United States EPA-600/9-80-043
Environmental Protection October 1980
Agency
&EPA Research and
Development
RESULTS OF RESEARCH
RELATED TO STRATOSPHERIC
OZONE PROTECTION
Prepared for
96th Congress of the United States
Prepared by
Office of Research and Development
Washington, DC 20460
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EPA-600/9-80-043
October 1980
RESULTS OF RESEARCH
RELATED TO STRATOSPHERIC
OZONE PROTECTION
Prepared for:
96th Congress of the United States
Prepared by:
Office of Research and Development
U.S. Environmental Protection Agency
Washington, DC 20460
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DISCLAIMER
This report has been reviewed by the Office of Research and Development,
U.S. Environmental Protection Agency, and approved for publication. Mention
of trade names or commercial products does not constitute endorsement or rec-
ommendation for use.
i1
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PREFACE
This report 1s submitted to Congress in compliance with Section 153(g)
of the Clean Air Act Amendments of 1977, Public Law 95-95 (PL 95-95). The
law requires that the Administrator of the Environmental Protection Agency,
as part of the program for ozone protection, shall "not later than January 1,
1978, and biennially thereafter, , . , report to the appropriate committees
of the House and the Senate, the results of the studies and research con-
ducted under this section and the results of related research and studies
conducted by other Federal agencies."
111
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CONTENTS
LIST OF FIGURES vi
LIST OF TABLES vi
I EXECUTIVE SUMMARY 1
A. Introduction 1
B. Findings to Date—An Overview .,,,,, 1
II CAUSES OF STRATOSPHERIC OZONE DEPLETION AND RESULTING ENHANCE-
MENT OF ULTRAVIOLET RADIATION 6
III POTENTIAL PRIMARY EFFECTS OF STRATOSPHERIC OZONE DEPLETION 10
A. Human Health Effects 10
1. Background , . , 10
2. Recent Research 11
a. Skin Cancer Data 11
b. NCI Skin Cancer Study 12
Materials - Old and New Data Bases . . 14
Results 16
c. Melanoma of the Skin 20
d. Case Control Studies 23
B. Nonhuman Biological Systems 26
1. Background 26
2. Current Research 28
a. Marine Organisms 28
b. Terrestrial Plants 30
3. Projections and Uncertainties , . , 32
a. Effects of UV-B on Marine Organisms .... 32
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Ill POTENTIAL PRIMARY EFFECTS OF STRATOSPHERIC OZONE DEPLETION (Continued)
b. Cancer Eye in Cattle 34
c. Terrestrial Plants 34
Direct Effects of Increased UV-B 34
Secondary Effects Due to Climate Changes, . 35
4. Future Needs 35
C. Climate Effects 38
1. Background 38
2. Recent Research 38
a. Mechanisms that Affect Climate Change 38
b. Mathematical Models 41
3. Projections and Uncertainties 41
Temperature Changes 41
4. Future Needs 42
IV FEDERAL AND INTERNATIONAL RESEARCH COORDINATION . . , 44
A. Interagency Committee on Stratospheric Ozone Protection . 44
B. United Nations Environment Program/Coordinating Committee
on the Ozone Layer 45
REFERENCES 47
vi
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FIGURES
1 Projected Stratospheric Ozone Depletion by CFC'S , , , , , 9
2 Nonmelanoma Skin Cancer Incidence in the United States
by UV-B Exposure as Calculated by Scotto 13
3 Nonmelanoma Skin Cancer Incidence in the United States
by UV--B Exposure (Annual UV-B Count x 1(T4} 18
4 Vertical Profile of Ozone Depletion by CFC's Predicted
by a One-Dimensional Photochemical Model ...,..,., 39
TABLES
1 UV-B Insolation and the Age-Adjusted Skin Cancer Incidence
Rates for Caucasians 17
2 Estimated Relative Increase in Skin Cancer Incidence
Associated with a U Increase 1n UV-B by Geographic
Location 19
3 Death Rates and Projected Death Rates from Malignant
Melanoma of Skin by Sex and Time Period 22
4 Human Health Research Needs 25
5 Losses in Aquatic Organisms ,..,..,,..,.... 33
6 Nonhuman Biological Research Needs 36
7 Climate Research Needs , , . 43
vii
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I EXECUTIVE SUMMARY
A. Introduction
Concern over the possible depletion of stratospheric ozone due to the
release of chlorofluorocarbons (CFC's), as well as by other emissions and
activities of mankind, has existed for several years. In August 1977, Con-
gress passed PL 95-95, the Clean Air Act Amendments of 1977, which includes
a mandate for EPA to undertake and coordinate federal research to ascertain
impacts of ozone depletion on public health and welfare, and human-generated
causes of such depletion. This document is the second report on federal
research required biennially under section 153(g) of PL 95-95.
B. Findings to Date—An Overview
This report emphasizes the results of EPA-supported research and re-
lated studies and presents the latest assessment and understanding of strato-
spheric ozone depletion by CFC's, as reported by the National Academy of
Sciences in November 1979 ("Stratospheric Ozone Depletion by Halocarbons:
Chemistry and Transport"), and in December 1979 ("Protection against Deple-
tion of Stratospheric Ozone by Chlorofluorocarbons"). This EPA report does
not describe all the relevant research results obtained by other federal
agencies, since Section 154 of the Clean Air Act requires them to submit
separate reports. Reports from these other federal agencies to the Congress
complement the present document. To the extent possible, their results are
integrated into this summary.
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The resulting effects of uncontrolled release of ozone-depleting
substances to the atmosphere has far-reaching implications and are not
limited to the jnited states, but are distributed globally. Many uncertain-
ties and unknowns still exist in each research area, though the NAS has
expresses , LO ^oiiLiLiSion inui it nui a 9t>,o confluence uiat existing races or
CPC emissions will result in an ozone depletion of between 5 and 28%. The
general objective of the research to date has been to reduce these uncertain-
ties, probe into certain areas where knowledge is meager, and quantify ozone-
depletion effects wherever possible.
Recent research suggests that if chlorofluorocarbon (CFC) releases were
to continue at the 1977 rate, a stratospheric ozone depletion of about 16.5%
could occur in three to five decades. This would affect the transfer of
solar energy in the atmosphere. Current capabilities to assess the impact
of such depletion on weather and climate are limited to approximate predic-
tions of globally-averaged temperature increases. (The current predicted
increase is about 0.4°C.) However, ozone depletion could also affect local
and regional weather, including precipitation. Unfortunately, lack of
knowledge on this issue limits the ability to make useful predictions.
Since the stratospheric ozone layer shields the earth's atmosphere,
surface, and waters from damaging ultraviolet wavelengths between 290 and
320 nm (UV-B), the estimated ozone depletion of 16.5% will also result in
substantial increases (about 33% for mid-latitudes) of UV-B dosages to
exposed biological systems. Therefore, much of the current research sup-
ported by EPA has focused on analyzing the effects of increased UV-B
exposures on humans and nonhuman biological systems.
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Since humans are not exposed experimentally to controlled dosages of
UV-B, assessments of the effects of UV-B exposure on human health are largely
based on demographic studies in eight regions by the National Cancer Insti-
tute (NCI), supported by EPA, using epidemiological data. The emphasis has
been on analyzing skin cancer incidence rates. The most significant nealtli
finding to date that NCI will report is that, for the United States as a
whole, a 4-fold increase in non-melanoma skin cancer rates correlates with
a 2-fold increase in UV-B radiation flux. Measurements by the National
Oceanic and Atmospheric Administration (NOAA) indicate that each 1% decrease
in ozone results in a 2% increase in UV-B radiation. Future studies will
attempt to refine the above findings and quantify the relationship between
melanoma (about 50% mortality rate) skin cancer and UV-B radiation.
Other biological (ecological) systems have been experimentally exposed
to controlled dosages of UV-B. Nevertheless, the problem of quantifying
these biological effects is enormous. Only a few major plant and animal
groups, primarily fish and phytoplankton, have been studied during this re-
porting period. In spite of this limitation, recent research leads to the
following conclusions:
o Small increases of UV-B appear to inhibit photosynthesis in
some terrestrial and aquatic plants and at least some nitrogen
fixing mechanisms.
o Plant species possess the capability for some repair of UV-B
damage when exposed to full sunlight in the visible portion of
the spectrum but this repair does not prevent significant reduc-
tions in the yields of sensitive species.
o Shifts in the composition of both aquatic and terrestrial plant
and animal communities are probable, and some of these shifts
appear likely to significantly damage commercial fisheries.
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It can thus be stated that an increase of UV^B radtatton at the
earth's surface resulting from stratospheric ozone depletion would probably
have ecological impacts. However, there is a lack of means to assess
and predict the sensitivity of various ecological systems to increased
UV-B radiation. Further effort is necessary to quantify such sensitivity
before social and economic impacts can be estimated.
