Environmental studies on river water quality with reference to suitability for agricultural purposes: Mahanadi river estuarine system, India – a case study

Hydrochemistry of surface water (pH, specific conductance, total dissolved solids, sulfate, chloride, nitrate, bicarbonate, hardness, calcium, magnesium, sodium, potassium) in the Mahanadi river estuarine system, India was used to assess the quality of water for agricultural purposes. The samples were studied for 31 different stations during six different seasons in the years 2001-2003. Chemical data were used for mathematical calculations (SAR, Na%, RSC, potential salinity, permeability index, Kelly's index, magnesium hazard, osmotic pressure and salt index) for better understanding the suitability river water quality for agricultural purposes. The river water is free from nitrate-nitrogen hazard and has much less osmotic pressure and RSC values. Further there is no complete precipitation of calcium and magnesium in the study area. The results revealed that waters of some polluted stations like Sambalpur down (D/s of Sambalpur town) and Kathjodi (Cuttack) down (D/s of Cuttack town) are unsuitable up to some extent, where as it is quite unsuitable in case of estuarine samples during the pre-monsoon and post-monsoon seasons. The results were verified by USSL and Wilcox diagrams, which show all the fresh water zone samples (low-medium salinity with low sodium) of the study area are in the 'Excellent to good' category and are suitable to irrigate all soils for semi-tolerant and tolerant as well as sensitive crops.     

Glutathione and cysteine biosynthesis in two varieties of Abelmoschus esculentus in response to mine spoil

The extent of accumulation of some heavy metals and glutathione and cysteine levels in the roots and aerial plant parts in two genotypically different varieties of A. esculentus (KS404 and BO2) exposed to mine spoil were investigated. Glutathione (GSH) level in both the varieties on control sites increased from basal level to 155.15 nmol g(-1) dry weight (d.wt.), almost 1.5 fold on 30 day and attained a plateau within 60 day Mine spoil exposure of both the varieties decreased glutathione 1.13 fold (89.2 nmol g(-1) dry weight) during 60 day from its basal level. GSH concentration in shoots of these varieties increased accompanying growth contrary to roots where it finally declined 2 fold. Cysteine content in control plants increased 2 fold (31.6 nmol g(-1) dry weight) on 30 day and finally declined 1.38 fold (22.35 nmol g(-1) dry weight, at 60 day). Both the varieties, when exposed to mine spoil, showed enhanced cysteine content almost 2 fold during 30 day (50.95 nmol g(-1) dry weight) but failed to increase further Forshoots in both the varieties challenged with mine spoil, cysteine maxima reached late (15.2 nmol g(-1) dry weight, at 40 day) relative to control but the levels declined subsequently (11.85 nmol g(-l) dry weight). Contrary to GSH, cysteine content in roots of both the varieties responded positively to mine spoil as apparent from the 2.23 fold increase during 30 d than basal level although it lowered to a level of 12.85 nmol g(-1) dry weight finally at 60 day. Both the varieties accumulated almost maximum level of selected cations (Fe > Mn> Zn> Cu > Ni) during 30 day, but BO2 variety was significantly superior in this regard. Invariably high accumulation of such cations in roots over shoots indicated accumulation, retention or restricted translocation from root to shoot. The metal share of the edible part was just 6% of the plant load. Thus, present work reflects a genotypic differences in metal accumulation and that affected the major non-enzymatic traits or synthesis of sulthydryl compounds as well. The present results also indicate that metal tolerance is in part associated with anti-oxidant system activity.     

A Bayesian approach for understanding the role of ship speed in whale-ship encounters

Mandatory or voluntary reductions in ship speed are a common management strategy for reducing deleterious encounters between large ships and large whales. This has produced strong resistance from shipping and marine transportation entities, in part because very few studies have empirically demonstrated whether or to what degree ship speed influences ship-whale encounters. Here we present the results of four years of humpback whale sightings made by observers aboard cruise ships in Alaska, representing 380 cruises and 891 ship-whale encounters. Encounters occurred at distances from 21 m to 1000 m (x = 567 m) with 61 encounters (7%) occurring between 200 m and 100 m, and 19 encounters (2%) within 100 m. Encounters were spatially aggregated and highly variable across all ship speeds. Nevertheless a Bayesian change-point model found that the relationship between whale distance and ship speed changed at 11.8 knots (6.1 m/s) with whales encountering ships, on average, 114 m closer when ship speeds were above 11.8 knots. Binning encounter distances by 1-knot speed increments revealed a clear decrease in encounter distance with increasing ship speed over the range of 7-17 knots (3.6-8.7 m/s). Our results are the first to demonstrate that speed influences the encounter distance between large ships and large whales. Assuming that the closer ships come to whales the more likely they are to be struck, our results suggest that reduced ship speed may be an effective management action in reducing the probability of a collision.     

