orvaihs
VEGETATION EFFECTS OF
COAL-FIRED POWER PLANTS
by Ibrahim Joseph Hindawi, Ph.D.
CERL-005
nvironmental
esearch
aboratory
j & \ 200 S.W. 35th STREET
ISK/ CORVALLIS, OR. 97330
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VEGETATION EFFECTS OF
COAL-FIRED POWER PLANTS
by Ibrahim Joseph Hindawi, Ph.D.
CERL-005
Con/all is Environmental Research Laboratory
200 SW 35th St.
Corvallis, Oregon 97330
To be presented at the hearing on Colstrip
in Helena, Montana, February, 1976
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VEGETATION EFFECTS OF COAL-FIRED PLANTS
Sulfur dioxide (SO^J in the atmosphere is known to create many adverse
effects upon health and welfare. It appears to be a major causal agent
affecting vegetation. Out of 23,360,000 tons of sulfur dioxide emitted
to the air over the United States in 1963, 60 percent was from coal
burning, and about two-thirds of that was emitted by power generating
plans that burn sulfur-bearing fuel. The remaining 40 percent of
the 23,360,000 tons of sulfur dioxide comes from industrial and commer-
cial buildings heated by coal or fuel oil, industrial facilities such
as petroleum refineries, and some chemical plants (1).
Sulfur dioxide causes both acute and chronic plant injury. Acute
injury is characterized by clearly marked dead tissue between the veins
or on the margins of leaves as a result of exposure to high concen-
tration of the pollutant for relatively short periods. Chronic injury
is marked by brownish-red, turgid, or bleached white areas on the blade
of the leaf.
Plants are particularly sensitive to sulfur dioxide during periods of
intense light, high relative humidity, adequate plant moisture, and
moderate temperature. They are, therefore, especially sensitive to
sulfur dioxide during the growing season in late spring and early summer.
Length of exposure and levels of toxicant affect plant sensitivity to
sulfur dioxide. Plants exposed to sulfur dioxide concentrations during
the early or late daylight hours are less affected by the gas than
plants exposed from 10:00 a.m. to 2:00 p.m. At night, when the
stomata (openings in the leaf for gas exchange with the atmosphere) of
most plants are closed, the plants are much less susceptible to sulfur
dioxide injury.
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The degree of turgidity of test plants is extremely important in sulfur
dioxide sensitivity. Soil dry enough to cause a slight wilting increases
plant resistance to sulfur dioxide injury. Turgid tomato leaves are
severely injured by sulfur dioxide, but slightly wilted leaves will be
uninjured by the same concentration of the toxicant. Young plants are
more resistant than old plants, and the middle-aged leaves are most
susceptible. These differences are probably caused by variations
in the number, size, and activity of the stomata and the quality
of the cytoplasmic contents of the cells.
Microscopic examination of leaf tissue injured by sulfur dioxide reveals
that the mesophyll cells are affected and the chloroplasts become plas-
molyzed or bleached out. The spongy tissues are often more easily affect-
ed than the palisade. Under severe conditions the epidermis cells are
also plasmolyzed. The mid-rib and large veins remain intact and green,
even though most of the leaf has collapsed.
Low concentrations of sulfur dioxide can interfere with the qrowth and
functioning of a plant without leaving visible injury. This invisible
injury may interfere with or reduce photosynthesis. Grain crops may
suffer a reduction in yield, especially if crops are damaged by sulfur
(2)
dioxide at the blossom stage. v '
(3)
Reinertv 'reported reductions in several growth parameters for Bel
tobacco variety when exposed to 0.1 ppm SO^ 8 hrs/day, 5/days/week,
for 4 weeks in greenhouse exposure chambers. Other studies (4) demon-
strated reduced roots weight of radishes without visible injury from sulfur
dioxide exposures of 40 hrs/wk for 5 wks at concentrations of 0.05 and
0.06 ppm.
