Characterisation of microplastic contamination in sediment of England's inshore waters

Abstract

Plastic litter is an increasingly significant problem in the marine environment. Our study looks at a cost-effective method to quantify larger fractions of microplastics in marine sediments as an opportunistic addition to standard benthic infauna sampling. A subsample of microplastics (>1 mm) were enumerated and categorised from sediment samples collected as part of standard benthic habitat monitoring in twenty-two Marine Protected Areas across English inshore waters. Microplastic particles were found in 61.2% of the samples collected, with mean density per study site ranging from 0.2 in Dover to Deal MCZ to 42.7 in The Mersey Estuary Special Protection Area microplastic particles per 0.1 m². High densities of plastic were found at remote sites, as well as those closer to urban or industrialised areas. Spatial protection measures such as MPAs are not themselves a suitable tool to tackle marine plastic pollution which should be addressed upstream at source.

Keywords: Benthos; Estuaries; Grab sampling; Inshore; Marine protected areas; Microplastics; Monitoring; Sediment.