Adsorption of microplastics on aquatic plants

Mikroplastika so majhni plastični delci različnih velikosti in sestave, ki se nahajajo v naravnem okolju in predstavljajo pomemben okoljski problem. V večini raziskav so se osredotočili na interakcije mikroplastike z živalmi, še posebej na njene vplive, ki jih povzroči po zaužitju. Zelo malo je znanega o interakcijah med mikroplastiko in rastlinami, čeprav rastline pogosto pridejo v kontakt z mikroplastiko v rastlinskih čistilnih napravah, mokriščih in akumulacijskih jezerih. Ker so rastline primarni proizvajalci in predstavljajo hrano za druge organizme, lahko interakcije mikroplastike z rastlinami predstavljajo vstopno točko mikroplastike v prehranjevalno verigo. Po drugi strani bi lahko te interakcije ponudile možnost uporabe fitoremediacije za odstranjevanje mikroplastike iz vodnega okolja. V magistrskem delu smo proučevali interakcije treh tipov mikroplastike iz polietilena z malo vodno lečo Lemna minor. Predhodno smo razvili metodo za razgradnjo rastlinske biomase, da smo lahko določili število adsorbiranih delcev mikroplastike na rastlinsko biomaso. Ugotovili smo, da se mikroplastika veže na korenine in liste male vodne leče. Povprečno se je na rastlinsko biomaso vezalo 4 % sferične mikroplastike, 15 % fragmentov in 13 % folij iz celotnega vnosa mikroplastike. Rezultati kažejo na pomembne interakcije med mikroplastiko in vodno rastlino, zato se uporaba fitoremediacije za stabilizacijo mikroplastike v vodnem okolju in nato njena odstranitev kaže za eno najbolj obetavnih pristopov in situ.Microplastics are small plastic particles of different sizes and shapes. They are present in a natural environment and represent an important environmental problem. Scientists are mainly focused on interactions of microplastics with animals, especially on the effects after ingestion. Less attention is paid on plants and their interactions with microplastics, although plants come into contact with microplastics in wastewater treatment plant, wetlands and accumulation lakes. Plants are primary producers and represent food for other organisms. So on one hand plants represent available pathway for microplastics to enter food webs, on the other hand, the strong interactions could be used for phytoremediation to remove microplastics from the aquatic environment. Our work focused on interactions of three different types of microplastic made from polyethylene with common duckweed (Lemna minor). In order to be able to evaluate the interactions, we previously developed a method for digestion of plant biomass. Our results indicated that duckweed is able to adsorb and accumulate microplastics by roots and leaves. On average, 4 % spherical microplastics, 15 % fragments and 13 % foils adsorb on plant biomass from the total input of microplastics. Our results indicate important interactions between microplastics and aquatic plants, so the use of phytoremediation to stabilize microplastics and their subsequent removal from the water is currently one of the most promising approaches to remove microplastics in situ