Organochlorine residue and toxic metal (Pb, Cd and Cr) levels in the surface sediments of the Marmara Sea and the coast of Istanbul, Turkey

Assessment of distribution of heavy metals and activity level of 210Pb in biota from the northern coast of the Marmara Sea and Western Black Sea

In this study, heavy metals (Cd, Co, Cu, Ni, Pb, Zn, V) and ²¹⁰Pb analyses have been performed in the marine biota (scaldfish, sea lettuce, crab). Samples were collected from 5 different parts of the Marmara Sea and Western Black Sea in January 2020. The results indicated that the highest Cu and Zn content was found in algae samples, but it was observed that heavy metal concentrations such as Co, Cu, Cd and V were generally low and under permissible limit. Also, ²¹⁰Pb (radioactive isotope of Pb) activity levels were determined to vary from 23.20 Bq kg^-1 to 52.67 Bq kg^-1 dry weight. It was clearly seen that there was a linear correlation between the toxic and radioactive Pb when the obtained data were compared.

Monitoring the antioxidant activities by extracting the polyphenolic contents of algae collected from the Bosphorus

The identification and quantification of ascorbic acid, phenolic acids and flavonoids were carried out simultaneously with a rapid method of reverse-phase high-performance liquid chromatography (RP-HPLC). Total flavonoid contents were being determined by UV-Vis spectrophotometry, and total phenolic contents were determined by UV-Vis spectrophotometry using the Folin-Ciocalteu Reagent (FCR) method. In all of the individual contents and total phenolic content analysis, the best results were obtained with the methanol-water solvent system. The methanol-hexane solvent system was selected as the best for the extraction of total flavonoid contents. The reason for this difference is the flavonoids in the analyzed samples which were the lipophilic character. Examining the algae species, the highest contents were achieved from Ulva lactuca and Ceramium rubrum species. Depending on industrial activity and the population density, regional characteristics have been shown to be effective in the changes of these contents which show antioxidant properties.

Toxic metal (Pb, Cd and Hg) levels in the nearshore surface sediments from the European and Anotolian Shores of Bosphorus, Turkey

In this study, some toxic metal such as Pb, Cd and Hg analyzes have been done in the nearshore surface sediments. Sediment samples have been collected from five parts from the European and Anotolian Shores of the Bosphorus during 2003-2004. Total Pb, Cd and Hg contents vary between <0.01 μg g(-1) and 238 μg g(-1); <0.01 μg g(-1) and 0.92 μg g(-1); 0.001 μg g(-1) and 0.45 μg g(-1), respectively. Contamination Factor (CF) values of Pb and Cd range between 1 and 3 whilst CF values of Hg are lower than 1 in all the stations. It means that there are no Hg metal enrichment by natural or anthropogenic inputs contrary to moderately contamination for Pb and Cd metals throughout the Bosphorus sediments.