0394C8
3
The pH scale is also logarith mic,
whic h means that a change of one
unit on the scale means a ten-fold
Bottery Acid
Lemon Juice
Vinegar
change in how acidic or alkaline a
solution is. Battery acid at pH 1 is
only one unit down the scale from
"PURE" Rain (5·6)
lemon juice (pH 2) , but is ten times
more acidic. It is 100 times more
acidic tha n vinegar, which has a pH
value of 3.
Distilled Water
tmmonia
o
,
2
,
3
,
4
ACID RAIN
,
5
l
!
7
6
!
8
NEUTRAL
ACIDIC
!
9
.'.
10
.'.
"
, '.
12 13 14
BASIC
Figure 1, The pH scale.
Acid Rain -
what it is
Unpoll uted rain is already slightly
acidic because of the presence in air of
carbon dioxide , which combines wi th
water to form carbonic acid. This rain
has a pH value of 5.6, However, rain
is seldom un polluted . When rain is
conta minated with sulphuric and nitric
acids the pH falls below 5 .6. This is
what we refer to as acid rain.
H owever, wh ile we use acid rain as
a common term to refer to this
problem, these pollutants can be
deposited on land and water in
several ways. In wet deposition, acidic
poll utants are depos ited by snow, fog
and mist, as well as rain. They may
also be deposited directly from the
atmosphere as gases or particles
withou t any association with
precipitation. This is called dry
deposition. Th us , while the term acid
rain will do for general reference to
the problem, m ore precise terms for
this form of poll ution are acidic
precipitation, or, more generally ,
acidic deposition.
In some areas wet and dry
deposition of acids are abou t eq ual. In
Newfoundland , however, there is
about six times as much wet
deposition as dry deposition.
Spring snowmelt can raise a stream's acid content to levels highly toxic to newly hatched fish.
4
Where it comes from
The acidic pollutants in acid rain
originate as emissions of sulphur
dioxide and oxides of nitrogen. Most
I
~
I
I.
of them come from three main
sources: 1) the burning of fossil fuels
(coal and oil) in thermal power plants;
2) the burning of gasoline in motor
vehicles; 3) the smelting operations of
considering the problem of acid rain ,
the concept of transportation of
pollutants to distant areas is as important as the concept of transformation from weak acid to strong
acid. Thus Newfound land - where
the total annual emissions of sulphur
dioxide is less than one month's
sulphur dioxide emissions from the
INCO nickel smelter in Sudbury,
Ontario - is concerned about acid
rain.
The major source areas of acid rain
are large industrial areas such as
Ontario in Canada , and the Ohio
River Valley area in the United States.
(lNCO's Sudbury smelter is the world's
largest single emitter of sulphur
dioxide). It is estimated that of all the
acid rain pollutants being deposited in
plants which refine nonferrous metal
ores. Power plants and industrial
sources contribute most of the sulphur
dioxide pollutants; motor vehicle
emissions are the largest single source
of oxides of nitrogen in the atmosphere.
Once into the atmosphere these
oxides of sulphur and nitrogen are
transformed by contact with sunlight,
ozone and oxygen into higher oxides,
which then combine with moisture to
form sulphuric acid and nitric acid,
two strong acids capable of doing
serious damage to the environment.
(Fig 2)
The pollutants may rapidly fall to
earth near their source area or they
may remain in the atmosphere for
Motor vehicle emissions are the largest single source of oxides of
nitrogen in the atmosphere.
days and be transported thousands of
by moving air masses. In
kilometres
OXIDES OF SULPHUR AND NITROGEN
DESPOSITIDN
wei
EMISSION SOURCES
dry
rain, snow,
mist
D
0
D
a
0
0
a
a
D
gases,
particles
lit""
--.....1I!'4
IMPACTS - aquatic
terrestrial
~
,P -
Power plants burning fossil fuels
emit sulphur dioxide.
Figure 2. The origins of acidic deposition.
0
. .-
-
,P
5
Newfoundland, approximately 60 per
cent come from Canadian sources and
40 per cent from the United States.
They are brought here by the
prevailing westerly air movements
across North America .
LABRADOR
50
100
50
100
200 1m
150
mile~
~
,
N
,.!
