An ecological risk assessment of the impact of heavy metals in surface sediments on biota from the mid‐Black Sea coast of Turkey

Abstract

The effects of anthropogenic activities on the accumulation of heavy metals and other compounds in sediments, mussels (Mytilus galloprovincialis) and water of the mid‐Black Sea coast of Turkey were examined in this study. The aim was to work ecological risk assessment of heavy metals (Cu, Zn, Cr, Cd, Pb and Ni) at surface sediment and mussel samples. Sediment and mussel samples were subjected to a total digestion technique (HNO₃ – HCl – HF conc.) and analysed for selected heavy metals by AAS (Atomic Absorption Spectrophotometry). The general environmental properties of water, sediment and mussel samples were also measured (i.e. BOD₅, organic matter %, mussel dimensions). Sediments were evaluated based on Sediment Quality Guidelines (SQG) and also with ERL/ERM and TEL/PEL values of EPA guidelines. The degree of contamination (C_d) was estimated for each station. The degree of heavy metal contamination of mussel samples was higher in Samsun city harbour. The values of sum of toxic units (Σ TU) for each of the sampling sites based on concentrations of Cu, Zn, Cr, Cd, Pb, and Ni were also calculated. The whole results at sediment, mussel and water samples showed that the mid‐Black Sea coast of Turkey is facing beyond any question heavy metal pollution. To be more specific, high concentrations of Cd and Pb determined at both marine and freshwater samples may indicate a fresh and continuous contamination from domestic and industrial discharges.

Keywords:

• Degree of contamination
• Ecological risk assessment
• Heavy metals
• Mussels
• Sediment quality guidelines
• Surface sediments

Acknowledgement

This work has been supported by Ondokuz Mayıs University research projects MF‐050 and MF‐045 directed by Assoc. Prof. Dr Gülfem Bakan and Ass. Prof. Dr Hülya Böke Özkoç.