Opposition to Proposed Ordinance:

Technical/Scientific Elements

On Behalf of – Pavement Coatings Technology Center

Robert P. DeMott, Ph.D., DABTEnvironmental Toxicologist

rdemott@environcorp.com

Addendum (slides 2-7) G.C. Dubey, STAR, INC.

CITY OF AUSTIN (COA) passed a ban on the use of coal tar sealants, effective Jan. 1, 2006

COA reached the following conclusions:

• High concentrations of Polycyclic aromatic hydrocarbons (PAH’s) are present in sediments within the Austin waterways.

• Primary source being the parking lots sealed with coal tar sealers.

• Ban on coal tar sealers will significantly change water quality and protect organisms in the streams.

PCTC STRONGLY DISPUTES COA’s FINDINGS:

REASONS

1. The COA Study is incomplete. It did not conclusively prove that PAH,s found in the sediments.

2. Current publications on urban sources of PAH’s (including USGS’s publications) do not support COA’s conclusions.

3. Overall PAH’s levels in sediments in Austin are NOT high relative to other cities- USGS stated after the ban.

PCTC STRONGLY DISPUTES COA’s FINDINGS

4. All PAH’s sources and contribution should be quantitatively examined for COA’s claim.

5. 2800 lbs. (1300 kg) of PAH are produced by COA traffic is 130 times greater than PAH’s from water run off from parking lots. – EPA & Texas transportation Institute.

6. Risks are greater for alternative sealer i.e. asphalt based sealer (A/E) will abrade and deteriorate faster.

PCTC STRONGLY DISPUTES COA’s FINDINGS

7. COA did not consider asphalt based sealers as a source of PAH’s.

8. Adverse Economic Impact, using a less durable product (A/E) was not considered by COA.

PCTC’s RESPONSE & ACTION PLAN

1. GET ALL THE DATA ON AUSTIN STUDIES (under Texas Open records Act.)

2. Article in Feb/March issue of Pavement magazine- PCTC’s position, and critique on Austin’s FUZZY science.

3. PCTC’s own PAH studies on Sediment sampling & Source characterization, and national publication & presentation.

PCTC’s RESPONSE & ACTION PLAN

4. Toxicological research- Bio-availability of coal tar sealer particles and the specific effects on sediment dwelling amphibians and invertebrates.

5. Challenge USGS’s findings (“formal request for corrections” procedure.

6. Keep a tab on the PAH noise in Washington- a consultant will monitor.

7. Tell our side of the story- Hire a Public Relations (PR) firm.

Overview

Scientific evaluation incomplete

Current publications contradict anticipated benefit of ordinance

Specific comparison sources and PCTC sediment study should be considered

Substitution risk should be specified quantitatively

CITY OF AUSTIN (COA) passed a ban on the use of coal tar sealants, effective Jan. 1, 2006

Based on studies by:

• COA’s Watershed protection & Development Review dept. (WPDRD)

• United Sates geological Survey (USGS)

Background -- PAHs Are Everyday Urban Constituents

From all combustion processes

- Vehicle exhaust and power generation unchallenged

predominant urban sources overall

Present in construction materials

- Asphalt pavement; roofing; pavement sealers

Used in consumer products

- Shampoos; dyes; medicines; plastics; mothballs

All chemicals are toxic –managing exposure differentiates “pollution” from dandruff control

“The presence and distribution of PAHs in the environment are largely a product of the incomplete combustion of petroleum, oil, coal, and wood. Anthropogenic sources such as vehicles, heating and power plants, industrial processes, and refuse and open burning are considered to be the principal sources to the environment.”

Van Metre, Mahler and Furlong, 2000. Urban Sprawl Leaves its PAH Signature. ES&T 34: 4064.

Vehicles in Austin Emit More Than A Ton of PAHs/Year

USEPA -- PAHs in vehicle exhaust 3.7 x 10-7 pounds/mile

Texas Transportation Institute -- 20.8 million miles traveled per day in Austin

Exhaust contributes 2800 pounds (1300 kg) per year of PAHs

U.S. EPA. 1998. Locating and Estimating Air Emissions from Sources of Polycyclic Organic Matter

Texas Transportation Report. 2005. The 2005 Urban Mobility Report.

