Assessing the genotoxic potentials of arsenic in tilapia (Oreochromis mossambicus) using alkaline comet assay and micronucleus test

This experiment was conducted to study the genotoxic potentials of sodium arsenite (NaAsO₂) in freshwater fish Oreochromis mossambicus by using alkaline comet assay and micronucleus (MN) test. Fish were exposed to three different concentrations (3 ppm, 28 ppm and 56 ppm) of arsenic and gill, liver and blood tissue samples were collected after 48 h, 96 h and 192 h of exposure. Arsenic exposure induced DNA damage in all tissues examined in a concentration dependent manner. A significant (p < 0.05) increase in the comet tail DNA (%) of the exposed fish liver, gill, and blood was observed after 48 h and 96 h of exposure, but a decline in DNA damage was recorded in all the tissues at all the three concentrations studied after 192 h of exposure. Liver tissue exhibited significantly (p < 0.05) higher DNA damage at all the concentrations examined, followed by gill and blood. Higher liver tail DNA (51.38 ± 0.21%) refers that it is more prone to injury to arsenic toxicity than the gill and blood. In blood samples arsenic induced micronucleus formation in a concentration dependent manner and highest (5.8 ± 0.46%) value was recorded in 56 ppm after 96 h of exposure, whereas, it was decreased after 192 h of exposure at all the three concentrations of NaAsO₂ examined which refers to the DNA repairing ability of fish to arsenic toxicity. The results of this study depict the genotoxic potentials of arsenic to fish which in turns provide insight on advanced study in aquatic toxicology.     

Toxic responses in primary rat hepatocytes exposed with occupational dust collected from work environment of bone-based industrial unit

In this in vitro study we investigated the toxic responses in hepatocytes treated with occupational dust to which workers are exposed in bone-based industrial units. The present study investigated the toxicity mechanism of bone-based occupational dust, from a particular industrial unit, on isolated rat hepatocytes. The hepatocytes were isolated by collagenase perfusion method and cell viability was determined by trypan blue exclusion and MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay treated with occupational dust at 0.1-1.0 mgmL(-1), for 120 min. The cell viability decreased significantly in a concentration-dependent manner. Dust induced significant membrane damage measured by lactate dehydrogenase (LDH) and glutathione (GSH) release in culture media for 30-, 60- and 120 min treatment duration. The toxicity was found to be correlated with the induction of lipid peroxidation (LPO). In addition, nitric oxide (NO), and hydrogen peroxide (H(2)O(2)) generation by occupational dusts were also found to be time- and concentration-dependent. Over all the present study provides initial evidences for the toxic potential of occupational dust generated in bone-based industries and, therefore, the dust exposure to workers in unorganized industrial units should be controlled.     

Spectroscopic Analysis of Ultraviolet Lamps for Disinfection of Air in Hospitals

In order to have feasibility study of ultraviolet lamps for air disinfection in hospitals, a number of lamps were studied spectroscopically. It was required to understand if these lamps really emitted 253.7 nm. Was the radiation intense enough to disinfect the surrounding air in the hospital? And to know about the percent transmission of the UV rays through the glass of the lamps. The intensity and UV dose were calculated at various distances in air from the lamps. While putting 1-min exposure time in the reciprocity law, the intensity/distance and dose/distance graphs were drawn for various lamps. From the trend line of the graph the distance at which the lamp emitted 10 μW/cm² was calculated. In this study the 1-min exposure time was considered, using the Riley’s designed upper room air disinfection data for 90% kill rate. In the light of the results these lamps were considered fit to be installed either in the air ducts or in the upper room at certain distances for air disinfection, and suggestions were given for the improvement of the system proposed.     

Conservation perceptions and attitudes of semi-nomadic pastoralist towards relocation and biodiversity management: a case study of <Emphasis Type="Italic">Van Gujjars</Emphasis> residing in and around Corbett Tiger Reserve,India

This article examines the perceptions and attitude of the semi-nomadic pastoral community “Van Gujjars” on the use and conservation of natural resources in Corbett Tiger Reserve, India. In this research article, in-depth interview and questionnaire data (n = 340) about demography and perceptions were examined from both qualitative and quantitative information. Respondents have expressed their perception about their own territories, problems, attachments, positive or negative change that occurred during their stay in and around protected area. Respondents overall positive attitudes towards conservation scenarios despite high losses from wildlife while living around protected area suggest that they may support conservation if their livelihood needs are met. Most of the respondents support the concept of conservation, and some respondents have negative attitude towards management authorities, mainly because of restricted access to the forest resources. The study illustrates and suggests a number of options for the viability of resettlement of pastoralist community. A majority of respondents indicated that there is a need for public participation in planning and implementation of resettlement process. Resettlement of Van Gujjar community may be better if exercised with the consensus of all the stakeholders. Resettlement will provide better livelihood opportunity to the pastoral community and enhance the economic status of these people as the educational level increases in time, while also improving habitat recovery leading to better biodiversity conservation. Thus, resettlements could benefit both the pastoral people and the natural resources.     

