Combining single and complex indices of pollution with grain size trend analysis of surficial sediments in Edremit Gulf, western Turkey.

Abstract

Pollution risk assessment of heavy metals (Pb, Cr, Cu, Ni, Zn, As) in sediment samples from 68 locations in the Gulf of Edremit, western Turkey, was performed using single and complex indices of pollution assessment approaches. The pollution indices used in the sediment analyses included pollution load index(PLI), contamination factor(CF), contamination degree(Cdeg) for individual metals, geoaccumulation index (Igeo), enrichment factors(EF), toxic risk index(TRI), modified pollution index (MPI), frequency of adverse biological effects (TEL-PEL), percent incidence of biological effects (ERL-ERM), and total risk quotients (QTEL-QPEL). Results indicated a low degree of contamination for the entire surveyed area except moderate contamination factor for arsenic using single indices. Enrichment factors and geoaccumulation indices indicated moderate to significant enrichment and uncontaminated to moderately contaminated both for arsenic(As) and lead(Pb), respectively. According to the results of ecological risk assessment based on TELs and PELs, the adverse biological effects of heavy metals on aquatic organisms; are for As, Cr, Ni frequently, Cu and Pb occasionally and Zn rare. The TRI values displayed low to considerably toxic risk for the entire Gulf and calculated TRI results showed that arsenic accounted for most of the entire sediment toxicity. Transport patterns of sediment grain size trend analyses were correlated with the results of pollution assessment models. Transport trends are compatible with the sources of lithogenic, anthropogenic, mining activities and wastewater treatment/geothermal originated arsenic.

The comparison of population density of Holothuria tubulosa (Gmelin, 1790) and Holothuria polii (Delle Chiaje, 1823) between exploited and non-exploited areas in the Aegean Sea coast of Türkiye

“…While the importance of sea cucumber species in the coastal ecosystem is obvious, ecological problems that exist especially on the shores of the Aegean Sea also threaten these species. Posidonia oceanica meadows, which are crucial for sea cucumber species in our coasts where human activities are very intense (such as İzmir Bay, Çandarlı Bay, Edremit Bay) are withdrawing and their area is decreasing (Duman et al, 2019). Added to this negative picture was the mass death of Pinna nobilis, the largest bivalve and water filtration of the coastal ecosystem, as a result of a disease that spread throughout the Mediterranean in 2017.…”

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“…While the importance of sea cucumber species in the coastal ecosystem is obvious, ecological problems that exist especially on the shores of the Aegean Sea also threaten these species. Posidonia oceanica meadows, which are crucial for sea cucumber species in our coasts where human activities are very intense (such as İzmir Bay, Çandarlı Bay, Edremit Bay) are withdrawing and their area is decreasing (Duman et al, 2019). Added to this negative picture was the mass death of Pinna nobilis, the largest bivalve and water filtration of the coastal ecosystem, as a result of a disease that spread throughout the Mediterranean in 2017.…”