Assessing Impairment of Tomales Baydue to Mercury

Kat Ridolfi, SFEINational Water Quality Monitoring

ConferenceApril 29, 2010

TMDL Impairment Assessment

• Mercury mining history

• Previous data

• Wildlife targets

• June 2009 monitoring results• June 2009 monitoring results

• Next steps and conclusions

San Francisco Estuary Institute

San Francisco

PACIFIC OCEAN

Tomales Bay watershed

PACIFIC OCEAN

PACIFIC OCEAN

Walker Creek watershed

Lagunitas Creek watershed

San Andreas

Fault

Gambonini Mercury Mine (Cinnabar)

Waste pileWaste pileWaste pile

ChannelChannelChannel

Walker Creek Delta

Walker Creek Delta

Walker Creek Delta

PACIFIC OCEAN

Gambonini Mercury Mine

0.2

0.3

0.4M

ean

MeH

g c

on

cen

trat

ion

(u

g/g

, wet

)EPA

Human Health Criterion (0.3 THg ug/g wet)

SF Bay TMDL Human Health Criterion

(0.2 THg ug/g wet)

0

0.1

Tomales Bay bivalves

Mea

n M

eHg

co

nce

ntr

atio

n (

ug

/g, w

et)

OEHHA 2004

0.6

0.8

1

1.2

1.4

Mea

n T

Hg

(u

g/g

, w

et)

Total Hg in Sport Fish

SF Bay TMDL target (0.2 THg ug/g wet)SF Bay TMDL target (0.2 THg ug/g wet)

0

0.2

0.4

BrownSmoothhound

Leopard Shark Bat Ray Pacific AngelShark

Jacksmelt Surfperches CaliforniaHalibut

Mea

n T

Hg

(u

g/g

, w

et)

OEHHA 2004

Surfperch spp.

Shark

0.8

1

1.2

1.4

Mea

n T

Hg

(u

g/g

, w

et)

Exceed SF Bay Human Health Criterion (0.2 THg µg/g, wet)

SF Bay TMDL target

0

0.2

0.4

0.6

BrownSmoothhound

Leopard Shark Bat Ray Pacific AngelShark

Jacksmelt

Mea

n T

Hg

(u

g/g

, w

et)

OEHHA 2004

SF Bay TMDL target (0.2 THg ug/g wet)

0.2

0.3

0.4

Mea

n T

Hg

(u

g/g

, wet

)Safe to Eat, in Moderation

SF Bay TMDL target (0.2 THg ug/g wet)

0

0.1

0.2

Jacksmelt Surfperches California Halibut

Mea

n T

Hg

(u

g/g

, wet

)

OEHHA 2004

Surfperch spp.

Who Do We Want to Protect?

Humans?

Piscivorous Wildlife?

Numeric Targets for Piscivorous Wildlife

Target THg

(µg/g, wet) 0.05 0.17

Species protected

Fish length 5-15 cm >15 cm

Belted Kingfisher Black-crowned Night-Heron

PACIFIC OCEAN

Walker Creek Delta

Previous Data: THg in Sediment (2000)

1.8 ug/g, dry

0.4 ug/g, dry

0.4 ug/g, dry

0.2 ug/g, dry

0.4 ug/g, dry

New Data: Sampling Sites

PACIFIC

New Data: Sediment THg

PACIFIC OCEAN

Fish Monitoring Methods

• Catch methods

• Composite samples

• Size classes• Size classes

• Target species

Small Fish THg (µg/g, wet)

0.05

0.075

0.1

TH

g (u

g/g

wet

)

Proposed Tomales Bay Wildlife target

(0.05 THg ug/g wet)

North South

0

0.025

0.05

BrazilBeach

EucalyptusBeach

WalkerDelta

Hamlet MacDonald N. Millerton LagunitasDelta

TH

g (u

g/g

wet

)

0.04

0.06

0.08

0.1

0.12

0.14

Proposed Tomales Bay Wildlife target

(0.05 THg ug/g wet)

Small Fish THg Seasonality

0

0.02

0.04

Jun-09 Nov-09 Spring 2010

Next Steps• Develop cost effective, easily replicable

monitoring program to assess temporal trends in:

–Sportfish Hg

– Invertebrate Hg

–Small fish Hg (seaonality)

• Regional Board writes TMDL

Conclusions

• Developed science to support Mercury TMDL

• Reviewed previous data

• Collected new data to fill data gaps• Collected new data to fill data gaps

• Small fish THg had three surprises

• Next steps–Water Board writes TMDL

– Long-term monitoring

ThanksCo-author: Carrie Austin (SF Bay Regional Water

Quality Control Board)

• Funding: San Francisco Bay Regional Water Quality Control Board

• SFEI reviewers, field, and data management staff– Aroon Melwani– Ben Greenfield

• Labs: Brooks Rand and Columbia Analytical

• Dr. Darell Slotton and Shaun Ayers (UCD)

• John Brezina• Technical Advisory

– Ben Greenfield– Dr. Don Yee– Dr. Lester McKee– Dr. Jay Davis– Dr. Letitia Grenier– Dr. Josh Collins– Rachel Allen– Amy Franz– John Ross– Sarah Lowe– Cristina Grosso

• Technical Advisory Committee– Dr. Bryce Johnson– Dr. Jacob Fleck– Tom Moore– Dr. Francis Parchaso

• California Academy of Sciences

• Ornithologists– Jules Evens (Avocet, Inc.)– Dr. John Kelly (Audubon)

Questions….

kat@sfei.org