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Total Maximum Daily Loads for Total Maximum Daily Loads for PCBs in the Trinity RiverPCBs in the Trinity River
Segments 0829, 0806, 0841, & 0805Segments 0829, 0806, 0841, & 0805
May 11, 2009May 11, 2009
Kirk Dean, Ph.D., Parsons presenting
Texas Commission on Environmental Quality
Dania Grundmann, TCEQ Project Manager
IntroductionIntroductionSection 303(d) of the federal Clean Water Act Section 303(d) of the federal Clean Water Act (CWA) requires States to identify water bodies that (CWA) requires States to identify water bodies that do not meet applicable water quality standardsdo not meet applicable water quality standards
Pursuant to the CWA and development of the 303(d) Pursuant to the CWA and development of the 303(d) list, the Texas Commission on Environmental Quality list, the Texas Commission on Environmental Quality (TCEQ) is responsible for development of Total (TCEQ) is responsible for development of Total Maximum Daily Loads (TMDLs)Maximum Daily Loads (TMDLs)
IntroductionIntroduction
The goal of a TMDL is to determine the amount (or The goal of a TMDL is to determine the amount (or load) of a pollutant that a body of water can receive load) of a pollutant that a body of water can receive and still support its designated usesand still support its designated uses
That allowable load is then allocated among all That allowable load is then allocated among all sources of pollution within the watershedsources of pollution within the watershed
Measures to reduce the pollutant loads are developedMeasures to reduce the pollutant loads are developed
Impaired Segments/Assessment UnitsImpaired Segments/Assessment Units
Texas Department of State Health Services (TDSHS) Texas Department of State Health Services (TDSHS) issued Aquatic Life Order 14 (ALissued Aquatic Life Order 14 (AL--14) and Fish 14) and Fish Consumption Advisory 25 (ADVConsumption Advisory 25 (ADV--25) in 2002 due to 25) in 2002 due to ““PCBs in fish tissuePCBs in fish tissue”” for 150 miles of the Trinity for 150 miles of the Trinity RiverRiver
As a result the TCEQ placed four segments (nine As a result the TCEQ placed four segments (nine Assessment Units (Assessment Units (AUsAUs)) of the Trinity River on the )) of the Trinity River on the CWA 303 (d) list due to impairment of the CWA 303 (d) list due to impairment of the ““fish fish consumptionconsumption”” designated usedesignated use
Polychlorinated Biphenyls (PCBs)Polychlorinated Biphenyls (PCBs)
A group of 209 compounds, known as PCB congenersA group of 209 compounds, known as PCB congenersFrom 1 to 10 chlorines on 2 connected benzene ringsFrom 1 to 10 chlorines on 2 connected benzene ringsProperties and toxicity vary, but all poorly soluble in waterProperties and toxicity vary, but all poorly soluble in waterTend to be associated with sediments in aquatic systemsTend to be associated with sediments in aquatic systemsHighly resistant to degradationHighly resistant to degradationResidence times in aquatic systems on the order of decadesResidence times in aquatic systems on the order of decades
Polychlorinated Biphenyls (PCBs)Polychlorinated Biphenyls (PCBs)
Sold in the USA under trade name AroclorSold in the USA under trade name AroclorUsed mainly asUsed mainly as
