What are sources of dioxin in San Francisco Bay?
In the Bay Area, there is only preliminary data regarding the sources of dioxin and the relative contribution of these sources. There are a number of source categories nationally and in the Bay Area that are not well characterized. The following is a summary of source information provided by a 1998 San Francisco Bay Regional Water Quality Control Board (RWQCB or Regional Board) report.* Refinery effluent discharges are not thought to be a major source of dioxins and dioxin-like PCBs in the Bay. Most refineries do not have detectable levels in their discharges. For other water sources, conventional treatment is very efficient at removing dioxins since they tend to bind to sediments, and are removed during the waste treatment process. The following figure shows the Regional Board’s estimate (Survey of Storm Water Runoff for Dioxins in the San Francisco Bay Area, February 1997) of the mass contribution from industrial and municipal wastewater discharges, storm water, and direct atmospheri