Injury to agricultural crops exposed to a given concentration of sulfur
dioxide is greater than the injury to laboratory-exposed plants sub-
jected to the same concentration. This is possibly due to additional
toxicants present in the uncontrolled ambient atmosphere. Thus, injury
to agricultural crops is usually greater than can be projected from
laboratory experiments involving only one toxicant.
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It has been reported that an ordinarily harmless concentration of
sulfur dioxide (Figure 1), when combined with ozone, produced ozone-
(5)
type injury to Tobacco Bel plants. v ' No injury developed from
exposure of similar plants to identical concentrations of the individual
gases (Table 1).
Table 1. Synergistic Effect of Ozone and Sulfur
(5)
Dioxide on Tobacco Bel Plants v '
Duration, hr. Og S02 Leaf damage, %
2 0.03 0
2 0.24 0
2 0.027 + 0.24 38
4 0.031 0
4 0.26 0
4 0.28 + 0.28 75
Laboratory work has indicated that a single 4-hour exposure to nitrogen
dioxide below 2 ppm or to sulfur dioxide below 0.7 ppm did not injure
tobacco. Exposure for 4 hours to a mixture of 0.1 ppm of nitrogen
dioxide and 0.1 ppm of sulfur dioxide produced moderate injury to the
older leaves of Tobacco var Bel W^. Preliminary experiments with ozone,
nitrogen dioxide, and sulfur dioxide suggest that a mixture containing
0.05 ppm of each of these toxicants injures tobacco. ^
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Hindawi and Gordon (7 & 8) reported broad leaf injury and abnormal
growth on Scotch Pine at the Mount Storm area of West Virginia
and Maryland. The local coal-fired power plants often caused
injury to vegetation grown around the plant. In July 1972, 30 to
35 miles per hour winds of Hurricane Agnes reached the Mount Storm
area, took the plume from the 350 foot stacks of 1160 megawatt coal-
fired power plant (Figure 2) and pushed it along at ground level for
over 15 miles. This fumigated pine trees and other broad leaf plants
causing severe sulfur dioxide and acid mist injury (Figure 3 & 4).
In the Mount Storm area there are approximately one million acres
of Christmas tree plantations, cultivated by growers during the
last 25 years. During the period from 1965 to 1971, two huge
coal-fired power plants and a few small ones were built and began
steam generation within a 50 mile radius of these conifer tree
plantations. These power plants release about 788,000 tons of S0£
annually into the atmosphere along with large quantities of nitrogen
oxides, particulates, substantial quantities of fluoride and an un-
known amount of trace elements (9). During my studies and obser-
vations in 1970, 1971, 1972 (10) I found that air pollutants occurred
on farm locations 2,10 and 15 miles away from the nearest coal-
fired power plant. This 1160 megawatt electric power plant is
located at the Stoney Reservoir near Mount Storm, West Virginia
(Figure 5). Native vegetation in the area displayed symptoms of
sulfur dioxide injury such as needle tip burn (Figure 6) short
needle (Figure 7), and injury to the broad leaves (Figure 8).
The degree of growth abnormalities in Scotch Pine decreased with
increasing distance from the coal-burning power plant. Healthy
Scotch Pine that was moved to a contaminated plantation near the
power plant developed some injury (Figure 9) and diseased trees
moved to a healthy plantation showed some recovery (Figure 10).
Plants were exposed to ambient air or carbon filtered air at two
sites in the Mount Storm area. Sensitive plants were injured and
their growth suppressed only when exposed to ambient air (Figure 11).
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Branches (Scions) from Scotch Pine trees grown near the power plant
showed short needle; when grafted to healthy trees in a clean area,
the new growth was normal. When normal scions were transplanted
to unhealthy trees in a plantation where many trees suffered from
air pollutant injury, they developed short needle and tip injury
symptoms. Table 2 illustrates that hourly peak concentrations
of sulfur dioxide ranged from 0.0 to 0.36 ppm at the tree plantation
site. Concentration of .01 ppm sulfur dioxide or above occurred
20 to 29 percent of the time at the three sampling sites. The
hourly ozone and nitrogen oxide peaks at the three locations in
Mount Storm ranged from 0.0 to 0.15 ppm and 0.0 to .08, respectively.
