Contamination of Rivers and Lakes from Mercury in the US
1
CHAPTER I
Introduction
In the United States (U.S.), many cases of mercury contamination and even deaths have
been reported and documented. One of the more famous cases of such contamination is the case
of American film director and actor, Jeremy Piven. Piven, known for his roles in ‘Runaway Jury’,
‘The Family Many’ and ‘Rush Hour 2’ was diagnosed in 2008 with Hydrargaria, a disease caused
by exposure to mercury or its compounds (Wikimedia Foundation Inc., 2010). Piven’s disease
which brought symptoms of fatigue1, neuro-muscular dysfunction2 and dizziness, was attributed to
his habitual consumption of sushi for over twenty years. In order to remove the large amounts of
mercury within his system, doctors used chelation therapy3 (Marikar & Ferran, 2008). In his
exclusive interview with Diane Sawyer on ‘Good Morning America’ Piven stated, “I thought was
doing the right thing”; however, an article written by ‘Theimproper’ in July 2010 states, “As it turns
out, a January 2008 investigation by The New York Times found so much mercury in tuna sushi
from 20 Manhattan stores and restaurants that a regular diet of six pieces a week would exceed
the levels considered acceptable by the Environmental Protection Agency4.” Mercury, although can
be expelled from the body, heavy or prolonged exposure can pose a serious health threat
especially in fetuses, infants and young children (Wikimedia Foundations Inc., 2010).
Fatigue – Physical or mental exhaustion, weariness (Webster’s New World College Dictionary, 1996)
Neuro-Muscular Dysfunction – Dysfunction of or involving both nerves and muscles (Webster’s New
World College Dictionary, 1996)
3
Chelation Therapy - The administration of chelating agents to remove heavy metals from the body
(Wikimedia Foundation Inc., 2010)
4
Environmental Protection Agency - An agency of the federal government of the United States charged
with protecting human health and the environment, by writing and enforcing regulations based on laws
passed by Congress (Wikimedia Foundation Inc., 2010)
1
2
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The Element of Mercury
Mercury, a naturally occurring metal in the Earth’s crust (Katz & Heuss, 2006) is a silverwhite metallic chemical element, liquid at ordinary temperatures, which sometimes occurs in a free
state but usually in combination with sulfur (Webster’s New World College Dictionary, 1996).
Mercury, represented by the symbol ‘Hg’ which comes from the Greek word hydrargyrum meaning
“liquid silver”, has the period number six (6), group number twelve (12), atomic weight 5 two
hundred point five nine (200.59) and atomic number eighty (80) on the periodic table (Appendix I).
It has a melting point and boiling point of two hundred and thirty four point three two Kelvin (234.32
K (-38.83°C or -37.89°F)) and six hundred and twenty nine point eight eight Kelvin (629.88 K
(356.73°C or 674.11°F)) respectively (Jefferson, 2010).
The element is also known to be a pollutant which can enter aquatic ecosystems and
become highly toxic to living organisms. Upon entering, it can lower reproductive success, hamper
the growth and developmental process and even cause death of various species. Organisms such
as larvae, eggs, filters feeders (eg. clams), large organisms (eg. tuna) and all other life forms living
to the surface and bottom where pollutants may settle are mostly affected by mercury pollution
whether indirectly or adversely (U.S. Environment Protection Agency, 2010).
There are several forms in which mercury can exist. They include elemental, organic and
as ionic salts.

Elemental Mercury – Mercury in this form, Hg(0), exists as a liquid at room temperature but
because of its high volatility6 it can easily be converted in to a gaseous form.

Organic Mercury – This form of mercury can combine with organic groups to form organic
mercury. One of the most common compounds is methyl mercury and is known to be
Atomic Weight – The weight of one atom of an element expressed in atoms mass units; it is the average
weight of all the isotopes of the element (Webster’s New World College Dictionary, 1996).
6
High Volatility – Quick to vaporize or evaporate (Webster’s New World College Dictionary, 1996)
5
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highly toxic, bioavailable7 and soluble in water (Meagher et al.). This compound was also
responsible for the death of ‘world-class chemist’ Karen Wetterhahn, a college professor at
Dartmouth College in New Hampshire, United States (U.S.). Wetterhahn’s precautionary
measures were insufficient when two drops of the highly toxic compound spilt on her
gloves on August 14th, 1996. Wetterhahn, after being exposed, succumbed to her illness
on June 8th, 1997 (Endicott, 1998).

