Post on 19-Aug-2020
transcript
Delaware River Basin Commission
Role of Sediments in Managing PCBs in the Delaware Estuary
Gregory J. Cavallo, P.G.Thomas J. Fikslin, Ph.D.
NJ Monitoring CouncilSeptember 21, 2016
Why sample sediment?
PCBs concentrations from the Delaware Estuary collected for the Delaware Estuary Benthic Inventory (DEBI) project (2008) and DRBC efforts in 2010
Compare PCB homolog signatures
Technical/Management Implications
Discuss 2016 Sediment Sampling Effort
Presentation Outline
Roles of Sediment
Interaction with water columnMediating the water column response
Integrator of changes in water column concentrations
Provide data on trends
Providing assimilation capacity
Pollutant removal mechanism
Why Sample Sediments?
Principal Mass Loadings and Fluxes
Contaminated Site Loads
Upstream Boundary Load
Delaware River at Trenton, NJ
Sediment
Flux
Atmoshpheric
Wet / Dry
Deposition
Atmoshpheric
Gas phase
flux
Upstream Boundary Load
Schuylkill River
Non-Point Source LoadsTributary Loads
Point Discharge Loads
Sediment
C&D Canal
(tidal boundary)
Ocean Boundary
Mouth of Delaware Bay
CSOs
LEGEND
External Loads
(forcing functions)
Fluxes and tidal boundaries
Past and current PCB loadings of PCBs result in the accumulation of contaminated sediment.
Even if current loadings are substantially reduced, the water column will not immediately respond due to contributions of PCBs from the sediment.
As clean sediments enter the water body, sediment concentrations will ultimately be in equilibrium with the water column concentrations.
Mediating Water Column Response
Current PCB Loading Condition
10
100
1000
10000
2016 2026 2036 2046 2056 2066 2076 2086 2096 2106 2116
To
tal P
CB
co
nce
ntr
ati
on
(p
g/L
)
Years
Projected, median Total PCB concentrations (Penta Homolog Model)Four BCs and loads @ current condition ; with current Sediment & Water Column
Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 PCB WQC (16 pg/L)
Effect of Sediment Flux
0.01
0.1
1
10
100
1000
10000
2016 2026 2036 2046 2056 2066 2076 2086 2096 2106 2116
Tota
l PC
B c
on
cen
trat
ion
(pg/
L)
Years
Projected, median Total PCB concentrations (Penta Homolog Model)4 BCs and external loads @ zero; Sediment & Water column @ current Conc.
Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 PCB WQC (16 pg/L)
Sediment samples were collected as part of the Delaware Estuary Benthic Inventory (DEBI) Program in Summer of 2008
Surface grab samples
Young stainless steel grab
187 samples were received by the DRBC
Samples were collected in Zones 4, 5 and 6with an emphasis in Zones 5 and 6
DEBI Sediment Sample Collection
52 samples were analyzed for PCBs
4 samples analyzed were from Zone 4
34 samples analyzed were from Zone 5
14 samples analyzed were from Zone 6
PCB samples were analyzed for all 209 congeners using EPA Method 1668 revision A by Axys Analytical Laboratories
Analytical results are provided in pg/g dry weight
Estimated Detection Limits of <1 pg/g (ppt)
90% of all congeners detected
PCB Analysis
Total PCB Concentrations pg/g
(ppt) dry weight
PCB Homolog Distribution upper Zone 5
PCB Homolog Distribution Zone 4
Nona and deca concentrations represent > 90% of all PCBs
mono
di
tri
tetra
penta
hexa
hepta
octa
nona
deca
PCBHomologs
PCB Homolog Distribution Lower Zone 5
PCB Homolog Distribution Zone 6
Prominent
deca
signature
DEBI effort extended to Zone 2, 3 and upper Zone 4
29 additional samples were collected and analyzed for PCBs 11 samples collected in Zone 4 9 samples collected in Zone 3 9 samples collected in Zone 2
PCB samples were analyzed for all 209 congeners using EPA Method 1668 revision A by Axys Analytical Laboratories
Additional Samples collected in 2010
DEBI 2008 Samples
DRBC 2010 Samples
DRBC Samples Collected in 2010
Samples collected in 2008 and 2010
Comparison of PCB Concentrations
Phila
delp
hia
Pa.
Wilm
ingto
n
De.
Tre
nto
n N
J.
ppb
Current and expected penta-PCB concentrations in sediment layer when the TMDLs
are achieved
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
0 20 40 60 80 100 120 140
River Mile
Co
cen
tra
tio
n,
mg
/L
Current_Sediment_PCB Concentration Sediment_PCB_Concentration after TMDLs
Zone 6 Zone 5 Zone 4 Zone 3 Zone 2
pp
m
2016 SedimentSampling Locations
11/7/2016
DRBC Staff Sediment Sampling
QUESTIONS?