What is the Effect
of Acid Rain on
Our Local Waters?
Christine Conner
Essex Agricultural and Technical
High School
Environmental Technology Field
Studies
11/22/13
TABLE OF CONTENTS
1. INTRODUCTION
(A)
WHY SHOULD WE BE CONCERNED ABOUT ACID RAIN?
(B) DOES BEDROCK LITHOLOGY AFFECT THE IMPACTS OF
ACID RAIN, PARTICULARLY IN OUR LOCAL AREA?
(C)
WHAT ARE THE CAUSES OF ACID RAIN
2. INVESTIGATION PURPOSE
A. BEDROCK LITHOLOGY OF THE AREAS
B. HOW BEDROCK LITHOLOGY AFFECTS THE LOCAL
ENVIRONMENT
C. PH AND ALKALINITY HYPOTHESIS
3. PROCEDURE
A. CREATING STATE BEDROCK LITHOLOGY MAPS AND
SAMPLING STATION GIS BEDROCK LITHOLOGY AND ACID
RAIN MONITERING SITES GIS MAP
B. LOCAL GEOLOGY OF STONE WALLS
C. HOW ROCKS ARE CHARACTERIZED ACCORDING TO THEIR
BUFFERING CAPACITY
D. LOCATION OF EACH OF THE MASSACHUSETTS ACID RAIN
MONITERING SITES
E. FIELD SAMPLING PROCEDURES
4. RESULTS
A. MAPS
B. TABLES
C. GRAPHS
5. DISCUSSION
A. COMPARISON BETWEEN CAMPUS DATA AND STATE
MONITERING DATA
B. CHANGE IN ACIDITY
C. BEDROCK EFFECT ON ACIDITY
D. OTHER FACTORS
Introduction
Acid rain consists of water droplets that are unusually acidic because of atmospheric
pollution. The most common causes of acid rain and the atmospheric pollution that causes the
acidity are sulfur and carbon dioxide. (“A Brief History of Acid Rain”) These two types of
pollution are both caused by the combustion of fossil fuels. Acidic deposition occurs in two
ways: wet and dry. Wet deposition is any form of precipitation that removes acids from the
atmosphere and deposits them on the Earth’s surface. Dry deposition polluting particles and
gases stick to the ground via dust and smoke in the absence of precipitation. This form of
deposition is dangerous however because precipitation can eventually wash pollutants into
streams, lakes, and rivers. (Grabar, 2013) Acid deposition is not present all over the globe and it
is most abundant in the northeastern United States, southeastern Canada, and most of Europe.
There are also many areas in Asia and Africa that are in danger of being impacted by acid rain in
the future. (“A Brief History of Acid Rain”)
Acid rain can be caused by many sources and some of them even occur naturally, such as
volcanoes. Although it does exist naturally, the cause can mainly be contributed to the burning of
fossil fuels. When these gases are discharged into the atmosphere they react with the water,
oxygen, and other gases already present there to form sulfuric acid, ammonium nitrate, and nitric
acid. These acids then disperse over large areas because of wind patterns and fall back to the
ground as acid rain or other forms of precipitation. Most of acid rain be can attributed to the
industrial revolution and our global issue of overpopulation. There are also many negative affects
to humans and other life. It has been proven that acid rain can cause increased chance of lung
and heart health issues. Acid rain also causes a decrease in biodiversity and reduces the chances
of survival for many species in highly affected areas.
Acidification of the environment typically occurs in sensitive areas. These areas are marked
by certain bedrock lithology which plays a major role in the deposition of acid rain. It is common
in these sensitive areas that natural rates of chemical weathering are low, so the area typically
has low ionic strength. These environments are also dominated by carbonate-low soils and
bedrock that has a high siliceous mineral composition. The carbonate-low, high siliceous
materials can be found in glaciated areas on granite, and areas with very old soils that are deeply
weathered and leached. Carbonate alkalinity is defined as the alkalinity provided by carbonate
and bicarbonate, and does not include the minor contributions to alkalinity provided by borate
(B(OH)4-), silicate (Si(OH)3O-), phosphate (H2PO4-, HPO4--, and PO4---), hydroxide (OH-and
MgOH+) and the negative contribution from protons (H+, HF, and HSO4-). In areas that have
granite present, there are not as many carbonates that are needed to balance out the acidity that is
caused by acid rain and acidic ground conditions. Granite is not composed of carbonates or
biocarbonates that would be used to buffer the ground and the surface water. The lack of
neutralization occurring builds up over time and causes lakes and ponds to become more acidic.
