Utilization of sepiolite materials as a bottom liner material in solid waste landfills

Landfill bottom liners are generally constructed with natural clay soils due to their high strength and low hydraulic conductivity characteristics. However, in recent years it is increasingly difficult to find locally available clay soils that satisfy the required engineering properties. Fine grained soils such as sepiolite and zeolite may be used as alternative materials in the constructions of landfill bottom liners. A study was conducted to investigate the feasibility of using natural clay rich in kaolinite, sepiolite, zeolite, and their mixtures as a bottom liner material. Unconfined compression tests, swell tests, hydraulic conductivity tests, batch and column adsorption tests were performed on each type of soil and sepiolite–zeolite mixtures. The results of the current study indicate that sepiolite is the dominant material that affects both the geomechanical and geoenvironmental properties of these alternative liners. An increase in sepiolite content in the sepiolite–zeolite mixtures increased the strength, swelling potential and metal adsorption capacities of the soil mixtures. Moreover, hydraulic conductivity of the mixtures decreased significantly with the addition of sepiolite. The utilization of sepiolite–zeolite materials as a bottom liner material allowed for thinner liners with some reduction in construction costs compared to use of a kaolinite-rich clay.     

Toxic metal (Pb, Cd, As and Hg) and organochlorine residue levels in hake (Merluccius merluccius) from the Marmara Sea, Turkey

Toxic metals (Pb, Cd, As and Hg) and organochlorine residue levels were measured in hake (Merluccius merluccius) from the Marmara Sea. Biota samples were collected by a trawling cruise of the R/V ARAR in August and December 2009. The concentrations of toxic metals varied between Pb, 3.23-14.4; Cd, <0.01-2.14; Hg, 0.01-0.18 and As, 0.01-0.21 [Formula: see text]g g(-1) dry wt. Pb levels in the Marmara Sea were found to be higher than the critical limits set by the both Turkish Ministry of Environment for Aquatic Products (1 μg g(-1) wet wt.) and European countries (2.0 μg g(-1), UNEP 1985). In contrast, As and Hg levels were found to be lower than the critical limits for two periods. Cd contents of fish from the Marmara Sea were also comparable to or slightly lower than contents of fish from the Southern Black Sea Shelf. The results of organochlorine residues ranged between total HCH, <0.05 and 99 ng g(-1); endrin, <0.001 and 381 ng g(-1); alpha-endosulphan, <0.05 and 90 ng g(-1); beta-endosulphan, <0.05 and 15.3 ng g(-1); o,p DDE, 3.5 and 52.4 ng g(-1); p,p DDE, 7.4 and 139 ng g(-1); o,p DDD, 1.5 and 90.2 ng g(-1) and p,p DDD, 2.7 and 86 ng g(-1) wet weight. The rivers for the distribution of organochlorine levels in the Marmara Sea ordered from highest to lowest as Dil R. > Susurluk R. > Biga R. > G?nen R. The high levels of o,p and p,p DDE, and o,p and p,p DDD compounds, which are metabolites of DDT, indicate its illegal use. Toxic metal and organochlorine residue levels of fish are significantly higher than levels from the Mediterranean Sea.     

A new distribution of Caucasian wingnut (Pterocarya fraxinifolia (Poiret) Spach) in the Kahramanmaras region, Turkey

Caucasian wingnut (Pterocarya fraxinifolia (Poiret) Spach) is a relict tree species having limited natural distribution in Turkey. In this study, a new distribution of this species in the Kahramanmaras region was explained. This distribution occurs in Onsenhopuru and Yavuzlar villages and Yesilyore town of Turkoglu district, at elevations between 600 and 640 m along Orcan stream, and continues about 4 km. In this area, Caucasian wingnut had about 100 trees. This distribution area of the species, quite important for biodiversity, should be protected and the existing individuals should be evaluated as a gene resource. Especially vegetative reproduction of the species should be started and the seedlings obtained should be used at the margins of lakes and streams, parks and large gardens, avenues, boulevards, and streets in the region.     

Investigation of acute toxicity of fenitrothion on peppered corydoras (Corydoras paleatus) (Jenyns, 1842)

Fenitrothion, as an organophosphothionate insecticide, is a contact insecticide and selective acaricide, also used as a vector control agent for malaria in public health programs. A 96 h LC50 value of fenitrothion, a potential toxic pollutant contaminating aquatic ecosystems, was determined on the adult peppered corydoras (Corydoras paleatus). The experiments were repeated three times. The static test method of acute toxicity test was used. Water temperature was regulated at 23 +/- 1 degrees C. In addition, behavioral changes at each fenitrothion concentration were observed for the individual fish. Data obtained from acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The 96 h LC50 value for peppered corydoras was estimated as 3.51 mg/l.     

