TRB_AC60-Stormwater and Sediment-FINAL

Evaluation of the Effect of Highway and
Bridge Facilities on Sediment Quality
Presented at Transportation Research Board Committees on
Resource Conservation & Recovery and Geo-Environmental
Processes
2016 Summer Workshop
July 26-29, 2016 | Asheville, N.C.
Chris Moody, R.G., Philip Spadaro, R.G., Jason Dittman, Ph.D.,
Kristi Maitland
1

Copyright 2016 The Intelligence Group
Talk Outline
• Issue background
• Introduction and Identification of Common COCs
Associated with Highway Stormwater
– Sources including roadway materials and
architectural coatings
• Methods for Calculating Stormwater Loading
• Methods for Determining Sediment Deposition Zones
from Stormwater Outfalls
• Use of Modeling Approach for Predicting Sediment COC
Contribution from Stormwater
– Using concentrations and solids measurements is the
technically incorrect way to complete these studies
2

Evaluation Flow Chart
3
Identify COCs
Measure
Concentrations
in Stormwater
Calculate COC
mass per unit
time
Determine
near field
deposition area
Model mass to
deposition area
Compare to
Cleanup Goals
or Background

• International Forensics + Investigations Consulting Firm
• 50+ staff
• Founded in 1999
• HQ: Bedminster, NJ
• Key Offices:
• Seattle, WA
• Portland, OR
• Syracuse, NY
• Washington, DC
• Philadelphia, PA
• Minneapolis, MN
• New York City, NY
• Working with DOTs on Superfund related issues for 10+ years
The Intelligence Group - Background

Issue Background
• June 2010 – Order on Summary Judgement – WSDOT was liable under
CERCLA for arranging stormwater with hazardous substances into the
Thea Foss Waterway (Tacoma, WA)
• February 2011 – Oregon DOT received General Notice Letter (GNL)
from EPA on Portland Harbor Superfund Site (Portland, OR)
• November 2011 – Caltrans – Civil Settlement – cleanup of sediment in
Mountain Lake near San Francisco, CA
– Highway 1 operation contaminated the lake with lead, copper and zinc
– $13.5 million settlement
• December 2013 – WSDOT received GNL from EPA on Lower
Duwamish Waterway Superfund Site (Seattle, WA)
• 2015 – City of Spokane Study – PCBs in several roadway materials
• Recontamination from stormwater sources identified at several CERCLA
sites
– Old grout source of PCBs
– PCBs in architectural coatings
– Phthalates ubiquitous
6

Transportation- COCs and Sources
• Tire wear: zinc & BEHP
• Brake wear: copper, zinc, BEHP
• Corrosion and wear: metals, PAHs, zinc
• Exhaust: historically lead, currently PAHs, some PCBs
• Roadway Materials: TSS and other (see below)
– PAHs – Asphalt
– PCBs – Striping Paint
– Zinc – Guardrails & drainage pipes
• De-icing products and sands: chloride, TSS, PCBs
• Atmospheric Deposition – PCBs, BEHP, mercury, PCBs,
pesticides
6

• Potential COCs found in coatings:
– Lead (Made paint more flexible, water resistant)
– arsenic,
– cadmium,
– chromium,
– copper,
– zinc
• PCBs (historical and current)
• Phthalates
• Mercury (historical)
Architectural Coatings-COCs and
Sources
8

• Between 1940s and until the ban in 1979,
PCBs were added as a plasticizer to paints
at ranging between 5% and 30%
– Increased Adhesion
– Increased Luster
– Reduced Drying Time
– Corrosion resistance
– Good Heat and Humidity resistance
– Increased antifungal properties
• Known by its trade name (Parlon) it was
used in many fields of applications
– chemical resistance coatings
– masonry paints
– traffic paints,
– marine type paints
– protective and decorative coatings for steel
structures, railway tank and gondola cars
PCB use in Coatings
9

