Agenda Item #3
June 19,2012
Introduction
MEMORANDUM
June 15,2012
TO:
FROM:
County Council
Robert H. Drummer, Senior Legislative Attorney
Amanda Mihill, Legislative Attorney,..
~hLtU
l-
SUBJECT:
Introduction:
Bill 21-12, Erosion, Sediment Control and Stormwater
Management Coal Tar Pavement Products
Bill 21-12, Erosion, Sediment Control and Stormwater Management - Coal Tar Pavement
Products, sponsored by Councilmembers Rice, Navarro, EIrich, Riemer, and Ervin is scheduled
to be introduced on June 19, 2012. A public hearing is tentatively scheduled for July
10
at
1:30
p.m.
Bill 21-12 would prohibit the use and sale of coal tar pavement products in the County and
require enforcement by the Department of Environmental Protection. Attached on ©5 is a recent
study describing the problems caused by polycyclic aromatic hydrocarbons (PAHs) released into
the environment through the use of a coal tar pavement product. Coal tar and coal-tar pitch are
Group
1
carcinogens and the Environmental Protection Agency classifies
7 P
AH compounds as
probable human carcinogens.
This packet contains:
Bill 21-12
Legislative Request Report
American Chemical Society Study
F:\LAWISrLLSI1221 Erosion, Sediment Control-Coal Tarllntro Memo.Doc
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Bill No.
21-12
Concerning: Erosion. Sediment Control
and Stormwater Management - Coal
Tar Pavement Products
Revised: June 5,2012 Draft No.
~
_ _
Introduced:
June 19, 2012
Expires:'
December 19, 2013
Enacted: _ _ _ _ _ _ _ _ __
Executive: _ _ _ _ _ _ _ __
Effective: _ _ _ _ _ _ _ _ __
Sunset Date: --!...!N"""on""'e"---_ _ _ _ __
Ch. _ _, Laws of Mont. Co. _ __
COUNTY COUNCIL
FOR MONTGOMERY COUNTY, MARYLAND
By: Councilmembers Rice, Navarro, Eirich, Riemer, and Ervin
AN
ACT to:
(1)
(2)
(3)
(4)
prohibit the use and sale of coal tar pavement products in the County;
require enforcement by the Director of the Department of Environmental Protection;
amend the titles of Chapter 19; and
generally amend the County laws regarding water quality.
By amending the titles of Chapter 19 and adding
Montgomery County Code
Chapter 19, Erosion, Sediment Control and Storm Water Management
Article VI. GeneraL
Section 19-68
By renumbering
Montgomery County Code
Chapter 19, Erosion, Sediment Control and Storm Water Management
Article VI. GeneraL
Sections 19-68 and 19-69
Boldface
Underlining
[Single boldface brackets]
DQuble underlining
[[Double boldface brackets]]
* * *
Heading or defined term.
Added to existing law by original bill.
Deletedfrom existing law by original bill.
Added by amendment.
Deletedfrom existing law or the bill by amendment.
Existing law unaffected by hill.
The County Council for Montgomery County} Maryland approves the following Act:
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BILL No. 21-12
1
2
Sec. 1. The titles
in
Chapter 19 are amended, a new Section 19-68 is
added, and Sections 19-68 and 19-69 are renumbered as follows:
Chapter 19, Erosion, Sediment Control and [Storm Water] Stormwater
Management.
3
4
5
6
7
*
*
19-68. Coal tar pavement products.
*
*
*
Article II. [Storm Water] Stormwater Management.
*
8
9
10
11
12
W
Definitions.
As used in this Section:
Coal tar pavement product
means
~
material that contains coal tar and is
intended to cover an asphalt or concrete surface, including
or parking area.
Director
means the Director of the Department of Environmental
Protection or the Director's designee.
~
driveway
13
14
15
16
17
18
19
(hl
Use
g[
coal tar pavement products prohibited
ill
ill
A person must not use
~
coal tar pavement product in the County.
Both the property owner and the applicator have violated this
Section if
£!
coal tar pavement product is applied to an asphalt or
concrete surface on the property.
20
21
W
@
Sale.
A person must not sell or offer for sale
~
coal tar pavement product
in the County.
Enforcement.
The Director must:
22
23
ill
ill
publish
£!
list of alternative products for use on asphalt and
concrete that do not contain coal tar; and
generally enforce this Section.
24
25
26
27
[19-68] 19-69. Authority of department of environmental protection.
*
*
*
f:llaw\bills\1221 erOSion, sediment control-coal tar\biIl4.doc
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BILL
No. 21-12
28
[19-69] 19-70. Violations.
Any violation of this Chapter is a Class A violation.
However,
29
30
31
notwithstanding Section 1-19, the maximum penalty for a civil violation of Article I
is $1,000 for an initial or repeat offense. Each
day
a violation continues is a separate
offense.
32
33
*
Approved:
*
*
34
35
Roger Berliner, President, County Council
Date
36
Approved:
37
Isiah Leggett, County Executive
Date
38
This is a correct copy ofCouncil action.
39
Linda M. Lauer, Clerk ofthe Council
Date
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LEGISLATIVE REQUEST REPORT
Bill 21-12
Erosion, Sediment Control and Stormwater Management
Coal Tar Pavement Products
DESCRIPTION:
Bill
21-12 would prohibit the use of coal tar pavement products in the
County and require the Department of Environmental Protection to
enforce this law.
Coal tar and coal-tar pitch are Group 1 carcinogens and the
Environmental Protection Agency classifies 7 polycyclic aromatic
hydrocarbons (P AH) compounds as probable human carcinogens. Of
all known P AH sources, the highest concentrations are in coal tar and
related compound creosote.
To prohibit the use of coal tar pavement products.
Department of Environmental Protection
To be requested.
To be requested.
To be requested.
To be researched.
Bob Drummer, 240-777-7895
To be researched.
PROBLEM:
GOALS AND
OBJECTIVES:
COORDINATION:
FISCAL IMPACT:
ECONOMIC
IMPACT:
EVALUATION:
EXPERIENCE
ELSEWHERE:
SOURCE OF
INFORMATION:
APPLICATION
WITHIN
MUNICIPALITIES:
PENALTIES:
Class A violation.
f:\law\bills\1221 erosion, sediment control-coal tar\legislative request report,doc
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£nVIRonnu:nmL
Irsaence
,1ei:1inologg
and
E.
