Geochemistry of sediment and organic matter in drainages burned by the Altas and Nuns wildfires in October 2017 and of nearshore seabed sediment in north San Francisco Bay from March to April 2018

Fine-grained sediment was collected from the banks of Napa River, Sonoma Creek, and tributaries in March 2018 and from shallow nearshore areas of the northern reach of San Francisco Bay in April 2018. Bulk sediment was dated using activities of short-lived cosmogenic radionuclides (beryllium-7, cesium-137, and lead-210). Contents of potentially toxic metals and source-rock-indicative elements, including rare earth elements, were quantified in the fine fraction of sediment (particles less than 0.063 mm diameter). Ratios of stable carbon-13/carbon-12 isotopes and total carbon to total nitrogen were determined in sedimentary organic matter.