Improved instrumentation and monitoring are vital to research on ozone-
depletion impacts. A portion of the funds available for this research
has been spent on development of (1) improved UV-B sources and
instrumentation, (2) additional UV-B monitoring, and (3) analysis of the
resulting data base. A small portable personal dosimeter has been developed
and delivered for use in health effects research in order to better quantify
the exposure of individuals to UV-B radiation in contrast to measuring the
UV-B radiation flux to a geographic location. In an effort to improve the
accuracy of a variety of UV-B sources and detectors, the National Bureau of
Standards (NBS) has established a quality-assurance procedure (and is out-
fitting a laboratory) that will ultimately reduce measurement errors to less
than 10%. {Currently these range as high as 45%.)
Additional UV-B monitoring (Item 2, above) was undertaken by NOAA at
the key epidemiological locations, as identified in the NCI skin cancer
studies. Under Item 3, above, analysis of existing NOAA data has resulted
in a verification that the ratio between UV-B enhancement and ozone depletion
is very close to the theoretically predicted value of 2 (i.e., a 2% increase
in UV-B for every 1% decrease in ozone).
Again, it is emphasized that more data and research are needed to reduce
further the uncertainties associated with estimation of impacts caused by
ozone depletion.
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C. Future Research Needs
A potential for significant adverse environmental effects has been
suggested by research accomplished to date. Examples are skin cancer inci-
dence, effects on larvae of commercially important fishes, marine organisms
such as phytoplankton and zooplankton, and certain plants used as food. More
data are needed in all areas (i.e., human health, other biological/ecological
systems, climate monitoring, economics, and social issues), The general
research requirements are outlined here.
Research needs are separated into short-term and long-term programs.
Short-term programs are those that will return substantial quantitative
knowledge within a one- to three-year period. The longer-term research
program objectives are to broaden the base of knowledge and further reduce
uncertainties and to identify and quantify the direct and indirect effects
of ozone depletion on human health, and ecological, geophysical and socio-
economic systems.
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II CAUSES OF STRATOSPHERIC OZONE DEPLETION AND RESULTING
ENHANCEMENT OF ULTRAVIOLET RADIATION
A multitude of theoretical and experimental research and monitoring of
stratospheric chemical and physical processes and constituents has been and
is being conducted nationally and internationally. Such studies during the
two-year period (1978 and 1979) covered by this report have especially in-
creased our knowledge on the subject of the impact of man's activities,
particularly the release of CFC's, on stratospheric ozone. The National
Aeronautics and Space Administration, National Oceanic and Atmospheric
Administration, Department of Transportation, National Science Foundation
and the Environmental Protection Agency are the government agencies princi-
pally supporting such atmospheric studies. The other agencies are reporting
their activities separately to the Congress 1n accordance with Section 154
of the Clean Air Act Amendments of 1977.
The evaluation of those research findings and their implications are
presented in two reports just completed by the National Academy of Sciences
(NAS) after a lengthy and detailed analysis and assessment. The NAS effort
was contracted by the EPA, in accordance with Section 150 of the Clean Air
Act Amendments of 1977. The reports (enclosed) are titled "Stratospheric
Ozone Depletion by Halocarbons: Chemistry and Transport" and "Protection
against Depletion of Stratospheric Ozone by Chlorofluorocarbons."
The report "Stratospheric Ozone Depletion by Halocarbons: Chemistry
and Transport" concerns itself with: Sources of Stratospheric Chlorine;
Atmospheric Chemistry; Atmospheric Transport; Inactive Sinks and Their
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Assessment; Global Ozone Observations; Atmospheric Measurements; Theoretical
Models of the Stratosphere; Ozone Change Projections; and The Treatment of
Uncertainties.
Its principal findings are:
o There is agreement with previous reports that continued
release of halocarbons into the atmosphere will result in
a decrease in stratospheric ozone.
o New values for some of the chemical rate coefficients have
increased the predicted ozone reduction resulting from con-
tinued release of chlorofluoromethanes (CFM's),
o The most probable value calculated for the eventual ozone
depletion due to continued release of CFM's at the 1977
level is 16.5 percent. This value is obtained from the
value of 18.6 percent calculated from the computer model
by allowing for possible tropospheric sinks for CFM's and
for the effects on stratospheric chemistry of the CFM
greenhouse effect.
o There have been considerable improvements in the computer
models and in the laboratory and atmospheric measurements,
which have reduced the uncertainty range.
o Although there are a few exceptions, the comparison between
the models and measurements of substances in the present
stratosphere is considered to be satisfactory within the
uncertainties of the measurements. We therefore believe
that the projections for ozone depletion are valid within
the stated uncertainty ranges.
o The uncertainties in the chemical rate coefficients, in
atmospheric transport, and 1n the use of one-dimensional
models have been combined to give an overall uncertainty
range of a factor of 6 within a 95 percent confidence level,
o The uncertainty range means that for the case of continued
release of CFM's at the 1977 level there is 1 chance in 40
that the ozone depletion will be less than 5 percent and
1 chance in 40 that 1t will be greater than 28 percent,
o Even allowing for the best professional judgment of the
possibility that some important chemical reaction has been
overlooked or that there remain large errors In the
measured chemical rate coefficients, we believe that there
is a 3 out of 4 chance that continued release of CfM's at
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the 1977 level will result in an ozone depletion that
lies in the range of 9 to 24 percent.
o If the rapidly increasing use of F-22 (CHFoCl) and
methyl chloroform (CH3CC13) continues unabated, the
release rates and atmospheric behavior of these com-
pounds will require careful attention. However, since
chemical reactions remove appreciable fractions of
these compounds before they reach the stratosphere,
substitution of F-22 for F-ll (CFC13) and F-12 (CF2C1?)
would be beneficial.
o It is unlikely that direct measurements of the average
global ozone amount would permit detection of a decrease
of less than 5 percent attributable to human activity.
Total cessation of CFM release at the time of detection
would result in a decrease of ozone of about 7 percent
some 15 years later.
The report "Protection against Depletion of Stratospheric Ozone by
Chlorofluorocarbons" concerns itself with two important topics: (1)
Causes and Effects of Stratospheric Depletion (including Nonhuman Biological
Effects; Human Health Effects; Climatic Impact of Stratospheric Change; and
Biologically Effective Ultraviolet Radiation); and (2) Alternatives for
the Control of Chlorofluorocarbon Emissions and Options for Their Implementa-
tion (including International Aspects; Feasibility, Costs, and Impacts
of Technological Alternatives; Regulatory and Socioeconomic Considerations;
Technological Possibilities for Reducing CFC Emissions from Mobile Air Con-
ditioning; Technological Possibilities for Reducing CFC Emissions from
Plastic Foams; and Summary of Three Benefit-Cost Studies),
The NAS projected stratospheric ozone depletion by CFC's into the next
century is presented here for elucidation (Figure 1). This projection,
for several emission rate scenarios, when coupled with worldwide usage
characteristics (the U,S, share of world CFC production/emission approximates
31%), indicates the global nature of the protection of stratospheric ozone.
8
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0
-2
-4
-«
-8
o" -10
* -16
-18
-20
-27
-24
-26
I I I I I I l\ I
1060 70 60 90 2000 10 20 30 40 CO CO 70
YEAR
Ozone reduction for various scenarios: A,
constant release rate at the 1977 value; As, steady-state
value = -18.6%; A1, constant release rate at the 1977
value, same as A but multiplied by a factor of 0.89 to
correct for feedback effects and the possible existence
of a tropospheric sink; B, 1977 release rates until 1983,
from then on reduced by 25%; BS, steady-state value -
-14.9%; Cf 1977 release rates until 1983, reduced by 25%
until 1988, reduced an 'additional 25% after 1988; Cs,
steady-state value » -10.6%; D, 1977 release rates until
1980, increasing by 7% per year until 2000, then constant
release rate at the year 2000 value; Ds, steady-state
value » -56.7%I
FIGURE 1 PROJECTED STRATOSPHERIC OZONE DEPLETION BY CFC'S
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Ill POTENTIAL PRIMARY EFFECTS OF STRATOSPHERIC OZONE DEPLETION
A. Human Health Effects
1. Background
It has long been accepted among physicians that there is a clear
relationship between non-melanoma* skin cancer and sunlight exposure. These
cancers were typically seen in light-skinned individuals who spend consider-
able time outdoors (for example, sailors and farmers). These cancers were
also known to be rare in blacks. Attempts have been made to quantify this
relationship—such as the calculation of annual incidence rates for locations
at different latitudes—because:
o The relationship was so obvious that preventive measures
could be justified, even in the absence of quantification.
o It is more difficult and tedious to calculate incidence rates
for non-melanoma skin cancer than it is for other cancers,
including melanoma. Most patients with the former disease
do not require hospitalization and do not die from the disease.
