In a press release published on June 16, 2020, the State Water Resource Control Board for the U.S. state of California informed that it has officially adopted its definition of “microplastics in drinking water,” first proposed in March 2020 (FPF reported).

Thus, “’microplastics in drinking water’ are defined as solid polymeric materials to which chemical additives or other substances may have been added, which are particles which have at least three dimensions that are greater than 1 nm and less than 5,000 micrometers (µm). Polymers that are derived in nature that have not been chemically modified (other than by hydrolysis) are excluded.”

The authority lauds the publication as “a critical first step to further the understanding of microplastics in our drinking water and the environment” and explains that it is part of “an ambitious international effort to standardize methods for monitoring microplastics in drinking water, surface water, sediment and fish tissue.” The adopted definition will be implemented in a “long-term approach” to monitor microplastics in water and “study . . . implications for public health and safety.”

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California State Water Resources Control Board (June 16, 2020). “State Water Board addresses microplastics in drinking water to encourage public water system awareness.(pdf)


California State Water Resources Control Board (June 3, 2020). “Proposed definition of ‘microplastics in drinking water.’(pdf)