INVESTIGATION PURPOSE
DOES LOCAL BEDROCK LITHOLOGY AFFECT THE IMPACTS OF ACID RAIN?
Massachusetts has a very unique bedrock lithology and is very specific to each region.
For our campus, there is felsic volcanics, Avalon granite, mesozic basin sedimentary and mafic
rocks present. At the Ipswich River site there are mafic rocks, Avalon granite, and another type
of granite. At the Lake Attitash site, there is only Calcgranofels present and at Mystic Pond there
is also only calcgranofels apparent. At Thunder Bridge there are mafic rocks and granite. Finally,
at Lockwood, there are mafic rocks and metamorphic rocks.
The Mesozoic basin layer is composed of Triassic to Jurassic age sediments and basalt
flows deposited in localized rift basins. It can be intruded by Jurassic diabase and basalt dikes.
Basin sedimentary rocks cause water to have generally high sodium and sometimes high calcium
and sulfate concentrations; ground water may have moderate to high solute concentrations where
acidic or high sulfate concentrations exist and iron concentrations may be high in ground water
where Eh and pH are low. Calcgranofel surface waters have low to moderate solute
concentrations; variable potassium-to-sodium ratios; higher calcium concentrations when slightly
calcareous. Calcgranofels have a moderate sensitivity to acid deposition. Metamorphic rocks
cause moderate solute concentrations; iron concentrations may be high in ground water where Eh
and pH are low. Metamorphic rocks have a low to moderate sensitivity to acid deposition. Mafic
rocks cause high calcium- and magnesium-to-sodium ratios; variable silica concentrations
(sometimes high due to dissolution of reactive silicates); where Eh and pH are low, iron and
manganese concentrations are high. Mafic rocks have low sensitivity to acid deposition; may
have endemic flora favoring alkaline, high-magnesium and low- potassium soils and productive
aquatic faunas where calcium is high in surface waters. Felsic volcanic rocks cause generally low
solute concentrations; relatively high bicarbonate and silica concentrations; calcium and
magnesium concentrations generally are low; fluoride, uranium, and radon concentrations may
be high.
I believe that the sites that contain various types of granite will have a lower pH and a
lower alkalinity than the sites that do not have any granite present because of the lack of
neutralization effects of granite. If we examine and test various sampling sites for pH and
alkalinity than we will be able to compare the different sites and be able to identify the causes of
the chemical levels based on the type of bedrock lithology.
PROCEDURE
Through this entire lab process we had many components that needed to be completed. One
of the first things that we did was analyze the local geology of the monitoring sites for acid and
raid and for our own campus. In order to do this and create a comprehensive image, we made a
map for each area that we observed and tested. We made the maps using a computer program
called ArcMap, along with the data layers that we collected from the MassGIS website. We used
layers like topography, bedrock lithology, major roads, and political boundaries. We then labeled
the different types of rock found at each site, so that one could look at the map, and know what
the bedrock is composed of. We made maps for our campus, Upper Attitash Pond in Amesbury,
Ipswich River in Ipswich, Lockwood Pond in Boxford, Thunder Bridge in Middleton, and
Mystic Pond in Methuen.
We also analyzed the local geology before completing any field tests. Our class ventured into
the forest on our campus and collected any different kinds of rocks that we could find, and then
we brought them back to the classroom. After the rocks were back in our classroom, we
identified them. When each rock was labeled, we then researched what each kind of rock found
contained. The different elements that we found and the different minerals were recorded and
then we also analyzed the process in which that rocks were created in and the affects that glaciers
had on the type of rocks that we found on our campus.