Spencer Williams..L
tU.S. Geological Survey, Austin, Texas 78754, United States
+Minnesota Pollution Control Agency,
st.
Paul, Minnesota 55155-4194, United States
§University of New Hampshire, Durham, New Hampshire 03856, United States
IlCity of Austin, Austin, Texas 78767, United States
.LBaylor University, Waco, Texas 76798, United States
pubs.acs,org/est
.,"'.
Coal-Tar-Based Pavement Sealcoat and PAHs: Implications for the
Environment, Human Health, and Stormwater Management
Barbara
J.
Mahler/'* Peter
C.
Van Metre/ Judy
L.
Crane,:j: Alison W. Watts,§ Mateo Scoggins, II
• INTRODUCTION
Driveways and parking lots are common features of cities,
suburbs, and small towns. Most Single-family residences in the
U.S. have paved driveways, and we encounter parking lots at
multifamily residences, schools, offices, and commercial busi­
nesses. Most people in developed countries, when outdoors,
probably spend as much time walking on pavement as on any
other type of surface.
There are differences among paved surfaces, however. Most
pavement is concrete or asphalt. The asphalt pavement of many
parking lots, driveways, and even some playgrounds in North
America is sprayed or painted with a black, shiny coating
referred to as "sealcoat," "pavement sealant," or "driveway
sealer" (Figure 1A). Sealcoat is marketed as improving
pavement appearance and increasing pavement longevity. I In
addition to making pavement black, however, one type of
commonly used pavement sealcoat contains refined coal tar and
is a potent source of polycyclic aromatic hydrocarbons
(PAHs).z-s
The contribution of pavement sealcoat to PAH
contamination of soils, lakes, and homes has only recently been
recognized.
4 - 6
Coal-Tar-Based Sealcoat: A Newly Identified Source of
PAHs.
The two primary sealcoat product types on the market
are refined coal-tar-pitch emulsion and asphalt emulsion. Coal­
tar pitch, a known (Group
1)
human carcinogen,9 is the residue
remaining after the distillation of crude coal tar (a byproduct of
the coking of coal), and contains about 200 PAH compounds.
lo
Most coal-tar-based sealcoat products consist of 20-35% coal­
tar pitch as the binder. Asphalt is the residue remaining after
the distillation of crude oil and is the binder in asphalt-based
sealcoat products. Although the two sealcoat product types are
~
ACS Publications
©
2012 American Chemical Society
similar in appearance, PAH concentrations in coal-tar-based
sealcoat are about 1000 times higher than those in asphalt­
based sealcoat
l l
(Table 1).
In
the U.S., coal-tar-based sealcoat is used primarily east of
the Continental Divide, and asphalt-based sealcoat is used
primarily west of the Continental Divide? Coal-tar-based
sealcoat also is used in Canada. 12 Geographic differences in use
in North America likely are a historical and economic artifact of
the location of most coal-tar-distillation plants near steel mills,
which historically were (and are) in the central and eastern
United States.
An
estimated 85 million gallons (320 million
liters) of coal-tar-based sealcoat are used annually in the
United States.
l l
The pavement sealcoat issue has been evolving since 2000,
when PAH concentrations were discovered to be increasing in
many urban lakes across the United States, IS even as
concentrations of other contaminants like lead,
f.0~ch10rinated
bi­
phenyls (PCBs), and DDT were decreasing.
6,1
This was an
apparent reversal from earlier reports that PAH concentrations in
the U.S. were decreasing in
re~onse
to reduced emissions from
power plants and industries.IS,1 The earlier studies, however, had
focused on lakes in undeveloped watersheds, whereas the upward
trends in PAHs were in lakes in urban and suburban watersheds.
This
meant, first, that reductions in
PAH
emissions caused by
changes in home-heating and power-generation technology had
been eclipsed in urban areas by some other urban source of
PAHs,lS and second, that this other source
was
specific to urban
and suburban areas.
A breakthrough in understanding urban sources of PAHs
came in 2003, when staff with the City of Austin, TX, noted
elevated PAH concentrations (1:PAH
l6
>
1000 mg/kg)
in some sediment samples collected from small tributaries
and drainages in largely residential areas.
20
Concentrations of
P
AHs
this high are typical of contaminated soils at some
manufactured gas plant Superfund sites/ I but cannot be
accounted for by common urban sources (e.g., tire wear, vehicle
emissions, asphalt)? City of Austin staff connected the dots and
hypotheSized that the source of the elevated PAHs was particles
eroded from parking lots that were coated with coal-tar-based
sealcoat,z2 Since that time, an understanding has emerged of
relations between coal-tar-based pavement sealcoat and PAHs
in the environment.
Published:
January
24, 2012
dx,doi.orgl1 0.1 021
les203699x
I
Environ, Sci, Technol,
2012,46.3039-3045
3039
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Figure
1.
PARs from coal-tar-based pavement sealcoat are transported by different pathways to various environmental compartments. Once dry, the
sealcoat product (A), which contains high concentrations of PARs, is abraded into a powder and becomes part of the dust on the pavement (B).
That dust is transported by storm runoff
(C)
to stormwater management devices CD) or to receiving stream.s and lakes
(£).
:arlting lot dust also
adheres to tires (F) that track it onto unsealed pavement, and wind and runoff transport the dust to nearby soils (G). Dust particles
~so
are
tr~cked
on shoes into residences, where they become incorporated into house dust (H). Volatile PARs in coal-tar-based sealcoat are released Into the aIr
(r).
PAR concentrations associated with each compartment and literature sources are provided in Table
1.
WHAT ARE POLYCYCLIC
ARO~IATIC
HYDRO­
CARBONS CPABS)? PAHs are a large group of
organic compounds composed of two or. more fused
benzene rings arranged in various configurations. Those
with a low molecular weight (two or three benzene
rings) tend to be more volatile, soluble, and biodegrad­
able than those with a higher molecular weight (four or
more benzene rings). PAHs occur naturally in coal and
petroleum products and are formed by the incomplete
combustion of organiC matter, from fossil fuels to wood
to cigarettes. PAHs have many urban sources, including
used motor oil, automobile exhaust, industrial atmos­
pheric emissions, tire particles, and asphalt.
13,14
PAHs
always occur as a mixture of different PAH compounds,
and are ubiquitous in the urban environment. Of
all
known PAH sources, the highest concentrations are in
coal tar and the related compound creosote. Most
laboratories analyze only a subset of PAHs, and
concentrations of total PAHs are reported as the sum
of the subset analyzed as described in Table
1.
