0394C8 3

Bottery Acid Lemon Juice

Vinegar

The pH scale is also logarithmic, which means that a change of one unit on the scale means a ten-fold change in how acidic or alkaline a solution is. Battery acid at pH 1 is only one unit down the scale from lemon juice (pH 2) , but is ten times more acidic. It is 100 times more acidic than vinegar, which has a pH value of 3.

"PURE" Rain (5·6)

Distilled Water

tmmonia

ACID RAIN 7 8

, , , , l ! ! ! .'. .'. , ' . o 2 3 4 5 6 ACIDIC NEUTRAL

9 10 " 12 13 14 BASIC

Figure 1, The pH scale.

Acid Rain - what it is

Unpolluted 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 unpolluted . 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.

Spring snowmelt can raise a stream's acid content to levels highly tox­ic to newly hatched fish.

H owever, while 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 pollutants are deposited by snow, fog and mist, as well as rain. They may also be deposited directly from the atmosphere as gases or particles without any association with precipitation. This is called dry deposit ion. Thus , while the term acid rain will do for general reference to the problem, more precise terms for this form of pollution are acidic precipitation, or, more generally , acidic deposition.

In some areas wet and dry deposition of acids are about equal. In Newfoundland , however, there is about six times as much wet deposition as dry deposition.

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Where it comes from

The acidic pollutants in acid rain originate as emissions of sulphur dioxide and oxides of nitrogen. Most 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 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 days and be transported thousands of kilometres by moving air masses. In

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

Motor vehicle emissions are the largest single source of oxides of nitrogen in the atmosphere.

OXIDES OF SULPHUR AND NITROGEN DESPOSITIDN wei dry

D 0

D a

0 0

a 0

a D EMISSION SOURCES rain, snow,

mist gases,

particles

--.....1I!'4 lit"" IMPACTS - aquatic

terrestrial ~ ,P - -

.. - ,P

Power plants burning fossil fuels Figure 2. The origins of acidic deposition. emit sulphur dioxide.

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 .

, ,.!

\ ..

• •

• • .. .. . . . . . • • " .

• • G

• .Churchi ll

FoIIS*. . . _. • • • oose);! •• e. • DyOY.

• • •• • •

, Precipitation sampling sites • lake sampling sites

•

NEWFOUNDLAND

• • •

50 100 150 km

50 100 miles

LABRADOR 50 100 ISO 200 1m

50 100 150 mile~

~ N

I

Figure 3. Location of lake water sampling sites and 11 automatic precipitation samplers.

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Precipitation sampler.

How much we get

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 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.

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.

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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.

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 well buffered and are completely resistant to acidification; others have no buffering capacity and are extremely sensitive to acid rain. Generally speaking, it is the dissolved materials in a body of fresh water which determines its buffering capacity.

Most important in buffering acid rain are ions of calcium (Ca' + ), magnesium (Mg' + ), carbonate (CO,'-) and bicarbonate (HCO, -). Carbonate and bicarbonate ions in surface waters are derived partly from dissolved carbon dioxide from the atmosphere , but this source is not very large. The relative amounts of these four ions found in a body of water depends

Table 1. Classification scheme for the sensitivity of areas of Newfoundland and Labrador based on regional geology.

Class

1

2.

3.

4.

5.

Relative sensitivity

Low

Low to Moderate

Moderate

Moderate to High

High

Geology

Extensive areas of lim estone and dolomite

Sedimentary rocks, containing widespread calcium and magnesium carbonates Volcanic terrains; major mafic igneous complexes

Quartz-feldspar gneisses ; sedimentary rocks poor in calcium and magnesium carbonates

Granites and related rocks

(This is a generalized and relative scale. Only in areas of class 5 and perhaps some areas within class 4 would the sensitivity be extreme enough to cause concern.)

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 make­up of surface waters.

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 in­sensitive 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 through further research. Even at this stage of research , 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 .

SENSITIVITY TO ACID RAIN

• High

_ High 10 Moderate

o Moderate

II l ow to Moderate

• Low

NEWFOUNDLAND 9 zp 4jl 6,0 8,0 milt1

o 50 ISo km

LABRADOR o 59 ~ I~ zqokm

o 5'0 I !do i 150m

~ I

Figure 4. Areas of varying degrees of sensitivity of water to aCidification, based on regional geology.

