Monitoring of Phenol in Wastewater Bioremediation by HPLC

Bioremediation emphasizes the detoxification and destruction of toxic substances by microorganisms. Wastewater obtained from an industrial concern was solvent extracted with methyl alcohol and dichloromethane and analysed by GC/MS. Besides phenol, a large variety of organic compounds were detected. Under controlled laboratory conditions, the wastewater was innoculated with a mixed culture of microorganisms specially selected for their abilities to degrade phenol. Samples were collected at regular intervals from the stirred tank bioreactor and analysed for phenol by reverse phase HPLC with a C18 column. Results shows that from an initial phenol concentration of 987 ppm, slightly more than 50% was destroyed within 163 hours. The dry weight of the microorganisms and the plate count (CFU/ml) shows a steady increase from 0.5238 gms to 0.5355 gms and from 1.1E+9 to 1.94E+13 respectively over the same period. This suggested that the phenol was consumed by the microorganisms as the sole carbon source.     

Diphenyl diselenide attenuates hepatic and hematologic toxicity induced by chlorpyrifos acute exposure in rats

Purpose

In this study, we investigated the effect of diphenyl diselenide [(PhSe)₂] on chlorpyrifos (CPF)-induced hepatic and hematologic toxicity in rats.

Methods

Rats were pre-treated with (PhSe)₂ (5?mg/kg) via the oral route (oral gavage) once a day for 7?days. On the eighth and ninth days, rats were treated with (PhSe)₂ (5?mg/kg) 30?min prior to CPF (50?mg/kg, by subcutaneous route). The aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase activities were determined in plasma of rats. Lipid peroxidation, protein carbonyl, and non-protein thiol levels as well as catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and gluthatione S-transferase activities were determined in livers of rats. Hematological parameters were also determined.

Results

The results showed that CPF caused hepatic oxidative damage, as demonstrated by an increase in lipid peroxidation and protein carbonyl levels which was associated with a decrease in antioxidant defenses. CPF exposure caused a reduction in the leukocyte, indicating hematologic toxicity. (PhSe)₂ was effective in attenuating these toxic effects caused by CPF exposure in rats.

Conclusions

The results indicated that (PhSe)₂ was effective in protecting the hepatic and hematologic toxicity induced by acute CPF exposure in rats.     

In-Process Measurements of Flow Characteristics of Wood Plastic Composites

The flow characteristics of polypropylene filled with high percentages of wood flour (50 and 70 wt%) are investigated at a feasible processing temperature (195 °C). Rotational rheometry in oscillatory mode in conjunction with the Cox–Merz rule is ineffective at this temperature due to insufficient linear viscoelastic region (LVR) size and ease of fibres degradation. An in-line rheometer, directly attached to a single screw extruder, is used to avoid these problems: this method allows measurements in real processing conditions with no LVR issues and with reduced degradation risks. The 70 wt% displays plug flow, thus it has been impossible to obtain the flow curve but only the slip velocity as a function of shear stress. The 50 wt% could be corrected for slip using the Mooney procedure. Comparing the flow curve of this material with the ones of the 30 wt% and the unfilled polypropylene matrix, a single master-curve can be obtained and modelled with a Carreau–Yasuda equation.     

The dynamics of landfill diversion: Economic drivers, policy factors and spatial issues: Evidence from Italy using provincial panel data

Waste disposal is an issue that is becoming increasingly important in policy terms in the European Union, and in Italy, a country showing strong geographical heterogeneity in waste management. This paper analyses the process of decoupling/delinking between economic growth and landfilling trends in a framework where economic, policy, geographical elements and spatial issues are all considered as drivers behind the phenomenon. We exploit an original and very rich provincial panel dataset over 1999–2005 for the 103 Italian provinces. Evidence shows that the observed ‘absolute’ decoupling between economic growth and landfilling is driven by a mix of structural factors. Among the main factors, population density, more than the provincial income level, emerges as a crucial driver: local opportunity costs and landfill externalities matter in shaping waste policies and local commitment to a transition away from landfilling of waste (landfill diversion). However, not only structural factors are relevant. If on the one hand landfill taxes are not a significant driver of the phenomenon, waste management tools, such as separated collection for recycling, and the tariff system connected to waste services, bring about significant effect on the amount of landfilled waste. Moreover, regarding the analysis of spatial interrelations across provinces, we note that the presence of incinerators in nearby provinces increases landfill diversion, due probably to free riding behaviour or intra-provinces ‘agreements’ on waste management; this is not true for nearby landfill sites, that cause for a given province a strong lock in effect. Future research could strengthen the analysis of policy effectiveness at regional level, focusing on policy endogeneity, and the full investigation of spatial correlations in waste disposal performances.