MI SB0504

Requires the Department of Environment, Great Lakes, and Energy to establish a microplastics monitoring program for public water supplies from July 1, 2027 through July 1, 2030, with quarterly testing of drinking water sources

Mandates testing of various water sources including Great Lakes shoreline surface water, major tributaries, inland lakes, groundwater near agricultural operations, and groundwater within 1 mile of landfills

Defines microplastics as solid plastic materials measuring less than 5 millimeters in size that may contain chemical additives, excluding naturally occurring polymers

Requires the department to submit a report to the legislature by July 1, 2031 summarizing findings on microplastic quantities, shapes, polymer types, potential sources, and toxicity limits based on peer-reviewed research

Report must include recommendations for continued monitoring, preliminary risk assessment, and public protection measures regarding microplastics in drinking water