San Francisco Bay California Toxics Rule Priority Pollutant Ambient Water Monitoring Report

In 2000, the USEPA published Water Quality Standards; Establishment of Numeric Objectives for Priority Toxic Pollutants for the State of California, commonly known as the California Toxics Rule (CTR), which established numeric water quality standards for 126 priority pollutants. Under the Policy for Implementation of Toxics Standards for Inland Surface Waters, Enclosed Bays, and Estuaries of California (also known as the State Implementation Policy, SIP) the San Francisco Bay Regional Water Quality Control Board (SFBRWQCB) is required to establish water quality-based effluent limitations in order to achieve priority pollutant standards.

For the purposes of this document “water quality criteria” (WQCs) will be used to refer both to the CTR established numeric criteria for 126 priority pollutants as well as to numeric objectives for 12 of these priority pollutants and tributyltin previously established in the San Francisco Bay Water Quality Control Plan (Basin Plan) and/or the National Toxics Rule. A number of these pollutants previously were or continue to be regularly monitored as part of the Regional Monitoring Program Status and Trends (RMP S&T). The priority pollutants not routinely included in RMP S&T were previously monitored in wet and dry season ambient water sampling in 2002 and 2003. Results of that effort are detailed in a previously issued :

Most of the priority pollutants were not detected in that study, or detected at concentrations below their WQC. Among the pollutants that were detected, a number of them were also found at similar concentrations in lab blanks, suggesting they might not have been present (or at least were at lower concentrations) in the ambient environment. Since over a decade had passed since that previous monitoring effort, the RMP embarked on an effort to repeat measurement of these seldom analyzed (non- S&T) contaminants, to ensure conditions have not changed appreciably to present greater risk for any of them.