\..
I
.. .... ..• ..
•
• ••
•
•
.Churchi ll
..
ISO
"
How much we get
•
_. • •• • Goose);!
•• e.
• DyOY.
FoIIS*.
• • •• • •
•
• •
•
Precipitation sampler.
How much acid rain is actually
reaching us here in Newfoundland and
Labrador?
The most acidic rain in North
America falls in the northeastern
United States, where the pH averages
4.0 to 4.2 , approximately 40 times
more acidic than clean rain.
In Newfoundland , the analysis of
precipitation samples collected weekly
from eleven deSignated sites
throughout the province (Fig . 3) indicates that our most acidic
precipitation occurs along the south
coast and in the southwestern area of
, Precipitation sampling sites
• lake sampling sites
Newfoundland, measuring pH 4.5 on
average. This is about 12 times more
acidic than clean rain. The acidity
tends to decrease as you move from
the southwestern corner of the island
to the northeast. The regions around
Bonavista Bay have precipitation
which averages pH 4.8, six times
more acidic than clean rain.
NEWFOUNDLAND
50
100
50
150 km
100 miles
Precipitation in Labrador tends to be
less acidic than on the island. The
average pH value at Goose Bay is
4.8. Most of Labrador north of Goose
Bay has a precipitation pH value
higher than 4.8 , which means the rain
is less acidic.
Figure 3. Location of lake water sampling sites and 11 automatic
precipitation samplers.
I
6
Impact on fresh waters
As far as research has yet been able
to determine, the major impact of acid
rain is the acidification of surface
waters.
1.
I
~
I.
Freshwater systems -
rivers and
streams, lakes and ponds - abound
in Newfoundland and Labrador. Some
of them are more seriously affected
than others by acid rain. The ability of
a body of water to resist the impact of
acid rain is termed the buffering
capacity of the water. Some freshwater systems are very we ll buffered
Table 1. Classification scheme for the sensitivity of areas of Newfoundland and
Labrador based on regiona l geology.
Class
1
Low
2.
Low to Moderate
3.
Moderate
Extensive areas of lim estone and
dolomite
Sedimentary rocks , containing
widespread calcium and magnesium
carbonates
Volcanic terrains; major mafic igneous
complexes
4.
Moderate to High
Quartz-feldspar gneisses ; sedimentary
rocks poor in calcium and magnesium
and are completely resistant to
carbonates
acidification; others have no buffering
capacity and are extremely sensitive to
Geology
Re lative
sensitivity
5.
High
Granites and related rocks
acid rain. Generally speaking, it is the
dissolved materials in a body of fresh
water which determines its buffering
(This is a generalized and relative scale. Only in areas of class 5 and perhaps
capacity.
some areas within class 4 wo uld the sensitivity be extreme enough to cause
concern.)
Most important in buffering acid rain
are ions of calcium (Ca' + ),
magnesium (Mg' + ), carbonate (CO,'-)
and bicarbonate (HCO, -). Carbonate
but this source is not very large. The
mainly on the underlying rock . The
chemical composition of the bedrock
controls the composition of the
derived soils which , together with
glaCial tills , control the chemical make-
relative amounts of these four ions
up of surface waters.
and bicarbonate ions in surface waters
are derived partly from dissolved
carbon dioxide from the atmosphere ,
found in a body of water depends
Geological maps can be used to
identify sensitive surface waters of
Newfoundland and Labrador based on
the carbonate content of the underlying bedrock. An initial survey of
existing geological data for Newfoundland and Labrador has led to the
designation of five classes of sensitivity
to acid rain , ranging from very in-
sensitive to highly sensitive. (Table 1)
Figure 4 depicts the distribution of
these classifications throughout the
province. These preliminary maps will
be refined as more information
becomes available throug h further
research. Even at this stage of
resea rch , however, it is clear that large
areas of the province are moderately
to highly sensitive to acid rain.
Many of Newfoundland 's freshwater systems are highly susceptible to.
damage by ac id rain .
