Estimates of upwelling rates in the Arabian Sea and the equatorial Indian Ocean based on bomb radiocarbon

Radiocarbon measurements were made in the water column of the Arabian Sea and the equatorial Indian Ocean during 1994, 1995 and 1997 to assess the temporal variations in bomb 14C distribution and its inventory in the region with respect to GEOSECS measurements made during 1977-1978. Four GEOSECS stations were reoccupied (three in the Arabian Sea and one in the equatorial Indian Ocean) during this study, with all of them showing increased penetration of bomb 14C along with decrease in its surface water activity. The upwelling rates derived by model simulation of bomb 14C depth profile using the calculated exchange rates ranged from 3 to 9 m a(-1). The western region of the Arabian Sea experiencing high wind-induced upwelling has higher estimated upwelling rates. However, lower upwelling rates obtained for the stations occupied during this study could be due to reduced 14C gradient compared to that during GEOSECS.     

Biodiversity of mosquitoes in Manipur State and their medical significance

Entomological studies conducted during monsoon and post-monsoon season in Manipur State revealed the presence of fifty-five species of mosquitoes under ten genera. Out of the seventeen Anopheles species recorded, Anopheles aconitus, An. dirus and An. nivipes were recorded for the first time from the state. The present study has confirmed the existence of An. dirus, the major malaria vector in the Northeast from a selected area of the state. Among Culicines, four species viz., Aedes nigrostriatus, Malaya genurostris, Aediomyia catasticta and Toxorhynchites splendens which were not reported earlier from this state have been recorded in the present study. With the addition of these seven species of mosquitoes to the earlier record of mosquitoes so far reported from Manipur, the mosquito fauna swells up to one hundred and eleven including the major vectors of malaria of the Northeast and the potential vectors of Japanese encephalitis and dengue virus transmission in India.     

Methods to convert lignocellulosic waste into biohydrogen,biogas, bioethanol,biodiesel and value-added chemicals: a review

Environmental Chemistry Letters - In the context of climate change and the circular economy, there is an urgent need to develop biofuels and value-added chemicals from lignocellulosic waste such as...     

Amperometric Detection of Pesticides Using Polymer Electrodes

Abstact The real time monitoring of some organophosphorus based pesticides is of great concern to environmentalists because the widespread use of pesticides is causing severe health hazards to all living beings and also hampering our ecological balance. The traditional methods of measurement of pesticide residues are time consuming, need sample pre-treatment, and lack desired specificity and accuracy. We have developed an amperometric biosensor for indirect measurement of the pesticide concentration precisely in ppb level. The method is based on the action of two enzymes namely acetylcholine esterase and choline oxidase which are uniquely immobilized in a polymeric porous network directly on the working electrode of a screen-printed sensor. Polyacrylamide matrix has been prepared by copolymerisation of acrylamide andN,N′-methylenebisacrylamide using Potassium peroxodisulphate (K₂S₂O₈) as initiator. A linear relationship was obtained between the range of 0 to 10 ppb.     

Global gene expression and Ingenuity biological functions analysis on PCBs 153 and 138 induced human PBMC in vitro reveals differential mode(s) of action in developing toxicities

