Automatic parametrisation of beached microplastics

Abstract

Four sandy beaches on the island of Malta were regularly sampled for Large MicroPlastic (LMP) particles having a diameter between 1mm and 5mm, at stations located at the waterline, and 10m inshore. The extracted LMPs were characterised (dimensions, surface roughness, colour) by microscopic analyses, as well as by a developed algorithm. Two-thirds of the isolated particles were smooth and the majority of these belonged to the grey -white colour category suggesting that these were preproduction pellets. Roughly six times as many particles were recorded within the inshore sampling stations as the particles recorded at the waterline stations. The automated image processing algorithm performed well when the dimension and colour parameter values it delivered were compared with those obtained by microscopic analyses.