Exploring Macro-, Micro- and Nanoplastics in the Terrestrial Environment and Uptake by Horticultural Crops

Plastic pollution is recognised as a growing environmental concern, sparking studies into the fate of plastics in the environment and its degradation to micro- and nanoplastics. To date, research has focused on aquatic environments, whereas studies on the type, distribution, transformation and fate of plastics in the terrestrial environment and the implications for plants are currently in their infancy. Agricultural practices use plastics to improve crop quality and yield, but at the consequence of directly introducing plastics into the soil. This plastic has the potential to alter soil properties and influence growing crops. Data surrounding the impacts and internalisation of plastics by plants was critically evaluated, where a variety of plant stress responses were observed for different plastic types and particle sizes, emphasising the need to track the uptake and distribution of nanoplastics in plant tissue. This uptake has yet to be determined as tracking plastics on the nano scale represents a huge analytical challenge, due to their size, and difficulty detecting carbon-based plastics against a background of carbon-based biological and soil structures. As such, it is the least investigated size of plastic, but could potentially be the most hazardous. This research seeks to examine the presence of plastics in the terrestrial environment and investigate if plastics are able to enter the human food chain through uptake by horticultural crops. This project utilises recent advantages of radiolabelled isotopes for the synthesis of model plastic particles, that can be applied during crop cultivation in environmentally relevant concentrations. This can be measured using highly sensitive instrumentation, including liquid scintillation counting and autoradiography. It is hypothesised that accumulation will occur in the root system, with translocation to aerial parts of a plant. This may be detrimental to plant growth and lead to trophic transfer through the food chain to humans and other animals