Microplastics (MPs), plastic particles ranging from 1 micrometer (µm) to 5 millimeters (mm), are considered contaminants of emerging concern (CEC) and are ubiquitous in the environment. MPs occur in a variety of sizes, shapes and polymer types and have been detected in multiple freshwater matrices, including surface water, groundwater, and drinking water. Development of standardized analytical methods for freshwater matrices and information on the occurrence and characterization of MPs in groundwater systems are ongoing.
In 2025, the U.S. Geological Survey (USGS) Central Midwest Water Science Center collected samples for MP analysis near the Independence, Missouri and at McBaine Bottoms, near Columbia, Missouri. Data were collected near Independence from the alluvial aquifer and from a groundwater collection system that receives water from several municipal supply wells prior to drinking water treatment (composite site). Sampling included 26 groundwater monitoring well samples, 1 composite site sample, and 6 quality assurance and quality control (QA/QC) samples. Data were collected from the alluvial aquifer and outflow canal at McBaine Bottoms, near Columbia, Missouri. Sampling included 11 groundwater monitoring well samples, 3 outflow canal samples, and 4 QA/QC samples. Particle identification and characterization were provided by the Northern Illinois University (NIU) Microplastic Laboratory.
The datasets include particle-level measurements and identifications for MPs and non-microplastic particles provided by the NIU Microplastic Laboratory, as well as summarization of MP data derived from the particle data by particle count, size range, polymer type, sample type, and sampling location. MPs were detected in all analyzed samples.
