@article{article_1928332, title={Index-based evaluation of organic and heavy metal pollution in surface waters of Lake Mogan (Ankara, Türkiye)}, journal={Ege Journal of Fisheries and Aquatic Sciences}, volume={43}, pages={241–250}, year={2026}, DOI={10.12714/egejfas.43.3.07}, url={https://izlik.org/JA76MT66UM}, author={Sayın, Semih and Pulatsü, Serap}, keywords={Kirlenme, organik kirlenme indeksleri, ağır metal indeksleri, yüzey suları, Mogan Gölü}, abstract={<p>This study aimed to estimate organic pollutants and heavy metals in the surface waters of three stations in Lake Mogan, during dry and rainy periods, using a set of indices. Lake surface waters; (a) Based on Organic Pollution Index (OPI) values (0.78–1.89), are classified as “Beginning to be polluted” and exhibit a eutrophic nutrient level (Eutrophication Index (EI): 1.09–14.55), (b) The average heavy metal concentrations across all stations during the dry period followed the order Fe > As > Ni > Pb > Cr > Cd > Cu, while during the rainy period they were Fe > As > Ni > Cr > Zn > Cu, (c) As (max.: 67 µg/L) and Fe (max.: 612.04 µg/L) concentrations exceeded the Environmental Quality Standard (EQS) values at all three stations in both periods, whereas Cd (> 0.72 µg/L) and Pb (> 2.5 µg/L) exceeded the limits recommended for aquatic life during the dry period, (d) Heavy Metal Pollution Index (HPI) indicated “Moderate – High pollution” at all stations during the dry period, while during the rainy period, HPI and Heavy Metal Evaluation Index (HEI) levels at all stations were classified as “Low pollution.” According to the Potential Ecological Risk (PER) values, all stations were identified as “low risk” in terms of EQS during the rainy period, and also as “low risk” for aquatic life at all stations during dry and rainy periods, (e) While the potential source of organic pollution was determined to be residential areas, the sources of Fe, As, and Ni - identified as the primary metals threatening lake health - were found to be a combination of discharges originating from andesite stone processing facilities, residential areas, and agricultural activities. The results indicate the necessity of including eutrophication management in the basin’s strategic plan and implementing long-term measures particularly targeting mining activities. </p>}, number={3}