Microplastic (MP) pollution is a significant environmental issue, particularly in coastal and estuarine environments. Despite widespread reports of MP occurrence globally, there is high variability in MP estimates and limited understanding of their distribution patterns within estuaries and intertidal zones. MPs can enter estuaries from freshwater and marine sources, being deposited at different tidal phases, leading to non-uniform distribution. Consequently, MP estimates can vary significantly depending on sampling location with these dynamic environments. Understanding this variability is essential for developing effective MP sampling methods and robust study designs in estuaries.
This study investigates the variability in MP abundance both within and between estuaries. Sediment samples were collected from three estuaries with differing sizes, land uses, and sediment types. At a single site within each estuary, sediments were collected from five randomly selected locations, each location sampled in triplicate. The findings will inform the optimum number of replicates needed for reliable MP assessments, guiding the creation of more effective sampling protocols.