Over 350,000 chemicals and mixtures of chemicals have been registered for production and use worldwide. A portion of these may meet the definition of contaminants of emerging concern (CECs), chemicals that are unregulated or under-regulated, not commonly monitored in environmental media, and have the potential to enter the environment and cause adverse ecological or human health impacts. For most chemicals in use, major information gaps prevent scientists and regulators from assessing their potential risks. Determining which of the thousands of CECs pose the greatest threats to the San Francisco Bay ecosystem is a formidable challenge.

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) has monitored CECs since 2001. In 2006, the RMP established the Emerging Contaminants Workgroup (ECWG), which includes representatives from stakeholder groups, local scientists, and an advisory panel of expert researchers that work together to protect the health of the Bay by addressing the Workgroup’s guiding management questions.

1. Which CECs have the potential to adversely impact beneficial uses in San Francisco Bay?
2. What are the sources, pathways, loadings, and processes leading to the presence of individual CECs or groups of CECs in the Bay?
3. What are the physical, chemical, and biological processes that may affect the transport and fate of individual CECs or groups of CECs in the Bay?
4. Have levels of individual CECs or groups of CECs changed over time in the Bay or pathways? What are potential drivers contributing to change?
5. Are the concentrations of individual CECs or groups of CECs predicted to increase or decrease in the future?
6. What are the effects of management actions?

The overarching goal of the ECWG is to develop cost-effective CEC identification and monitoring strategies in support of management efforts to minimize impacts to the Bay. The RMP has developed a standardized process for planning and review of CECs activities. The ECWG plays a key oversight role in establishing the RMP’s priorities for CECs monitoring and evaluation. Under the guidance of this robust planning process, which focuses the RMP’s CECs work on the most important, management-relevant scientific information needs, the RMP has generated one of the world’s most comprehensive datasets for CECs in an aquatic ecosystem. While RMP stakeholders are the primary audience and users of RMP data and communications, the Program informs broader decision-making through outreach to state and federal agencies.

This report documents a major revision to the RMP CEC Strategy. Periodic revision of the Strategy is essential given the rapid evolution of the science surrounding CECs. The RMP CEC Strategy was first published in 2013 and later revised in 2017 as part of a continuous effort to refine approaches for supporting the management of CECs in San Francisco Bay.