Therefore, sufficient amounts of sulfur and nitrogen oxide were
present independently or possibly synergistically to cause the
damage that occurred in the Mount Storm plantations.
In 1975, I exposed Scotch Pine and a broad leaf plant (bush bean)
to low pH acid mist and found that short needles and classical S02
and acid mist injury developed on the leaves. The injury was typical
of that occurring on plants grown at the Mount Storm plantation.
In my opinion the injury on the broad leaves and the abnormal growth on
Scotch Pine was produced from intermittent or continuous level of
SO^, NO2, 0g and HF emitted from the coal-fired plants.
In the Cumberland Study, Hindawi (11) surveyed the effects of Toronto
power plant emissions on vegetation. The Toronto power plant is
located directly across 1/4 mile width of Ohio River from the southern
edge of New Cumberland, West Virignia. Pollutants emitting from the
stacks are primarily particulate matter, sulfur dioxide and nitrogen
dioxide. Emission of particulate matter and sulfur dioxide from the
Toronto power plant were estimated at 7,000 and 23,500 tons, respect-
ively for 1968 (12).
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Indigenous vegetation was inspected for damage by air contaminants.
Severe damage attributed to sulfur dioxide was found on Forsythia
(Figure 12, Maple (Figure 13), and Climbing Rose (Figure 14).
Classical acid mist injury also was found on beet leaf (Figure 15)
grown across the Ohio River from Toronto Power Plant. Various sensitive
plant species were placed in two separate greenhouses at The New
Cumberland Post Office. In one greenhouse all incoming gases in the
air were filtered to remove the phytotoxic gases. Unfiltered ambient
air was flowed into the other greenhouse 24 hours a day. Table III shows
growth suppression of plants grown in the ambient air as opposed to
those in charcoal filtered air.
In my opinion the injury that developed on plants grown in New Cumberland
could be attributed to sulfur dioxide and ozone individually or collect-
ively.
The combination of ozone and sulfur dioxide reduces the injury threshold
of the leaf tissue and increases the damage beyond that from the individual
pollutants. Combination of sulfur dioxide and ozone occurred frequently
at the New Cumberland Post Office during the study period. The annual
mean sulfur dioxide concentration at New Cumberland was 0.05 ppm. This
exceeds the criteria listed for average injury to vegetation (0.03) and for
adverse health effects (0.04). Dust was observed on leaves of several
plant varieties grown in Cumberland across the Ohio River from Toronto
power plant. Settle dust in combination with dew form a relatively
thick crust on the leaf surface. This crust cut off sun light, reduced
photosynthesis process, and therefore reduces formation of food production.
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A study in West Germany (13) has shown that 70 percent of the S0£ emitted
from power plant stacks is oxidized to S0^ within minutes. The trioxide
continues to form in the atmosphere,and as the combustion products mix
with atmospheric moisture sulfur acid is produced (14 & 15). This acid
may be suspended as small dropletes, which cause distinct punctuate spots
to appear on leaves. Most often, acid aerosol damage occurs during foggy
weather and the injury develops on non waxy leaves. This type of spotted
injury has been reported in Mount Storm, West Virginia, Maryland and
in Cumberland across the Ohio River from Toronto Power Plant (11).
Increased acid input upset mineral equilibrium of soil and could
cause leaching of calcium and other nutrient minerals from plant foliage,
the leaves do not develop normally, and often have a wrinkled appearance.
