Prediction of future disposal of end-of-life refrigerators containing CFC-11

The objective of this study was to predict the number of refrigerators containing CFC-11 blown isolation foam and the amount of CFC-11 banked in these refrigerators. By using a Weibull-based survival function, the number of CFC-11 containing and still-functioning refrigerators was estimated to be approximately 1.6 million in 2013 in Turkey. In order to determine the amount of CFC-11 in the isolation foam of these refrigerators, polyurethane (PU) foam samples were taken from a refrigerator manufactured in 1993 and the quantity of CFC-11 was analyzed by a GC-MS. It was determined that 113–195 mg CFC-11/g PU remains in the PU foam depending on the location such as door, sides, top and bottom. Knowing that a mid-sized refrigerator contains 4 kg PU on average, the total amount of PU foam to be disposed of is 6344 tons when the CFC-11 containing refrigerators in Turkey become obsolete in the near future. Furthermore, 717–1237 tons of CFC-11 are expected to be banked in the PU foam of these refrigerators which will exert an equivalent amount of ozone depleting potential (ODP). In addition, the global warming potential will vary between 3.4 and 5.9 million tons of CO₂.     

Assessment of environmental radioactivity for Batman, Turkey

The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil, building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity concentrations of the natural radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) and a fission product (¹³⁷Cs) were 35 ± 8, 25 ± 10, 274 ± 167 and 12 ± 7 Bq kg^???1, respectively, in the soil samples. The concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the selected building materials ranged from 18 to 48 Bq kg^???1, 8 to 49 Bq kg^???1 and 68 to 477 Bq kg^???1, respectively. All the calculated radium equivalent (Ra_eq) activity values of the building material samples are lower than the limit of 370 Bq kg^???1, equivalent to a γ-dose of 1.5 mSv year^???1. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in tap waters collected from the study area were determined with mean specific activity concentrations of 42 ± 15, 35 ± 9 and 524 ± 190 mBq L^???1, respectively. Indoor radon measurements were made at 95 dwellings in Batman using a CR-39 detector. The radon concentration levels were found to vary from 23 to 145 Bq m^???3. The arithmetic mean of the measured radon concentration levels was found to be 84 Bq m^???3 with a standard deviation value of 23 Bq m^???3. The measurement results obtained in this study did not significantly differ from those taken in other parts of the country. The data generated in this study can be used to determine whether the Batman province is in a normal or high background radiation area and provides a valuable database for future estimations of the impact of radioactive pollution.     

Fatty acid composition of marine macroalgae from the Black Sea and Dardanelles

The fatty acid (FA) composition was determined in 14 species of marine macroalgae belonging to the Chlorophyta, Phaeophyta and Rhodophyta, which were collected from ?ile in the Black Sea and Kepez in the Dardanelles. Generally, polyunsaturated FAs and monounsaturated FAs were major components (50–77%). Total saturated FAs ranged from 22% to 50%, with 16?:?0 as the most abundant saturate (32–38%). Two samples of Cystoseira barbata collected from a different station had some differences from each other in their contents of 18?:?2n-6 and 18?:?3n-3 and in the 18?:?2n-6/20?:?4n-6 ratios. Green algal species had a significantly higher proportion of unsaturated FAs and a significantly lower proportion of saturated FAs than the red and brown algae. The amount of n-3 FAs was significantly higher in Ulva rigita, Chaetomorpha linum, Enteromorpha linza and Gracilaria verrucosa (8.88, 6.44, 5.31 and 5.24, respectively).     

Retro-techno-economic evaluation of acetic acid production using cotton stalk as feedstock

In value-added chemical industries, use of agricultural wastes as raw materials remains to be a major challenge in commercialization due to lack of competitiveness with respect to petrochemical processes. This work presents the techno-economic analysis of a novel bioprocessing plant converting 356,400 MT/year cotton stalks into 147,000 MT/year acetic acid. A production scheme integrating lignin separation with the main bioconversion stages has been proposed. Techno-economic assessment was performed through economic feasibility and retro-techno-economic analysis (RTEA) methods. The RTEA method has been extended to include the estimation of research and development funding for improving economic feasibility. Carbon offset of the proposed technology has been estimated and carbon credit results have been incorporated into the economic feasibility metrics.     

Influence of water hardness on the bioavailability and toxicity of linear alkylbenzene sulphonate (LAS)

In the present work, the influence of Ca²⁺ concentration on the toxicity of single cut linear alkylbenzene sulfonate (LAS) homologues was studied. Precipitation boundary diagrams for each homologue were obtained, indicating turbid and clear zones depending on the LAS and Ca²⁺ concentrations. The separation between transparent and turbid zones is given by the so-called precipitation line. LAS toxicity to Daphnia magna was determined at concentrations close to this precipitation line. It was observed that when Ca(LAS)₂ precipitation progresses, LAS bioavailability decreases for test animals, and the toxicity diminishes even at high nominal LAS concentrations. According to the “free ion activity model” (FIAM), the toxicity of a given chemical compound is mainly due to the ionic species (Ca²⁺–LAS⁻) and not due to the precipitated molecule, Ca(LAS)₂. The significance of the present study is in connection with the assessment of LAS sorption/precipitation studies in soils and sediments, where in situ toxicity is strongly influenced by Ca²⁺/Mg²⁺ ions, according to the results presented in this work.     

