Effect of humic deposit (leonardite) on degradation of semi-volatile and heavy hydrocarbons and soil quality in crude-oil-contaminated soil

In order to investigate the bioremedial potential of humic deposit (leonardite), the effects of the treatments of leonardite and a commercial bioaugmentation agent on the degradation of a variety of petroleum hydrocarbons (C13–C31) and soil enzyme activities (urease acid-alkaline phosphatase and dehydrogenase) were tested within a soil incubation experiment lasting 120 days. Experimentally crude-oil-contaminated soil (2.5%) was regulated to a C:N:P ratio (100:15:1; Oilcon), amended with 5% of leonardite and regulated to the same C:N:P ratio (Oilcon-L) or mixed with a commercial bioaugmentation product (Oilcon-B), respectively. In the short period of incubation (60 days), Oilcon and Oilcon-B treatments showed higher hydrocarbon degradations, whereas Oilcon-L showed higher hydrocarbon degradation over Oilcon and Oilcon-B treatments in the long-term (120 days). Applying contaminated soil with leonardite increased urease (LSD, 4.978, *P?<?0.05) and dehydrogenase (LSD, 0.660, *P?<?0.05) activities. However, acid and alkaline phosphatase activities showed no certain inclination between different treatments. Dehydrogenase seemed to be more related to hydrocarbon degradation process. Overall results showed that leonardite enhanced biodegradation of petroleum hydrocarbons and also stimulated soil ecological quality measured as soil enzyme activities.     

Concentrations of cadmium and lead heavy metals in Dardanelles seawater

Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary experiments the optimal analytical condition for oxine concentration was found to be 2.10⁻⁵ M, at pH 7.7, the accumulation potential was −1.1 V, and the initial scannig potential was −0.8 V. The peak potentials were found −0.652 V for Cd and −0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification (LOQ) were found to be by voltammetry as 0.588 and 1.959 μg l⁻¹ (RSD, 5.50%) for Cd and 0.931 and 3.104 μg l⁻¹ (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained.     

The preference of the most appropriate radical-based regeneration process for spent activated carbon by the PROMETHEE approach

Environmental Science and Pollution Research - In this study, regeneration of spent granular activated carbon (GAC) with reactive dye by hydroxyl and sulfate radical-based advanced oxidation...     

The formation of wood jams in Kamchatka rivers and their role in juvenile fish distribution

In piedmont rivers of the Kamchatka Peninsula, wood jams play a major role in channel formation and largely determine the density distribution of juvenile fish along the river, offering them convenient habitats in areas with rapid current. It has been found that juvenile fish density in wood jams is 1.5–3 times higher than in adjoining open shoals. An analysis of data on the location and morphology of more than 200 wood jams has shown that their occurrence frequency and size depend mainly on river size (flow discharge), the type and morphology of river channel, and the type of tree stand in the floodplain.     

Monitoring metal contamination levels and fecal pollution in clam (Tapes decussatus) collected from Izmir Bay (Turkey)

The aim of this study was to monitor the heavy metal contents and fecal pollution in Tapes decussatus (carpet shell clam) from Izmir Bay (Eastern Aegean). Bivalve mollusks were sampled on January, March, July, and October 2007 in the Izmir Bay. Izmir Bay is one of the great natural bays of the Mediterranean. Concentrations of heavy metals were determined in the clams from the different seasons. Fecal coliform densities were determined to evaluate the degree of water pollution and clams’ microbiological accumulation of the classical microbial pollution indicators. The concentration of heavy metals in T. decussatus from Izmir Bay were Hg 0.044–0.13; Cd 0.026–0.24; Pb 0.38–1.2; Cr 2.3–3.7; Cu 6.4–8.4; Zn 56.0–81.8, and Ni 8.1–9.6 μg/g (dry weight). The maximum values were generally obtained in July and March except Ni. This study found that the levels of heavy metals except Cr in T. decussatus were below Spanish and European Communities legislations for shellfish as food. Microbial pollution indicators (heterotrophic bacteria and fecal coliform) were measured in T. decussatus. Maximum heterotrophic bacteria and fecal coliforms were recorded in the winter while the lowest were detected in summer.     

Assessment of trace metal pollution in surface sediments of Nemrut Bay, Aegean Sea

Surface sediments collected from nine stations in Nemrut Bay, Aegean Sea were analyzed for trace metals (Hg, Cd, Pb, Cr, Cu, Zn, Mn, Ni, Fe, As, and Mg) and grain sizes. The results were compared with the numerical sediment guidelines used in North America as well as literature values reported for similar studies conducted in Izmit Bay and Izmir Bay. The metal levels were also evaluated according to the enrichment factor and contamination factor analyses. The analyses revealed significant anthropogenic pollution of Hg, Pb, Zn, and As in the surficial sediments of Nemrut Bay.     

