453N90009
NATICH
NEWSLETTER
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
State and Territorial Air Pollution Program Administrators
Association of Local Air Pollution Control Officials
Produced by the National Air Toxics Information Clearinghouse January 1990
Florida Considers Air Toxics During Soil Cleanup
As they comply with new
Federal regulations designed to
protect ground water from contam-
ination,* States removing contami-
nated soils consider air toxics ques-
tions concurrently with soil and
water issues. In the State of
Florida, the Division of Waste
Management handles an air review
of sites with contaminated soil as
part of the hazardous waste permit
process. Although Florida has no
regulation in place, the State has
developed guidelines for determin-
ing acceptable ambient limits for
air toxics from such sites. At pre-
sent, decisions on the air toxics
aspects of soil cleanup are made
on a case-by-case basis.
Depending on whether the
State has classified the soil at a
site as hazardous waste (in which
case it is subject to RCRA re-
quirements) or contaminated
*See "EPA Issues Policy Directive
on Air Strippers at Superfund
Sites," in the December 1989 issue
of the Newsletter.
(continued on page 10)
OAQPS Publishes
Butadiene Emission Report
OAQPS has published a report
that provides information on
estimating emissions of 1,3-
butadiene from selected sources.
This report is entitled "Locating
and Estimating Air Emissions
from Sources of 1,3-Butadiene"
(EPA-450/2-89-021). This emission
document is a part of the report
series of "Locating and Estimating
Air Emissions from Sources of
(Substances)." The purpose of the
1,3-butadiene report is to assist air
pollution control agencies and
others who are interested in
locating potential air emitters of
butadiene and making preliminary
estimates of the emissions re-
sulting from these sources. This
document contains available infor-
mation on the types of sources that
may emit butadiene and emissions
data. Included are emission factor
estimates that indicate the poten-
tial for butadiene to be released
FEB 71990
from operations within the sources
described in the document. Over-
views of procedures for source
sampling and analysis of air toxic
emissions from these sources are
also provided.
Single copies of this report are
available by writing the EPA
library at MD-35, Research
Triangle Park, NC 27711, or by
calling (919) 541-2777 or (FTS)
629-2777. The process to make the
reports available through the Na-
tional Technical Information Ser-
vice (NTIS) for a fee has been in-
itiated. No NTIS order number
has yet been assigned to the
report. For further information on
the report, contact Anne Pope,
EPA, OAQPS, Noncriteria Pollu-
tant Programs Branch (NPPB),
MD-15, Research Triangle Park,
NC 27711, (919) 541-5373, (£TS)
629-5373.	T . . r
ry V •
u. ; 		
In This Issue
Florida Considers Air Toxics
During Soil Cleanup 1
OAQPS Publishes Butadiene
Emission Report 1
First Denver Brown Cloud
Study Results Released 2
EPA to Use Reg Neg to
Control Equipment Leaks 2
Region X Exchanges Ideas
at Coordinators' Retreats 3
Massachusetts Sets AALs
for Air Tbxics 4
EPA Collates Survey of State
Use of TRI Data Base 4
California, Region IX
Develop Noncancer Risk
Assessment 5
EPA Will Regulate
Sewage Sludge Disposal 7
EPA lb Begin Study of
Consumer Products., 8
X f OAQPS Conducts
Noncancer Ris1"1
pgQTFflTIflB
,ii i ACT
08,311

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First Denver Brown Cloud Study Results Released
The Governor of Colorado and
the Mayor of Denver, as well as
other elected officials and civic
leaders, have realized for some
time that poor air quality in the
Denver metropolitan area presents
a health hazard and a detriment to
economic development. The most
visible aspect of the problem,
known as the Denver Brown Cloud,
is an episodic phenomenon in
which a white to brown haze
envelopes the metro area. This
haze occurs most often during the
winter and sometimes persists for
several days. The Metro Denver
Brown Cloud Study was initiated
in 1987 to assess this problem.
The Colorado Department of
Health and Region VIII of the U.S.
Environmental Protection Agency
provided technical assistance.
The goal of the 1987-1988
study was to determine the relative
contribution of sources of the win-
ter brown cloud, thus providing
both scientific data and socio-
economic information for policy
makers. The technical portion of
the study was designed to com-
plete the monitoring and analysis
necessary to determine the major
pollution emission sources, and to
compare the contributions of
power plants when they use coal or
natural gas in generating power.
The socioeconomic portion of the
study focused on 10 potential con-
trol strategies, at least one of
which was related to each of the
primary sources examined in the
technical study.
The study was unique in
several aspects. First, the funding
and implementation of the project
was made possible almost entirely
by the private sector. About $1.5
million was provided by business.
Second, the Public Service Com-
pany was willing to burn natural
gas instead of coal for a 45-day
period during the study. The pur-
pose of fuel switching was to deter-
mine if there was a noticeable
reduction in particulate concentra-
tions during the period when gas
was burned. Denver was an ideal
location to conduct this type of ex-
periment due to its remote location
from other large industrial sources
and urban centers.
(continued on page 11)
EPA To Use Reg Neg To Control Equipment Leaks
Fugitive emissions of toxic
chemicals and volatile organic
compounds (VOCs) from equip-
ment leaks - such as valves,
pumps, and flanges - are a signifi-
cant source of air pollution. In-
deed, by some estimates, leaks
constitute between one- and two-
thirds of all routine, nonaccidental
emissions from chemical plants.
Moreover, because they are re-
leased near the ground, their im-
pact is 10 - 40 times greater than
equal releases from stacks.
Current Federal regulations re-
quire that equipment be inspected
quarterly for leaks with a portable
hydrocarbon detector. If concentra-
tions exceed 10,000 ppm, the
source is identified as a "leaker,"
and maintenance is required. This
approach is known as "leak detec-
tion and repair" (LDAR).