The main types of rocks that were found were felsic volcanic, mafic, granite, metamorphic
gneiss, schist, and Cal Granofels. Felsic volcanic is a light colored, fine grained or aphanitic
extrusive or hypabyssal rock, with or without phenocrysts and composed chiefly of quartz and
feldspar, this kind of rock is igneous. Mafic rock is igneous rock that is dominated by the
silicates pyroxene, amphibole, olivine, and mica. These minerals are high in magnesium and
ferric oxides, and their presence gives mafic rock its characteristic dark color. Granite is coarse
or medium grained intrusive igneous rock that is rich in quartz and feldspar; it is the most
common plutonic rock of the Earth’s crust, forming by the cooling of magma at depth. Gneiss is
foliated metamorphic rock that has a banded appearance and is made up of granular mineral
grains. It typically contains abundant quartz or feldspar minerals. Schist is metamorphic rock
with well developed foliation. It often contains significant amounts of mica which allow the rock
to split into thin pieces. It is a rock of intermediate metamorphic grade between phyllite and
gneiss. Granofels are A medium to coarse grained metamorphic rock possessing a granoblastic
fabric and either lacking foliation or lineation entirely or exhibiting such characteristics only
indistinctly.
The type of rock that the bedrock of an area is composed of plays a major role in the acidity
of the area. Rocks that contain calcium compounds have a greater buffering capacity than rocks
that don’t, like granite. Most of the rocks found on our campus and in our area do not have a very
good buffering capacity, and cause in increase in the amount of acid rain in our area. Due to our
placement on the east coast, our region tends to have a large amount of granite bedrock. Granite
forms deep within the crust of the Earth from cooling magma.
The sites that we sampled from are located in the northeast corner of Massachusetts. All
of the sites were located in Essex County. We sampled in Danvers, Middleton, Ipswich,
Amesbury, Boxford, and Methuen. We took samples at ponds, rivers, and streams, so the type of
hydrology that was sampled from was very diverse.
The tests that were performed at each sampling site were pH, alkalinity, conductivity,
dissolved oxygen, carbon dioxide, and temperature. In order to measure pH, we used a pH meter.
To get the most accurate results, we calibrated the pH meter before we went into the field. When
we got to the sampling sites, we collected water, and then inserted the pH meter; the meter was
left in the water for about five minutes in order to get the most accurate result. Conductivity was
also measured using the pH meter, as well as temperature. The same process that was used for
pH measurement was used in the assessment of conductivity and temperature. The alkalinity test
process involved a more complex procedure that select people performed using the LaMotte test
kit. The LaMotte test kit was also used for dissolved oxygen and carbon dioxide. All of the tests
were performed at least twice, and the two results that we got were averaged in order to make the
results of our testing as exact as possible.
RESULTS
O MAPS
O DATA TABLE
O GRAPHS
6.9
43.35
67
0
987
846
4
6.2
2.5
7.8
7.5
11.5
13.25
11.5
2.75
10.9
5.7
7.2
5.6
42.856806
42.724556
42.65866
42.64658
42.61981
42.593357
42.594103
-78.980944
-71.202611
-70.89014
-70.98864
-70.98759
-70.970226
-70.966714
Longitude
Ferncroft Pond,
Danvers
6.7
53.5
0
7.2
8
11.1
Latitude
Forest Stream,
Danvers
6
