Leyla Tolun - Academia.edu (original) (raw)

Papers by Leyla Tolun

Environment International, Aug 1, 2006

Izmit Bay and its coastal environment was strongly affected by the August 17th, 1999 Izmit Earthq... more Izmit Bay and its coastal environment was strongly affected by the August 17th, 1999 Izmit Earthquake. The changes in the Bay ecosystem and its chemical oceanography have been studied in detail previously [Okay, O.S., Tolun, L, Telli-Karakoç, F., Tüfekçi, V., Tüfekçi, H. And Morkoç, E. 2001. Ýzmit Bay ecosystem after Marmara earthquake and subsequent fire: The long-term data. Marine Pollution Bulletin 42, 361–369; Balkýs, N. 2003. The effect of Marmara (Izmit ) Earthquake on the chemical oceanography of Izmit Bay, Turkey. Marine Pollution Bulletin 46, 865–878.]. In this study surface sediments collected from the Izmit Bay before and after the earthquake have been analysed for total and individual (14 compounds) polycyclic aromatic hydrocarbons (PAH). Analyses have been performed by high performance liquid chromatography with fluorescence detection (HPLC/FD). Before the earthquake, total PAH concentrations in the Bay sediments ranged from 120 to 8900 ng/g while after the earthquake PAH concentrations varied between 240 and 11,400 ng/g. Molecular indices based on isomeric PAH ratios used to differentiate the pollution sources, clearly indicate the differences in molecular distribution of PAHs before and after the earthquake. Sediment data obtained before the earthquake shows that most of the contamination originated from high temperature pyrolytic inputs while after the earthquake it originated from petrogenic sources. This difference emphasises the environmental impact of uncontrolled discharges from petroleum industries after the earthquake. The LMW/HMW ratio (sum of the low molecular weight PAHs / the sum of higher molecular weight PAHs) predominance also changed after the earthquake as a result of the strong water movements. According to the characteristics of aromatic rings distributed in the bay sediments, the soluble parts of the total PAH were probably transferred to the water column after the earthquake as a result of resuspension process. The TEL/PEL (Threshold Effect Level / Probable Effect Level) analysis suggests that the Izmit Bay sediments were likely contaminated by acutely toxic PAH compounds.

Environmental Pollution, Oct 1, 2002

In 1999, the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), the total PAH and poly... more In 1999, the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), the total PAH and polychlorinated biphenyls (PCBs) were measured in sea water, sediment and mussels collected along the coast of Izmit Bay, the most important bay of the Marmara Sea. The total-PAH concentrations, measured by Spectrofluorometry were in the range of 1.16-13.68 microg/l in sea water, in the range of 30.0 1670.0 microg/g dry weight in sediments and in the range from 5.67 to 14.81 microg/g wet weight in edible part of mussel. HPLC revealed Phenanthrene (three rings), chrysene (four rings) and benz[a]antracene (five rings) to be the dominant PAHs in sea water, while 16 different PAHs compounds were observed and measured in mussel samples. The most pollution occured at Dogu Kanali and Dil Deresi where were the main rivers containing wastes fall into the the Izmit Bay. Although the maximum mono-ortho PCB concentrations in sea water were measured in the Dil Deresi River (26.33 ng/l) and the Solventaş (22.19 ng/l) stations, maximum PCB concentrations in mussels were measured in the SEKA (28.11 microg/kg) and the Dil Deresi River (25.68 microg/kg). The dominant congeners of PCBs were from tetra to hexachlorobiphenyls. The toxicity equivalent values were very low in sea water and mussels.

Environment International, 2001

Izmit Bay is one of the most polluted and populated enclosed sea in Turkey. It has been the centr... more Izmit Bay is one of the most polluted and populated enclosed sea in Turkey. It has been the centre of industrial activities for the last 30 years. Seven major sources enter the bay waters along the north coastline of the bay. This investigation forms part of continuing ecotoxicology studies in the Izmit Bay designed to constrain and minimise the pollution caused by flourishing industry and a growing population. Sediments sampled from the mouths of the major discharges of Izmit Bay were analysed for their organic carbon, total polycyclic aromatic hydrocarbon (t-PAH) and trace inorganic element (Cd, Al, As, Pb, Hg and Cu) contents and compared with those found in the sediments from the reference station in the outer bay (in the Marmara Sea). The toxicity of sediments was determined in the bulk and elutriate samples by using algal (Phaeodactylum tricornutum) batch bioassays. Chemical data showed that the sediments collected from the inner sites of the bay have been contaminated with Cd, Hg, As and PAHs. Organic carbon contents were also found higher. All the major industrial discharges into the bay are now biologically treated but bioassays performed with bulk sediments revealed that the recent sediments are toxic to the microalgae throughout the bay. The results are consistent with the previous toxicity studies performed with the industrial discharges.

