Patterns and Trends in Sediment Toxicity

1
Patterns and Trends in Sediment Toxicity in the
San Francisco Estuary Brian Anderson, Bryn
Phillips, John Hunt University of California,
Davis Bruce Thompson, Sarah Lowe San Francisco
Estuary Institute Karen Taberski California
Regional Water Quality Control Board San
Francisco Bay Region R. Scott Carr USGS Corpus
Christi
2
Contaminants entering the estuary attach to
particles which may then be deposited as
sediments
Contaminants may impact benthic organisms or
higher trophic level species
3
Laboratory Toxicity Testing (UC Davis
Marine Pollution Studies Lab)
Amphipod 10-d survival test
Measures acute effects
4
Mussel embryo development
48-h exposure Sublethal endpoint
Sediment elutriate exposure
Sediment-water interface exposure
5
Toxicity test data used in a weight-of-evidence
Tests used are those recommended for evaluating
compliance with proposed statewide SQOs
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
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Napa River
Grizzly Bay
San Pablo Bay
Rivers
Horseshoe Bay
 
Yerba Buena Island
Redwood Creek
San Jose
Coyote Creek
South Bay
Some stations are consistently toxic, others
exhibit seasonal toxicity
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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)
2002
100
Stations toxic to amphipods
50
18
0
Summer
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Amphipod response vs. contaminant mixtures
100
80
r - 0.685
p lt0.0001
60
n 118
Amphipod survival
40
20
0
0.06
0.20
0.40
0.60
0.80
1.00
1.40
mERMQ
Always Toxic
Never Toxic
toxic
nontoxic
Thompson et el. 1999
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Amphipod response vs. contaminant mixtures
toxic
nontoxic
100
80
r - 0.685
p lt0.0001
60
n 118
Amphipod survival
40
20
0
0.06
0.20
0.40
0.60
0.80
1.00
1.40
mERMQ
Always Toxic
Never Toxic
Benthic impact 68 stations
Benthic impact 100 stations
Thompson et el. 1999 Thompson and Lowe 2004
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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
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Grizzly Bay Bivalve TIE w/ 25 Elutriate
Mortality ()
Phillips et al. 2003
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Grizzly Bay Sediment-Water Interface TIE w/ EDTA
Mortality ()
Phillips et al. 2003
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• Bivalve TIEs Summary
• Copper is implicated as the primary cause of
  sediment
• toxicity to bivalves in Grizzly Bay samples
  (elutriates, sediment-water interface)
• u Divalent metals cause elutriate toxicity at the
  majority of stations where elutriate TIEs have
  been conducted
• Amphipod TIE Summary Grizzly Bay (in Hunt et al.
  2005)
• Toxicity is probably not due to organic
  chemicals
• Sediment is toxic, pore water is not
• Toxicity is due to some acid-soluble compound

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North Bay Rivers
Napa River
Petaluma River
Coyote Creek
Redwood Creek
Guadalupe River
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Results of NOAA/EMAP studies 2000-2001
Toxic
Grain Size
SQGQ1
TOC
n
2.94 96.55
0.8 3.86
A. abdita
198
1.5
0.46 - 8.82
E. estuarius
48
67
A. punctulata embryo develop.
199
82
A. punctulata fertilization
199
32
Tested using 100 porewater
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Water Column Toxicity

• Toxicity of water has been assessed with mysid
  shrimp and larval fish
• Reductions in water column toxicity is apparently
  associated with reduced applications of OP
  pesticides
• Previous evidence suggests toxicity is greatest
  during storm events
• Water column toxicity is now assessed every 5
  years in summer sampling at selected Status and
  Trends stations
• This design does not address winter stormwater
  toxicity at the margins of the Estuary

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Proposed Future Work Sediment Toxicity

• Continued Status and Trends monitoring
• Application of TIEs at stations consistently
  toxic to amphipods
• Emphasize winter sampling at the mouths of key
  tributaries
• Proposed Special Studies
• Gradient studies to link sediment toxicity with
  benthic
• community impacts validation of sediment
  quality objectives
• Dose-response toxicity tests with resident and
  surrogate
• toxicity test species this work is now
  being conducted

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Proposed Future Work Water Toxicity

• Continued Status and Trends monitoring on 5 yr
  cycle
• Emphasize winter sampling at the mouths of key
  tributaries (incorporate chronic endpoints)
• Synoptic sampling with sediment toxicity special
  studies?