A baseline for microplastic particle occurrence and distribution in Great Bay Estuary.

We extracted and analyzed microplastics (MP) in archived sediment cores from Great Bay Estuary (GBE) in the Gulf of Maine region of North America. Results indicated that MP are distributed in GBE sediments, 0-30 cm, at an average occurrence of 116 ± 21 particles g and that morphology varies by site and depth. Analysis by sediment depth and age class indicated that MP accumulation increased over several decades but recently (5-10 years) has likely begun to decrease.