Vapour pressures, aqueous solubilities, Henry's Law constants, and octanol/water partition coefficients of a series of mixed halogenated dimethyl bipyrroles

Basic physical-chemical properties of five bromine and chlorine containing mixed halogenated dimethyl bipyrroles (HDBPs) were determined using established methods. Subcooled liquid vapour pressures (P(o)(L,25)), aqueous solubilities (S(w,25)), and octanol/water partition coefficients (K(ow)) were determined using the gas chromatography-retention time, generator column, and slow-stirring methods, respectively. Henry's Law constants (H25) were estimated using experimentally-derived P(o)(L) and S(w,25) data. Values of all four properties were generally similar to those reported for other polyhalogenated aromatic compounds [P(o)(L,25) = (7.55-191) x 10(-6) Pa; S(w,25) = (1.0-1.9) x 10(-5) g/l; log K(ow) = 6.4-6.7; H25 = 0.0020-0.14 Pa m3/mol]. The effect of replacing a chlorine with a bromine atom significantly decreased P(o)(L,25) (log P(o)(L,25) = -0.4197 (# bromine atoms) - 2.643, p<0.01) and H25 (log H25 = -0.508 (# bromine atoms) + 0.394, p<0.02). There were no significant effects of bromine/chlorine substitution on S(w,25) or K(ow). A simple Level I equilibrium partitioning model predicted the environmental behaviour of HDBPs to be similar to a tetrabrominated diphenyl ether. Only slight differences in behaviour amongst HDBP congeners were predicted since substitution of a bromine for a chlorine (Cl/Br substitution) atom had less effect than H/Cl or H/Br substitution on P(o)(L,25), S(w,25), H25, and K(ow).     

Sublethal effects of monocrotophos on locomotor behavior and gill architecture of the mosquito fish, Gambusia affinis

Subacute studies of monocrotophos [Dimethyl (E)-1-methyl-2-(methyl-carbamoyl) vinyl phosphate] on mosquito fish, Gambusia affinis, were carried out in vivo for 24 days to assess the locomotor behavior, structural integrity of gill, and targeted enzyme acetylcholinesterase (AChE, EC: 3.1.1.7) interactions. Monocrotophos (MCP) can be rated as moderately toxic to G. affinis, with a median lethal concentration (LC(50)) of 20.49 +/- 2.45 mgL(-1). The fish exposed to sublethal concentration of LC(10) (7.74 mgL(-1)) were under stress and altered their locomotor behavior, such as distance traveled per unit time (m min(-1)) and swimming speed (cm sec(-1)) with respect to the length of exposure. Inhibition in the activity of brain AChE and deformities in the primary and secondary lamellae of gill may have resulted in failure of exchange of gases. The maximum inhibition of 95% of AChE activity was observed on days 20 and 24.Morphological aberrations in the gills were also studied during exposure to the sublethal concentration of monocrotophos for a period ranging from 8 to 24 days. The extent of damage in gill was dependent on the duration of exposure. The findings revealed that inhibition in brain AChE activity and structural alteration in gill were responsible for altering the locomotor behavior of exposed fish.     

Effect of arsenite on certain aspects of protein metabolism in fresh water teleost, Tilapia mossambica (Peters)

The sublethal toxicity of sodium arsenite on protein metabolism was investigated in teleost fish, Tilalpia mossambica at the end of 24, 48, 72 and 96 h of exposure. Total protein content, free amino acid content and activities of the enzymes aspartate amino transferase (AAT) and alanine amino transferase (ALAT) in liver, gill, brain and muscle exhibited significant (P<0.05) alterations throughout the investigation in relation to that of control. It is suggested that the fish is able to respond to the stressful situations by gearing up the metabolic activity as revealed by the elevated protein, amino acid content and the activities of AAT and ALAT.     

