Microplastic pollution in freshwater is increasingly studied in the waterways of New York State. Detrimental to organisms, both through physical mechanisms such as false satiation and through chemical mechanisms due to contaminant adsorption and particle leaching, microplastics originate from a variety of yet-to-be-quantified sources. This ongoing study aims to support the quantification and source identification of microplastic pollution in the Hudson River through investigative studies to uncover patterns in microplasic concentrations. Over the past funding cycle, we found evidence to suggest that microplastic concentrations do change in time and that the change differs between streams with wastewater treatment plant contributions and streams without, depending on the flow conditions at the time of the sampling session. Ongoing work continues to compare results found using different sampling methods, investigate the influence of dams on plastic transport in rivers, and link fish diets with fish consumption of microplastics in Hudson River estuaries.