Increased acidification of all forms of precipitation has received the
greatest attention in the Scandinavian countries where more than 75
percent of all airborne sulfur is due to human activity. The result of
extensive pH and SO2 measurement over large land areas shown in some
cases 200 fold increase in rainfall acitvity since 1956. Rain pH as
low as 2.8 has been recorded in Sweden (16). Recent information (17)
indicated that stronger acid has been observed in rain and snow in
the Northern United States, with a single pH value as low as 2.1.
In conclusion, power plant emissions are known to adversely effect
health and welfare. These emissions appear to be a major causal agent
affecting vegetation. Low concentrations of sulfur dioxide can inter-
fere with plant growth and functioning without leaving visible injury.
This injury may interfere with or reduce photosynthesis. Grain crops
may suffer a reduced yield, especially if crops experience S0£ damaae
at the blossom stage. Injury to agricultural crops exposed to a given
concentration of sulfur dioxide is greater than the injury to lab-
oratory-exposed plants subjected to the same concentration. This is
caused by additional toxicants present in the uncontrolled ambient
atmosphere. A severe fumigation of sulfur dioxide and acid mist at
the proper time could so weaken valuable trees that it would not
survive the winter.
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Finally, as a result of the increasing construction of new power plants,
the use of high sulfur coal, and increased sulfur dioxide emissions
from the stacks, SC^ and acid mist in the United States will continue
at current or higher levels (low pH) unless improvement in SC^ controls
are achieved.
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TABLE II
SUMMARY OF HOURLY SULFUR DIOXIDE MEASUREMENTS,
MAY 28 THROUGH SEPTEMBER 28, 1970a
Concentration, ppm
per cent observations
Maximum
Average
equal to or exceeding
Station
value
value
.02 ppm
.10 ppm
Stoney River 2 miles
.36
.01
10.6
1.2
Steyer #2 10 miles
.11
.01
10.3
.1
Weise McDonald 15 miles
.10
r. - . — —
.01
9.0
.1
SUMMARY OF HOURLY NITROGEN OXIDES MEASUREMENTS
MAY 28 THROUGH SEPTEMBER 27, L970a
Concentration, ppm
Station
Maximum
value
Average
value
per cent
equal to
.02 ppm
observations
or exceeding
.05 ppm
Stoney River
2
miles
.08
.01
1.9
.4
Steyer //2
10
miles
.02
.01
1.3
.0
Weise McDonald
15
miles
.03
.01
4.8
.0
SUMMARY OF HOURLY OXIDANT MEASUREMENTS,
MAY 29 THROUGH SEPTEMBER 28, 1970a
Concentration, ppm
Station
Maximum
value
Average
value
per cent
equal to
.06 ppm
observations
or exceeding
.01 ppra
Stoney River
2
miles
.15
.06
60.8
5.7
Steyer //2
10
miles
. 13
.05
47.0
3.0
Weise McDonald
15
miles
.13
.06
46.0
3.6
aMount Storm, West Virginia—Goman, Maryland, and T.uke, Maryland —
Kaiser^ West Virginia, Air Pollution Abatement Activity. U.S. EPA,
APCO, Research Triangle Park, North Carolina. 1971. APTD-0656.
10
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FIGURE V
~
ALBRIGHT POWER PLANT
/
2 • Q
5! 5
a;
>
> i >-
cc
"» 1 §
LU I ^
DEEP CREEK LAKE
weise Mcdonald 13°.
12©
S3 OAKLAND
!)o
TASKER CORNERS GOB PILE
KINGSFORD CHARCOAL CO. E
©
17
4/i
jy
WES7ERNPORT
RESERVOIR
LUKE PULP MILL*
14,
0
I—LJ^—j-""-
fillLES
WESTERNPORT
STEYER
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Table III. GROWTH SUPPRESSION OF PLANTS GROWN IN
AMBIENT AIR AT NEW CUMBERLAND POST OFFICE
MAY 17 - JULY 8, 1966
Vegetation Growth suppression,a%
Tobacco
45
Pinto bean
25
Petunia
20
Columbine
15
Begonia
25
Cotton
10
Geranium
15
Estimated by visual comparison. A value of 25% indicates that
the growth of a plant in the ambient chamber was 25% less than
that of a similar plant grown in control chamber.
