14C-carbaryl residues in hazelnut

A hazelnut ocak (shrub growing form) in the field in Black Sea region of Turkey was treated with commercial carbaryl insecticide spiked with 14C-carbaryl. Three months later, the harvested hazelnuts were separated into husk, shell, and kernel components, then homogenized and analyzed. The total and unextractable (bound) 14C-residues were determined by combustion and the extractable 14C-residues were obtained by extracting the samples with methanol. Concentrated extracts were first analyzed by thin layer chromatography (TLC). The extracts were also subjected to a series of liquid-liquid extraction procedures for clean-up and the final extracts were analyzed by high performance liquid chromatography (HPLC). Crude hazelnut oil was also extracted with hexane and analyzed for total 14C-residue. A total of 1.3% of applied radioactivity was recovered from the total nut harvested, with 0.04%, 0.06%, and 1.2% present in shell, kernel, and husk, respectively. The results show that the inedible husk and shell contained 95.7% 14C, whereas the edible kernel contained 4.3% of the total 14C recovered. The terminal 14C-residue in hazelnut kernel and oil did not contain carbaryl and/or its metabolite naphthol.     

Cadmium exposure from the cement dust emissions: a field study in a rural residence

The cement dust is one of the causes of pollution in the environment. In the present study, the cadmium concentrations of soil and plant specimens taken from a rural area exposed to cement factory emissions were determined and also the blood concentrations and sensitivity conditions in humans residing in this rural area were investigated. The 108 soil (36 for control) and plant specimens were collected from eight different directions of the cement plant located in Cukurhisar town in Eski?ehir city. Blood samples of the individuals residing in this area were taken from 258 subjects (258 for control) following a physical examination, and patch tests were also applied. The results show that the cadmium concentrations of the soil and plant specimens taken from different places in different directions of the factory were higher than in the control areas. The physical examination of subjects did not reveal results different from those of the control group except for the diagnosis of contact dermatitis. The analysis of venous blood samples showed that cadmium concentrations were found to be within the reference values given for both groups, but higher in the subjects (p<0.001). According to the results of patch tests, sensitivity to cadmium was found to be more frequent for the subject group than the control group (p<0.05). Those results show that, although clinical tools revealed no toxic effects for the subject, except contact dermatitis, the cement plant increases cadmium pollution on the surrounding environment.     

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.     

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。