Migration of PAHs from Sealcoated Surfaces into the
Environment.
Sealco~t
doesn't remain on the pavement sur­
face indefinitely, and different applicators recommend reappli­
cation from every 1 to 2 years (e.g., ref 23) to every 3 to 5 years
(e.g., ref 24). Tires and snowplows, in particular, abrade the
friable sealcoat surface into fine particles.s,ll The overall annual
loss of sealcoat from parking lots in a
warm
climate is about 2.4%
of total sealcoat applied, with wear being most rapid (about
5% per year) in driving areas.
l1
Higher wear rates have been
noted in a cold-weather climate? The mobilized sealcoat particles
and associated PAHs are transported to various environmental
compartments (Figure I, Table 1).
The first compartment is the dust on the pavement surface
itself, generated as the sealcoat is abraded from the surface
3040
(Figure IB). Concentrations ofPAHs in fine particles (dust) on
pavement with coal-tar-based sealcoat are hundreds of times
higher than those in dust on concrete pavement or on asphalt
pavement that is unsealed or that has asphalt-
b
ased sealcoat
3-5
(Table 1). PAHs in dust on sealcoated pavement in the central
and eastern U.S. are about 1000 times higher than in dust on
seal coated pavement in the western U.S., supporting anecdotal
reports of geographic differences in product use
3
(Figure 2).
Stormwater runoff transports abraded seal coat particles off
sealed pavement (Figure lC, Table 1). The PAH concentration
measured in particles in runoff from parking lots with coal­
tar-based sealcoat (3500 mg/kg) was 65 times higher on
average than the concentration in particles in runoff from
unsealed asphalt and cement lots.
2
Concentrations in unfiltered
stormwater runoff from coal-tar-sealcoated pavement are
particularly elevated during the months follOwing sealcoat
application. The mean kPAH
I6
in stormwater runoff from a
coal-tar-sealcoated parking lot during the 3 months following
sealcoat application was 1357 Itg/L and the 3-month
rnea~
during the follOwing two years ranged from 17 to 116 flg/L.
This relatively elevated concentration persists for years-the
median kPAH
18
in stormwater runoff from a parking lot in
Madison, WI, 5 years after the last application of coal-tar-based
sealcoat,
was
52 Itg/L.
25
That concentration is about 10 times
higher than that in runoff from a mixed-use strip mall, arterial
street, and unsealed parking lot (4.8-5.7 flg/L), more than 20
times higher than in runoff from a minor arterial street and a
commercial rooftop
(1.8~
2.4 fl.g/L), and about 1000 times
~~her
than in runoff from a reSidentIal feeder street (0.05 Ilg/L).
In many communities, the first stop for stormwater runoff is
a stormwater-retention pond or other stormwater-management
device (Figure ID), where suspended sediment and associated
contaminants settle out. Stormwater ponds are designed to
efficiently collect sediment-associated contaminants, which
creates an unintended problem for many municipalities
becau~e
It:)
PAHs accumulate in pond sediment. In 5 of 10 ponds sampled
the Minneapolis-St. Paul, MN, metropolitan area, concentrations
ID&
dx.doLorgl10.1021/e5203699x I
Environ.
Sci.
Technol.
2012, 46.
3039-3045
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Table 1. Concentrations of PAHs as Reported in the Literature for Environmental Compartments Shown in Figure 1, and
Definitions of PAH Summations Used
enwoumental
PAH COncentration
.
"PAHconcentration:(m~di.anor
.
(m!!diart or mean)
inc6a1·
mean)
masphalt
seaiC6at,
affected
tar-based sealcoat
or
affected
medium
seaicoat products
pa~ment
compartment
~·mediumJ.or ~odat.;d
with unsealed
(Figure 1)
A
B
dust
....
pavemellt
66000
2200
4760
50
11
:EPAH I6
:EPAH'l
:EPAH I6
EPAH 16
:EPAH 12
EPAH'6
:EPAH Is
EPAH 16
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Jlg/L
Jlg/L
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
ng/m
3
11,22
9
<1
54
2
3
4
5
2
7
25
5
685
c
D
E
F
runoff,
particles
runoff,
unfiltered watei'
stormwater-management-device
sediment
lake sediment"
tires
soild
settled house dust
air
(0.03
m from pavement),
3-8
years after sealing
3500
71
~
646
33
1380
5
2
0.4
3
2
6
5
5
4
28
G
H
105
129
1320
138
5
66
26
air (1.28
m from pavement),
3-8
years after sealing
air (0.03
m
from
pavement), 1.6 h
after sealing
air (1.28
m from pavement),
1.6 h
after sealing
28
29
29
297000
66
26
5680
"':EPAH
12
is
the sum of concentrations of the 12 parent PAH (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, .anthracene,
fluoranthene, pyrene, benz[
a]
anthracene, chrysene, benzo[a ]pyrene, and dibenz[a,h] anthracene ), which are those PAHs used in computation of the
probable effects concentration (PEC) sediment-quality guideline,41 less 2-methylnaphthalene. :EPAH
I6
is the sum of the concentrations of the 16
priority pollutants identified by the
u.s.
Environmental Protection Agency,42 equal to the sum of :EPAH 12 and concentrations of
benzo[b]fluoranthene, benzo[ghi]perylene, benzo[k]fluoranthene, and indeno[l,2,3-cd]pyrene. :EPAH
ls
is equal to :EPAH 16 plus concentrations
of I-methylnaphthalene and 2-methylnaphthalene. :EPAH
CMB
is the sum of concentrations of phenanthrene, anthracene, fluoranthene, pyrene,
benz[a]anthracene, chrysene, benzo[a]pyrene, benzo[b ]fluoranthene, benzo[ghi]perylene, benzo[k]fluoranthene, indeno[ l,2,3-cd]pyrene, and
benzo[e]pyrene. :EPAH
g
is the sum of concentrations of phenanthrene, anthracene, 4,5-methylphenanthrene, 1-methylphenanthrene, fluoranthene,
pyrene, chrysene, and benzo[b ]fluoranthene. On the basis of PAH data from primarily combustion sources presented in Mahler et al/ :EPAH 12 is
about 70-75% of:EPAH'6' :EPAH
ls
is similar to :EPAHu)J as the additional compounds in the summation either are not detected or are detected at
very low concentrations.