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REFERENCES
1. Rohrman, F. A. and Ludwig, J. H. Sources of sulfur dioxide
pollution. Presented at the 55th Natl. Meeting Am. Inst.
Chem. Eng., Houston, Texas, February 7-11, 1965. Session
No. 46. Paper No. 46e. pp. 1-16
2. Thomas, M. D., "Effects of Air Pollution on Plants," World Health
Organization, Monograph Series, No. 46, Columbia University Press,
New York, 1961.
3. Reinert, R. A., D. T. Tingey, W. W. Heck, and C. Wickliff. Tobacco
Growth Influenced by Low Concentration of Sulfur Dioxide and Ozone.
Agron. Abstr. 61^:34, 1969.
4. Tingey, D. T., W. W. Heck, and R. A. Reinert. Effect of Low Concen-
trations of Ozone and Sulfur Dioxide on Foliage, Growth and Yield
of Radish, J. Amer. Soc. Hort. Sci. 96:369-371, 1971.
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Synergism: Injury to Tobacco Plants, "Science, 153(3734):424-425,
July 1966.
6. Heck, W. W., "Discussion of 0. C. Taylor's Paper, "Effects of
Oxidant Air Pollutants," Occupational Med., 10:496-499, May 1968.
7. Hindawi, I. J. Examination of Indigenous Vegetation in the Vicinity
of the Virginia Electric Power Plant, West Virginia and Christmas
Trees Plantation in Maryland. Report Mt. Storm-72,1 Research
Triangle Park, N.C. July 1972.
8. Gordon, C. C. Mount Storm Study. Report to EPA under contract
No. 68-02-0229. University of Montana, Missoula, Montana. November
17, 1972.
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9. Mount Storm, West Virginia-Gorman, Maryland, and Luke, Maryland,
Kaiser, West Virginia, Air Pollution Abatement Activity, U.S. EPA,
APCO, Research Triangle Park, North Carolina. 1971. APTD-0656.
10. Hindawi, I. J., H. C. Ratsch. "Growth Abnormalities of Christmas
Trees Attributed to Sulfur Dioxide and Partiulcate Acid Aerosol,"
Presented at the APCA meeting at Denver, Colorado, June, 1974.
11. Hindawi, I. J., The Effect of Air Pollutants on Vegetation Growth
In New Cumberland, West Virginia and Knoxship, Ohio, presented at
The New Cumberland Abatement Conference, July, 1969.
12. New Cumberland, West Virginia-Knox Township, Ohio, Air Pollution
Abatement Activity, U.S. Department of Health, Education and Welfare,
Public Health Service, 1969.
13. Weber, E., Determination of the Lifetime of S0£ by Simultaneous
CO^ and S0^ Monitoring. Paper PE-25F, Second International Clean
Air Congress, Washington, D.C. 1970.
14. Thomas, M. D., and R. Hendricks, "Effect of Air Pollutants on Plants,"
in: Air Pollution Handbook, ed. P. L. Magi 11, F. R. Holden, and
C. Ackley, pp. 9.1-9.44, New York, 1956.
15. Middleton, J. T., E. F. Darly, and R. F. Brewer, "Damage to Vegeta-
tion from Polluted Atmospheres," JAPCA, 8:9-15, May 1958.
16. Oden, S. "The Acidification of Air and Precipitation and its
Consequences on the Natural Environment." Swedish Natural Science
Research Council. Stockholm. Bull. No. 1, 1968. 86 p. (typescip
trans).
17. Likens, E. G. and F. H. Bormann. 1974. Acid Rain: A Serious
Regional Environmental Problem. Science, 184:1176-1179.
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