Study launched to evaluate collection methods for microplastics in drinking water

SCCWRP and its partners have launched a study comparing the performance of two methods for collecting drinking water samples in preparation for measuring their microplastics content – a key step toward enabling California drinking water agencies to start routinely monitoring microplastics.

The two-year study, which kicked off in October, will focus on an open-system method approved by the American Society for Testing and Materials (ASTM) and a closed-system method refined by the University of Toronto. Researchers will compare their effectiveness at eliminating external contamination when filtering thousands of liters of water, which can be necessary to collect enough microplastics particles from a drinking water sample.

The study’s goal is to standardize sample collection methods as part of California’s efforts to develop a comprehensive statewide monitoring program capable of generating high-quality, directly comparable data on the prevalence and spread of microplastics across diverse aquatic settings. Drinking water agencies in California are required to monitor microplastics for an initial four-year period under a policy approved by the State Water Resources Control Board in 2022.

Researchers are expected to develop draft standard operating procedures (SOPs) for collecting drinking water samples by early 2025.