Summary of 10 years of sediment toxicity monitoring for the San Francisco Estuary Regional Monitoring Program

Brian Anderson, Bryn Phillips, John Hunt, Patricia Nicely, Ron Tjeerdema University of California, Davis

Bruce Thompson, Sarah Lowe, Jay Davis San Francisco Estuary Institute

Karen Taberski California Regional Water Quality Control Board – San Francisco Bay Region

Contaminants entering the estuary attach to particles which may then be deposited

as sediments

Contaminants may impact benthicorganisms or higher trophic level

species

Amphipod 10-d survival test

Laboratory Toxicity Testing(UC Davis – MarinePollution Studies Lab)

Measures acute effects

Mussel embryo development

48-h exposureSublethal endpoint

Sediment-water interface exposure

Sediment elutriate exposure

Sediment contamination

Sediment toxicity

Benthic community structure

Bioaccumulation

Results used to identify and map areas of impaired or potentially impaired beneficial uses:

Aquatic life

Human health

Wildlife

Sediment Quality Triad

Toxicity test data used in a weight-of-evidence

0%

50%

100%

0%

50%

100%

0%

50%

100%

Rivers

Grizzly BayNapa RiverSan Pablo Bay

0%

50%

100%

0%

50%

100%

South Bay

0%

50%

100%

Redwood Creek

0%

50%

100%

Yerba Buena Island

0%

50%

100%

Horseshoe Bay

0%

50%

100%Coyote Creek

San Jose

0%

50%

100%

Legend:

0%

50%

100%

Sampling Period (1993 to 2001)

Amph % Survival Biv % Norm. Dev. 

Some stations are consistently toxic, others exhibit seasonal toxicity

Change in RMP Experimental Design:

1993 –2001: Winter and Summer Sampling of Fixed Stations

2002-2003: Summer Sampling Using Probabilistic Sampling Design (7 fixed stations + 21 random stations)

Winter Summer0

50

1001993-2000

% S

tati

ons

toxi

c to

am

ph

ipod

s

36%

10%

Summer0

50

1002002

% S

tati

ons

toxi

c to

am

ph

ipod

s

18%

0

20

40

60

80

100

0.06 0.20 0.40 0.60 0.80 1.00 1.40

toxic nontoxic

Never Toxic Always Toxic

r = - 0.685p = <0.0001n = 118

Am

ph

ipod

% s

urv

ival

mERMQ

Amphipod response vs. contaminant mixtures

Thompson et el. 1999

0

20

40

60

80

100

0.06 0.20 0.40 0.60 0.80 1.00 1.40

toxic nontoxic

Never Toxic Always Toxic

r = - 0.685p = <0.0001n = 118

Am

ph

ipod

% s

urv

ival

mERMQ

Amphipod response vs. contaminant mixtures

Benthic impact68% stations

Thompson et el. 1999Thompson and Lowe in review

Benthic impact100% stations

Toxicity Identification Evaluations (TIEs)

Phase I – characterization: e.g., metals vs organics, ammonia, H2S

Phase II – identification: specific metal or organic compound(s) responsible for toxicity

Phase III – confirmation

Consider confounding factors: grain size, ammonia, pH etc.

Once identified, chemical responsible for toxicity are emphasized in later studies : Source identification and control

0102030405060708090

100

Ba

se

lin

e

Filtr

ati

on

Ae

rati

on

ED

TA

ST

S

pH

7.9

pH

8.1

pH

8.4

C1

8 C

olu

mn

C1

8 E

lua

te

Ca

tio

n C

olu

mn

Mo

rtal

ity

(%)

Grizzly Bay Bivalve TIE w/ 25% Elutriate

Phillips et al. in press

0

20

40

60

80

100

Control Controlw/EDTA

Site Sitew/EDTA

Mo

rtal

ity

(%)

Sediment-Water Interface TIE w/ EDTA

Phillips et al. in press

Bivalve TIE Summary: Grizzly Bay

Copper is implicated as the primary cause of sediment toxicity to bivalves (elutriates, sediment-water interface)

Other divalent metals may also contribute to elutriate toxicity

Amphipod TIE Summary: Grizzly Bay

Toxicity is probably not due to organic chemicals

Sediment is toxic, pore water is not

Toxicity is due to some acid-soluble compound

Napa River

Redwood Creek

Coyote Creek

North Bay Rivers

Petaluma River

Guadalupe River

Future Work

Continued Status and Trends monitoring

Application of TIEs at consistently toxic stations

Winter samples

Possible Special Studies

Winter sampling at the base of key tributary streams

Dose-response toxicity tests with resident and surrogate toxicity test species