Ionic Mercury Salts – In this form, mercury can combine with other chemicals (i.e. chlorine)
to form salts and assume a +1 or +2 valence8 state. Although these compounds are not
readily soluble in water and are less toxic than organomercury compounds, they are
hydrophobic9 and collect in tissue with high lipid content (Meagher et al.).
Although mercury exists in these forms, mercury undergoes a wide range of chemical and physical
changes as it cycles through the environment and can be found in traces in coal and other
geological materials (Katz & Huess, 2006). Discussion of the causes and effects of mercury on
human health and the aquatic environment will be done later on in this document.
The Importance of Rivers and Lakes in the United States
Approximately seventy five percent (75%) of the world’s surface is covered by water but
only a small percentage is fresh and accessible. Once precipitation occurs, water may directly be
deposited into rivers and lakes or may be intercepted by vegetation or become part of surface
runoff which ultimately makes its way to rivers and lakes and finally the oceans (Smol, 2002).
Bioavailable – The rate at which a drug, trace element, etc. enters the bloodstream and is circulated to
specific organs and tissues (Webster’s New World College Dictionary, 1996)
8
Valence – The capacity of an element or radical to combine with another to form molecules, as measured
by the number of hydrogen or chlorine atoms which one radical or one atom of the element will combine
with or replace (Webster’s New World College Dictionary, 1996)
9
Hydrophobic – Not capable of uniting with or absorbing water (Webster’s New World College
Dictionary, 1996)
7
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A lake is a body of either fresh or salt water that is located inland, is not part of an ocean
but is usually larger than a pond. There are many types of lakes such as glacial10, oxbow11,
artificial12, underground13 etc. but natural lakes are usually found in mountainous areas. Most lakes
have at least one natural outflow in the form of a river or stream, which maintain a lake's average
level by allowing the drainage of excess water. One of the areas within the U.S. that is notorious for
its many lakes is Minnesota and is commonly called ‘the land of ten thousand lakes’ (Wikimedia
Foundation Inc., 2010). There are also several other great lakes located in North America such as
the Ontario, Erie and Michigan lakes (United Nations Environment Programme, 2010).
Rivers are natural flowing body of water usually freshwater flowing downhill towards an
ocean, a lake, a sea or another river. Rivers that are small are referred to as streams, rivulets,
brooks, rills and tributaries. In the U.S., there are many rivers. Some of the more renowned ones
include the Mississippi River, which is the largest river system in North America. It is approximately
two thousand three hundred and twenty miles (2320 miles) long. Other well-known rivers in the
U.S. comprise of the Ohio River, largest tributary by volume of the Mississippi River which is
approximately nine hundred and eighty one miles (981 miles), Missouri River, Yellow Stone River
which is a tributary of the Missouri River and the Colorado River (Wikimedia Foundation Inc, 2010).
Freshwater creates a hypotonic14 environment for aquatic organisms and is an important
natural resource for the survival of all ecosystems (Wikimedia Foundation Inc., 2010) and
10
Glacial lake - a lake with origins in a melted glacier, like a kettle lake (Wikimedia Foundation Inc.,
2010)
11
Oxbow lake - A lake which is formed when a wide meander from a stream or a river is cut off to form a
lake. They are called "oxbow" lakes due to the distinctive curved shape that results from this process
(Wikimedia Foundation Inc., 2010)
12
Artificial lake - A lake created by flooding land behind a dam, called an impoundment or reservoir, by
deliberate human excavation, or by the flooding of an excavation incident to a mineral-extraction
operation such as an open pit mine or quarry (Wikimedia Foundation Inc., 2010)
13
Underground lake - A lake which is formed under the surface of the Earth's crust. Such a lake may be
associated with caves, aquifers or springs (Wikimedia Foundation Inc., 2010)
14
Hypotonic – Having an osmotic pressure lower than that of an isotonic 14a solution (Webster’s New World
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Contamination of Rivers and Lakes from Mercury in the US
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requirement for the economic development of any region (United Nations Environment
Programme, 2010). In the past as well as today, rivers and lakes have served a very important part
of the natural ecosystem. Rivers have been used not only as a source of water but for obtaining
food such as fish and other aquatic life, transport, as a defense measure, source of hydropower to
drive machinery, bathing and unfortunately as a means of disposing waste. Lakes such as the
Great Lakes in North America on the other hand, besides holding approximately twenty percent
(20%) of the worlds surface freshwater, provides a foundation for the international maritime
commerce15 and supports the recreational and commercial fishing industry (Petering & Klump,
2003).
Mercury as a Problem
A pollutant, as is defined by the Webster’s New World College Dictionary (1996), is
something that pollutes; especially a harmful chemical or waste material discharged into the water
or atmosphere. Lakes and rivers are usually seated downhill from all human influences and are
therefore subjected to different types of pollutants which may originate from different sources.
These sources may include stationary, mobile and/or indoor sources, most of which are humanmade sources (U.S. Environment Protection Agency, 2009). With that in mind and understanding
that the presence of mercury in the aquatic environment can pose serious threats to the species
living within, it is practical to state that there is a danger in emitting mercury into the rivers and
lakes in America. There are three major objectives of this study. They include:
College Dictionary, 1996)
Isotonic – Having equal tension; same osmotic pressure (Webster’s New World College Dictionary,
1996)
15
International Maritime Commerce - is a non-profit making organisation, established in 1981 to act as a
focal point in the fight against all types of maritime crime and malpractice (Commercial Crime Services,
2010).
14a
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
To understand the causes and effects of mercury in rivers and lakes;