The current LDAR program
can reduce uncontrolled emissions
by about 60-70 percent. The ac-
tual frequency rate and the asso-
ciated emissions vary widely,
however, as a function of the
original design of the process unit,
such as the number of valves,
pumps, and flanges; the age of the
process unit; design and construc-
tion of each component; quality of
maintenance; standard operating
procedures used by the company;
training provided to employees;
and commitment to ensure low
emissions. It is not clear just
what combination of factors
guarantees low emissions nor how
to achieve them through enforce-
able regulations.
In addition, current regulatory
approaches do not provide the
means for calculating the level of
emissions. Yet the accurate quan-
tification of fugitive emissions
from equipment leaks is becoming
a high priority. Specific emission
levels are necessary for baseline
and residual risk assessments for
new regulations, for issuing per-
mits for new facilities, and for
establishing appropriate emission
fees. Further, companies must
report emissions under SARA
Title III (the Community Right-to-
Know Act). These figures were
widely publicized early this sum-
mer and focused considerable
public attention on the level of
emissions of toxics and VOCs.
Not only does the current
regulatory approach not achieve
accurate estimates of the actual
emissions, it does not provide in-
centives or credit to firms for
establishing programs and
facilities to achieve the best con-
trol. The approach does not ensure
emission rates that are readily
achievable.
The EPA recently convened a
regulatory negotiation (reg neg) to
address these shortcomings.
Representatives of EPA; the
chemical, petroleum, rubber, and
pharmaceutical industries; environ-
mental organizations; and State
and local governments are working
together on a committee to develop
a consensus on a proposed rule
that would:
- Revise the emission factors for
fugitive emissions of VOCs
2

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Reg Neg (continued)
from equipment leaks, leading
to a better quantification of the
magnitude of the leaks;
Develop a new standard based
upon best technology and lowest
achievable rates for control of
toxic fugitive organic emissions
from equipment leaks for the
source categories that will be
the subject of the EPA's for-
thcoming HON (Hazardous
Organic National Emission
Standards for Hazardous Air
Pollutants); and
Develop a format that could be
used to implement a risk-based
standard for toxic organic emis-
sions from equipment leaks.
Specific risk limits or goals will
not be a subject of the negotia-
tions, however.
Thus far, the committee has
reviewed conceptual approaches
that would provide incentives for
good performance and disincentives
for poor performance to encourage
the construction and operation of
high quality, low leak plants. The
discussions have involved monitor-
ing strategies, maximum allowable
leak frequencies, the definition of a
leak, the regulatory consequences
of various findings during a
monitoring or following a series of
monitorings, ways to phase in a new
rule, and a number of factors that
could be taken into account when
developing a standard. The com-
mittee has also begun consideration
of approaches for assessing emis-
sions. The committee is scheduled
to meet again at the end of Feb-
ruary. For further information, call
Rick Colyer, EPA/SDB, at (919)
541-5262 or (FTS) 629-5262.
Region X Exchanges Ideas at Coordinators' Retreats
Good communication among
the Federal, State, and local agen-
cies has always been an important
objective but one that is often dif-
ficult to achieve and maintain. One
way that Region X pursues this
goal is through periodic retreats
for the air toxics coordinators from
its four State agencies - Alaska,
Idaho, Oregon, and Washington -
and its largest local agency - the
Puget Sound Air Pollution Control
Agency (PSAPCA).
How the Retreats Work
The Region X retreat idea was
developed by Elizabeth Waddell,
the Air Toxics Program Manager
for the Region, who schedules
each retreat and plans the agenda
and meeting place. Since funds for
travel and hotel accommodations
are limited or unavailable, meeting
time has to be extracted from an
"official" meeting or conference
such as a regional meeting of the
Air and Waste Management
Association (AWMA). The retreats
are small (about seven people,
maximum) and short (4 hours max-
imum time). The air toxics coor-
dinators receive a draft agenda for
the retreat ahead of time, along
with a request for comments.
The retreat itself consists of
briefings, presentations, and ques-
tion/answer sessions. One person
takes notes. The main goal of
these retreats is information ex-
change, according to Waddell: "We
have found that nothing can
substitute for the face-to-face in-
teraction achieved at these
meetings. While they might not
work for every region, they have
been very effective for us. Our
only concerns are that we are
unable to meet often enough, and
we always have much more
material to discuss than we have
time."
Recent Retreat Summarized
The latest and most successful
retreat was held in November 1989
at the annual meeting of the
Pacific Northwest International
Section of AWMA. This was the
first time the Region was able to
have representatives from all four
States and PSAPCA.
The retreat began with a brief-
ing on the information obtained at
the most recent national EPA Air
Toxics Coordinators' meeting held
in Research THangle Park, North
Carolina. With Clean Air Act
amendments a real possibility,
everyone was interested in discuss-
ing the proposed amendments and
their ramifications. Alaska
spearheaded an effort to develop
northwest State concurrence on
key aspects of the amendments
and followed through after the
meeting with a strategy to lobby
Congress. Although the regional
office cannot participate in this
lobbying effort, it was pleased to
see the States working together
toward a common goal.
Participants were also keenly
interested in the status of each
agency's air toxics program and
particularly the progress that
Washington has made in develop-
ing an air toxics regulation. It is
through these discussions that
focus on the similarities and dif-
ferences in regulatory frameworks,
academic backgrounds, program
philosophies, source problems,
even resources, that retreat par-
ticipants learn what has been tried
and what is possible. Certainly not
all of what is learned can be ap-
plied when participants return to
their offices, but the information
exchange does foster thinking
about problems in different ways,
and that may lead to new solutions.