Several reports have indicated that low level of polychlorinated biphenyl (PCB) exposure can adversely affect a multitude of physiological disorders and diseases in in vitro, in vivo, and as reported in epidemiological studies. This investigation is focused on the possible contribution of two most prevalent PCB congeners in vitro in developing toxicities. We used PCBs 138 and 153 at the human equivalence level as model agents to test their specificity in developing toxicities. We chose a global approach using oligonucleotide microarray technology to investigate modulated gene expression for biological effects, upon exposure of PCBs, followed by Ingenuity Pathway Analysis (IPA), to understand the underlying consequence in developing disease and disorders. We performed in vitro studies with human peripheral blood mononuclear cells (PBMC), where PBMC cells were exposed to respective PCBs for 48 h. Overall, our observation on gene expression indicated that PCB produces a unique signature affecting different pathways, specific for each congener. While analyzing these data through IPA, the prominent and interesting disease and disorders were neurological disease, cancer, cardiovascular disease, respiratory disease, as well as endocrine system disorders, genetic disorders, and reproductive system disease. They showed strong resemblances with in vitro, in vivo, and in the epidemiological studies. A distinct difference was observed in renal and urological diseases, organisimal injury and abnormalities, dental disease, ophthalmic disease, and psychological disorders, which are only revealed by PCB 138 exposure, but not in PCB 153. The present study emphasizes the challenges of global gene expression in vitro and was correlated with the results of exposed human population. The microarray results give a molecular mechanistic insight and functional effects, following PCB exposure. The extent of changes in genes related to several possible mode(s) of action highlights the changes in cellular functions and signaling pathways that play major roles. In addition to understanding the pathways related to mode of action for chemicals, these data could lead to the identification of genomic signatures that could be used for screening of chemicals for their potential to cause disease and developmental disorders.     

Removal of mercury(II) from aqueous solutions using the leaves of the Rambai tree (Baccaurea motleyana)

This study was undertaken to evaluate the biosorption potential of a natural, low-cost biosorbent, Rambai leaves (Baccaurea motleyana), to remove trace amounts of Hg(II) from aqueous solutions. It was found that the amount of Hg(II) biosorption by Rambai leaves increased with initial metal ion concentration, contact time, and solution pH but decreased as the amount of biosorbent increased. The maximum biosorption capacity was 121.95 mg/g for an initial concentration range of 5 to 120 ppb. Overall, kinetic studies showed that the Hg(II) biosorption process followed pseudo-second-order kinetics based on pseudo-first-order and intraparticle diffusion models. Isotherm data revealed that the biosorption process followed both Freundlich and Langmuir isotherms. The value of separation factor, R(L), from the Langmuir equation and rate of biosorption, n, from the Freundlich model also indicated favorable adsorption.     

Review of biosolids management options and co-incineration of a biosolid-derived fuel

This paper reviews current biosolids management options, and identifies incineration as a promising technology. Incineration is attractive both for volume reduction and energy recovery. Reported emissions from the incineration of biosolids were compared to various regulations to identify the challenges and future direction of biosolids incineration research. Most of the gaseous and metal emissions were lower than existing regulations, or could be met by existing technologies. This paper also presents the results of an experimental study to investigate the potential use of biosolids for co-incineration with wood pellets in a conventional wood pellet stove. Pilot scale combustion tests revealed that co-incineration of 10% biosolids with 90% premium grade wood pellets resulted in successful combustion without any significant degradation of efficiency and emissions.     

Biodegradation of Epoxy and MF Modified Polyurethane Films Derived from a Sustainable Resource

Mesua ferrea L. seed oil (MFLSO) modified polyurethanes blends with epoxy and melamine formaldehyde (MF) resins have been studied for biodegradation with two techniques, namely microbial degradation (broth culture technique) and natural soil burial degradation. In the former technique, rate of increase in bacterial growth in polymer matrix was monitored for 12 days via a visible spectrophotometer at the wavelength of 600 nm using McFarland turbidity as the standard. The soil burial method was performed using three different soils under ambient conditions over a period of 6 months to correlate with natural degradation. Microorganism attack after the soil burial biodegradation of 180 days was realized by the measurement of loss of weight and mechanical properties. Biodegradation of the films was also evidenced by SEM, TGA and FTIR spectroscopic studies. The loss in intensity of the bands at ca. 1735 cm⁻¹ and ca. 1050 cm⁻¹ for ester linkages indicates biodegradation of the blends through degradation of ester group. Both microbial and soil burial studies showed polyurethane/epoxy blends to be more biodegradable than polyurethane/MF blends. Further almost one step degradation in TG analysis suggests degradation for both the blends to occur by breakage of ester links. The biodegradation of the blends were further confirmed by SEM analyses. The study reveals that the modified MFLSO based polyurethane blends deserve the potential to be applicable as “green binders” for polymer composite and surface coating applications.