Biodiversity of brackish water amphipods (crustacean) in two estuaries, southeast coast of India

The present study about the gammarid amphipods of Vellar and Uppanar estuaries was performed during two seasons (pre-monsoon and post-monsoon, 2005–2006), respectively, in nine habitats: five in the Vellar estuary and four in the Uppanar estuary. Amphipod samples were collected from sediments, oyster beds, seaweeds, sea grass, and mangroves. A total of 29 species of gammarid amphipods were collected in each area. The surface water temperature ranged from 16°C to 26°C, the salinity from 20 to 32 psu, and the pH between 7.5 and 8.3. Dissolved oxygen ranged from 5.3 to 7.8 ml/l. The maximum abundance of amphipods was observed during the pre-monsoon (July to September) in Vellar mangrove, and it was minimum during the pre-monsoon in Uppanar sea grass. It was found that several physicochemical factors, such as salinity, temperature, dissolved oxygen, pH, and the substrate have a marked effect on the distribution and the relative abundance of amphipods. The ranges of species diversity, richness, dominance, and evenness in the Vellar and Uppanar estuaries were 1.58–4.15, 1.82–5.29, 0–0.11, and 0.96–1, respectively. Using multivariate analyses, in each estuary, it was possible to identify different communities of amphipod species according to their habitats.     

Solid waste characterization,quantification and management practices in developing countries. A case study: Nablus district – Palestine

Solid waste management (SWM) is one of the most challenging issues faced by developing countries that suffer from serious pollution problems caused by the generation of large waste quantities. This paper presents the case study of SWM in the Nablus district – Palestine. Surveys for household residents' and SWM program operators, field investigations, on-site waste measurements and characterizations were conducted. Per capita waste generation rates varied between different localities although trends were similar. Overall, the majority of waste was organic (65.1% by weight), suggesting a strong resource recovery potential in terms of animal feed or compost. Recyclable waste (plastic, paper and card) made up 16.7% by weight the waste composition suggesting an incentive to introduce source separation. Household attitudes complemented the waste characterization study, revealing the main problems faced. SWM operators quoted on the current status, highlighting problems with disposing in unsanitary landfills, ineffective solid waste fees system, increasing solid waste quantities and lacking equipment and experienced personnel. To enhance sustainable SWM, public awareness, funding, expertise, equipment and facilities and other provisions currently lacking or inappropriate must be provided.     

Monitoring trace metals in different tissues of Cyprinus carpio from the Indus River in Pakistan

This replicated 4×2 factorial study investigated the bioaccumulation of selected metals (Mn, Pb, Zn, Hg and Cr) in four tissues (gills, liver, muscle and skin) of common carp (Cyprinus carpio) domiciled in two sites (upstream and downstream) of Indus River in Mianwali district of Pakistan. The data were statistically compared for the main effects of the site and fish organs and their interaction on the bioaccumulation pattern of these metals in fish organs at P?P?相似文献   

Sisal/Carbon Fibre Reinforced Hybrid Composites: Tensile, Flexural and Chemical Resistance Properties

The variation of mechanical properties such as tensile and flexural properties of randomly oriented unsaturated polyester based sisal/carbon fibre reinforced hybrid composites with different fibre weight ratios have been studied. The chemical resistance test of these hybrid composites to various solvents, acids and alkalies were studied. The effect of NaOH treatment of sisal fibres on the tensile, flexural and chemical resistance properties of these sisal/carbon hybrid composites has also been studied. The hybrid composites showed an increase in tensile and flexural properties with increase in the carbon fibre loading. The tensile properties and flexural properties of these hybrid composites have been found to be higher than that of the matrix. Significant improvement in tensile properties and flexural properties of the sisal/carbon hybrid composites has been observed by alkali treatment. The chemical resistance test results showed that these untreated and alkali treated hybrid composites are résistance to all chemicals except carbon tetra chloride. Hand lay-up technique was used for making the composites and tests are carried out by using ASTM methods.     

