Microlitter measurement in fish Rutilus rutilus from the Slovenian part of the Mura river basin | Meritve mikroodpadkov v ribah rdečeokah (Rutilus rutilus) v porečju reke Mure na območju Slovenije

English. Knowledge of the impacts of microlitter pollution on the freshwater environment is still less researched when compared to that of marine environments despite rivers being the main pathway for transport of microlitter pollution to the seas and oceans. To better understand the state of pollution with microplastics in Slovenian freshwater fish, we did the first study of microlitter in freshwater fish, in which 50 specimens of common roach (Rutilus rutilus) caught in the Slovenian part of the Mura river basin were examined for its presence. The gastrointestinal tract was dissected from each specimen and degraded with 10% KOH. Filtered samples were then checked for microlitter using a stereomicroscope and ATR-FTIR spectroscopy. Microlitter was separated into microplastic particles (0.3 – 5 mm) and textile fibres, which can be of synthetic or seminatural origin. Microlitter was found in 94% of specimens, with an average concentration of 5 ± 3 items/specimen. Colourful fragments and textile fibres were found. Fibres were the predominant form (96%) and indicated households as the main source of microlitter in the Mura river. A strong positive correlation between the number of microlitter and the weight of the fish was found (R2 = 0.70). In the future, simultaneous monitoring of microlitter in sediments, water, and fish would be necessary to assess whether Rutilus rutilus is an appropriate species for biomonitoring. Given the growing evidence of the negative effects of microlitter on organisms, it will be important to carry out biomonitoring in terms of assessing environmental status and conditions for human health.

Slovenian. Vplivi onesnaženja z mikroodpadki v celinskih vodah so še vedno zanemarljivo raziskani v primerjavi s tistimi v morskem okolju, čeprav so reke glavni vir onesnaževanja oceanov z mikroplastičnimi odpadki. Z namenom, da bi bolje razumeli stanje onesnaženosti z mikroodpadki v sladkovodnih ribah v Sloveniji, smo opravili prvo študijo mikroodpadkov v sladkovodnih ribah. Pregledali smo 50 vzorcev rib redečeok (Rutilus rutilus) iz slovenskega dela porečja Mure. Vsakemu osebku smo odstranili drobovje in ga razgradili v 10% KOH raztopini. Filtrirane vzorce smo nato pregledali pod stereo-mikroskopom in s pomočjo ATR-FTIR spektrometrije. Mikroodpadke smo ločili na mikroplastične delce (0,3 – 5 mm) in tekstilna vlakna, ki so lahko sintetičnega ali seminaravnega izvora. Mikroodpadke smo našli v kar 94 % vzorcev s povprečno koncentracijo 5 ± 3 delcev/vzorec. Najdeni so bili fragmenti različnih barv in tekstilna vlakna. Vlakna so močno prevladovala (96 %), kar nakazuje, da so glavni vir mikroodpadkov v reki Muri gospodinjstva. Ugotovili smo izrazito korelacijo med številom mikroodpadkov in težo rib (R2 = 0,70). V prihodnosti bi bilo smiselno sočasno spremljati mikroplastiko v sedimentih, vodi in ribah, da bi ocenili, ali je Rutilus rutilus ustrezna ribja vrsta za izvajanje biomonitoringa mikroodpadkov. Glede na naraščajoče število dokazov o negativnih učinkih mikroplastike na žive organizme bo potrebno izvajati biomonitoring tako z vidika ocenjevanja okoljskega stanja kot tudi s stališča varne hrane in s tem vpliva na zdravje ljudi.