Presentation Template

Report
Creative
Dedicated
Experts
PCBs in Building Materials
State of the Science and Regulations / Practical Remediation
(Real World Considerations)
Presented at Vermont Department of Environmental Conservation
November 2012
Agenda
 Overview of the Issue (15 min)
 Why are we here?
Chemistry (20 min)
 Without chemicals, life itself would be impossible
Overview of human health risk (15 min)
 Why do we care?
Overview of the regulations (20 min)
 What are the rules?
 Practical assessment & remediation (35 min)
 What can we do about it?
2
PCBs: Real World Considerations
Overview of the Issue
(Why are we here?)
3
Mug Shot
4
What has brought us all here today?
The resurrection!
Victims of our own success
 Durable, long lasting, high performance,
and extremely useful compound that
continues to haunt us
PCBs have a myriad of uses

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Electrical devices
Paints, adhesives
Plasticizers
Carbonless copy paper (think about
your document archives!)
The stuff of epic Superfund sites and the
headache of electrical utilities and old mills
Regulations came and major sources were
thought to be under control, but….not exactly
5
Certain Technical Paradoxes Have Been “Solved”
 PCBs detected in ancient sediments in U.K. laboratory (Alcock et al, 1994)
 Lighting capacitors, paints, and “…desorption from the fabric of the building”
 Presumably immobile compound found in polar bears
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Global transport like grasshoppers
Volatilize from soil in warm weather
Deposition as temperatures cool
Long distance atmospheric transport
Urban – Rural Gradient
 Indoor air is the source of outdoor air
 Indoor air is a major atmospheric
source of PCBs*
 Soil volatilization not prime source
 Urban “Halo Effect” **
 Steep urban/rural gradients
Higher Concentration
* Jamshidi et al. Concentrations and Chiral Signatures of Polychlorinated Biphenyls in Outdoor and Indoor Air and Soil in a Major U.K. Conurbation
Vol. 41, No. 7 2007/Environmental Science and Technology.
** Diamond & Hodge. Urban Contaminant Dynamics: From Source to Effect. Vol. 41, No. 11, 2007/ Environmental Science & Technology
Lower Concentration
6
PCBs are like a Sci-Fi Super Villain with Global Reach
GAPS - Global Atmospheric
Passive Sampling Study*
 Coordinated air sampling
 40 stations / seven continents
 13 Persistent Organic Pollutants (POPS)
 Kalahari Desert – One of the few remote
sites where PCBs were not detected in air
 The highest PCB air concentrations were
detected in urban centers
* Pozo, et al., Toward a Global Network for Persistent Organic Pollutants in Air: Results from the GAPS Study, Vol. 40, No. 16, 2006 / Environmental Science & Technology.
7
So if Urban Areas are the Hot Spots*….
…then the problem scope is huge!
 Building stock – Over half of the concrete/masonry buildings in the U.S.
were built between 1955 and 1975…peak PCB use timeframe
 Herrick (2010) – “…one-third of the schools constructed from
1950 to 1970 will be found to contain PCBs…”
 Can we have a quick show of hands?
* Diamond & Hodge. Urban Contaminant Dynamics: From Source to Effect. Vol. 41, No. 11, 2007/ Environmental Science & Technology
8
Importance of Building Age Category
1348 samples
10,000 ppm PCB
1,000 –10,000 ppm PCB
ND – 1,000 ppm PCB
*Source: Kohler et al, 2005 Environmental Science and Technology, 2005, 39, 1967-1973
9
Back to the opening question: Why are we here today?
 1992 – Realization: Building envelope PCBs impact indoor air
 Europe – Benthe et al, 1992, Johansson et al, 2001
 U.S.A. – Leung 1996 - School indoor air/caulking association
 1990s to 2000s – Awareness grows: PCB/Indoor air research blossomed
 Lots of Ph.D. theses were born
 Effects on indoor air became well documented (Vorhees 2001)
 All before Herrick pronouncement of unrecognized sources in 2004
 First project in Region 1 in late 1990s
 2000s – Big U.S. projects hit the news
 Major PCB building materials remediation projects in EPA Region 1
 European abatement well ahead of the U.S.
 2000 to 2010 – Activism increases
 Grass roots – www.pcbinschools.org (school caulk sample 2004, website 2007)
 Contractor unions – 2003 Harvard School of Public Health collaboration
 Educators – 2010 Massachusetts Teachers Association/research collaboration
 2009 and beyond – EPA issues limited guidance (initially focused on caulking)
 PCBs in Caulk in Older Buildings – September 30, 2009
 Inaugurated a new research effort
 Enormous progress in research and in the publication of various guidance documents
1990
2000
2010
10
Any questions before we move on?
11
Without Chemicals, Life Itself Would Be Impossible
A Quick PCB Chemistry Lesson
12
It pays to advertise….or is it an “un-wanted poster?”
13
The Basics
 Polychlorinated biphenyls
 Poly prefix meaning “many”
 Chlorine is an element
 Biphenyl is the parent molecule