Therefore, in order to count every new case of this disease
in a defined geographic area, cooperation of all physicians
in that area (and nearby areas) is needed. This is consider-
ably more difficult and tedious than obtaining the cooperation
of the administrators of the much smaller number of hospitals
in these areas and supplementing this information with a
search of death certificates.
o While virtually all (98 - 99%) non-melanoma skin cancer cases are
not fatal, the routinely available mortality rates cannot be
used as a substance for incidence rates. In addition,
death certificates listing non-melanoma skin cancer as the
cause of death were often inaccurate (Dunn, et al_,, 1965).
*While virtually all of these cancers are either basal or squamous cell
carcinomas, any type could be referred to as carcinomas of the skin. How-
ever, this "non-melanoma" terminology is prevalent in the literature and
therefore is used in this report.
10
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Even before concern about ozone depletion arose, exposure to sun-
light had been widely suggested as being a cause of melanoma because simi-
larities with non-melanoma skin cancer were so striking (although this re-
lationship was not completely accepted). Lancaster (1956) was the first of
many investigators to demonstrate that risk of melanoma increased as the
equator was approached. He also was the first to conduct a case control
study of melanoma (Lancaster and Nelson, 1957). Several case control
studies have found that individuals at high risk had fair complexions and
also spent a lot of time outdoors. However, these studies are unlikely to
have explained the consistency of these conclusions because, of problems in-
herent in the study design. European immigrants to Israel before 1948 have
been found to have higher age and sex specific incidence rates than more
recent European immigrants (Movshovltz and Modan, 1973). While some curve
fitting of the data has been done, this Information was used primarily as
evidence that sunlight was involved 1n the etiology of melanoma rather than
to determine a dose-response relationship.
2. Recent Research
a. Skin Cancer Data
Renewed Interest 1n quantifying the risk of non-melanoma and
melanoma skin cancer with exposure to ultraviolet was stimulated by the con-
cern about ozone depletion. Establishment of a dose-response relationship
is necessary 1n order to determine how many additional skin cancers could
be predicted to occur as a result of predicted ozone depletion and resulting
Increased ultraviolet exposure and to support an Integrated assessment for
regulatory decisions.
11
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In a determination of the dose-response relationship for the
disease, several response measures are available, including:
o The incidence rate (the number of new cases of disease per
unit population per unit time). For melanomas, these rates
are available for 9 locations from the 3rd National Cancer
Survey and are also available from Cancer Registries, includ-
ing those participating in the Surveillance Epidemiology and
End Results (SEER) Program. For non-melanoma skin cancer,
NCI under EPA funding has calculated incidence rates at
eight of the SEER locations (Scotto, 1979a). Previously,
Scotto, et. al_. (1974) computed incidence rates at four
TNCS locations. Both these data are plotted in Figure 2
(from Scotto, 1979). One Cancer Registry (Waterhouse, et a!.,
1976) claims to collect all newly-diagnosed non-melanoma
skin cancer in their defined geographic area. They also
publish these rates.
o The point prevalence rate (number of cases per unit population
at a point in time). These are available for many locations
—principally through the Health and Nutrition Examination
Survey (HANES)--but the numbers for melanoma are quite small.
o Mortality rates (number of deaths per unit population per
unit time). These rates have been available for the entire
country for over 45 years, but most of the published sources
do not have separate mortality rates for melanoma and non-
melanoma skin cancer. Mason and McKay (1974) have published
age-adjusted mortality rates for each of these cancers for
each county for the years 1950 through 1969 combined. They
conclude that both sexes show a "striking southern predomi-
nance extending from coast to coast."
For a determination of the economic impact, incidence rates
would be the most useful response measure. For melanoma, the incidence rate
offers a good approximation of this response measure because it is unusual
for an individual to develop two independent melanomas in his lifetime.
However, occurrences of non-melanoma skin cancer in the same individual
are relatively common. So for this disease, the response measure would have
to be calculated directly.
b. NCI Skin Cancer Study
EPA provided funds to the National Cancer Institute in support
12
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500
400
O
E 300
a.
2
8
oc
UJ
a.
ju 200
100
ALBUQUERQUE. NEW MEXICO "ANGLO1;
ATLANTA •
DALLAS-FT. WORTH D /NEW ORLEANS
SALT LAKE CITY, UTAH
MINNEAPOLIS
•
SEATTLE
X
SAN FRANCISCO-OAKLAND
HINNEAPOLIS/
• X
DETROIT /
/ D
X IOWA
I
I
I
I
1.0
1.2
1.8
1.4 1.6
ANNUAL UV-B COUNT X 10**
• NCI/EPA 1977-78
D — — — TNCS 1971-72
SOURCE: Scotto.19.79
Figure 2 . Nonmelanoma skin cancer incidence in the United States by UV-B exposure
as calculated by Scotto.
Adjusted for New Mexico "Anglos"
2.0
13
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of research directed at estimating the human health effects of strato-
spheric ozone depletion. Specifically, the NCI was asked to conduct skin
cancer incidence surveys in various geographic locations with the United
States, and to provide more reliable estimates of the dose-response relation-
ship of UV-B and skin cancer development among American Caucasians, Results
from NCI's earlier investigations were consistent with the hypothesis that
increased amounts of UV-B radiation lead to increased incidence of skin
cancer. Estimates of the dose-response relationship indicated that for most
locations a one percent increase in UV-B would eventually result in an ap-
proximate two percent increase in skin cancer incidence. This factor of two
had been challenged because of the paucity of epidemiologic information
available for evaluation. NCI's task was to reduce the uncertainty in this
estimate.
Materials - Old and New Data Bases
Earlier, NCI provided skin cancer morbidity data from four loca-
tions (covering a six-month survey period of September 1, 1971 through
February 28, 1972),
Location Degrees N. Lat.
Minneapolis-St. Paul 44,9
Iowa 42.5 (Des Moines)
San Francisco-Oakland 37.8
Dallas-Ft. Worth 32.8
Currently, eight population-based Incidence surveys have been
conducted (covering a 12-month survey period of June 1, 1977 through May 31,
1978).
14
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Northern
Latitudes
Middle
Latitudes
Southern
Latitudes
Location
Seattle (King Co.)
Minneapolis-St. Paul
Detroit
Utah
San Francisco-Oakland
New Mexico
Atlanta
New Orleans
Contractor
Fred Hutchinson Cancer
Research Center
Degrees N. Lat.
47.5
University of Minnesota
Michigan Cancer Foundation
Utah Cancer Registry
44.9
42,2
40.7
(Salt Lake City)
California Tumor Registry 37.8
New Mexico Tumor Registry 35,1
(Albuquerque)
33.7
Emory University
Tulane University
30.0
All but one location (Minneapolis-St. Paul) in the new survey be-
long to NCI's main cancer (SEER) program. Attaching this special study to
the SEER Program quickly assured the best available, active cancer registry
program on a national level. Morbidity from other malignancies could also
be measured and compared directly with non-melanoma skin cancer incidence
in these locations. For the short-term effort, this cancer reporting net-
work provided immediate access to physicians and other sources seeing and
treating skin cancers.
The new locations span 17.5 degrees north latitude and a UV-B
ratio of 2:1 from south to north. Two locations, San Francisco and
Minneapolis, will provide bases for establishing trends in incidence, In
collaboration with Census Bureau demographers, population estimates were
derived specifically for each location for December 1, 1977, the midpoint
of the latest survey period. Better population estimates will be available
after the 1980 census,
15
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It is recognized that the solar ultraviolet measurement is not the
only factor to consider in evaluating variations in skin cancer incidence
among population groups. Specifically, to what degree do host (e.g., genetic)
factors or environmental factors influence the development of disease?
Racial groups, such as Blacks and Orientals, and ethnic groups, such as
Hispanics are rarely, if ever, affected by this disease. Environmental
exposures other than solar UV-B, (e.g., ionizing radiation, oils, coal tar,
industrial chemicals, etc.) have been associated with the development of this
disease. In this report, we are adjusting only for the ethnic group known
as "Anglos", i.e., Caucasians other than Latin, in Albuquerque, New Mexico.
At a later date we will incorporate epidemiological data, relative to outdoor
exposure, ethnicity, industrial exposures, ability to tan/sunburn, etc.,
into the analytical models.
Results
Table 1 shows the latest information on annual UV-B insolation and
the age-adjusted non-melanoma incidence rates for Caucasians. It is clear
that populations with high possible exposures to UV-B also have high levels
of skin cancer development. Figure 3 shows these points. The data are
plotted on a semi-log scale so that a straight line with a positive slope
represents a constant percentage increase in responses.