Springer eBooks, Dec 13, 2007

On 17 August 1999 a powerful earthquake struck the eastern part of Marmara Region and Izmit Bay, ... more On 17 August 1999 a powerful earthquake struck the eastern part of Marmara Region and Izmit Bay, the most industrialized and populated area of the region. Environmental effects of the earthquake and subsequent refinery fire were partly investigated by several scientists (

Environment International, May 1, 2006

The toxicity of the polyaromatic hydrocarbon pyrene to Mytilus edulis and Mytilus galloprovincial... more The toxicity of the polyaromatic hydrocarbon pyrene to Mytilus edulis and Mytilus galloprovincialis was investigated in experiments conducted in the United Kingdom for M. edulis and in Turkey for M. galloprovincialis. Experimental conditions of temperature and salinity were chosen to be appropriate to the ambient conditions in which the mussels typically live. The effect of different feeding regimes on pyrene bioaccumulation and toxicity was also investigated. Feeding rate and neutral red retention biomarker techniques were used for toxicity assessment. An experiment with M. edulis demonstrated that mussels exposed to pyrene accumulated increasing amounts of this compound throughout a 15-day exposure period and that accumulation increased in relation to exposure concentration and with increasing concentration of unicellular algal food material. However, in these experiments, which were protected from UV light, there was no clear relationship between pyrene concentration in tissues and feeding rate. A clear concentration-response relationship was observed between tissue concentration and neutral red retention for days 1 and 7 of the experiment, but this relationship was lost by day 15, with evidence of the cells recovering. A similar experiment was conducted with M. galloprovincialis at a single (high) pyrene concentration in darkness. The feeding rate of the exposed mussels was always lower than the feeding rate of the control mussels, although the difference was insignificant at 7-day exposure. A decreasing trend in health status of the mussels was indicated by the neutral red retention assay results after 7 and 15 days of exposure to pyrene. In a third experiment (with M. galloprovincialis), an illuminated algal chemostat system containing pyrene was inserted in the exposure system as the food source for the mussels. Both biomarker results showed conclusively that toxic effects correlated with pyrene bioaccumulation, though there was no clear evidence for light-enhanced toxicity. These experiments showed that experimental conditions such as salinity, temperature and feeding regime and perhaps the species of mussel used may influence whether pyrene is perceived as being a toxic molecule.

Journal Of Environmental Science And Health, Part A, Jul 4, 2019

This study aims to assess the impact of the sediment in the potential dredging areas of the Marma... more This study aims to assess the impact of the sediment in the potential dredging areas of the Marmara Sea. To that aim, sediments were analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and heavy metals, sources were discussed, and toxicity tests were applied. For assessment, lower and upper limits of Turkish draft regulation (L TR , U TR) and UNEP-MAP's guidance document (LCT, UCT), and effects range low and median (ERL, ERM) were used. Total concentrations were found between 562 and 8643 mg kg À1 for PAHs, 4-36 mg kg À1 for PCBs, and 14-190 mg kg À1 for OCPs. The highest P PAH concentrations were measured in Golden Horn, and none of the PAH compounds was above ERM. ERL and UCT were exceeded in _ Istinye and Golden Horn stations. The highest P PCBs and P OCPs levels were determined in _ Izmit Bay (IB). RPCBs in IB were higher than ERL and L TR , while RDDT were found above ERM and UCT. High concentrations of chromium ($190 mg kg À1) and copper ($180 mg kg À1) in Golden Horn and mercury in IB ($4 mg kg À1) were detected. The highest toxicities were observed in _ Istinye and _ Izmit Bay. According to the regulations, none of the sediments can be dumped.

