engleski

Microplastics occurence and metal accumulation in fish from the Krka River impacted by wastewaters

Introduction Contamination with microplastics (MPs) and metals is a global environmental problem, especially due to their persistence and accumulation in organisms which can cause toxic effects [1]. Anthropogenic activities cause their enhanced releases and wastewaters are one of the most important sources. Such example is found in the Krka River, which lower part is protected as the national park, but it is impacted by industrial and municipal effluents from the screw factory and the Town of Knin, respectively. Therefore, the aim was to estimate MPs presence, metal accumulation and biomarker responses in water and/or intestine of brown trout (Salmo trutta L.). Intestine was selected as a site of dietborne metal and MPs uptake. Methods Sampling was performed in spring of 2021 at the Krka River source (reference site, KRS), downstream from the industrial and municipal wastewaters (KRK) and in the national park, at the Brljan Lake (KBL). Presence of MPs in water and fish gut content (GC, digested with HNO3 and HF) was determined by stereomicroscope after membrane filtration. Element concentrations (As, Cd, Co, Cs, Cu, Fe, Mn, Se, Tl, Zn) were measured in water and fish intestine using HR ICP-MS. Analysis of biomarkers involved in oxidative stress (glutathione ; GSH, malondialdehyde ; MDA) was performed by spectrophotometer. Results MPs were observed in all water samples and digested GC, confirming its presence and ingestion in fish. Metal accumulation in fish was mostly higher at KRK and KBL compared to KRS, statistically significant for Fe, Mn, Zn, Tl, Cs, Se and As at KRK, and Fe, Mn, Co and Cs at KBL. Exceptions were Cs, Tl and Cd with higher levels at KRS, but most metals in water and fish confirmed impact of wastewaters, even at the location in national park. Biomarkers suggested possible oxidative stress in fish exposed to wastewaters and the need of enhanced antioxidant activity to cope with ecological disturbances as indicated by increased GSH in the downstream direction. Altogether, the presence of MPs and patterns of metal accumulation showed the necessity of continuous research in the sensitive karst ecosystem.

microplastics ; ICP-MS ; contamination ; water quality ; national par

nije evidentirano