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Abstract This research investigated the technical feasibility of transforming waste drill cuttings into lightweight aggregate. Drill cuttings produced from the North Sea oil field were dried, ball milled, formed into pellets and fired at temperatures between 1160 and 1190 °C. Physical properties of the manufactured lightweight aggregate, including particle density, water absorption and compressive strength, were determined. The drill cuttings had a typical evaporite composition containing high concentrations of chloride salts. This limits the potential for using the as-received drill cutting samples in lightweight aggregate production as the products formed show high levels of leaching. The addition of a washing pre-treatment to reduce the leaching of chloride ions was necessary. Washing also reduced the initial sintering temperature and improved lightweight aggregate properties. Sintering at 1180 °C produced lightweight aggregate with particle density of 1.29 g/cm³, water absorption of 3.6% and compressive strengths of 4.4 MPa. The research showed that lightweight aggregate manufacturing represents a resource efficient option for the reuse of waste drill cuttings and provides significant material saving and landfill diversion. Highlights • Beneficial reuse of waste drill cuttings in the manufacture of LWA is presented. • LWA with properties comparable to commercial products were produced. • A washing treatment was required to mitigate Cl− leaching from LWA. • The effect of washing on the physical properties of LWA is reported. [ABSTRACT FROM AUTHOR]

This study focused on quantifying the abundance of microplastics within the surface water of the River Thames, UK. Ten sites in eight areas were sampled within the tidal Thames, starting from Teddington and ending at Southend-on-Sea. Three litres of water was collected monthly at high tide from land-based structures from each site from May 2019 to May 2021. Samples underwent visual analysis for microplastics categorised based on type, colour and size. 1041 pieces were tested using Fourier transform spectroscopy to identify chemical composition and polymer type. 6401 pieces of MP were found during sampling with an average MP of 12.27 pieces L−1 along the river Thames. Results from this study show that microplastic abundance does not increase along the river. • Average MP along the River Thames decreased from 2019 (12.27 L−1) to 2021 (5.92 L−1). • Fibres made up 93.27 % of all MPs found within the river • The most commonly found polymers were polyvinyl chloride, polystyrene and polychloroprene. [ABSTRACT FROM AUTHOR]