Geochemistry of mercury and other constituents in subsurface sediment—Analyses from 2011 and 2012 coring campaigns, Cache Creek Settling Basin, Yolo County, California

Data Series 1061
Prepared in cooperation with the California Department of Water Resources
By: , and 

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Abstract

Cache Creek Settling Basin was constructed in 1937 to trap sediment from Cache Creek before delivery to the Yolo Bypass, a flood conveyance for the Sacramento River system that is tributary to the Sacramento–San Joaquin Delta. Sediment management options being considered by stakeholders in the Cache Creek Settling Basin include sediment excavation; however, that could expose sediments containing elevated mercury concentrations from historical mercury mining in the watershed. In cooperation with the California Department of Water Resources, the U.S. Geological Survey undertook sediment coring campaigns in 2011–12 (1) to describe lateral and vertical distributions of mercury concentrations in deposits of sediment in the Cache Creek Settling Basin and (2) to improve constraint of estimates of the rate of sediment deposition in the basin.

Sediment cores were collected in the Cache Creek Settling Basin, Yolo County, California, during October 2011 at 10 locations and during August 2012 at 5 other locations. Total core depths ranged from approximately 4.6 to 13.7 meters (15 to 45 feet), with penetration to about 9.1 meters (30 feet) at most locations. Unsplit cores were logged for two geophysical parameters (gamma bulk density and magnetic susceptibility); then, selected cores were split lengthwise. One half of each core was then photographed and archived, and the other half was subsampled. Initial subsamples from the cores (20-centimeter composite samples from five predetermined depths in each profile) were analyzed for total mercury, methylmercury, total reduced sulfur, iron speciation, organic content (as the percentage of weight loss on ignition), and grain-size distribution. Detailed follow-up subsampling (3-centimeter intervals) was done at six locations along an east-west transect in the southern part of the Cache Creek Settling Basin and at one location in the northern part of the basin for analyses of total mercury; organic content; and cesium-137, which was used for dating. This report documents site characteristics; field and laboratory methods; and results of the analyses of each core section and subsample of these sediment cores, including associated quality-assurance and quality-control data.

Suggested Citation

Arias, M.R., Alpers, C.N., Marvin-DiPasquale, M.C., Fuller, C.C., Agee, J.L., Sneed, Michelle, Morita, A.Y., and Salas, A.J., 2017, Geochemistry of mercury and other constituents in subsurface sediment—Analyses from 2011 and 2012 coring campaigns, Cache Creek Settling Basin, Yolo County, California: U.S. Geological Survey Data Series 1061, 150 p., https://doi.org/10.3133/ds1061.

ISSN: 2327-638X (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • The 2011 Deep Core Drilling Campaign
  • The 2012 Deep Core Drilling Campaign
  • Coring Methods and Equipment
  • Calculation of Core Depths
  • Determination of Land-Surface Elevations at Coring Locations
  • Sediment-Core Processing
  • Laboratory Analysis
  • Coring Results
  • Graphical Core Descriptions
  • Laboratory Analysis Results
  • Summary
  • References
  • Appendixes 1–2

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Geochemistry of mercury and other constituents in subsurface sediment—Analyses from 2011 and 2012 coring campaigns, Cache Creek Settling Basin, Yolo County, California
Series title Data Series
Series number 1061
DOI 10.3133/ds1061
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) California Water Science Center
Description vi, 150 p.
Country United States
State California
County Yolo County
Other Geospatial Cache Creek Settling Basin
Online Only (Y/N) Y