Cercetări Marine - Recherches Marines, 2021

This publication has been produced with the financial assistance of the European Union. The conte... more This publication has been produced with the financial assistance of the European Union. The contents of this publication are the sole responsibility of NIMRD and can in no way be taken to reflect the views of the European Union.

Iranian Journal of Fisheries Sciences, 2014

The present study was conducted to examine the impact of cage aquaculture on benthic communities ... more The present study was conducted to examine the impact of cage aquaculture on benthic communities in coastal areas (depth 25 to 50 m) from fish farming operations located along the southeastern Black Sea (Ordu-Persembe, Trabzon-Yomra and Rize central). Sampling was conducted seasonally from April 2007 to 2009. Sediment samples were taken using Ekman Grab (box core- 0.04 m 2 ). Temperature, salinity, and water velocity were periodically measured to determine influencing sedimentary organic matter in the sediment, oxygenation, and anoxic conditions. In addition, grain size of sediment, organic carbon content, and distribution of benthic communities were investigated. In order to determine benthic impact of fish farms on the region, Shannon – Wiener diversity index (H’), AMBI (AZTI Marine Biotic Index) and M-AMBI (Multivariate- Marine Biotic Index) indices were used. Results of current study showed that benthic zone ecological quality of stations with number 01, 02, 03, and 04 at Ordu-P...

The MISIS Joint Cruise, the main activity of the WP2 of the project MISIS (MSFD GUIDING IMPROVEME... more The MISIS Joint Cruise, the main activity of the WP2 of the project MISIS (MSFD GUIDING IMPROVEMENTS IN THE BLACK SEA INTEGRATED MONITORING SYSTEM), has aimed, among others, to collect additional data and produce homogeneous datasets based on a common sampling procedure and laboratory analysis of specific contaminants, as well as to provide useful information regarding the assessment of laboratories’ performances in the Western Black Sea region. In addition, the expected results of the cruise could contribute to the improvement and revision of national monitoring strategies in the region, as well as to bring new knowledge in order to prepare the Articles 11 and 13 of MSFD by the EU countries in the region. The cruise was carried out onboard R/V Akademik in the Western Black Sea, during 22-31 July 2013. The selected transects, Constanta, in the Romanian waters, Galata, in the Bulgarian waters, and Igneada, in the Turkish waters, were considered representative for the purposes of the ...

Sakarya University Journal of Science, 2018

Bu çalışma, dip tarama faaliyetleri neticesinde ortaya çıkan dip tarama malzemelerinin (DTM) beto... more Bu çalışma, dip tarama faaliyetleri neticesinde ortaya çıkan dip tarama malzemelerinin (DTM) beton uygulamalarında ince agrega olarak faydalı kullanımı için bir yıkama-eleme tesisi tasarlanmasını, bu tesise ait ilk yatırım ve işletme maliyetlerinin ortaya konulmasını ve laboratuvar ölçekli DTM yıkama-eleme denemeleri sonucunda ortaya çıkan atıksuyun karakterizasyonunun ve yönetiminin belirlenmesini kapsamaktadır. Bu çalışma ile DTM’nin yıkama-eleme ön işlemine tabi tutulması durumunda yüksek klorür, sülfat ve su içeriğinin giderilerek ince agrega olarak beton çalışmalarında kullanılabileceği, oluşan yıkama-eleme atıksuyunun kanalizasyona/denize deşarjına risk oluşturacak herhangi bir kirletici içermediği tespit edilmiş olup olası 1.500 m3/gün kapasiteli DTM yıkama-eleme tesisinin ilk yatırım ve işletme maliyetlerinin sırasıyla 6.753.600 TL ve 2.366.810 TL ve birim maliyeti ise 6,3 TL/ton olarak hesaplanmıştır.

