Halim Aytekin Ergül

Natural and artificial radionuclide activity concentrations in surface sediments of Izmit Bay, Turkey.

Surface sediments from the north-eastern coast of the Marmara Sea, Turkeys most industrialized coastal region, were enriched with radioisotopes from the Chernobyl explosion in 1986. Caesium-137 in these sediments is also thought to originate from one former paper mill located nearby that used wood contaminated by Chernobyl explosion-originated (137)Cs for paper production. The average activity concentration of the (137)Cs was 21 Bq kg(-1), while naturally occurring radioisotopes, i.e. (40)K, (226)Ra, and (228)Ra, were 568, 18 and 24 Bq kg(-1), respectively, in surface sediments. The natural radionuclide activities reached their highest levels near petrochemical, phosphate and fertilizer processing facilities. Average (137)Cs activities were generally up to ten times higher than in Middle Eastern marine sediments and lower than those in Northern European sediments.

Investigation of heavy metal pollutants at various depths in the Gulf of Izmit

In this study, we report results concerning the accumulation of heavy metals in seawater from Izmit Bay. The bay was divided into the three parts: the eastern, the central and the western basins. The goal of this study was to determine levels of heavy metals at various depths in the bay between April 2008 and May 2010. Liquid-liquid extractions were performed on seawater samples. An atomic absorption spectrophotometer was used to measure levels of six metals: lead, cadmium, chromium, iron, manganese and zinc. We applied our results to evaluate the status of pollution in the Gulf of Izmit. Significant seasonal differences in metal concentrations and higher concentrations of many metals in water near the shore are evidence for uncontrolled release of pollutants in the water.

Assessment of the consecutive harmful dinoflagellate blooms during 2015 in the Izmit Bay (the Marmara Sea)

A series of red tides were observed during 2015 in the Izmit Bay (the Marmara Sea) which is located in the most industrialized and populated region of Turkey. Six samplings were carried out in this area following the red tides. Nitrite-N, nitrate-N, ammonia, silica and orthophosphate concentrations were analyzed spectrophotometrically. Physicochemical conditions were measured by CTD probe. Plankton quantification was performed using counting chambers under microscopes. Prorocentrum micans was the most abundant species, except on May 14, 2015, when Noctiluca scintillans was dominant. The abundance of P. micans reached average 18×106 ind./L on May 3, 2015 in the Karamürsel station, simultaneously with elevated levels of NH3 and o-PO43–. The sample was also abundant in dead amphipods ((72±12) ind./L) that had been covered by mucilage aggregates produced by P. micans. The highest biomass (calculated by carbon) was recorded as (268±26.0) mg/L on May 14 in the Hereke station. Beside the anthropogenic wastewater discharges, unknown sources and resuspensions caused increases in nutrient levels. After long term northeaster gusts (35 km/h for 5 d) an upwelling occurred on November 6, 2015 after wind-induced sediment resuspension. Although nutrient discharges remarkably decreased over 30 years through established wastewater treatment plants, harmful phytoplankton blooms still occur. Comparing the present results with other studies in nearby Mediterranean seas reveals that the most intense harmful dinoflagellate bloom in recent years occurred in the Izmit Bay. Therefore, additional protection measures necessary for a cleaner Izmit Bay. These incidents also demonstrate that contaminants, accumulated in sediment, may have long-lasting effects on enclosed marine ecosystems.

Assessment of Macrophyte Plant Distribution and PAH Contamination in Selected Aquatic Habitats from an Industrialized City; Kocaeli, Turkey

Abstract The macrophyte plant distribution in some aquatic habitats and their availability for monitoring the PAH contamination were investigated in Kocaeli Province of Turkey. Alisma plantago-aquatica L. was collected to evaluate polyaromatic hydrocarbon (PAH) contamination in four aquatic habitats located nearby or distant to the industrial facilities and populated city center. Concentrations of eight PAH congeners were measured in A. plantagoaquatica leaves using gas chromatography. PAH sources were estimated using the following ratios, Fluoranthene / (Fluoranthene + Pyrene), Benzo(a)anthracene / (Benzo(a) anthracene + Chrysene) and Anthracene / (Anthracene + Phenanthrene) and were found to be pyrogenic-sourced in all stations. Since the ratios of congeners indicate the pyrogenic contamination, atmospheric deposition can be considered as the main pathway for PAH transportation. The highest ΣPAH concentration (798 μg kg-1) was measured in the nearest station (Bıçkıdere Dam) to the city center and highway, while the lowest concentration (183 μg kg-1) was determined in the Tahtalı Dam, which is relatively distant from the industrial facilities, dense population and motorways. Present results indicate that incomplete combustion of grass, wood and coal, as well as recreational and agricultural implementations and vehicular emissions, may cause pyrogenic PAH contamination. Also, broad basal leaves of A. plantago-aquatica can be considered as sampling material in further biomonitoring studies.

PAH and PCB Levels in Malva sylvestris L.Specimens Collected from Kocaeli, Turkey

Abstract: In this study, polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) contaminations in the leaf, stem and root tissues of common mallow (Malva sylvestris L.) were investigated by using gas chromatography to give an insight into the bioaccumulation of these persistent pollutants. The sampling stations are located in the Dilovası and İzmit Districts of Kocaeli Province in Turkey. Total PAH concentrations varied between 10.44 and 61.15 pg g-1 dw (dry weight). The most dominant PAH congeners were Acenaphthene and Acenaphthylene which are low molecular weight. Total PCB concentrations were found to be between 326.79 and 4496.42 pg g-1 dw. PCB 66, PCB 110, PCB 153 and PCB 180 were found to be the most dominant congeners. Detected concentrations in root tissues showed the plant’s ability in accumulating these pollutants. Therefore, these findings suggest that Malva sylvestris can reflect the contamination levels which might be used to monitor soil and ecological pollution levels caused by these persistent pollutants.