For further information on the
regional retreat, call Elizabeth
Waddell, EPA Region X, at (206)
442-8578, (FTS) 399-8578.
3

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Massachusetts Sets AALs For Air Toxics
The Massachusetts Depart-
ment of Environmental Protection
(DEP) has finalized a methodology
for deriving Allowable Ambient
Limits (AALs) for air toxics. Sum-
marized in "Chemical Health Ef-
fects Assessment Methodology
and the Method to Derive Allow-
able Ambient Limits (CHEM/
AAL)," the methodology was
originally developed for use in per-
mitting new sources. Its use is cur-
rently being phased in for selected
sources.
The current CHEM/AAL
document is the product of a joint
effort involving the Office of
Research and Standards and the
Division of Air Quality Control
that began more than 5 years ago.
A draft version of this document
underwent peer review in June
1985. Then, after refinements
prompted by changes in method-
ology, the DEP held two public
meetings in June 1989 to present
the CHEM/AAL document to the
public. The current document in-
cludes revisions based on com-
ments received on the draft, and
an extensive in-house review of the
proposed methodology. Changes
made included assessment of
available pharmacokinetic data,
consideration of nonpositive data*
separate assessment of threshold
and nonthreshold effects, use of a
multimedia exposure adjustment
factor, and use of quantitative
cancer risk assessment for those
chemicals that have adequate
quantitative cancer potency data.
In CHEM, valid epidemiologi-
cal, clinical, and experimental in-
formation from primary and peer-
reviewed secondary sources is used
to systematically identify and
evaluate the potential adverse
health effects of chemicals. The
health endpoints evaluated include
acute/chronic toxicity, carcinogeni-
city, mutagenicity, and develop-
mental/reproductive toxicity. The
method used to derive AALs
establishes ambient air limits for
specific chemicals based on the
health data provided by CHEM.
The health data from CHEM are
incorporated either through a series
of adjustment and uncertainty fac-
tors applied to a chosen most ap-
propriate occupational limit to pro-
vide protection to the general
public against continuous exposure
and to account for gaps and inade-
quacies in the data, or through the
use of quantitative cancer risk
assessment when there are ade-
quate quantitative data on carcino-
genicity.
The AAL-development
methodology incorporates deriva-
tion of both a Threshold Effects
Exposure Limit (TEL), which ad-
dresses threshold effects; and a
Nonthreshold Effects Exposure
Limit (NTEL), which addresses
nonthreshold effects. The lower
of the two limits is set as the AAL.
Thus the selection of the AAL is
based on the most sensitive health
effect. AALs and TELs are purely
health-based numbers conserva-
tively derived to be protective of
public health. Thus far the DEP
has developed about 110 AALs
and TELs, most of which were
chosen not on the basis of hazard
but to test the methodology on
representative kinds of chemicals.
The TELs are to be applied as
24-hour averages and the AALs as
annual averages. They should be
used together for each chemical to
be protective of public health for
both threshold and nonthreshold
effects.
Limited numbers of copies of
the CHEM/AAL document are
currently available through the
DEP's Office of Research and
Standards. Bound copies of this
document will be available by mid
1990 from the Massachusetts State
House Bookstore, State House,
Boston, MA, (617) 727-2834. For
further information on the method-
ology, call Diane Manganaro or
Carol Rowan West at the
Massachusetts Office of Research
and Standards at (617) 556-1158.
"That is, in cases in which a study
was conducted twice, and yielded
both a positive and a negative report,
both sets of data were considered.
EPA Collates Survey of State Use of TRI Data Base
As the requirements of the
Emergency Planning and Com-
munity Right-to-Know Act have
been implemented, the resulting
Toxic Release Inventory (TRI)
data were expected to draw public
attention to chemical releases and
transfers. It was anticipated that
this increased public awareness of
industrial chemicals would lead to
increased public involvement in
the process of regulating chemi-
cals. Because air toxics are usually
regulated at the State level, public
response to the data about chem-
ical emissions was expected to in-
fluence State air toxics regulatory
programs.
To assess the influence of TRI
data on State air toxics programs
and policies, air toxics officials in
nine States were surveyed in 1989.
The survey questionnaire included
sections addressing the following
topics: (1) how have the TRI report-
ing requirements and air emissions
data influenced the Agency work-
load and resources; (2) what type
of TRI-related questions have been
asked, which questions were dif-
ficult to answer, and what resources
are used to help explain TRI; (3)
how have the public, the regulated
community, and the media
responded to the TRI air emis-
sions data; and (4) how will
4

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(continued)
the TRI data be used, and what
additional information would make
the TRI data more useful?
The following nine States par-
ticipated in the survey: Alabama,
California, Kansas, Louisiana, New
York, Ohio, Rhode Island, Virginia,
and Washington. The States were
selected based on their differing
regulatory histories and TRI pro-
files, and on evidence of use of the
TRI data. Each State answered
questions regarding the influence
of TRI reporting requirements and
data on their programs.
Survey Results Summarized
The results of these surveys
were summarized in an EPA study
that suggested that States' air tox-
ics control programs have been in-
fluenced by the TRI-data in three
ways: (1) their workload has been
increased; (2) their visibility has in-
creased because of TRI related
questions; and (3) some of their
programs are being altered to in-
corporate use of TRI data.
Six of the surveyed States used
the TRI data to decide what and
where to monitor. Three States are
using the data to alter their permit
system, by increasing the number
of chemicals and sources permitted
and creating permits for fugitive
emissions. Three of the States use
the data in enforcement or com-
pliance actions involving com-
panies that did not report or com-
panies that reported emissions
higher than permitted levels.
The TRI data have also had an
indirect influence by encouraging
companies to avoid bad publicity
with voluntary emissions reduc-
tions. Companies have initiated
voluntary emissions reductions in
seven of the survey States.
