@masterthesis{Gogoi, type = {Bachelor Thesis}, author = {Gogoi, Nayan jyoti}, title = {Combined effects of microplastics and heavy metals: implications for soil microbial ecology}, school = {Hochschule Rhein-Waal}, abstract = {There is substantial evidence that microplastic pollution and heavy metal contamination pose a significant threat to the health of soils and the functioning of ecosystems. However, little is known about the interactions between heavy metals and microplastics, as well as possible biological effects when the two are combined. It is possible that MPs and heavy metals can interact in soil, causing changes in their environmental behaviour, bioavailability, and potentially toxic properties, further posing ecological risks. Therefore, the objective of this study was to evaluate the individual and combined impacts of microplastics and heavy metals on soil chemical properties, microbial biomass, microbial activity, and microbial communities in soil treated with varying concentrations of these pollutants. In an incubation experiment, soil was amended with low-density polyethylene (LDPE) and a mixture of heavy metals (Zn, Cu, and Ni) in two concentrations (Low and High). Seven treatments (Control; MP-L; MP-H; HM-L; HM-H; MP+HM-L and MP+HM-H) were analysed in seven replications. The rate of microbial respiration was determined during incubation. Following incubation, soil pH, microbial biomass carbon (C), nitrogen (N), soil fluorescein diacetate hydrolytic activity, and the abundance of archaea, bacteria, and fungi were measured as well as the effects on inorganic nitrogen (NO3-, NH4+) were determined. It was found that no significant difference existed between the control treatment and LDPE treatment in terms of soil pH, FDAse activity, microbial biomass, microbial respiration, inorganic nitrogen, and abundance of archaea, bacteria, or fungi, regardless of the concentration of LDPE (0.6\%, 1.2\%). Heavy metal treatment did, however, result in a significant decrease in soil pH, NO3, and microbial respiration particularly at high concentrations (2.68 mg kg-1), compared with treatments with LDPE and a control, suggesting that HMs suppressed microbial activity. Additionally, HMs also reduced MBN and MBC, indicating their negative effect on microbial biomass. As a result of the combination of microplastics and heavy metals, microbial biomass, and microbial respiration decreased significantly when compared to either the control treatments or the microplastics alone treatment. Additionally, the combined treatment reduces NO3- and soil pH significantly compared to the control and sole microplastic treatment There was no significant effect observed in any treatment on the abundance of archaea or fungi, indicating that the presence of MP and/or HMs had no impact on their abundance. However, the MP+HM treatment resulted in a reduction in the number of bacteria. Using a two-factor statistical analysis, the effect of two concentrations (low and high) of microplastics and/or heavy metals on these soil parameters was further evaluated. According to these results, the concentrations of added microplastics and/or heavy metals (low and high) had no significant effect (p > 0.05) on any soil parameter except for soil pH (p < 0.05). Overall, the results indicate that the presence of heavy metals, either alone or combined with microplastics, had a detrimental effect on soil ecosystem. However, this study was limited to examining the short-term effects of these pollutants on soil microorganisms and their functioning. Additional research will be necessary to determine the long-term effects of these pollutants.}, language = {en} } @masterthesis{Rohlfing, type = {Bachelor Thesis}, author = {Rohlfing, Pauline}, title = {Einfluss von Benzalkoniumchlorid auf die Selektion von Bakteriengemeinschaften und die Verbreitung von Resistenzgenen in mit Mikroplastik angereichertem Boden}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1383-opus4-18573}, school = {Hochschule Rhein-Waal}, pages = {119}, abstract = {Die zunehmende Anreicherung anthropogener Mikroverunreinigungen in der Umwelt hat in j{\"u}ngster Zeit verst{\"a}rkte wissenschaftliche Aufmerksamkeit erhalten. Der steigende Eintrag von Mikroplastik in die Umwelt kombiniert mit der Ausbreitung von Resistenzgenen erfordert eine eingehende Analyse ihrer m{\"o}glichen Interaktionen und Auswirkungen auf die {\"O}kosysteme. In dieser Studie stand die Interaktion zwischen Mikroplastik, speziell HDPE, einem nicht biologisch abbaubaren Polymer, und PHBH, eine biologisch abbaubare Alternative, in Kombination mit Benzalkoniumchlorid im Fokus. Ziel war es, deren Einfluss auf die Gemeinschaftsstruktur von Bodenmikroorganismen und die Pr{\"a}valenz von Antibiotikaresistenzgenen zu untersuchen. Unter Verwendung eines Mikrokosmos- Designs wurden organisch bewirtschaftete Bodenproben mit den vorgenannten Substanzen {\"u}ber drei und sechs Wochen inkubiert. Im Anschluss wurden die Biofilme auf den Mikropartikeln mittels qPCR und ddPCR analysiert, wobei die Abundanz von Bakterien, Pilzen und dem Klasse-1-Integron-Gen untersucht wurde. Die Ergebnisse k{\"o}nnen nicht best{\"a}tigen, dass Benzalkoniumchlorid die Verbreitung von Resistenzgenen oder mikrobielle Gemeinschaftsstrukturen beeinflusst. Im Gegensatz dazu wirkte PHBH als signifikanter Modulator, der die Vielfalt der Pilz- und Bakterientaxa im Biofilm verringerte, jedoch die Gesamtabundanz erh{\"o}hte. Vor dem Hintergrund dieser Befunde werden die potenziellen {\"o}kologischen Implikationen der Mikroplastikverschmutzung deutlich. Es betont die Notwendigkeit vertiefter Forschungen, um die komplexen Wechselwirkungen zwischen Mikroplastik und anderen anthropogenen Kontaminanten in terrestrischen {\"O}kosystemen zu verstehen.}, language = {de} }