Dominant features in three-dimensional turbulence structure: comparison of non-uniform accelerating and decelerating flows

The results are presented from an experimental study to investigate three-dimensional turbulence structure profiles, including turbulence intensity and Reynolds stress, of different non-uniform open channel flows over smooth bed in subcritical flow regime. In the analysis, the uniform flow profiles have been used to compare with those of the non-uniform flows to investigate their time-averaged spatial flow turbulence structure characteristics. The measured non-uniform velocity profiles are used to verify the von Karman constant κ and to estimate sets of log-law integration constant B_r and wake parameter П, where their findings are also compared with values from previous studies. From κ, B_r and П findings, it has been found that the log-wake law can sufficiently represent the non-uniform flow in its non-modified form, and all κ, B_r and П follow universal rules for different bed roughness conditions. The non-uniform flow experiments also show that both the turbulence intensity and Reynolds stress are governed well by exponential pressure gradient parameter β equations. Their exponential constants are described by quadratic functions in the investigated β range. Through this experimental study, it has been observed that the decelerating flow shows higher empirical constants, in both the turbulence intensity and Reynolds stress compared to the accelerating flow. The decelerating flow also has stronger dominance to determine the flow non-uniformity, because it presents higher Reynolds stress profile than uniform flow, whereas the accelerating flow does not.     

Heavy metal contamination in river water and sediments of the Swarnamukhi River Basin,India: risk assessment and environmental implications

The concentration of heavy metals was analyzed each of 20 river water, suspended sediments and bed sediments along the stretch of Swarnamukhi River Basin. River water is not contaminated with heavy metals except Fe and Mn. Contamination factor in sediments shows considerable to very high degree contamination with Cr, Cu, Pb and Zn. The sources of these metals could be residential wastes, sewer outfall, fertilizers, pesticides (M-45 + carbondine) and traffic activities apart from natural weathering of granitic rocks present in the basin area. Principal component analyses indicate the interaction between metals in different media. The comparison of metals (Cu, Pb and Zn) in bed sediments of Swarnamukhi River with the Indian and world averages indicates that the values obtained in the basin are above the Indian averages and far below to the world averages. Average shale values and sediment quality guidelines point toward the enrichment and contamination of Cu, Cr, Pb and Zn to several fold leading to eco-toxicological risks in basin.     

Seasonal variation in male-female competition,cooperation and selfish hoarding in a monogamous songbird

Both cooperation and conflict between the sexes are commonplace in monogamous mating systems. However, little is known about how cooperation and competition varies seasonally in monogamous species that maintain permanent territories. We presented territorial pairs of male and female New Zealand robins (Petroica australis) with a large supply of insect prey at monthly intervals for 2 years. Behavioural observations after food presentation were then made to quantify seasonal and sexual differences in aggressive interactions over prey, prey acquisition rates, mate provisioning, offspring provisioning, selfish food hoarding and cache retrieval. Data were used to evaluate sex-specific behavioural strategies of mediating competition for food. Results showed that males aggressively excluded females from experimental food sources year-round. Females only accessed food sources when males left them unattended. Consequently, females acquired fewer prey than males. After controlling for differences in prey acquisition, both sexes consumed similar amounts of prey in the non-breeding season. Even though males aggressively excluded females from accessing food sources directly, males fed large amounts of prey to females during the breeding season. Both sexes provisioned young at similar rates. Males cached less prey than females in the breeding season but more prey than females in the non-breeding season. Females showed similar caching intensities year-round. Although males tried to defend their hoards, females frequently retrieved male-made caches. Overall, results showed that although New Zealand robins cooperate to raise offspring during the breeding season, conflict between the sexes occurs year-round. Males and females display different behavioural strategies to gain access to experimental food sources, which appear to lessen male–female competition for food and evenly distribute food resources between the sexes.     

Biodegradable Composites Containing Chicken Feathers as Matrix and Jute Fibers as Reinforcement

This research demonstrates that chicken feathers can be used as matrix to develop completely biodegradable composites with properties similar to that of composites having polypropylene (PP) as matrix. Feathers are ubiquitous and inexpensive but have limited industrial applications. Feathers have been preferably used for composite applications due to their low density and presence of hollow structures that facilitate sound absorption. However, previous approaches on using feathers for composites have used the whole feather or the feather fractions as reinforcement with synthetic polymers as matrix resulting in partially degradable composites. In addition, the hydrophilicity of the feathers and hydrophobicity of the synthetic matrix results in poor compatibility and therefore less than optimum properties. Although it has been shown that feathers can be made thermoplastic and suitable to develop films and other thermoplastics, there are no reports on using feathers as matrix for composites. In this research, chicken feathers were used as matrix and jute fibers as reinforcement to develop completely biodegradable composites. Tensile, flexural and acoustic properties of the feather-jute composites were compared to PP-jute composites. Utilizing feathers as matrix could enable us to develop low cost 100 % biodegradable composites containing feathers or other biopolymers as the reinforcement.     

