Impact of the Covid-19 pandemic on microplastic abundance along the River Thames

In April 2020, the Covid-19 pandemic changed human behaviour worldwide, creating an increased demand for plastic, especially single-use plastic in the form of personal protective equipment. The pandemic also provided a unique situation for plastic pollution studies, especially microplastic studies. This study looks at the impact of the Covid-19 pandemic and three national lockdowns on microplastic abundance at five sites along the river Thames, UK, compared to pre-Covid-19 levels. This study took place from May 2019–May 2021, with 3-L water samples collected monthly from each site starting at Teddington and ending at Southend-on-Sea. A total of 4480 pieces, the majority of fibres (82.1 %), were counted using light microscopy. Lockdown 2 (November 2020) had the highest average microplastic total (27.1 L−1). A total of 691 pieces were identified via Fourier Transform Infrared Spectroscopy (FTIR). Polyvinyl chloride (36.19 %) made up the most microplastics identified. This study documents changes in microplastic abundance before, during and after the Covid-19 pandemic, an unprecedented event, as well as documenting microplastic abundance along the river Thames from 2019 to 2021. •82.1 % (3679 pieces) of microplastics were fibres.•Covid-19 status significantly impacted microplastic abundance.•Average microplastic abundance was highest during Lockdown 2 (27.1 pieces L−1).•Microplastic abundance decreased from pre Covid-19 (2019) to post Covid-19 (2021).•The most commonly identified polymers were PVC, PS and PCP.