To discover technological devices, equipment and advancements which prove helpful in
lowering or removing the amounts of mercury within rivers and lakes; and

To thoroughly review the methods that play a role in obtaining measurements along with
the advantages and disadvantages of their use.
In order to comprehend why this document is of great significance, this researcher must make
aware the importance of testing mercury and the benefits of completing this manuscript.
Importance of testing for mercury
Mercury is a very important testing compound as it as well as its components have high toxicity
levels and are therefore known to be hazardous elements (U.S. Geological Survey, 2009). For this
very first reason is why the second and third reasons are also important. With this in mind, testing
mercury is also important because mercury’s toxicity can pose a serious threat to the aquatic
environment and finally it can also be harmful to humans.
Benefits of this Research Document
It is hoped that this research paper will highlight important factors which will benefit
readers as well as this researcher. Overall, it is mostly expected that environmentalists will be
updated on the advantages and disadvantages of methods and devices uses and can proceed to
entertain the idea of developing new devices or strategies for test mercury in rivers and lakes in
this country.
For this study, it is the intension of this researcher to answer three basic questions within
this document. They are:
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1. What are the sources of mercury on the aquatic environment such as rivers and lakes?
2. What are the methods and devices used to test for mercury in these types of water
bodies?
3. What are the advantages and disadvantages of using these types of methods and
devices?
In order to proceed with the solutions to these questions, understanding the history of mercury is
very essential.
_______________________________
CHAPTER II
Background
The History of Mercury
Mercury is metal as well as a persistent organic pollutant (POP)16 and is considered to be
a virulent poison. It was found in thirty five hundred year old Egyptian tombs but is usually found
free in nature and is primarily obtained from the mineral cinnabar (HgS) (Radiochemistry Society,
2003). Mercury is a poor conductor of heat, as compared with other metals, and a fair conductor of
electricity. It easily forms alloys with many metals, such as gold, silver, and tin. The most important
salts of mercury are mercury chloride which is a violent poison, mercurous chloride (calomel,
occasionally still used in medicine), mercury fulminate, a detonator widely used in explosives, and
mercuric sulfide, a high-grade paint pigment. Mercury can be readily absorbed through the
respiratory tract, the gastrointestinal tract, or through unbroken skin when contact is made
(Radiochemistry Society, 2003).
16
Persistent Organic Pollutant - are organic compounds that are resistant to environmental degradation
through chemical, biological, and photolytic processes (Wikimedia Foundation Inc., 2010).
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Mercury comes from sources that are both natural and anthropogenic. Natural sources
include local geological deposits, volcanic eruptions and volatilization from the oceans whereas
anthropogenic sources, on the other hand, include alkali and metal-processing industries,
incineration of medical and other waste, the pulp and paper industry and the mining of gold and
mercury (Smol, 2002). In the U.S., mercury compounds are manufactured in small amounts for
specialty uses, such as chemical and pharmaceutical applications. Larger quantities of these
compounds are generated as byproducts from pollution control activities at gold mines or in waste
(Environmental Protection Agency, 2010). Once mercury is released into the atmosphere, there are
many causes for concern as it is a dangerous pollutant and tend to be highly persistent. In the
atmosphere, mercury is transported and deposited on the earth's surface by rain and snowstorms,
as well as wind storms and forest fires. The transport and deposition of mercury is dependent upon
many variables such as meteorological conditions, other chemical pollutants emitted along with
mercury, and the chemical make-up of the air mass (New Hampshire Department of Environmental
Services, 2003).
Although mercury is said to be a very dangerous metal in certain forms, the metal is widely
used in many areas for a variety of purposes. It is used in laboratory work to make instruments
such as thermometers, barometers and diffusion pumps. It is also used in making mercury-vapor
lamps and advertising signs and is used in mercury switches and other electronic apparatus. In
addition to the uses listed, mercury is used in making pesticides, mercury cells for caustic soda and
chlorine production, dental preparations, anti-fouling paint, batteries, and catalysts (Radiochemistry
Society, 2003). Also, through self-injection, mercury (elemental) has been used by those who are
suicidal or who seek to improve sexual or athletic performance (Davey & Benson, 1999).
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Documented Mercury levels in the US
In the U.S. there have been several studies conducted to determine the levels of mercury
in rivers, lakes, streams and other aquatic ecosystems. A scientific investigation report was
documented under the United States Geological Survey17 which conveyed information about
mercury in fish, bed sediment and water from streams across the U.S. over a seven year period,
beginning 1998 to 2005. In the report, several facts were highlighted. The primary objective of the
report was to describe the occurrence and distribution of total mercury in fish tissue in streams in
relation to regional and national gradients of mercury source strength and other factors that were
thought to affect mercury bioaccumulation, including wetland and other land-use and land-cover
types. The source strength included atmospheric deposition, gold and mercury mining along with
urbanization. There were also other objectives within the report which included to evaluate total
mercury and methyl mercury in streambed (bed) sediment and stream water in relation to these
gradients and to identify ecosystem characteristics that favor the production and bioaccumulation
of methyl mercury.
Data within the report were aggregated from six (6) studies which covered a total of three
hundred and sixty seven (367) sites across the United States (Appendix II). Areas sampled were
major hydrologic basins which encompass forty five percent (45%) of the land area of the
conterminous U.S. The assessment of spatial distribution was done using maps and exceedance
frequency distributions. The majority of the sites were on the eastern half of the U.S. and most of
the sites mined basins were in the western half of the U.S. (Appendix III and IV).
17
United States Geological Survey - is a science organization that provides impartial information on the
health of our ecosystems and environment, the natural hazards that threaten us, the natural resources we
rely on, the impacts of climate and land-use change, and the core science systems that help us provide
timely, relevant, and useable information.
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Data collected from the field came from different areas. Fish, (included species such as
Bowfins, Catfishes, Pikes and Trout) collected were primarily done via electro-fishing but also
collected by rod/reel and gill nets. Fish were collected from two hundred and ninety one sites.
Stream-water samples were collected by dipping Teflon bottles in the centroid streamflow by use if
trace-metal techniques. In the laboratory (five different laboratories used), analysis of fish samples
only included total mercury because ninety five percent (95%) of more of the mercury in most fish
fillet/muscle tissue is methyl mercury.
This report had numerous important conclusive results and conclusions for mercury across
the U.S. some of which are highlighted below.