Differential fate of metabolism of a disperse dye by microorganisms Galactomyces geotrichum and Brevibacillus laterosporus and their consortium GG-BL

The present work aims to evaluate Brown 3 REL degrading potential of developed microbial consortium GG-BL using two microbial cultures, Galactomyces geotrichum MTCC 1360 (GG) and Brevibacillus laterosporus MTCC 2298 (BL). Microbial consortium GG-BL showed 100% decolorization of a dye Brown 3 REL, while individually G. geotrichum MTCC 1360 and B. laterosporus MTCC 2298 showed 26% and 86% decolorization under aerobic condition (shaking) respectively. Measurements of biochemical oxygen demand (BOD) (76%) and chemical oxygen demand (COD) (68%) were done after decolorization by consortium GG-BL. No induction in activities of oxidoreductive enzymes found in G. geotrichum while B. laterosporus showed induction of veratryl alcohol oxidase, Nicotineamide adenine dinucleotide-dichlorophenol indophenol (NADH-DCIP) reductase and riboflavin reductase indicating their role in dye metabolism. Consortium GG-BL showed induction in the activities of laccase, veratryl alcohol oxidase, tyrosinase, NADH-DCIP reductase and riboflavin reductase. Two different sets of induced enzymes from G. geotrichum and B. laterosporus work together in consortium GG-BL resulting in faster degradation of dye. The degradation of Brown 3 REL was analyzed using high performance thin layer chromatography (HPTLC), high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FT-IR) and gas chromatography mass spectroscopy (GC-MS). Phytotoxicity study revealed that metabolites formed after degradation was significantly less toxic in nature.     

Possible cause of inhibition of seed germination in two rice cultivars by heavy metals Pb2+ and Hg2+

Seeds of two rice cultivars (Oryza sativa) cv. PR-116 and Pant Dhan-12 subjected to heavy metal lead (Pb²⁺) and mercury (Hg²⁺) exposure showed an inhibition in germination percentage, shoot and root length, and lower fresh and dry weight after 7 days. Both Pb²⁺ and Hg²⁺ inhibited the solubilization process of starch due to reduction in α-amylase activity, which is also evident from greater starch content and reduced soluble carbohydrate content of endosperms of treated seeds of the two cultivars. Mercury was more tolerated by Pant Dhan-12 when grown under in vitro culture medium containing 2% sucrose. The inhibitory effect of Pb²⁺ on embryo growth was not only abolished but also accelerated by 2% sucrose. The inhibitory effect, however, was not significantly blocked in Hg²⁺-treated embryos grown in vitro in sucrose containing medium. Embryos did not grow normally in a medium devoid of sucrose in either case. Data indicated that Pb²⁺ inhibited germination and seedling growth by impairing the solubilization of endosperm starch without markedly affecting the embryo, while Hg²⁺ inhibited germination and seedling growth by damaging the embryo itself.     

Effect of TiC Nanoparticles Reinforcement in Coir Fiber Based Bio/Synthetic Epoxy Hybrid Composites: Mechanical and Thermal Characteristics

Journal of Polymers and the Environment - The present investigation was performed to study the effect of titanium carbide (TiC) nanoparticles and coir fiber as hybrid reinforcements on the...     

Development of a variable configuration cascade impactor for aerosol size distribution measurement

In atmospheric aerosol studies, it is often required to use two different impactors, namely, the normal pressure and the low-pressure impactor, to measure the mass-size distribution over a wide size range. From the perspective of rendering the system compact for such measurements, it may be more advantageous to combine the two features in a single instrument. In an effort towards exploring this option, a variable configuration cascade impactor (VCCI) comprising of 7 normal pressure and 4 low-pressure stages has been designed and developed. In configuration-1, it operates as a low-pressure impactor, with a sampling flow rate of 10 L min^?1 and classifies the particles from 0.1 to 21 μm in eleven size classes. In configuration-2, it operates as a normal pressure impactor, with a sampling flow rate of 45 L min^?1, and classifies the particles from 0.53 to 10 μm in seven size classes. As part of performance evaluation of the system, the deposit patterns and the integral performance have been studied. For integral performance, a comparative mass-size distribution measurement between VCCI and standard Andersen impactor was carried out. Its performance was also evaluated against the GRIMM Scanning Mobility Particle Sizer (SMPS) in the common size range of both these instruments and against GRIMM Optical Particle Counter (OPC). In addition to this, VCCI was evaluated for its performance in the PM_x configuration obtained by removing a few of the impactor stages sequentially and measuring corresponding size distribution for every stage removed. Changes in the distribution parameters due to spillover of the deposits of previous stage to remaining stages were within 10%. This variation is well within the generally accepted value for all environmental measurement related applications.     

