International Journal of Marine Science, 2017, Vol.7, No.22, 205-213
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solutions were analyzed using the ICP-MS method. The ultra-trace Aqua Regia digestion method for Hg analysis
was also used by Acme Labs. Subsamples of 0.5 g were leached in hot (95°C) Aqua Regia and the average values
of the samples were used.
1.4 Analysis of certified reference materials
Sediment samples were analyzed with the quality control. Blanks (analytical and method), duplicates and standard
reference materials inserted in the sequences of client samples provide a measure of background noise, accuracy
and precision. QA/QC protocol incorporates quartz sample-prep blank(s) carried through all stages of preparation
and analysis as the first sample(s) in the job. A reagent blank to measure background and an aliquot of Certified
Reference Material (STD OREAS24P) to monitor accuracy was used as a control for analytical methods.
The analytical concentrations of the metals were within the range of reference values, and the replicate analysis of
samples showed that the variability of the analytical precision was always within the acceptable ranges.
1.5 Organic content
Total organic carbon was measured in surface sediment by drying the samples at 600°C for 4 h. Samples free of
organic matter were also treated by using diluted HCl to remove calcium carbonates and the loss in weight was
again determined, according to the method described by Buchanan (1984).
1.6 Statistical analysis
The data set has been subjected to correlation and factor analysis for elucidating the relationships between the
heavy metals and geochemical characteristics. The geoaccumulation index is calculated to determine metals
contamination in sediments of Sinop Peninsula as the following equations:
I
geo
= log
2
[C
sample
/ (1.5 x C
background
)]
In which, C sample is the measured concentration of samples; C background is the background concentration of
sediments and factor 1.5 is the possible variations of background data due to anthropogenic impacts.
2 Results and Discussion
Levels of the metals in sediments from Sinop Peninsula are given in Table 1, Table 2 and Table 3. Higher amounts
of some metals in sediments from Sinop Peninsula reflect that the sediments act as a settle and source for these
metals. Sediment accumulation rates were around 1 ±0.5 mm year
−1
for the upper 10 cm of the oxic–hypoxic and
the hypoxic-sulfidic zone in the Black Sea (Lichtschlag et al., 2015) and sediments are of fine-grain muddy
composition with a brownish grayish fluff layer on top about 0.5 cm (Jessen et al., 2017). In general results
showed that decreasing of the metal levels with increasing depth of the sediment. This can be explained that the
deep layers are older age than those in the decomposition processes took place for a long time as compared with
the layers above it (Al-Shamsi et al., 2016). The percentage of organic content in the sediment of Karakum,
Akliman and Inner Harbor were 2.5-3, 0.85-1.16 and 0.93-1.31%, respectively.
The normalization of metal concentrations to Al has become an important tool for evaluating elevated metal levels
in natural waters due to anthropogenic activities. The effects of clay fraction are eliminated by keeping the
entering of Al into the marine environment. Therefore, the preferred method for evaluating the heavy metal levels
resulting from activities in natural waters is obtained by dividing each metal concentration by Al (Özkan and
Büyükışık, 2012). The correlations of Al-normalized metals and other variables (P and Ca) are given in Figure 2
and Figure 3.
SQGV are one of the most important and useful tools to save and assay marine ecosystem from adverse effects.
The results compared to those determined by the recommended sediment quality guideline values (SQGV)
(Simpson and Batley, 2016). In the present study, the results were compared with SQGV to get preliminary
information about the metals concentration in surface sediments of Sinop Peninsula in the Black Sea. The levels
of most metals at all stations were lower than the contents indicated by the sediment quality. For example SQGV