Fish in streams receiving higher amounts of mercury due to atmospheric load,
gold or mercury mining, or urban contamination were found gerally to have higher
concentrations of mercury;

The strongest correlations with environmental characteristics were found for
largemouth bass, a top-predator/piscivorous fish, but significant correlations were
also found for brown and rainbow-cutthroat trout, with selected environmental
characteristics that were often different from those found for bass or other sunfish;

If sites in gold or mercury mined basins were excluded from statistical analysis, the
most
important
environmental
characteristics
for
predicting
increasing
concentrations of unfiltered methyl mercury in streams were higher concentrations
of dissolved organic carbon, unfiltered total mercury and bed-sediment methyl
mercury as well as higher basin percentages of wetland and lower pH.
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
11
Mercury concentrations in fish at more than two thirds of the sites exceeded the
value of 0.1 µg/g mercury wet weight that is of concern for the protection of fish
eating mammals, including mink and otters;

The highest concentrations among all sampled sites occurred in fish from
blackwater coastal-plain streams draining forested land or wetland in eastern and
southeastern United States, as well as from streams draining gold- or mercurymined basins in the western United States;

Across the U.S., concentrations of methyl mercury in unfiltered water and in bed
sediment were generally low

Across all sites, fish mercury was not significantly different between sites in unmined basins compared to mined basins, except for smallmouth bass.
Overall, it was noted that mercury increases with age and size in top-predator fish and can
therefore be lower in whole body fish compared to muscle or fillet. In this study, it is evident that
gold and mercury mining played an important role in higher fish to mercury concentrations at
selected sites and can therefore be concluded that these two metal result in significant levels of
mercury in the aquatic ecosystems.
____________________________
CHAPTER III
Mercury in Rivers and Lakes
Chemistry
In the chemistry of mercury within the environment there are three oxidation states: 0, 1+
(mercurous), and 2+ (mercuric). Although it forms few simple compounds, it forms several simple,
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water-soluble mercuric compounds: mercuric chloride, HgCl 2 ; mercuric nitrate, Hg(NO 3 ) 2 ; and
mercuric acetate, Hg(CH
3
COO)
2
. The mercurous chloride, Hg
2
Cl
2
, is insoluble in water.
Relatively stable organometallic compounds are formed with aliphatic and organic compounds. Of
all the mercury compounds formed methylmercury (CH 3 –Hg + ) is the major polluting form. Within
enzymatic
reactions,
methylmercury
reacts
with
thiol
groups.
(Magos,
1987).
Cycling
As stated previously, mercury can enter the environment through natural or anthropogenic
sources. When mercury exists as elemental mercury within the atmosphere, it can be cycled within
the environment for a year where it can become widespread. During the one year period, the
elemental mercury which is in the form of a vapor can undergo a photochemical oxidation where it
is turned into organic mercury. If it combines with water vapors, it can travel back to the surface of
the Earth as rain but this type of water will be deposited on soils and different bodies of water. In
soils, the mercury will accumulate until it is released again; however, in water bodies the inorganic
mercury can be converted into mercury sulfide which can settle in the water and sediment or be
converted through sulfate processing bacteria into methylmercury.
At this point, a food chain reaction occurs where the new created methylmercury can be
consumed by the next higher organism in the food chain or can stick to plankton where it
eventually will be consumed. As the process continues where different predators prey on the
smaller subject, eventually the methylmercury becomes consumed by humans or other animals. As
alternative process can also occur where elemental mercury and even methylmercury can vaporize
and re-enter the atmosphere and once again cycle through the environment. This entire process is
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further simplified in Appendix V (Brian et al., 2002; Irwin, 2002; Oosthuizen et al., 2001 & Shannon,
2001).
______________________________
CHAPTER IV
Effects of Mercury
Based on the information given so far within this document, it is apparent that this
compound known as mercury and all its constituents seem to be quite harmful. In chapter two it
was noted that mercury comes from sources that are both natural and anthropogenic and that in
the U.S. the larger quantities of mercury compounds can be detected through the byproducts of