CIELAB color variables as indicators of compost stability

The composting process of different organic wastes both in laboratory and on a large-scale was characterized using CIELAB color variables to evaluate compost stability for the better application in agriculture. The time courses of the CIELAB variables of composting materials were determined directly from the bottom of a glass petri dish filled with dried and ground samples using a Minolta Color Reader (CR-13) calibrated with clean empty petri dishes placed on a white tile. To compare the proposed method with conventional methods, the same materials were also evaluated using commonly used compost stability evaluation indices. Most of the CIELAB variables of a compost made from a mixture of green tea waste and rice bran reached a plateau after 84 days of composting and showed strong relationships with the commonly used compost stability evaluation indices. The time needed for CIELAB variables, especially the L*and b* values, to stabilize at large-scale composting plants of cattle litter, farmyard manure, kitchen garbage and bark compost, were more or less similar to the times of maturation evaluated by the respective compost producers. The CIELAB color variable offers a new, simple, rapid and inexpensive means of evaluating compost stability and its quality prior to agricultural use.     

Leachate characterization in semi-aerobic and anaerobic sanitary landfills: A comparative study

This study analyzes and compares the results of leachate composition at the semi-aerobic Pulau Burung Landfill Site (PBLS) (unaerated pond and intermittently aerated pond) and the anaerobic Kulim Sanitary Landfill in the northern region of Malaysia. The raw samples were collected and analyzed for twenty parameters. The average values of the parameters such as phenols (1.2, 6.7, and 2.6 mg/L), total nitrogen (448, 1200, and 300 mg/L N-TN), ammonia-N (542, 1568, and 538 mg/L NH₃-N), nitrite (91, 49, and 52 mg/L NO₂^?-N), total phosphorus (21, 17, and 19 mg/L), BOD₅ (83, 243, and 326 mg/L), COD (935, 2345, and 1892 mg/L), BOD₅/COD (0.096,0.1124,0.205%), pH (8.20, 8.28, and 7.76), turbidity (1546, 180, and 1936 Formazin attenuation units (FAU)), and color (3334, 3347, and 4041 Pt Co) for leachate at the semi-aerobic PBLS (unaerated and intermittently aerated) and the anaerobic Kulim Sanitary Landfill were recorded, respectively. The obtained results were compared with previously published data and data from the Malaysia Environmental Quality Act 1974. The results indicated that Pulau Burung leachate was more stabilized compared with Kulim leachate. Furthermore, the aeration process in PBLS has a considerable effect on reducing the concentration of several pollutants. The studied leachate requires treatment to minimize the pollutants to an acceptable level prior to discharge into water courses.     

Simultaneous polarographic determination of 2-nitrophenol and 4-nitrophenol by differential pulse polarography method and support vector regression

A differential pulse polarography (DPP) for the simultaneous determination of 2-nitrophenol and 4-nitrophenol was proposed. It was found that under optimum experimental conditions (pH = 5, scan rate = 5 mV/s, pulse amplitude = −50 mV), 2-nitrophenol and 4-nitrophenol had well-defined polarographic reduction waves with peak potentials at −317 and −406 mV, respectively. In the mixture of two compounds overlapping polarographic peaks were observed. In this study, support vector regression (SVR) was applied to resolve the overlapped polarograms. Furthermore, a comparison was made between the performance of SVR and partial least square (PLS) on data set. The results demonstrated that SVR is a better well-performing alternative for the analysis and modeling of DPP data than the commonly applied PLS technique. The proposed method was used for the determination of 2-nitrophenol and 4-nitrophenol in industrial waste water.     

Production and Purification of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Degrading Enzyme from Streptomyces sp. AF-111

A poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) degrading bacterial strain designated as AF-111 was isolated from sewage sludge sample. The bacterium was identified by 16S rRNA gene sequencing. The results revealed that strain AF-111 showed 99 % similarity with Streptomyces althioticus strain NRRL B-3981 and designated as Streptomyces sp. strain AF-111. An extracellular PHBV depolymerase enzyme was produced under optimized conditions and purified through ammonium sulphate fractionation and column chromatography. The enzyme was purified to homogeneity, indicated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and molecular weight was found to be approximately 51 kDa. Effect of temperature, pH, metal ions and inhibitors on the PHBV depolymerase activity was determined. The enzyme was stable at wide range of temperature (35–55 °C) and pH (6–8). PHBV depolymerase was stable in the presence of different metal ions except iron and zinc which had inhibitory effect on depolymerase activity. Both ethylenediamine teteracetic acid and phenylmethyl sulphonyl fluoride strongly inhibited enzyme activity which indicates that this enzyme belongs to the serine hydrolase family like other polyhydroxyalkanoate depolymerases. The results show that a depolymerase from strain AF-111 can effectively degrade PHBV, therefore, it can be applied in the process of biochemical monomer recycling.     

