gsi can affect the bioavailability of sediment-associated ... · gsi can affect the bioavailability...

Marc S. Greenberg and G. Allen Burton, Jr.

[email protected]

[email protected]

GSI Can Affect the Bioavailability of Sediment-Associated Contaminants to

Benthic Invertebrates

Ø GW-SW interactions in relation to sediment toxicity important in ecological risk assessment

Ø GSI issues exist at numerous contaminated sites:

§75% all RCRA/Superfund w/in 1/2 mile of surface water

§51% NPL sites with surface water contaminated (most via groundwater transport)

§observed at many sites we have studied

Sediment Toxicity Assessment and GW-SW Interactions

Integrated In Situ Assessment Design

Nyanza - Sudbury River System

UR-002

MP-003-01

MP-03A-03

SR-015

SR-004

RW-005RW-008

from USGS WRIR 00-4108

Hydrological Measurements - Sudbury River - Nyanza Study

Site Hydrological Conditionsa

∆h (cm) Range

VHG (cm/cm) Range

UR-002 Upwelling 0.2 – 0.9 0.004 – 0.060

MP-03A-03 Upwelling 0.2 – 10.3 0.013 – 0.137

MP-003-01 b Mixed Up/Down -0.2 – 9.70 -0.006 – 0.129

SR-015 Upwelling 0.3 – 0.7 0.007 – 0.013

SR-004 Upwelling 0.4 – 7.0 0.011 - 0.093

RW-008 Upwelling 0.4 – 3.8 0.011 – 0.051

RW-005 Upwelling 0.5 – 1.7 0.009 – 0.053

a Determined from manometer readings of two nested mini-piezometers (20, 40, 60 and 80 cm depths)bDeep water site

Chemistry - Nyanza Study

Ø Metals (incl. Ag, As, Cd, Cu, Hg, Ni, Pb, Zn) exceeded WQC in groundwater at all 7 sites and SQGs in sediments at 6 sites

Ø VOCs exceeded criteria in the groundwater at 3 sites and in the sediments at 4 sites

Ø Most exceedances in the Mill Pond and Raceway sites

Ø Contaminants detected in samples from chamber waters reflected groundwater and sediments

In Situ Exposure Nyanza Study

0

20

40

60

80

100

*

*

*

* * *

0

20

40

60

80

100

*

* * * * * *

*

Lab

Contro

ls

UR-002

MP-0

3A-03

MP-0

03-0

1

SR-015

SR-004

RW-0

08

RW-0

05

Mea

n %

Sur

viva

lM

ean

% S

urvi

val

WC

AS

48-h Exposure: Ceriodaphnia dubia

96-h Exposure: Hyalella azteca

SITE 5

SITE 18

SITE 23

Eastland Woolen MillCorinna, ME

Total chlorobenzene(vapor diffusion)

<1000 ppb/v1000 -> 10,00010,000 -> 100,000>100,000

Piezometer NestSite 5

-0.6-0.4

-0.20.0

0.2

0.4

A B C

∆h

(cm

) 20 cm40 cm60 cm80 cm

Site 18

-0.6-0.4-0.20.00.20.40.6

A B C

30 cm50 cm70 cm

Piezometer Nest

-0.6-0.5-0.4-0.3-0.2-0.10.0

A B C

10 cm20 cm30 cm40 cm

Site 23

∆h

(cm

)

0.0

0.1

0.2

0.3

0.40.5

A B C

Pristine

20 cm30 cm40 cm

Maine 1999: Hydraulic Heads

(Greenberg, M.S. et al. Environ. Toxicol. Chem. 21(2):289-297, 2002)

Mini-Piezometer Depth (cm)

Tota

lCB

nz(µ

g/L)

Site 5

0100020003000400050006000

20 40 10 30 50 16 36 56 76

56 µg/kg

Tota

lCB

nz(µ

g/L)