7
LABRADOR
o 59 ~ I~
o
5'0
!do
I
zqokm
i
150m
~
I
SENSITIVITY TO ACID RAIN
•
High
_
High 10 Moderate
o
Moderate
II l owto Moderate
•
Low
NEWFOUNDLAND
9 zp 4jl
6,0
8,0
o
50
milt1
ISo km
Figure 4. Areas of varying degrees of sensitivity of water to aCidification, based on regional geology.
8
Impact on fish
by acidification. They cannot survive
in waters with a pH less than 5.5.
Brook trout are the most tolerant to
increased acidity.
The effects of acid deposition on
fish are well documented for Scandinavia, southern Nova Scotia and
parts of Ontario, and the Adirondack
Table 2. pH levels at which
populations of fish species decline,
Mountains region of New York.
cease to reproduce , or disappear.
Acid rain can affect fish directly or
indirectly. One of the major direct
effects is alteration of blood chemistry.
Another is retardation of egg
development. Indirect effects include
reduction in the kinds and supply of
Species
pH Level(s)
Habitat acidification can be lethal
to fish fry.
food available to fish, and an increase
in the solubility from surrounding soils
Salmon and Trout
of certain trace metals, such as
aluminum, which are toxic to fish.
Rainbow trout
(Another metal whose solubility increases with pH -
-
increased acidity
is mercury , which, though it is not
toxic to fish, renders them inedible
from a human health point of view.)
Some species of fish are more
sensitive than others to acid in the
water. (Table 2) Among the most
Lake trout
Atlantic salmon
Arctic char
Brown trout
Brook trout
5.5
5.2
5.0
about 5
5.0
about 4.5
- 6.0
- 5 .5
- 5.5
including brook trout and Atlantic
salmon. The fry stage of trout and
-5
usually occurs in the spring as the
snow melts. Most of the acid which
Others
Lake whitefish
Northern pike
less than 4.4
4.2 - 5.2
important recreational and commercial
Atlantic salmon and Arctic char. Other
recreational species include brown
trout and rainbow trout in Newfound-
The different life stages of an individual species of fish also have
varying degrees of tolerance towards
Among trout and salmon, rainbow
increased acidity. Studies indicate that
the fry stage (shortly after emergence
from' the riverbed gravel where they
were spawned and hatched) is the
trout are the first species to be affected
most sensitive in a number of species,
land, and lake trout, lake whitefish
and northern pike in Labrador.
accumulates in the snow throughout
the winter washes into the lakes and
streams during the early runoff.
Applying the sensitivity map of
surface waters to fish distribution
species in Newfoundland and
Labrador are eastern brook trout,
salmon also coincides with the time of
maximum acidity in most rivers , which
throughout Newfoundland and
Labrador, we see that approximately
20 per cent of the province's total
Atlantic salmon production lies in high
sensitivity areas. It is also estimated
that about 20 per cent of the total
trout (brook trout and landlocked
salmon) production on the island of
Newfoundland comes from these
highly sensitive zones. Rainbow trout
and brown trout, two introduced
species, are confined mainly to the
Avalon Peninsula, whose waters are
rated moderately to highly sensitive.
The important commercial Arctic char
fishery in northern Labrador is remote
from the polluted air masses
associated with the highly industrialized areas of Canada and the
U.S.
Fish in lakes and rivers along the
southwest coast of Newfoundland
have the greatest potential to be affected by acidification . This area has
the highest rainfall in the province and
is the first area to receive air masses
moving in from the major industrial
areas of central and eastern U.S. and
Canada. Precipitation in this area has
Brook trout (left), rainbow (center) and German browns, three of many
fish species threatened by acid rain .
the lowest pH (highest acidity) in the
province.
9
Impact on soil and
plants
Less is known about the effects of
acid rain on soil and plants than on
surface waters and fish , but some
information is available.
Acid rain accelerates the leaching of
nutrients from soil; releases toxic
metals in soil; alters the chemistry of
leaf surfaces ; affects pollen ger-
White spruce pollen germination: severely retarded (left) under strong
(pH 2.6) simulated acid rain conditions, less affected by slight (pH 5.6)
acidification.
mination , fertilization and seed
development ; affects fruit formation,
seed germination and seedling growth.