activities from gold mines or wastes. Understanding the sources of mercury and its compounds are
very essential to the further understanding of health effects of mercury on humans and aquatic life
which is discussed in this section.
Health of Humans
The EPA estimates that about 51 tons of mercury are emitted each year from coal-burning
power plants, lesser amounts coming from oil- and gas-burning units. The EPA estimates that
emissions from coal-fired utilities account for thirteen to twenty six percent of the total (natural plus
anthropogenic) airborne emissions of mercury in the U.S. The EPA therefore concludes that "utility
mercury emissions are of sufficient potential concern for public health to merit further research and
monitoring" (Finkelman & Tewalt, 1998). Most often, mercury entering our bodies is in the form of a
vapor or is readily absorbed through in the ingestion contaminated fish and drinking water. Once
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mercury gets into the body its main target areas are the brain and kidneys and in to the fetus
through the placenta of pregnant women. However, mercury can be excreted out of the body
through urine, feces, expired air and breast milk.
Although mercury can be excreted through various processes, the reason why mercury is
so toxic is because mercury has the ability to bins to molecules that contain sulfur and other
chemical binding sites in the cells. With high toxicity in the body, exposure to mercury can cause
various diseases and symptoms that can mimic other ailments. Some of these conditions include
erethism or “mad hatter syndrome” which is caused by nervous system toxicity. This disease
includes symptoms of shyness, insomnia, mood swings and memory problems. Other symptoms
may include Parkinsonian symptoms, tremors, loss of balance, impaired sexual function and
slurred speech or dysarthria. Toxicity within the kidneys can lead to renal failure while skin toxicity
causes allergic dermatitis, chelitis (cracked corners of the mouth), gingivitis, excessive salivation
and stomatis (sores in the mucous membranes of the mouth). Symptoms within the gastrointestinal
tract can include nausea, vomiting, diarrhea, and colitis. Chronic diseases such as neurologic
disease, ADHD, autism, heart disease, autoimmune diseases can also be caused or worsened by
mercury (Hyman, 2009).
Aquatic Environment
Once mercury has entered the aquatic region it can have several effects. With each trophic
level, mercury can become increasingly toxic as it is accumulated by fish, invertebrates, mammals
and aquatic plants. Of all the mercury compounds that can be highly toxic within the aquatic
environment, methylmercury seem to accumulate the fastest and can biomagnify in higher trophic
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species, localizing mostly in the muscle tissues. Although sediment is usually the primary source of
mercury in most aquatic systems, the food web is the main pathway for accumulation.
As the mercury compound accumulates, toxicity can be influenced by the form of mercury,
the environmental media, environmental conditions, the sensitivity or tolerance of the organism,
and the life history stage. Toxicological effects only occur because mercury binds to proteins and
alters protein production or synthesis. These effects can cause reproductive impairment, growth
inhibition, developmental abnormalities, and altered behavioral responses. Exposure to low
concentrations of mercury may not result in mortality directly, but may retard growth thereby
increasing the risk of predation (National Oceanic and Atmospheric Administration, 2005).
____________________________________
CHAPTER V
Methods and Devices for Testing Total Mercury
Testing for mercury in rivers and lakes may require the use of various methods and
devices controlled only by professional scientists (following the quality assurance and quality
control guidelines) who are equipped with the necessary gears to protect themselves from
contamination. As such, there are a variety of methods that have been used in the past and are still
practiced today. As a complement to these methods, devices or instruments used may also require
proper handling.
There are numerous methods which have been approved by the EPA and are currently
used by the environmental community to test for mercury in water samples (Table 1). For this
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research however, three of these methods will be focused on to avoid repetition since most
methods share the same types of instruments to carry out various analytical studies.
Method One
According to the Environmental Protection Agency, Method 200.8 is a method used to test
for metals in water using the Inductively Coupled Plasma/Mass Spectrometry (ICP-MS) instrument.