0

2000

4000

6000

8000

28 48 28 48 68 30 50

Site 18 Nest ANest BNest C

44 µg/kg

Tota

lCB

nz(µ

g/L)

0100002000030000400005000060000

20 20 40 10 30

Plumeobserved

Site 2321 µg/kg

Total Chlorobenzenes in Pore Water


Total Chlorinated Benzene Exposure Levels Within In Situ Chambers

0

50

100

150

200

05 18 23

Site

Tota

l CB

z (µ

g/L) Water

SurficialSediment

a a a ac

b b


* Significantly different from field reference site, Pristine (p < 0.05)

Water

SurficialSediment

Mea

n S

urv

ival

(%

)

0

20

40

60

80

100

Lab 5 18 23 Pristine

Site

* *

Hyalella azteca

0

20

40

60

80

100

Lab 5 18 23 Pristine

Site

*

*

*

Chironomus tentans

In Situ ExposureMaine Chlorobenzene Study

Ceriodaphnia dubia

0

20

40

60

80

100

Lab 5 18 23 PristineSite

Mea

n S

urv

ival

(%

)

* *


Bod

y R

esid

ue (µ

mol

/kg

lipid

)

A B MonoCBnz1,2-DiCBnz

1,3-DiCBnz1,4-DiCBnz

1,2,3-TriCBnz1,2,4-TriCBnz

0

50

100

150

200

250

300

A B A B A BSite 5

PristineSite 23

Site 18

A = Water ColumnB = Surficial Sediments

96-h In Situ BioaccumulationL. variegatus, Maine Chlorobenzene Study


Conclusions: Field Studies

l Mini-piezometer data provide a unique in situcharacterization approach--must document GW-SW conditions

l Data from mini-piezometers improved interpretation of exposure-effects relationships

l Downwelling was shown to reduce exposure in one system

Conclusions: Field Studies

l Upwelling conditions were shown to increase exposure and effects when sediments and groundwater were contaminated

l Integrated approaches are essential in a holistic assessment of sediment toxicity

Bioaccumulation Model

Ø Develop a bioaccumulation model that accurately predicts tissue concentrations for benthic species exposed to contaminated sediments

Ø Evaluate model by comparing predictions to in situ bioaccumulation at sites containing contaminated sediments

Objectives

Methods

Ø Laboratory:n Model compounds: FLU and TF

n Toxicokinetics tests (sediment bioaccumulation; waterborne kinetics)

n Sediment desorption kinetics (Tenax®-TA beads)

Ø Model development:n Parameterized with laboratory and literature data

n Used kinetic rate constants for pore water uptaken Used desorption data to determine pore water

concentrationsn Upwelling and downwelling included by addition of a

pore water flow term

Methods

Ø Model validation:n Bioaccumulation of chlorobenzenes by in situ

exposed L. variegatus simulatedn Chlorobenzene parameters obtained from literature

n Simulated steady state concentrations compared to measured tissue residues

Kinetics of waterborne FLU in L. variegatus

ku = 150 (±14) mL•g-1•h-1

ke = 0.076 (±0.035) h-1ke(m) = 0.13 (±0.0035) h-1

0 20 40 60 800.00

0.02

0.04

0.06

0.08

0.10Bioconcentration Post-exposure elimination

Time (h) Time (h)

20 µg/L5 µg/L20 µg/L50 µg/L

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 3 6 9 12 15 18 21 24 27

Tis

sue

Con

c. (

µm

ol/g

wet

wt)

dCa

dt= kuCw

0e−λt − keCa

St /S0 = Frapid (e−krapid *t

) + Fslow(e−kslow *t) + Fveryslow (e

−kveryslow *t)

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0 100 200 300 400 500 600 700 800

Time (h)

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0 100 200 300 400 500 600 700 800

Time (h)

Trifl

ural

in (

S t /S

0 )