2•25
b
Collected> 3 months after sealcoat application. cMeans for urban lakes with>70% PAH from sealcoat and 0-20% from
sealcoat. dConcentration in soil adjacent to a sealed parking lot.
ashington, D.C.
Figure 2. PAHs in dust swept from sealcoated parking lots show a
striking geographic difference. PAH concentrations in dust from
parking lots in central and eastern
U.s.
cities, where coal-tar-based
sealcoat is commonly used, are about 1000 times higher than in the
western
U.S.,
where asphalt-based sealcoat is more commonly used.
Concentrations are the sum of 12 PAHs (:EPAH
12),
in mg/kg. (Figure
adapted from ref 3, Figures 1 and 2).
of PARs in sediment exceeded Minnesota's Level 2 Soil
Reference Value of 3 mg/kg benzo[a}pyrene
e~uivalents
(BaPeq), greatly increasing the cost for disposal.
2
Even a
small amount of sealcoated pavement can be the dominant source
of PARs to sediment that collects in stonnwater-management
3041
devices, as demonstrated at the University ot New Hampshire
Stonnwater Center_
S
Sediment collected from a stonnwater­
management device receiving runoff from a parking lot with
coal-tar-based sealcoat contained !:PAH 16 of393-1180 mg/kgj
sediment in devices receiving mixed runoff (4% sealed pavement
and 96% unsealed pavement) contained 61-638 mg/kg !:PAR
l
6i
and sediment in a device in the center of an adjacent unsealed lot
contained less than 4 mg/kg !:PAR16.5
Some sealcoat particles that are not trapped by stonnwater
ponds or other collection devices are transported down streams
and rivers to lakes, where they are deposited in lake sediment
(Figure IE). Do the PAHs associated with the particles
constitute a majority of PARs in urban lake sediments, and
might coal-tar-based sealcoat account for many of the upward
trends in PARs reported by Van Metre et al.?15 An initial
indication comes from a comparison of PAH ratios, or
"fingerprints", of the dust collected from parking lots in nine
U.S. cities to that of PARs in sediment from lakes in the same
watersheds':' In the central and eastern U.S., PAH fmgerprints
of lake sediment and dust from sealcoated parking lots were
similar, and were different from fmgerprints of lake sediment
and dust in the western U.S., reflecting regional differences
T-;1
in sealcoat product type used. A more sophisticated source0
apportionment method-a statistical approach that quantifies
dx.doi.orgll0.l0211es203699xl
Environ. Sci. Technol.
2012.46,3039-3045
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"iiiiN
PAHs measured in pavement dust in the western U.S. (Figure 2),
where coal-tar-based sealcoat is not commonly used.
In
addition to contaminating stormwater, sediment, soil, and
house dust, PAHs from coal-tar-based sealcoat contaminate air
(Figure 1I). Several of the lower molecular weight PAHs
in
coal-tar-based sealcoat are volatile, which is why sealed parking
lots and driveways frequently give off a strong smell. A recent
studi
8
reported that the
flux
of l:PAH
g
from in-use parking
lots with coal-tar-based sealcoat of various ages (mostly more
than 3 years old) was 60 times higher than that from unsealed
pavement on average.
A
second studi
9
reported that l:PAH
g
in
air just after sealcoat application was hundreds to thousands of
times higher than that above unsealed parking lots (Table
1),
and that one-quarter to one-half of the PAHs in the applied
sealcoat were lost to the atmosphere during the first 16 days
follOwing application. A mass balance indicated that l:PAH
g
emissions from new applications of coal-tar-based sealant each
year are larger than annual vehicle emissions of
P
AHs for the
U.S.
29
Biological Concerns.
The detrimental effects of PAHs on
30
terrestrial and aquatic ecosystems are well documented. For
example, when fish are exposed to PAHs, they exhibit chronic
effects, including
fin
erosion, liver abnormalities, cataracts, skin
tumors, and immune system impairments leading to increased
susceptibility to disease. 31 When benthic macroinvertebrates­
insects and other organisms that live at the bottom of rivers and
lakes and that make up the base of the aquatic food chain­
are exposed to PAHs, they are susceptible to a number of
detrimental effects, including inhibited reproduction, delayed
emergence, sediment avoidance, and mortality.31 The most
important mechanism by which acute effects occur in benthic
invertebrates is a nonspecific narcosis-like mode of action that
results in the degradation of cell membranes.
32
Ultraviolet
(UV) radiation greatly increases the toxicity of PAHs in a wide
variety of aquatic organisms.
33­ 36
As
the importance of coal-tar-based sealcoat as a source of
PAHs has emerged, several studies have looked at potential
biolOgical effects of this particular source of PAHs. When
sediment was spiked with coal-tar-based sealcoat to provide a
range of environmentally relevant PAH concentrations, frogs
(Xenopus laevis)
had stunted growth or delayed development at
30
mg/kg kPAH
16,
and complete mortality occurred at the
highest treatment of
300
mg/kg l:PAH
16•37
Salamanders
(Ambystoma maculatum)
and newts
(Notophthalmus viridescens)
exposed to sediment contaminated with coal-tar-based sealcoat
at PAH concentrations similar to the highest treatment in
the frog study had stunted growth, difficulty swimming or
righting themselves, and liver problems.38
,39
These effects were
magnified by the addition of UV light. 38 At the community
level, macroinvertebrate communities exposed to sediment
spiked with coal-tar-based sealcoat had significant decreases in
species abundance and richness at l:PAH
I6
concentrations
exceeding
300
mg/kg.40 Similarly, in a study of urban streams,
aquatic invertebrate communities downstream from parking
lots with coal-tar-based sealcoat suffered losses of abundance
and diversity along a gradient of increasing total PAH con­
centration, starting near the
l:PAH~2 ~robable
effects concen­
tration (PEC) value of
22.8
mg/kg. o.
I
These studies demon­
strate that PAHs in sediment contaminated by coal-tar-based
sealcoat are bioavailable and that environmentally relevant con­
centrations adversely affect amphibians and benthic commun-
k1>\
ities, two robust indicators of aquatic ecosystem health. The
~
finding of adverse biological effects to biota when exposed to
3042
dx.doLorgI10.1021Ies203699xi
Environ.
Sci.
Technof.
2012.46.3039-3045
the contribution of sources with known PAH profiles to an
environmental receptor-was used to quantify the contribution
of identified urban PAH sources to PAHs in bed sediment in
40
U.S. urban lakes.
