Characterization of PAH sources and organic content in sediment particle size fractions in Gemlik Bay (Sea of Marmara), Turkey

Ünlü S., ALPAR Ş. B., Akbulak C., Aydın Ş., Balkıs N.

General Assambly of the European Geosciences Union, Austria, 1 - 04 April 2005

  • Publication Type: Conference Paper / Full Text
  • Country: Austria
  • Istanbul University Affiliated: Yes


Even the environmental threat due to the recent increment in levels of Polycyclic Aromatic
Hydrocarbons (PAHs) in the sediment of Gemlik Bay, a semi-enclosed marine
environment in the Sea of Marmara, is well known; no systematic data was available
for evaluating PAH contamination levels and their sources. It was therefore deemed
necessary to set up a monitoring program to determine the current concentrations of
PAHs in surface sediments. A total of 72 surface samples, mainly scattered along
the coastal areas, were recovered and analyzed for parent and alkylated PAH. Analysis
was performed by gas chromatography coupled to mass spectrometry (GC/MS).
Composition, areal distribution, contamination levels and probable sources of PAHs
were determined. The total PAH load changes from 10 to 590 μg/g (dry weight), being
higher along the east and south coasts. The highest concentrations were determined
in and offshore sea ports of Gemlik and Mudanya and in the inner harbour of a resort
village, Tirilye. The PAH concentrations were generally affected by the chemical
composition of the sediments such as organic matter and clay content. However, in
Gemlik Bay, it is suggested that the distribution and concentrations of PAHs in sediment
would be defined by direct inputs, rather than by the sediment type itself. In
addition correlations between concentrations of PAHs and the content of organic carbon
were established. Pyrolytic and petrogenic sources have been found in the bay.
Mostly in front of the industrial harbours it is exhibited a mixed pattern of petrogenic
and pyrogenic inputs. The intensive anthropogenic activity leads to the introduction of
contaminants in the bay which is subject to high anthropogenic pressure due to inputs
from coasts, rivers, combustion processes through run-off, atmospheric input, industrial
and sewage discharges refined products (e.g. petrol) and shipping activities. The
results form this first scientific data base on which future works will be constructed
and should be utilized in urgent rehabilitation studies especially around the harbours
of Gemlik and Mudanya.