2016 Updated ambient concentrations of toxic chemicals in San Francisco Bay area sediments

 The purpose of this memo is to communicate the most recent results for the ambient concentrations of mercury, Total PAHs and Total PCBs in San Francisco Bay area sediments. 

Regulation of dredging and dredged material disposal or reuse under the San Francisco Bay Long Term Management Strategy for Dredging (LTMS) involves, in part, evaluation of sediment chemistry characteristics. For dredged material in California, for most chemicals, there are no numeric sediment quality standards or objectives that define chemical suitability for disposal or reuse at particular placement sites.1 Consequently, Bay dredged sediments are compared to various published screening values and other guidelines, to reference site chemistry, and where available and appropriate, to ambient sediment contaminant concentrations for the Bay as a whole. Therefore, starting in 2011, the LTMS agencies have asked SFEI to calculate the ambient concentrations for a small subset of sediment contaminants that are either subject to TMDL limits for in-Bay dredged material disposal or are relevant for bioaccumulation testing for dredging (DMMO, n.d.).