Levels of organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers in fish species from Kahramanmaras, Turkey

The levels of organohalogenated contaminants, such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in four fish species (Acanthobrama marmid (kalashpa), Cyprinus carpio (carp), Chondrostoma regium (nose-carp), and Silurus glanis (wels)) from the Sir Dam Lake, Kahramanmaras, Turkey. These species were selected for their characteristic feeding behaviour and their importance to local human fish consumption. DDTs were the predominant organohalogenated contaminants in all species, with the p,p'-DDE contributing to more than 90% to the total DDTs. Other OCPs, such as hexachlorocyclohexane (HCH) isomers, chlordanes and hexachlorobenzene (HCB) were found at much lower levels in all five species. The levels of PCBs and PBDEs (on wet weight basis) were lower than in similar species from European or American freshwater systems. PBDE data were measured for the first time in fish species from Turkish environment. Lipid-based concentrations of OCPs, PCBs and PBDEs were higher in wels than in the other species and this was related to its piscivorous feeding mode and to its higher lipid content. Contrarily, concentrations of pollutants in nose-carp were the lowest, in agreement with its more herbivorous diet. A preferential accumulation in muscle compared to liver was observed for all OCPs, PCBs, and PBDEs in wels and carp, while in nose-carp, a preferential accumulation in liver was observed only for PBDEs, p,p'-DDT and PCBs. Racemic amounts for alpha-HCH were measured in all investigated muscle and liver samples, except for carp muscle.     

Removal of MCPA from aqueous solutions by acid-activated spent bleaching earth

The removal of MCPA (4-chloro-2-methyl phenoxyacetic acid) from aqueous solutions by activated spent bleaching earth (SBE) was studied as a function of time, initial concentration, adsorbent concentration, and temperature. The Langmuir and Freundlich isotherms were fitted by the adsorption data obtained. The values of Langmuir and Freundlich constants were determined. The adsorption kinetics was described by the Lagergren equation. Mass transfer coefficient and thermodynamic parameters were also calculated. Column experiments were conducted and brekthrough capacities were found for different concentrations and different flow rates. The study demonstrates that acid-treated SBE could be used as an efficient adsorbent for the removal of MCPA-bearing wastewater effluents.     

Evaluation of growth potential of Crimean juniper (Juniperus excelsa Bieb.) seedlings for the first growing season under Tekir forest nursery conditions in Kahramanmaras,Turkey

In this study, growth potential of Crimean juniper (Juniperus excelsa Bieb.) seedlings for the first growing season under Tekir Forest Nursery conditions in Kahramanmaras was evaluated. The height growth of Crimean juniper seedlings was relatively close to that of Lebanon cedar (Cedrus libani A. Rich.) seedlings produced in the same nursery, but their root collar diameters were fairly lower than that of Lebanon cedar seedlings. According to coniferous seedling standards of Turkish Standards Institute, the height growth of Crimean juniper seedlings was fairly good, but their root collar diameters were slightly small. In this respect, that 2+0 or 1+1 Crimean juniper seedlings are used in reforestation activities in the region would be more useful than 1+0 seedlings.     

Field evaluation of a tailor-made new passive sampler for the determination of NO2 levels in ambient air

This study describes the field evaluation of a tailor-made new glass passive sampler developed for the determination of NO(2), based on the collection on triethanolemine (TEA)-coated fibre filter paper. The sampler has been derived from a Palmes design. The overall uncertainty of the sampler was determined by using Griess-Saltzman ASTM D 1607 standard test method as a reference method. The agreement between the results of the passive sampler and the reference method was +/-7.90% with the correlation coefficient of 0.90. Method precision in terms of coefficient of variance (CV) for three simultaneously applied passive samplers was 8.80%. The uptake rate of NO(2) was found to be 2.49 ml/min in a very good agreement with the value calculated from theory (2.63 ml/min). Sampler detection limit was 1.99 microg/m(3) for an exposure period of 1 week and the sampler can be stored safely for a period of up to 6 weeks before exposure. A comparison of the sampler performance was conducted against a commercially available diffusion tube (Gradko diffusion tube). The results from the applied statistical paired t test indicated that there was no significant difference between the performances of two passive samplers (R (2) > 0.90). Also, another statistical comparison was carried out between the dark and transparent glass passive samplers. The results from the dark-colour sampler were higher than that from the transparent sampler (approximately 25%) during the summer season because of the possible photodegradation of NO(2)-TEA complex.     

Successes and failures of compulsory risk mitigation: re‐evaluating the Turkish Catastrophe Insurance Pool

The Turkish Catastrophe Insurance Pool (TCIP) is one of the best practices of public–private partnerships in an emerging market designed to reduce economic losses from disasters. This paper reviews the application of this compulsory mechanism along with data relating to the performance of the scheme following recent earthquakes in Turkey. We also consider the current perceptions of Turkish society towards the TCIP and how they can be enhanced. Our conclusions aim to assist stakeholders in government, homeowners, insurance companies, media, banks and civil society to appreciate the value of the system and key actions necessary to improve it.     

Preparation of briquettes from the Golden Horn bottom sediments by hydro-thermal agglomeration process.

The Golden Horn (GH) sediments, which consist mainly of clay, organic substances and heavy metals, are formed with the contribution of industrial and domestic wastes released in the Golden Horn Estuary. On account of their mineralogical and chemical composition, these sediments may be regarded as a suitable raw material for briquette production. In this study, the utilization of GH dredged bottom sediments was investigated for preparation of briquettes. Dried GH sediments were mixed with lime and sand in different percentages, moulded at various squeezing pressures and hardened under several steam pressure values by autoclaving. The briquettes produced through these different process conditions were tested for compressive strength according to the Turkish standards (TS705). It was found that variations in compressive strength were dependent on the amount of lime (Ca(OH)2) and sand (SiO2) added. Results show that the compressive strength increased with increasing lime and decreasing sand in the mixtures prepared for briquettes. It is concluded that briquettes with a compressive strength value of 294 kgf cm(-2) can be produced. This allows the GH sediments to be taken into account as a raw material in brick production, as far as compressive strength requirements are concerned. This possibility may represent an important way either for reducing environmental pollution or for recycling waste materials in industrial applications.     

Evaluation of the inhibitory effect of abamectin on mammalian butyrylcholinesterase: Enzyme kinetic and molecular docking studies

ABSTRACT

Abamectin, a blend of the natural avermectins B_1a and B_1b, is a widely-used insecticide/miticide with relatively low toxicity to mammals. Exposure to high doses of it, however, leads to cholinergic-like neurotoxic effects. Butyrylcholinesterase, which is best known for its abundant presence in plasma, is a serine hydrolase loosely coupled with the cholinergic system. It protects and supports the neurotransmitter function of its sister enzyme acetylcholinesterase. Here, using experimental and computational studies, we provide evidence demonstrating that abamectin is a potent (IC₅₀ = 10.6 μM; K_i = 2.26 ± 0.35 μM) inhibitor of horse serum butyrylcholinesterase and that it interacts with the enzyme in a reversible, competitive manner predictively to block the mouth of the active-site gorge of the enzyme and to bind to several critical residues that normally bind/hydrolyze choline esters.