United States
Environmental Protection
Agency
Atmospheric Sciences Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S3-85/018 May 1985
Project Summary
Deterioration of Marble:
A Retrospective Analysis of
Tombstone Measurements in the
New York City Area
R. B. Husar, D. E. Patterson, and N. S. Baer
A data base of tombstone thickness
and depth of emblem inscription at
Veterans Administration cemeteries has
been compiled by New York University.
A subset of measurements for two
cemeteries in the vicinity of New York
City was selected for analysis in this
study. For comparable meteorological
conditions, different weathering rates
of fine grain marble tombstones were
observed for the two cemeteries. Tomb-
stones in the Cypress Hills cemetery,
which is located within an industrial
area, were observed to have higher
rates than similar stones in the semi-
rural area of the Long Island cemetery.
By using a retrospective air quality
model, which is described in another
publication, to predict SOz concentra-
tions in New York City from 1880 to
1980. concentration trends of SOz were
estimated for both cemeteries. A linear
relationship was found to exist between
the weathering rates and estimated SOz
concentrations. A value of 10 mm per
century per ppm of SOz was derived as
the best estimate for the weathering
coefficient of fine grain marble for the
New York City area.
This Project Summary was developed
by EPA's Atmospheric Sciences Re-
search Laboratory, Research Triangle
Park. NC, to announce key findings of
the research project that is fuHy docu-
mented in a separate report of the tame,
title (see Project Report ordering infor-
mation at back).
Introduction
New York University, through a pro-
gram with Task Group G, Effects on
Materials and Cultural Resources, within
the National Acid Precipitation Assess-
ment Program has compiled measure-
ments of thickness and depth of emblem
inscription of marble tombstones in over
23 U.S. Veterans Administration (VA)
cemeteries. The marble tombstones used
in these cemeteries provide a standard-
ized material, i.e., of uniform composition
and prepared under controlled conditions,
which are useful for studying stone
deterioration over the last century as a
function of geographic locations.
In this study, measurements of tomb-
stones recorded by New York University
for Cypress Hills and Long Island ceme-
teries were analyzed. Furthermore, only
tombstones prepared from Vermont mar-
ble, which is a fine grain stone, were
analyzed. The objectives of this investi-
gation were to determine weathering
rates of marble and to establish whether
a relationship existed between the weath-
ering rate and SOz concentrations that
were estimated for the cemeteries.
Discussion
In this investigation, the marble deter-
ioration rat* was obtained from the
difference between the bottom and the
top thickness measurements for the
tombstone. Weathering of most stones
was most pronounced at the top. This was
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most apparent from the rounded tomb-
stone edges and from decreasing depth of
inscriptions. The part of the stone which
was in the ground usually exhibited very
little weathering. In most cases, the
surface near the ground still had its
original smoothness.
In this analysis, considerable scatter
was observed for marble loss for each
inscription year for both cemeteries. In
fact, the standard deviation of the bottom-
top difference was comparable to the
deviation of the mean from zero, i.e., the
noise was comparable to the signal. It
was therefore necessary to select repre-
sentative years with large sample sizes
for both cemeteries before computing
mean loss in millimeters for each group.
The increase in marble loss between
successive representative years then
yielded the loss rate representative for
the intervening range of years. For the
1930 to 1955 time period, the Cypress
Hills cemetery showed a weathering rate
of about 1.5 mm per century, while the
Long Island cemetery was about half of
that rate. For the period 1955 to 1980, the
corresponding weathering rates were
about a factor of 2 lower for both ceme-
teries.
An estimate of the ambient concentra-
tions of S02for both cemeteries between
1930 and 1980 was needed in order to
derive the weathering rate of Vermont
marble in terms of S02 concentration. In
another study, ambient concentrations
were estimated using regional and local
modeling techniques for New York City,
specifically Manhattan's Central Park,
from 1880 to 1980. In order to establish
the concentration trends for the Cypress
Hills and Long Island cemeteries, it was
assumed that the concentration ratio
between Central Park and the two ceme-
teries had remained constant over the
past years. A concentration ratio was
obtained from SO2 concentration maps
drawn for the years 1969 to 1971. Based
on these maps, the S02 concentration at
Cypress Hills was about 60% ± 20% of
Central Park concentration while the Long
Island site concentration is approximately
30% ± 20% of the Central Park SO2
concentration.
Since S02 is known to promote marble
deterioration, the influence of S02 con-
centration on the weathering rate of
Vermont marble was explored. For this
part of the study, it was assumed that the
meteorological conditions for the Cypress
Hills and Long Island cemeteries did not
differ greatly for the period 1930 to 1980.
Since the cemeteries are located less
than 40 miles apart, the average meteor-
ological conditions were expected to be
similar over this time period.
A linear relationship that clearly in-
dicates increased weathering with increas-
ing S02 concentration was obtained for a
plot of the weathering rate of Vermont
marble and the corresponding S02 con-
centration. The slope of the linear rela-
tionship was 10 mm per century per ppm
of S02. This value constitutes the best
estimate of the erosion rate of Vermont
marble as a function of SO2 concentration
that could be derived from this analysis.
Conclusions
Other researchers have estimated the
weathering rate of marble from tomb-
stone measurements to range from 1 to 2
mm per century. The rates obtained in
this investigation are within this range.
Unfortunately, studies to correlate envi-
ronmental parameters, especially S02
concentrations, with weathering rates
are not reported. However, a stoichio-
metric rate relationship is reported for the
erosion in terms of S02 flux, rainfall
amount and pH, and surface wetness.
Assuming conditions that are considered
typical of the Northeastern U.S., an upper
limit of 11 mm per century per ppm S02
was obtained for the erosion of marble.
On the basis of these recent studies, the
value of 10 mm per century per ppm SO2
that was derived in this investigation
appears to be a reasonable estimate of
marble deterioration that has occurred in
the New York City area.
RudolfB. Husar and David E. Patterson are with Washington University, St. Louis,
MO 63130; N. S. Baer is with New York University, New York, NY 10021.
John W. S pence is the EPA Project Officer (see below).
The complete report, entitled "Deterioration of Marble: A Retrospective Analysis
of Tombstone Measurements in the New York City Area," (Order No. PB85-174
134/AS; Cost: $8.50, 'subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, v'A 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Atmospheric Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park. NC 27711
* U.S. GOVERNMENT PRINTING OFFICE: 1985-559-016/27045
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