Assessment of oxidative stress markers and concentrations of selected elements in the leaves of Cassia occidentalis growing wild on a coal fly ash basin

Assessment of oxidative stress levels and tissue concentrations of elements in plants growing wild on fly ash basins is critical for realistic hazard identification of fly ash disposal areas. Hitherto, levels of oxidative stress markers in plants growing wild on fly ash basins have not been adequately investigated. We report here concentrations of selected metal and metalloid elements and levels of oxidative stress markers in leaves of Cassia occidentalis growing wild on a fly ash basin (Badarpur Thermal Power Station site) and a reference site (Garhi Mandu Van site). Plants growing on the fly ash basin had significantly high foliar concentration of As, Ni, Pb and Se and low foliar concentration of Mn and Fe compared to the plants growing on the reference site. The plants inhabiting the fly ash basin showed signs of oxidative stress and had elevated levels of lipid peroxidation, electrolyte leakage from cells and low levels of chlorophyll a and total carotenoids compared to plants growing at the reference site. The levels of both protein thiols and nonprotein thiols were elevated in plants growing on the fly ash basin compared to plants growing on the reference site. However, no differences were observed in the levels of cysteine, reduced glutathione and oxidized glutathione in plants growing at both the sites. Our study suggests that: (1) fly ash triggers oxidative stress responses in plants growing wild on fly ash basin, and (2) elevated levels of protein thiols and nonprotein thiols may have a role in protecting the plants from environmental stress.     

Environmental impact assessment of a proposed info-tech complex in East Calcutta wetlands

An info-tech complex is proposed for 286 acres (116 ha) of land within the East Calcutta wetlands. The proposed site is 15 km east of Kolkata city and only 8 km south of Dum Dum airport. The site is vacant, with pockets of agricultural land and a few degrading water-logged areas. In order to assess the likely impact of the proposed development on the environment, a rapid environmental impact assessment of an area of 10 km radius from the centre of the project site was carried out. The present status of the environment with respect to ambient air, surface water, groundwater, soil, landuse, noise, and socio-economics of the core and buffer zone has been documented and correlated with 24 project activities during construction, development and operational phases. The frequency of adverse impacts is greater than that of beneficial impacts. Out of the total adverse impacts 20 are short term, reversible and have a low magnitude. The total impact score for the proposed project is (–)468.75 and as per the Assessment Value Index Scale the environmental impact of the proposed project activities is no appreciable impact. But there are certain sectors where the environment will be adversely impacted. Therefore, appropriate measures have been suggested to ameliorate the adverse impacts. It is envisaged that if these measures are implemented then there will be an improvement in the quality of the environment, as well as life, by 687.5 units.     

Lower Leg Injury Reference Values and Risk Curves from Survival Analysis for Male and Female Dummies: Meta-analysis of Postmortem Human Subject Tests

Objective: Derive lower leg injury risk functions using survival analysis and determine injury reference values (IRV) applicable to human mid-size male and small-size female anthropometries by conducting a meta-analysis of experimental data from different studies under axial impact loading to the foot–ankle–leg complex.

Methods: Specimen-specific dynamic peak force, age, total body mass, and injury data were obtained from tests conducted by applying the external load to the dorsal surface of the foot of postmortem human subject (PMHS) foot–ankle–leg preparations. Calcaneus and/or tibia injuries, alone or in combination and with/without involvement of adjacent articular complexes, were included in the injury group. Injury and noninjury tests were included. Maximum axial loads recorded by a load cell attached to the proximal end of the preparation were used. Data were analyzed by treating force as the primary variable. Age was considered as the covariate. Data were censored based on the number of tests conducted on each specimen and whether it remained intact or sustained injury; that is, right, left, and interval censoring. The best fits from different distributions were based on the Akaike information criterion; mean and plus and minus 95% confidence intervals were obtained; and normalized confidence interval sizes (quality indices) were determined at 5, 10, 25, and 50% risk levels. The normalization was based on the mean curve. Using human-equivalent age as 45 years, data were normalized and risk curves were developed for the 50th and 5th percentile human size of the dummies.

Results: Out of the available 114 tests (76 fracture and 38 no injury) from 5 groups of experiments, survival analysis was carried out using 3 groups consisting of 62 tests (35 fracture and 27 no injury). Peak forces associated with 4 specific risk levels at 25, 45, and 65 years of age are given along with probability curves (mean and plus and minus 95% confidence intervals) for PMHS and normalized data applicable to male and female dummies. Quality indices increased (less tightness-of-fit) with decreasing age and risk level for all age groups and these data are given for all chosen risk levels.

Conclusions: These PMHS-based probability distributions at different ages using information from different groups of researchers constituting the largest body of data can be used as human tolerances to lower leg injury from axial loading. Decreasing quality indices (increasing index value) at lower probabilities suggest the need for additional tests. The anthropometry-specific mid-size male and small-size female mean human risk curves along with plus and minus 95% confidence intervals from survival analysis and associated IRV data can be used as a first step in studies aimed at advancing occupant safety in automotive and other environments.     

Status of air pollution caused by coal washery projects in India

The importance of coal washeries in India is growing as local coals have a high ash content. At present, there are 23 coal washeries with an annual rated input of 45 Million Tonnes. During the various operations in washeries, large amounts of dusts and gaseous pollutants are generated. Four coal washery projects were surveyed to study their air pollution characteristics. Air monitoring stations were set up in local industrial, residential and sensitive areas and air pollution samples were collected along with micro-meteorological data. Diurnal variations of SPM, SO₂ NO_x and CO are discussed. SPM concentrations were found to exceed the permissible limits at all locations. SO₂ and NO_x were also found to exceed the permissible limit in residential and sensitive areas. It was observed that about 50% of the dust particles were less than 10 µ in diameter. Benzene soluble matter in SPM ranged from 45–62%.     