Environment International, Mar 1, 2003

As is well known, a powerful earthquake along the North Anatolian Fault struck the eastern part o... more As is well known, a powerful earthquake along the North Anatolian Fault struck the eastern part of the Marmara region on August 17, 1999. Izmit Bay, which is known as one of the most polluted sites of Turkey, was also affected by the quake and the subsequent refinery fire. The measurements performed just before and after the earthquake showed that T-PAH levels increased significantly after the event [Okay OS, Tolun L, Telli-Karakoç F, Tüfekçi V, Tüfekçi H, Morkoç E. Izmit Bay (Turkey) ecosystem after Marmara earthquake and subsequent refinery fire: the long-term data. Marine Pollution Bulletin 2001;42:361-9]. In the framework of ecotoxicological studies, the Bay ecosystem was continuously monitored for T-PAH levels in seawater, sediments and mussels (Mytilus galloprovincialis) to find out whether change occurred during the 2-year period following the earthquake. For that purpose, after the earthquake, the samples were collected six times between the period of September 1999 and March 2001 at coastal stations of the Bay situated away from the mouth of main discharges. The responses of the mussels were also measured by means of the lysosomal stability of the blood cells and feeding rate biomarker techniques at two different sites of the bay. Although the T-PAH levels in all matrices generally showed a decreasing trend, they were found to be still high especially at stations near the refinery. Both biomarker results showed that the health status of the mussels is very poor in the Bay ecosystem, based on the results obtained from the two sites monitored.

Research Square (Research Square), Jun 29, 2023

The Black Sea is a signi cant European watershed, more productive than the nearby Mediterranean, ... more The Black Sea is a signi cant European watershed, more productive than the nearby Mediterranean, with dynamic wetland habitats along the shore and at the river mouths. Seasonal dynamics that sustain food webs that are adapted to the brackish, nutrient-rich environments are determined by the physiochemical conditions. River discharges carry phosphorus and nitrogen ions with high molar ratios into the Black Sea coasts. The present study evaluated the variations in water quality parameters between the winter season of 2020 and summer season of 2019 at 54 stations representing the two major rivers mounts (the Sakarya and Yeşilırmak), Samsun's port and urban wastewater treatment out ow. Yeşilırmak River showed much higher nitrogen concentrations in the winter (1.46 µM) compared to the summer (0.10 µM). In addition, the Sakarya River nitrogen concentrations were similar between winter and summer seasons. The total phosphorus (2.25 µM) and chlorophyll-a (6.36 µg/L) concentrations were high at Samsun stations in the summer season 2019, where the pressure of urban wastewater is signi cant. The state of pollution, the sources of pollution, and their quantitative contributions in river basins and coastal regions must be determined for effective pollution control and water resource management.

Assessment of marine dredged materials taken from Turkey's ports/harbors in landscaping, 2017

This paper presents the technical usability of marine dredged material (DM) as a manufactured top... more This paper presents the technical usability of marine dredged material (DM) as a manufactured topsoil (MT) in the municipality's landscaping works. In the first part of this study, the physicochemical and toxicological properties and leaching potentials of DMs taken from two sampling points (Istanbul Ambarlı Port and Mersin Erdemli Fishery Harbor) from Marmara and Mediterranean Sea of Turkey were determined and compared pursuant to the National Legislation. In the second part, various improvement studies such as screening, desalination (washing), dewatering, organic amelioration via peat and sheep manure and pH adjustment were carried out on DM samples in order to transform DMs into an alternative natural soil in compliance with the British Standard BS 3882:2015. A total of five different MT mixtures were prepared; then, soil quality and soil nutrient characteristics were examined. Finally, grass seeds were planted into topsoil mixtures, and plant growth performances were followed for 3 months. The results of this study showed that improved DMs can be beneficially used as an alternative MT in order to cultivate grass in municipality's landscaping applications.

Cercetări Marine - Recherches Marines, Dec 20, 2020

Approximately 5x10(6) cubic meter of sediment is removed annually from the harbours, ports, marin... more Approximately 5x10(6) cubic meter of sediment is removed annually from the harbours, ports, marinas and river mouths in Turkey. Uncontrolled dumping of these dredged materials might create contamination based on the assumption that this material is somehow polluted with the human activity related to the surrounding location. Selection of the disposal sites at sea is one of the important steps of dredge material management process described in most of the international conventions

In 7 different region which represent most used harbors, ports and fishing shelters in the Sea of... more In 7 different region which represent most used harbors, ports and fishing shelters in the Sea of Marmara and Black Sea in Turkey coasts. Ecological Quality Status was assesed by sampling soft-bottom macrozoobenthos from 22 stations in 2014.