Volatile organic compound concentrations and their health risks in various workplace microenvironments

Abstract

Volatile organic compounds (VOCs) are some of the most important pollutants that have adverse effects on human health. In this study, simultaneous indoor and outdoor air samples were collected from four types of microenvironments (restaurants, photocopy centers, dry cleaners, and auto paint shops) in Kocaeli, Turkey in both winter and summer. Twenty-four VOCs were detected using gas chromatography and a flame ionization detector. The aim of the study was to determine the VOC concentrations in various workplaces and investigate associated health risks. Results show that the highest mean total VOC concentrations are in auto paint shops (14,066 µg/m³ in winter, 3441 µg/m³ in summer) followed by dry cleaners, restaurants, and photocopy centers. Total cancer risk was approximately 310 times greater than the acceptable limit in auto paint shops, 44 times greater in restaurants, 42 times greater in dry cleaners, and 17 times greater in photocopy centers. Total hazard quotients were also greater than the acceptable limit in all microenvironments.     

Thermodynamic,Equilibrium and Kinetic Study of the Biosorption of Basic Blue 41 using Bacillus maceran

Thermodynamic, kinetic and equilibrium studies during the biosorption of Basic blue 41(BB 41) from aqueous solution using Bacillus macerans were carried out with a focus on pH, contact time, temperature, biomass dosage and initial dye concentration. The maximum adsorption capacity was found to be 89.2 mg/g under optimal conditions of pH (10.0) and temperature (25 °C). The biosorption rates obtained were consistent with the pseudo‐second order kinetic models. The equilibrium data were analyzed using linearized forms of Langmuir and Freundlich isotherms, and the Langmuir isotherm was found to provide the best correlation of the experimental data for the biosorption of BB 41. The equilibrium time for the removal of BB 41 by the biomass was attained within 90 min. Thermodynamic parameters such as free energy (<$>\Delta G<$>), enthalpy (<$>\Delta H<$>), and entropy (<$>\Delta S<$>) were also calculated. The results indicate that biosorption is spontaneous and exothermic in nature. The negative value of entropy confirms the decreased randomness at the solid‐liquid interface during the adsorption of BB 41 onto Bacillus macerans.     

L’ipséité : son importance en psychopathologie

This paper aims at showing the fecundity of the notion of ipseity or self in the domain of psychopathology. The notions of subject or ego which have been used since Descartes to describe the being of man have led to think it on the model of a substantial and unalterable being. Contemporary philosophy, especially with Heidegger, has on the contrary elaborated a quite other conception of man as an essentially temporal and relational being. What constitutes fundamentally the being of man is not the presence of an invariable nucleus of personality, but it is on the contrary the relations that he is able to establish with the world and the others which defines it in return. The notion of self defines therefore the reflexive character of the being of man. As Paul Ricceur also shows, the identity of the human being is fundamentally a narrative identity, i.e. an identity that constitutes itself through the hazards of a history. What is deeply altered in the different forms of mental diseases is precisely this openness and receptivity that defines the self. What has therefore to be restored by means of therapy is the capacity of the human being to constitute himself as a self in time and to open itself to the unforseeable character of what happens to him.     

Synthesis and DNA-cleaving activity of a series of substituted arenediazonium ions

We investigated the reactions of substituted aryl radicals and aryl cations derived from arenediazonium ions and their ability to cause cleavage of supercoiled DNA and their tendency toward free radical or cation formation in the presence and absent of copper (I) chloride. It was found that the substituted arenediazonium salts can cleave supercoiled DNA to the open circular form II DNA and linear form III DNA. Results methodical studies indicate that both carbon-centered radicals and aryl cations participate in the cleavage pathways.     

Woody plant composition and diversity of urban green spaces in Istanbul,Turkey

Abstract

The high urbanization rate of Istanbul in response to rapid population decreased the size and amount of green spaces. Thereby, every green space types are of vital importance in terms of conservation of urban biodiversity. In this study, it was aimed to compare woody species composition of main green space types consist of artificial and natural sites. Botanical gardens had the highest diversity followed by gardens. Residential areas showed to be important in terms of shrub (52%) and evergreen species (58%), which are mostly exotics (71%). The ratio of the invasive plants in the composition was higher in parks, which contain highway greenings and public gardens. Since the most tree species used in public green areas of Istanbul were mostly same with the species used in European cities, all of the green space categories having varied composition must be considered as interconnected habitat patches in urban planning.     

Dual hydrolysis model of the slowly biodegradable substrate in activated sludge systems

Experimental assessment of the hydrolysis rate coefficients for both domestic sewage and a number of industrial wastewaters was performed with emphasis on two different hydrolysis mechanisms associated with the readily and slowly hydrolyzable COD fractions. The adopted dual hydrolysis model was justified on the basis of significantly different rate constants. The hydrolysis rate of particulate COD occurred at such a slow rate that would significantly interfere with endogenous decay. © Rapid Science Ltd. 1998