Assuming that annual UV-B flux increases by one percent at each
location, and applying the results of this model to the new data bases,
estimates of the relative effects on non-melanoma incidences were calculated
(Table 2). The model implies that Caucasians residing in areas of high UV-B
exposure may be most affected, Thus in a northern location, such as Detroit,
a 1% increase in UV-B may result in a 1.4% increase in skin cancer incidence,
16
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Table 1
UV-B INSOLATION AND THE AGE-ADJUSTED SKIN
CANCER INCIDENCE RATES FOR CAUCASIANS
Annual* UV-B
Location Count x 10~4
Seattle
Minneapolis
Detroit
Iowa
Salt Lake City
San Francisco
Atlanta
Dallas
New Orleans
Albuquerque (Anglo)
101
106
no
125
147
151
160
161
176
197
Skin Cancer Incidence Rates Among Caucasians
Age Adjusted (1970 US)/100,000/Yr.
1977-78 (S.E.) 1971-72 (S.E.)
188.7
193.3
135.6
299.3
213.0
393.8
384.2
504.1
(4.0)
(3.3) 150.9
(2.0)
123.7
(6.5)
(2.6) 183.6
(6.1)
379.3
(7.1)
04.9)
(4.3)
(2.7)
(3.6)
(6.6)
The annual UV-B counts are from preliminary monthly averages provided by
Daniel Berger of Temple University. NOAA will soon provide the detailed,
hopefully, final counts for 1977 and 1978.
Note: S.E. refers to the Standard Error of the given incidence rate, per
100,000 population.
17
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500
400
cc
o
o
o
o
cc
Ul
o.
UJ
CO
300
0200
Ul
100
Model:
(Assumes common slope)
c
o
a
c
c
i
J_
n
|
O
o
i
s •*
I I
* s
< 5
11
I
I I
100
120
140
160
180
200
ANNUAL UV-B COUNT X 10'
O
NCI/EPA 1977-78
«_TNCS 1971-72
FIGURE 3 NONMELANOMA SKIN CANCER INCIDENCE IN THE UNITED STATES BY UV-B
EXPOSURE (ANNUAL UV-B COUNT X 1(H)
18
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Table 2
ESTIMATED RELATIVE INCREASE IN SKIN CANCER INCIDENCE.
ASSOCIATED WITH A 1%'INCREASE IN UV-B BY GEOGRAPHIC LOCATION
Location
Seattle
Minneapolis
Detroit
Iowa
Salt Lake City
San Francisco
Atlanta
Dallas
New Orleans
Albuquerque (Anglo)
Annual UV-B
Count x 10'^
101
106
no
125
147
151
160
161
176
197
Lower Limit
0.63527
0.66682
0.69207
0.78682
0.92593
0.95125
1.00823
1.01456
1.10961
1.24283
Estimated
% Increase
1.31590
1.38149
1 .43400
1.63113
1.92095
1.97373
2.09260
2.10581
2.30425
2.58271
Upper Limit
2.00114
2.10124
2.18139
2.48252
2.92578
3.00657
3.18860
3.20885
3.51300
3.94032
19
-------
while in a southern location, such as Atlanta, the relative increase in skin
cancer may be greater than 2%.
While these point estimates are slightly smaller than those derived
using only the four locations of the earlier NCI survey, the degree of re-
liability has indeed improved. As an example, the point estimates and con-
fidence intervals for Iowa and Dallas-Ft. Worth are:
Iowa (42.5° N. Lat.) Dallas-Ft. Worth (32.8° N.Lat.)
4 Area Survey New Data Bases 4 Area Survey New Data Bases
Only (10 Areas) __ Only (10 Areas)
Percent change in
Incidence for 1% 2,35 1.63 3.05 2.11
Increase in UV-B
Confidence
Interval -2.78 to 7.77 .78 to 2.48 -3.57 to 10.12 1.01 to 3.21
Finally, it should be noted that more locations, in both northern
and southern zones, are needed to further refine the dose-response esti-
mates. It is hoped that the additional epidemiologic data from the sample
survey, when incorporated into the analyses of the new data bases, will
further clarify the role and importance of host factors and environmental
factors other than solar ultraviolet.
c. Melanoma of the Skin
The age-adjusted death rates from melanoma have increased
from 1951 to 1975 by about 3% per year in the population of England, Wales,
and Canada, and the white population of the United States. Lee, et al.
(in press) have shown that this increase is due to the large Increases
in risk because of changing social customs of exposing more of the body
with successively later years of birth (birth cohorts).
20
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Apparently any effects of earlter diagnosis or improved treatment within
the period 1951-1975 have not been sufficient to alter these trends. Lee,
et al_. calculated the projected course of future mortality rates of malig-
nant melanoma (Table 3). While these projections are not explicitly exposure
dependent, they provide a basis for projecting future melanoma mortalities
assuming future changes in UV intensity, life styles and other factors are
consistent with past changes.
Green (1978) evaluated the age-exposure equations developed
by Fears, ejt aj_, (1977) to determine if reciprocity holds for melanoma and
non-melanoma incidence rates. The property of reciprocity implies that
the cumulative risk to a homogeneous population of equal age can be expressed
as a product of age (i.e. time of exposure) times UV flux. This property is
important both in the establishment of dose-response relationships and in
the evaluation of potential effects of increased UV exposure. Green suggests
that reciprocity may be valid in the case of melanoma, but violated for non-
melanoma. Other experimental data indicate that reciprocity does hold for
non-melanoma. Moreover, the results suggest that the greater occurrence of
non-melanoma in the older population is not just the result of accumulated
UV doses, but that aging itself and UV radiation may be synergistic; alter-
natively, this greater occurrence could be due to a birth cohort effect,
or combination of the above effects.
All dose-response methods provide in some way for UV, sex,
and age, and are estimated for the "white" population only, A number of
other factors may be, and in some cases have been, included, Scott and Straf
(1977) report trying solar radtation, urbanicity, microclimate, proportion
of white population th.at is fair-skinned, access to medical care, economic
level of the locality, and access to melanoma clinics.
21
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Table 3
DEATH RATES AND PROJECTED DEATH RATES
FROM MALIGNANT MELANOMA OF SKIN
BY SEX AND TIME PERIOD
Time
Period
1951-1955
1956-1960
1961-1965
1966-1970
1971-1975
1976-1980*
1981-1985*
U.S. White Population
Males
14.5
16.6
19.9
22.9
26.3
28.7
33.5
Females
11.2
12.6
13.8
15.4
16.5
17.7
18.8
Source: Lee &.aL (in press).
Note: Rates are given per million per year, age-adjusted
using the UICC standard European Population.
'Projected values.
22
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They conclude that temperature and pigmentation play a role in skin cancer,
but that UV flux is the most important factor. In an analysis of skin can-
cer and solar keratosis data from Queensland, Australia, Sllverston and
Searle (1970) found susceptibility to sunburn to be an important prediction
variable. Other variables evaluated were sex, age, complexion, eye color,
ancestry, occupation, clothing habits, and residential district. More re-
cently, Vitaliano (1978) used logistic regression to estimate the relative
risk of U.S. basal and squamous cell carcinoma for such factors as cumulative
lifetime solar exposure, age, complexion, and tannability. A linear effect
for the relative risk of cancer versus exposure was found. Tannability was
shown to be a more important risk factor than complexion.
d. Case Control Studies
The National Cancer Institute and the Massachusetts General
Hospital are each conducting a case control study quantifying skin cancer
risk for individuals with different physical characteristics and life styles.
The NCI investigators are selecting a systematic sample of their series of
incident cases and a random sample of the general population for non-
melanoma skin cancer (Scotto and Fears, 1978). In a separate study, the
Massachusetts General Hospital group is studying newly-diagnosed melanoma
patients and their best friends of this age who are living in the same
neighborhood.
Both case control studies rely on questionnaires to obtain
information on physical characteristics and sunlight exposure for each
subject. While the questionnaires for the two studies differ, similar items
of information are being ascertained for both. These include history of
time spent outdoors at different times during the subject's life, hair and
23
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eye color, history of skin conditions, occupational history, ethnicity,
skin color, and ability to tan. Appropriate analysis to reflect the months
of data collection has not yet been carried out by NCI and the Massachusetts
General Hospital investigators, so their study findings are also not avail-
able at the time of this report.
3. In Table 4 we briefly summarize research areas in need of further
effort in order to refine the relationship between skin cancers and ultra-
violet radiation. In this table, we distinguish between short and long-
term programs. Short-term programs are those that will return substantial
quantitative knowledge within a 2 to 3 year period and are required as a
scientific basis for regulatory decisions. Long-term research is needed
in order to broaden the base of knowledge and further reduce the uncertain-
ties in order to refine the scientific basis for regulatory decisions.
The first three short-term items in Table 4 consist of continua-
tions of current research. The third item identifies a research need to
provide better linkage information between ultraviolet exposure and the risk
of disease. Long-term epidemiologic studies which use direct measures of
ultraviolet exposures (i.e. dosimeters) are required if we are to refine
the relationship between skin cancer and ultraviolet. Finally, studies on
nonhuman systems are needed to provide knowledge concerning the mechanisms
of skin cancer induction.