Perspectives for pilot scale study of RDF in Istanbul,Turkey

Municipal solid waste (MSW) is one of the most important environmental problems arising from rapid urbanization and industrialization. The use of alternative fuels in rotary kilns of cement plants is very important for reducing cost, saving fossil fuels and also eliminating waste materials, accumulated during production or after using these materials. Cement industries has an important potential for supplying preferable solutions to the waste management. Energy recovery from waste is also important for the reduction of CO₂ emissions.This paper presents an investigation of the development of refuse derived fuel (RDF) materials from non-recycling wastes and the determination of its potential use as an alternative fuel in cement production in Istanbul, Turkey. RDF produced from MSW was analyzed and its effects on cement production process were examined. For this purpose, the produced RDF was mixed with the main fuel (LPG) in ratios of 0%, 5%, 10%, 15% and 20%. Then chemical and mineralogical analyses of the produced clinker were carried out. It is believed that successful results of this study will be a good example for municipalities and cement industries in order to achieve both economic and environmental benefits.     

Preliminary investigation of sensitive biomarkers of trace metal pollution in mussel (Mytilus galloprovincialis) from Izmir Bay (Turkey)

The aim of this study was to identify possible relationships between biochemical- superoxide dismutase (SOD), glutathione peroxidase (GPx), thiobarbituric acid reactive substances (TBARS) of mussels (Mytilus galloprovincialis) and chemical (Hg, Cd, Pb, Cr, Cu, Zn, Mn and Fe) contaminants from relatively clean area (Middle Bay) and heavily polluted area (Inner Bay) of the Izmir Bay. Sampling of mussels was performed in the beginning of May 2004. Mussel digestive glands have been used for biochemical assays. Trace metal content was determined by atomic absorption spectrophotometer using standard procedures. Metal contents in mussels collected at polluted site increased compared to the middle part of the bay. While there was a positive correlation between metals and SOD enzyme activity, there was a negative correlation between metals and GPx enzyme activity. An increase was observed in SOD enzyme activity and a decrease of GPx enzyme activity at the inner part of the bay.     

Modeling wastewater discharge at the planning stage of a marine outfall system

The possibility of marine discharge of a negatively buoyant industrial waste was evaluated by a modeling study using Killworth 3-D, which is the first version of the Modular Ocean Model (MOM). The Model was run with the recorded wind direction and speed on the cruise dates and the circulation patterns for surface and subsurface were found to be similar with the current meter measurements. Model scenarios have been set-up in order to estimate the intensity and direction of the currents in the Nemrut Bay under the condition of wind blowing from a definite direction for a long time. MOM model has been run for four major wind directions, each having duration of 10 days and the behavior of the discharge plume in the worst case has been traced. Also, the behavior of the discharge plume in the real case has been estimated by using the wind data of the region. According to the model results, impact of trace elements that compose the discharge effluent is limited both in time and space. It is concluded that trace elements will leave the Bay in a short time due to the short residence times.     

Spatial Distribution Patterns,Sources of Heavy Metals,and Relation to Ecological Risk of Surface Sediments of the Cyprus Northern Shelf (Eastern Mediterranean)

In this study, the spatial distribution of metals and the sources of metal pollution were investigated along the Northern Shelf of Cyprus (Mediterranean Sea). The concentrations of heavy metals and organic matter were measured in sediments collected from the Gemi Konagi, Girne, and Gazi Magusa areas. Measured metal values were compared with Mediterranean background concentrations. Cu and Zn concentrations at the Gemi Konagi area and all of the Cr values were higher than Mediterranean backgrounds. The metal levels were evaluated by the enrichment factor (EF), contamination factor (C_f) and degree of contamination (C_d). EF results indicated that heavy metal sources were probably originated from natural processes and mining activities. The C_f values of Hg indicated low contamination. The C_d (degree of contamination) values for all heavy metals also showed a low degree of contamination at the study area. Metal levels were also compared with the numerical Sediment Quality Guidelines (SQG) for an environmental risk assessment. Results showed that sediments were classified as heavily polluted by Cu and moderately polluted by Zn at Gemi Konagi and heavily polluted by Cr and Ni contamination at all sampling areas per the SQG.