Recommendations Listed
This study concluded that
EPA can help the States make the
most of the TRI data by: (1) en-
abling them to generate and re-
spond to public attention quickly
and easily; and (2) providing
examples of how other States have
used the TRI data to advance their
air toxics control efforts.
To help the States generate
and respond to TRI-related publi-
city, the EPA should provide: (1)
risk communication training; (2)
sample press releases; and (3) sam-
ple answers for frequently asked
questions. The TRI-related publici-
ty is important because it leads to
voluntary emissions reductions.
The EPA should endeavor to
provide models of TRI use that
will help the States develop their
programs, based on programs in
States that have air toxics pro-
grams of similar style and
experience.
Copies of the summary report,
"Influence of the Toxic Release In-
ventory on State Air Toxics Con-
trol Programs," are available from
John Vandenberg (EPA, MD-13,
RTP, NC 27711), telephone (919)
541-5352, (FTS) 629-5352.
California, Region IX Develop Noncancer Risk Assessment
by David C. Lewis, U.S. Environmental Protection Agency, Region IX, and
George V. Alexeeff, California Department of Health Services:
California and Engineering
Science, with some grant assis-
tance from Region IX have
developed a method of carrying
out risk assessments for noncancer
health effects that has certain ad-
vantages over approaches now
used. The new method is described
here through comparison with the
modified No Observable Adverse
Effects divided by uncertainty fac-
tors (NOAEL/UF) approach.
Existing Risk Assessment
Methodology Outlined
Available data for estimating
risks to humans include experi-
mental studies of animals and, to a
lesser extent, human exposure
studies, human case reports, and
epidemiologic studies. Human tox-
icity data have an obvious advan-
tage over animal data; however,
they usually arise from accidental
exposure to ill-defined concentra-
tions and durations, or from ex-
periments of limited sample size
and exposure causing minimal sub-
jective or biochemical effects. Ex-
perimental animal studies often
have a superior study design and
better description and quantitation
of toxicity over a range of doses.
However, these may have greater
uncertainties due to species dif-
ferences. Therefore, uncertainties
remain, regardless of the type of
data used.
In addition to interspecies con-
siderations, studies used in risk
assessments generally require ad-
ditional extrapolations. These may
include extrapolation: (1) from a
threshold for a severely toxic
response to minimally observable
effects (e.g., slight irritation); (2) to
different exposure durations; and
(3) between the experimental sam-
ple response and the general
population.
Risk assessment for noncancer
effects presumed to exhibit bio-
logical thresholds has typically
been based on determining a max-
imum dose level causing NOAEL.
The NOAEL divided by UFs is
used as an estimate of acceptable
dose. An important limitation of
this method is that it lacks account-
ing for differences in study size,
5

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Noncancer (continued)
and may in fact have a tendency to
derive higher limits from smaller
and less definitive studies.
New Approach to Risk
Assessment Described
A practical method has been
developed for acute toxicity to: (1)
allow the use of the best experi-
mental data, (2) replace traditional
order-of-magnitude uncertainty
factors with species-specific and
chemical-specific extrapolation fac-
tors, and (3) consider sources of
uncertainty. The approach
estimates a response threshold
concentration from multiple and
single concentrations or NOAEL
data. Adjustments and uncertainty
factors were then applied to ac-
count for differences between
experimental study and human
exposure to derive an acute ex-
posure limit (1-hour duration). This
method was employed in evaluating
noncancer health effects for 12
pollutants.
The response threshold or
defined practical threshold (DPT)
concentration is defined as the con-
centration expected to cause the
observed response in no more than
1 percent of the exposed subjects.
A 1 percent DPT is below the level
at which an increased incidence of
a general toxic effect that is non-
lethal, noncarcinogenic, and non-
teratogenic is likely to be detected.
DPTs for lethal and reproductive
effects could be set at lower levels.
Furthermore, 1 percent represents
a level of safety approximately
equivalent to that previously used
in calculating human NOAELs
based on small experimental
studies.
The DPT estimates were cal-
culated by methods appropriate for
the type of study being evaluated
using log-probit (log concentration
vs. probit response) analysis.
The extrapolation factors
developed and applied were of
three types: (1) a time adjustment
factor (TAF); (2) a species extra-
polation factor (SEF); and (3) a
response severity factor (RSF).
The TAF accounts for the dif-
ferences in exposure duration for
data upon which the DPT is based.
The SEF estimates the species dif-
ferences in responding to a chemi-
cal insult for the studies used in
the DPT derivation. The RSF is
an adjustment made to estimate a
concentration causing no or only
minimal reversible effects when
the DPT is based on a greater than
minimal response.
New Approach Compared to
Approximated Reference Doses
A comparison of ambient con-
centration limits (ACLs) to values
derived from NOAELs was made
for 12 compounds (see Table 1).
Results with the new approach
suggest several advantages. First,
this approach favors larger and
more complete studies. Second,
the method allows for incorpora-
tion of both dose-response data
and LOAEL or NOAEL data.
Third, a sample size-dependent
result is obtained. Fourth, ex-
trapolation factors are based on
chemical-specific and species-
specific data.
Overall, the new approach may
lessen the uncertainty of the risk
assessment process, primarily by
(1) incorporating most available
data, (2) making adjustments for
sources of uncertainty, and (3)
using data-based extrapolation fac-
tors. Given the level of uncertainty
and health-protective assumptions
involved in many of the steps in
the risk assessment process, the
results may be viewed as screening
values that are expected to be at or
below concentrations capable of
causing adverse effects in the
general population. As better data
become available and methods are
refined, the degree of certainty of
estimates should be improved and
the degree of conservatism re-
quired should be lessened.