6
Coal-tar-based sealcoat was estimated to
contribute about one-half of the PAHs in the lake sediment,
when averaged across the
40
lakesj vehicle-related sources and
coal combustion also were important contributors. PAH
concentrations in lake sediment and the proportion contributed
from coal-tar-based sealcoat were greater in the central and
eastern U.S. than in the western U.S. Using sediment cores,
trends in PAHs were investigated for eight urban lakesj of the
six with significant upward trends, source apportionment
indicated that coal-tar-based sealcoat was the cause of the
trend in all six of them.
Turning our attention back to sealed pavement, dust from
pavement with coal-tar-based sealcoat contaminates nearby
unsealed pavement, with concentrations decreaSing with
distance from the sealed pavement.5 A petrographic analysis
of dust from unsealed pavement in Fort Worth, TX, found that
coal-tar pitch was the dominant
(92%)
source of PAHs in the
dust. s Particles are transported by adhesion to vehicle tires and
by wind from sealed to unsealed surfaces-l:PAH
16
in particles
swept from tires driven over sealed lots were
400
times higher
than in particles swept from tires driven over unsealed lots
5
(Table I, Figure IF). Transport of abraded coal-tar-based
sealcoat particles by wind and tires might be one reason why
PAH concentrations in dust from unsealed parking lots in
the central and eastern U.S. (median l:PAH
12
27
mg/kg), where
coal-tar-based sealcoat is predOminantly used, are Significantly
higher than those in dust from unsealed parking lots in the
western U.S. (median l:PAH
12
0.8
mg/kg), where the asphalt­
based product is predominantly used.
3
PAHs in particles abraded from coal-tar-based sealcoat also
are transported by wind, runoff, and snow removal to nearby
soils (Table I, Figure IG). l:PAH
I6
in surface soil adjacent to
coal-tar-sealed lots at the University of New Hampshire was as
high as 411 mg/kg, and concentrations decreased with distance
from the sealed lot to less than 10 mg/kg.5 The highest
concentrations were measured in areas where snow was piled
adjacent to the lots during the winter months-snowplows
were scraping the sealcoat off with the snow. PAHs in surface
soils from commercial areas in Fort Worth, TX, were
dominantly
(88%)
from coal-tar pitch.s
PAHs from pavement sealed with coal-tar-based sealcoat can
contaminate the indoor environment (Figure IH) as well as the
outdoor environment. In a study in Austin, TX, apartments
with parking lots with coal-tar-based sealcoat had l:PAH
I6
in
house dust that was
25
times higher, on average, than l:PAH
I6
in house dust from apartments with parking lots with other
surface
t;JI:es
(concrete, unsealed asphalt, or asphalt-based
sealcoat) (Table
1).
The presence or absence of coal-tar-based
sealcoat on the apartment complex parking lot was strongly
correlated with PAH concentrations in house dust. Although
tobacco smoking, candle and incense burning, and barbecue
and fireplace use have been suggested to affect PAH
concentrations in house dust, Mahler et al.
4
found no relation
between any of these and PAH concentrations in the house
dust. Concentrations of individual PAHs in house dust
collected from apartments in Austin adjacent to pavement
with coal-tar-sealcoated parking lots were about
140
times
higher than those measured in a study of house dust in
California.
27
Lower concentrations of PAHs in house dust in
California are consistent with the very low concentrations of
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Environmental Science & Technology
',,!!IIM
of Austin, TX, in 2006.
47
As
ofJanuary 2012, 15 municipalities
and two counties in four states (Minnesota, New York, Texas,
and Wisconsin), the District of Columbia, and the State of
Washington had enacted some type of ban, affecting nearly 10.4
million people.
4s
Other local and state jurisdictions have used
voluntary or limited-use restrictions for certain groups (e.g., city
48
government) to discourage the use of coal-tar-based sealcoat.
Minnesota, in particular, has been actively engaged in this issue
after municipalities contacted state agencies and the Minnesota
Legislature for assistance addressing PAH-contaminated storm­
water pond sediment. 49 Costs for disposing of this sediment
could reach $1 billion
if
PAHs in sediment in just 10% of the
estimated 20 000 municipal stormwater ponds in the Minneap­
olis-St. Paul, MN, metropolitan area exceed Minnesota's Level 2
human-health risk-based Soil Reference Value of 3 mg/kg
BaPeq50 (Donald Berger, Minnesota Pollution Control Agency,
written communication, 2011). The Minnesota Legislature passed
a bill in 2009 that provides small grants to local governments for
use in treating or disposing of contaminated sediment in storm­
water ponds, provided that the
~ovemments
restrict the use of
undiluted coal-tar-based sealcoat. 9
As
of January 2012, 13 muni­
cipalities had passed ordinances and three municipalities have
received grants for remediation of stormwater ponds.
Several national and regional hardware and home-improvement
retailers have voluntarily ceased selIing coal-tar-based driveway­
sealer products.
48
Some private applicators have chosen to use
only asphalt-based sealcoat (e.g., refs 51,52). Many profeSSional
sealcoating companies in areas unaffected by bans or restric­
tions use coal-tar-based sealcoat, however, and coal-tar-based
sealcoat products are readily available online for purchase by
homeowners.
No action has been taken at a federal level to restrict the use
of coal-tar-based sealcoat. Coke product residues, such as coal
tar, are not classified as hazardous waste under the Resource
53
Conservation and Recovery Act
if
the product is recycled.
This exemption allows coal-tar pitch to be used in the
production of aluminum (-95% of use), commercial carbon,
built-up roofing, and pavement sealcoat.
54
Because PAHs are a ubiquitous and persistent class of urban
contaminants, a decade or more might be reqUired to assess .the
effectiveness of bans, restrictions, and/or changes in the retail
aVailability of coal-tar-based sealcoat on reducing PAH
concentrations in urban water bodies. Research on trends in
the occurrence of PCBs and DDTs supports this concern.
FollOwing national bans on use of PCBs and DDT in the 19705,
it was 10-15 years before concentrations in lakes and reservoirs
decreased by one_hal£17,5S Unlike these chemicals, all sources of
PAHs in urban watersheds will not be eliminated by banning
coal-tar-based sealcoat. However, reductions in PAH loads over
time might be sufficient to prOvide more options for disposal of
dredged material from stormwater ponds and navigation
channels and reduce risk to terrestrial and aquatic ecosystems
and human health.
sediment with PAH concentrations near the PEC has wide­
spread relevance: Of the 40 U.S. urban lakes investigated by
Van Metre and Mahler/ sediment in the nine lakes with the
greatest mass loading of PAHs from coal-tar-based sealcoat had
concentrations of PAHs that exceeded the PEe.
