TMDLs for PCBs for the Delaware River Estuary · PCB loadings at head of tide (Trenton) have a...
Transcript of TMDLs for PCBs for the Delaware River Estuary · PCB loadings at head of tide (Trenton) have a...
TMDLs for PCBsfor the Delaware River Estuary
Thomas J. Fikslin, Ph.D., Manager Modeling, Monitoring and Assessment Branch
Delaware Estuary
2
Background
Delaware Estuary is 133 miles long and is bordered by DE, NJ and PA
1998 – All three states listed the Delaware Estuary as impaired requiring the development of TMDLs.
Spring 2000 – DRBC designated the lead agency to develop the TMDLs for PCBs by the court-ordered deadline of Dec. 15, 2003.
Major boundaries: Delaware River at Trenton, NJ; Schuylkill River; C&D Canal; and the Ocean.
Point sources: 94 industrial and municipal facilities, CSOs, and MS4s.
Tributaries: 22 Contaminated sites: ~ 50 Air flux and deposition.
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4
Homolog Distribution in Estuary Zones - 2003White Perch
0.0
50.0
100.0
150.0
200.0
250.0
Mono Di Tri Tetra Penta Hexa Hepta Octa Nona Deca
PCB Homologs
Nan
ogra
ms
per g
ram
(wet
wei
ght)
Zone 2 Zone 3 Zone 4 Zone 5
5
Median Ambient PCB ConcentrationsStage 1 - 2002 to 2003
Tetra through Hexa Homolog Distribution
0
200
400
600
800
1000
1200
1400
2 3 4 5 6
Estuary Zone
pico
gram
s pe
r lite
r (pg
/l)
Tetra Penta Hepta Hexa
Water QualityCriterion - 16 pg/L
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Principal Mass Loadings and Fluxes
Contaminated Site Loads
Upstream Boundary LoadDelaware River at Trenton, NJ
SedimentFlux
AtmoshphericWet / Dry
Deposition
AtmoshphericGas phase
flux
Upstream Boundary LoadSchuylkill River
Non-Point Source LoadsTributary Loads
Point Discharge Loads
Sediment
C&D Canal(tidal boundary)
Ocean BoundaryMouth of Delaware Bay
CSOs
LEGEND
External Loads(forcing functions)
Fluxes and tidal boundaries
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Themes Importance of the Water Quality Target Importance of Source Identification and
QuantitationNeed for a Model Importance of the Sediment Reservoir Developing Complex TMDLs Staged TMDL Development for the
Delaware Estuary Non-numeric permit requirements
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TMDLs must be based upon the most stringent water quality criteria applicable to the receiving water in order for the designated uses of the water body to be met.
In interstate waters like the Delaware Estuary, inconsistent uses and criteria complicate the identification of the most stringent criterion.
In the Delaware Estuary, criteria for the protection of human health and wildlife were potentially the most restrictive.
Importance of theTMDL Target
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Water Quality Criteria
Zones 2 & 3 Zone 4 & Upper Zone 5
Rest of Zone 5
Existing DRBC Criteria
44.4 pg/l 44.8 pg/l 7.9 pg/l
Existing PCB criteria creates a critical point in Zone 5. This has significant effects on the available assimilative capacity (the TMDLs).
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0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 20 40 60 80 100 120 140
River Mile
Con
cent
ratio
n, p
g/L
Median_99_100th year water column target
Zone 6 Zone 5 Zone 4 Zone 3 Zone 2
Penta-PCB Water Column Concentrations at TMDL Loads, 100 year simulation
11
Water Quality Criteria DRBC staff has developed a revised water
quality criterion of 16 pg/L that is applicable to all zones.
This criterion utilizes the 2000 U.S. EPA methodology for deriving human health criteria, and incorporates: the upper bound estimate of the cancer potency
factor of 2.0 (mg/KG)/day, site-specific fish consumption rates, and a site-specific bioaccumulation factor.
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PCB Criteria and TMDLs in Delaware Estuary
0
10
20
30
40
50
0 20 40 60 80 100 120 140
River miles from the mouth of the bay
conc
entr
atio
n, p
g/L
Existing Criteria TMDL_Stage_1 Proposed Criteria TMDL_Stage_2(?)
44.4 pg/L44.8 pg/L
7.9 pg/L
16 pg/L
Unused assimilative
capacity
Fully utilize assimilative
capacity
Why develop a Model?ì Gain understanding:
Determine PCB load-response relationships.
Determine principal controlling processes.