Assessment of habitat quality with relation to fish assemblages in an impacted river of the Ganges basin, northern India

In this work, we examined water-quality assessment in relation to fish assemblage of Gomti River, a large tributary of the Ganges River basin in northern India. Principal component analysis was performed for 18 environmental variables which produced three axes that cumulatively explained 60.23% of the environmental variation in sites. Fifteen variables (fine substrate fine gravel, coarse gravel, cobble, sand substrate water flow, conductivity, TDS, total hardness, temperature, dissolved oxygen, pH, and overhanging vegetation) had high loadings on at least one of the principal component axes interpreted. The canonical correspondence analysis was used to establish the relationship between important fish species and environmental variables. Species were distributed within four groups with respect to the significant habitat characteristics. The Pearson correlation coefficient was calculated between the water-quality parameters. We concluded that the level of species richness is mostly dependent on abiotic factors like temperature, dissolved oxygen, TDS, conductivity, depth, pH, and water current in the Gomti River, of the Ganges basin.     

Toxicity of various anions associated with methoxyethyl methyl imidazolium-based ionic liquids on Clostridium sp

We investigated the effects on the growth of the anaerobic bacterium, Clostridium sp., of the ionic liquid, 1-methoxyethyl-3-methyl imidazolium [MOEMIM]⁺, derived from imidazolium cation and paired with one of a variety of counter-ions, viz., tetrafluoroborate [BF₄]^-, hexafluorophosphate [PF₆]^-_, trifluoroacetate [CF₃COO]^-, bis(trifluoromethane)sulfonamide [Tf₂N]^-, methane sulfonate [OMS], and 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF₄]. These anions, in association with [MOEMIM]⁺ lowered the growth rate of the bacterium, showing the following trend: [Tf₂N]^- ≧ [PF₆]^- > [BF₄]^- > [CF₃COO]^- > [OMS]⁻. Anions incorporating fluorine were more toxic than those without it, and their toxicity rose with an increase in the number of fluorine atoms. Also, [MOEMIM]⁺[BF₄]^- was less toxic than [BMIM]⁺[BF₄]^-, probably due to the presence of a methoxyethyl functional group integrated in the cation side chain.     

Ammonia concentrations and modeling of inorganic particulate matter in the vicinity of an egg production facility in Southeastern USA

Ammonia (NH₃) is an important base gas and can react with acidic species to form atmospheric aerosols. Due to the rapid growth of poultry and swine production in the North Carolina Coastal Plain, atmospheric NH₃ concentrations across the region have subsequently increased. Ammonia concentrations and inorganic particulate matter (PM) at four ambient stations in the vicinity of an egg production facility were measured for 1 year using PM_2.5 speciation samplers with honeycomb denuders and ion chromatography (IC). Meanwhile, concentrations of NH₃ and inorganic PM in one of the egg production houses were also simultaneously measured using a gas analyzer for NH₃ and the filter pack plus IC method for inorganic PM. An equilibrium model-ISORROPIA II was applied to predict the behavior of inorganic aerosols in response to precursor gas concentrations and environmental parameters. Average ambient NH₃ concentrations varied from 10.0 to 27.0 μg/m³, and they were negatively correlated with the distances from the ambient location to the nearest egg production house exhausts. Ambient NH₃ concentrations were higher in warm seasons than in cold seasons. Measured NH₃ concentrations agreed well with ISORROPIA II model predictions at all sampling stations. For the ambient stations, there was a good agreement in particle phase NH₄ ⁺ between the model simulation and observations. For the in-house station, the model simulation was applied to correct the overestimation of particle phase NH₄ ⁺ due to gas phase NH₃ breaking through the denuders. Changes in SO₄ ^2?, NO₃ ^?, and Cl^? yield proportional changes in inorganic PM mass. Due to the abundance of NH₃ gas in the vicinity area of the monitored farm, changes in NH₃ concentrations had a small effect on inorganic PM mass. Aerosol equilibrium modeling may be used to assess the influence of precursor gas concentrations on inorganic PM formation when the measurements for some species are unavailable.