Monitoring of heavy metals in macroalgae from the Turkish coast of the Aegean sea

Marine organisms were evaluated as possible biomonitors of heavy metal contamination in marine coastal areas. The concentrations of different metals (Hg, Cd, Pb, Cr, Cu, Zn and Fe) were measured in red, brown and green macroalgae species seasonally at eight coastal stations along the Turkish coast of the Aegean Sea. Sediment and seawater samples were also collected from the sampling stations to detect their metal contents in order to gain more information on the environmental conditions of the area and possible bioaccumulation patterns. .The aim of this study is, to gather more information on the use of selected species as cosmopolitan biomonitors for the eastern Aegean; to provide information on the marine environmental quality throughout the use of macroalgae and to determine which algae species are suitable as biomonitoring species for the study area.. Main oceanographic parameters were measured at the sampling stations to evaluate the results more sensitively. The relative abundance of metals in macroalgae decrease in the order: Fe>Zn>Cu>Cr>Cd>Hg>Pb and in seawater: Fe>Zn>Pb>Cu>Cr>Cd>Hg. The distribution order of metals in macroalgae and seawater had the same trend except Pb. In sediment the distribution order was Fe>Cr>Zn>Pb>Cu>Hg>Cd. The highest metal concentrations in seawater were measured from the inner part of the İzmir Bay. The concentrations of heavy metals in sediment samples were lower in the sampling regions than the polluted areas of the Mediterranean Sea. Metal concentrations in macroalgae showed significant correlations with the corresponding ones in seawater and sediment. In all of the macroalgae species Zn and Fe were significantly correlated with each other except for Codium fragile. Regarding net accumulation, Cystoseira and Entromorpha were the strongest accumulators of Cd, Cr, Fe and Hg, Pb, Zn, respectively. Ulva turned out to be the highest Cu accumulator. The brown algae Cystoseira sp., the green algae Ulva sp. and Entromorpha sp. possess high potential as cosmopolitan biomonitors for trace metals in Aegean Sea.