37.5
0
6.2
.75/1
Carbon Dioxide Temperature ͦC
Thunder Bridge,
Ipswich River,
Middleton
6.6
50
361
5.7
Dissolved
Conductivity Oxygen
Lockwood Pond,
Boxford
6.5
55
170
ANC
Ipswich River at
Willowdale,
Ipswich
7.11
46.5
pH
Mystic Pond,
Methuen
6.3
Site
Upper Attitash
Pond, Amesbury
Table-1
pH of Sampling Site Locations
Upper Attitash Pond,
Amesbury
Mystic Pond, Methuen
Ipswich River at Willowdale,
Ipswich
Lockwood Pond, Boxford
Thunder Bridge, Ipswich River,
Middleton
Forest Stream, Danvers
Ferncroft Pond, Danvers
5
5.5
6
pH
6.5
7
7.5
Figure-
ANC of Sampling Site Locations
Upper Attitash Pond,
Amesbury
Mystic Pond, Methuen
Ipswich River at Willowdale,
Ipswich
Lockwood Pond, Boxford
Thunder Bridge, Ipswich River,
Middleton
Forest Stream, Danvers
Ferncroft Pond, Danvers
0
10
20
30
40
50
ANC
Figure-
60
70
80
Upper Attitash Pond-Amesbury
7.2
7.1
pH Value
7
6.9
pH
6.8
6.7
6.6
6.5
Date
Figure-
25
Upper Attitash Pond-Amesbury
Alkalinity
20
15
Alkalinity
10
5
0
Date
Figure-
Figure-
12/1/2001
2/1/2001
4/1/2000
6/1/1999
8/1/1998
10/1/1997
12/1/1996
2/1/1996
4/1/1995
6/1/1994
8/1/1993
10/1/1992
12/1/1991
2/1/1991
4/1/1990
6/1/1989
8/1/1988
10/1/1987
12/1/1986
2/1/1986
4/1/1985
ANC
10
5
0
4/1/2002
4/1/2001
4/1/2000
4/1/1999
4/1/1998
4/1/1997
4/1/1996
4/1/1995
4/1/1994
4/1/1993
4/1/1992
4/1/1991
4/1/1990
4/1/1989
4/1/1988
4/1/1987
4/1/1986
4/1/1985
pH
Mystic Pond
7.2
7
6.8
6.6
6.4
6.2
pH
6
5.8
5.6
Figure-
Mystic Pond
25
20
15
Alkalinity
20
4/1/2012
4/1/2010
4/1/2008
4/1/2006
6.5
4/1/2004
1/1/13
8/1/12
3/1/12
10/1/11
5/1/11
12/1/10
7/1/10
2/1/10
9/1/09
4/1/09
11/1/08
6/1/08
1/1/08
8/1/07
3/1/07
10/1/06
5/1/06
12/1/05
7/1/05
2/1/05
9/1/04
4/1/04
Figure-
ANC
15
ANC
pH
pH
Ipswich River
7.2
7.1
7
6.9
6.8
6.7
6.6
Figure-
Ipswich River
35
30
25
10
5
0
Figure-
4/1/2012
10/1/2011
4/1/2011
10/1/2010
4/1/2010
10/1/2009
4/1/2009
10/1/2008
4/1/2008
10/1/2007
4/1/2007
10/1/2006
4/1/2006
10/1/2005
4/1/2005
10/1/2004
4/1/2004
10/1/2003
ANC
4/1/2012
10/1/2011
4/1/2011
10/1/2010
4/1/2010
10/1/2009
4/1/2009
10/1/2008
4/1/2008
10/1/2007
4/1/2007
10/1/2006
4/1/2006
10/1/2005
4/1/2005
10/1/2004
4/1/2004
10/1/2003
pH
Boston Brook
7.1
7
6.9
6.8
6.7
Boston Brook pH
6.6
6.5
Figure-
Boston Brook
40
35
30
25
20
15
Boston Brook ANC
10
5
0
DISCUSSION
It seems that our streams and lakes in the area are experiencing a general decrease in
acidity over time. The change is not drastic, and the first couple of years of data collected by the
state were not that different than what we collected this past year. Many of the water bodies have
experienced great fluctuation, both up and down in the values of acidity. It seems that recently
the values have somewhat leveled out, but over the last ten years, there have been many dramatic
changes in pH, which probably negatively affects the biodiversity of our area. The area with the
most consistent pH values in Upper Attiash Pond in Amesbury. Most of the other sampling sites
were not nearly as level in their acidity as this area was. It also seems that in the last year,
according to the data that we collected, the pH value has gone down, making the areas more
acidic than they once were. Monitoring data collected by the Massachusetts Acid Rain
Monitoring Project indicate that surface water bodies have been slow to recover, showing only
slight to no improvement in acidic level, suggesting that long-term monitoring of surface waters
will be needed to assess how quickly their ecosystems are recovering with emissions from power
plants, factories and motor vehicles now significantly reduced.