Address management questions:Determine PCB TMDL for each zone. Allocate TMDLs among sources.Assess the impact of load reduction
strategies. 14
Delaware River PCB Model (DELPCB)
Modified version of DYNHYD5/TOXI5 EPA-supported and widely used for toxic
chemical TMDLs and contaminated sediments.Model formulations/code extensively tested and
assessed with observations at numerous sites. Builds upon modeling work at other sites:
Green Bay Mass BalanceStudyUpper Hudson River RI/FSFox River RI/FS
Kalamazoo RiverRI/FSNew York Harbor
CARP Model15
Delaware River PCB Model (DELPCB)
Represents water column and sediments One-dimensional in longitude87 spatial segments
Time-variable HydrodynamicsTidal heightsChloride mass balance
Organic carbon sorbent dynamicsParticulate carbon (biotic and detrital)Dissolved organic carbon
Penta PCB homolog 16
Short-term Calibration for penta-CB
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1
10
100
1,000
10,000
1970 1975 1980 1985 1990 1995 2000 2005
Time
Tota
l-PC
B [n
g/L]
Model 80%Model 50%Model 20%Data
Decadal Scale Calibrationfor penta-PCB
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Key Findings The principal sources of PCB loadings are non-
point source runoff, point sources and the mainstem Delaware River.
The flux of PCBs between the gas phase in the atmosphere and dissolved PCBs in the water is a significant process affecting the achievement of the TMDLs.
PCB loadings at head of tide (Trenton) have a significant influence in the tidal Delaware River.
Water column PCBs are strongly influenced by loadings and sediments. 19
Summary points
Model for PCBs is developed and calibrated.Model is scientifically credible. Collaboration with Delaware Estuary TMDL
CoalitionAvoided adversarial process and a competing model
Model was used to develop Stage 1 PCB TMDL, but Stage 2 is necessary to address uncertainties.
Model can be extended to other contaminantsand to other watersheds.
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Source Identification & Quantitation
Identifying and quantifying PCB sources using congener-specific analytical methods has several benefits:Allows prioritization of sources for load reductions.Reduces the uncertainty in model inputs.Permits fingerprinting of sources.Allows permittees/site owners to track the
effectiveness of pollutant minimization activities.
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Penta-PCB Load by Source CategorySept 2001 through March 2003
9.22
6.56
5.26
4.00 3.903.47
2.34 2.19
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Non-PointSource Runoff
PointDischarges
Delaware atTrenton
Schuylkill ContaminatedSites (revised)
All OtherTributaries
Atmosphericwet and drydeposition
CSOs
Source Category
577-
day
Pent
a PC
B L
oad
(kg)
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Cumulative 2005-06 Penta-PCB LoadingsNPDES Discharges (Total n=128)
48
57
63
69
7580
8486
88 89 91 92 93 94 94 95 96 96 97 97 97 97 98 98 98
20
30
40
50
60
70
80
90
100
110
Val
ero
Ref
inin
g
PWD
-NE
City
of W
ilmin
gton
U.S
. Ste
el
PWD
-SW
CC
MU
A
AM
TRA
K R
ace
St./P
enn
Coa
ch
PWD
-SE
Tren
ton
Dup
ont-C
ham
berW
orks
PQ C
orpo
ratio
n
Met
ro M
achi
ne
Dup
ont-R
epau
no
Dup
ont-C
ham
berW
orks
Ham
ilton
Tow
nshi
p
PQ C
orpo
ratio
n
Will
ingb
oro
Mun
icip
al U
tiliti
esA
utho
rity
Mor
risvi
lle W
WTP
PQ C
orpo
ratio
n
DEL
CO
RA
Low
er B
ucks
Cou
nty
Mun
icip
alA
utho
rity
Solu
tia
GC
UA
Del
ran
Sew
erag
e A
utho
rity
Dup
ont-R
epau
no
Perc
ent (
%)
N = 16
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Establishing TMDLsTMDLs are estimates of the loadings of each
of the PCB homologs that can enter the estuary and still meet the current water quality criteria. They are projected loadings from all sources based upon assumptions called design conditions.Since current concentrations of PCB homologs
are 500 times higher than the water quality criteria, the TMDLs and associated individual WLAs and LAs will be proportionately less.
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Allocate 5% of each of the zone TMDLs to a margin of safety (MOS).Allocate to the contaminated sites category.Allocate the remainder of the zone TMDLs
to a WLA portion and a LA portion based upon the current percentage contribution for each of the source categories to each zone during the period February 1, 2002 to January 31, 2003.
Summary of Approach for Stage 1
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Using the estuary-wide ratio of penta-PCBs to Total PCBs from ambient data collected in the Delaware Estuary, the zone-specific, penta-PCB TMDLs were scaled up using a fixed ratio of 1:4 to calculate the TMDL.
