Simulated marine plastics pollution weathering : a novel laboratory system for weathering plastics

McCumskay, Richard

Abstract

Over the last three years there has been a call for more environmentally relevant laboratory weathering experiments. These experiments would require well-defined reaction conditions and standardised reporting of both the rate of degradation and methods used. Several new designs have been proposed, however, no design has yet been developed that meets these requirements. This thesis critically reviews the current plastic weathering methodologies and presents a novel method that produces well-defined conditions, omitted by other works. The method presented here aims to implement irradiance of ultraviolet radiation (UVR), temperature and saltwater parameters in a standardised way, as the three most influential variables of marine plastic weathering. In doing so, the practice of reporting single irradiance values is questioned due to its shortfall when comparing studies. The performance of the proposed method was assessed by weathering five plastics for 18 days before the experiment was stopped due to the Covid-19 Pandemic. The degradation of the plastics was measured using a trio of FTIR interfaces (ATR, Diffuse and Specular). A novel introduction of saltwater to the plastic samples provides stable simulated marine conditions to replicate marine weathering. The weathering characteristics from this method were found to be similar to those reported in outdoor weathering studies, showing that the laboratory method presented here is able to simulate environmental weathering. Despite promising results, the performance of the system could still be improved. The ultraviolet irradiance spectrum produced by the weather-o-meter, failed to match solar irradiance over the UVR range from 310 nm – 350 nm, despite having an overall irradiance which matched solar levels. Given the wavelength specific nature of plastic degradation, future work should aim to report the spectrum used, alongside the total irradiance.

Citation

McCumskay, R. Simulated marine plastics pollution weathering : a novel laboratory system for weathering plastics. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4223038

• Thesis Type: Thesis
• Deposit Date: Apr 7, 2021
• Publicly Available Date: Feb 23, 2023
• Keywords: Environmental sciences
• Public URL: https://hull-repository.worktribe.com/output/4223038
• Additional Information: Department of Geography, Geology and Environment, The University of Hull
• Award Date: Feb 1, 2021