A study of the dental solid waste produced in a school of dentistry in Turkey

Dental wastes are regulated under medical waste control regulations in most countries. Even though the quantity of hazardous wastes in dental solid wastes is a small proportion, there is still cross infection risk and potential danger for environment associated with mismanaged wastes. For this reason, knowledge of waste composition and development of proper management alternatives are necessary. In this study, the composition of solid wastes coming from eight clinics of the dental school of a University hospital in Turkey is examined. Although the waste has some variations between the two samplings, the general picture is such that the major components remain pretty much the same (in terms of %) for a fixed clinic. The composition of waste changes from one clinic to the other as expected. However, one can deduce from the data obtained that at about 35%, rubber gloves constitute close to the half of the total solid waste in almost all the clinics. Other major component is paper forming approximately 30% of the solid waste. In general, total waste coming from the clinics is related with the number of procedures conducted on patients at the clinics. Only a small fraction of the waste is hazardous indicating that at Hacettepe University School of Dentistry, hazardous waste collection rules are obeyed in most of the times.     

Influence of Downstream Control and Limited Depth on Flow Hydrodynamics of Impinging Buoyant Jets

Much study has been performed on the mixing properties of submerged, turbulent buoyant jets. It is safe to say that the problem of estimating dilution rates in vertical buoyant jets spreading in an `infinitely deep' ambient water has been more than adequately resolved by previous researchers. However, the majority of environmental applications involve discharges into ambient waters of finite depths in which a bounding surface serves to re-direct the impinging buoyant jet horizontally into a radial spreading layer. Previous research indicates that this impinging jet undergoes additional mixing before buoyancy stabilizes vertical mixing and confines the spreading layer to the vicinity of the bounding surface. Unfortunately, the conceptualization and subsequent mathematical modeling of this additional mixing phenomenon is surrounded by considerable amount of disagreement between researchers. The purpose of this study is to provide, by means of velocity and concentration profile measurements, independent experimental evidence for the existence of a critical flow state immediately downstream of the active mixing zone in the horizontally flowing, radial flow that forms after impingement. It is further shown that this critical flow state must be expressed in terms of a composite Froude Number that takes into account the possibility of a non-zero exchange layer flow. Finally, the influence of the presence of a sill-like topographic downstream control on the criticality of the radial flow immediately downstream of the active mixing zone is also investigated.     

Speciation of chromium in 12 agricultural soils from Turkey

The objective of the study was to speciate and to evaluate various soil Cr species in relation to soil properties. Surface soil samples were taken from outskirts of the Cr factory and applied a sequential extraction procedure. Extracts analyzed in atomic absorption spectrophotometry (AAS). Chromium was partitioned into exchangeable Cr, Cr bound to carbonate, Fe-Mn oxide, and organic matter, and residual Cr. The most common form of chromium was in the residual form, followed by the organic form. Very low concentrations of Cr were found in the exchangeable and carbonate forms. Mean values of the extractable forms of Cr, expressed in percentages of total soil contents were: 0.94% exchangeable, 0.80% carbonates, 2.13% oxides, 7.08% organics and 89.81% residual. Multiple regression analysis of analytical data revealed that soil pH, contents of organic matter and calcium carbonate were the most important factor controlling the distribution of Cr forms determined.     

Modeling of real scale waste activated sludge anaerobic digestion process by Anaerobic Digestion Model 1 (ADM1)

In this study, real-scale wastewater treatment plant (Hurma WWTP) sludge anaerobic digestion process was modeled by Anaerobic Digestion Model (ADM1) with the purpose of generating the data to understand the process better by contributing to the prediction of the process operational conditions and process performance, which will be a base for future anaerobic sludge stabilization process investments.

Real-scale anaerobic sludge digestion process data was evaluated in terms of known process and state variables and also process yields. Average VS removal yield, methane production yield, and methane production rate values of the anaerobic sludge digestion unit were calculated as 46.4%, 0.49 m³CH₄/kg VS_removed, and 0.33 m³ CH₄/m³day, respectively. In this study, ADM1 was intended to predict the behavior of real-scale anaerobic digester processing sewage sludge under dynamic conditions. To estimate the variables of real-scale sludge anaerobic digestion process with high accuracy and to provide high model prediction performance, values of the four parameters (disintegration rate constant, carbohydrate hydrolysis rate constant, protein hydrolysis rate constant, and lipid hydrolysis rate constant) that have strong effects on structured ADM1 were estimated by using the parameter estimation module in Aquasim program and their values were found as 0.101, 10, 10, and 9.99, respectively. When the numbers of kinetic parameters with the processes included in ADM1 along with the dynamic and non-linear structure of the real scale anaerobic digestion were taken into consideration, model simulations were in good agreement with measured results of the biogas flow rate, methane flow rate, pH, total alkalinity, and volatile fatty acids.     