Summary of Approach for Stage 1
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Ratio of Penta-PCBs toTotal PCBs in Ambient Samples
0.15
0.20
0.25
0.30
0.35
2 3 4 5
Zones
Pent
a to
Tot
al P
CB
Rat
io
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Penta PCB Water Target
Assimilative Capacity by Sedimentation0.500 pg/L
1.975 pg/L Usable Assimilative
Capacity
0.183 pg/L
2.292pg/L
Trenton
Schuylkill
Zone 2
Zone 3
Zone 4
Zone 5
Contribution by the Mouth of the Bay and C&D Canal
MOS
C. Site
Open BC
Allocation of the Assimilative Capacityat the Critical Location
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Stage 1 TMDLs forTotal PCBs
Estuary Zone TMDL WLA LA MOSmg/day mg/day mg/day mg/day
Zone 2 257.4 5.0 239.5 12.9
Zone 3 17.8 4.9 12.0 0.9
Zone 4 56.7 5.2 48.7 2.8
Zone 5 48.1 13.3 32.4 2.4
Sum 380.0 28.3 332.6 19.0
Approach for EstablishingStage 2 TMDLsThe approach for establishing Stage 2 TMDLs
is expected to be different than that used in Stage 1.Some of the reasons for this are:A revised human health criteria for total PCBs has
been developed that does not produce a sharp transition between zones.
An alternative allocation procedure for both the aggregate WLAs and LAs, and the individual WLAs and LAs that is more equitable will be needed. 30
Approach for EstablishingStage 2 TMDLs
TMDLs for total PCBs for each zone will be the sum of the TMDLs for four homologs without extrapolation from Penta-PCBs.
Alternative source reduction strategies thatresult from either the PCB Minimization Plans required in Stage 1 or the efforts of the PCB Implementation Committee will need to be considered , where appropriate, in allocating the zone TMDLs.
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Progress to Date
DRBC implemented the Stage 1 TMDLs by requiring point sources to conduct additional monitoring using low level techniques (Method 1668A). The results of this monitoring have been submitted and assessed.
DRBC passed regulations in May 2005 requiring point source dischargers to submit and implement PMPs. 42 dischargers are initially required to submit the plans.
Regulations can be applied to any point and non-point source that the Commission determines has an “adverse impact” on the water resources of the Basin.
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Achieving Water Quality Criteria
Reductions in PCB loadings will not immediately result in lower ambient water concentrations or in reduced tissue levels of PCBs in resident fish species.
This is due to the continuing flux of PCBs from the sediments to the water column. As solids uncontaminated by PCBs settle to the bottom, this flux will ultimately reach equilibrium with the water column.
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100 year projection with all sources set to zero
0.1
1
10
100
1000
10000
2001 2011 2021 2031 2041 2051 2061 2071 2081 2091 2101
Years
Tot
al P
CB
Con
cntr
atio
n (p
g/L
)
Zone 3 Zone 2 Proposed Criteria
June 2021
June 2031
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Achieving Water Quality Criteria
Reductions in PCB loadings will not immediately result in lower ambient water concentrations or in reduced tissue levels of PCBs in resident fish species.
This is due to the continuing flux of PCBs from the sediments to the water column. As solids uncontaminated by PCBs settle to the bottom, this flux will ultimately reach equilibrium with the water column.
A long-term strategy for permitting point source discharges and addressing non-point sources such as contaminated sites and air sources is needed to ensure continued progress in reducing PCBs.
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Contact Information:
[email protected](609) 883-9500, ext.253
Information on the TMDLs, model development, sampling and analytical information, and PMP requirements and resources are available on the DRBC website at:
www.drbc.net36
Stage 2 Implementation Requirements
Build upon the monitoring and PMP requirements of Stage 1 TMDLs.
Incorporate the concept of an Action Level.• Purpose - to elicit a prompt response to elevated
PCB concentrations above those achieved.• Establish duration and magnitude of elevated
concentrations.• Document actions taken and return to PCB
concentrations previously observed, or proposed actions to be included in a revised PMP.
NPDES Permitting Strategy Two Response Levels Approach
• Based upon the last 10 data points collected under normal operating conditions.
• Monitoring Trigger Level (MTL) - based upon 95th confidence interval of the median. Objective is to obtain additional monitoring data given the
low frequency of permit monitoring required. Permittee has primary responsibility – Reporting to DRBC
required.
• Action Level - based upon maximum projected effluent concentration. Objective is to require monitoring and submittal of a report. Permittee and DRBC/State permitting agency share
responsibility.
46 % reduction
10 Dischargers Representing 90% of Point Source PCB Loadings in the Estuary
42,852
23,058
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
2005 Point Source Load Current Point Source Load
mg/d
Incremental Progress Reductions in Loadings from Non-Point
SourcesT Removal of ~40,000 lbs. of PCBs from tidally-influenced
wetland adjacent to tributary creek.T Removal of ~8,000 lbs. from NPL industrial site.T Inventory of Superfund sites - DelTriP
http://www.state.nj.us/drbc/about/public/publications/deltrip.html
In 2013, DE and NJ relaxed fish consumption advisories to 1 meal per year in Zone 5.
Ambient water concentrations did not change significantly as expected.