Concentrations of heavy metals and aquatic macrophytes of Govind Ballabh Pant Sagar an anthropogenic lake affected by coal mining effluent

Five heavy metals Cu, Cd, Mn, Pb and Hg were found in high concentration from three sampling sites located in Asia’s largest anthropogenic lake Govind Ballabh Pant GBP Sagar. Concentrations of these heavy metals were measured in Water, bottom sediment and in different parts of the aquatic macrophytes collected from the reservoir. Plants collected from the lake were Eichhornia crassipes, Azolla pinnata, Lemna minor, Spirodela polyrrhiza, Potamogeton pectinatus, Marsilea quadrifolia, Pistia stratiotes, Ipomea aquqtica, Potamogeton crispus, Hydrilla verticillata and Aponogeton natans. These plants have shown the high concentrations of Cu, Cd, Mn, Pb and Hg in their different parts due to bioaccumulation. In general plant roots exhibited higher concentrations of heavy metals than corresponding sediments. A comparison between different morphological tissues of the sampled plants reveled the metal concentration in following order roots > leaves. Analyses of bottom sediment indicated the higher concentrations of Cd, Mn, Cu and Pb. Strong positive correlations were obtained between the metals in water and in plants as well as between metal in sediment and in plants. Indicating the potential of these plants for pollution monitoring of these metals.     

Residual behavior of quizalofop ethyl on onion (Allium cepa L.)

Quizalofop ethyl, a phenoxy propionate herbicide, is used for postemergence control of annual and perennial grass weeds in broad-leaved crops in India. The experiments were designed to study the dissipation kinetics of quizalofop ethyl on onion for two seasons. A simple, rapid, and sensitive method for estimation of quizalofop ethyl residues in onion and soil was developed and validated. The recoveries of quizalofop ethyl residues from onion and soil at different spiking level range from 84.81 to 92.68 %. The limit of quantification of this method was found to be 0.01 μg g^?1. The risk assessment through consumption of the onion in comparison to its acceptable daily intake which is an important parameter for the safety of the consumer was also evaluated. Standardized methodology supported by recovery studies was adopted to estimate residues of quizalofop ethyl on onion and soil. The average initial deposits of quizalofop ethyl on onion were observed to be 0.25 and 0.33 mg kg^?1, following single application of the herbicide at 50 g active ingredient (a.i.) ha^?1 during 2009 and 2010, respectively. The half-life values (T _1/2) of quizalofop ethyl on onion crop were worked out to be 0.85 and 0.79 days, respectively, during 2009 and 2010. At harvest time, the residues of quizalofop ethyl on onion and soil were found to be below the determination limit of 0.01 mg kg^?1 following single application of the herbicide at 50 and 100 g a.i. ha^?1 for both the periods.     

Spatial 3D distribution of soil organic carbon under different land use types

Soil organic carbon (SOC) has been assessed in three dimension (3D) in several studies, but little is known about the combined effects of land use and soil depth on SOC stocks in semi-arid areas. This paper investigates the 3D distribution of SOC to a depth of 1 m in a 4600-ha area in southeastern Iran with different land uses under the irrigated farming (IF), dry farming (DF), orchards (Or), range plants on the Gachsaran formation (RaG), and range plants on a quaternary formation (RaQ). Predictions were made using the artificial neural networks (ANNs), regression trees (RTs), and spline functions with auxiliary covariates derived from a digital elevation model (DEM), the Landsat 8 imagery, and land use types. Correlation analysis showed that the main predictors for SOC in the topsoil were covariates derived from the imagery; however, for the lower depths, covariates derived from both the DEM and imagery were important. ANNs showed more efficiency than did RTs in predicting SOC. The results showed that 3D distribution of SOC was significantly affected by land use types. SOC stocks of soils under Or and IF were significantly higher than those under DF, RaG, and RaQ. The SOC below 30 cm accounted for about 59% of the total soil stock. Results showed that depth functions combined with digital soil mapping techniques provide a promising approach to evaluate 3D SOC distribution under different land uses in semi-arid regions and could be used to assess changes in time to determine appropriate management strategies.     

Cellular uptake and mutagenic potential of metal oxide nanoparticles in bacterial cells

Extensive production and consumption of nanomaterials such as ZnO and TiO₂ has increased their release and disposal into the environment. The accumulation of nanoparticles (NPs) in ecosystem is likely to pose threat to non-specific targets such as bacteria. The present study explored the effect of ZnO and TiO₂ NPs in a model bacterium, Salmonella typhimurium. The uptake of ZnO and TiO₂ bare NPs in nano range without agglomeration was observed in S. typhimurium. TEM analysis demonstrated the internalization and uniform distribution of NPs inside the cells. Flow cytometry data also demonstrates that both ZnO and TiO₂ NPs were significantly internalized in the S. typhimurium cells in a concentration dependent manner. A significant increase in uptake was observed in the S. typhimurium treated even with 8 and 80 ng mL⁻¹ of ZnO and TiO₂ NPs with S9 after 60 min, possibly the formation of micelles or protein coat facilitated entry of NPs. These NPs exhibited weak mutagenic potential in S. typhimurium strains TA98, TA1537 and Escherichia coli (WP2uvrA) of Ames test underscoring the possible carcinogenic potential similar to certain mutagenic chemicals. Our study reiterates the need for re-evaluating environmental toxicity of ZnO and TiO₂ NPs presumably considered safe in environment.     

