Soil, dust, and drop inlet sediment Hg and PCB concentrations

In this component, 360 samples were collected in soil, dust, and drop inlet sediment in industrial areas of the Bay Area and analyzed of PCBs and Hg. The objective of this component was to better understand where and at what magnitude high concentrations occur in the urbanized environment. Data was collected from the cities of Richmond, Vallejo, Berkeley, Oakland, Benicia, Pittsburg, Emeryville, Concord, San Leandro, Hayward, San Jose, Sunnyvale, San Carlos, San Bruno, South San Francisco and San Francisco, plus portions of unincorporated Contra Costa County. All samples were collected in public right-of-way areas adjacent to suspected or known sources. The information developed in this component will provide a yes or no answer to the question: Where are highest concentrations of PCBs or Hg found in stormwater conveyance systems? In addition to SFEI's results, we collated all BASMAA data collected so far on soils and sediments into one data base of over 700 samples.

Subsequently, SFEI re-sampled soil, dust, and drop inlet sediments found to be elevated in PCB and or Hg. During this second phase, the samples were analyzed for PCB and Hg concentrations on three particles sizes (<25 micron, 25-75 micron, and >75 micron), plus the water used to sieve the sediment. The objective of this component is to provide data to BASMAA on the potential treatablity of materials. For example, will available sweeping technologies collect the mass stored on road surfaces or will street washing or are other source control methods be more appropriate? Once in the conveyance system, assuming no coagulation, could online treatment be feasible to trap contaminated particles and remove mass?