Phytoremediation of an arsenic-contaminated site using Pteris vittata L. and Pityrogramma calomelanos var. austroamericana: a long-term study

This field study investigated the phytoremediation potential of two arsenic (As) hyperaccumulating fern species, Pityrogramma calomelanos var. austroamericana and Pteris vittata over 27-month duration at a disused As-contaminated cattle-dip site located at Wollongbar, NSW, Australia. Ferns planted in January 2009 were harvested following 10, 22 and 27 months of growth. A detailed soil sampling was undertaken in June 2009 (initial, n?=?42 per plot) and limited sampling in April 2011 (after 27 months, n?=?15 per plot) to measure total and phosphate-extractable As concentrations in soil at 0?-?20-, 20?-?40- and 40?-?60-cm depths. The choice of the limited number of samples was considered sufficient to estimate the changes in soil As concentration following phytoremediation based on a geostatistical model. The average frond dry biomass, As concentration and As uptake were significantly (P??0.05), respectively, by P. vittata. Our results show that phytoremediation time based on observed changes in soil As based on limited sampling is not reliable; hence, it is recommended that the frond As uptake should be considered in order to evaluate the phytoremediation efficiency of the two fern species at the experimental site. Using As uptake of the two fern species, we estimate that with P. calomelanos var. austroamericana it would take 55?-?125 years to decrease mean total As content below the ecological investigation level (20 mg kg(-1)) in the surface and subsurface soils, whereas with P. vittata 143?-?412 years would be required to achieve this target.     

Thermodynamic and kinetic studies of As(V) removal from water by zirconium oxide-coated marine sand

Arsenic contamination of groundwater is a major threat to human beings globally. Among various methods available for arsenic removal, adsorption is fast, inexpensive, selective, accurate, reproducible and eco-friendly in nature. The present paper describes removal of arsenate from water on zirconium oxide-coated sand (novel adsorbent). In the present work, zirconium oxide-coated sand was prepared and characterised by infrared and X-ray diffraction techniques. Batch experiments were performed to optimise different adsorption parameters such as initial arsenate concentration (100–1,000 μg/L), dose (1–8 g/L), pH of the solution (2–14), contact time (15–150 min.), and temperature (20, 30, 35 and 40 °C). The experimental data were analysed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Furthermore, thermodynamic and kinetic parameters were evaluated to know the mode of adsorption between ZrOCMS and As(V). The maximum removal of arsenic, 97 %, was achieved at initial arsenic concentration of 200 μg/L, after 75 min at dosage of 5.0 g/L, pH?7.0 and 27?±?2 °C. For 600 μg/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 μg/g at 35 °C. Kinetic modelling data indicated that adsorption process followed pseudo-second-order kinetics. The mechanism is controlled by liquid film diffusion model. Thermodynamic parameter, ΔH°, was ?57.782, while the values of ΔG° were ?9.460, ?12.183, ?13.343 and ?13.905 kJ/mol at 20, 30, 35 and 40 °C, respectively, suggesting exothermic and spontaneous nature of the process. The change in entropy, ΔS°?=??0.23 kJ/mol indicated that the entropy decreased due to adsorption of arsenate ion onto the solid adsorbent. The results indicated that the reported zirconium oxide-coated marine sand (ZrOCMS) was good adsorbent with 97 % removal capacity at 200 μg/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10 μg/L, and in real situation, this low concentration can be achieved through this adsorbent. Besides, the adsorption capacity showed that this adsorbent may be used for the removal of arsenic from any natural water resource.