Geotechnical evaluation of Ankara clay as a compacted clay liner

This study investigates the geotechnical properties, and mineralogical and permeability characteristics of "Ankara clay" to evaluate its suitability as a compacted clay landfill liner material. The geotechnical index properties of the clayey soil samples collected from the western part of Ankara were determined. All the soil samples were tested for permeability by means of falling head compaction permeameter apparatus. The mineralogy of the soil samples were examined by X-ray diffraction and scanning electron microscope analyses. The cation exchange capacities of the soil samples were determined by the methylene blue adsorption test in order to determine the presence of swelling clay minerals in the soil samples. The influences of the geotechnical indices and mineralogy of Ankara clay on the hydraulic conductivity were investigated. Several landfill profiles containing various compacted clayey lining systems were simulated by the Hydrologic Evaluation of Landfill Performance model. All the soil samples tested led to hydraulic conductivities lower than the suggested regulatory limits (1 x 10(-9) m/s) and therefore, are suitable to be utilized as compacted clay liners in potential sanitary landfill sites. Recommendations regarding field construction of the compacted clay liner are provided

Limestone dimension stone quarry waste properties for concrete in Western Turkey

The aim of this paper is to assess the influence of the composition and texture of the limestone on aggregate properties from the five working dimension stone quarries wastes of Karaburun Peninsula in Western Turkey. The limestone samples were tested to determine their petrographic, mineralogic, and chemical characteristics and aggregate properties. Then, the testing concretes were prepared by using these aggregates, and hardened concrete properties were determined. According to the results obtained, limestone was found to be suitable for use as coarse and fine aggregate in normal-strength concrete production. But, the quality of concretes made using the limestone aggregates were found to be dependent on the silica ratio present in them. The threshold value of the silica ratio is determined to be 2 % by weight for the alkali-silica reaction development in concrete made with the Karaburun dimension stone quarries wastes

Assessment of the Effects of the Pesticide Imidacloprid on the Behaviour of the Aquatic Oligochaete Lumbriculus variegatus

Contaminants, such as pesticides, can cause direct toxic effects when released into aquatic environments. Suitably sensitive species can help us understand and predict the impacts of such pollutants. Automated sediment toxicity testing and biomonitoring has grown rapidly, and biomonitoring instruments have proven appropriate for studying the effects of pollutants. A new approach in online biomonitoring, using the multispecies freshwater biomonitor was developed in the present study, using whole-sediment toxicity tests and behavioural responses of the freshwater oligochaete Lumbriculus variegatus. Endpoints, such as mortality and growth, were used to study the effects of the pesticide imidacloprid and to achieve a gradient of responses; exposures to contaminated sediments were performed over 10 days' duration (short-term tests). High mortality was observed in the three highest concentrations of imidacloprid, and inhibition of behaviour was monitored along a gradient of pesticide concentration. Exposure to imidacloprid-contaminated sediments affected growth, behaviour, and avoidance in L. variegatus