Naim Sezgin

Determination of heavy metal concentrations in street dusts in Istanbul E-5 highway

Components and quantity of street dust are environmental pollution indicators especially in big cities. Street dust is generally composed of car exhaust gas originated particles and wind-transported particles. Heavy metals, which are found in street dust, such as Pb, Cu, Mn, Zn, Cd and Ni are significant for environmental pollution. According to the kind of vehicle in traffic, quantity and type of heavy metals vary in street dust. The use of leaded gasoline gives a boost to the importance of lead level especially in street dust even at the start of 21st century. These metals possess bioaccumulation property, and the possibility of the amount of these metals reaching a critical value and threatening human health increases the importance of this issue. In this study, street dusts have been collected from E-5 Highway from Topkapi to Avcilar regions that spans about 18 km in Istanbul, Turkey, and Pb, Cu, Mn, Zn, Cd and Ni concentrations have been detected in street dust. Twenty-two street dust samples were taken from a total of 22 different points at previously decided 14 main areas. Analyses were conducted using Leeds Public Analyst method. According to the results of this study, Pb, Cu and Zn concentrations in E-5 Highway between Topkapi and Avcilar region in Istanbul were higher than maximum concentration levels of these heavy metals in normal soil. This situation indicates that there is heavy metal pollution in the inspected area in E-5 Highway in Istanbul.

Investigation of horizontal cold water discharge initial dilutions at various temperature differences using duckbill valve

AbstractThermal pollution, that is a temperature change in natural water body, can have adverse effects on the organisms in the aquatic environment as river, lake, or ocean. A common cause of thermal pollution is the use of water as a cooling and heating system by power plants, liquefied natural gas (LNG) regasification terminals, and industrial manufacturers. Cold water discharges into a receiving water body, which are mainly originated from LNG regasification terminals from open cycle heating units, are a kind of thermal effluent. Disposal of cold water with an environmentally protective way can be applied as a dilution method using marine outfall systems. In order to obtain a better dilution in a marine outfall, there is a multiport diffuser at the end of the pipeline. Experimentally performed single port analysis of an outfall is a method of initial dilution investigation for performance determination of designed system. Because of the fact that cold water discharge is denser than receiving ambient wa...

Water depth effects on initial dilution of horizontally discharged cold water from an elevated outfall

In this study, the effect of bottom depth interaction on initial dilution differences of cold water discharge was experimentally investigated. 5°C cooled and dye tracer added cold water were horizontally discharged from a submerged circular nozzle from an elevated position into a stagnant and homogeneous receiving water in an experimental tank. Minimum initial dilutions were measured in cold water jet centreline in jet body and density current. Jet boundaries and geometric parameters were obtained from instantaneous image series of cold water jets. According to this study, for 24.54% decrease of normalised nozzle-bottom distance, y0/dF, normalised impact point distance, xi/ dF was 24.43% decreased, and normalised impact point dilution, Si/ F was 13.65% decreased.

Ecological Risk Assessment of Heavy Metal Pollution in Urban Soils: A Case Study

In this study, geo-accumulation index (Igeo), enrichment factor (EF), potential ecological risk (Er), and risk index (RI) of five metals (Cu, Pb, Zn, Hg, and Cd) and Sc (as reference element for enrichment factor calculation) in soil samples were applied for assessing the pollution pattern and possible sources of heavy metals. Soil samples were collected from 27 different locations in Avcilar in the European part of Istanbul, Turkey. The mean Igeo values of Cu, Pb, Zn, Hg, and Cd were found between 0.12 and 0.96, which means that the soil contamination levels of these metals were uncontaminated to moderately contaminated. The EF mean values of Cu, Pb, Zn, Hg, and Cd were 1.70, 1.30, 1.30, 2.29, and 1.26, respectively. These EF results indicated that Cu, Pb, Zn, and Cd in the study area soil were affected by natural sources, whereas Hg was mainly caused by nature and partly influenced by human activities. The order of the mean values of Er in the soil samples was in the following descending order of Hg > Cd > Cu > Pb > Zn. Most of the soil samples showed low and moderate ecological risks.

Natural Radioactivity and Hazard Level Assessment of Cements and Cement Raw Materials

Cement is a composite material and it consists of different raw materials. The raw materials which are used in the cement production industry are commonly obtained from rocks such as limestone, gypsum, clay, and iron ore. In addition, the cement raw materials may also include natural radionuclides such as 226Ra, 232Th, and 40K, which may have an adverse effect on human health. Hence, determination of natural radioactivity level is very important for human health safety. In this study, natural activity concentrations of 226Ra, 232Th, and 40K are investigated in cement and cement raw materials in Turkey as a case study. In addition, eight different radiological parameters and indices were calculated from activity concentrations. The natural radioactivity due to the presence of 226Ra, 232Th, and 40K was measured using the gamma spectrometer coupled with HPGe detector. The mean measured activity concentrations of 226Ra, 232Th, and 40K in the raw materials were 38.14, 92.66, and 636.63 Bq kg−1, respectively, with higher activity concentrations in coal for 226Ra and trass for 232Th and 40K. Mean activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) in cement samples were found as 34.26, 58.2, and 512, respectively. The results showed that coal and fly ash are the principal contributors for the presence of 226Ra activity concentration, trass and iron ore materials for the presence of 232Th, and clay and trass raw materials for the presence of 40K in cements.

An investigation on initial dilution of thermal wastewater discharges into shallow receiving waters with 60° inclination

In this study, effects of shallow water depths on initial dilution levels of heated water discharge from thermal effluent outfalls concerning water surface boundary effects using an inclined circular port were investigated. Receiving water environment was selected as stagnant and uniform characteristics. The inclination angle of discharge port was θ = 60°. Normalized port depths, H/dF, which was obtained from water depth (H) over port diameter (d) multiplied by densimetric Froude number (F) of jet defined as dF, were calculated for experimental set-ups. H/dF values were 3.871, 1.545, 1.160, 0.774, and 0.388 from deep to shallower depths, respectively. Rhodamine B was used as tracer of experiments. Normalized forms of impingement point horizontal distance values, xi/dF, and vertical distance values, yi/dF were decreased according to decreased water depths, H/dF. According to obtained results of this study, jet impingements occurred in the upper boundary of the receiving water body and they got closer to the nozzle when H/dF values decreased. In addition, the decreasing H/dF values caused a decrease in dilutions of horizontal distances for both complete jet centerlines (especially impact points compared to experimental) and VP estimates of free jet conditions. According to this study, VP dilution estimations were found very close to experimental impingement point dilutions no matter how VP software originally designed for only free jet conditions. This study suggests VP UM3 model can calculate realistic and conservative jet centerline dilutions at the impingement point in very limited depths in the range of normalized water depth ratio H/dF between 0.388 and 1.545.