PhD Candidacy Examination Public Presentation and Examination

Leah Gauthier, PhD Candidate in MMS

"The Occurrence of Microplastics in Prince Edward Island soils and their Metabolic Effect on Earthworms”

Microplastics are ubiquitous in the environment. They are considered an emerging environmental concern due to their bioaccumulation in marine organisms. Microplastics occur in relatively small amounts in soil but have already been found to impact the soil microbiome. As the widespread use of plastics continues, the concentration of microplastics in soils will only increase, leading to more severe effects, potentially impacting crop quality and yields. Within the soil microbiome, earthworms are good bioindicators for soil contamination in which the number, individual weight, and chemical make-up of earthworm populations reflect the severity of contamination. In soils inoculated with microplastics, earthworms’ reproduction, digestive systems and and oxidative stress processes were shown to be impacted. Thus, it is hypothesized earthworms could be used as a bioindicator for microplastic contamination. Soils will be sampled from agricultural land in central Prince Edward Island (PEI), Canada. Earthworms will be removed from the samples, and the occurrence of microplastics in the soil will be determined through conventional extraction methods. Earthworms will be placed in microcosms of various microplastic concentrations, their metabolomes assessed via proton NMR, and subjected to statistical analysis to determine if there are biomarkers reflective of microplastic contamination. This investigation will determine the current microplastic contamination levels in PEI soil and determine if the metabolic fingerprint of earthworms is significantly impacted by microplastic contamination in soil. These are valuable factors in improving the understanding of the current state of microplastic contamination in PEI and its impact on agricultural soils.

Date and Time: May 25th, 1:00 PM

Via Google meet.  All are welcome to attend. Please contact Barry Linkletter at GSC@upei.ca for the information to connect.