Interakcije med mikroplastiko iz avtomobilskih pnevmatik in vodno rastlino

Turk, Katja (author), Kalčikova, Gabriela (mentor)

Sodobnega življenja si brez avtomobilov ne predstavljamo več, njihovo število pa iz leta v leto narašča. Za razliko od emisij izpušnih plinov iz motorjev z notranjim izgorevanjem se le redko zavedamo onesnaževanja z delci, ki nastajajo ob stiku pnevmatike s cestiščem. Pnevmatike se med vožnjo obrabljajo, abrazija pa vodi do nastanka mikroplastike, o kateri vemo zelo malo. Ko mikroplastika zaide v okolje je podvržena številnim dejavnikom, ki vplivajo na njene lastnosti. Poleg znanja o časovno odvisnih spremembah same mikroplastike, pa je močno okrnjeno tudi razumevanje vplivov na organizme v ekosistemih. V magistrskem delu smo pokazali, da ima mikroplastika, ki je različno dolgo v okolju, različen vpliv na plavajočo vodno rastlino Lemna minor. V 9-dnevnem eksperimentu z mikroplastiko iz avtomobilskih pnevmatik, ki je bila i) takoj dodana (surova), ii) hidratirana 24 ur in iii) starana 14 dni v simuliranih okoljskih pogojih, smo spremljali adsorpcijo delcev na rastlino ter vpliv na specifično hitrost rasti in rast korenin. Preko koncentracije klorofila a in b ter aktivnosti elektronskega transportnega sistema smo ovrednotili vpliv na proces fotosinteze, merili pa smo tudi morebitni vpliv na vsebnost energetsko bogatih molekul (proteini in ogljikovi hidrati). V primeru surove in hidratirane mikroplastike so bili vplivi na rastlino posledica fizičnega oviranja rasti in mehanskih poškodb, medtem ko so imeli v primeru starane mikroplastike ključno vlogo mikroorganizmi na njeni površini. Mikroplastika je delovala kot vektor biološkega onesnaženja, s čimer smo v sistem vnesli alge, ki so se v prisotnosti obilne količine hranil močno razrasle. Kot posledica kompetitivnosti za hranila je bila inhibicija specifične hitrosti rasti in rasti korenin Lemna minor prav v primeru starane mikroplastike bolj izrazita v primerjavi s surovo in hidratirano mikroplastiko. Pri starani mikroplastiki pa smo preko zmanjšane vsebnosti klorofila in ogljikovih hidratov v rastlini opazili tudi vpliv na fotosintezo, česar ni bilo zaznati pri surovi in hidratirani mikroplastiki.

• Language: Slovenian
• Keywords: biofilm, mala vodna leča, mikroplastika, staranje, strupenost, vodni makrofiti
• Work type: Master's thesis/paper
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-161255
• Publication date in RUL: 09.09.2024

Secondary language

• Language: English
• Title: The interactions between microplastics from car tires and an aquatic plant

Abstract

Modern life is unimaginable without cars, and their number continues to rise each year. Unlike emissions from internal combustion engines, we are rarely aware of the pollution caused by particles generated from the contact between tires and the road surface. Due to abrasion, microplastics are generated but the knowledge about them is limitedOnce microplastics enter the environment, they are subjected to numerous factors that affect their properties. In addition to the knowledge gaps regarding the time-dependent changes in the microplastics themselves, there is also a significant lack of understanding of their impacts on organisms within ecosystems. In the master’s thesis, we demonstrated that microplastics with different environmental residence times have varying effects on the floating aquatic plant Lemna minor. In a 9-day experiment using microplastic from car tires, which was i) added immediately (untreated), ii) hydrated for 24 hours, and iii) aged under environmentally relevant conditions for 14 days, we monitored particle adhesion to the plant and their impact on specific growth and root development. By measuring chlorophyll concentrations and the activity of the electron transport system, we assessed their influence on the photosynthesis process. Additionally, we evaluated their potential impact on the content of energy-rich molecules (proteins and carbohydrates). Untreated and hydrated microplastics obstructed growth and caused mechanical damage to the plant, whereas aged microplastics were significantly influenced by microorganisms on their surface. As vectors of biological contamination, aged microplastics introduced algae, which rapidly developed in the nutrient-rich environment. Competition among species led to pronounced inhibition of specific growth and root development in Lemna minor exposed to aged microplastics compared to untreated and hydrated ones. Furthermore, aged microplastics exhibited a noticeable impact on photosynthesis by reducing chlorophyll and carbohydrate content in the plant, a phenomenon not observed with untreated and hydrated microplastics.

• Keywords: aquatic macrophytes, aging, biofilm, duckweed, microplastics, toxicity