Dielectric fluids in transformersDielectric fluids in transformersHeat transfer fluidsHeat transfer fluidsHeatHeat--resistant hydraulic fluidsresistant hydraulic fluids
Myriad other usesMyriad other usesProduction, distribution and new use banned in Production, distribution and new use banned in 1976 by Toxic Substances Control Act (TSCA)1976 by Toxic Substances Control Act (TSCA)
PCB Conceptual ModelPCB Conceptual Model
Point source effluent
Wet
/dry
de
posit
ion
Wet
/dry
de
posit
ion
Discharges from tributaries
Runoff
Equilibrium partitioning
Discharges
Bottom sedimentsfrom groundwater
Volat
ilizat
ion
BurialResuspension
Dissolved phase
BSAFBSAFBAF Suspended solids
IN
OUT
Phot
odeg
rada
tion
Biodegradation
Point source effluent
Wet
/dry
de
posit
ion
Wet
/dry
de
posit
ion
Discharges from tributaries
Runoff
Equilibrium partitioning
Discharges
Bottom sedimentsfrom groundwater
Volat
ilizat
ion
BurialResuspension
Dissolved phase
BSAFBSAFBAF Suspended solids
IN
OUT
Phot
odeg
rada
tion
Biodegradation
Point source effluent
Wet
/dry
de
posit
ion
Wet
/dry
de
posit
ion
Discharges from tributaries
Runoff
Equilibrium partitioning
Discharges
Bottom sedimentsfrom groundwater
Volat
ilizat
ion
BurialResuspension
Dissolved phase
BSAFBSAFBAF Suspended solids
IN
OUT
Phot
odeg
rada
tion
Biodegradation
BED SEDIMENTS
INFLOWS (UPSTREAM,
TRIBUTARIES,POINT AND NONPOINT SOURCES)
Mass Balance Model Will Mass Balance Model Will Capture the Key ProcessesCapture the Key Processes
OUTFLOWS TO DOWNSTREAM REACHES
SUSPENDED SEDIMENTS
Particle Settling
Sediment Re-suspension
DISSOLVED PCB
ATMOSPHERIC LOSSES + DEGRADATION
BIOTABioaccumulation Factor
Distribution Coefficient
Flux from sediment pore water
PCB fate in water is largely controlled PCB fate in water is largely controlled by their partitioning to sedimentsby their partitioning to sediments
PCBs and water mix like oil and waterPCBs and water mix like oil and waterGiven the chance, PCBs dissolved in water will tend to Given the chance, PCBs dissolved in water will tend to ““sorbsorb””to suspended or bed sediment particlesto suspended or bed sediment particlesOrganic particles can absorb a large amount of PCBs relative Organic particles can absorb a large amount of PCBs relative to most mineral particles. to most mineral particles. This is also why fish This is also why fish ““bioaccumulatebioaccumulate”” PCBs to high levelsPCBs to high levelsAmong minerals, clays can take up more PCB than silt or sand Among minerals, clays can take up more PCB than silt or sand due to greater surface area. due to greater surface area. PCB uptake by sediments is controlled largely by their organic PCB uptake by sediments is controlled largely by their organic content.content.Given enough time, an equilibrium distribution of PCB Given enough time, an equilibrium distribution of PCB concentrations between dissolved and sediment phases occursconcentrations between dissolved and sediment phases occurs
1
10
100
1000
0.1 1 10 100Dissolved Sum of PCB Congeners (ng/l)
Sedi
men
t-Ass
ocia
ted
Sum
of P
CB
Con
gene
rs (n
g/g)
Ambient Samples
Stormwater Samples
WWTP Samples
Sediment-Water DistributionCoefficient
