Paleo Environmental Pollution Assessment of Erdek and Bandırma Bays in the Sea of Marmara, Türkiye

Abstract

Geochemical and sedimentological analyses and C-14 dating of four cores from Erdek and Bandırma Bays were performed to evaluate the metal pollution, history and sources, and content in the southern Sea of Marmara (SoM) caused by industrial, agricultural and domestic activities during the sediment deposition. The selected elements’ pollution (Al, Fe, Mn, As, Co, Cr, Cu, Hg, Ni, Pb, V and Zn) data were evaluated using contamination factor (CF) and pollution load index (PLI). The sedimentary succession in all cores consists mainly of clay (9–96%), silt (1–78%) and sand (0.1–20%) with small amounts of gravel (0.1–7%). The results of CF and PLI reveal that the upper 20 cm core sediments in Erdek Bay were contaminated with Hg (0.07–1.1 mg/kg), Pb (4–72 mg/kg) and Zn (12–255 mg/kg) by both anthropogenic and lithogenic input via the Biga and Gönen streams. Furthermore, the upper 20 cm of MD72 and BK1 core sediments were moderately polluted with As, Cu, Hg, Pb and Zn caused by the discharge of untreated industrial wastewater and domestic sewage from the surrounding area of Bandırma Bay. Moreover, lithogenic Pb-Zn was transported to Erdek Bay by Biga and Gönen streams from the Pb-Zn mineralized zones in the southern SoM drainage area. C-14 dating reveals that As, Hg, Pb and Zn contamination in the study area was started about 400–500 years before the present based on preliminary sedimentation rate estimates and has increased intensely in the last century. Our work is a significant effort to help the environment protection agency or other stakeholders draw a framework to solve this emerging challenge from sewage and wastewater treatment plants.