• In addition to PCBs being intentionally added to paints and caulks, PCBs
were also inadvertently created in the production process of certain
pigments
• Under current TSCA rules, PCBs are currently allowed at less than 25
mg/kg, with a 50 mg/kg maximum in pigments
• Analysis of commercial paint pigments purchased in Chicago-area retail
stores by Hu and Hornbuckle (2009) indicates that PCB congeners are
found in azo and phthalocyanine pigments
• Much lower concentrations than when intentionally added
• Mostly found in green paints, but also some blues, yellows, oranges and
reds
PCB use in Coatings
10

• Study focus was on presence of hazardous levels of PCBs >50 mg/kg
• Looked at bridge coating systems before 1980
• 10% of the pre-1980 coating bridges were randomly selected (out of
976)
• Two of the 98 bridges sampled had individual samples > 50 mg/kg of
PCBs
– 110 mg/kg
– 131 mg/kg
• 32 of the 98 had reportable detections of PCB Aroclors
– 0.59 mg/kg to 131 mg/kg
• The average concentration of the most commonly detected PCB Aroclor
(1254) was 10.7 mg/kg
Recent Testing from MnDOT
11

Conceptual Site Model (CSM)
12
Bridge Coating
Leaching Dust Paint Chips Outfall Catch Basin
Contaminants in the paint may leach into the rainwater
and deposit directly into the river. Rainwater may also
carry dust or paint chips flaking off the bridge into the
river.
Dust particles
forming on the paint
coating may be
carried to the river
via wind or
rainwater.
The paint coating is
flaking and paint chips
may enter the river
either via wind or
rainwater.
Rainwater, dust, and paint
chips may be collected in
the stormwater system
and then enter the river
through outfalls.

Summary of COCs
• Several sources of Zinc,
PAHs
– Therefore found relatively
higher levels
• PCBs and BEHP evolving
COCs due to other recently
found sources
– Roadway Striping Paint
13

14
Identify COCs
Measure
Concentrations
in Stormwater
Calculate COC
mass per unit
time
Determine
near field
deposition area
Model mass to
deposition area
Compare to
Cleanup Goals
or Background

Methods for Calculating Stormwater
Mass
• Example data needs for modeling:
watershed drainage area,
impervious cover, concentrations of
COCs in stormwater, annual
precipitation
• A number of stormwater pollutant
models: STEPL, AVGWLF,
WINNSLAMM, SELDM, PLOAD, the
P8 Urban Catchment Model, and
the Simple Method.
• The type of model selected
depends on site variables such as
scale, types of land use, basin
specific source identification, actual
measurement of storm events,
etc…
15

Comparison of Select Methods
Model Description Developer
STEPL: Spreadsheet Tool for
Estimating Pollutant Load
Watershed-scale hydrogeology and water quality
model. Spreadsheet tool. User-friendly
Tetra Tech
AVGWLF: ArcView Generalized
Watershed Loading Function
Model
GIS-based watershed runoff model. Evaluates
impact of various land uses on water quality
Penn State Institute of Energy
and the Environment
WinSLAMM: Source Loading and
Management Model for Windows
Urban stormwater quality model that evaluates
runoff volume and pollution loading for each source
area within each land use per rainfall event.
PV & Associates, LLC
SELDM: Stochastic Empirical
Loading and Dilution Model
Empirical model based on data and statistics, rather
than physiochemical equations.
U.S. Geological Survey &
Federal Highway
Administration
PLOAD: Pollutant Loading
Application
GIS based model that estimates nonpoint sources
of pollution on an annual average basis
CH2MHILL
P8 Urban Catchment Model Tool for predicting the generation and transport of
pollutants in stormwater runoff within urban
watersheds.
IEP
SWMM: The EPA Storm Water
Management Model
Catchment based model that estimates flow and
pollutant loads from baseflow or runoff
EPA and CDM
SIMPLE Model Empirical technique for estimating stormwater
pollutant loads from urban areas
Schueler
16