渭干河灌区地表水与地下水水量及水盐平衡对比分析

地下水经常不断地参与自然界的水循环,通过从外界获得水量而得到补给,特别是对我们南疆大型灌区而言。地表水是地下水主要补给来源,径流过程中,地表水由补给处输送到排泄处,在水量交换运移过程中,径流同时伴随着盐分的交换与运移,这就是地表水和地下水的循环过程。地表水的补给,径流与排泄决定着地下水的水量与水质在空间和时间的变化,只有对地下水补给、排泄和径流建立起清晰的概念,才有可能正确地分析与评价地下水资源,采取有效的措施,因此据我们目前的各种资料来分析地表水与地下水对比,很有根据和价值。     

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.     

Bioremediation of heavy metal contaminated medium using Lemna minor,Daphnia magna and their consortium

Single, dual and triple mixtures of totally seven different mixture combinations of the metals Al, Ba and Fe were examined in Lemna minor (L) culture, Daphnia magna (D) culture and in a consortium culture consisting of L. minor and D. magna. In this study: (a) differences in removed metal proportions at the end of 24 and 48?h, (b) differences in removed metal amounts due to cultures, (c) differences in the removed proportions of a metal in distinct mediums and (d) removal correlation of the metals due to cultures were investigated. The study results showed that among the metals Al, Ba and Fe, Al has the most toxic effect on organisms involved in this study. Although similar toxicity results of Al and Fe on test groups were observed, Ba gave different toxicity results on test groups. An overview of the bioremediation results indicates that L. minor removes the metals Al and Fe more successfully than Ba. Different mixture combinations of metals performed dissimilar removal results in the same cultures. According to the correlations analysis for the metals Ba and Fe, a high correlation was recorded between the consortium group and test groups containing only D. magna, r?=?0.88, r?=?0.91, respectively.     

Heavy metal accumulation in water, sediments and fishes of Nallihan Bird Paradise, Turkey

The accumulation of some heavy metals such as Pb, Cd, Cu and Ni was determined in water sediment and fish samples (Albumus escherichii, Cyprinus carpio and Silurus glanis) collected from Nallihan Bird Paradise (NBP) and its vicinity (Sariyar Dam). The results showed that these metals are found widespread throughout the study area, but metal concentrations in the water samples are below the detection limits (BDL). Pb, Cd, Cu and Ni contamination were determined in sediments and in fish tissues (muscle and liver) and it was seen that they were accumulated and biologically magnified in lish tissues. Metal concentration levels in sediment samples were higher than that of water and fish tissues. The highest amount of metal concentrations in sediment samples among seven stations were determined in Usakbuku (Pb: 0.49 ppm), Sakarya River (Cu: 1.12 ppm) and Sariyar (Ni: 0.77 ppm). Unlikely to the other stations, no metal residues were determined in the sediment samples ofAladag Creek Station.     

Trading rules and the environment: Does equal treatment lead to a cleaner world?

In this paper, we consider a three-stage game in the context of a competing exporters model to compare and contrast the effects of discriminatory and uniform (Most Favored Nation, MFN) tariffs on countries’ choice over environmental standards for varying degrees of pollution spillovers. Because of the presence of punishment effects and stronger own and cross-tariff effects, we find that discrimination yields higher standards than MFN (and free trade) independently of the extent of pollution spillovers. When pollution is local and incentives to free ride on other countries’ abatement efforts are weak, we show, however, that welfare is larger under MFN than under discrimination. In a dynamic setting, we consider the impact of symmetric and asymmetric treatments on the sustainability of an international environmental agreement (IEA) and obtain that multilateral cooperation is easier to sustain under discrimination than under MFN (or free trade).     

Seasonal activity of Bombus terrestris L. in east Mediterranean region, Turkey

Bumblebees have economical importance in most of wild and cultivated plants. They can be abundant in suitable habitats and have a broad flower choice. Bombus terrestris was collected at intervals during 2002 and 2003 from various flora and ecosystems of east Mediterranean region of Turkey. In this study, plants visited by Bombus terrestris, seasonal activities, distribution and altitudes were determined. Bombus terrestris have boon seen throughout Turkey in a wide range of habitats from sea level to 1560 m altitude within all the major native vegetation types. Prevalence of queens, workers and males of Bombus terrestris differed due to altitude. More frequently observed at 0-600 m, declining above 600 m in relation to general climate requirements.