Development of controlled release formulations of carbofuran and imidacloprid and their bioefficacy evaluation against aphid, Aphis gossypii and leafhopper, Amrasca biguttula biguttula Ishida on potato crop

Controlled release (CR) formulations of carbofuran and imidacloprid were prepared employing polyvinyl chloride and carboxymethyl cellulose (CMC) and their bioefficacy was evaluated against the aphid, Aphis gossypii and leafhopper, Amrasca biguttula biguttula Ishida on potato crop. The CR formulations of carbofuran and imidacloprid provided better or equal control of the pests than commercial formulations. CMC-based formulation provided a superior control of both the pests. The Imida-CMC, which showed the lowest population of leaf hopper (10.50 leafhopper/100 cl), provided significantly superior control among all treatments after 35 days after germination (DAG). The residue of carbofuran and imidacloprid in potato tuber and soils were not detectable at the time of harvesting in any one of the formulations.     

Preparation of Cellulose Nanocrystals Using an Ionic Liquid

In this paper cellulose nanocrystals were prepared by treating microcrystalline cellulose with 1-butyl-3-methylimidazolium hydrogen sulphate ionic liquid. Cellulose nanocrystals, after separation from ionic liquid, were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscopy (FESEM) Transmission Electron Microscope (TEM) and Thermogravimetric analysis. XRD results showed no changes in type of cellulose after the treatment with ionic liquid, however, high crystallinity index was observed in the ionic liquid treated sample. Cellulose nanocrystals, having length around 50–300 nm and diameter around 14–22 nm were observed in the ionic liquid treated sample under FESEM and TEM, and similar patterns of peaks as that of microcrystalline cellulose were observed for cellulose nanocrystals in the FTIR spectra. The thermal stability of the cellulose nanocrystals was measured low as compare to microcrystalline cellulose.     

Hematological, biochemical and ionoregulatory responses of Indian major carp Catla catla during chronic sublethal exposure to inorganic arsenic

In the present study the acute toxicity of arsenic trioxide in fingerlings of Catla catla an Indian major carp was evaluated with renewal bioassay method. The median lethal concentration of arsenic trioxide to the fish C. catla for 96 h was found to be 20.41 ppm (with 95% confidence limits). From this a non-lethal dose of (2.041 ppm; 1/10th of LC 50 96 value) was selected and fingerlings were exposed to 35 d and hematological, biochemical and ionoregulatory responses were studied at days 7, 14, 21, 28 and 35. Arsenic trioxide produced a significant increase in hemoglobin, hematocrit, WBC count, plasma GPT levels and reduction in RBC count, plasma sodium, chloride, potassium, glucose, protein, GOT, LDH levels as compared to the control group. Gill Na⁺/K⁺-ATPase activity was influenced by arsenic trioxide exposure. A biphasic response was noted in the value of MCH and MCV. However the MCHC level was not altered in arsenic trioxide treated fish throughout the study period. Results of the present investigation suggest that arsenic trioxide affects the hematological, biochemical and ionoregulatory parameters of fish and alterations of these parameters can be useful in environmental biomonitoring of arsenic contamination.     

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.     

Health Effects of Air Quality Regulations in Delhi, India

This, the first systematic study, quantifies the health effects of air quality regulations in Delhi, which adopted radical measures to improve air quality, including, for example, the conversion of all commercial vehicles to compressed natural gas (CNG), and the closure of polluting industries in residential areas from 2000 to 2002. Air pollution data, collected at 113 sites (spread across Delhi and its neighboring areas) from July-December 2003, were used to compute exposure at the place of residence of 3,989 subjects. A socio-economic and respiratory health survey was administered in 1,576 households. This survey collected time-use, residence histories, demographic information, and direct measurements of lung function with subjects. The optimal interpolation methods were used to link air pollution and respiratory health data at the place of their residence. Resident histories, in combination with secondary data, were used to impute cumulative exposure prior to the air-quality interventions, and the effects of recent air quality measures on lung function were then evaluated. Three important findings emerge from the analysis. First, the interventions were associated with a significant improvement in respiratory health. Second, the effect of these interventions varied significantly by gender and income. Third, consistent with a causal interpretation of these results, effects were the strongest among those individuals who spend a disproportionate share of their time out-of-doors.