The instrument, ICP-MS (Appendix VI), plays a significant role when using this method to test for
mercury. The instrument is highly sensitive and capable of deterring a range of metals including
mercury along with several non-metals at concentrations below one part in 1012 (part per trillion). It
is based on coupling together an inductively coupled plasma as a method of producing ions
(ionization) with a mass spectrometer as a method of separating and detecting the ions. ICP-MS is
also capable of monitoring isotopic speciation for the ions of choice. The ICP-MS allows
determination of elements with atomic mass ranges 7 to 250 (Wikimedia Foundation Inc., 2010).
Due to the fact that rivers and lakes fall in the category known as “surface waters”, the
EPA approved method would seemingly be used to determine a variety of trace elements (Table 2)
in this and other types of water and wastes using the above instrument. For this method, sample
solutions are pneumatically nebulized into radio-frequency plasma where ionization occurs. The
ions are extracted from the plasma through a differentially pumped vacuum interface and
separated on the basis of their mass-to-charge ratio by a quadruple mass spectrometer. Separated
ions are detected by an electron multiplier or Faraday detector18 and the ion information processed
by a data handling system. Isobaric and polyatomic interferences relating to the technique must be
recognized and corrected (Columbia Analytical Services, Inc., 2010). The instrument is capable of
18
A Faraday detector consists of a metal cup that is placed in the path of the particle beam. The aerosol has
to pass the filter inside the cup. The filter has to be isolated. It is connected to the electrometer circuit
which measures the current (Wikimedia Foundation Inc., 2010).
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scanning the mass range 5-250 amu with a minimum resolution capability of 1 amu peak width at
5% peak height (Environmental Monitoring Systems Laboratory, n.d).
Once samples have been analyzed, calculations may follow. Sample data should be
reported in units of μg/L for aqueous samples or mg/kg dry weight for solid samples (this may be
used for analysis of sediment samples). It is important not to report element concentrations below
the determined MDL. For total recoverable analytes in solid samples, round the solution analyte
concentrations (μg/L in the analysis solution) then multiply the μ/L concentrations in the analysis
solution by the factor 0.005 to calculate the mg/L analyte concentration in the 100 mL extract
solution. Calculate the concentration using the equation below:
Sample Concentration (mg/kg) = C x V
Dry-weight basis
W
where:
C = Concentration in the extract (mg/L)
V = Volume of extract (L, 100 mL = 0.1L)
W = Weight of sample aliquot extracted (g x 0.001 = kg)
If additional dilutions were made to any samples, the appropriate factor should be applied to
calculate analyte concentrations in the extract solution (Environmental Monitoring Laboratory
Systems, n.d.).
Although this method is successful in analyzing total mercury in waters, in the past there
was a huge disadvantage. As stated before, there are interferences which can occur during
analysis and had to be corrected. Table 3 outlines some of the common molecular background
interference in the ICP-MS. In order to avoid this, the method needed to be updated. Although the
use of Collision Reaction Cell (CRC) technology is generally considered the most reliable method
for removing polyatomic interferences in ICP-MS, unfortunately the EPA Office of Water prohibited
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18
the use of CRC ICP-MS for Drinking Water Compliance Monitoring (considered when removing
water from rivers or lakes and used from consumption purposes). Therefore, performance of this
method had to be completed without CRC which allowed polyatomic interferences to occur (Agilent
Technologies, n.d.).
On March 12, 2007, this disadvantage was overcome when the EPA considered their
experience with Clean Water Act (CWA) methods and problems with matrix interferences, and
information that used a collision cell improved the accuracy of analyses in some wastewater
samples. Thus, use of collision cells with EPA Method 200.8 for CWA purposes fell within the
scope of the explicit flexibility (Environmental Protection Agency, 2010).
Other interferences which are notably important when considering the use of this method
and device include:
1. Isobaric elemental interferences caused by isotopes of different elements which form
singly or doubly charged ions of the same nominal mass-to-charge ratio and cannot be
resolved by the mass spectrometer in use.
2. Signals from relatively abundant isotopes can coalesce at the wings of relatively less
abundant isotopes leading to loss of resolution and poorer quantitation.
