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

• Preliminary results – Fish tissue (Slotton) – Preliminary analysis (Alpers / Yee)

• Planned reports

Sierra Nevada Mercury Impairment Project

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

– 16 species: • Rainbow trout (626), Smallmouth bass (237), brown trout (123),

Sacramento pikeminnow (106) Sacramento sucker (105), spotted bass (81), sculpin (78), green sunfish (25), brook trout (12), largemouth bass (10), redeye bass (5), bluegill (5), yellow perch (4), California roach (4), hardhead (2), channel catfish (1)

• 24 sediment samples – 15 sites with both sediment and fish tissue

• 285 surface-water samples

Locations of pre-project sediment and fish samples

Data collected for this project

• About 400 fish from 24 sites – 4 sites sampled in both 2011 & 2012

– All individual fish – mostly fillet tissue

– Mostly rainbow trout, some brown trout

– Analyzing THg in all (10+ per site), Se in subset (3 per site)

• 28 stream-bed sediment samples – THg, MeHg, RHg(II), LOI, AVS, trace metals (< 0.063 mm)

• 28 surface-water samples – THg (F+P), MeHg (F+P), DOC, SSC, trace metals, major

cations & anions, chlorophyll-a

2011 2012

Feather R. - NF 3 2

Feather R. - MF 2 2

Feather R. - SF 2

S Yuba R, 2 3

Deer Cr 1

Bear R 2

American R - MF 2

American R - SF 2

Cosumnes R - MF 1 2

Merced R. 2

totals 10 18

Summary of SNIP

samples

by year and by watershed

Locations of SNIP sediment and fish samples

Compatible Hg data collected in 2010-12 for other projects

• Deer Creek / Stocking Flat (2010-11) – 2 sites, about 90 fish (rainbow and brown trout)

– About 15 bed sediment samples (4 sites)

– About 50 water samples (4 sites)

• South Yuba River / Humbug Creek (2012) – 2 sites, 26 fish (rainbow trout and Sacramento suckers)

– 7 sediment samples (7 sites)

– 7 water samples (7 sites)

Available data SNIP data Other USGS projects Totals

pre-2011 2011-12 2010-12

all fish 1112 400 116 1628

rainbow trout 626 375 33 1034

sediment 24 27 22 73

water 285 27 57 369

total sites 106 24 11 141

watersheds 21 10 2 23

Summary of Hg data available for correlation analysis

Transition TO Darell Slotton’s slides

Herbivores

1° Predators

Trout muscle (250 g normalized)

2° Predators

Drift Feeders

1.00

0.00

0.50

ppm Hg (dry wt)

Invertebrate Biosentinel

and Trout Mercury in

Northwestern Sierra Nevada

Watersheds (1993-1996)

Herbivores

1° Predators

Trout muscle (size- normalized, 250 mm)

2° Predators

Drift Feeders

1.00

0.00

0.50

ppm Hg (dry wt)

• Mercury exposure conditions

are variable across the

Northwestern Sierra

Gold Country.

• Strong signal of residual,

bioavailable mercury.

• Centered on historic

gold mining zone.

• Consistent across

different biosentinels.

Normalizing mercury data to consistent,

inter-comparable fish size (250 mm = app. 10”)

250 mm size-normalized Hg:

63 ng/g (=0.063 ppm)

Intensive Look at One High Mercury Area:

Yuba Project (2000, USGS / UC Davis)

Lower

Yuba

Middle

Yuba

South

Yuba

Englebright

Reservoir Lake

Spaulding

Milton

Res.

Colgate

Hwy 49

Tyler

Below

Milton

Plumbago

Bridgeport

Purdon

Missouri

Bar

Below

Washington

Below

Spaulding

Simpson Lane

Daguerra

Point

HWY 20

UCD

Englebright

Reservoir

Upstream control sites.

App. 5000’ elevation.

Above most mining and

above natural barriers.

Mid elevation sites

in historic mining zone.

App. 600-2800 ft elev.

Lower Yuba sites, downstream

of Englebright Reservoir.

Near Highway 20

Daguerra Point

diversion dam

Simpson Lane

near Marysville

Near

Highway 20

Collecting fish

Sampling trout

• Fish distributed

across size range

Young-of-year,

fingerling trout

Collecting aquatic invertebrates

Hydropsychid

Caddisflies

Perlid Stoneflies

Adult Fish Muscle Mercury (250 mm size normalized data)

Perlid Stonefly Mercury

Correlations Between Invertebrate Mercury

and Fish Mercury: Caddisfly Larvae

Perlid Stonefly nymphs vs Juvenile Trout

Juvenile Trout vs Adult Trout

CONCLUSIONS OF YUBA

PROJECT (2000-2002)

• Mercury exposure conditions are not consistent

across the Yuba project area.

• Regions of significantly elevated exposure are present

on both the South and Middle Yuba, upstream of

Englebright Reservoir to approximately 2800 feet.

• Spatial patterns of methylmercury exposure

appear to be linked to historic mining.

• Trout mercury is variable but below health guidelines.

• Biosentinels are good measures of relative exposure.

Cosumnes

American

Feather

Yuba

Bear

Merced

2011-2012 Project Sites

• 21 sites across 6 watersheds

• 5 sites in 2011 , most in 2012

• 3 sites sampled in both years

• Adult trout, range of sizes

Cosumnes

American

Feather

Yuba

Bear

N Fk

M Fk

S Fk

S Fk

M Fk

M Fk

Main Area (-Merced)

• Mostly paired sites: expected low Hg vs higher , based on mining history.

Backpack electro-fishing at wadeable sites

S Feather blw Forbestown Res.

South Wolf Creek

South Fork American River at Mosquito Ridge Rd

Electro-fishing not an option in larger rivers

Angling

Boat to access some sites

Base of Fordyce Creek at Lake Spaulding

App. 15 trout taken across available sizes

N Fk of Middle Fork American River

Middle Feather at Milsap Bar

Spanish Creek (N Feather trib.)

Silver Fork of South Fork American

Apparent planter trout at one site

(4+ months in river)

Transition FROM Darell Slotton’s slides

Data Sources on Historical Mining and Milling

• MRDS (USGS) -- (contains MAS/MILS, USBM) – Contains ~500,000 records nationwide

• ~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)

• draft early 2014, final late 2014