Dissertation
ACCUMULATION AND EFFECTS OF MICRO- AND NANOPLASTIC PARTICLES IN TERRESTRIAL ECOSYSTEMS
Washington State University
Doctor of Philosophy (PhD), Washington State University
07/2024
DOI:
https://doi.org/10.7273/000006905
Abstract
Micro- and nanopplastic particles, because of their widespread utilization, are ubiquitous in the environment, and consequently can have significant impacts on ecosystems. The accumulation of microplastics in agricultural soil can potentially negatively impact soil health and plant growth. The overall goal of this dissertation is to assess the accumulation of micro- and nanoplastics in an agricultural soil, and the interaction of these micro- and nanoplas- tics with soil organisms such as earthworms and plants. In a study involving interactions of microplastics with earthworms (Lumbricus terrestris), we found that that the plastics particles were ingested by earthworms and incorporated into the cast. Both, biodegradable polybutylene adipate co-terephthalate (PBAT) and conventional polyethylene particles were ingested by earthworms, but only PBAT underwent degradation during the passage through the earthworms’ intestines. The microplastics did not cause significant changes of the mi- crobial populations in the earthworms’ guts, casts, and soil. Findings from the research withbiosolids-amended soil demonstrated that long-term application of biosolids to agricultural soil led to microplastic accumulation in the soil, but also showed that atmospheric deposi- tion of microplastics is a substantial input to microplastics accumulation. The study with nanoplastics uptake in plants revealed the accumulation of nanoplastics around root cap cells, but showing little evidence of uptake inside plant roots beyond the Casparian strip. As biosolids application and atmospheric deposition lead to micro- and nanoplastics accu- mulation in soil, the persistence of micro- and nanoplastics could lead to impacts on soil organisms and plant growth. Measuring and quantifying micro- and nanoplastics in soils of- fers insights into plastic accumulation, but only understanding the interactions of the plastic particles with soil organisms and plants provides additional information about their potential impacts. Overall, the results of this dissertation highlight that micro- and nanoplastics can accumulate in agricultural soil, and that these particles can potentially impact soil health and plant growth.
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Details
- Title
- ACCUMULATION AND EFFECTS OF MICRO- AND NANOPLASTIC PARTICLES IN TERRESTRIAL ECOSYSTEMS
- Creators
- Kaushik Adhikari
- Contributors
- Markus Flury (Chair)Karen A. Sanguinet (Committee Member)Indranil Chowdhury (Committee Member)Carolyn I. Pearce (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Crop and Soil Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 194
- Identifiers
- 99901152437801842
- Language
- English
- Resource Type
- Dissertation