Microplastics data in UK (England and Wales) seafloor sediments from 2013 to 2021

This dataset presents the abundance of microplastics in seafloor sediments for the different Clean Seas Environment Monitoring programme (CSEMP) stations from 2013 to 2021. Additional parameters included particle size analysis (PSA) with % gravel, % sand and % silt as well as data from organic carbon and nitrogen (OCN) analysis.
Sediment samples were collected as part of CSEMP. Sediment samples were collected using a stainless steel 0.1 m2 Day Grab, rinsed before deployment with Pentane to reduce sample contamination between sites. Surficial sediment (top 2-3 cm) was collected using a solvent rinsed metal spoon and placed in a pre-rinsed glass jar with foil and cap. Samples were stored at -18oC until ready for analysis. Plastic items stability was assumed following the freezing process from direct observation. Plastic items were separated from sediments using a solution of zinc chloride (density 1.5 g.mL-1) and samples were digested for 3 days at 40oC using a mix of potassium hydroxide and sodium hypochlorite (30% KOH:NaClO v:v). Extracted particles (< 10%) were analysed using micro-Fourier Transform infrared spectroscopy (FTIR).