Research
As acid ,rain is a low intensity factor
and terrestrial systems are complex
and variable in both space and time,
the effects of acid rain on forest
growth and soil chemistry are slow
and continuous and are not easily
demonstrated. However, the
reproductive phase of plants
(pollination , fertilization and seed
development) , seed germination and
seedling establishment are more
sensitive to acid rain , and the effects
on these are relatively easy to study
and demonstrate.
Across Canada many groups and
agencies are researching acid rain and
its effects.
Among those operating in New-
foundland and Labrador are Newfoundland's Department of the Environment, and the Environmental
Protection Service and Atmospheric
Environment Service of Environment
Canada. At eleven sampling stations
established throughout the province
(Fig. 3) these three agencies use
OBRARV
INSTITUTE OF OCEAN SCIENCES
10
automatic precipitation samplers to
make weekly collections of rain or
province; determine whether certain
pH depression (highest acid content),
areas of the island are likely to get
snow from which amounts of wet
acid rain more often than others; and
are especially important.
A survey of remote lakes in
acidic deposition are determined . This
calculate the probable frequency of
Labrador (with the exception of
program will likely be expanded during
acid rainfall events in anyone year.
northernLabrador) is also in progress
the next few years in order to make a
full assessment of the amount of acidic
precipitation taking place throughout
the province.
The Canadian Forestry Service in
Newfoundland is doing research to
develop measures of the relative
sensitivity of various types of plants to
acid rain, the effects of simulated acid
rain on forest soils, and the effects of
Canada's Department of Fisheries
and Oceans is also involved in acid
rain research. The department has
initiated a prograrl1 to document the
status of fresh waters and associated
fish populations in relation to the
impacts of acid rain in sensitive regions
of eastern Canada. This program will
establish a sound data base against
forest trees . Already there have been
which future changes resulting from
acid rain might be measured. Two
major studies have been undertaken
encouraging results. A method for
determining a buffering capacity index
by the department in the Newfoundland Region , one to determine the
for the foliage of plants has been
standardized to establish the relative
sensitivity of lakes and rivers to acid
acid rain on pollen germination in
sensitivity of plants to acid rain.
Lichens, for example, have been
found to have a very low buffering
capacity index , and therefore are
sensitive to acidic pollutants such as
oxides of sulfur and nitrogen.
Preliminary findings indicate that
pollen germination and pollen tube
growth are probably not affected at the
acidity levels of rain occurring in New-
foundland at this time. Acidity
associated with a pH value below 3.6
inhibits pollen germination and pollen
tu be growth.
Researchers in Memorial University's
geography department are attempting
to trace the origins of individual acidic
lainfall events from samples collected
at various sites in Newfoundland. The
purpose is to relate the acidity of
rainfall in these events to the sources
of pollutants and to determine the
associated weather conditions. This
will help researchers establish the
origins of acidic pollution entering this
rain and the other to document the
background levels of selected trace
metals in fish.
Water samples have been collected
from 109 small headwater lakes in
remote areas of Newfoundland. (Fig.
3) Samples of tiny aquatic plants
(p hytoplankton) and animals
(zooplankton) were taken from each
lake to determine species composition
and species dominance. Samples of
(Fig. 3). In addition , a selected
number of Atlantic salmon rivers in
Labrador will be sampled to determine
whether a more frequent sampling
program is warranted for these rivers.
Other studies planned by the
Department of Fisheries and Oceans
include a more frequent sampling of
rivers and streams in the highly
sensitive areas of Newfoundland
during the heavy fall rains and spring
snowmelt to determine times and
locations of maximum pH depressions
and associated concentrations of trace
metals in water and fish.
Finally we may note that many
lakes in Newfoundland drain bogs,
resulting in naturally acidic waters due
to the presence of organic acids. Fish
in these lakes may respond differently
from those in clear water lakes to
further acidification of the water, since
they have evolved in a naturally acidic
environment. This is also being studied
by the Department.
fish were also taken where possible.
Preliminary results from this survey
show that lakes with lowest pH values
(highest acidity levels) occur on the
southwest coast and along the eastern
side of the Great Northern Peninsula.