24
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Table 4
HUMAN HEALTH RESEARCH NEEDS
Need
Research Method and Purpose
Benefits
Epidemiological data analysis
UV Radiation monitoring
Personal dosimeters
Data on nonmelanoma
skin cancer
Identify high-risk groups
Animal and cellular research
Continue the analysis of existing morbidity and
mortality data to quantify the relationship
between ozone depletion and skin cancer.
Continue the Robertson-Berger network
at key epidemiological locations. Cor-
relate data with epidemiological effects
and dosage measurements.
Develop, test, and deploy personal
dosimeters. Correlate data with other
indicators of personal dose (i.e., question-
naires, latitude, and Robertson-Berger
measurements).
Collect data in order to calculate
incidence rates for nonmelanoma skin
cancer in defined geographic areas.
Determine the effect of other factors
and calculate risk of specific exposures
by conducting case-control and other
epidemiologic studies of both melanoma
and non-melanoma skin cancer.
Conduct studies to acquire basic information
on the mechanism of skin cancer induction.
Short-term
Short-term
Short-term
Long-term
Long-term
Long-term
25
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B. Non h uma n B i o 1 og ica1 Systerns
1. Background
Data collected under the SIRA program give cause for concern
with respect to losses in fisheries and many crops. There is also a
largely unexplored potential for adverse interactions with pathogens, pollu-
tants, and drought.
The potential for losses in oceanic fisheries lies both in the
adverse effects of UV-B on the survival of larvae of the fisheries them-
selves and in the adverse effects of UV-B on the invertebrates upon which
these fish feed. Too few fish and invertebrate species have been examined
to reliably assess the potential losses which can be expected. Some fish
and invertebrate species of commercial significance suffered 50% or greater
increases in mortality when exposed to a 40% increase in the DNA-weighted
intensity of UV in the laboratory (Hunter et_al_.» 1979). This can be argued
to be a "worst case" estimate given the uncertainties in the number of species
which will be this sensitive, the degree to which the mortality increases
will be offset by more rapid growth of the survivors, the extent to which
significant segments of the population will be sheltered by remaining suf-
ficiently far below the surface, and the extent to which resistant species
can substitute for sensitive species. Nonetheless, these data are cause for
significant concern.
Studies of effects on mammals other than man have been limited to
research on an eye disease in cattle known as cancer eye (ocular squamous
cell carcinoma). Analyses of latitudinal gradients in the prevalence of
cancer eye are suggestive of a causal tie to sunlight intensity, but this has
not been demonstrated. Unquestionably, the percentage of cattle rejected at
26
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the slaughter houses due to the occurrence of cancer eye has doubled over the
past twenty-five years (Kopecky, e_t ajL, 1978), However, thts may reflect
changes 1n inspection standards, or possibly unknown factors of recent intro-
duction.
Lack of pigmentation concurrent with the absence of hair, feathers
or scales (and hence exposure to highly sensitive surfaces) appear to be
limited to man, his domesticated animals, and juvenile organisms not normally
exposed to sunlight. Therefore, it is unlikely that skin cancers or cancer
eye will be common in wild animals.
Field studies of the sensitivity of crop plants have been incon-
clusive, but roughly half of the 82 crops examined in a major survey using
controlled environments in the laboratory suffered at least a 5 to 25% re-
duction in growth when exposed to UV-B (Briggs and Kossuth, 1978). An ad-
ditional fourth suffered more than 50% growth reductions. These labora-
tory results overestimate the impact of UV-B in the field where adapt-
ability mechanisms, not yet identified, reduce the impact of UV-B.
Impacts on noncrop plants have received little attention. The
data obtained for tree and shrub seedlings of commercial significance
suggest that these species will tend to be relatively resistant, but
these data must be used with caution (Kaufmann, 1978). They are based
on very brief observations and it is quite possible that expression of
effects will be delayed in some of these plants. Moreover, effects may
be marked by the naturally occurring variations among individual plants.
In brief experiments with such slowly growing spectes arid small sample
27
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sizes, considerable periods may be required for changes in growth rates
due to UV-B irradiation to be demonstrable.
Interactions among pathogens and crops were partially examined in
the first year of the SIRA program, but the potential significance of such
interactions is still unclear. Initial experiments showed some significant
reductions in the incidence and severity of diseases, at very high UV-B
intensities (Cams, e£ al_,, 1979).
2. Current Research
a. Marine Organisms
Research, during the latest biennial period of the SIRA
program, emphasized the marked impacts on marine foodchains which were noted
in the first year's research. The three programs funded in 1978 and 1979
focused on the potential risks to marine fisheries: a study of the effects
of UV-B on anchovy and mackerel larvae; a study of effects of UV-B on crabs,
shrimp, and other invertebrates; and an assessment of the penetration of
ocean waters by UV-B. These studies, and a closely related study of the
effects of UV-B on zooplankton, funded by NASA, cover representative species
of commercial significance, the food chains sustaining these commercial
species, and the potential for exposure of organisms as a function of the
depth and the water types.
The fisheries studies, conducted by J. R, Hunter at Scrlpps,
focused upon the Pacific mackerel and the northern anchovy, species whose
larval forms.are respectively restricted to the surface waters of the ocean
28
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and distributed throughout the upper, mixed layer of the ocean. Of the two,
the anchovy, which is unpigmented and is found over a depth range associated
with considerable variation in the intensity of UV-B, Is the more sensitive.
Existing UV-B intensities (105 J nf2, DNA-weighted) represent about twice
those required to either significantly retard growth after 12 days exposure
(44 J m~2) or cause 50% mortality (56 J nT^). Laboratory experiments indi-
cate that exposure of anchovy larvae to UV-B levels which would follow a
13-25% reduction in the ozone layer (141-190 J nr2) would kill almost all of
the larvae after 12 days, reducing survival by roughly half relative to
present levels (Hunter and Taylor, 1978). However, these estimates of mor-
tality are conservative since many of the anchovy survivors appear to have
suffered brain damage which impaired the ability of the larvae to feed.
Thus, many of the survivors might not survive to sexual maturity even if
exposed to no more UV-B. In addition to increased probability of starvation,
these slowly growing survivors would be more vulnerable to predators due to
the delayed growth, which for fishes generally also means a delay in the age
of first reproduction. This demographic parameter influences the birth rate
of the population perhaps more than any other parameters.
While implications of Hunter's data are gloomy, they are
tempered by the fact that some fraction of the anchovy population exists at
sufficient oceanic depths to be protected from enhanced UV^B. Although the
size of this fraction is unknown, the fact that the anchovy larvae are very
sensitive to current levels of UV-B and lack protective pigments suggest that
29
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the fraction which is unexposed is substantial. Thus, the prognosis based
on effects on the fish themselves is unclear. The effects are strong enough
to warrant great concern and further study, but the chief uncertainty lies
in the estimation of the dose which these species will receive, not in the
estimation of the consequences of a given dose.
Experiments with individual commercially important species of
crabs and shrimp and with food chains supporting marine fisheries, essential-
ly parallel the fish experiments (Damkaer, et al_., 1978). The current levels
of UV-B radiation are harmful near the end of the normal period of larval
development and may indeed be a significant factor in determining the season-
alty of development. A 20% reduction in stratospheric ozone concentrations,
representing an increase of about 40% UV-B, would definitely reduce the
«
length of the period favorable to larval development; it is not clear that
commercially significant populations would survive with these drastically
shortened periods for reproduction. Responses of important invertebrates
within oceanic foodchains which sustain commercial fisheries respond similar-
ly (Damkaer, £t aj[., 1978), and freshwater phytoplankton exhibit statistical-
ly significant reductions in productivity, chlorophyll content, and species
composition after five weeks exposure to current levels of UV-B radiance
when compared with unirradiated controls (Van Dyke and Worrest, 1978). As
in other experiments, it is difficult to elicit quantitative predictions
from the researchers, although there is agreement that the data are suf-
ficient to warrant concern.
b. Terrestrial Plants
Studies by Caldwell (1979) at Utah State University-
partial ly supported by the SIRA program—explored mechanisms by which
30
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ultraviolet radiation affects higher plants and the degree to which plants
might be able to adapt to increased UV radiation. These studies included
measurement of biologically effective solar UV-B radiation over a natural
latitudinal gradient from the Andes to Alaska and assessment of plant optical
properties along this gradient. This study showed that plants growing in
naturally high UV radiation environments (environments in which the UV flux
is already higher than that anticipated to occur at temperate latitudes 1f
ozone reduction occurs) possess effective screening mechanisms by which the
potentially damaging UV radiation is largely shielded from reaching the
internal parts of a leaf. This does not suggest that all species of plants
will be able to adapt in this manner, nor does it mean that species growing
in tropical latitudes under a naturally high UV radiation environment could
adapt to still higher intensities. Nevertheless, the fact that many plants
can exist in naturally more intense than average UV radiation environments,
including many that were previously taken from temperate latitudes, does
complicate the assessment of potential consequences of ozone reduction on
land vegetation.