The above data and informa-
tion were generated in part
through a grant obtained from
EPA Region IX. The project was
temporarily suspended due to lack
of funds, but is expected to resume
in spring of 1990. Once the project
is reactivated, the first step will be
to finalize the 12 values reported in
Table 1.
For additional information,
contact George Alexeeff, California
Department of Health Services,
2151 Berkeley Way, Room 515,
Berkeley, CA 94704, or call him at
(415) 540-2907.
Table 1.
Comparison of Twelve Acute
Concentration Limits (ACLs)
as Determined By the DPT/SF
and NOAEL/UF Approaches''1*
ACL (ppm)
Chemical	DPT/SF NOAEL/UF
Ammonia
3
1
Arsine
0.04
0.05
Carbon
0.03
0.5
tetrachloride


Chlorine
0.008
0.02
Formaldehyde
0.3
0.07
Hydrogen chloride
2
0.2
Hydrogen cyanide
3
0.1
Hydrogen fluoride
1
1
Hydrogen sulfide
8
0.08
Methylene chloride
1
8
Perchloroethylene
1
3
Phosgene
0.003
0.01
aDefined Practical Threshold (DPT) concen-
tration divided by chemical- and species-
specific factors (SF) and No Observed Adverse
Effect Level (NOAEL) divided by order of
magnitude uncertainty factors (UF).
bThese values should be considered
preliminary. They have not undergone peer
review. However, they reflect the types of
numbers that would be provided using such
an approach.
6

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EPA Will Regulate Sewage Sludge Disposal
Table 1.
Summary of Control Efficiency Data for Metals
Contaminant
Number of
Incinerators
Tested
Regulatory
Minimum Mean Maximum 10th	yaj
(%)	(%)	(%) Percentile (%)
Arsenic
7
93.90
98.62
100.00
95.52
96
Cadmium
24
40.25
88.54
99.98
65.15
65
Chromium
23
88.92
99.16
100.00
96.12
96
Lead
24
34.22
92.24
99.67
66.73
67
Nickel
19
89.15
98.68
100.00
95.00
95
The EPA is currently examin-
ing public comments received on a
new regulation to govern the final
use and disposal of sewage sludge.
Although the authority for the pro-
posed regulation is Section 405 of
the Clean Water Act, the proposal
does have ramifications for air tox-
ics since incineration is one of the
five methods of use and disposal
the regulation will cover* During
sludge incineration, pollutants
such as arsenic, cadmium, chro-
mium, lead, and various organics**
may be emitted. Following is a
short overview of the incineration
portions of the proposed Standards
for the Disposal of Sewage Sludge
(54 FR 5746, proposed February 6,
1989, public comment period end-
ing in August).
How Many Incinerators
Are There?
Currently, 169 publicly owned
treatment works (POTWs) use 282
incinerators, most of which were
built before 1973. The most com-
mon type of incinerator is multiple
hearth, followed by fluidized bed
as next most common, and a small
number of electric incinerators.
The proposed rule is expected to
cover approximately 5,300 of some
15,300 POTWs.
Who Must Comply?
Both publicly and privately
owned treatment works that
generate or treat domestic sewage,
as well as those who use or dis-
pose of the sludge, must comply.
The proposed regulation does not
apply to incinerators firing sludge
containing 50 ppm or more of
PCBs or to sludge fired with solid
waste.
Regulatory Requirements
Outlined
Many States already regulate
emissions of sewage sludge in-
cinerators, although no State has
established a limit for lead emis-
sions from incineration. Further,
the National Ambient Air Quality
Standards (NAAQS) for lead and
the National Emission Standards
for Hazardous Air Pollutants
(NESHAP) for beryllium and mer-
cury were used in developing the
pollutant limits for these pollutants
when sludge is incinerated. Finally,
the New Source Performance Stan-
dards for Sewage Sludge Inciner-
ators also exists. Owners or opera-
tors of sewage sludge incinerators
also must ensure that their opera-
tions comply with these existing
regulations.
How Was the Exposure
Assessment Carried Out?
-	Inhalation was chosen as the
single exposure pathway in ana-
lyzing the exposure to the Max-
imum Exposed Individual (MEI).
-	Atmospheric dispersion model-
ing was used to relate emission
rates to ground level exposure
concentrations.
The EPA's Integrated Air
Cancer Project (IACP) has recently
completed an intensive 4-month
field monitoring program in
Roanoke, Virginia. This effort was
designed as a follow-up to previous
IACP studies of wood combustion
and motor vehicle emissions under-
taken in Raleigh, North Carolina;
Albuquerque, New Mexico; and
- The metals emission control ef-
ficiencies shown in Table 1 are
used to relate stack emission
rates to the amount of pollutants
in the sludge.
The regulation is now sched-
uled for promulgation in October
1991. For further information on
the incineration portion of the
rule, call Gene Crumpler, Sludge
Regulation and Management
Branch, at (202) 475-7310.
*Other methods include application
to land, distribution and marketing,
placement in monofills, and place-
ment in surface disposal sites.
* "The EPA is controlling hydro-
carbon emissions as a way of
limiting the emission of organic
pollutants present in the sludge fed
into the incinerator and that are
created during incineration.
Boise, Idaho (see related articles in
May, September, and November
1988 issues). The Roanoke effort
was intended to determine the
sources as well as the levels of am-
bient air carcinogens associated
with particle and semi-volatile com-
pounds. Mutagenic testing will be
performed on extracts of the
samples in order to select samples
IACP Completes Roanoke Air Sampling
7

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Roanoke (continued)
for use in tumor-initiating studies.
