CA SWRCB Issues Draft Microplastics Drinking Water Sampling and Analysis Approach

CA-SWRCB issues draft recommendations for water-purveyor sampling: DRAFT MICROPLASTICS IN DRINKING WATER POLICY HANDBOOK: https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/documents/microplastics/mcrplsts_plcy_drft.pdf to be heard at 11/17 SWRCB Meeting.

Two Phases, similar to USEPA SDWA UCMR. Each phase will be 2 years, with 6 months in-between, where Phase distinction generally has to do with target microplastic size (Phase I ... 20 um; Phase II down to 5 um). Initial Phase I orders will predominantly go to larger CA-purveyors (>er 10,000 MGD and serving >er 100,000 people).

Phase I orders for sampling anticipated "Summer of 2022"

Sampling via "ASTM D8332-20: Standard Practice for Collection of Water Samples with High, Medium, or Low Suspended Solids for Identification and Quantification of Microplastic Particles and Fibers"

"in the first phase of monitoring, a representative sample of water sources will be required to monitor, with a focus on characterizing sources which serve the greatest number of consumers. Wholesale water providers and raw water conveyance systems producing greater than 10,000 MGD and water systems serving over 100,000 people will receive the majority of monitoring orders in Phase I. The State Water Board will evaluate findings from Phase I to determine sampling locations for Phase II."

"The Policy includes a two-step iterative four-year plan for monitoring and reporting microplastics in a systematic and harmonized manner. To date, no government in the world has required monitoring for microplastics in drinking water, and the data obtained through the efforts detailed in this Policy will provide valuable insights for determining exposure to consumers through drinking water."

"Due to significant uncertainties regarding risks of microplastics through drinking water and the costs to reliably monitor microplastics, an adapted version of the UCMR will be utilized to minimize impacts to water systems, while obtaining sufficient data to estimate general occurrence and potential human exposure through drinking water"

"The Method Study determined that costs and analysis time for microplastics analysis using the standardized methodologies are higher than many unregulated and regulated contaminants. Method Study participants evaluated the potential for inexpensive, rapid surrogate monitoring methods to indicate the presence of microplastics, which may be used to determine if additional monitoring using Raman or infrared spectroscopy is appropriate. Some examples of potentially viable surrogate methods include techniques that are commonly employed in water systems such as total organic carbon or turbidity analysis, while additional methods are more novel, such as spectral flow cytometry or automated imaging microscopy using Nile red dye. At the time of writing this Policy, no surrogate methods for microplastics have been rigorously evaluated, however several candidate methods identified by Method Study participants are listed in Attachment C. Several candidate surrogate methods (i.e. total organic carbon, turbidity, total suspended solids) are commonly used, and water systems receiving monitoring orders will be required to submit data using these techniques alongside microplastics monitoring data. State Water Board staff will assess the potential capabilities for surrogate monitoring tools to indicate?the presence of microplastics using submitted data."

Draft Schedule:

• 5.4.1. Spring, 2022: Environmental Laboratory Accreditation Program will offer accreditation to qualified laboratories to monitor for microplastics in nonpotable water and drinking water.
• 5.4.2. Summer, 2022: State Water Board will issue monitoring orders in accordance with Phase One of planned monitoring.
• 5.4.3. Summer, 2024 – Winter 2025: Interim period in which State Water Board staff will assess results from Phase One and determine best approach for Phase Two.
• 5.4.4. Winter, 2024: State Water Board will issue monitoring orders in accordance with Phase Two of planned monitoring.
• 5.4.5. Winter, 2026: Completion of Phase Two of planned monitoring.