Baseline Preliminary assessment of metal distribution in the surface sediments along the coastline of the southern Caspian Sea Siamak Jamshidi ⁎, Kazem Darvish Bastami Iranian National Institute for Oceanography and Atmospheric Science (INIOAS), No. 3, Etemadzadeh St., Fatemi Ave., 1411813389 Tehran, Islamic Republic of Iran abstract article info Article history: Received 17 September 2016 Received in revised form 15 November 2016 Accepted 12 December 2016 Available online xxxx In the present study, the concentrations of metals in sediments along the coastline of the southern Caspian Sea were investigated. For this purpose, sediments were collected from 13 sampling sites in the southern Caspian Sea. The samples were then analyzed by inductively coupled plasma-optical emission spectrometry. Results showed that compound oxides may be responsible for the distribution of metals in the sediments of the southern Caspian Sea. According to mean effects range-median quotient, 61.5% of the studied sites from the southern Caspian Sea had a 21% probability of metal toxicity. On the basis of the enrichment factor, all metals were in the category of deficiency to minimal enrichment. Pollution load index showed that the other sampling sites had no pollution. © 2016 Published by Elsevier Ltd. Keywords: Metals Coastline ERM quotient Sediment Caspian Sea An increased number of industries brings countless benefits, but is unfortunately associated with critical issues such as environment pollu- tion. The pollution of aquatic ecosystems with metals is an important issue that has been recently linked to the development of industries, and several studies (De Mora et al., 2004; Bastami et al., 2015) have been conducted in this context. Various anthropogenic activities cause entry of these pollutants into the aquatic ecosystem (ElNemr et al., 2007; Bastami et al., 2015). These elements enter through direct and in- direct discharge caused by runoff such as rain runoff and through atmo- sphere. One of the most important properties of metals is that they are nondegradable. The sediments act as pollutant reservoir and accumu- late pollutants from different sources. The amount of metals in the sed- iments depends on various factors such as organic matter, grading of sediment, pH, and redox potential. Changes in these factors affect the amount of metals present in the sediments (Hakanson, 1980; Wright and Mason, 1999; Tam and Wong, 2000; Buccolieri et al., 2006; ElNemr et al., 2007; Bastami et al., 2012; Bastami et al., 2015). In general, normal concentrations of some metals such as copper and zinc are nec- essary; however, when the concentrations of metals exceed beyond the normal levels, they cause damage to the aquatic organisms. The Caspian Sea is surrounded by five countries, namely Iran, Azerbaijan, Russia, Ka- zakhstan, and Turkmenistan, which are important from ecological and geopolitical point of view. More than a hundred big and small rivers discharge into the Caspian Sea, but the most important supplier of water to the Caspian Sea is the Volga river. Oil activities in Azerbaijan play an important role in the pollution of the Caspian Sea. The aim of the present study was to survey the amount of metals in the sediments along the coastline of the southern Caspian Sea and to determine the correlation between the distribution of metals and the characteristics of sedimentology. To survey the sedimentology characteristics and determine the amount of metals in the sediments along the coastline and at the inlet of the river that discharges into the Caspian Sea, 13 stations were select- ed during winter (February) 2016 (Fig. 1). The samples were collected using a Van Veen grab sampler. The samples were then poured into a plastic container and were transferred to the laboratory for recording the characteristics. In the laboratory, the samples were initially dried and then crushed and powdered to remove the coarse particles (Bastami et al., 2015). The analysis of metals was performed according to ASTM standard practice D5258-92 (ASTM, 2013), i.e., 0.5 of sample was digested using HF-HCl-HNO 3 -HClO 4 . The concentrations of metals were measured by inductively coupled plasma-optical emission spec- trometry (Varian VISTA-MPX). In addition, the concentrations of metal oxides were measured by X-ray fluorescence spectrometry (Bruker Model). It was used as the standard reference material to determine the accuracy of measurement. The measured recovery values were be- tween 93% and 108%. The organic matter concentration was measured by the loss of ignition method. Briefly, the sediment was dried in the oven at 72 °C for 24 h and then was burned in the oven at 550 °C for 4 h. The Marine Pollution Bulletin xxx (2016) xxx–xxx ⁎ Corresponding author. E-mail address: si.jamshidi@gmail.com (S. Jamshidi). MPB-08252; No of Pages 7 http://dx.doi.org/10.1016/j.marpolbul.2016.12.033 0025-326X/© 2016 Published by Elsevier Ltd. Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Please cite this article as: Jamshidi, S., Bastami, K.D., Preliminary assessment of metal distribution in the surface sediments along the coastline of the southern Caspian Sea, Marine Pollution Bulletin (2016), http://dx.doi.org/10.1016/j.marpolbul.2016.12.033