Sierra Nevada Mercury Impairment Project (SNIP) Charlie Alpers 1 , Julie Yee 2 , and Darell Slotton 3 1 USGS California Water Science Center, Sacramento, CA 2 USGS Western Ecological Research Center, Sacramento, CA 3 UC Davis, Davis CA DTMC Sept. 10, 2013
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Sierra Nevada Mercury Impairment Project (SNIP) · Sierra Nevada Mercury Impairment Project (SNIP) Charlie Alpers1, Julie Yee2, and Darell Slotton3 1 USGS California Water Science
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Sierra Nevada Mercury Impairment Project (SNIP)
Charlie Alpers1, Julie Yee2, and
Darell Slotton3
1 USGS California Water Science Center, Sacramento, CA 2 USGS Western Ecological Research Center, Sacramento, CA
3 UC Davis, Davis CA
DTMC
Sept. 10, 2013
Outline of Presentation
• Goals and objectives • Research team • Approach
– Compilation of available data (Hg and ancillary) – Preliminary analysis of correlations – Collection of new data (fish, water, sediment) – Analysis of correlations with full data set
Goal: Develop tool (model) to predict river fish tissue Hg above threshold values (0.2 and 0.3 mg/kg) using:
• Sediment chemistry (THg, MeHg, Hg(II)R, AVS, LOI) • Water chemistry (THg, MeHg, DOC, SO4, pH) • Gold mining and milling history
• Hardrock mines (gold-quartz vein deposits) • Hydraulic mines and dredging (placer deposits) • Estimate Hg losses from tons of ore processed, ounces of Au produced
• Watershed characteristics • (e.g. Land Use / Land Cover, % wetlands, forest, etc.)
Approach: Compile available data, collect ~30 additional samples
• Apply multi-variable linear regression approach • Look for significant relationships • Develop predictive model (if data and correlations are sufficient)
Research Team • USGS CAWSC
– Charlie Alpers, Jim Orlando, Jacob Fleck, Liz Beaulieu
• USGS NRP, Menlo Park, CA – Mark Marvin-DiPasquale, Evangelos Kakouros
• USGS WERC, Davis, CA – Julie Yee, Josh Ackerman
• USGS WIWSC – Barb Scudder Eikenberry, Dave Krabbenhoft
• UC Davis – Darell Slotton, Shaun Ayers
• Volunteers – Joanna Burgess (mine records), Scott Stephens (GIS)
• Contractor – Sierra Fund (mill records)
• Cooperator (SWRCB) – Liz Haven, Rick Humphreys
• Compiled data from multiple sources (CEDEN, NWIS,
RWQCB’s, etc.)
• Hg in water, sediment and tissue
• All surface-water sites (rivers, lakes, delta, etc.)
• More than 5,300 sites statewide with Hg data
• 775 Hg-related analytes (excluded organics)
• More than 500,000 individual records
State-wide Hg data compilation for SNIP
Available Hg Data for Sierra Nevada
• 1112 fish samples from 106 sites – 1054 individuals, 58 composites
• ~47,000 in California • Total of ~300,000 records in Western states incl. Alaska
– No information on total production or tons processed – No basis for quantitative estimation of Hg losses
• Significant Deposits Database (USGS) – Contains ~1,000 records nationwide on largest historical producers of Au, Ag, Cu, Zn, and Pb
• ~200 records in California • Total of ~800 records in Western states incl. Alaska
– Systematic information on total production (metal and ore) – Useful basis for quantitative estimation of Hg losses
• Ledgers of annual mine production (USGS and State geological surveys) – Comprehensive data starting in 1902 – Confidential records – limited access, publishable only in aggregated form – Hardrock mining records include stamp mill inventory
• Significant correlations between amount of ore processed and number of active stamps • Number of active stamps can be used to estimate historical Hg losses at each stamp mill
• Other sources (pre-1902) – Reports of the Director of the U.S. Mint (starting in 1880) – Mining & Scientific Press (weekly news summary, San Francisco, 1860’s to 1920’s) – Various libraries and historical societies
Mine site density from
MRDS (USGS database)
Gold Mine Density from MRDS
Hydraulic mines in MRDS
Source: Churchill (2000)
Modeling length-normalized Hg in fish
Parameters Model 1 Model 2 Model 3
Fish species
Fish tissue type
Hg in bed sediment NA
MeHg in bed sediment NA NA
Site elevation
Number of mines NA
Hg loss NA
Mining PCA NA NA
# parameter coeffs.
# sampling points
R-square
Includes pre-project data (1980-2010) only
Summary
• Sample collection is complete
• Most laboratory analyses are complete
• Data analysis is ongoing – Considering land cover / land use variables
– Incorporating other mining metrics
• Preliminary results indicate significant correlations among key parameters (Hg in fish tissue, fish species, fish length, Hg in sediment, mining history)
• Additional work is needed to determine whether or not a predictive model will result
Planned Reports
• Pre-project data (1980-2010)
– Data report (USGS DS) (First author – J. Orlando)
• draft fall 2013, final late 2014
– Interpretive report (USGS OFR or SIR) (J. Yee or C. Alpers)
• draft fall 2013, final summer 2014
• Project data (2011-2012)
– Data report (USGS DS) (E. Beaulieu)
• draft early 2014, final late 2014
• Combined project & pre-project data (1980-2012)
– Interpretive reports (journal) (C. Alpers and D. Slotton)