Several physiological mechanisms by which ultraviolet radia-
tion can affect plants have been investigated recently in the laboratory of
Caldwell. These Included studies of the effects of this radiation on the
plant phytochrome system, certain plant hormones, and how this radiation
stress can interact with other common stresses in the plant environment
such as mild water stress or the stress of competition with other plants.
Many stress interactions have become apparent In this research. These
studies again demonstrate the complex nature of assessing consequences of
ozone layer reduction on plants in both agricultural and wild land systems.
31
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Studies of the basic mechanisms may, however, help to eliminate the need for
extensive screening programs that are both costly and extremely time-
consuming.
3. Projections and Uncertainties
Estimated effects of ozone depletion on nonhuman systems cannot be
summarized in a concise way because of the numerous types of species in-
volved and their particular sensitivities to UV-B radiation. Research has
been performed on only a limited number considered important economical-
ly. As stated in Section III.B.I, research has been conducted on about
eighty varieties of land plants, several types of fish, but only a few non-
human animals (primarily cancer eye in cattle). (It should be noted, however,
that hairless mice are used effectively to study the production of skin
cancers by UV-B radiation.) Therefore, our approach to summarizing this re-
search is restricted to the particular species involved.
a. Effects of UV-B on Marine Organisms
Based on the literature and direct communications with re-
searchers concerning their laboratory experiments, we prepared a summary
table (Table 5) projecting the loss of productivity due to increased UV-B
exposure for several aquatic organisms. Losses of productivity in com-
mercial fisheries could result from (1) increased UV-B exposures on the
sensitive species and (2) increased UV-B exposures on organisms (e.g.,
algae) fundamental to the oceanic food chain. Hence, the first item in
Table 5--algae—is potentially significant because many commercial
fisheries depend on algae, the ultimate source of food of most oceanic
animals. Hence, a loss of algae productivity would be reflected in losses
in commercial fisheries even though these losses might be difficult to
32
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Table 5
LOSSES IN AQUATIC ORGANISMS
Species
Atgae
(diatoms)
Shrimp
(pandalus species)
Dungeness
crab
Crab
(cancer oregonensis)
Anchovy
Mackerel
Freshwater
microinvertebrates*
Excess
Mortality {%)
4
50
50
50
80
99
10
80
50
Increase in
UV-B Exposure
DNA-Weighted (%)
38
57
56
41
26
50
26
50
>50
Data
Source
Van Dyke &
Worrest, 1977
Damkaer et al.,
1978
Damkaer et al.,
1978
Damkaer et al,,
1978
Hunter et al., 1978
Hunter et al., 1978
Hunter et al.. 1978
Hunter et al.. 197R
Calkins. 1975
"Probable maximum estimate of mortality.
33
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quantify or even demonstrate outside the controlled environment of a labora-
tory. (Analysis of actual field conditions is complicated by other vari-
ables such as changes in fisheries practices and the large year-to-year
variations that occasionally characterize oceanic fisheries.)
Several commercial species tested appear to be more sensitive
than algae to increased UV-B dosages (see Table 5). Therefore, UV-B effects
would be expected to manifest themselves first in the form of shifts in the
prevalence of UV-B sensitive and UV-B resistant species in the commercial
catch. Losses in the productivity of oceanic fisheries in total due to
losses in the productivity of the algae would occur later.
b. Cancer Eye in Cattle
A causal relationship between UV-B and cancer eye has not
been proven. Hence, attempts to project increases in cancer eye would be
premature.
c. Terrestrial Plants
Direct Effects of Increased UV-B
Effects on terrestrial plants in the greenhouse and in growth
chambers are very strong, but have not been verified under field conditions.
This could reflect either the presence of effective repair mechanisms, or
some unknown interaction between plants, UV-B, and visible light at high
light intensities, or difficulties of obtaining statistically reliable data
under field conditions.
Effects considered significant may occur in the presence of
enhanced UV-B in the field, but generally this has not been proven. Labora-
tory data indicate that a 40 percent increase in UV-B might cause a 10 to 20
percent loss in the yield of many commercial species. However, the
34
-------
associated with these projections are quite large (100 percent or more).
The cognizant scientific community as a whole is unwilling to venture pro-
jections of what could happen to commercial species under field conditions,
given enhanced UV-B. They maintain that long-term (3-year minimum) field
studies, including studies of adaptability mechanisms, are needed before
making any projections.
Secondary Effects Due to Climate Changes
As described in Section III.C., UV-B enhancement may have a
direct impact on climate. However, in view of the many unknowns, reasonable
estimates for climate changes exist only for one parameter—global average
temperature.
The estimated magnitude of the global temperature change and
problems associated with estimating other agriculturally significant changes
(e.g., precipitation and regionality) are also discussed in Section III.C.
4. Future Needs
The data base for assessment of the impacts of stratospheric ozone
depletion on nonhuman biological systems is sufficiently extensive to war-
rant concern, but they are insufficient to allow definitive assessments.
Assessments of the impact on either marine or terrestrial species of
little commercial significance or on total ecosystems are even more
constrained. A series of studies with modest but sustained funding, as is
currently going on in the laboratory, needs to be continued under field con-
ditions to appraise the probability that sensitive organisms exposed to UV-B
will have the ability to tolerate the increased UV*B received (Table 6).
Analyses of light penetration, depth distributions, and avoidance
behavior are needed to reduce the large uncertainties involved in use of
35
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Table 6
NONHUMAN BIOLOGICAL RESEARCH NEEDS
Research Need
Specific Research Area
Benefit
Penetration of light in natural
waters
Depth distributions of larval
forms of marine fishes
Fisheries
Photo repair
Interactions among species
Behavioral responses
Woody plants
Hydrocarbon releases
from plants
Extend the assessments of the sensitivity of
commercially significant fish species.
Extend analyses of the interaction between
UV-B and photorepair to field experiments
to facilitate the extrapolation of existing
growth-chamber and greenhouse data to
field conditions
Replicate and expand experimental studies
of the effects of UV-B on interactions
between plants, animals, and microbial
pathogens or symbionts in both terrestrial
and aquatic experiments.
Examine the effects of UV-B on animal
behaviors particularly the ability of fishes to
avoid exposure and the pollination of crops
by bees.
Extend the analyses of the sensitivity of tree
and shrub seedlings to multiyear studies
of species of commercial significance.
Short-term
Short-term
Short-term
Short-term
Long-term
Long-term
Long-term
Short-term
36
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the data on commercially important fishes. We are relatively ignorant of
the vertical distribution, and hence exposure, of many of these species,
although several are known to spend several weeks within one meter of the
surface during early development. We lack data on their ability to
detect and avoid UV-B, and very few species have been examined relative to
wide range of sensitivity. Hence, while it is clear that though some com-
mercially important fisheries may be very severely affected, we lack suf-
ficient data to safely predict the sensitivity of species other than those
examined.
The data base for noncommercial species of land plants is also
weak and should be explored by means of multi-year studies. It is possible
that timber production may be more sensitive to increased UV-B than only as
a question of seedling survival. Although we lack data to substantiate this
hypothesis, there remains need both for further study of the action spectra
for photoeffects and for study of the mechanisms of photoactivated repair.
An understanding of the action mechanisms spectra and repair would greatly
facilitate extrapolation from greenhouse and laboratory studies to the
natural environment, and expedite extrapolation to unstudied species.
37
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C. Climate Effects
1. Background
One possible effect of ozone depletion is climate modification.
The source of such climatic modification is a change in the atmospheric
transfer of radiant energy. Ozone strongly affects this transfer in several
regions of the solar and terrestrial radiation spectra, and hence changes in
the amount and vertical distribution of ozone (as shown in Figure 4) can alter
atmospheric temperature, both near the earth's surface and throughout the ver-
tical. In turn, these temperature changes might lead to perturbations of cur-
rent weather patterns and to local changes in precipitation and temperature.
It is important to recognize that CFC's themselves, before photo-
dissociation in the stratosphere, also affect atmospheric radiation and that
these effects will combine with any radiative effects of ozone depletion. In
particular, both CFC-11 and CFC-12 absorb strongly in parts of the terrest-
rial radiation spectra. Thus, these gases reduce the escape of terrestrial
radiation from the earth (creating a so-called greenhouse effect) and tend
to warm the earth's surface. This direct radiative effect of CFC's must be
considered, along with ozone-depletion radiative effects, in making a com-
plete assessment of CFC impacts on climate.
2. Recent Research
Nearly all recent and current research on the climatic effects of
ozone depletion and of ozone-depleting substances has focused on temperature
changes. Much less work has been done on the resulting changes in circula-
tion and precipitation, although these aspects should be understood if the
full impact of climatic change is to be evaluated.
a. Mechanisms that Affect Climate Change
Over longtime scales (one year or greater), the earth-
atmosphere system maintains radiative equilibrium. Changes in atmospheric
38
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(II
a
10 —
-10
SOURCE: Log»n.