Simple Method
• The Simple Method provides a general planning level
estimate of likely pollutant export from areas at the scale
of a development site, watershed, or subwatershed.
More sophisticated modeling may be needed to analyze
larger and more complex watersheds.
• The Simple Method only estimates pollutant loads
generated during storm events. It does not consider
pollutants associated with baseflow volume.
• Used by NYDEC, WSDOE, Michigan DOT, New
Hampshire DES
17

Methods for Determining Sediment
Deposition Zones from Outfalls
• Simple Estimation
• Hydrodynamic Modeling
• Particle Tracking
18

Methods for Determining Sediment
Deposition Zones from Stormwater Outfalls
Use data such as bathymetry, percent fines, etc… to estimate
depositional areas
Outfall 2
19

Hydrodynamic Models
• Example models that are suited to investigate
hydrodynamics, sediment transport and
morphology, etc…
– 3D hydrodynamic Delft3D model
– Mike21 and Mike3
– EFDC
20
• Bathymetry data of the Study Area
• Boundary conditions (e.g., flow
discharge, water level, etc…)
• Particle size distribution of released
sediments from outfalls
• Hydrographs of flow from outfalls of
interest

Particle Tracking
• Method for assessing the
transport pathways for a
variety of sediments (silts,
sands, gravel, etc.) across
spatial and temporal scales
• Marking or tagging of natural
or artificial sediments with an
identifiable signature (e.g.,
fluorescence)
• Evaluation of the spatial and
temporal distribution of
“tagged” sediment allow for
analysis of transportation
pathways of sediment
21

Models used for Mass Loading to
Depositional Area
• Hydrodynamic and water quality models integrate inputs from point and
sources to determine sediment impacts
• Officer and Lynch
– Pioneering depositional model looking at the chemical and biological reactions such as burial
rates, bioturbations effects and benthic sediment-water exchanges
• WASP: Water Quality Analysis Simulation Program
– WASP has a versatile structure, and has been applied to studies involving all of the Great
Lakes
• EFDC: Environmental Fluid Dynamics Code
– USEPA has used EFDC in conjunction with WASP to develop TMDLs for estuaries across
the country
• SEDCAM
– Evaluation of potential for recontamination after sediment cleanup at the Diagonal combined
sewer overflow (CSO) discharging into the Duwamish River.
– Study of varying concentrations of organic compounds through analysis of carbon-
normalized concentrations present in deposited sediment as well as the mixing layer
22

Comparison of Predicted COC Concentration
from Stormwater to Recontamination or
Remedial Goals
• Important is to use mass and then get to concentration
using model
• Several statistical methods
• Background or regulatory threshold
– one-sample hypotheses tests (if more data)
– point-by-point (if less than 4-6 points)
• No regulatory threshold
– two-sample hypothesis testing
• Single Sample Hypotheses Testing Approaches (USEPA
2013)
– T Test or Wilcoxon Signed Rank (WSR) Test
– Need at least 8 to 10 observations
23

Comparison of Predicted COC Concentration
from Stormwater to Recontamination or
Remedial Goals
• Selection of screening criteria dictated based on site
specific conditions.
• Predicted (modeled) concentrations from stormwater
runoff can be compared to screening criteria.
• Comparison allows for judgment if stormwater COCs in
sediment from stormwater are sufficient on their own to
cause a screening exceedance.
24

Summary and Conclusions
• Key Points
– Sources of COCs in urban runoff well known
– Urban stormwater associated with specific COCs and typical
concentrations
• PCBs in striping paint and architectural coatings
– Mass of COCs to the waterway as a model input
– Estimate impact of COCs in sediment bed from stormwater
25

26
Identify COCs
Measure
Concentrations
in Stormwater
Calculate COC
mass per unit
time
Determine
near field
deposition area
Model mass to
deposition area
Compare to
Cleanup Goals
or Background

Questions and Comments
27

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