Sarah Hobson

Sarah Hobson

Sarah Hobson

Speaker | University of Vermont

Burlington, VT |

Graduate researcher at The University of Vermont in microplastic contamination of compost (emphasis on Vermont) and microplastic impacts on soil biogeochemical cycling (emphasis on agricultural soil). Life-long composter, humanure extraordinaire, and environmental engineer in training (EIT). International background and engaged in food rescue and local mutual aid community efforts.

Session Code: E3

Track: Markets, Marketing and Uses

Session Name: Current Research: Value vs Cost, Urban Carbon Farm, Microplastics

Session Time: Wednesday, Jan 26, 4:15 – 5:45 PM

Presentation Title: An Emerging Issue? Compost Plastic Contamination and Possible Soil Health Implication

Presentation Description: Recent efforts worldwide to divert organic wastes from landfills have increased the generation of food-waste derived composts. As an important organic amendment, it is crucial that the potential role of plastic contamination in these composts is better quantified and understood. However, the diversity of environmental conditions and characteristics inherent to microplastics (MPs) throughout space and time complicate previous research findings and the applicability of observed effects. A better understanding of plastic and MP abundances in food waste-derived composts is necessary to inform further research on potential physical and ecotoxicological effects of MPs in soils. In order to address this, a MP compost contamination survey will be conducted across Vermont and potential MP effects on key soil processes will be measured at environmentally relevant levels. The initial survey will include compost from a diversity of feedstocks and processing methods. MP extraction and identification methods will be developed in this phase, as no standard methods exist to date. Potential effects of MPs on key soil processes will then be measured at environmentally relevant levels. This will be done through aerobic incubations with MP concentrations relevant to both the survey and literature values and aims to quantify potential changes in substrate-induced carbon mineralization, ammonification, and nitrification. Findings will provide applicable information for compost practitioners, agriculturalists, and policymakers regarding the presence of MP’s and their soil health implications.