Shampoos and Topical Gels

Denorex Shampoo

- 12.5% coal tar solution for

dandruff control

- Each bottle contains 5400

mg of PAH

- Product contains “percent

levels” of PAHs, yet environ-

mental loading managed, not

perceived to pollute

Austin Waterbody PAH Levels Not Extraordinary

Sediment measurements typical – sources: Van Metre et al., 2000. ES&T 34:4064; Geismer report. COA unpubl. results.

0

50

100

150

200

250

Co

nc

. (m

g/k

g)

State of Science

USGS/City team published report documenting coal tar constituents can be washed off coal tar-based pavement sealer

City presented unpublished results on:

- aquarium testing of midges, scuds

- General stream quality around parking lots

No specific analysis of proportionate input from various PAH sources

USGS/City 2005 Study

Mahler, Van Metre, et al. 2005.Parking lot sealcoat: An unrecognized source of urban polycyclic aromatic hydrocarbons. ES&T 39:5560

Determined PAH amount washed from coal tar pavement sealer

Identified PAHs in runoff from in-use parking lots

Could NOT detect different PAH input from coal tar sealer vs. asphalt sealer in-use lots

Recent Study Results

Average PAH yield -- first 3 washings of freshly sealed pavement is 0.046 mg/m2

Mahler, Van Metre, et al., 2005 -- Table S-2

For residential driveway (540 sf) = 2.3 mg

After three simulated rainfall events, average yield drops 10-fold to 0.004 mg/m2

Mahler, Van Metre, et al., 2005 -- Table S-2

City-wide, amounts to 9.8 kg of PAH per year85 rain events, 2% of area as freshly sealed lots

PAH Content from Various Sources (mg)

2187000

111000

2000

2.3 2.3

0.12

5400

0.1

1

10

100

1000

10000

100000

1000000

10000000

Road asphaltbinder (per mile

of road)

Quart usedmotor oil

12 oz. bottle ofDenorex

Vehicle exhaust(12,000

miles/year)

Coal tar sealeddriveway -- 1st

rain event

Rooftoprunoff/rain event

Mesquite-cooked burger

Source Type

PA

H C

on

ten

t (m

g)

Sources of PAH Contributions Equivalent to Rain Event on

Freshly Sealed Residential Driveway (50m 2)

2.7 2.3 2.5 2.3 2.3

0.1

1

10

100

1000

10000

100000

1000000

10000000

1 eyedropper dropused motor oil

3 eyedropper dropsDenorex shampoo

Exhaust from 15 milesof road travelled

Coal tar-sealeddriveway

Rooftop (~1800 sfhome)

PA

H C

on

trib

uti

on

(m

g)

Source: Mahler, Van Metre et al. 2005

Source: Van Metre &Mahler 2003

Eyedropper

Drop

Used

Motor Oil

Auto Exhaust

15 mi.

3 Drops

Denorex

Sealer

Washoff

Driveway

1800 sf

Home

Rooftop

Runoff

Sources of PAH Contributions Equivalent to Rain Event on Freshly Sealed Commercial Lot (1 Acre)

267 225 190 190 171

0.1

1

10

100

1000

10000

100000

1000000

10000000

1 teaspoon used motoroil

1/2 oz. Denorexshampoo

5 seconds of vehicleexhaust in Austin traffic

One-acre coal tar-sealedparking lot

2 large retail buildings(200,000 sf)

PA

H c

on

trib

uti

on

(m

g)

Source: Mahler, Van Metre et al.

2005

Source: Van Metre &Mahler 2003

1 tsp

Used

Motor Oil

½ oz.

Denorex

5 sec. -

Austin

Vehicle exhaust

Sealer

Washoff

1 acre

lot

2 large

Retail

Rooftops

Runoff

Limits of 2005 USGS Study

No comparison to:

- previously measured PAH loading settling from air

- rooftop runoff to drainage features

No specified proportions of overall PAH loading to waterways

Not challenging value/validity of study, these elements simply not included

Beyond Study Findings

Following cited to substantiate pavement sealer releasing “majority” of PAHs to environment

“The average yield of PAHs from sealed parking lots is 50 times greater than that from unsealed lots. PAH assemblages and estimated loads further suggest that sealed parking lots could be dominating PAH loading in watersheds with commercial and residential land use.”