Suspended Sediment : Dissolved Phase Suspended Sediment : Dissolved Phase Partitioning of PCBs in Trinity River WaterPartitioning of PCBs in Trinity River Water
3.2
3.7
4.2
4.7
5.2
5.7
-3.50 -3.00 -2.50 -2.00 -1.50 -1.00Log Sediment Organic Carbon Content
Log
Sedi
men
t: W
ater
Dis
tribu
tion
Coe
ffici
ent (
L/kg
)
Clear Fork
Seg 0806
Seg 0841
Seg 0805 Upper
Seg 0805 Lower
Log Distribution Coefficient =Log Organic Carbon Content + 6.4
Bed SedimentBed Sediment--Dissolved Phase PartitioningDissolved Phase Partitioning
Data CollectionData Collection March March –– August 2008August 2008
InIn--stream PCB concentration measurementsstream PCB concentration measurements18 measurements at 13 main stem sites18 measurements at 13 main stem sites
Sediment PCB concentration measurements Sediment PCB concentration measurements 77 measurements at 32 main stem and 43 tributary sites77 measurements at 32 main stem and 43 tributary sites
PCB loads from wastewater dischargesPCB loads from wastewater discharges8 measurements at 4 facilities8 measurements at 4 facilities
PCB loads from storm waterPCB loads from storm water9 measurements at 5 sites9 measurements at 5 sites
Individual PCB congeners measured by EPA Method 1668AIndividual PCB congeners measured by EPA Method 1668A-- results presented reflect sum of results presented reflect sum of ““detecteddetected”” congenerscongeners
0.0
1.0
2.0
3.0
4.0
5.0
-10 0 10 20 30 40 50 60 70 80 90 100 110 120Project Distance (miles)
Sum
of P
CB
con
gene
rs (n
g/L)
Total PCB in waterLow-Flow Total PCB in WaterDissolved PCB in waterLow-Flow Dissolved PCB in Watersegment boundaries
FM 85SH 34
Dowdy Ferry Rd
S. Loop 12
FM 157 (Collins St.)Beach St
W. Loop 12
Segment0806
Segment0841
Segment 0805Seg0829
water quality criterion for total PCB
PCB Levels in Trinity River WaterPCB Levels in Trinity River Water
0%
20%
40%
60%
80%
100%
0% 20% 40% 60% 80% 100%
Stream Flow Percentile During Sampling (Compared to 1988-2008 Flows)
Frac
tion
of S
tream
PC
B L
oad
Ass
ocia
ted
with
S
uspe
nded
Par
ticle
s
Low Flows High Flows
Spring 2008 Survey Points
Summer 2008 Low-FlowSurvey Points
Flow Dependence of Suspended PCB LevelsFlow Dependence of Suspended PCB Levels
0
1
10
100
-15 -5 5 15 25 35 45 55 65 75 85 95 105 115 125
Project Distance Downstream of Confluence of West and Clear Forks (miles)
Sum
of P
CB
Con
gene
rs (u
g/kg
)
SH 34
S. Loop 12
SH 360
Dowdy Ferry
above Tenmile Ck
W. Beltline
Greenbelt Rd
Beach St.
below Lake Worth
W. Loop 12
FM 85
Handley Rd
Seg 0806/0829 Seg 0841 Seg 0805
PCB Levels in Trinity RiverPCB Levels in Trinity River Bed SedimentsBed Sediments
100
1,000
10,000
-15 -5 5 15 25 35 45 55 65 75 85 95 105 115 125
Project Distance Downstream of Confluence of West and Clear Forks (miles)
Sum
of P
CB
Con
gene
rs (u
g/kg
OC
)
SH 34
S. Loop 12
SH 360
Dowdy Ferry
above Tenmile Ck
W. Beltline
Greenbelt Rd
W. Loop 12
Beach St.
below Lake Worth
FM 85
East 1st St
Organic Carbon Normalized PCB Organic Carbon Normalized PCB Levels in Trinity River Bed SedimentsLevels in Trinity River Bed Sediments
0.1
1
10
100
1000
10000
-15 -5 5 15 25 35 45 55 65 75 85 95 105 115 125Project Distance Downstream of Confluence of West and Clear Forks (miles)
Sum
of P
CB
Con
gene
rs (u
g/kg
)
2008 data
1974-75 data
1980's data
SH 34
SH 360
Dowdy Ferry
Greenbelt Rd
Beach St.
