Mineral contents of the head, caudal, central fleshy part, and spinal columns of some fishes

In the experiment, mineral contents of the head, caudal, central fleshy part, and spinal columns of fishes were determined by inductively coupled plasma atomic emission spectrometry. The Ca content of base fleshy part ranged from 1,682 to 5,505 mg/kg. The Ca contents of central fleshy part were found between 104 and 428 mg/kg. This value was found between 5,582 and 7,368 in the spinal column parts. The K content in general ranged from 2,411 (Carassius gibellio) and 4,419 mg/kg (Scomber scombrus). The highest potassium was found on the central fleshy part and ranged between 3,214 and 4,419. The P content was found mostly on the bones and it range between 28,833 and 34,726. The least phosphor amount was found on the central fleshy part. While the Cd content ranges between 0.019 ppm and 0.104 mg/kg, Cr content changed between 1.32 and 4.20 ppm.     

Comparative Investigations on Optimum Polymerization Conditions for the Synthesis of a Sustainable Poly(Lactic Acid)

The development of synthetic biodegradable polymers using solvent free polymerization has a unique potential to be used as sustainable polymers in biomedical applications. The aim of this work was to synthesize and characterize a sustainable class of poly(lactic acid) (PLA) under different operating conditions via direct polycondensation of lactic acid (LA). Several parameters were tested including the absence of solvents and catalysts on the polymerization, in addition to polymerization temperature and time. Polymerization conditions were evaluated using response surface method (RSM) to optimize the impact of temperature, time, and catalyst. Results showed that molecular weight (M_w) of PLA increased with increasing polymerization time. Highest M_w of 28.4 kD with relatively a broad polydispersity 1.9 was achieved at polymerization temperature 170?°C at 24 h in the free solvent polymerization. This led to a relevant inherent viscosity of 0.37 dl/g. FTIR spectra exhibited a disappearance of the characteristic peak of the hydroxyl group in LA at 3482 cm^?1 by increasing the intensity of carbonyl group. The ¹H nuclear magnetic resonance (NMR) exhibited the main chain at 5.22 ppm and the signal of methyl proton at 1.61 ppm as well as a signal at 4.33 and 1.5 assigned to the methane proton next to the terminal hydroxyl group and carboxyl group respectively. Meanwhile, the PLA synthesized with a catalyst [Sn(Oct)₂] in a free solvent demonstrated comparatively high thermal transition properties of glass transition, melting, and crystallinity temperatures of 48, 106, and 158?°C, respectively. These results are of significant interest to further expand the use of PLA in biomedical applications.     

Growth and physiological response of spinach to various lithium concentrations in soil

Environmental Science and Pollution Research - Lithium (Li) exploitation for industrial and domestic use is resulting in a buildup of the element in various environmental components that results in...     

Biogeochemical transformation of greenhouse gas emissions from terrestrial to atmospheric environment and potential feedback to climate forcing

Environmental Science and Pollution Research - Carbon dioxide (CO2) is mainly universal greenhouse gas associated with climate change. However, beyond CO2, some other greenhouse gases (GHGs) like...     

Temperature dependence of gas-phase polycyclic aromatic hydrocarbon and organochlorine pesticide concentrations in Chicago air

The temperature dependence of gas-phase atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides measured in Chicago, IL between June and October 1995 were investigated using plots of the natural logarithm of partial pressures (ln P) vs. reciprocal mean temperatures (1/T). For the eight lowest molecular weight PAHs, temperature dependence was statistically significant (at the 95% confidence level) and temperature accounted for 23–49% of the variability in gas-phase concentrations. The relatively higher slopes for most of the PAHs suggested that volatilization from local sources and short-range transport influenced their concentrations. For pesticides, temperature dependence was statistically significant for DDD and for trans-nonachlor (at the 95% and 90% confidence levels), and was not statistically significant for the other five compounds (2–18% of the variability in their gas-phase concentrations). The relatively lower slopes for individual pesticides suggested that they have mostly non-urban and distant sources.Results of back trajectory analyses suggested that the region, southwest of Chicago, might be an important local or regional source sector for PAHs and organochlorine pesticides. No statistically significant relationship was observed between wind speed and PAH or pesticide concentrations. None of the variables (temperature, wind speed, wind direction, local and regional sources) could fully explain the variation in their concentrations measured in Chicago, therefore, this variation can be attributed to the combined effect of those factors.     

Adaptation and validation of QuEChERS method for the analysis of trifluralin in wind-eroded soil

This study was carried out to develop and validate a reliable analytical procedure for trifluralin analysis in wind-eroded sediments. Soil sediments trapped in BEST sediment traps were subjected to QuEChERS extraction method, incorporating a simple simultaneous cleanup step, followed by trifluralin analysis with GC-ECD. Results revealed that QuEChERS method offered a potential alternative technique for pesticide extraction from soil samples. The validity of analytical method was performed by the method-performance criteria such as, recovery, LOD, LOQ repeatability, precision, and all found to be within the required limits. It was also observed in this study that herbicide concentrations in the wind-eroded sediment did not vary with the time and trap height. Trifluralin concentrations of surface soil after four erosion events were higher (626.05 μg/kg) than wind-eroded soil (450.08 μg/kg).     

Assessing the Impact of Carbon Tax Differentiation in the European Union

To what extent do the welfare costs associated with the implementation of the Burden Sharing Agreement in the European Union depend on sectoral allocation of emissions rights? What are the prospects for strategic climate policy to favor domestic production? This paper attempts to answer those questions using a CGE model featuring a detailed representation of the European economies. First, numerical simulations show that equalizing marginal abatement costs across domestic sectors greatly reduces the burden of the emissions constraint but also that other allocations may be preferable for some countries because of pre-existing tax distortions. Second, we show that the effect of a single country's attempt to undertake a strategic policy to limit impacts on its domestic energy-intensive industries has mixed effects. Exempting energy-intensive industries from the reduction program is a costly solution to maintain the international competitiveness of these industries; a tax-cum-subsidy approach is shown to be better than exemption policy to sustain exports. The welfare impact either policy – exemption or subsidy – on other European countries is likely to be small because of general equilibrium effects.     

External benefits of environmental regulation: Resource recovery and the utilisation of effluents

Summary Since 1977, stringent environmental regulation has been progressively imposed on Malaysia's most polluting industry, the palm oil mills. The impact of the regulation on international trade and producer welfare has been quite small compared to the relative benefits to society in terms of changes in the levels of dissolved oxygen in the industrial effluents. External benefits from pollution abatement have been derived. This paper presents a preliminary evaluation of the derived benefits which have a long- term potential of recycling valuable resources while maintaining competitiveness in the international palm oil trade.Dr Khalid Abdul Rahim is a member of faculty in the Department of Natural Resource Economics at the Universiti Pertanian Malaysia. Wan Mustafa Wan Ali is a research assistant in the Department. This paper is based on part of the "Intensification of Research in Priority Areas" (IRPA) project 1991–95, funded by the Government of Malaysia.