Investigation the history of heavy metal pollution and background values of the Gemlik, İzmit bays using core sediment

In this study, heavy metal pollution history and the degree of pollution status of Izmit and Gemlik Gulfs were investigated using two sediment cores (IZ17, IZ30) from İzmit Gulf and three sediments cores (MD89A, MD88, MD22A) from Gemlik Gulf. The heavy metals background values of core sediments were determined by sedimentological and geochemical analysis. In this context, total organic carbon (TOC), total inorganic carbon (TIC), grain size, total mercury (THg), and mineralogical analysis were performed. Geochronology of heavy metal pollution in core sediments from Gemlik and İzmit Gulf were investigated by C-14 age dating. Background and average (in parenthesis) heavy metal concentrations of IZ17 core sediments were 71947,5 (73010 Al),177,2 (150,3 Cr), 19 (19,7 Co), 28,7 (35 Cu), 74 (122,7 Zn), 27,3 (28 As), 30 (43,8 Pb), 2009 (2184,4 Mn), 78,6 (81,5 Ni), 0,1 (0,4 Hg) and 45495 (47608,5 Fe) mg.kg-1 while of IZ30 core were 22119 (19900,5 Al), 43,4 (62,5 Cr), 5 (3,9 Co), 8,5 (11,7 Cu), 20,5 (27,6 Zn), 4,1 (3,5 As), 11,5 (17,7 Pb), 124,6 (109,6 Mn), 0,1 (1,1 Hg) and 12,5 (11,3 Ni) mg.kg-1. C-14 age date show that the core deposits of IZ17 have been moderate enrichment with Cu and significant enrichment with Zn and Pb since ~1965. The MD22A, MD89A, and MD88 cores taken from different locations of Gemlik Gulf from -38, -38, and - 68 m water depths, respectively. Metal background and average values (in parenthesis) for MD22A were; Al: 27373,8 (20519), Ni: 81 (141,9), Cr: 92,5 (139,7), Cu: 31,7 (40), Zn: 48,3 (95,2), Pb: 19,4 (37,3), Co:16,7 (24,4), Hg: 0,07 (0,1), for MD89A; Cr: 103,3 (99,1), Co: 22,3 (21,2), Pb: 21,2 (24,8), Cu: 32,8 (37,4), Zn: 65,6 (71,2), Mn: 243 (208,3), Hg: 0,08 (0,1) for MD88; Al: 23958 (23902), Cr: 96,3 (72,8), Mn: 321,6 (236,9), Co: 5,3 (7,2), Cu: 5,9 (8,9), Zn: 35,3 (36,1), As: 8,7 (7,1), Hg: 0,06 (0,08), and Pb: 19,3 (32,7) mg.kg-1. According to the C-14 age data, date of the starting anthropogenic pollution was 1788.