Factors Controlling Microplastic Concentrations and Polymer Profiles in Wastewater, Storm Water, and Surface Water

A critical literature review was performed to document current microplastic occurrence data across freshwater matrices (i.e., drinking water, groundwater, surface water, stormwater, wastewater). A total of 143 studies meeting minimum quality standards were included in the resulting microplastic occurrence database. The various extraction methods, analysis techniques, and quality assurance controls were documented. Results indicated that MP concentrations reported in wastewater varied eight orders of magnitude with generally the highest concentration reported for particles in the smallest size range. Researchers reported one to seventeen polymer types per sample with polyethylene and polypropylene the most commonly observed polymers. Utilities and practitioners should be aware of the impact of various study designs and analysis methods on observed MP concentration and polymer profiles as well as quality assurance issues in the current literature when using it for decision making.