Processability and Biodegradability Evaluation of Composites from Poly(butylene succinate) (PBS) Bioplastic and Biofuel Co-products from Ontario

This study investigates the processability and biodegradability of composite bioplastic materials. Biocomposites were processed using twin-screw compounding of the bioplastic poly(butylene succinate) (PBS) with bio-based fillers derived from co-products of biofuel production. An extensive biodegradability evaluation was conducted on each biocomposite material, as well as the base materials, using respirometric testing to analyze the conversion of organic carbon into carbon dioxide. This evaluation revealed that the presence of meal-based fillers in the biocomposites increased the rate of biodegradation of the matrix polymer, degrading at a faster pace than both the pure PBS polymer and the switchgrass (SG) composite. This degradation was further confirmed using FT-IR and thermal analysis of the material structure before and after biodegradation. The increased biodegradation rate is attributed to the high concentration of proteins in the meal-based composites, which enhanced the hydrolytic biodegradation of the material and facilitated micro-organism growth. The SG-based composite degraded slower than the pure polymer due to its lignin content, which degrades via a different mechanism than the polymer, and slowed the biodegradation process.     

Are South Indian farmers adaptable to global change? A case in an Andhra Pradesh catchment basin

Global changes are already having an impact on South Indian farmers. Climate change is affecting the agricultural sector since it is dependent on climatic conditions and water resource availability. The impacts tend to be greater in semi-arid hard rock areas with few water resources. Furthermore, South India area is experiencing a profound agrarian crisis, which is linked, among others, to debt and credit problems. The study reported in this paper aims to develop a methodology to compare and rank farmers according to their ability to adapt to global change. The definition of adaptive capacity is based on a livelihood assets approach. Indicators are evaluated through individual surveys among farmers, then, weighted using the analytic hierarchy process and aggregated via compromise programming. The result is a standardized score measuring the distance of each farmer from an ideal adaptive capacity. Farmers are ranked according to this distance, which allows a comparison of their relative ability to adapt. At the basin scale, it shows that the geographic position of farmers is a significant factor in adaptation performance. The proximity of an administrative center contributes to an increase of their adaptive capacity. Small farming areas limit the adaptive capacities of marginal and small farmers while the largest farmers are constrained by economic factors such as large loans. These study findings offer interesting indications on the variability of farmers’ weaknesses and are bringing a better understanding of the causes of poor performance.     

Immobilization and volume reduction of heavy metals in municipal solid waste fly ash using nano-size calcium and iron-dispersed reagent

This study was conducted to examine the synthesis and application of novel nano-size calcium/iron-based composite material as an immobilizing and separation treatment of the heavy metals in fly ash from municipal solid waste incineration. After grinding with nano-Fe/Ca/CaO and with nano-Fe/Ca/CaO/[PO₄], approximately 30 wt% and 25 wt% of magnetic fraction fly ash were separated. The highest amount of entrapped heavy metals was found in the lowest weight of the magnetically separated fly ash fraction (i.e., 91% in 25% of treated fly ash). Heavy metals in the magnetic or nonmagnetic fly ash fractions were about 98% and 100% immobilized, respectively. Additionally, scanning electron microscopy combined with energy-dispersive X-ray spectrometry (SEM-EDS) observations indicate that the main fraction of enclosed/bound materials on treated fly ash includes Ca/PO₄-associated crystalline complexes. After nano-Fe/Ca/CaO/[PO₄] treatment, the heavy metal concentrations in the fly ash leachate were much lower than the Japan standard regulatory limit for hazardous waste landfills. These results appear to be extremely promising. The addition of a nano-Fe/Ca/CaO/PO₄ mixture with simple grinding technique is potentially applicable for the remediation and volume reduction of fly ash contaminated by heavy metals.

Implications: After grinding with nano-Fe/Ca/CaO and nano-Fe/Ca/CaO/[PO₄], approximately 30 wt% and 25 wt% of magnetic fraction fly ash were separated. The highest amount of entrapped heavy metals was found in the lowest weight of the magnetically separated fly ash fraction (i.e., 91% in 25% of treated fly ash), whereas heavy metals either in the magnetic or nonmagnetic fly ash fractions were about 98% and 100% immobilized. These results appear to be very promising, and the addition of nano-Fe/Ca/CaO/PO₄ mixture with simple grinding technique may be considered potentially applicable for the remediation and volume reduction of contaminated fly ash by heavy metals.