Transport,distribution and toxic effects of polychlorinated biphenyls in ecosystems: Review

Investigation of various aspects of the ecological problems of polychlorinated biphenyls (PCBs) has grown and continues to grow with remarkable intensity. However, it appears that certain areas of PCBs research are developed further than the others. For example, chemical and physical behavior and synthesis of PCBs are well studied, while the metabolism of PCBs and other routes of degradation, including toxicological significance and environmental impact, continue to challenge the scientists.In this paper, the chemical and physical properties of PCBs as well as the implications of these properties for the behavior of PCBs in ecological systems are discussed. The effect of PCBs on interrelated ecological systems are described. The distribution and fate of PCBs in the atmosphere, hydrosphere and lithosphere, and transport of PCBs through these systems are discussed. The toxic significance, biological accumulation and ecological magnification are described at various trophic levels.     

Pyrolysis of virgin and waste polypropylene and its mixtures with waste polyethylene and polystyrene

A comparison of waste and virgin polypropylene (PP) plastics under slow pyrolysis conditions is presented. Moreover, mixtures of waste PP with wastes of polyethylene (PE) and polystyrene (PS) were pyrolyzed under the same operating conditions. Not only the impact of waste on degradation products but also impacts of the variations in the mixing ratio were investigated. The thermogravimetric weight loss curves and their derivatives of virgin and waste PP showed differences due to the impurities which are dirt and food residues. The liquid yield distribution concerning the aliphatic, mono-aromatic and poly-aromatic compounds varies as the ratio of PP waste increases in the waste plastic mixtures. In addition to this, the alkene/alkane ratio of gas products shows variations depending on the mixing ratio of wastes.     

Energy and Enviromental Issues in Turkey

The current and future projections of energy utilisation and related environmental impact has been given. Due to the heavy dependance on low grade lignites and imported hard coal, Turkey is going to have problems in the control of CO₂ emissions. Turkey was at first included as an Annex I country according to Kyoto Protocol. Later, it has been removed from the list which is justified considering the previous international environmental impact control applications and relatively much lower energy utilisation in Turkey, compared to Annex I countries. Therefore, Turkey has been removed from the Annex I list.Turkish power generation, industrial and transportation sector will be facing a difficult challenge over the coming 20 yr in complying with environmental impact levels. The developments in the liberalisation of Turkish energy sector since the 1980's is a positive step to overcome the problems.     

Mathematical modeling and computer simulation of radioactive and toxic chemical species dispersion in porous media in the vacinity of uranium recovery operations

The management of uranium recovery operations, such as mill production, tailings, heep leaching or solution mining (in-situ mining), has been one of the most challenging issues facing environmental engineers and scientists in the last decade. Almost any activity (mill production, evaporative and holding ponds, storage sites of chemicals, tailings ponds and transportation) results in radioactive and toxic chemicals contamination of surface and groundwaters. Current estimates based on observations of plant operations indicate that 70–80% of the water used in mill production is lost by seepage and 10–20% by evaporation. This large quantity of seepage raises serious questions as to the degree of migration of radioactive and potentially toxic chemical species from the tailings pond and their impact on the surrounding surface and subsurface environments.This paper discusses the major radioactive and toxic chemicals involved in the uranium recovery operations and presents computer simulation results of their hydrodynamic dispersion, migration and prediction of future material movements.     

Mathematical model and computer simulation of the population dynamics of zooplankton in lake and estuary ecosystems

A mathematical model is developed for the population dynamics and survival probabilities of zooplankton in lake and estuarine. Basic digital computer simulation methodology is used for systematic application of the mathematical model for analysis of the population dynamics of zooplankton. In the analysis of this theoretical modelling, attention is focused on the production and destruction processes of the animal. Both processes are assumed stationary. The birth (production) rate is constant and life-span distribution is independent of time. It is also assumed that the different zooplankton species are independent and share a common aquatic ecosystem, and what happens to one of them does not influence the fate of any other in this system.     

Landscape scale ecological monitoring as part of an EIA of major construction activities: experience at the Turkish section of the BTC crude oil pipeline project

Ecological monitoring is a complementary component of the overall environmental management and monitoring program of any Environmental Impact Assessment (EIA) report. The monitoring method should be developed for each project phase and allow for periodic reporting and assessment of compliance with the environmental conditions and requirements of the EIA. Also, this method should incorporate a variance request program since site-specific conditions can affect construction on a daily basis and require time-critical application of alternative construction scenarios or environmental management methods integrated with alternative mitigation measures. Finally, taking full advantage of the latest information and communication technologies can enhance the quality of, and public involvement in, the environmental management program. In this paper, a landscape-scale ecological monitoring method for major construction projects is described using, as a basis, 20 months of experience on the Baku-Tbilisi-Ceyhan (BTC) Crude Oil Pipeline Project, covering Turkish Sections Lot B and Lot C. This analysis presents suggestions for improving ecological monitoring for major construction activities.     

Impacts of sublethal lead exposure on the hemato-immunological parameters in tilapia (Oreochromis mossambicus)

The effects of exposure of tilapia (Oreochromis mossambicus) to sublethal concentrations of lead on hematological and immunological parameters were investigated. The fish were semistatically exposed to low (L) (0.5 mg L^?1), medium (M) (2.5 mg L^?1), and high (H) (5 mg L^?1) lead concentrations for 14 days. At the end of the trial, red blood cell (RBC) count, hematocrit (Hct) ratio and hemoglobin levels showed significant decreases in M and H groups, while RBC was significantly increased in L group compared to control group. Lysozyme activity showed a decrease in all groups on day 14 compared to control. A decrease in myeloperoxidase activity was seen in M and H groups on day 7, and in all treatment groups on day 14. In conclusion, it was found that exposure of O. mossambicus to lead concentrations affected hematological and immunogical parameters adversely.     

Regeneration of industrial district wastewater using a combination of Fenton process and ion exchange—A case study

Regeneration studies of wastewater effluent from an organized industrial district (OID) for possible reuse in textile industry as process water was investigated. Advanced treatment methods including Fenton process, polyaluminium chloride (PAC) coagulation and ion exchange were applied on OID effluent. In Fenton process removal efficiencies for suspended solids (SS), chemical oxygen demand (COD), SAC₄₃₆ (spectral absorption coefficient), SAC₅₂₅ and SAC₆₂₀ were determined 61%, 36%, 35%, 49% and 67%, respectively. After Fenton process, wastewater samples were coagulated with PAC. Optimum removal efficiencies for SS, COD, Fe ion, SAC₄₃₆, SAC₅₂₅ and SAC₆₂₀ were determined 83%, 18%, 93%, 32%, 36% and 58%, respectively. Ion exchange experiments were conducted on chemically coagulated wastewater samples to improve the quality of wastewater. Optimum dosage of resins was determined. The experiments revealed that 1:1 resin ratio (20 mL H-type resin:20 mL OH-type resin) gave the best removal rates for the parameters considered in this study. Study results indicated that quality of the wastewater was suitable for the process water characteristics of textile industry and unit wastewater treatment cost was determined as 2.54 €/m³.     

Morin protects against acrylamide-induced neurotoxicity in rats: an investigation into different signal pathways

Environmental Science and Pollution Research - The presented study investigates the effects of morin against toxicity induced by acrylamide (ACR) in the brains of Sprague Dawley rats. In this...