The Central Coast Long-term Environmental Assessment Network (CCLEAN) is a long-term monitoring program designed to help municipal agencies and resource managers protect the quality of ocean waters in the Monterey Bay area. In 2020, AMS added microplastics sampling to the CCLEAN base program sampling efforts.

In an effort to gain a better understanding of the types and quantities of microplastic particles being discharged into Monterey Bay from surrounding discharged water sources, AMS added microplastics as a contaminant to be measured under the CCLEAN program in 2020. During the wet and dry season of 2021, AMS led the effort to sample for microplastics in effluent sources and rivers discharging into Monterey Bay. Microplastics were successfully sampled in effluent at four municipal discharges and an industrial discharger, as well as in the San Lorenzo, Pajaro, and Salinas rivers in the Monterey Bay area.

Controlled volumes of effluent and river water were passed through stacked sieve systems designed to capture three different size classes of microplastic particles. Samples from each size class were then processed at Rae McNeish’s lab at CSU Bakersfield to determine microplastic particle concentrations, which are used to estimate each source’s approximate daily load of microplastic particles being discharged into Monterey Bay. Sampling occurred twice per year, during both the wet and dry seasons, to account for anticipated fluctuations in daily loads of microplastic particles with changes in public water usage and weather patterns.

AMS’s involvement in the microplastics monitoring program for CCLEAN includes coordinating with POTW managers, subcontractors, and local laboratories for sample processing, designing sampling equipment systems, protocols, and field methods, conducting sampling and field efforts, creating and managing a new microplastics database, and compiling and reporting results. There are currently no restrictions for daily loads of microplastics being discharged into Monterey Bay, but the information provided by the microplastics monitoring program will enable resource managers to make corrective actions if daily loads of microplastics in discharged water sources are found to be noteworthy or detrimental to the health of the Monterey Bay National Marine Sanctuary.

Erika Senyk

AMS Contact:
Erika Senyk is a Staff Scientist for AMS who studies water quality with a special focus on microplastics and their impact in marine and freshwater environments. Erika coordinates and performs sampling efforts for the Central Coast Long-term Environmental Assessment Network (CCLEAN) monitoring program and other water quality projects in the Monterey Bay region.