Fluo

rant

hene

(S t

/S0

)Desorption: Lake Huron Sediments

Desorption Rates:10-2 - 10-4 h-1

Rapid t99.9 � 0.5 dSlow t99.9 � 12 d

Very Slow t99.9 � 3 y

Rapid

Slow

Very Slow

10 mg/kg

100 mg/kg

40 mg/kg

200 mg/kg

Organism Sector

Body Burdenuptake from water elimination

keCpw ku

kf

feeding rate

AE

uptake fromfeeding

Sediment Conc

Sediments & Pore Water Sector

Pore WaterConc

desorbedfrom sed

readsorptionto seds

Sediment Conc

rhos phi

removal byanimals

Kp

rho

kdes

reduction byanimals

kf

rho

rho

back to systemby elimination

elimination

phi rhos

lost fromsystem

frac flowing out

phi

Body Burden

Body Burdenuptake from water elimination

ke

Cpw ku

rhos

Pore Water Conc

desorbed

from sed

readsorption

to seds

Sediment Conc

rho

rhos phi

removal by animals

Kp

rho

kf

Body Burden

phi

kdes

feeeding rate

AE

uptake from feeding

Sediment Conc

reduction by animals

kfrho phi

back to system by elimination

elimination

lost from system

frac flowing out

Bioaccumulaton Model

Time (h)

Model output: No pore flow

1. Body Burden (µmol/g wet wt)2. Sediment Conc. (µmol/g dry wt)3. Pore Water Conc. (µmol/mL)

0.00 24.00 48.00 72.00 96.00

1:

1:

1:

2:

2:

2:

3:

3:

3:

0.00

0.25

0.50

0.66

0.66

0.66

0.000145

0.0002

0.000255

1

11 1

2

2

2

2

3 3 3 3

Time (h)

Model output: Full pore flow

1. Body Burden (µmol/g wet wt)2. Sediment Conc. (µmol/g dry wt)3. Pore Water Conc. (µmol/mL)

0.00 24.00 48.00 72.00 96.00

1:

1:

1:

2:

2:

2:

3:

3:

3:

0.00

0.25

0.50

0.65

0.65

0.66

0

0.00015

0.0003

1

1 1 1

2

2

2

23 3 3 3

45%

71%

reduced by

Model predictions and experimental tissue concentrations: Lake Erie, L. variegatus

100 mg/kg dose

200 mg/kg dose

100 Sim 1100 Sim 2100 Sim 3

200 Sim 1200 Sim 2200 Sim 3

Legend

A) Fluoranthene

0.0000.0500.1000.1500.2000.2500.3000.3500.4000.450

0 12 24 36 48 60 72 84 96

Time (h)

Tis

sue

Con

c. (

umol

/g w

w)

B) Trifluralin

0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0 12 24 36 48 60 72 84 96

Time (h)

Field validation for 1,4-dichlorobenzene

Compound Site

Measured body burden (µmol/g wet

wt)

Predicted body burden (µmol/g wet

wt) FactorParameter and value

1,4-DiCB 5 1.02e-03 1.12e-03 1.09 ku = 0.070ke = 0.257FR = 0.01q = 0.10

18 3.74e-03 5.64e-03 1.51 ku = 0.070ke = 0.257FR = 0.01q = 0.10

23 2.31e-04 1.49e-03 6.43 ku = 0.070ke = 0.257FR = 0.01q = 1.00

2.35e-04 1.02 ku = 0.070ke = 0.257FR = 0.00q = 0.25

Conclusions

Ø The model adequately reproduced the Cssobserved in laboratory sediment exposures

Ø Predictions of field bioaccumulation data that were �4 provided a degree of validation of the model

Ø Qualitative description of upwelling and downwelling in the model indicated that this term is an important determining factor in bioavailability

Ø The model simulations suggested that in situ rates of feeding should be measured, as FR is a sensitive parameter.

The Future…

Ø Future research will be designed to improve characterization of GSI to improve the modeling of the impact of upwelling and downwelling on exposure, effects and bioaccumulation.

gsi can affect the bioavailability of sediment-associated ... · gsi can affect the bioavailability...

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