-20 -30 -40
CHANGE ON OZONE — percent
il. (1978)
-60
Figure 4. Vertical profile of ozone depletion by CFCs predicted
by a one-dimensional photochemical model.
One-dimensional photochemical models describing
tropospheric ozone depletion are more uncertain than
similar models describing stratospheric ozone, because
the tropospheric NOX levels, which critically control
production, are highly uncertain.
39
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composition (e.g., carbon dioxide increase, CFC increase, ozone depletion)
that alter the earth's radiative energy budget should be expected to cause
climate changes. It is emphasized that CFC releases are only one of many
possible causes of climate change, the dominant cause being carbon dioxide
increases due to fossil fuel combustion, and deforestation. Accurate quanti-
fication of these changes is not viable because our knowledge is inadequate.
However, some characteristics of the mechanism are known. These character-
istics are summarized below:
o Direct effects of CFC's, carbon dioxide and other greenhouse
causing gases and aerosols are expected to be monotonic but
the magnitude of their effect will generally be amplified in
polar regions.
o Ozone composition has a natural seasonal cycle and varies with
latitude. Hence changes in its composition will not necessarily
be uniform with time or altitude or over the globe.
o The response of the earth-cryosphere-ocean system to radiative
perturbations is still largely unknown and is at the core of
present research.
o The response of the system is bound to cause further anomalies
in the radiation budget that would give rise to additional
response, e.g. changes in hydrologic cycle due to circulation
changes would affect radiation budget through changes in H20
Vapor and cloud cover, (See Schneider and Dickinson, 1974).
o Changes in surface albedo from melting of ice or from UV-B
induced changes in plant growth can also produce changes in the
radiative budget.
o Additional anthropogenic changes—for example, released CQ^
in burning of fossil fuels—will cause heating of the
troposphere and cooling of the stratosphere. The latter will
in turn lead to less 03 depletion. The reduction, however, is
rather small.
o Other anthropogenic sources of greenhouse-causing gases and
aerosols may also intensify or inhibit the net radiative
effects produced by the CFC's. (See Wang, et aj_., 1976).
Climate change 1s also difficult to assess because the system
40
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may be intransitive, i.e., it may exhibit more than a single ensemble of
states (ice ages, interglacials) with no apparent changes in external
boundary conditions (solar constant atmospheric composition). (See
Schneider and Dickinson, 1974; Hartmann and Short, 1979). Multiple states
have also been obtained in solutions to photochemical models.
Thus, even though the perturbation to the radiative energy
budget might be readily characterized, the response of the climate system is
unforeseeable (e.g., radiatively, a doubling of C02 should cause a warming
of the lower troposphere, but it remains highly speculative how much warming
occurs at a particular time and place).
b. Mathematical Models
There are a number of different types of models which potenti-
ally can be used to assess climate changes. However, these models are not
developed to the point where they can adequately predict climate changes
due to CFC emissions. Research to develop and improve climate models is
the primary thrust of the National Climate Research Program under the aegis
of the National Oceanography and Atmospheric Administration.
3. Projections and Uncertainties
Temperature Changes
The development of climate models have begun to result in a
better understanding of tropospheric radiative energy budget and the re-
sponse of surface temperature to CFC induced radiative changes. The most
recent understanding of the impact of CFC releases on surface temperature
is illustrated by calculations performed by Ramanathan (Ramanathan and
41
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Dickinson, 1979) of the National Center for Atmospheric Research, It
is assumed that if the CFC emissions for CF2C12 and CFC13 continue at
their 1975 level and with steady state conditions in the atmosphere of 1
ppb for CF2C12 and 2 ppb for CFC13, then the global average surface tempera-
ture will increase by 0.4°C, This compares with an estimated 2 - 3~c in-
crease for a doubling of atmospheric concentrations of C02,
4. Future Needs
Climate research is now the responsibility of the National Climate
Program Office within NOAA. Therefore, most of the needs, listed in
Table 7, should be conducted within the framework of the National Climate
Program.
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Table 7
CLIMATE RESEARCH NEEDS
Research Need
Method
Benefits
Statistical analyses
Climate models
Trace substance monitoring
General circulation models
^rCjU;; ^z and convene workshop or. anth; j-
pogenic climate modification. Invite
national and international experts in the
field of climate modeling and monitoring.
Assess the state of the art of potential
global and regional climatic impact of
anthropogenic atmospheric perturbations,
such as ozone depletion, increasing burden
of infrared absorbing species (CFC, C02,
N20, H20), and aerosol particles.
Apply judicious statistical methods to
existing climatological data, both to
detect possible anthropogenic trends in
climate variables and ozone and to design
better monitoring systems.
Assess by means of theoretical modeling,
using an empirical data base, the climatic
changes that may occur as a consequence
of anthropogenic activity. The primary
concern will be the alteration to the radi-
ation budget by ozone removal, aerosol
formation, and introduction into the
atmosphere of other infrared absorbing/
emitting species. Include latitude
dependence and feedback by ice albedo
and clouds.
Monitor atmospheric trace substances
(including aerosols) that play a central
role in determining anthropogenic
influence on climate.
Improve general circulation models to
simulate the effects of ozone-depletion-
induced changes in tropospheric tempera-
ture, stratospheric temperature, and winds
on planetary waves and storm tracks.
Improve cloud parameterization to permit
inclusion of cloud-feedback effects.
Short-term
Long-term
Long-term
Long-term
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IV FEDERAL AND INTERNATIONAL RESEARCH COORDINATION
A. Interagency Committee on Stratospheric Ozone Protection
The Interagency Committee on Stratospheric Ozone Protection (ICSOP),
in accordance with Section 150 of the Clean Air Act Amendments of 1977, has
been functioning under the chairmanship of EPA. Membership includes:
Department of Agriculture, Department of Defense, National Institutes of
Health, Food and Drug Administration, Department of Commerce, National Bureau
of Standards, National Aeronautics and Space Administration, National Science
Foundation, Consumer Product Safety Commission, National Institute of
Environmental Health Sciences, Federal Aviation Administration, and the
National Oceanic and Atmospheric Administration.
Early in 1979 the ICSOP, in order to identify research needs and gaps,
formed three subcommittees: Atmospheric Sciences, Health Effects, and
Biological and Ecological Effects. The Atmospheric Sciences subcommittee
was chaired by the National Oceanic and Atmospheric Administration, the
Health Effects subcommittee by The Department of Health, Education and
Welfare, specifically the National Cancer Institute, and the Biological
and Ecological Effects subcommittee by the National Science Foundation.
Reports were submitted by the subcommittees in September 1979 and are
being used to guide the individual agencies involved in accordance with
their research capabilities and interests. EPA has requested the National
Academy of Sciences, in light of their expertise and recent reports on
stratospheric ozone, to evaluate the ICSOP subcommittee reports and provide
their research recommendations.
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B. United Nations Environment Program/Coordinating Committee on
the Ozone Layer
The United States is an active member of the United Nations Environ-
ment Program/Coordinating Committee on the Ozone Layer (UNEP/CCOL), which
has as its purpose the integration, evaluation, and dissemination of research
results on causes and effects of stratospheric ozone depletion. Participants
are: the nations that are major user/manufacturers of CFC's, e.g. the
United States, Canada, the United Kingdom, France, Norway, Sweden, the
Netherlands, Italy, West Germany, the USSR, Australia, and occasionally
other nations; involved international scientific organizations, e.g. World
Meteorological Organization (WMO), World Health Organization (WHO), and the
International Council of Scientific Unions (ICSU); and industry, e.g. Chemi-
cal Manufacturers Association (CMA).
The most recent annual meeting of the CCOL was held in Paris, France,
November 20 - 23, 1979. A report of that meeting will be published by UNEP
in several months. Its principal conclusions, developed by all participants,
are in excellent agreement with the recent NAS findings (discussed in
Section II) and are summarized as follows:
o The UNEP Committee on the Ozone Layer met in Paris from
20 - 23 November for its third session. The Committee
examined the substantial contributions presented to it
by various countries, and the research efforts in measuring
and modelling necessary for the study of the stratosphere.
Having considered the new information available from coun-
tries and international bodies, including comprehensive new
reports of the National Academy of Sciences of the USA and
of the Department of the Environment of the UK, its present
assessment remains broadly similar to that made by the UNEP
Committee in November 1978.
o The Committee concluded that a risk to the ozone layer is
still most likely due to chlorofluoromethane releases,
although in the future other components, such as methyl-
chloroform, which can reach the stratosphere, require
increased consideration.
