Surf’s Up - Microplastics Are Making Waves in California
During late summer of this year, the Southern California Coastal Water Research Project Authority (SCCWRP) and the California State Water Resources Control Board (CSWRCB) have provided public presentations that have outlined their recent microplastics testing methods intercalibration study. A goal of the SCCWRP’s and CSWRCB’s work and the intercalibration study is to build scientific consensus around methods for monitoring microplastics in aquatic environments. For the study, draft standard operating procedures (SOPs) were developed for clean water, dirty water (e.g., wastewater), sediments, and fish tissue extraction with chemical characterization via methods outlined in our article, Microplastics are EVERYWHERE, but how will we measure them?, which ran in the June 2021 issue of The Standard. The study participants have finished reviewing the data for the clean water matrix and have developed a revised draft consensus procedure. More details on the results of this study will be included in a special microplastics issue on the journal Chemosphere. Early results provided by the SCCWRP Department Head focused on microscopy and the Raman and Fourier transform infrared (FTIR) characterization methods. These techniques provide both morphology information (spherical, fragment, fiber) along with microplastic particle counts for each of the four size fractions included in the study. Not surprisingly, accuracy and precision were lowest for those particles in the range of 1-20 µm. Based on the discussions in those presentations, it appears that Raman and FTIR spectroscopy characterization techniques are the favored approach, but the full report and data are yet to be publicly released. Look for a formal presentation with recommendations by Dr. Scott Coffin to the CSWRCB in September.