 Translation - PCBs = biphenyl with many chlorines
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PCBs Marketed as Technical Mixtures
(Aroclor is essentially a brand name)
 Monsanto was only U.S.
producer
 1.4 billion pounds produced
 >50 of 209 different congeners
were used in the various
Aroclor mixtures
 Last 2 digits = amount of
chlorine on a weight basis
 Aroclor 1254 = 54% Chlorine
by Mass
Technical Mixture –
Think of it like 10W-40 Motor Oil. A
chemical mixture composed to meet
defined performance criteria.
15
Let’s Add Some Definition
 PCB Mixtures and Trade Names - With few exceptions, PCBs were
manufactured as a mixture of various PCB congeners, through
progressive chlorination of batches of biphenyl until a certain target
percentage of chlorine by weight was achieved.
 Aroclor - A PCB mixture produced from approximately 1930 to 1979.
It is one of the most commonly known trade names for PCB mixtures.
There are many types of Aroclors and each has a distinguishing suffix
number that indicates the degree of chlorination.
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Let’s Add Some Definition (continued)
 Congeners - PCBs are a class of chemical compounds in which 1–10
chlorine atoms are attached to the biphenyl molecule. A large
number of chlorinated compounds are possible (209). The 209
possible compounds are called congeners.
 Homologs - PCBs can also be categorized by degree of chlorination.
The term “homolog” is used to refer to a group of PCB congeners
with the same number of chlorines (e.g., trichlorobiphenyls).
Congeners with different substitution patterns within a homolog
group are referred to as isomers. For example, the dichlorophenyl
homolog contains 12 isomers. All the PCB chemicals that have the
same number of chlorine atoms are said to belong to the same
homolog group.
17
PCBs Are Complex Chemical Mixtures
(Actual Lab Gas Chromatogram)
Number Refers to Number of Chlorines in PCB
Source: GC Chromatogram provided by Contest Labs, MA
18
Composition of PCB Aroclor Mixtures
(% Chlorine by Homolog Number)
60
Aroclor
1221
50
1242
1248
40
1254
1260
% CHLORINE /HOMOLOG
30
20
10
0
# Chlorines 1
# Congeners 3
2
12
3
24
4
42
5
46
6
42
7
24
8
12
9
3
10
1
Total = 209
For Aroclor by Aroclor congener plots, visit this EPA website:
http://www.epa.gov/osw/hazard/tsd/pcbs/pubs/aroclorplots.pdf
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Laboratory Analyses (Extraction and Analysis)
 Extraction
Waters 3510C (separatory funnel)
Solid 3540C (soxhlet)
 Analysis
EPA SW-846 Method 8082A, (PCB Aroclors), 2007
EPA Method 680 (PCB Homologs), 1985
EPA Method 1668B (PCB Congeners), 2008
Until the regs change, or unless you apply for a project-specific change under
Subpart Q of TSCA, Soxhlet Extraction is a must for solid samples in Region I.
Why should EPA change?
1. It’s slow….18 hour extraction
2. It’s not green….it’s labor intensive and uses a lot of solvent (methylene chloride)
3. Other methods (pressurized fluid extraction [3545A], microwave extraction [3546]) are
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faster and just as efficient, rigorous, and robust
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Pros and Cons of the Analytical Methods
Method
Pro
Con
Aroclors
(8082A)

Relatively inexpensive (<$100 per
sample)
Widely available analytical service
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Affected by weathering
Although still used, it is not the best
for air sampling
Homologs
(680)
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Provides a good estimate of total PCBs
Overcomes weathering of Aroclors
Good option for air analysis (Aroclors
may not evaporate as tech. mixtures)
More accurate (not dependent on
human interpretation)
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Expensive (~$300 per sample)
A service not offered by all
laboratories
Provides a breakout of all the individual
PCB chemicals present
Provides quantitation of the dioxin-like
congeners
Provides added flexibility in a risk
assessment. More accurate (not
dependent on human interpretation)
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Expensive (~$800 per sample)
Few laboratories offer the analysis
(less than with homologs)
Not all of the laboratories do it well
(engage your QC chemist)
Cheap
May help with faster delineation
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Congeners
(1668B)
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Screening kits
(various)
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Subject to interferences
Generally higher detection limits
No standing under the Compendium
of Analytical Methods (CAM) in
Massachusetts (not applicable to VT).
Not an option for risk assessment
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Any questions before we move on?
22

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