The type of bedrock that was found in an area was concluded to have lined up with the
acidity and alkalinity value of the region. Areas containing bedrock that had a better buffering
capacity, tended to have a more constant acidity over time. Sites that did not have a rock type
with good buffering capacity had a higher fluctuation on acidity, as well as an overall higher
value. Alkalinity of natural water is determined by the soil and bedrock through which it passes.
The main sources for natural alkalinity are rocks which contain carbonate, bicarbonate, and
hydroxide compounds. Borates, silicates, and phosphates also may contribute to alkalinity.
Limestone is rich in carbonates, so waters flowing through limestone regions or bedrock
containing carbonates generally have high alkalinity - hence good buffering capacity.
Conversely, areas rich in granites and some conglomerates and sandstones may have low
alkalinity and therefore poor buffering capacity. The presence of calcium carbonate or other
compounds such as magnesium carbonate contribute carbonate ions to the buffering system.
Alkalinity is often related to hardness because the main source of alkalinity is usually from
carbonate rocks (limestone) which are mostly CaCO3. If CaCO3 actually accounts for most of
the alkalinity, hardness in CaCO3 is equal to alkalinity. Since hard water contains metal
carbonates (mostly CaCO3) it is high in alkalinity. Conversely, unless carbonate is associated
with sodium or potassium which don't contribute to hardness, soft water usually has low
alkalinity and little buffering capacity. So, generally, soft water is much more susceptible to
fluctuations in pH from acid rains or acid contamination.
Acid deposition can occur via natural sources like volcanoes but it is mainly caused by
the release of sulfur dioxide and nitrogen oxide during fossil fuel combustion. When these gases
are discharged into the atmosphere they react with the water, oxygen, and other gases already
present there to form sulfuric acid, ammonium nitrate, and nitric acid. The gases responsible for
acid rain are caused by the burning of fossil fuels and natural gas. In order to reduce acid rain,
there are many things we can do.
REFERENCES
"Acid Rain." Acid Rain. National Atmospheric Deposition Program, n.d. Web. 18 Nov. 2013.
<http://nadp.sws.uiuc.edu/educ/acidrain.aspx>.
"Acid Rain and Acid Deposition." Acid Rain and Acid Deposition. Texas A&M, Sept. 2012. Web. 18
Nov. 2013. <http://oceanworld.tamu.edu/resources/environment-book/acidrain.html>.
"A Brief History in Acid Rain." EPA. Environmental Protection Agency, n.d. Web. 18 Nov. 2013.
"Causes of Acid Rain." Causes of Acid Rain. Georgia State University, n.d. Web. 18 Nov. 2013.
<http://www2.gsu.edu/~mstnrhx/EnviroBio Projects/AcidRain/causes.html>.
Grabar, Henry. "50 Years After Its Discovery, Acid Rain Has Lessons for Climate Change." Mother
Jones. Foundation for National Progress, 12 Sept. 2013. Web. 18 Nov. 2013.
Krug, Edward C., and Charles R. Frink. Acid Rain on Acid Soil: A New Perspective. Tech. Science, 5
Aug. 1983. Web. 20 Nov. 2013.
<http://gen2.ca/DBHS/ScholarlyArticles/Katherine%20Leiva.pdf>.
"Office of Geographic Information (MassGIS)." Office of Geographic Information (MassGIS).
Commonwealth of Massachusetts, n.d. Web. 03 Dec. 2013. <http://www.mass.gov/anf/researchand-tech/it-serv-and-support/application-serv/office-of-geographic-information-massgis/>.
Reid, Audrey. Comparing the Responsiveness of Streams and Ponds to Decreases in Acid Deposition.
Rep. University of Vermont, n.d. Web. 20 Nov. 2013.
<http://www.uvm.edu/~streams/PDFFiles/symposium_projects/presentations/Reid_Audrey_201
0.pdf>.
Robinson, G.R., and K.E. Kapo. Generalized Lithology and Lithogeochemical Character of NearSurface Bedrock in the New England Region. Publication. USGS, 2003. Web. 20 Nov. 2013.
<http://pubs.usgs.gov/of/2003/of03-225/of03-225.pdf>.