TY - JOUR T1 - Index-based evaluation of organic and heavy metal pollution in surface waters of Lake Mogan (Ankara, Türkiye) TT - Mogan Gölü (Ankara, Türkiye) yüzey sularında organik ve ağır metal kirliliğinin indeks temelli değerlendirilmesi AU - Sayın, Semih AU - Pulatsü, Serap PY - 2026 DA - July Y2 - 2026 DO - 10.12714/egejfas.43.3.07 JF - Ege Journal of Fisheries and Aquatic Sciences JO - EgeJFAS PB - Ege Üniversitesi WT - DergiPark SN - 2148-3140 SP - 241 EP - 250 VL - 43 IS - 3 LA - en AB - 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. KW - Pollution KW - organic pollution indices KW - heavy metal indices KW - surface waters KW - Lake Mogan N2 - Çalışmada, Mogan Gölü’nde üç istasyon yüzey sularında kuru - yaş dönemde olmak üzere, organik kirleticilerin ve ağır metallerin bir takım indeksler kullanarak tahmini amaçlanmıştır. Göl yüzey suları; (a) Organik Kirlenme İndeksi (OPI: Organic Pollution Index) değerlerine göre (0.78-1.89) “Kirlenmenin başladığı” ve ötrofik (Ötrofikasyon İndeksi (EI: Eutrophication Index) : 1.09 - 14.55) besin seviyesine sahiptir, (b) Tüm istasyonlara ilişkin ortalama ağır metal konsantrasyonları kuru periyot için Fe > As > Ni > Pb > Cr > Cd > Cu iken, yağışlı periyot için Fe > As > Ni > Cr > Zn > Cu şeklindedir, (c) As (maksimum: 67 µg/L) ve Fe konsantrasyonları (maksimum: 612.04 µg/L), her iki dönemde ve üç istasyonda Çevresel Kalite Standart (EQS: Environmental Quality Standards) değerlerini, Cd (> 0.72 µg/L) ve Pb (> 2.5 µg/L) ise kuru periyotta sucul yaşam için önerilen sınır değerleri aşmıştır, (d) Ağır Metal Kirlenme İndeksi (HPI: Heavy Metal Pollution Index) tüm istasyonlarda kuru periyot için “Orta – Yüksek kirlenme”, yağışlı periyotta HPI ve Ağır Metal Değerlendirme İndeksi (HEI: Heavy Metal Evaluation Index) tüm istasyonlarda “düşük kirlenme” seviyesindedir. Potansiyel Ekolojik Risk (PER: Potential Ecological Risk) değerlerine göre ise EQS açısından yağışlı periyotta tüm istasyonlarda, - sucul yaşam - açısından da kuru ve yağışlı periyotta tüm istasyonlarda “düşük risk” düzeyindedir, e) Organik kirliliğin olası kaynağı yerleşim yerleri iken, göl sağlığını tehdit eden birincil metaller olarak belirlenen Fe, As ve Ni’in kaynakları andezit taşı işleme tesisleri, yerleşim yerleri ile tarımsal faaliyet kaynaklı deşarjların kombinasyonu olarak belirlenmiştir. Sonuçlar, havzanın stratejik planına ötrofikasyon yönetiminin dahil edilmesinin ve özellikle madencilik faaliyetlerini hedef alan uzun vadeli önlemlerin uygulanmasının gerekliliğini göstermektedir. CR - Aliagha, U.G., & Mustafa, F.B. (2022). Examining seasonality and vertical variability of heavy metals contamination in Urban Lake Malaysia using discriminant analysis. 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