The Roanoke effort differed from
previous studies in that it investigat-
ed the impact of a third combustion
source, residential distillate oil com-
bustion (RDOC), in addition to the
sources covered in previous studies.
Roanoke was selected for this
experiment because it (1) repre-
sents a relatively simple mix of air
pollution sources, (2) is isolated
from other metropolitan areas, (3)
has a relatively high usage of
RDOC, a large number of good
monitoring sites, support of State
and local governments, and (4) is
relatively close to Research Tri-
angle Park, where the laboratory
work was being performed.
The sampling started in late
October 1988 and continued
through the first week in February
1989 at seven monitoring sites and
20 residences in the Roanoke area.
Three of the sites were classified as
primary sites (roadway, residential,
and background), and were equipped
with an array of samplers for col-
lecting particles, semi-volatiles, and
gases. The samples were collected
every 12 hours, 7 days a week,
weighed on site, and were shipped
to RTP twice weekly for chemical
and bioassay analysis. Approxi-
mately 15,000 12-hour samples
were collected and nearly 150,000
1-hour criteria pollutant and
meteorological values measured
and stored in the data system.
Each primary site consisted of
two dichotomous samplers for
determining mass loadings and
elemental composition. Other
samplers included a VOC/aldehyde
sampler using a 6-liter summa
polished canister and a dini-
trophenylhydrazine (DNPH) im-
pregnated silica gel tube, a PM-10
hi-vol for mass loadings, a 4 CFM/m
medium-vol sampler for semi-
volatiles using an XAD-II sorbent
and quartz filter, a high volume (40
CFM) virtual impactor (HVVI) for
C-14, three HVVIs for bioassay
analysis, a fine particle sampler for
determining the fraction of carbon
in the air that is volatilizable vs.
elemental, and an annular denuder
for measuring acid aerosols
(sulfates, nitrates, nitrous and nitric
acid), and ammonium ion.
At the four auxiliary sites, a
dichotomous sampler for mass and
an HVVI for bioassay analysis were
operated to provide some measure
of spatial variability within the
geographical area. In addition, 10
pairs of residences were sampled (1
pair each week for 10 weeks). One
house in the pair used distillate oil
for heat while the other used either
natural gas or electricity. Sampling
was conducted inside and outside
each house for a 4-day period (Sat-
urday through Tuesday) with contin-
uous monitoring of the stack emis-
sions of the oil burning residence.
The samples are in various
stages of analysis. While many
have been completed, others are
scheduled for completion in FY90.
Interim reports and journal articles
will be prepared when all the
analyses are completed. If you
would like additional information,
please call Alan Hoffman, EPA,
Atmospheric Research and Ex-
posure Assessment Laboratory
(AREAL) at (919) 541-1929, (FTS)
629-1929.
EPA To Begin Study of Consumer Products
"Consumer Product Com-
parative Risk: Market-based Pollu-
tion Prevention" is an OAQPS pro-
posal selected for funding to begin
in October 1990. Part of an EPA-
wide Pollution Prevention initiative,
this project will team OAQPS with
the Office of Solid Waste and other
program offices to examine what
cumulative risks - cradle to grave
- consumer goods have as by-
products. If consumers were aware
of the true environmental health
costs of alternative products, the
proposal hypothesizes, conscious
choice could influence market de-
mand. That this kind of approach
can work is evidenced by the
changes we have seen in the
marketplace as consumers have
acted on information regarding
dietary fiber, cholesterol, and
chemicals in their food.
This project plans for four pro-
ducts: a screening evaluation, a pro-
duct group risk assessment, a
report giving methodology guidance
for further assessments, and an in-
formation/education strategy.
The screening evaluation will
consist of a qualitative assessment
of a wide range of products, begin-
ning with a list of product types used
regularly at home. Each product
will then be evaluated, listing such
environmental cost considerations
as limited versus renewable natural
resource, recyclable/biodegradable,
toxic emissions/effluent, frequency
of product or disposal abuse, means
of disposal, and fate/impacts after
disposal. This evaluation will result
in a focus product type for the in-
depth risk assessment.
The focused assessment will
score the environmental cost con-
siderations of the product alter-
natives. A methodology report will
outline the procedure so that the
assessment may be used to com-
pare other product types.
The fourth product involves
developing a strategy for dissemi-
nating information from both the
qualitative and quantitative
assessments to the public. Project
developers hope that awareness of
the full costs of consumer products
will result in changes in buying and
consumption patterns.
The Newsletter will include up-
dated information on this project as
it becomes available.
8

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OAQPS Conducts Noncancer Risk Project
Historically, evaluation of risks
associated with exposure to toxic
air pollutants has focused on the
potential for a carcinogenic
response. OAQPS has conducted a
study to evaluate the potential that
adverse noncancer health effects
will result from exposure to rou-
tine emissions of toxic air pol-
lutants. Available pertinent infor-
mation was reviewed, and two
detailed assessments were con-
ducted.
Study Reviewed a Variety of Data:
Data for noncancer disease in-
cidences were reviewed as reported
by State, local, and Federal agen-
cies, along with reports of non-
cancer health effects linked with
nonoccupational exposures due to
industrial releases. These included
evaluation of case reports; State,
local, and Federal agency ex-
periences; health effects literature;
and exposure data (i.e., modeled
and monitored ambient concentra-
tions). The data demonstrated that
noncancer diseases are an impor-
tant public health concern and that
environmental factors can play a
role in disease incidence. A survey
of State, territorial, and local agen-
cies indicated that a number of air
releases are likely to occur each
year with the potential to result in
serious noncancer health effects in
the exposed population. Many
State and local air pollution control
agencies have required additional
air pollution control equipment for
sources emitting toxic air
pollutants, specifically to reduce
potential noncancer effects.
