The effect of the shape and the type of microplastics on adsorption of pesticides in agricultural soil

Uvod: Mikroplastika so delci plastike, ki merijo manj kot 5 mm. Zaradi vse večje letne globalne produkcije je plastika, in posledično mikroplastika, vse bolj razširjena v okolju. V zadnjih letih so bila kmetijska tla, pod vplivom sodobnega kmetijstva, prepoznana kot pomemben vir mikroplastike. Dejstvo, da lahko mikroplastika na svojo površino adsorbira onesnaževala, kot so pesticidi, je spodbudilo raziskovanje skupnega vpliva mikroplastike in pesticidov na zdravje ljudi in okolje. Namen: Namen magistrskega dela je preučiti vpliv vrste, oblike in koncentracije mikroplastike na adsorpcijo izbranih pesticidov v kmetijskih tleh. Metode dela: Z laboratorijskim poizkusom smo določali koncentracije adsorbiranih pesticidov: acetamiprida, klorantriniliprola in flubendiamida na mikroplastiko različnih vrst: PS, PET in PE. Z mešanjem vzorcev, ki so vsebovali mešanico pesticidov, določeno mikroplastiko in kmetijsko prst, smo določili delež adsorpcije. Koncentracije pesticidov, tako v vodni fazi kot adsorbirane na delce mikroplastike, smo določili s HPLC z detektorjem DAD s predhodno ekstrakcijo na trdnem nosilcu (SPE). Statistično obdelavo podatkov smo izvedli s t-testi, s katerimi smo preverjali, ali obstajajo statistično značilne razlike med izbranimi pari vzorcev. Rezultati: S statistično obdelavo rezultatov smo dokazali, da imajo kroglice mikroplastike večjo adsorpcijsko sposobnost za izbrane pesticide kot peleti in folija, Prav tako so rezultati pokazali, da je pri preučevanju vplivov na njihovo adsorpcijo pomembna vrsta mikroplastike, saj je PET pokazal večjo adsorpcijsko sposobnost v primerjavi s PE in PS. Na adsorpcijo preučevanih pesticidov vpliva tudi koncentracija mikroplastike. Glede na rezultate je bila adsorpcija na mikroplastiko večja v primeru višje koncentracije mikroplastike v vzorcu. Razprava in zaključek: Z raziskavo smo dokazali, da se pesticidi lahko adsorbirajo na delce mikroplastike. Na njihovo adsorpcijo vplivajo vse raziskovane lastnosti mikroplastike, torej vrsta, koncentracija in oblika. Z nalogo smo prispevali k boljšemu razumevanju interakcij med dvema pomembnima onesnaževaloma, mikroplastiko in pesticidi, ter podali iztočnico za nadaljnje raziskave dodatnih vidikov vpliva mikroplastike, onesnaževal in okolijskih pogojev na adsorpcijo.Introduction: Microplastics are small plastic particles measuring less than 5 mm. Due to the increasing global annual production, plastics and consequently microplastics, are becoming increasingly widespread in the environment. In recent years, agricultural soil, with modern farming practices, has been recognized as an important source of microplastics. The important property of microplastics to adsorb pollutants, such as pesticides, onto their surface, has encouraged research into the combined impact of microplastics and pesticides on the human health and environment. Purpose: The purpose of this master\u27s thesis is to examine the influence of the type, shape, and concentration of microplastics on pesticide adsorption. Methods: Through a laboratory experiment we determined the concentrations of adsorbed pesticides: acetamiprid, chlorantriniliprole and flubendiamide on microplastics of different types: PS, PET and PE. Pesticide concentrations were determined by mixing samples containing a mixture of pesticides, microplastics and agricultural soil to define the adsorption process by employing the solid-phase extraction (SPE) and high-performance liquid chromatography followed by diode array detection. Results: With a statistical analysis of the results, we have proven that the fragments of certain shape (small beads and balls) have a higher adsorption capacity. Furthermore, our findings have shown that the type of microplastics is significant in studying its impact on adsorption. In our case, PET showed a higher adsorption capacity than PE and PS. The concentration of microplastics also affects adsorption, with the results indicating better adsorption at higher concentrations of microplastics. Discussion and conclusion: With our research we have demonstrated that pesticides can adsorb onto microplastic particles. The adsorption is influenced by all the investigated properties, including type, concentration, and shape of microplastics. With this study we have contributed towards a better understanding of the interactions between two significant pollutants, microplastics and pesticides, and provided a starting point for further research on additional aspects of the impact of microplastics, pollutants and the environment on adsorption