Bioaccumulation of essential and toxic metals in four different species of bottom fish in the marmara sea, tekirdag, Turkey: Risk assessment to human health

Due to the intensive industrial and agricultural activities in the Thrace region and the maritime transport that directly and/or indirectly affect Tekirdağ coastal areas, the pollution starts from the Tuna River and extends to the Marmara Sea through the Black Sea and the Bosphorus. Heavy metals are not only a threat to marine life, but also to the health of people who consume seafood. In order to investigate the presence of essential and toxic metals in Marmara Sea fish species, samples of 4 different bottom fish (sole, whiting, striped red mullet and angler fish) were collected from 4 different stations in the coastal line of Tekirdağ province in the spring of 2018. Bioaccumulation of essential and toxic metals (Cd, Ni, Cu, Pb, Cr, Mn, Hg, Fe, As, Zn) in the muscles of fish samples was measured by ICP-OES instrument. The accumulation pattern of the analyzed metals in all bottom fish muscles was as follows: Fe (58.8) > Zn (23.9) > Mn (3.3) > As (1.44) > Cu (0.8) > Cr (0.6) > Ni (0.3) > Cd (0.08) mg/kg dry weight. ANOVA analyses indicated significant variations (p < 0.05) of Fe, Zn, Mn, As, Cu, Cr, Ni, and Cd in the muscles of different fish species. Significant variations were observed in different stations (p < 0.05), and As, Pb and Hg were below the detection limit of ICP-OES. Except Cu, the levels of all essential and toxic metals in fish samples were found to be above the national and international legal limits recommended for human consumption. Since the THQ values of inorganic As were higher than 1 mg/kg d·w, it is likely to pose health risk for the consumers of the these fish species. © 2019 Desalination Publications.This study is part of a scientific research project (NKUBAP.23.GA.18.158) at Namik Kemal University. The financial support of the Scientific Research Projects Unit of Namik Kemal University is gratefully acknowledged

Accumulation of essential and toxic metals in sediment from the marmara sea along tekirdağ coast: Risk assessment for ecological health

In our study, sediment samples were collected from four different stations in the spring of 2018 to reveal the presence of essential and toxic metals in the Marmara Sea along the coast of Tekirdağ. Concentrations of essential and toxic metals in sediments of Cd, Ni, Cu, Pb, Cr, Mn, Hg, Fe, As and Zn were measured with an inductively coupled plasma optical emission spectroscope device. The mean essential and toxic metal contents of sediment samples were determined as Fe (10,646.65 mg/kg) > Mn (265.03 mg/kg) > Ni 20.46 mg/kg) > Zn (18.63 mg/kg) > Cr (16.34 mg/kg) > As (11.94 mg/kg) > Pb (5.22 mg/kg) > Cu (3.8 mg/kg) > Cd (2.3 mg/kg). Hg could not be determined because it is in the below detection limits. The potential ecological risk index was calculated for all the metals, except for Hg, in four locations. In the sample SDM1 considerable risk for Cd was detected, moderate risk was found in SDM2 sample and low risk was detected in SDM3 and SDM4 samples. No other ecological risk was found for other metals. The reason for the very high ecological risk was calculated for cadmium might be that cadmium has high toxicity coefficient compared to other metals and due to the use of phosphorous fertilizer containing cadmium in agricultural activities and activities in the field of industry affecting natural water flows, erosion or discharges passing through the Marmara Sea along the coast of Tekirdag province. © 2019 Desalination Publications. All rights reserved.Firat University Scientific Research Projects Management Unit, FÃœBAP: NKUBAP.23This research was funded and supported by Tekirda? Nam?k Kemal University Scientific Research Projects (Project no: NKUBAP.23.GA.18.158).This research was funded and supported by Tekirdağ Namık Kemal University Scientific Research Projects (Project no: NKUBAP.23.GA.18.158)

Office Rent Determinants Utilising Factor Analysis—A Case Study for İstanbul

In recent studies, a wide range of variables has been suggested for modelling the variation in office rent. However, only a few of them are found to influence the explanatory power of the model significantly. Moreover, the significance of these variables varies from model to model, depending on the characteristics of the region or/and the model. It is well established that the regression model of complex phenomena do not perform well, unless the effects of all major determinants are adequately represented. It is also known that complex phenomena may involve a large number of variables, and linear regression models often becomes cumbersome as the number of variables increases. A practical solution to the problem may be to pre-select the significant variables, and leave the less influential ones out. An even better solution could be to include all or most variables, while incorporating the group effect of some variables into a reasonable number factor variables. This way, both the accuracy and practicality of the model can be sustained. Serving this purpose, ‘Factor Analysis’ has been employed in establishing the office rent model for the metropolitan area of İstanbul. The results of four different versions of the model, using linear and non-linear regressions are discussed. Copyright Springer Science + Business Media, LLC 2006Office rent, Prediction model, Factor analysis,