sparrow was dominant during 2001. Species diversity index was found to be 5.26 and 6.64 in respective years. Jaccard's and Sorenson similarity indices were 0.40 and 0.57 respectively. Majority of birds were insectivorous in habits followed by granivorous birds in 1992 and piscivorous birds in 2001. The study reveals that less diversity was observed in 1992 when Panipat refinery was commissioned, but more birds especially aquatic ones were observed after the commissioning of the refinery. This has been attributed to increase in birds habitats due to developments of wetlands in and outside refinery, development of green belt around refinery and increase in green cover of area due to boosting of agroforestry and social forestry.     

Inhibition kinetics of certain enzymes in the nervous tissue of vector snail Lymnaea acuminata by active molluscicidal components of Sapindus mukorossi and Terminalia chebula

Effect of active molluscicidal components of Sapindus mukorossi and Terminalia chebula on the acetylcholinesterase (AChE), acid and alkaline phosphatase (ACP/ALP) activity in the nervous tissue of freshwater snail Lymnaea acuminata were studied. In vivo and in vitro exposure of saponin (active component of S. mukorossi pericarp) and tannic acid (active component of T. chebula) significantly inhibited the AChE, ACP and ALP activity in the nervous tissue of L. acuminata. The inhibition kinetics of these enzymes indicate that saponin and tannic acid caused competitive and competitive-non-competitive inhibition of AChE, respectively. Saponin also caused competitive and competitive-non-competitive inhibition of ACP and ALP, respectively, whereas tannic acid caused competitive-non-competitive inhibition of ACP and ALP. Thus the inhibition of AChE, ACP and ALP by saponin and tannic acid in the nervous tissue of L. acuminata may be the cause of molluscicidal activity of S. mukorossi and T. chebula.     

Data integration across borders: a case study of the Abbotsford‐Sumas aquifer (British Columbia/Washington State)1

Abstract: Integrating spatial datasets from diverse sources is essential for cross‐border environmental investigations and decision‐making. This is a little investigated topic that has profound implications for the availability and reliability of spatial data. At present, ground‐water hydrostratigraphic models exist for both the Canadian or for the United States (U.S.) portion of the aquifer but few are integrated across the border. In this paper, we describe the challenges of integrating multiple source, large datasets for development of a ground‐water hydrostratigraphic model for the Abbotsford‐Sumas Aquifer. Growing concerns in Canada regarding excessive withdrawal south of the border and in the U.S. regarding nitrate contamination originating north of the border make this particular aquifer one of international interest. While much emphasis in GIScience is on theoretical solutions to data integration, such as current ontology research, this study addresses pragmatic ways of integrating data across borders. Numerous interoperability challenges including the availability of data, metadata, data formats and quality, database structure, semantics, policies, and cooperation are identified as inhibitors of data integration for cross‐border studies. The final section of the paper outlines two possible solutions for standardizing classification schemes for ground‐water models – once data heterogeneity has been addressed.