In this study, ecological risks arising from the accumulation of some heavy metals in surface sediments of Lake Tortum are discussed based on the use of ecological indices, such as enrichment factor (EF), contamination factor (CF), pollution load index (PLI), potential ecological risk index (PER) and the mean probable effect concentration quotient (mPEC-Q). Sediment samples were collected from six different sites using Van Veen grab and heavy metal and organic carbon content of sediments were determined. Results testify to the existence of minimal to moderate contamination in lake sediment. The highest value for the enrichment factor pertains to Cd caused by the use of fossil fuels in settlement areas in the lake catchment. PLI and PER estimations, on the other hand, reveals the presence of low heavy metals-induced ecological risk in lake sediments. Ranging between 15% and 29%, mPEC-Q values are indicative of the fact that Lake Tortum is a low-moderate priority site in terms of toxicity level caused by heavy metals.

Determining the potential bioavailability of heavy metals, evaluating according to adapted regulations is essential to efficiently conserve our coastal and estuarine waters. In this study, it is aimed to determine the industrial pollution and various other pollution sources that the Black Sea Basin is exposed to by using DGT (Diffusive Gradients in Thin Films) method and grab (manuel) sampling method in water and sediment and to evaluate the existing pollution according to quality standards. In Samsun, seasonal samples were collected from five different sampling stations, namely Akkiraz Stream, Hıdırellez Stream, Organized Industrial Zone (OIZ) Channel, Şabanoğlu Stream and Selyeri Stream, which are selected from Tekkeköy region where industry is intensively active. In order to determine the heavy metal content in both water and sediment samples, the DGT method was chosen for passive sampling and the grab sampling method was used for active sampling, and the efficiency of the methods was evaluated. According to the results of the study, the heavy metal concentration in grab sampling for water samples in descending order Al> Fe> Zn> Pb> Ni> Cu; In the samples taken with DGT, they are listed as Al> Fe> Zn> Cu> Ni> Pb. There were significant relationships between the total metal concentrations of sediment (Csed) and water (Csu) in grab sampling and metal concentrations sediment (Csed-DGT) and water (Csu-DGT) measured by DGT. It was found that the sensitivity and performance of sampling with DGT was 2-10 times higher compared to grab sampling. The high resolution in situ DGT technique for the assessment and management of the potential release risk of heavy metals at the water-sediment interface is a complementary method that contributes to the standard grab sampling method.

Sediments in aquatic systems are often contaminated by various pollutants originating from the sources such as industrial and agricultural discharges, municipal wastewater treatment plants, and storm water. These effects lead to the need to develop sediment quality objectives regarding the protection of aquatic ecosystems and human health. In this study, the sediment samples were collected from five sampling sites and then analyzed in order to identify the concentrations of certain metals (As, Se, Ag, Cd, Na, and K), the levels of pH, conductivity, water content (%) and organic matter (%) in the Yağlıdere Stream. Finally, Geo-accumulation index values calculated based on the estimations regarding the background trace element concentrations suggested the anthropogenic influences in most of the samples. In conclusion, it was observed that K, Na, As, and Se dominantly accumulated in the study area. These metals may have a negative impact on the research area and create an environmental risk.

Carrying between February 2012 and February 2013 as seasonal, the present study aims to determine heavy metal loads of five different creeks pass through Giresun city center and disembogue to Black Sea. Heavy metal analyses were performed from selected stations by ICP-MS instrument. Without seasonal and station differences, metal levels were found as follow; Cd: 0.129-5.113, Mn: 0.009-2.937, Fe: 0.007-1.985, Cu: 0.002-1.344, Zn: 0.002-1.901, Ni: 0.003-0.149, Pb: 0.009-21.22, Cr: 0.002-0.177, Co: 0.001-0.087 mg/L in water. Cd: 0.118-166.3, Pb: 5.62-398.9, Mn: 111.7-988.2, Fe: 2919-117973, Cu: 18.60-963.9, Zn: 11.09-2471, Ni: 11.29-813.1, Cr: 10.76-860.5, Co: 8.59-757.1 mg/kg in sediment. There were statistically significant differences between seasons in sea water. Statistically differences were found on Aksu, Güre, and Batlama stations. In sediment, statically differences in Cu, Zn, Ni, Co levels were found in winter season. The same elements were also statistically different on Güre station.