An evaluation of available ex-
posure data for toxic air pollutants
indicated that air releases of these
pollutants are widespread, but
neither a comprehensive monitor-
ing or modeling data base nor a
complete toxicity data base exist.
Biological indicators studies (e.g.,
human adipose and other tissue
samples) revealed that many
chemicals found in the atmosphere
have been detected in humans.
Although other exposure pathways
besides inhalation are expected to
contribute to the presence of these
chemicals in human tissue samples,
air exposures may be significant.
OAQPS Assessments Included
Broad Screening and Urban
County Studies:
Two qualitative assessments,
studying the potential association
between exposure to toxic air
pollutants and noncancer public
health risks, were conducted by
OAQPS for this project. Limited
and inadequate data made a quan-
titative assessment of risks im-
possible. The assessments were
conducted by comparing modeled
and/or monitored ambient concen-
trations to health reference levels
and lowest-observed-effect levels
(LOELs).
The first analysis, entitled the
"Broad Screening Study," assessed
exposure to individual or multiple
pollutants in ambient air based on
exposure data from many areas of
the country. Both health and ex-
posure data were available for less
than 10 percent of the chemicals
which have been detected in am-
bient air. For those chemicals
studied, noncancer health risks ap-
peared to be of concern. For ap-
proximately 50 percent of the
chemicals, modeled and/or
The "Report of an Ad Hoc Study
Group on Risk Assessment Presen-
tation" is the result of a one-year ef-
fort by a group of professionals in
risk analysis and management. The
document covers hazard identifica-
tion, dose-response evaluation,
exposure assessment, and risk
characterization for carcinogens as
well as the characteristics of a good
risk assessment document. It
should be useful both to those who
monitored levels exceeded health
reference levels at numerous sites
throughout the country. A smaller
percentage of sites and chemicals
indicated ambient concentrations
exceeding LOELs. These ex-
ceedences were seen with chronic
modeled concentrations and short-
term and long-term ambient
monitored concentrations. When
considering the potential impact of
exposure to chemical mixtures,
many areas and health endpoints
(e.g., reproductive/developmental
toxicity, respiratory toxicity, etc.)
indicated cause for concern.
The second analysis, entitled
the "Urban County Study," involved
a more detailed evaluation of a
midwestern industrialized urban
county. This work expanded the
number of chemicals evaluated in
the Broad Screening Study and
assessed the combined impact of
multiple emission sources versus
the impact of sources independent-
ly. Approximately 200 chemicals
from 122 point sources plus area
sources were evaluated. Health
reference levels and LOELs were
compared to the modeled pollutant
concentrations. Estimated ex-
posures exceeded the health
reference levels for long-term (an-
nual) average concentrations, long-
term maximum concentrations,
(continued on page 11)
must make risk assessments and to
risk managers who must make and
execute policy based on those
assessments. Copies may be ob-
tained from:
American Industrial Health Council
330 Connecticut Avenue, NW
Suite 300
Washington, DC 20036
Attn: Lisa Odoms
Risk Assessment for Carcinogens
Now Available
9

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norma (continued from page 1)
with petroleum-based products,
Florida may select one of a
number of techniques for remedia-
tion, according to the level of con-
tamination. Three of these techni-
ques are described below.
-	land farming - used for the least
contaminated soils. The dirt is
brought to the surface, and
spread out in a thin layer over
an impermeable liner. Con-
taminants are removed by
volitilization, biodegradation,
and photodegradation. The
State does not require a permit
before land farming begins if it
is done on site. Permits may be
required if land farming is con-
ducted offsite or if the site is
large.
-	vacuum extraction - functions
on soil comparably to the way
air stripping does for water. A
relatively new technique gene-
rally used in-situ, vacuum ex-
traction works by applying a
vacuum to a well or series of
wells constructed above the
water table in the unsaturated
zone. Air is drawn into the
wells from the surrounding
soils by the vacuum. As fresh
air is brought in, VOCs move
from the soil into the air and
are then removed by the
vacuum. The exhaust may be
vented directly to the atmo-
sphere or treated to remove
contaminants. However, the
State has a draft policy in effect
requiring emissions from the
exhaust to be treated for the
first two months of operation.
Following that, exhaust sam-
pling will be required and a
decision made (on a case-by-
case basis) on whether to con-
tinue treatment. While vacuum
extraction is too new a techni-
que for standard design equa-
tions to have been developed,
for permitting requirements the
methodology that has been
used in evaluating air strippers
can be applied, provided that
dispersion modeling is
performed.
- incineration - may be performed
in stationary units or in one of a
number of large and small
mobile units. The mobile units
use a belt feed to transport soil
into the burn chamber, which
operates within a temperature
range of 550° to 1000°F. They
are able to handle up to 10 tons
per hour (nominal rating),
depending on the soil wetness
and the amount of contamina-
tion. In some cases, after-
burners may be required. After
the dirt has been baked, one
grab sample must be taken per
batch of soil, or for every 50
tons. The samples must be ana-
lyzed by EPA Method 5030/
8020 for benzene, toluene,
ethylbenzene, and total xylene
and by EPA Method 418.1 for
total recoverable petroleum
hydrocarbons. Depending on
how clean the resulting soil is,
it may be used for clean fill (the
most stringent requirements),
roadbed or encapsulated in-
dustrial foundations, or asphalt
aggregate. In addition, the per-
mit to incinerate requires that
particulate matter emissions be
minimized during unloading,
loading, and handling of both
contaminated and decontami-
nated soils, and that soils
brought to the incinerator be
processed quickly.
While Florida's use of these
techniques to remove soil con-
taminants may have been impelled
by its concern to protect its drink-
ing water supply, the State also
recognizes the presence of a possi-
ble health hazard through inhala-
tion of these pollutants before, dur-
ing, or after remediation. Florida
plans to revise the manual it
prepared outlining requirements
for the remediation techniques
described above.
