Microplastic (MP) pollution is an increasing concern in marine ecosystems due to the risk it poses to marine organisms and human health. This study aims to investigate the type, abundance, and properties of MPs in five commercially important fish species ( Engraulis encrasicolus , Trachurus trachurus , Sardina pilchardus , Sarda sarda , and Dicentrarchus labrax ) and Mediterranean mussels ( Mytilus galloprovincialis ). In the study, samples were collected from five different regions in the Southern Marmara Sea of Turkey. In addition, the polymer composition of MPs identified in the study was determined and evaluated according to the associated hazard index to determine the potential risks to marine life and human consumers. A total of 1734 MPs were identified in the gastrointestinal tracts (GITs) of fish samples ( n = 660), while 650 MPs were identified in mussel samples ( n = 50). The analyses revealed that there was significant interspecific and spatial variability in MP abundance, size, shape, and color. The most common MPs are those smaller than 0.3 mm in diameter. These are predominantly in the form of lines and beads in all species. Fourier transform infrared (FTIR) spectroscopy was used to identify the types of polymers present. The types of polymers identified in the study were polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and ethylene vinyl acetate (EVA). The most common polymers were PE and PP, which showed hazard indices classified as “hazard” and “high risk,” respectively. The study identifies potential health risks associated with MPs, particularly in marine organisms, including apex predators such as D. labrax and filter feeders such as mussels. These findings highlight the need for effective waste management strategies, stricter regulations, and increased public awareness to reduce pollution of marine environments with plastic.

Bu çalışmada Uluabat Gölü havzasında bulunan noktasal kirletici kaynaklara ait debi değerleri ve kirlilik yükleri, Ağustos 2013-Temmuz 2014 dönemlerini kapsayan süreçte, 12 ay boyunca, 4 farklı örnekleme noktasında izlenmiş ve parametrelerin mekânsal ve zamansal değişimleri irdelenmiştir. İzlenen parametreler; askıda katı madde (AKM), kimyasal oksijen ihtiyacı (KOI), biyolojik oksijen ihtiyacı (BOI), amonyum azotu (NH4-N), nitrat azotu (NO3-N), toplam azot (TN), fosfat fosforu (PO4-P) ve toplam fosfor (TP) parametreleridir. Çalışma sonucunda, Mustafakemalpaşa Çayı’nın (MKP Çayı)ortalama debi değerinin 8.91 m3/sn ve Kocasu Çayı’nın ise 19.72 m3/sn olduğu tespit edilmiştir. Bulunan ortalama debi değerlerinin diğer noktasal kaynaklara göre yüksek olduğu gözlenmiştir. Akçalar Deresi en düşük debiye sahip noktasal kaynak olup ortalama debisi 0.03 m3/sn’dir. Göle giriş akarsuyu olan MKP Çayı’nın göle yüksek miktarda kirlilik taşıdığı tespit edilmiştir. Kirlilik yükleri değerlendirildiğinde Akçalar Deresi’nin göle en az kirletici yükü taşıdığı (TN:19.6 ton/yıl; TP:0.3 ton/yıl; KOI:74 ton/yıl; BOI:50.5 ton/yıl; AKM:41.4 ton/yıl), Uluabat pompa istasyonunun ise en çok kirletici yükü (TN:333.6 ton/yıl; TP:5.3 ton/yıl; KOI:1570 ton/yıl; BOI:662.5 ton/yıl; AKM:368.4 ton/yıl) taşıdığı tespit edilmiştir.

This study evaluated the accumulation of heavy metals (As, Cd, Cu, Hg, Pb, and Zn) in Mediterranean mussels (Mytilus galloprovincialis) collected from five coastal stations (Küçükkumla, Kurşunlu, Güzelyalı, Mudanya, and Zeytinbağı; n = 20 mussels per station; composited into one sample per site) along the southern coast of the Marmara Sea (Bursa, Türkiye), and assessed the associated potential health risks. Analyses using ICP-OES revealed spatial variations in metal concentrations among stations. Statistical analyses (p < 0.05) showed no significant differences in As levels, whereas Cd, Cu, Hg, Pb, and Zn concentrations differed significantly. Mudanya exhibited the highest levels of Zn and Hg, while Cd was particularly elevated in Mudanya and Güzelyalı. Kurşunlu showed the highest Cu concentrations, and Küçükkumla had the highest Pb levels. Human health risk assessments for the adult population (EDI, EWI, THQ, HI) were all below 1.0, indicating no appreciable non-carcinogenic risk under the assumed adult dietary exposure scenario, based on internationally recognized toxicological reference values (FAO/WHO, JECFA, and EC Regulation 1881/2006). However, relatively higher HI values in Mudanya (0.695) and Küçükkumla (0.646) suggest the need for closer monitoring. Overall, the findings demonstrate that mussels serve as effective bioindicators of coastal metal contamination in the southern Marmara Sea and underscore the importance of continuous biomonitoring to safeguard both ecosystem and public health.

