Opposition to Proposed Ordinance: Technical/Scientific Elements

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Opposition to Proposed Ordinance
Technical/Scientific Elements

• On Behalf of Pavement Coatings Technology
  Center
• Robert P. DeMott, Ph.D., DABT
• Environmental Toxicologist
• rdemott_at_environcorp.com
• Addendum (slides 2-7)
• G.C. Dubey, STAR, INC.

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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 (PAHs) 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.

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PCTC STRONGLY DISPUTES COAs FINDINGSREASONS

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 PAHs
   (including USGSs publications) do not support
   COAs conclusions.
3. Overall PAHs levels in sediments in Austin are
   NOT high relative to other cities- USGS stated
   after the ban.

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PCTC STRONGLY DISPUTES COAs FINDINGS

• 4. All PAHs sources and contribution should be
  quantitatively examined for COAs claim.
• 2800 lbs. (1300 kg) of PAH are produced by COA
  traffic is 130 times greater than PAHs from
  water run off from parking lots. EPA Texas
  transportation Institute.
• Risks are greater for alternative sealer i.e.
  asphalt based sealer (A/E) will abrade and
  deteriorate faster.

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PCTC STRONGLY DISPUTES COAs FINDINGS

• 7. COA did not consider asphalt based sealers as
  a source of PAHs.
• 8. Adverse Economic Impact, using a less
  durable product (A/E) was not considered by COA.

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PCTCs 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- PCTCs position, and critique on
  Austins FUZZY science.
• 3. PCTCs own PAH studies on Sediment sampling
  Source characterization, and national publication
  presentation.

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PCTCs 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 USGSs 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.

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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

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

• Based on studies by
• COAs Watershed protection Development Review
  dept. (WPDRD)
• United Sates geological Survey (USGS)

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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

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• 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. EST 34 4064.

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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.
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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

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Austin Waterbody PAH Levels Not Extraordinary

• Sediment measurements typical sources Van
  Metre et al., 2000. EST 344064 Geismer
  report. COA unpubl. results.

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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

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USGS/City 2005 Study

• Mahler, Van Metre, et al. 2005.Parking lot
  sealcoat An unrecognized source of urban
  polycyclic aromatic hydrocarbons. EST 395560
• 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

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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
  year 85 rain events, 2 of area as freshly
  sealed lots

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Source Mahler, Van Metre et al. 2005
Source Van Metre Mahler 2003
Eyedropper Drop Used Motor Oil
1800 sf Home Rooftop Runoff
Sealer Washoff Driveway
Auto Exhaust 15 mi.
3 Drops Denorex
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Sealer Washoff 1 acre lot
2 large Retail Rooftops Runoff
5 sec. - Austin Vehicle exhaust
1 tsp Used Motor Oil
½ oz. Denorex
Source Mahler, Van Metre et al. 2005
Source Van Metre Mahler 2003
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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

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Differing Sample Types
Source Courtesy of City of Austin, WPDRD
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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 Unrecognized Source of Urban
  PAHs. EST 395560
• 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

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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

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Unpublished Stream Surveys

• Parking lot/roadway drainage contains many
  chemicals besides PAHs
• Example Copper from brake linings highly
  toxicto stream life subject of other research
  groups
• Reductions in stream quality routinewith urban
  drainage
• Drought/scour cycles wash outmany Austin creek
  stretches

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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.

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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

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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

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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

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Sealer Washoff Contributes Less Than 1 of PAH
Loading

• Major Sources Not Included
• Used Motor Oil
• Gas station runoff
• Pavement Debris
• Paved banks/ drainage channels

Preliminary, on paper analysis indicates need
for direct measurement and follow-up.
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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. EST 344064.

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Total PAH Increases in Town Lake Coincide with
Increase in Vehicle Miles Traveled
Source Van Metre, Mahler and Furlong. 2000.
EST 34 4064 4070.
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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

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Urban Complexities Environmental Reality
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• Oil, Vehicle debris Congress Ave. Drainage

Bridge Drainage Staining
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High Expectations for Emerging Science

• probably the majority of the PAHs that we see
  in the Austin area
• News 8 report, 9 Nov 2005