Evaluation of exposure to the airborne asbestos in an asbestos cement sheet manufacturing industry in Iran

Iran imports nearly 55,000 tons of Chrysotile asbestos per year and asbestos cement (AC) plants contribute nearly 94% of the total national usage. In the present study, airborne asbestos concentrations during AC sheet manufacturing were measured. The fiber type and its chemical composition were also evaluated by scanning electron microscopy (SEM), with energy-dispersive X-ray analysis. Airborne total fiber concentrations of 45 personal samples were analyzed by phase contrast microscopy. The results have highlighted that 15.5% of samples exceed the threshold limit value (TLV) established the American Conference of Governmental Industrial Hygienists, which is 0.1 fiber per milliliter (f/ml). Personal monitoring of asbestos fiber levels indicated a ranged from 0.02?±?0.01 to 0.16?±?0.03 f/ml. The geometrical mean was 0.05?±?1.36 f/ml, which is considerably lower than the TLV. SEM data demonstrate that the fibrous particles consisted, approximately, of Chrysotile (55.89%) and amphiboles (44.11%). We conclude that the industrial consumption of imported Chrysotile asbestos is responsible for the high airborne amphibole asbestos levels in the AC sheet industry. More research is needed to improve characterization of occupational exposures by fiber size and concentration in a variety of industries.     

Safety Climate and Prediction of Ergonomic Behavior

One of the most important ways to prevent accidents is to consider safety climate or culture. Moreover, some studies suggest that behavior contributes to 86%-96% of all injuries. This cross-sectional study took place in an Iranian petrochemical company in 2010. Vinodkumar and Bhasi’s safety climate questionnaire and an ergonomic behavior sampling checklist were the data collection tools. Cronbach’s a for questionnaire reliability was .928. With reference to the results of a pilot study, a sample of 1755 was determined for behavior sampling. We used principal component analysis (PCA) to derive the coefficient of paths in the path model and the Anderson-Rabin method to calculate factor scores. The results showed that safety climate was an effective predictor of ergonomic behavior (p < .01). They also showed the importance of decreasing the number of workers with negative safety climate. Moreover, it is necessary to promote workers’ ergonomic behaviors in the workplace.     

Effects of Logged and Unlogged Forest Patches on Avifaunal Diversity

In the Hyrcanian forests of northern Iran, reduced-impact silviculture systems, (single-tree and group-tree selection) were applied over a large area, which generated different local habitat structures. The aim of this study was to assess the differences between treated and untreated areas of forest and their effect on avian richness, abundance and diversity (R.A.D). Birds were surveyed during the breeding season in 2009 by 100-point counts, equally distributed in the treated and untreated area. Avian R.A.D was significantly different and higher in the untreated area. Generally, forestry practices cause noticeable changes in canopy percentage, tree composition, snags and shrub number. Treated forest habitats in the area of study had a much more developed understory, fewer snags and fewer large diameter trees. The results highlighted the importance of forest maturity and showed that preventing silvicultural disturbances may not be the best solution for conserving and enhancing biodiversity. Rather, methods such as selective cutting seem an appropriate and sustainable way of forest management. It is suggested that forests should be managed to conserve structural elements which create favorable habitat for bird species, preventing future species losses due to logging practices.     

An experimental study on usage of plastic oil and B20 algae biodiesel blend as substitute fuel to diesel engine

Usage of plastics has been ever increasing and now poses a tremendous threat to the environment. Millions of tons of plastics are produced annually worldwide, and the waste products have become a common feature at overflowing bins and landfills. The process of converting waste plastic into value-added fuels finds a feasible solution for recycling of plastics. Thus, two universal problems such as problems of waste plastic management and problems of fuel shortage are being tackled simultaneously. Converting waste plastics into fuel holds great promise for both the environmental and economic scenarios. In order to carry out the study on plastic wastes, the pyrolysis process was used. Pyrolysis runs without oxygen and in high temperature of about 250–300 °C. The fuel obtained from plastics is blended with B20 algae oil, which is a biodiesel obtained from microalgae. For conducting the various experiments, a 10-HP single-cylinder four-stroke direct-injection water-cooled diesel engine is employed. The engine is made to run at 1500 rpm and the load is varied gradually from 0 to 100 %. The performance, emission and combustion characteristics are observed. The BTE was observed to be higher with respect to diesel for plastic-biodiesel blend and biodiesel blend by 15.7 and 12.9 %, respectively, at full load. For plastic-biodiesel blend, the emission of UBHC and CO decreases with a slight increase in NO _x as compared to diesel. It reveals that fuel properties are comparable with petroleum products. Also, the process of converting plastic waste to fuel has now turned the problems into an opportunity to make wealth from waste.     

The implementation of data reconciliation for evaluating a full-scale petrochemical wastewater treatment plant

Data reconciliation and mass balance analysis were conducted for the first time to improve the data obtained from a petrochemical wastewater treatment plant (WWTP), and the results were applied to evaluate the performance of the plant. Daily average values for 209 days from the inlet and outlet of the plant obtained from WWTP documentation center along with the results of four sampling runs in this work were used for data reconciliation and performance evaluation of the plant. Results showed that standard deviation and relative errors in the balanced data of each measurement decreased, especially for the process wastewater from 24.5 to 8.6 % for flow and 24.5 to 1.5 % for chemical oxygen demand (COD). The errors of measured data were −137 m³/day (−4.41 %) and 281 kg/day (7.92 %) for flow and COD, respectively. According to the balanced data, the removal rates of COD and 5-day biological oxygen demand (BOD₅) through the aeration unit were equal to 37 and 46 %, respectively. In addition, the COD and BOD₅ concentrations were reduced by about 61.9 % (2137 kg/day) and 78.1 % (1976 kg/day), respectively, prior to the biological process. At the same time, the removal rates of benzene, toluene, and styrene were 56, 38, and 69 %, respectively. The results revealed that about 40 % of influent benzene (75.5 kg/day) is emitted to the ambient air at the overhead of the equalization basin. It can be concluded that the volatilization of organic compounds is the basic mechanism for the removal of volatile organic compounds (VOCs) and it corresponds to the main part of total COD removal from the WWTP.

     

Ecological and agriculture impacts of bakery yeast wastewater use on weed communities and crops in an arid environment

Environmental Science and Pollution Research - The goal of this study was to evaluate the impact of using yeast wastewater (YW) on weed communities. The study showed that all ecological parameters...     

Design and Characterization of PVA–Methacrylic Acid Based Smart Polymeric System for Controlled Release of Metoprolol

In the present work covalently crosslinked smart polymeric system of hydrogel based on poly vinyl alcohol (PVA) and methacrylic acid (MA) was designed by free radical polymerization with different compositions using glyoxal (40 % water solution) as crosslinker. It was observed that swelling of hydrogel had a pronounced enhancing effect on increasing the concentration of MA due to availability of more ionized carboxylic groups of MA but produced an opposite effect on increasing the concentration of glyoxal owing to less porous structure. As far as PVA is concerned, swelling did not show significant effect on increasing the concentration of PVA. Hydrophilic polymer PVA rich in hydroxyl group pertained to be highly interactive with water. It was examined that the release of metoprolol tartrate decreased with increased concentration of glyoxal, but increased with increase in concentration of MA. PVA/MA hydrogel was characterized by Fourier transform infrared spectroscopy and X-ray diffraction to study the structure and crystallinity of hydrogel respectively. Morphology was studied through scanning electron microscopy. Furthermore differential scanning calorimetry and thermogravimetric analysis were also performed to characterize thermal stability. It may be concluded that the mechanism of drug release was mainly non-Fickian diffusion.