below Lake Worth
FM 85
Handley Rd
Historical Bed Sediment PCB LevelsHistorical Bed Sediment PCB Levels
0
2
4
6
8
10
12
14
16
18
20
Big Fos
sil Cree
k
Big Foss
il Cree
k
Purcey
St drai
n
Purcey
St drai
n
Able Pum
p stat
ion
Able Pum
p stat
ion
Hampto
n pum
p stati
on
Hampto
n pump s
tation
Parson
s Slou
ghFW Villa
ge C
reek
FW Village
Cree
kTRA C
entral
TRA Cen
tral
Dallas
Cen
tral
Dallas C
entra
l
Dallas S
outhsid
e
Dallas
Southsid
eTo
tal P
CB
(ng/
L) Stormwater WWTP Effluent
Average River Conc. 1.85 ng/L
51 ng/l
PCB Sources: PCB Sources: StormwaterStormwater and WWTP Effluentand WWTP Effluent
0
10
20
30
40
50
60
70
80
90
100
PurceyStreetDrain
MarineCreek @Marine
Creek Park
MarineCreek
LebowCreek
SycamoreCreek at E.Seminary
Dr
SycamoreCreek atUS 287
SycamoreCreek at
Lancaster
Unnamedtributary @Haltom Rd
Big FossilCreek
Little FossilCreek
VillageCreek
Sum
of P
CB
Con
gene
rs in
Sed
imen
t (ug
/kg)
Segment Average
PCB Levels in Bed Sediments of PCB Levels in Bed Sediments of Tributaries to Segment 0806/0829Tributaries to Segment 0806/0829
0
10
20
30
40
50
60
70
80
90
100
Walker B
ranch
Sulphur B
ranch
Unnamed
tribu
tary a
t Mosie
r Vall
ey R
d
Unnamed
tribu
tary a
t S. M
ain St. i
n Eules
sJo
hnso
n Cree
kDalw
orth C
reek
Bear Cree
kBear
Creek
Mounta
in Cree
k
Mounta
in Cree
k @ W
est J
efferso
n Blvd
Delaware
Creek
Elm Fork
@ C
aliforni
a Cros
sing
Elm Fork
above
Carro
lton D
amElm
ForkSum
of P
CB
Con
gene
rs in
Sed
imen
t (ug
/kg)
Segment Average
PCB Levels in Bed Sediments of PCB Levels in Bed Sediments of Tributaries to Segment 0841Tributaries to Segment 0841
0
10
20
30
40
50
60
70
80
90
100
Delta S
ump
Hampto
n Sum
pBak
er Sum
pPav
aho S
ump
Coombs
Cree
kCha
rlie Sum
pAble
Sump
Cedar
Creek
White R
ock C
reek @
US 17
5
White R
ock C
reek
Roche
ster S
ump
Honey
Spring
s Bran
chElam
Cree
kFive
Mile
Cree
kPrai
rie C
reekTen
Mile
Cree
kPars
ons S
lough
Parson
s Slou
ghEas
t Fork
Red O
ak C
reek
Sum
of P
CB
Con
gene
rs in
Sed
imen
t (ug
/kg)
Segment Average
PCB Levels in Bed Sediments of PCB Levels in Bed Sediments of Tributaries to Segment 0805Tributaries to Segment 0805
ObservationsObservations
Total PCB levels in water exceeded water quality Total PCB levels in water exceeded water quality criteria in 13 of 18 samples from the Trinity criteria in 13 of 18 samples from the Trinity RiverRiver
Total PCB levels in storm water from older, Total PCB levels in storm water from older, densely developed urban areas are much higher densely developed urban areas are much higher than those inthan those in--stream, but low in rural and stream, but low in rural and suburban areassuburban areas
Total PCB levels in wastewater effluent were Total PCB levels in wastewater effluent were generally lower than ambient levels in the rivergenerally lower than ambient levels in the river
ObservationsObservations
PCB levels in sediment appear to have declined PCB levels in sediment appear to have declined since the 1970s and 1980s in Segment 0805 and since the 1970s and 1980s in Segment 0805 and 0841, but perhaps not in Segment 08060841, but perhaps not in Segment 0806
The range in PCB levels in tributary sediments The range in PCB levels in tributary sediments indicates continuing local sources in some areasindicates continuing local sources in some areas
TMDL Process and Project ScheduleTMDL Process and Project Schedule
Next Steps: Modeling and TMDL Next Steps: Modeling and TMDL DevelopmentDevelopment
Model under development to:Model under development to:assist in determining the TMDL and quantify pollutant loadsassist in determining the TMDL and quantify pollutant loadsevaluate future loading scenarios and load reductionsevaluate future loading scenarios and load reductions
InstreamInstream model is a multiplemodel is a multiple--box mass balance modelbox mass balance modelInstreamInstream segmentation and hydraulics based on TCEQ segmentation and hydraulics based on TCEQ QualQual--TX modelsTX modelsWatershed runoff and suspended sediment loading from Watershed runoff and suspended sediment loading from tributaries using GWLF modeltributaries using GWLF modelModeling expected to be complete late this monthModeling expected to be complete late this monthModeling report expected this summerModeling report expected this summer
Questions?Questions?
For further questions:For further questions:
Dania Dania [email protected]@tceq.state.tx.us512512--239239--34493449