3. Physical interferences that hinder transport of the sample into the plasma (e.g., viscosity
effects, high levels of solids.
4. Memory interferences (carry-over) of isotopes from previous sample runs (Columbia
Analytical Services, Inc., 2010).
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Method Two
Another method used to test for mercury and approved by the EPA is Method 245.1. This
method uses the Cold Vapor Atomic Absorption Spectroscopy (CVAAS) (Appendix VII) and is
applicable to drinking, surface, and saline waters, domestic and industrial wastes.
The procedure for this method involves the transfer of 100 ml, or an aliquot diluted to 100
ml, containing not more than 1.0 ug of mercury to a 300 ml BOD bottle. Five millitres of sulfuric acid
and 2.5 ml of concentrated nitric acid would then be added, mixing after each addition. About 15 ml
of potassium permanganate solution would be added next to each sample bottle. The sample
would then be shaken and portions of potassium permanganate solution would be added, if
necessary, until the purple color persisted for at least 15 minutes. About 8 ml of potassium
persulfate would then be added to each bottle and heated for 2 hours in a water bath at 95°C. The
sample would then be cooled and 6 ml of sodium chloride-hydroxylamine sulfate would be added
to reduce the excess permanganate. After a delay of at least 30 seconds 5 ml of stannous sulfate
would be added and attached to the bottle immediately to the aeration apparatus (Kopp et al.,
1972).
This procedure is coupled with a physical method known as the flameless AA procedure
and is based on the absorption of radiation at 253.7 nm by mercury vapor. The mercury is reduced
to the elemental state and aerated from solution in a closed system. The mercury vapor passes
through a cell positioned in the light path of an atomic absorption spectrophotometer. Absorbance
(peak height) is measured as a function of mercury concentration and recorded (Kopp et al., 1972).
One major advantage of using this method is that it uses the CVAAS which is known to be
the method of choice when testing for mercury in water. This is because the method is highly
sensitive for mercury in water and is very reliable (Federal Research in Progress, 1998). The
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disadvantage of this method is that it is an old and less sensitive method used in the 1970’s
although analysis of mercury in water bodies proved successful (Tekran Instruments Corporation,
2006). The method used simply cannot measure really low detection limits. The lowest detection
limit for mercury using an EPA-approved method was 0.2 g/l, using Method 245.1 (PutmanMedia,
2010).
Method Three
Method three for this research discusses the upgrade or revision of Method 245.1. It is
called EPA Method 1631 Revision E (1631E) and is a performance based analytical test method
used to determine low level mercury in water by oxidation, purge and trap and Cold Vapor Atomic
Fluorescence Spectroscopy (CVAFS) (Appendix VIII). There are two ways in which Method 1631E
differs from Method 245.1. Firstly, Method 1631E pre-concentrates the atomic mercury vapor on a
gold trap and secondly it uses atomic fluorescence instead of atomic absorption (Carroll, 2006).
In fluorescence, the light source and detector are placed at right angles to each other so
that only light that has been absorbed and reemitted by the analyte reaches the detector. With this
instrument, measurements of trace amounts of volatile heavy metals such as mercury, cold vapour
AFS makes use of the unique characteristic of mercury that allows vapour measurement at room
temperature. Free mercury atoms in a carrier gas are excited by a collimated ultraviolet light source
at a wavelength of 253.7 nm and the excited atoms re-radiate their absorbed energy (fluoresce) at
this same wavelength (Wikimedia Foundation Inc., 2010).
There are many reasons why the upgrade of Method 245.1 was needed. Firstly, although
Method 245.1 worked well in determining mercury levels in various water bodies, the EPA decided
that new water quality criteria required lower limits. The current limit for wildlife was 1.3 ng/L and
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21
Method 245.1 reported limits at 200 ng/L. Secondly the Clean Water Act (CWA) demanded qualitybased strategies to ensure that water quality standards were achieved and maintained. This
included mercury. Thirdly, while this demand was in process, the Great Lakes Initiative, U.S. and
Canada, called for the elimination of mercury through pollution reduction. Lastly, there was the
National Toxics Rule which established maximum concentration limits for mercury and other
pollutants (Carroll, 2006).
The procedure for this method is very lengthy but the method can be summarized in the
following steps:

