OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.
Water Quality Division
1657 Rollins Rd
Burlingame, CA 94010
T 650.652.3100
F 650.652.3142
July 19, 2022
TO:
THROUGH:
Commissioner Anson Moran, President
Commissioner Newsha Ajami, Vice President
Commissioner Sophie Maxwell
Commissioner Tim Paulson
Dennis J. Herrera, General Manager
Steven R. Ritchie, Assistant General Manager, Water Enterprise FROM: Andrew DeGraca, Water Quality Division Director
Subject: Contaminants of Emerging Concern in San Francisco Drinking Water, 2022 Draft Re port
Attached is the Draft Evaluation, Prioritization, and Recommendations for Contaminants of Emerging Concern (CEC) in SFPUC Drinking Water Report. CECs are contaminants that are being discovered in water that previously had not been detected or our understanding of their significance has changed. These contaminants are often generally referred to as CECs because the risk to human health and the environment associated may not be known. Microplastics serve as an example of such contaminants.
There are less than 100 regulated drinking water contaminants which have gone through a formal regulatory process including review of analytical detection methods, occurrence, treatment technologies and health impacts. The regulatory process is slow and meticulous. There are over 100,000 potential CECs. The list of detectable CECs in drinking water is growing due to improvements in analytical technologies. Pharmaceuticals serve as an example of such contaminants.
Public concern about individual CECs can develop very rapidly due to detection, limited health effect information and rapid communication (i.e., digital media). San Francisco's water system has an excellent source of supply yet trace detection of some CECs is likely in existing or future sources. Per- and Polyfluoroalkyl Substances (PFAS), so called “forever contaminant”, serve as an example of such a contaminant.
Due to the large number of CECs and lack of specific information, our CEC approach utilizes grouping and indicators and is more qualitative compared to regulated contaminants that have numeric water quality criteria. In 2011, the Commission endorsed our approach for grouping, screening, and prioritizing unregulated CECs to determine the need, if any, for further action
such as water quality monitoring. We propose our future work to focus on 10 groups vs the original 12 groups of contaminants as described in the report to better reflect the state of the knowledge and potential impact. The new CEC groups are:
• Waterborne Pathogens
• PFAS
• Disinfection By-products, Nitrosamines
• Disinfection By-products, Other
• Algal Toxins – Harmful Algal Blooms
• Inorganics
• Organics
• Pharmaceuticals/Endocrine Disrupting Compounds
• Microplastics and Nanoplastics
• Engineered Nanomaterials and Nanoparticles
This report was prepar ed by the Water Quality Division and review ed by experts from th e San Francisco Department of Public Health , Truss ell Tech, and Stanford University.
We presented our findings and recommendations to our Wholesale Customers on May 18 th and to th e CAC Water Subcommittee on May 24 th.
The initial draft report was completed just in tim e to shar e with th e CAC Water Subcommittee . As w e have done in the past, thes e stakeholders will be updated about th e progress of CEC investigations every 3 years.
As part of th e Commission ’s September 13 th Meeting, w e will hav e a Public Health Goal Report Hearing. At th at time , I can answer any questions you may have on the Draft CEC Report. I can also answer any questions you hav e before then at (650) 652-3102 or [email protected] . If the Commission has no comments on the Draft, it will be considered final and implemented.
Encl.: Evaluation, Prioritization Recommendations for Contaminants of Emerging Concern (CEC) in SFPUC Drinking Water: 2022 DRAFT Final Report.