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Öğe Distribution, sources and ecological risk assessment of metals in Kura river sediments along a human disturbance gradient(Taylor and Francis, 2021) Kukrer, Serkan; Tunc, I. Onur; Erginal, Ahmet Evren; Bay, Ozender; Kilic, SerefMonitoring the pollution status of freshwater resources is an important step in sustainable planning. This study aimed to determine the distribution and sources of metals in the sediments of the transboundary eastern Anatolian/Caucasus region Kura river as well as its ecological risk level. Surface sediment samples were collected from eight sites along the human disturbance gradient. Multi-element analyses of the collected samples were performed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Chlorophyll degradation product (CDP) analysis was performed spectrophotometrically. OC analysis was carried out using the titration method. The data obtained were evaluated using the indices of enrichment factor, geo-accumulation, modified hazard quotient and ecological contamination index and potential ecological risk. The average content of metals in the sediment at the eight sites was of the following descending order from highest to lowest: Al > Mn > Zn > V> Ni > Cr > Cu > Co > Pb > As > Cd > Tl > Hg. According to the distribution of raw metal values, urbanization is not the only factor controlling metal distribution. Adsorption processes and organic material content also emerge as an important factor. Enrichment factor values were of the following order: T1 > Pb > Mn > Hg > Cr > Co > Cd > Ni > As > Zn > Al > Cu > V. Results revealed that the sources of Cu, V and Al were lithogenic, in contrast to Tl, Pb, Mn, Hg, Cr, Co, Cd, Ni, and As, thus pointing to human-induced accumulation. According to the potential ecological risk index, these elements have the potential to create medium-to-high level ecological risks and were substantially of atmospheric origin. The ecological contamination index is also consistent with these findings in terms of risk level. A municipal waste stream, fossil fuel burning and a cement plant operating in close proximity also appeared to be the possible sources.Öğe Ecological risk assessment of surface sediments of cardak Lagoon along a human disturbance gradient(Springer, 2020) Kukrer, Serkan; Erginal, Ahmet Evren; Kilic, Seref; Bay, Ozender; Akarsu, Taylan; Oztura, ErdalLagoons are the hotspot ecosystems whose sustainability should be secured using the ecological assessment indicators. This study aimed to quantify the surface sediment metal distributions of cardak Lagoon in the Marmara region of Turkey, to characterize their natural and anthropogenic sources and transport mechanisms and to assess their potential ecological risks. The surface sediment samples were collected from 11 stations using Van Veen grab, while for the background values to be determined, core sampling was used from two stations. The analyses of multiple elements, total organic carbon, carbonate, and chlorophyll degradation by-products were carried out to characterize sediments. Enrichment factor and the indices of potential ecological and toxic risks were applied to assess the ecological status of the surface sediments. The operation of the gold mine in the close vicinity was found to be responsible for the enrichment of Au and Hg in the lagoon sediments. Cd, Tl, Sb, and Sr were the other elements responsible for the enrichment. The potential risk levels of the lagoon varied between the low and significant levels. The riskiest elements were found to be Hg and Cd which in turn pointed to the mining and agricultural activities as the most dominant human disturbance. The toxic risk index of cardak Lagoon was estimated to range from 5.21 to 11.00, with a low mean value of 7.98. The C:N ratio range of 8.52 to 134.93 (a mean of 29.07) indicated that the organic C source was mostly of the terrestrial origin, in particular, from the surrounding agricultural lands.Öğe Environmental impact of potentially toxic elements accumulated in surface sediments of the Erikli Lagoon, Black Sea coast (Turkiye)(Walter De Gruyter Gmbh, 2024) Kukrer, Serkan; Uludag, Musa; Erginal, Gulsen; Erginal, Ahmet EvrenThis study aims to (a) determine the concentration and distribution of elements in the surface sediments of the Erikli Lagoon, which are under natural and anthropogenic pressure, (b) determine possible effects on the environment using ecological indices, and (c) reveal possible sources. Multiple elements, total organic carbon and chlorophyll degradation products were analyzed in sediment samples. Enrichment factor (EF), contamination factor (CF), and geoaccumulation index (Igeo) were calculated to determine the sources of the elements. Modified hazard quotient (mHQ), ecological contamination index (ECI), contamination severity index (CSI) and potential ecological risk index (PERI) were calculated to determine ecological risks. It was found that Mn, Hg, As, Fe and Cd entering the lake are of anthropogenic origin. These elements pose a low to moderate ecological threat to the lake. Agricultural and domestic discharges and atmospheric deposition are the main sources of these elements. A moderate ecological risk with an average value of 194.89 was determined in the lagoon based on PERI and contamination levels of metals. The elements that pose this risk are Hg and Cd, due to their high toxicity. According to ECI and CSI, the ecological risk is low, with average values of 0.99 and 0.30, respectively.Öğe Historical record of metals in Lake Kucukcekmece and Lake Terkos (Istanbul, Turkey) based on anthropogenic impacts and ecological risk assessment(Taylor & Francis Ltd, 2019) Kukrer, Serkan; Cakir, Caglar; Kaya, Hakan; Erginal, Ahmet EvrenThe objective of this study was to determine the vertical distribution of metals and organic carbon in lakes Kucukcekmece and Terkos, which are located in different areas near Istanbul and are affected by different environmental factors. The aim was also to specify the metal input, its sources, and the ecological risk over the last 700 years. For analysis, core sediment samples were taken from the bottom of each lake, sliced into 2-cm sections, and analyzed for multiple elements, organic carbon, carbonate, and chlorophyll degradation products. It was determined that Lake Kucukcekmece is threatened by domestic and industrial pollution. To solve this problem, a treatment plant was commissioned in 2012 for the treatment of urban and industrial wastes. In addition, natural gas has been the preferred fuel for the last two decades in Istanbul and this has changed the pollutant profile. On the other hand, Lake Terkos faces possible risks of Mn, P, and As inputs because of fertilizer use in nearby agricultural fields.Öğe Termination of Little Ice Age in Northeastern Anatolia: A Multi-proxy Paleolimnology Study of Lake Aygir Sediments, (Kars, NE Anatolia)(Tmmob Jeoloji Muhendisleri Odasi, 2022) Erginal, Ahmet Evren; Yakupoglu, Nurettin; Cakir, Caglar; Akbas, Abdullah; Kukrer, SerkanSedimentary, geochemical and stable isotope analyses of a sediment core (core AY) recovered from Lake Aygir (NE Anatolia) provide evidence of the climatic shifts during the last similar to 500 yrs. Sediments in Lake Aygir are composed of silty clay with a modeled similar to 0.16 cm/yr sedimentation rate. Multi-proxy analyses of the downcore distribution of detritally-deposited proxy elements, total calcium carbonate, organic carbon and stable isotopes reveal climatic records of the Industrial Epoch (IE; 18th-19th centuries) and the termination of the Little Ice Age (LIA; AD 1350 to 1850), represented by fluctuating Total Organic Carbon (TOC), Ca, Sr and relatively low detrital precursors (Fe, Ti, K, Rb, Zr), indicating low chemical weathering and dry conditions. The upper part of the core (192 cal yrs BP to present), identified with high detrital input, contains an increasing trend of Fe, Ti, K, Rb, and Zr together with high delta O-18 and delta C-13 values, indicating warmer conditions during the IE.
