Lab intercalibration completed to ensure high-quality, comparable data for Bight ’23 microplastics assessment

The Trash and Microplastics study element of the Southern California Bight 2023 Regional Monitoring Program has successfully completed a laboratory intercalibration exercise to ensure participating laboratories can generate high-quality, comparable results for quantifying microplastics contamination in sediment and shellfish.

The intercalibration exercise, completed in October after two rounds, evaluated four laboratories’ ability to extract, quantify, and characterize microplastic particles from samples with a known amount of microplastics. Results from the first intercalibration round indicated that laboratories did not meet the comparability criteria, with some laboratories having high contamination rates, a common challenge with microplastics analysis.

SCCWRP worked with each laboratory to help identify potential issues with sample processing and analysis and held an in-person training workshop to review standard operating procedures. All laboratories demonstrated proficiency during the second round of intercalibration exercises.

The Bight ’23 microplastics survey will use newly evaluated statewide methods for measuring microplastics to paint a comprehensive picture of where this pollution can be found in both sediment and shellfish across Southern California’s coastal ocean.