Toxicity of organic mixtures saturated in water to Daphnia magna. Effect of compositional changes

The toxicity of aqueous solutions saturated with mixtures of hydrophobic organic liquids is contrasted to that of solutions prepared from solids. Data for a variety of mixtures are presented and are related to the solubilities of the components. It is shown that in the absence of biological interactive effects, the toxicity of a component in a saturated mixture of liquids will be equal to or less than that of a corresponding solution of its most toxic component. In contrast, for solutions derived from a mixture of solids, the toxicity will equal or exceed that of a corresponding saturated solution of its most toxic component, and will tend to increase with the complexity of the mixture.     

Nanocarrier-mediated co-delivery systems for lung cancer therapy: recent developments and prospects

Environmental Chemistry Letters - Research has recently focused on combinational therapy using nanocarriers to overcome the obstacles associated with conventional therapy of lung cancer. The...     

Impact of Fly Ash from Coal-Fired Power Stations in Delhi, with Particular Reference to Metal Contamination

Indraprastha Power Station (IPP Stn) and Rajghat Power House (RPH), owned by Delhi Electric Supply Undertaking, are both coal-fired power stations located on Ring Road in New Delhi. Ash content of the coal used ranges between 38–47%. The ash is collected in electrostatic precipitators which have an efficiency of 99.3% (IPP station), and 99.7% (RPH). There are instances of major dust pollution around the power stations from fly ash dispersal. The main method of disposal of fly ash from the power stations is by mixing with water, the resultant slurry is pumped through pipes to ash disposal ponds. The supernatant from these ponds is discharged into River Yamuna. Field studies have revealed large quantities of fly ash being deposited into the river. Local populations of Eichhornia crassipes have reduced dramatically between 1987–1995, with a marked reduction in the year 1994–1995. Field studies, conducted in January, 1995 have investigated the impact of fly ash dispersal in the Delhi region with particular reference to metal contamination. Elemental concentrations for a range of elements are determined by ICP-AES in fly ash and top soils along four transects from the power stations up to a distance of 8 km. The effects of fly ash leachates from the ash settling ponds on the river are determined by analyzing river overbank soils and vegetation for their elemental contents. It is concluded that fly ash dispersal from the stacks are a source of alkali, alkaline-earth and to some extent heavy metals in soils in the vicinity of the power stations, and enrichment of elements in river overbank soils are a result of discharge of fly ash leachates from ash disposal ponds. However, the impact from both these sources of metal contamination is not large enough to give cause for concern. Marked reduction in populations of Eichhornia crassipes downstream of the river where it receives leachates from the ash disposal ponds are attributed to turbidity of the ash pond leachates and metal toxicity. Elemental enrichment in the floodplain soils, as a result of fly ash particle deposition during monsoons, may enhance the horticultural value of these soils as is shown by a healthy cultivated crop of Brassica juncea.     

Effect of pH on the fate of fenazaquin in soil and water under laboratory-simulated condition

The persistence of fenazaquin (4-t-butylphenylethyl quinazolin-4-yl ether) was studied in three different soils, namely, Gangetic alluvial (pH 6.9), laterite (pH 5.3), and terai (pH 5.1) soil and in water at three different pH values (4.0, 7.0, and 9.2) under laboratory-simulated condition and samples were analyzed upto 60 days at regular intervals. Fenazaquin was applied at 5 and 10 µg g^?1 for each soil and at 0.2 and 0.4 µg mL^?1 to each water sample. Dissipation of fenazaquin in soil and water followed first-order kinetics irrespective of any treatments. The half-life of fenazaquin was found in the range of 47–64 days in soils and 3.49–37.6 days in water irrespective of dose. The persistence of fenazaquin in soil significantly increased in the order of Gangetic alluvial soil (pH 6.9) > laterite soil (pH 5.3) > terai soil (pH 5.1), whereas in water the trend of persistence was pH 9.2 ≥ pH 7.0 > pH 4.0. The dissipation of fenazaquin in soil and water was found to be dependent on pH irrespective of doses.     

Arsenic-induced health crisis in peri-urban Moyna and Ardebok villages, West Bengal, India: an exposure assessment study

Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people worldwide. This study aimed to determine the degree of severity of As exposure from drinking water in peri-urban Moyna and Ardebok villages, West Bengal, India. Arsenic concentrations in hair, nail and urine samp les of the individuals were determined. Arsenical dermatosis, keratosis and melanosis were investigated through medical evaluation. We have evaluated the association between As exposure from drinking water, and keratosis and melanosis outcomes. The results showed that 82.7?% of the sampled tube wells contain As concentrations above 10?μg/L, while 57.7?% contain As concentrations above 50?μg/L. The hair, nail and urine As concentrations were positively correlated with As concentrations in drinking water. In our study population, we observed a strong association between As concentrations ranging 51-99?μg/L and keratosis and melanosis outcomes, although the probability decreases at higher concentration ranges perhaps due to switching away from the use of As-contaminated tube wells for drinking and cooking purposes. High As concentrations in hair, nail and urine were observed to be associated with the age of the study population. The level of As concentrations in hair, nail and urine samples of the study population indicated the degree of severity of As exposure in the study region.