For further information, con-
tact the Florida Department of En-
vironmental Regulation, Division
of Waste Management, at (904)
487-3299.
Helpful Numbers
Air Risk Information Support Center
(Air RISC Hotline)	(919) 541-0888
(FTS) 629-0888
Control Technology Center (Hotline)	(919) 541-0800
(FTS) 629-0800
NATICH Clearinghouse Staff	(919) 541-0850
(FTS) 629-0850
SARA Title III	1-800-535-0202
10

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(continued from page 2)
Technical Findings Summarized
The project summary, published
in October 1988, summarized the
general technical findings:
-	Weather is a vital factor in the
formation of Denver's brown
cloud. Air is rarely stagnant
over Denver, even when there is
a brown cloud. Air pollution
may move down the South
Platte River Valley from Denver
as far as 60 miles to the north-
east and return to the city, often
in the same day with more aged
pollution.
-	Variations in pollution sources,
chemical reactions, weather,
and chemical concentrations
make every brown cloud
different.
-	There is no single main source
of the brown cloud. Contribu-
tions of major sources to the
brown cloud vary according to
human factors and weather
conditions.
-	During most of the winter,
Denver experiences good to ex-
cellent visibility (greater than
12 miles).
-	During poor visibility periods,
primary fine particulate emis-
sions from mobile sources and
from residential woodburning
each contribute approximately
one-quarter of the visibility im-
pairment in Denver. Dust con-
stitutes an average of 10 per-
cent of the visibility impair-
ment. The contribution of dust
to the brown cloud increases
after roads are sanded.
-	Improvement in visibility was
not found when natural gas was
used instead of coal by the Public
Service Company to generate
electricity during comparable
meteorological periods. The use
of natural gas reduced primary
emissions of the invisible gases
(sulfur dioxide and oxides of ni-
trogen), but these reductions did
not contribute to a detectable
reduction in the brown cloud.
-	The total contribution to the
brown cloud from mobile
sources, power plants, and oil
refineries cannot be determined
because their contribution to
the formation of secondary par-
ticles is not known.
Socioeconomic
Findings Summarized
The socioeconomic component
of the study examined control
strategy design, potential emission
reductions, and likely socioeco-
nomic effects for 10 strategies to
reduce the brown cloud. The
following general findings were
noted:
-	Programs including enhanced
inspection and maintenance for
gasoline and diesel vehicles,
and alternative fuels for certain
diesel vehicles could reduce
primary emissions at modest
cost to vehicle owners and
taxpayers.
-	In strategies focused on reduc-
ing residential wood-burning
emissions, findings indicated
that metropolitan area house-
holds and businesses would
face modest out-of-pocket costs
and changes in lifestyles if
wood burning strategies were
implemented.
- Several strategies targeted
emissions from coal-burning
power plants in the metro-
politan area. A fuel switch from
coal to natural gas would elimi-
nate sulfur dioxide and reduce
nitrogen oxide emissions per
plant at a significant cost to
electricity users and Colorado's
western slope coal interests.
As is the case with many
studies, the Metro Denver Brown
Cloud Study did not answer all the
questions researchers and the com-
mittee had hoped would be an-
swered. In addition, several new
questions arose from examining
the data. Currently, a second study,
Brown Cloud II (scheduled for
1991-1992), is being organized
along the guidelines of Brown
Cloud I. Once more the private
sector is financing most of the ef-
fort, although the State of Col-
orado is expected to contribute
some funding.
The EPA Region VIII repre-
sentative for the Brown Cloud II
Study is Mark Komp of the Air
Branch's Planning Section. Copies
of the 1987-1988 Metro Denver
Brown Cloud Study reports may
be obtained from the Atmospheric
Sciences Center, University of
Denver, Denver, Colorado 80208.
OAQPS
(continued from page 9)
and short-term (24-hour) concen-
trations. Results also suggested
that a larger number of pollutants
exceeded health reference levels
for short-term modeled concentra-
tions than for long-term modeled
concentrations. In general, prox-
imity to individual sources was a
significant factor in determining
risk. In a few instances, however,
the additive contribution from a
variety of sources resulted in
significant concentrations over a
broad geographic area.
A draft of the report is cur-
rently undergoing review, with a
final draft planned for the spring.
For further information, contact
Scott Voorhees at (919) 541-5348,
(FTS) 629-5348 or Beth Hassett-
Sipple at (919) 541-5346, (FTS)
629-5346.
11

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The NATICH Newsletter is published six times a year by the National Air Toxics Information Clearinghouse.
The Newsletter is prepared by Radian Corporation under EPA Contract Number 68-D8-0065, Work Assign-
ment 2-1. The EPA Project Officer is Scott Voorhees, EPA Office of Air Quality Planning and Standards,
Research Triangle Park, North Carolina 27711, Telephone: (919)541-5348. The Radian Project Director is
Caroline Brickley, P. 0. Box 13000, Research Triangle Park, North Carolina 27709, (919)541-9100.
The Newsletters distributed free of charge. To report address changes, write Meredith Haley, Radian Cor-
poration, P. O. Box 13000, Research Triangle Park, North Carolina 27709.
The views expressed in the NATICH Newsletter do not necessarily reflect the views and policies of the
Environmental Protection Agency. Mention of trade names or commercial products does not constitute any
endorsement or recommendation for use by EPA.
Printed on recycled papet
Scott Voorhees
Pollutant Assessment Branch
U.S. Environmental Protection Agency
MD-13
Research Triangle Park, NC 27711
FIRST CLASS MAIL
U.S. Postage Paid
E.P.A.
Permit No. G-35

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