The second study involves
monitoring the water quality of
selected Atlantic salmon rivers on a
monthly basis. These rivers are
currently being considered as sites for
salmon enhancement activity; their
sensitivity to acid rain and their
seasonal variability in water quality, as
well as the timing of their maximum
Research includes simulated acid rain experimentation on plants, sampling water and aquatic life in headwater lakes, and monitoring salmon rivers for acid content.
11
More research needed
The study of the impact of acid rain
in Newfoundland and Labrador started
only recently , but already there is
ever growing need for energy can
place further stress on our sensitive
regions by increasing acidic deposition
in our province . Several agencies are
maintaining research and monitoring
efforts so that these threats can be met
and remedial action taken before acid
sufficient evidence to obtain an overall
rain destroys the beauty and
preliminary assessment. Although we
productivity of our province.
have areas of high sensitivity in this
province , damage does not appear to
be as serious as in other parts of
Canada such as Ontario and Nova
Scotia. However, this is not to say we
are free from any acid rain problems
- more study and research are
required. The possible impact of in-
The laboratory, center of the fight
agai nst acid rain.
creased fuel consumption to satisfy our
Glossary of terms
Acid: A concentration of hydrogen
ions (H + ) in aqueous solution.
Acidity is expressed as a pH less than
7.0 .
Base: Opposite of acid ; con-
centration of hydroxyl ions (OH-) in
Wet deposition: A process of
precipitation whereby acidic chemicals
such as· sulphuriC acid and nitric acid
are removed from the atmosphere and
deposited on the earth's surface in
rain , snow, fog , etc .
Dry deposition: The processes ,
excluding preCipitation , by which
materials are removed from the at-
solution. Basic or alkaline solutions
mosphere and deposited on the
have a pH greater than 7.0.
earth's surface. These processes in-
pH: A numerical expression of the
concentration of hydrogen ions in
aqueous solution . The units are ex-
clude deposition of both particles (such
as fly ash , sulphates and nitrates) and
gases (such as sulphur dioxide and
nitric oxide).
pressed as the negative logarithm of
the hydrogen ion concentration: pH 0
to 7 is acidic , pH 7.0 is neutral and
pH 7 to 14 is alkaline.
Acidification: The increase in
acidity of an aqueous solution due to
the addition of acids .
Transformation: The process
whereby sulphur dioxide and the
oxides of nitrogen are changed to
sulphuric acid and nitric acid in the
atmosphere. The transformation is
dependent on the interaction of these
gases with sunlight , oxygen , ozone
and particulate matter.
Buffer: A chemical which , is
aqueous solution , will resist changes in
pH or, if added to a solution, will
change the pH of that solution .
Transportation: The process
whereby gaseous and particulate
pollutants enter a moving air parcel
and are carried away from the source
area. Thus pollution can be transported great distances and spread
over large areas from a particular
pOint of origin.
12
The agencies listed below are actively involved in research and
monitoring of acid rain and have contributed to the production of this
information sheet. Further information can be obtained by writing to
these agencies.
Fisheries Research Branch
Department of Fisheries and Oceans
Newfoundland Region
P .O. Box 5667
51. John's , Newfoundland
A1X 5Xl
Atmospheric Environment Service
Environment Canada
P.O. Box 9490
51. John's, Newfoundland
AlA 2Y4
Department of Min"s and Energy
Government of Newfoundland and
Labrador
PO. Box 4750
51. John's, Newfoundland
AIC 5T7
Department of Geography
Memorial University of Newfoundland
51. John's, Newfoundland
A1C 557
Canadian Forestry Service
Environment Canada
Newfoundland Forest Research Center
P.O. Box 6028
51. John's, Newfoundland
A1C 5X8
Environmental Protection . Service
Environment Canada
P .O. Box 5037
51. John's , Newfoundland
AIC 5V3
Department of the Environment
Government of Newfoundland and
Labrador
P .O. Box 4750
51. John's, Newfoundl,nd
A1C 5T7
Published by:
Communications Division
~
l
,I
II
IB
Department of Fisheries and Oceans
Newfoundland Region
P.O. Box 5667
51. John's, Newfoundland
A1C 5Xl
(Tel: 722-4421, 4423, 4645)