Stormwater ponds serve as best management practices to trap or remove both physical and chemical pollutants before further discharge of stormwater into receiving natural waterbodies. Stormwater ponds can therefore accumulate high levels of pollutants, including microplastics (MP) and microrubber (MR) from road runoff. It was hypothesized that biota in stormwater ponds that receive large amounts of road runoff, or are in proximity to roadways and major developments, would contain significant amounts of MP per individual, with high abundances of tire particles (TP). Fish and invertebrates were collected from five stormwater ponds and their adjacent tidal creeks in Mt. Pleasant, SC, USA. Whole organisms were digested using KOH and digested contents were filtered and analyzed by visual microscopy to identify and count MPs.

The majority (>80%) of MP recovered from biota across all sites were suspected TP. The average number of MP per individual ranged from 0.3 to 71 MP and the average number of suspected tire particles per individual ranged from 0 to 57.7 tire particles.

There were significant differences in MP per individual observed between sites and between species. A combination of factors such as availability of MPs based on surrounding land use, pond hydrodynamics, organism size, and species feeding habitat likely influenced the total MP observed among the different sites and species analyzed. These data provide preliminary examination into the fate and transport of MP and MR in stormwater ponds and an evaluation of MP and MR abundance in organisms from stormwater ponds in the coastal zone.