Monitoring and assessment of land use status by GIS

The objectives of this study were to assess land suitability andto monitor the spatial and temporal changes in land use types (LUTs)by using GIS. The study was conducted in an irrigated area of 920ha, located in the East Mediterranean region of Turkey. Archiveddata of LUTs were utilized. Data analysis was conducted by usingArcInfo and ArcView GIS softwares. The land characteristics werecompared with land requirements of present LUTs by taking intoaccount the land evaluation results. Three major soil series andtwelve different LUTs were identified. Corn and citrus were themost planted LUTs in the assessment period. Generated mapsdemonstrated how LUTs changed spatially and temporally. Most LUTswere clustered in certain areas indicating that farmer'sselection of LUTs was affected by their habits and neighbor'sbehavior. Land suitability assessment results indicated thatCanakci and Mursel soil series were found to be highly suitable forall LUTs while Arikli soil series was determined to be moderately suitablecitrus, vegetables and watermelon. Citrus plantationmaps overlaid on soil series maps demonstrated that the citrushas not been planted completely on suitable areas. Landsuitability assessment showed that citrus plantation in Arikliseries would result in 40% yield loss and 58% of land is notused at its potential.     

Effects of gradually increasing drying temperatures on energy aspects,fatty acids,chemical composition,and in vitro ruminal fermentation of acorn

Environmental Science and Pollution Research - Acorns are commonly used to meet energy, protein, and mineral needs of livestock in various parts of the world. However, since acorns have quite a...     

Advanced physico-chemical treatment experiences on young municipal landfill leachates

In this study, Membrane Filtration (UF+RO), Struvite (MAP) precipitation and ammonia stripping alternatives were studied on biologically pre-treated Landfill Leachate. The results indicated that the system including the Upflow Anaerobic Sludge Blanket Reactor (UASBR) and Membrane Reactors (UF+RO) has been offered as an appropriate treatment alternative for young landfill leachates. This system provided high removals of COD, colour and conductivity (>98-99%). For ammonia removal, struvite precipitation was applied at the stoichiometric ratio (Mg:NH4:PO4=1:1:1) to anaerobically pre-treated raw landfill leachate effluent having an influent ammonium concentration of 2240 mg/l. Maximum ammonium nitrogen removal was observed as 85% at pH of 9.2. In ammonia stripping following 2 h of aeration, the removal was 72% at pH=12 while the removals were around 20% at pH=10 and pH=11. When membrane reactor, and struvite precipitation or ammonia stripping was applied to anaerobically pre-treated effluents, the results indicated that each system could be used as an appropriate post-treatment option for young landfill leachates. In economic aspect, ammonia stripping was found as the cheapest alternative with high ammonium removal. However, when both high COD and ammonium removals were to be achieved membrane technology such as UF+RO (SW) could be considered as the most appropriate system due to the fact that COD removal could be obtained very low by ammonia stripping.     

Effective antibacterial and antioxidant properties of methanolic extract of Laurus nobilis seed oil

This study was carried out to determine the in vitro antimicrobial and antioxidant activities of the essential oil, seed oil, and methanolic extract of seed oil obtained from Laurus nobilis L. (Lauraceae). The methanolic extract of seed oil exhibited more effective antibacterial activity comparing to essential oil and seed oil, GC-MS analyses of the essential oil resulted in the identification of 25 compounds. 1.8-Cineol (44.72%), a-Terpinyl acetate (12.95%), Sabinene (12.82%) were the main components. The fatty acid composition was characterized with the high content of linoleic acid (40.79%) and lauric acid (38.08%). The 50% (IC50) inhibition activity of the essential oil on the free radical DPPH was determined as 94.655 mg ml(-1), whereas IC50 value of methanolic extract of seed oil was found unstable. In the case of the linoleic acid system, oxidation of linoleic acid was inhibited by essential oil and methanolic extract of seed oil, which showed 64.28 and 88.76% inhibition, respectively. The inhibition value of the methanolic extract of seed oil was quite close to the synthetic antioxidant BHT, 92.46% inhibition.     

An investigation of halogens in Izmit hazardous and clinical waste incinerator

In the combustion facilities, halogens (Cl, F, Br, I) should be considered with regard to the control of the compounds such as polychlorinated dibenzodioxins (PCDD), polychlorinated dibenzofurans (PCDF), halogenated polyaromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and volatile heavy metals formed as a result of incomplete combustion and caused adverse environmental effects. In this study halogens were observed in Izmit Hazardous and Clinical Waste Incinerator (IZAYDAS). Halogen contents of the combustion menu, flue gas, fly ash, bottom ash and filter cake were measured and their distributions in these exit streams were determined. Results showed that the major part of the halogens was partitioned to solid residues, i.e., bottom ash and filter cake which represents the removal by wet scrubbers. Fly ash and flue gas fractions of halogens were much lower due to the reduced formation of volatile compounds.