The Biochemical and Exposure Science Group (BESG) provides the measurement science, standards, technology, and data required to support environmental and human health science. The BESG develops analytical and bioanalytical methods for the determination of trace chemical species, and for the characterization of microplastic pollution, that impact human health and the environment. The group applies these research and measurement capabilities to the certification of Standard Reference Materials®, and disseminates reference data for NIST and its stakeholders. The group provides advice and measurement services to other government agencies (federal, state, and local), scientific organizations, and U.S. industry, and interacts with international standards organizations and National Metrology Institutes to establish comparability of measurement capabilities. The Biochemical and Exposure Science Group maintains analytical facilities at the Hollings Marine Laboratory in Charleston, South Carolina, and at the Hawaii Pacific University Center for Marine Debris Research in Waimanalo, Hawaii.