Spectrofluorometric characterization of aromatic hydrocarbon contamination in the sediment from the Zonguldak industrial region, Black Sea, Turkey

The Black Sea is highly vulnerable to pollution due to its geographical setting, layered oceanographic and chemical conditions, as well as the extent of human-induced stress over their coastal environment Inputs of harmful substances, in particular oil, constitute a threat to this semi-enclosed ecosystem, especially in the vicinity of port activities and river discharges. One of the most important hot spot areas is an industry region between the coastal cities of Zonguldak and Eregli, a leading province of Turkey in terms of industrial production. Synchronous excitation/emission scans were evaluated to determine the relative fluorescence and to characterize the type of aromatic hydrocarbons in the samples collected from the western Black Sea shelf of this industrial region in 2005. The fluorescence signals of two reference materials were used; these are 1) chrysene and 2) combined reference material obtained from seven different crude oils (THETIS-OIL) used and transported in the Black Sea region. According to NOAA sediment quality criteria, the surface sediments in the region are mostly contaminated by acutely toxic PAHs which cause serious toxicity. On the basis of the spectra of families representing aromatic structures, hydrocarbon levels show wide-range distribution. Total aromatic hydrocarbon levels ranged from 1.7 to 1588.7 kg g super(-1) with 80.9% exceeding the effects range median (ER-M) of 44.8 kg g super(-1). Highest level of pollutions was observed at two distinct spots offshore the Zonguldak sea port and a cement factory in Eregli; which are 1550-1600 kg g super(-1) and 240-260 kg g super(-1) using THETIS oil and chrysene, respectively. Pyrolytic activity is dominant in the east, offshore the Zonguldak, while pyrolytic activity mixed with petrogenic activity is dominant, especially in the western side of the study area, offshore the industrial town of Eregli.