Simulation of arsenic partitioning in tributaries to drinking water resevoirs

Arsenic released by bottom sediments was determined by experiments in which the sediments were artificially re-suspended using a particle entrainment simulator (PES) to simulate river conditions. Sediment cores were collected from various tributaries to drinking water reservoirs in Connecticut spiked with arsenic, and run in the PES at simulated bed-flow shear stresses from 0.0 to 0.6 N/m². Under equilibrium conditions, the dissolved fraction of arsenic was found to range from 8.3 to 22.1 μg/l, which in most cases exceeded EPA Maximum Contaminant Level (MCL) of 10 μg/l. Experimental results from these simulations have shown that bed-flow shear stress causes an increased concentration of dissolved arsenic, most notably at shear stresses of 0.4, 0.5, and 0.6 N/m². For the solid phase under equilibrium, the concentrations of arsenic ranged between 71 and 275 mg/kg. The average concentration of arsenic on the solid phase as well as partitioning coefficient values (K _p) were highest at initial shear stress. This was attributed to the higher fraction of colloidal material and finer organic particles in the suspended solid mixture. Particles of such nature proved to have higher affinity to arsenic. K _p values were determined from PES data and were found to range from 4,687 to 24,090 l/kg. However, on a mass load basis, the amount of arsenic found in suspended sediment increased with the increase of shear stress. Similarly, the amount of arsenic in the solid phase increased significantly for sites with high Volatile Organic Carbon (VOC) content. Because of the influence of Total Suspended Solids (TSS) and VOC concentrations on K _p, the use of the PES is more appropriate in obtaining K _p values that would be found under real stream conditions when compared to the traditional way of measuring K _p using a jar study technique.     

Temporal analysis of coastal erosion in Turkey: a case study Karasu coastal region

Coastal erosion may be caused by natural causes as well as human factors. Karasu town of the city of Sakarya in Turkey which is a touristic region on the Black Sea coast has been experienced a drastic coastal erosion. In recent years, this erosion reached the threatening dimensions for the structures in the settlement. According to the temporal analyses of Landsat satellite images, the maximum erosion on the coastline was detected 100 m between 1987–2013. The results of the study show that the harbour construct on the Karasu coast has the major impact on this event. The secondary factor is that the amount of the sediment carried by the Sakarya River was decreased in time due to different reasons. To prevent the coastal erosion, a series of offshore breakwaters were planned after the failed application of groins on the coastline. In this study, temporal changes of the coastline are investigated by the Landsat satellite data and land surveys, possible reasons of the erosion are discussed and the solutions are proposed regarding the coastal structures.     

Assessment of dermal exposure to benzene and toluene in shoe manufacturing by activated carbon cloth patches

OBJECTIVES: The aim of this investigation was to use activated carbon cloth (ACC) patches to study the probability and extent of dermal exposure to benzene and toluene in a shoe factory. METHODS: Inhalation and dermal exposure loading were measured simultaneously in 70 subjects on multiple days resulting in 113 observations. Dermal exposure loading was assessed by ACC patches attached to likely exposed skin areas (e.g. the palm of the hand and abdomen). A control patch at the chest and an organic vapor monitor (OVM) were used to adjust the hand and abdomen patches for the contribution from the air through passive absorption of benzene and toluene on the ACC patches. Systemic exposure was assessed by quantification of unmetabolized benzene (UBz) and toluene (UTol) in urine. RESULTS: Mean air concentrations for the study population were 1.5 and 7.5 ppm for benzene and toluene, respectively. Iterative regression analyses between the control patch, OVM and the dermal patches showed that only a small proportion of the ACC patches at the hand had likely benzene (n = 4; mean 133 microg cm(-2) h(-1)) or toluene (n = 5; mean 256 microg cm(-2) h(-1)) contamination. Positive patches were exclusively observed among subjects performing the task of gluing. Significant dermal exposure loading to the abdomen was detected only for toluene (n = 2; mean 235 microg cm(-2) h(-1)). No relation was found between having a positive hand or abdomen ACC patch and UBz or UTol levels. In contrast a strong association was found between air levels of benzene (p = 0.0016) and toluene (p < 0.0001) and their respective urinary levels. CONCLUSIONS: ACC patches are shown to be a useful technique for quantifying the probability of dermal exposure to organic solvents and to provide estimates of the potential contribution of the dermal pathway to systemic exposure. Using ACC patches we show that dermal exposure to benzene and toluene in a shoe manufacturing factory is probably rare, and when it occurred exposures were relatively low and did not significantly contribute to systemic exposure.