Mapping field spatial distribution patterns of isoproturon-mineralizing activity over a three-year winter wheat/rape seed/barley rotation

The temporal and spatial variability of the activity of soil microorganisms able to mineralize the herbicide isoproturon (IPU) pesticide was investigated over a three-year long crop rotation between 2008 and 2010. Isoproturon mineralization was higher in 2008, when winter wheat was treated with this herbicide, than in 2009 and 2010, when rape seed and barley were treated with different herbicides. Under laboratory conditions, we showed that isoproturon mineralization was not promoted by sulfonylurea herbicide applied on barley crop in 2010. IPU mineralization was shown to be highly variable at the field scale in years 2009 and 2010. Principal component analyses and analyses of similarities revealed that soil pH and equivalent humidity, and to a lesser extent soil organic matter content and cation exchange capacity (CEC) were the main drivers of isoproturon-mineralizing activity variance. Using a rather simple model that yields the rate of isoproturon mineralization as a function of soil pH and equivalent humidity, we explained up to 85% of the variance observed. Mapping field-scale distribution of isoproturon mineralization over the three-year survey indicated higher variability in 2009 and in 2010 as compared to 2008, suggesting that isoproturon treatment applied to winter wheat promoted isoproturon mineralization activity and reduced its spatial variability. Field-scale distribution of isoproturon mineralization showed important similarity to the distribution of soil pH, equivalent humidity and to a lesser extent to soil organic matter and cation exchange capacity (CEC) thereby confirming our model.     

Enhancing Performance of Sphingobacterium spiritivorum in Bioremediation Phenanthrene Contaminated Sand

Many biodegradation studies have focused on survival of isolated bacteria to increase the bacteria population and subsequently enhance the efficiency of polycyclic aromatic hydrocarbon (PAH) biodegradation. However, there is limited research on enhancing the performance of isolated bacteria through reinoculation. Thus, this study was designed to evaluate the effects of reinoculation on the performance of Sphingobacterium spiritivorum in degradation of phenanthrene contaminated sand. Experiments were performed in three different reactors. Inoculation was performed once (day 0) in reactor 1. In reactor 2, inoculation was performed twice (day 0 and day 5). The bacteria was isolated from reactor 2 and inoculated into reactor 3. The study results show reactor 3 having the highest degradation rate (13.61 mg/kg/day) and percentage removal (95.36 percent). In contrast, without reinoculation in reactor 1, 68.93 percent of phenanthrene was removed. Thus, the performance of S. spiritivorum in phenanthrene degradation can be enhanced through reinoculation. © 2014 Wiley Periodicals, Inc.     

EDTA ameliorates phytoextraction of lead and plant growth by reducing morphological and biochemical injuries in Brassica napus L. under lead stress

Brassica species are very effective in remediation of heavy metal contaminated sites. Lead (Pb) as a toxic pollutant causes number of morphological and biochemical variations in the plants. Synthetic chelator such as ethylenediaminetetraacetic acid (EDTA) improves the capability of plants to uptake heavy metals from polluted soil. In this regard, the role of EDTA in phytoextraction of lead, the seedlings of Brassica napus L. were grown hydroponically. Lead levels (50 and 100 μM) were supplied alone or together with 2.5 mM EDTA in the nutrient culture. After 7 weeks of stress, plants indicated that toxicity of Pb caused negative effects on plants and significantly reduced growth, biomass, chlorophyll content, gas exchange characteristics, and antioxidant enzymes activities such as superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT). Exposure to Pb induced the malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) generation in both shoots and roots. The addition of EDTA alone or in combination with Pb significantly improved the plant growth, biomass, gas exchange characteristics, chlorophyll content, and antioxidant enzymes activities. EDTA also caused substantial improvement in Pb accumulation in Brassica plants. It can be deduced that application of EDTA significantly lessened the adverse effects of lead toxicity. Additionally, B. napus L. exhibited greater degree of tolerance against Pb toxicity and it also accumulated significant concentration of Pb from media.     

Blade thickness effect on the aerodynamic performance of an asymmetric NACA six series blade vertical axis wind turbine in low wind speed

ABSTRACT

Vertical axis wind turbine (VAWT) is an economic and widely used energy converter for converting wind energy into useful form of energy, like mechanical and electrical energy. For efficient energy conversion in low wind speed and to have improved power coefficient of asymmetric blade VAWT, selection of optimum blade thickness is needed thus entailing its detailed investigation with respect to different operating wind speed conditions. Present study methodically explores the impact of thickness to chord (t/c) ratio on aerodynamic performance of a three bladed asymmetrical blade H-Darrieus VAWT at different low wind speed conditions by using 2D unsteady CFD simulations. The optimal t/c is obtained on the basis of maximum power coefficient and average moment coefficient of the turbine. The aerodynamic performance curves are obtained at different operating and t/c conditions and the performance insights are corroborated with the findings from the flow physics study to come to some concrete conclusions on the effects of the thickness to chord ratio. The present study identifies large blade curvature to create a large diverging passage on the blade suction surface as the prominent reason for aerodynamic performance drop at a high t/c ratio.     

Vehicular stress a cause for heavy metal accumulation and change in physico-chemical characteristics of road side soils in Pahalgam

In an effort to determine vehicular impact on soil quality, soil samples were collected from three different zones (Pahalgam, Batakote, and Chandanwari) in Pahalgam forest ecosystem. Results showed that a significant decrease in moisture content, organic carbon, available nitrogen, and potassium was observed in nearby road side soils. However, pH was observed to be on neutral side and available phosphorus recorded high concentration. The concentration of heavy metals Pb²⁺, Cu²⁺, Zn²⁺, Ni²⁺, and Cd²⁺ estimated was also significantly high. Furthermore, concentration of Pb²⁺ at high vehicular load subzones was observed to be highest (1.168 mg/Kg) followed by Zn²⁺ (0.896 mg/Kg), Ni²⁺ (0.649 mg/Kg), Cu²⁺ (0.415 mg/Kg), and Cd²⁺ (0.079 mg/Kg). An inter-zone analysis revealed that the concentration of the heavy metals (Pb²⁺?>?Ni²⁺?>?Cd²⁺) was observed to follow the trend, Z-I?>?Z-II?>?Z-III. Variation along the temporal gradient and the impact on soil qualities were notably higher in summer. Vehicular pollution to a great extent impacts physico-chemical characteristics and more interestingly adds substantial concentration of heavy metals in soils.