Lake Uluabat is one of the most important shallow lakes in Turkey. The lake is located 15 km south of the Marmara Sea and 30 km west of the city of Bursa. The lake is very important in terms of biodiversity, but knowledge of its water quality is somewhat limited. The objective of this study was to assess water quality in Lake Uluabat and provide information for future management decisions. The temperature (T), pH, electrical conductivity (EC), dissolved oxygen (DO), alkalinity, chemical oxygen demand (COD), nitrogen species, phosphorus species, and chlorophyll-a (Chl-a) concentrations were monitored monthly at ten sampling points in the lake between August 2013 and July 2014. As a result, it was determined that the lake water has the characteristics of class 4 waters according to the Turkish Surface Water Quality Management Regulations (SWQMR). Also it was determined that Mustafakemalpaşa Brook carries significant amount of pollution loads into the lake. According to qualitative and quantitative observations, the effects of human impact and current status of the lake were determined. The physical and chemical characteristics of the lake water have changed according to human activities and nutrient loadings. According to the trophic level values and concentration values, the Lake exceeded the regulation limits.

Dünya genelinde yaşanan hızlı nüfus artışı beraberinde besin maddelerine olan gereksinimi de arttırmıştır. Bu artıştan dolayı tarım ve hayvancılık faaliyetleri de ivme kazanmıştır. Özellikle hayvancılık faaliyetlerine dayalı ürünlerin besin içeriklerinin yüksek olması bu sektörden elde edilecek ürünlerde verim ve miktar artışına yön vermiştir. Ancak artan üretim faaliyetleri bu faaliyetlerden kaynaklı atık miktarlarının artmasına ve çeşitli çevre sorunlarına neden olmuştur. Bu çalışmada Bursa’nın Karacabey ilçesinde 2019, 2020 ve 2021 yıllarında mevcut, büyükbaş (BBH), küçükbaş (KBH) ve kümes hayvanı (KH) sayıları esas alınarak, hayvansal kaynaklı atıkların gübre içerikleri belirlenmiştir. Ayrıca, oluşan gübrelerin teorik biyogaz içerikleri hesaplanmıştır. Sonuç olarak, üç yılın sonunda 126.942.000,12 m3/yıl yaş gübre oluşma potansiyeli ve 166.707.000,10 m3/yıl biyogaz potansiyelinin elde edilebileceği hesaplanmıştır. Oluşan biyogazın 3.917.616,83 GJ/yıl enerji potansiyeline sahip olduğu ve bu enerjinin de Karacabey ilçesinin önemli oranda elektrik enerji ihtiyacını karşılayabileceği tespit edilmiştir.

Heavy metal contamination of surface waters poses serious environmental and public health concerns, particularly in industrialized river basins. This study presents an integrated assessment of heavy metal pollution and associated human health risks in the Nilüfer Stream (Bursa, Türkiye) based on a five-year monitoring dataset (2020–2024). Seasonal water samples collected from 15 stations along the main stream and its tributaries were analyzed for total concentrations of As, Al, B, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Pollution levels were evaluated using the Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), and Degree of Contamination (Cd), while non-carcinogenic and carcinogenic health risks for adults and children were assessed via ingestion exposure following USEPA guidelines. Mean concentrations of Al, Fe, Mn, As, and Ni exceeded international drinking water guideline values, indicating significant contamination within the basin. All indices classified the Nilüfer Stream as severely polluted (HPI = 274.32; HEI = 49.59; Cd = 49.59), with higher values during summer and autumn due to reduced dilution. Principal component analysis revealed strong associations among Al, Fe, Mn, Ni, Cr, and Cu, suggesting a common origin likely related to cumulative anthropogenic inputs, while arsenic exhibited a distinct pattern linked to toxicological risk. Health risk assessment showed that the hazard index exceeded safe thresholds for both age groups, with children being more vulnerable. Arsenic and nickel were the main contributors to both non-carcinogenic and carcinogenic risks, with arsenic posing an unacceptable lifetime cancer risk. Overall, the results indicate severe cumulative heavy metal pollution and associated health risks, highlighting the need for continuous monitoring, effective pollution control, and integrated river basin management.