45
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o Present model calculations are estimated to result in an
ultimate ozone depletion of about 15 percent, if chloro-
fluoromethane releases continue at the present rate. Ac-
cording to these models an ozone depletion of about 2 per-
cent should already have occurred. Such an amount cannot
be detected directly with present technology, and no change
attributable to human activity has been observed,
o The influence of NOX (from supersonic aircraft) and of NpO
(from fertilizers) seems to be of minor importance.
o For many species, there is an acceptable agreement within
the range of uncertainties between model calculations and
atmospheric measurements. In some cases, however, dis-
crepancies occur that cannot yet be explained.
o There is increasing, but still inadequate knowledge of
possible effects of increased UV-radiation on ecosystems
and plants, which may be the most serious impact. There
is a high degree of correlation for the relationship between
UV-B radiation and non-melanoma skin cancer in man, and
there is some indication that there may be a connection for
melanoma.
o The Committee welcomed the decision of Governments at the
International Conference on Chlorofluorocarbons in Munich
6-8 December 1978, to reduce chlorofluoromethane emissions
significantly.
o The Committee gave a number of recommendations concerning
further research and monitoring to reduce the existing
uncertainties.
o The WMO and WHO, with the support of UNEP, are continuing
internationally coordinated studies of measurements of
atmospheric constituents and health evaluation.
46
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REFERENCES
1. Briggs, R. H,, and S. V, Kossuth, 1978: "UV-B Biological and Climate
Effects Research, Terrestrial; FY77, Impact of Solar UV-B Radiation on
Crop Productivity," Final Report to USDA.
2. Caldwell, M. M., 1979: Private Communication.
3. Calkins, J., 1975: "Effects of Real and Simulated Solar UV-B in a Vari-
ety of Aquatic Microorganisms—Possible Implication for Aquatic Eco-
systems," CIAP Monograph 5, Department of Transportation, Washington,
D.C., pp. 5-33 to 5-69.
4. Cams, H. R., J. H. Graham, and S. J. Rairtz, 1979: "Effects of
UV-B Radiation on Selected Leaf Pathogenic Fungi and on Disease Sever-
ity," Final Report for Contract No. EPA-IAG-D6-0168.
5. Damkaer, D. M., G. A. Heron, D. B. Deay, and E. F. Prentice, 1978:
"Effects of UV-B Radiation on Near-Surface Zooplankton of Puget Sound,"
Technical Report, Pacific Marine Environmental Laboratory/NOAA,
Seattle, Washington 98105, FTS 399-4900.
6. Dunn, J. E., E. A. Levin, G. Linden, and L. Harzfeld, 1965: "Skin
Cancer as a Cause of Death," California Med., 102. pp. 361-363.
7. Fears, T. R., J. Scotto, and M. A. Schneiderman, 1977: "Mathematical
Models of Age and Ultraviolet Effects on the Incidence of Skin Cancer
Among Whites in the United States," Am. J.. Epidemiol., 105, pp. 420-427.
8. Green, A. E. S., 1978: "Ultraviolet Exposure and Skin Cancer Re-
sponse," Am. J.. Epidemiol.. 107, pp. 277-280.
9. Hartmann, D. L. and D. A. Short, 1979: "On the Role of Zonal Asym-
metries in Climate Change," J.. Atmos. Sci., 36, pp. 519-528.
10. Hunter, J. R., J. H. Taylor and H. G. Moser, 1978: "Effect of
Ultraviolet Irradiation on Eggs and Larvae of the Northern Anchovy,
Engraulis Mordax, and the Pacific Mackerel, Scomber Japonicus. Dur-
ing the Embryonic Stage," Photochemistry and Photobiology. Vol. 27.
11. Kaufmann, M. R., 1978: "The Effect of Ultraviolet (UVB) Radiation
on Pine Seedlings," Final Report EPA-IAG-D6-0168,
12. Kopecky, K. E., G. W. Pugh, and D. E. Hughes, 1978: "Biological Effect
of Ultraviolet Radiation on Cattle: Bovine Ocular Squamous Cell Carci-
noma," Final Report, USDA and EPA Interagency Agreement, EPA-IAG, D6-
0168.
47
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13. Lancaster, H. 0., 1956: "Some Geographical Aspects of the Mortality
from Melanoma in Europeans," Med. J_. Aust.. J_, pp. 1082-1087.
14. Lancaster, H. 0, and J. Nelson, 1957: "Sunlight as a Cause of Mela-
noma: A Clinical Survey," Med. J^. Aust., 1_, pp. 452-456.
15. Lee, J. A. H., G, R. Peterson, R. G. Stevens, and K. Vesanen,
"The Influence of Age, Year of Birth, and Date of Mortality from
Malignant Melanoma in the Populations of England & Wales, Canada,
and the White Population of the United States," Am. J_. Epidemiol.
(in press).
16. Logan, J. A., M. J. Prather, S. E. Wofsy, and M. B. McElroy, 1978:
"Atmospheric Chemistry: Response to Human Influence," Trans. Ray.
Soc.. (in press).
17. Mason, T. J. and F. W. McKay, 1974: "U. S. Cancer Mortality by
County: 1950-1969," N.I.H. Publication 74-615.
18. Moyshovitz, M. and B. Modan, 1973: "Role of Sun Exposure in the
Etiology of Malignant Melanoma Epidemiology Inference," J_. National
Cancer Institute, 5_1, pp. 777-779.
19. Ramanthan, V., and R. E. Dickinson, 1979: "The Role of Stratospheric
Ozone in the Zonal and Seasonal Radiative Energy Balance of the Earth-
Troposphere System," J_. Atmos. Sci., (in press).
20. Schneider, S. H., and R. E. Dickinson, 1974: "Climate Modeling,"
Rev. Geophys. Space Phys., J2., pp. 447-493.
21. Scott, E. L. and M. L. Straf, 1977: "Ultraviolet Radiation as a Cause
of Cancer in Origins of Human Cancer," (ed. H. H. Hiatt, e_t al_.)
Cold Springs Harbor Lab., pp. 529-546.
22. Scotto, J., A. W. Kopf, and F. Urbach, 1974: "Nonmelanoma Skin Cancer
Among Caucasians in Four Areas of the United States," Cancer, 34, p.
1333. ~
23. Scotto, J. and T. R. Fears, 1978: "Skin Cancer Epidemiology Research
Needs," National Cancer Institute Monograph 50.
24. Scotto, J., 1979: Personal Communication to Dr. H. Wiser (EPA).
25. Silverston, H. and J. H. A. Searle, 1970: "The Epidemiology of Skin
Cancer in Queensland: The Influence of Phenotype and Environment,"
British Journal of Cancer. 24, pp. 235-252.
26. Van Dyke, H. and R. C. Worrest, 1977: "Assessment of the Impact of
Increased Solar Ultraviolet Radiation upon Marine Ecosystems," NAS
9-14860, Mod. 78, NASA Lyndon B, Johnson Space Center, Houston, Texas
77058.
48
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27. Vitaliano, P. P., 1978; "The Use of Logistic Regression for Modeling
Risk Factors: with Applications to Non-melanoma Skin Cancer," Am.
Journal of Epidemiology, 108, (5), pp. 404-414.
28. Wang, W. C., Y. L. Yung, A. A. Lacis, T. Mo, and J. E. Hansen, 1976:
"Greenhouse Effects Due to Man-Made Perturbations of Trace Gases,"
Science, 194. pp. 685-690.
29. Waterhouse, J., P. Correa, C. Muir, and J. Powell, 1976: "Cancer
Incidence in Five Continents," Vol. 3, IARC Scientific Publications,
No. 15, International Agency for Research on Cancer, Lyon, France.
49
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/9-80-043
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
RESULTS OF RESEARCH RELATED TO STRATOSPHERIC OZONE
PROTECTION - Report to Congress
5. REPORT DATE
September 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO
9. P:;.~F(?~-
OPGANI_ \TICN NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
SAME AS BELOW
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Research and Development
U.S. Environmental Protection Agency
Washington, DC 20460
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This is the second EPA report to Congress on federal research required biennially
under Section 153(g) of the Clean Air Act Amendments of 1977 (Public Law 95-95). It
emphasizes the findings of EPA-supported research and related studies and presents the
latest assessment and understanding of stratospheric ozone depletion by chlorofluoro-
carbons as reported by the National Academy of Science in 1979. This EPA report does
not describe all the relevant research results obtained by other federal agencies
since Section 154 of the Clean Air Act requires them to submit separate reports, but
their results are incorporated to the extent possible. Research supported by EPA has
focused on analyzing the effects of increased UV-B exposures on humans and nonhuman
biological systems. The potential for significant adverse environmental effects has
been suggested by research accomplished to date. It has been established that
additional research, both short- and long-term, is needed to identify and quantify
the direct and indirect effects of ozone depletion in all areas—human health, other
biological/ecological systems, climate monitoring, economics, and social issues.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
58
20. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (R»v. 4-77) PREVIOUS EDITION is OBSOLETE
50
U.S. GOVERNMENT PRINTING OfFICE: 1MO -657-165/OU3
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