Why is mercury in EBMUD wastewater an issue?

Mercury is one of the 12 toxic pollutants identified by the U.S. EPA that is impairing Central San Francisco Bay, and is listed in Section 303 (d) list of the Clean Water Act. Mercury bioaccumulates and persists in the environment. Currently, fish consumption advisories are issued in 41 States. The San Francisco Bay is included on the fish consumption advisory list.

Studies have shown that approximately one third of the mercury discharged to EBMUD's wastewater treatment plant is from dental practices and that mercury cannot be removed through the wastewater treatment process. The environmental and public health risks associated with mercury contamination have spurred the Federal EPA to issue the Dental Effluent Guidelines in 2017 and codified in 40 CFR 411