Microplastic entrainment in surface river algae: a pilot study investigating microplastic concentration during river algae removal

This pilot project utilised a novel boat design to skim and remove algae from river water and evaluated the entrainment of microplastics in surface water algae. The removed algae were estimated to contain a concentration of 55.33 microplastics per kg of algae. The microplastic concentration, normalised to the volume of water passed through the skimmer, was calculated at 1.8 microplastics per cubic metre of water. A sample of river water adjacent to the algae was also analysed as a non-direct comparison to the concentration of microplastics in the algae. Open river water adjacent to algae was calculated to have a microplastic concentration of 0.10 microplastics per cubic metre of water. These preliminary results suggest that by removing river algae, you also remove a significant amount of microplastics from freshwater systems. This novel approach can be seen as an advantage ecologically, as the main objective is to remove potentially harmful algae blooms, where the by-product of this methodology also removes microplastics from the environment. The research represents one of the first quantitative assessments of microplastics entrained in river algae collected by a skimmer. This research could be further validated and incorporated into existing reporting framework and even potentially citizen/community science protocols.