Human-Health Concerns.
Coal tar and coal-tar pitch are
listed as Group 1 (carcinogenic to humans) carcinogens,9 and
the U.S. EPA currently classifies seven PAH compounds as
probable human carcinogens (Group B2): benz[a]anthracene,
benzo[aJpyrene, benzo[b Jfluoranthene, benzo[kJt1uoranthene,
chrysene, dibenz[a,h Janthracene, and indeno
[I,2,3-cdJ­
pyrene.
42
Coal tar itself is a powerful mutagen: The muta­
genicity index for coal tar is about 1000 times that of asphalt
cements.
43
However, although coal-tar-based sealcoat has been
on the market since at least 1960/ little has been published
to date about the contribution of the sealcoat to PAH expo­
sures and the associated potential for adverse human-health
outcomes.
The elevated concentrations of PAHs in house dust, soil, air,
water, and sediment associated with coal-tar-based sealcoat
raise the possibility of several complete exposure pathways for
humans. Incidental ingestion of house dust and soil is
particularly relevant for small children, who
~ut
their hands
and objects into their mouths. A recent study reported that
children living in homes adjacent to pavement with coal­
tar-based sealcoat likely are exposed to about 14-fold higher
doses of PAHs through ingestion of house dust than are
children living in residences adjacent to unsealed pavement,
and that exposure from ingestion of PAH-contaminated house
dust is estimated to be more than double that from diet, even
under conservative assumptions. Ingestion of contaminated soil
is another way that children might be exposed to PAHs from
coal-tar-based sealcoat, particularly given that ingestion rates of
soil typically exceed those of house dust.
45
Incidental ingestion
of dust directly from sealed pavement also might be important,
because the extremely high concentrations of PAHs measured
in these materials (Table 1) could translate to substantial doses
from miniscule exposures. On a long-term basis, nondietary
ingestion of PAH-contaminated house dust and soil likely are
the most important routes of exposure, but a complete human­
health risk analysis is required before the cancer risk associated
with ingestion of these media can be quantified.
Other routes of exposure to coal-tar-based sealcoat, in addition
to ingestion, might have implications for human health. Relatively
high acute exposures might occur from inhalation of wind-blown
particles or fumes that volatilize from sealed parking lots,
especially during sealcoat application. Sealcoat applicators, in
particular, might be subject to substantial inhalation exposures,
but such exposures have not yet been characterized. Other
potential routes include
skin
contact with sealcoat and abraded
sealeoat particles and contaminated soil, sediment, dust, and
water. Such exposures likely would be relatively infrequent and
short-term. However, PAHs are readily absorbed through the
skin,4¢ and circumstances that increase the frequency or
magnitude of exposure events, such as daily activity on pavement
treated with coal-tar-based sealcoat, might be associated with
increased cancer
risk.
Regulatory and Retail Actions.
Research to date, as
documented here, prOvides a compelling weight-of-evidence
that coal-tar-based sealcoat products are an important source of
PAHs to our environment. A patchwork of actions has been
taken to either ban or restrict the use of coal-tar-based sealcoat
in the United States. The first ban was implemented by the City
3043
II AUTHOR INFORMATION
Corresponding Author
*E-mail: bjmahler@lusgs.gov.
Notes
The authors declare no competing financial interest.
dx.doi.orgll0.1011Iesl03699x
I
Environ. Sci. Technol. 2011,
46, 3039-3045
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Environmental Science & Technology
ImlliN
(20) Scoggins,
M.;
McClintock, N.; Gosselink,
L.;
Bryer, P.
Occurrence of polycyclic aromatic hydrocarbons below coal-tar-sealed
parking lots and effects on stream benthic macro invertebrate
communities.
J.
N.
Am. Benthol. Soc.
2007, 26 (4), 694-707.
(21) Haeseler, F.; Blancher, D.; Druelle, V.; Werner, P.; Vandecasteel,
].-P. Ecotoxicological assessment of soils of former manufactured gas
plant sites: Bioremediation potential and pollutant mobility.
Environ.
Sci. Technol.
1999, 33 (24), 4379-4384.
(22)
PARs in Austin, Texas, Sediments and Coal-Tar Based Pavement
Sealants, Polycyclic Aromatic Hydrocarbons; City
of Austin Watershed
Protection and Development Review Department: Austin, TX, 200S;
http://www.ci.austin.tx.us/watershed/ downloads / coal tar_draftJah_
study.pdf.
(23) The Blacktop Guy - FAQ, http://www.blacktopguy.com/faq.
php#_13.
(24) A·Line Asphalt Products Frequently Asked Questions. http://
www.alineasphaltproducts.com/faq.html.
(2S) Selbig, W. R
Concentrations of Polycyclic Aromatic Hydrocarbons
(PARs)
in
Urban Storm water, Madison, Wisconsin,
2005-08;
Open File
Report 2009-1077; U.S. Geological Survey: Denver, CO, 2009;
http://pubs.usgs.gov/of/2009/1077/pdflofr20091077.pdf.
(26) Polta, R; Balogh, S.; Craft-Reardon,
A
Characterization of
stormwater pond sediments. Final project report,
EQA Report 06-S72;
Environmental Quality Assurance Department, Metropolitan
Council Environmental Services: St. Paul, MN, 2006; http://
www.metrocouncil.org/Environment/sediment/FinalReport.pdf.
(27) Whitehead, T.; Metayer, C; Gunier,
R.
B.; Ward, M. H.;
Nishioka, M. G.; Buffler, P.; Rappaport, S.
M.
Determinants of
polycyclic aromatic hydrocarbon levels in house dust.
J.
Expo. Sci. Env.
Epid.
2011,21 (March/April), 123·132.
(28) Van Metre, P. C; Majewski, M. S.; Mahler, R
].i
Foreman,
W. T.; Braun, C.
L.;
Wuson, J. T.; Burbank, T. Volatilization of poly­
cyclic aromatic hydrocarbons from coal-tar-sealed pavement. Chemo­
sphere 2012, http://dx.doi.org/lO.lO 16/j.chemosphere.20 11.12.072.