Mahler, Van Metre, et al., 2005. Parking Lot Sealcoat: An UnrecognizedSource of Urban PAHs. ES&T 39:5560

No mention of non-parking lot input

No data to support suggestion –“This issue needs a lot more research.” P. Van Metre, 16 November 2005, Society for Environ. Tox and Chem

Unpublished Aquarium Tests

Selected doses well above known lethal levels – outcome pre-determined by design

Not yet meet scientific standards requiring description of materials used

- Source of test material not disclosed

- Verbal description of sealer “turning to powder” inconsistent with normal properties

- Lack of full chemical characterization precludes repeat by others

Unpublished Stream Surveys

Parking lot/roadway drainage contains many chemicals besides PAHs- Example: Copper from brake linings highly toxic

to stream life – subject of other research groups

Reductions in stream quality routinewith urban drainage

Drought/scour cycles wash outmany Austin creek stretches

Urban Stream Impacts Already Established

USGS documented non-sealer PAH and metal runoff sufficient to impact stream quality

“Concentrations of zinc, lead, pyrene, and chrysene on a

mass per mass basis in a majority of rooftop samples

exceeded the established sediment quality guidelines

for probable toxicity of bed sediments to benthic

biota…. Metal roofing was a source of cadmium and

zinc and asphalt shingles a source of lead.”

p.1741; Van Metre and Mahler 2003. Chemosphere 52:

1727.

Benefit Projection Contradicted by Other Research

“Based on the USGS (United States Geological Survey) study it's pretty apparent that these sealants, particularly the coal tar sealants, are dumping a large portion, probably the majority of the PAHs that we see in the Austin area” – News 8 report, 9 Nov 2005

2005 USGS study does not mention fallout from air and other PAH sources

Previous publications by same USGS research team, however, measured other contributions larger than projection from coal tar sealer

Airborne Transport Measured

Van Metre & Mahler, 2003. The Contribution of Particles Washed from Rooftops to Contaminant Loading to Urban

Streams. Chemosphere 52: 1727-1741.

- Roofs receive 9.2 g/m2 PAH from air

- Percentage of watershed covered by roofs measured from

aerial photos

City-wide – 261 kg of PAHs wash off roofs per year

26X more than washoff from freshly sealed pavement

Airborne Contribution to Lots

Applying USGS airborne settling rate (9.2 g/m2)

- Austin parking lot area = 39 kg/yr PAH from air

4X more than washoff of freshly sealed lots

- Austin street/sidewalk area = 41 kg/yr PAH from air

4X more than washoff of freshly sealed lots

Tire Wear49%

Coal Tar Sealer

Washoff1%

Airborne Fallout to

Streets6%

Airborne Fallout to

Parking Lots6%

Rooftop Runoff

38%

Sealer Washoff Contributes Less Than 1% of PAH Loading

Preliminary, “on paper” analysis indicates need for direct measurement and follow-up.

Major Sources Not Included:

•Used Motor Oil

•Gas station runoff

•Pavement Debris

•Paved banks/ drainage channels

Traffic, Not Urbanization Drives PAH Levels

USGS study of Town Lake concluded:

- “increases in PAHs are proportional to increases in

vehicle traffic”

- “The large increases in traffic offer an explanation

for why PAHs more than doubled in Town Lake

from 1975 to 1990 while percent urban land use

only increased by 5%.”

Source: Van Metre, P.C. et al., 2000. Urban Sprawl Leaves Its Signature. ES&T

34:4064.

Total PAH Increases in Town Lake Coincide with Increase in Vehicle Miles Traveled

Source: Van Metre, Mahler and Furlong. 2000. ES&T 34: 4064 – 4070.

Substitution Risk Requires Analysis

“No Free Lunch…”

More asphalt sealer –

- wears faster

- USGS study did NOT detect a difference in PAH loading from

in use asphalt-sealed lots vs. coal tar-sealed lots

No Sealer

- more pavement debris

- penetration of petroleum-soluble contaminants

Urban Complexities – Environmental Reality

Oil, Vehicle debris – Congress Ave. Drainage

Bridge Drainage Staining

High Expectations for Emerging Science…

“… probably the majority of the PAHs that we see in the Austin

area”

– News 8 report, 9 Nov 2005