Mercury Bioaccumulation in Fish in a Region Affected by Historic Gold Mining: The South Yuba River, Deer Creek, and Bear River Watersheds, California, 1999 By Jason T. May1, Roger L. Hothem2, Charles N. Alpers3, and Matthew A. Law2 U.S. GEOLOGICAL SURVEY Open-File Report 00-367 Prepared in cooperation with Bureau of Land Management California State Water Resources Control Board Nevada County Resource Conservation District U.S. Department of Agriculture, Forest Service U.S. Environmental Protection Agency 6231-01 1California State University Sacramento Foundation, 6000 J Street, Sacramento, CA 95819-6129 2U.S. Geological Survey, Western Ecological Research Center, Davis Field Station, One Shields Avenue, Room 278, Kerr Hall, University of California, Davis, CA 95616-5224 3U.S. Geological Survey, 6000 J Street, Placer Hall, Sacramento, CA 95819-6129 Sacramento, California 2000 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey For additional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Water Resources Division Branch of Information Services Placer Hall Box 25286 Denver, CO 80225-0286 6000 J Street Sacramento, California 95819-6129 CONTENTS Abstract . 1 Introduction . 2 Overview of Mercury Use in Historic Gold Mining . 2 Study Background . 2 Human and Wildlife Health Concerns . 2 Purpose and Scope . 4 Acknowledgments . 5 Study Design and Methods . 5 Sample Collection and Processing . 5 Statistical Methods . 7 Laboratory Methods . 7 Trace Element Research Laboratory. 7 Frontier Geosciences Laboratory . 8 Quality Assurance and Quality Control . 8 Trace Element Research Laboratory. 8 Frontier Geosciences Laboratory . 8 Interlaboratory Comparisons for Quality Control. 9 Mercury Concentrations in Fish. 9 Reservoirs . 10 Lake Englebright. 10 Scotts Flat Reservoir . 11 Rollins Reservoir. 12 Lake Combie. 13 Camp Far West Reservoir. 14 Stream Habitats. 15 Discussion . 16 Summary and Conclusions. 17 References Cited . 17 Appendix: Sampling site numbers, station names, station numbers, and locations in the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999 . 30 FIGURES 1. Map of South Yuba River, Deer Creek, and Bear River watersheds, California, and locations of historic gold mining . 3 2. Map of fish sampling sites in the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999 . 6 3. Correlation plot of interlaboratory comparisons for mercury concentrations in fish tissue . 9 4. Mercury concentration for fish collected from Lake Englebright, California, 1999. A, In relation to total length. B, In relation to total mass . 10 5. Mercury concentration for fish collected from Scotts Flat Reservoir, California, 1999. A, In relation to total length. B, In relation to total mass . 11 6. Mercury concentration for fish collected from Rollins Reservoir, California, 1999. A, In relation to total length. B, In relation to total mass . 12 Contents i 7. Mercury concentration for fish collected from Lake Combie, California, 1999. A, In relation to total length. B, In relation to total mass . 13 8. Mercury concentration for fish collected from Camp Far West Reservoir, California, 1999. A, In relation to total length. B, In relation to total mass . 14 9. Mercury concentration for stream fish samples collected from the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999. A, In relation to total length. B, In relation to total mass . 15 10. Mercury concentration for all bass (Micropterus sp.)p samples collected from reservoirs in the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999. A, In relation to total length. B, In relation to total mass . 16 TABLES 1. Fish sampling sites in the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999 . 20 2. Summary of interlaboratory comparison data for mercury concentration in fish fillet samples from the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999 . 21 3. Data for fish collected from Lake Englebright, California, 1999, including common name, mercury concentration, moisture content of fillet tissue, gender, total length, and total mass . 22 4. Data for fish collected from Scotts Flat Reservoir, California, 1999, including common name, mercury concentration, moisture content of fillet tissue, gender, total length, and total mass . 23 5. Data for fish collected from Rollins Reservoir, California, 1999, including common name, mercury concentration, moisture content of fillet tissue, gender, total length, and total mass . 24 6. Data for fish collected from Lake Combie, California, 1999, including common name, mercury concentration, moisture content of fillet tissue, gender, total length, and total mass . 25 7. Data for fish collected from Camp Far West Reservoir, California, 1999, including common name, mercury concentration, moisture content of fillet tissue, gender, total length, and total mass . 26 8. Data for stream fish collected from the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999, including common name, mercury concentration, moisture content of fillet tissue, gender, total length, and total mass . 27 9. Range and mean values of mercury concentrations and length for selected fish species and locations within the South Yuba River, Deer Creek, and Bear River watersheds, California, 1999 . 29 ii Contents.