(29) Van Metre, P. C; Majewski, M. S.; Mahler,
B.
J.;
Foreman,
W. T.; Braun, C
L.;
Wilson, J. T.; Burbank, T. PAH volatilization
follOwing application of coal-tar-based pavement sealant.
Atmos.
Environ.
2012, http://dx.doi.org/1O.1016/j.atmosenv.2012.01.036.
(30) Douben, P. E. T.
PARs: An Ecotoxicological Perspective;
John
Wiley & Sons Ltd.: West Sussex, England, 2003.
(31) Toxicological profile for polycyclic aromatic hydrocarbons;
http://www.atsdr.cdc.gov/toxprofiles/ tp.asp ?id= 122&tid=2S.
(32) Van Brummelen, T.
Ai
et al. Bioavailability and ecotoxicity of
PAHs. In
PARs and Related Compounds. The Handbook of Environ­
mental Chemistry;
Neilson,
A;
Hutzinger,
0.,
Eds.i Springer Verlag:
Berlin, Germany, 1998; Vo!' 3, part
J.
(33) Ireland, D. S.; Burton, G.
A
Jr.; Hess, G. G. In situ toxicity
evaluations of turbidity and photoinduction of polycyclic aromatic
hydrocarbons.
Environ. Toxicol. Chern.
1996, 15, S74-S81.
(34) Diamond, S.
A;
Milroy, N.
J.;
Mattson, V. R; Heinis, L.
J.;
Mount, D. R Photoactivated toxicity in amphipods collected from
polycyclic aromatic hydrocarbon,contaminated sites.
Environ. ToxieoL
Chern.
2003, 22, 27S2-2760.
(3S) Diamond, S.
A;
Mount, D. R; Burkhard,
L.
P.; Ankley, G.
T.;
Makynen, E.
A;
Leonard, E. N. Effect of irradiance spectra on the
photOinduced toxicity of three polycyclic aromatic hydrocarbons.
Environ. Toxicol. Chern.
2000, 19, 1389-1396.
(36) Ankley, G. T.; et al. Assessing risks from photoactivated toxicity
ofPAHs to aquatic organisms. In
PARs: An Ecotoxicological Perspectivej
Douben, P. E. T., Ed.; John Wiley
&
Sons Ltd.: West Sussex, England,
2003i pp 27S-296.
(37) Bryer, P.].; Elliott,]. N.; Willingham, E.J. The effects of coal tar
based pavement sealer on amphibian development and metamorpho-
.
sis.
Ecotoxicology
2006, 15, 241-247.
(38) Bommarito, T.; Sparling, D.
W.j
Halbrook, R S. Toxicity o{!/
coal-tar pavement sealants and ultraviolet radiation to
Ambystoma
maculatum. Ecotoxicology
2010, 19, 1147-11S6.
3044
dx.doi.orgl1 0.1021
les203699x
I
Environ. Sci. Technol.
2012. 46. 3039-3045
REFERENCES
(1)
Dubey, G.
Understanding how sealcoating works
...
and how it can
save you money;
http://pavementpro.org/understanding.htm.
(2) Mahler,
B.].;
Van Metre, P. C; Bashara, T.
J.;
Wilson, ]. T.;
Johns. D. A. Parking lot sealcoat: An unrecognized source of urban
polycyclic aromatic hydrocarbons.
Environ. Sci. TechnoL
2005, 39,
SS60-SS66.
(3) Van Metre, P. C; Mahler,
B.].i
Wilson,
J.
T. PAHs underfoot;
Contaminated dust from coal-tar sealcoated pavement is widespread in
the United States.
Environ. Sci. Technol.
2009,43 (I), 20-2S.
(4) Mahler, R
J.;
Van Metre, P. C; Wilson,
J.
T.; Musgrove,
M.;
Burbank, T.
L.;
Ennis, T. E.; Bashara, T.
J.
Coal-tar-based parking lot
sealcoat: An unrecognized source of PAH to settled house dust.
Environ. Sci. Techno!.
2010, 44, 894-900.
(S)
Polycyclic aromatic hydrocarbons released from sealcoated parking
lots A controlled field experiment to determine if sealcoat is a significant
source of PARs in the environment;
University of New Hampshire
Stormwater .Center; Durham, NH, 2010.
(6) Van Metre, P. C; Mahler, B. J. Contribution of PAHs from coal­
tar pavement sealcoat and other sources to 40 U.S. lakes.
Sci. Total
Environ.
2010,
409,
334-344.
(7) Watts,
A
W.; Ballestero, T. P.; Roseen, R
M.;
Houle,
J.
P.
Polycyclic aromatic hydrocarbons in stormwater runoff from seal­
coated pavements.
Environ. Sci. Technol.
2010, 44, 8849-88S4.
(8) Yang, Y.; Van Metre, P. Ci Mahler,
B.
J.;
Wilson,
J.
T.; Ligouis,
B.; Razzaque,
M.;
Schaeffer, C; Werth, C The influence of coal-tar
sealcoat imd other carbonaceous materials on polycyclic aromatic
hydrocarbon loading in an urban watershed.
Environ. Sci. Technol.
2010,44 (23).1217-1233.
(9) Monographs on the Evaluation of Carcinogenic Risks to Humans
Supplement
7:
Coal-Tar Pitches (Group
1); International Agency for
Research on Cancer: Lyon, France, 1987; http://monographs.iarc.fr/
ENG/Monographs/suppI7/SuppI7-S7.pdf.
(10) TOXicological profile for wood creosote, coal tar creosote, coal tar,
coal tar pitch, and coal tar pitch volatiles;
U.S. Department of Health
and Human Services, Agency for Toxic Substances and Disease
Registry: Atlanta, GA, September 2002; http://www.atsdr.cdc.gov/
ToxProfiles/ tp8S.pdf.
(ll)
Scoggins,
M.i
Ennis, T.; Parker, N.; Herrington, C A
photographic method for estimating wear of coal tar sealcoat from
parking lots.
Environ. Sci. Technol.
2009, 43 (13), 4909-4914.
(12) Reconnaissance study ofcoal tar sealcoat application
in
Toronto and
an estimate of related PAR emissions;
Diamond Environmental Group,
Department of Geography and Department of Chemical Engineering,
University of Toronto: Toronto, ON, 2011. Prepared for Environment
Canada.