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Impact on fish

The effects of acid deposition on fish are well documented for Scan­dinavia, southern Nova Scotia and parts of Ontario, and the Adirondack Mountains region of New York.

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 food available to fish, and an increase in the solubility from surrounding soils of certain trace metals, such as aluminum, which are toxic to fish. (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 important recreational and commercial species in Newfoundland and Labrador are eastern brook trout, Atlantic salmon and Arctic char. Other recreational species include brown trout and rainbow trout in Newfound­land, and lake trout, lake whitefish and northern pike in Labrador. Among trout and salmon, rainbow trout are the first species to be affected

by acidification. They cannot survive in waters with a pH less than 5.5. Brook trout are the most tolerant to increased acidity.

Table 2. pH levels at which populations of fish species decline, cease to reproduce , or disappear.

Species

Salmon and Trout Rainbow trout Lake trout Atlantic salmon Arctic char Brown trout Brook trout

Others Lake whitefish Northern pike

pH Level(s)

5.5 - 6.0 5.2 - 5 .5 5.0 - 5.5

about 5 5.0

about 4.5 - 5

less than 4.4 4.2 - 5.2

The different life stages of an in­dividual species of fish also have varying degrees of tolerance towards increased acidity. Studies indicate that the fry stage (shortly after emergence from' the riverbed gravel where they were spawned and hatched) is the most sensitive in a number of species,

Brook trout (left), rainbow (center) and German browns, three of many fish species threatened by acid rain .

Habitat acidification can be lethal to fish fry.

including brook trout and Atlantic salmon. The fry stage of trout and salmon also coincides with the time of maximum acidity in most rivers , which usually occurs in the spring as the snow melts. Most of the acid which 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 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 the lowest pH (highest acidity) in the province.

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 ger­mination , fertilization and seed development ; affects fruit formation, seed germination and seedling growth. 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.

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White spruce pollen germination: severely retarded (left) under strong (pH 2.6) simulated acid rain conditions, less affected by slight (pH 5.6) acidification.

Research

Across Canada many groups and agencies are researching acid rain and its effects.

Among those operating in New­foundland 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

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automatic precipitation samplers to make weekly collections of rain or snow from which amounts of wet acidic deposition are determined . This program will likely be expanded during 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 acid rain on pollen germination in forest trees . Already there have been encouraging results. A method for determining a buffering capacity index for the foliage of plants has been standardized to establish the relative 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 New­foundland 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

province; determine whether certain areas of the island are likely to get acid rain more often than others; and calculate the probable frequency of acid rainfall events in anyone year.

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 which future changes resulting from acid rain might be measured. Two major studies have been undertaken by the department in the Newfound­land Region , one to determine the sensitivity of lakes and rivers to acid 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 (phytoplankton) and animals (zooplankton) were taken from each lake to determine species composition and species dominance. Samples of 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

pH depression (highest acid content), are especially important.

A survey of remote lakes in Labrador (with the exception of northernLabrador) is also in progress (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.

Research includes simulated acid rain experimentation on plants, sampling water and aquatic life in head­water lakes, and monitoring salmon rivers for acid content.

More research needed

The study of the impact of acid rain in Newfoundland and Labrador started only recently , but already there is sufficient evidence to obtain an overall preliminary assessment. Although we 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 in­creased 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 ; con­centration of hydroxyl ions (OH-) in solution. Basic or alkaline solutions have a pH greater than 7.0.

pH: A numerical expression of the concentration of hydrogen ions in aqueous solution . The units are ex­pressed 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 .

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 rain destroys the beauty and productivity of our province.

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 at­mosphere and deposited on the earth's surface. These processes in­clude deposition of both particles (such as fly ash , sulphates and nitrates) and gases (such as sulphur dioxide and nitric oxide).

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.

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The laboratory, center of the fight agai nst acid rain.

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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

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

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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

Published by: Communications Division Department of Fisheries and Oceans Newfoundland Region P.O. Box 5667 51. John's, Newfoundland A1C 5Xl (Tel: 722-4421, 4423, 4645)