(13) Rogge, W. F.; Hildemann,
L.
M.;
Mazurek, M.
Aj
Cass, G. R;
Simoneit, B. R T. Sources of fine organic aerosol. 3. Road dust, tire
debris, and organometallic brake lining dust: roads as sources and
sinks.
Environ. Sci. TechnoL
1993, 27 (9), 1892-1904.
(14) Yunker, M. R; Macdonald, R W.; Vingarzan, R; Mitchell,
R H.; Goyette, D.; Sylvestre, S. PAHs in the Fraser River basin: A
critical appraisal of PAH ratios as indicators of PAH source and
composition.
Org. Geochem.
2002, 33, 489-S IS.
(IS) Van Metre, P. C; Mahler, B.].; Furiong, E. T. Urban sprawl
leaves its PAH signature.
Environ. Sci. TechnoL
2000, 34, 4064-4070.
(16) Mahler, B.].! Van Metre, P. C; Callender, E. Trends in metals
in urban and reference lake sediments across the United States, 1970­
2001. Environ. Toxicol. Chern.
2006,25 (7), 1698-1709.
(17) Van Metre, P. C; Mahler, B.J. Trends in hydrophobic organic
contaminants in urban and reference lake sediments across the
United States, 1970-2001.
Enl1iron. Sci. Techno!.
2005, 39, SS67­
SS74.
(18) Furlong, E. T.; Cessar,
L.
Ri Hites, R
A
Accumulation of
polycyclic aromatic hydrocarbons in acid sensitive lakes.
Geochem.
Cosmochim. Acta
1987, 51
(ll),
296S-297S.
(19) Gschwend, P.
M.;
Hites, R
A
Fluxes of polycyclic aromatic
hydrocarbons to marine and lacustrine sediments in the northeastern
United States.
Geochem. Cosmochim. Acta
1981, 45 (12), 23S9-2367.
0{;l
 PDF to HTML - Convert PDF files to HTML files
Environmental Science
&
Technology
(39) Bommarito, T.; Sparling, D. W.; Halbrook,
R.
S. Toxicity of
coal-tar and asphalt sealants to eastern newts,
Notophthalmus
viridescens. Chemosphere
2010, 81 (2), 187-193.
(40) Bryer, P.
J.;
Scoggins, M.; McClintock, N.
L.
Coal-tar based
pavement sealant toxicity to freshwater macroinvertebrates.
Environ.
Pollut.
2009, 158 (5), 1932-1937.
(41) MacDonald, D. D.; Ingersoll,
C.
G.;
Berger, T.
A
Development
and evaluation of consensus-based sediment quality guidelines for fresh­
water ecosystems.
Arch. Environ. Contamin. ToxicoL
2000,39, 20-3!.
(42) Integrated Risk Infonnation System (IRIS); http://cfpub.epa.
gov
I
nceal irisl index.cfin.
(43) Detection of coal tar materials in asphalt pavements using
chemical and biological methods; http://www.asphaltinstitute.org/
public/engineering/PDFs/Environmental/Detection_ Coal_Tar_
Materials_Asphalt_Pavements_Usin!L Chern_ Bio_ Methods.pd£
(44) Williams, E. S.; Mahler, B.
J.;
Van Metre, P. C. Coal-tar
pavement sealants might substantially increase children's PAH
exposures.
Environ. Pollut.
2012, http://dx.doLorgi 10.10
161
j.envpol.
2012.0!.
(45)
Exposure Factors Handbook:
2011
ed.;
EPA!600!R-090/052F;
U.S. Environmental Protection Agency: Washington, D.C., 2011;
http://www.epa.gov
I
nceal
elh/pdfsl
elh-complete.pd£
(46) Roy, T.
Ai
Krueger,
A
J.;
Taylor, B. B.; Mauro, D. M.;
Goldstein,
L.
S. Studies estimating the dermal bioavailability of
polynuclear aromatic hydrocarbons from manufactured gas plant tar­
contaminated soils.
Environ. Sci. Technol.
1998, 32 (20), 3113-3117.
(47)
An ordinance amending the
city
code to add a new Chapter
6-6
relating to coal tar pavement products, creating offenses, and prOViding
penalties,
Ordinance No. 2005117·070, 2005; http://www.ci.austin.tx.
us!
edimsl
document.cfin ?id=94225.
(48) Status of actions regarding use of coal tar-based sealants;
http://
www.pca.state.mn.us/index.php/view-document.html?gid=16180.
(49) Crane,
J.
L.;
Grosenheider,
Kj
Wilson, C.
B.
Contamination of
Stormwater Pond Sediments
by
Polycyclic Aromatic Hydrocarbons
(p
AHs)
in Minnesota-The Role of Coal Tar-based Sealcoat Products as a Source
of PAHs;
Minnesota Pollution Control Agency: St. Paul, MN, 2010,
document tdr-g1-07; http://www.pca.state.mn.us/index.php/view­
document.html?gido: 12960.
(50) Stollenwerk,
J.;
Smith,
J.;
Ballavance, B.; Rantala,
J.;
Thompson,
D.; McDonald, S.; Schnick, E.
Managing dredged materials in the State
of Minnesota;
Minnesota Pollution Control Agency: St. Paul, MN,
2011, document wq-gen2-0l; http://www.pca.state.mn.us/index.php/
view-document.html?gid=12959.
(51) South GA Sealcoating and Striping Sealer perfonnance FAQ;
http://www.sgasealcoating.com/sealcoating_faq.htm#5.
(52) A Better Driveway. Driveway sealcoating
now environ­
mentally friendlYi http://www.abetterdriveway.com/residential_
services.
(53) Hazardous Waste Recycling Exemptions; http://www.epa.gov/
oswIhazard/ recyclingl regulations.htm.
(54) Valle,
S.;
Panero,
M.
Aj
Shor,
L.
Pollution prevention and
management strategies for polycyclic aromatic hydrocarbons in the
New York/New Jersey Harbor;
Harbor Consortium of the New York
Academy of Sciences: New York, NY, 2007.
(55) Van Metre, P.
c.;
Wilson,
J.
T.; Callender, E.; Fuller,
C.
C.
Similar rates of decrease of persistent, hydrophobic contaminants in
riverine systems.
Environ. Sci. Technol.
1998,32 (21), 3312-3317.
3045
dx.doi.org/l0.l021/es203699x I
Environ.
Sci.
Technol.
2012, 46, 3039-3045