A 100- to 2000-mL sample is collected directly into a cleaned, pretested, fluoropolymer or
glass bottle using sample handling techniques designed for collection of mercury at trace
levels.

For dissolved Hg, the sample is filtered through a 0.45µm capsule filter prior to
preservation.

The sample is preserved by adding either pretested 12N hydrochloric acid (HCl) or
bromine monochloride (BrCl) solution. (If a sample will also be used for the determination
of methylmercury, it should be preserved according to procedures in the method that will
be used for determination of methylmercury).

Prior to analysis, all Hg in a 100-mL sample aliquot is oxidized to Hg(II) with BrCl.

After oxidation, the sample is sequentially reduced with NH2OH@HCl to destroy the free
halogens, then reduced with stannous chloride (SnCl2) to convert Hg(II) to volatile Hg(0).

The Hg(0) is separated from solution either by purging with nitrogen, helium, or argon, or
by vapor/liquid separation. The Hg(0) is collected onto a gold trap.
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
22
The Hg is thermally desorbed from the gold trap into an inert gas stream that carries the
released Hg(0) to a second gold (analytical) trap. The Hg is desorbed from the analytical
trap into a gas stream that carries the Hg into the cell of a cold-vapor atomic fluorescence
spectrometer (CVAFS) for detection (Environmental Protection Agency, 2001).
For this method either a bubbler or flow-injection system for determination of mercury in water
is used (Environmental Protection Agency, 2002). The flow-injection system is an automated
method in which a sample is injected into a continuous flow of a carrier solution that mixes with
other continuously flowing solutions before reaching a detector (Wikimedia Foundation Inc., 2010).
This method has a lot of advantages to its use in that it allows detection of mercury at 0.5
ng/L, improves accuracy and precision at low levels, supports measurements at ambient water
quality levels and is performance based which means the method can be modified provided that
demonstration of the modification achieves performance equivalent or superior to the performance
Method 1631E. In addition to these advantages, there are a benefits included in the use of the
instrument (CVAFS) i.e. the fluorescence technique is generally considered more sensitive, the
device has better linearity and a more stable baseline than atomic absorption. Also, instruments
designed for Method 1631E typically produce detection limits on the order of 0.05 ppt (Carroll,
2006).
While there are numerous advantages to the use of this method, there are also
disadvantages which may interfere with the quality of data obtained. Collection of sample is vital in
this process as without proper collection of the sample, data may be hampered. In addition,
preparation and analysis of the sample are also very important in this process as contamination
may occur (Carroll, 2006).
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CHAPTER VI
Mitigation Measures
While contamination in rivers and lakes can occur and accumulate over time, it is
extremely important that mitigation measures be put in place to avoid contamination of the
sediment, water and species that live there. There are a variety of regulations which have been
created to assist in the lowering of current mercury levels. This chapter discusses briefly three
important mitigation measures which are believed to be a great contribution in the lowering of these
levels. These alleviation methods include the National Toxics Rule, Great Lakes Water Quality
Initiative and the Clean Water Act.

National Toxics Rule
The Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic
Pollutants, also referred to as tthe ‘National Toxics Rule’ is a rule which publicizes for 14
States, the chemical-specific, numeric criteria for priority toxic pollutants necessary to bring all
States into compliance with the requirements of section 303(c)(2)(B) of the Clean Water Act
(CWA). The primary focus of this rule is the inclusions of the water quality criteria for
pollutant(s) in State standards as necessary to support water quality-based control programs.
In developing this rule, emphasis was placed on two important facts. For a few States, the EPA
is promulgating a limited number of criteria which were previously identified as necessary in
disapproval letters to such States, and which the State has failed to address. For other States,
Federal criteria are necessary for all priority toxic pollutants for which EPA has issued section
304(a) water quality criteria guidance and that are not the subject of approved State criteria
(Environmental Protection Agency, 2010).
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This rule is important for several environmental, programmatic and legal reasons. First,
control of toxic pollutants in surface waters is an important priority to achieve the Clean Water
Act's goals and objectives. Second, as States and EPA continue the transition from an era of
primarily technology-based controls to an era in which technology-based controls are
integrated with water quality-based controls, it is important that EPA ensures timely compliance
with CWA requirements (Environmental Protection Agency, 2010).
Although is rule dictates information regarding the criteria for priority toxic pollutants, it
has not developed both aquatic life and human health section 304(a) criteria for all of the 126
priority toxic pollutants. The human health criteria 91 priority toxic pollutants which are divided
into a criterion where there is a column for water consumption (i.e., 2 liters per day) and
aquatic life (fish and shellfish such as shrimp, clams, oysters and mussels) consumption (i.e.,
6.5 grams per day of aquatic organisms), and another column which shows aquatic life
consumption only (Environmental Protection Agency, 2010).
According to the EPA’s criteria chart for the National Toxics Rule, the following should
be applied to mercury as a toxic pollutant:
Freshwater: Maximum Criterion Concentration – 2.1 µg/L
Continuous Criterion Concentration – 0.012 µg/L
Human Health (10-6 risk for carcinogen) for consumption:
Water and Organisms – 0.14 µg/L
Organisms only – 0.15 µg/L
These values are significant in that they outline the limits for mercury in rivers and lakes as well
as consumption (Environmental Protection Agency, 2010).
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
25
Great Lakes Water Quality Initiative
The Great Lakes are a collection of lakes spanning over 750 miles across the
United States. It includes lakes within various states such as Illinois, Indiana, Michigan,
Minnesota, New York, Ohio, Pennsylvania and Wisconsin along with the province of
Ontario. These areas cover about 95% of the fresh water within the United States. The
lakes provide drinking water, energy, recreation and transportation and are also used for
agriculture and industrial purposes. The initiative began because there were effects of
pollution within the basin. Due to this important fact the EPA along with the Great Lakes
States set out to find the best up-to-data scientific information to better protect the public’s
health and the environment (Environmental Protection Agency, 2010).
The main objective of the Great Lakes Water Quality Initiative is to express each
country’s commitment to restore and maintain the chemical, physical and biological
integrity of the Great Lakes Basin Ecosystem and include a number of objectives and
guidelines to achieve these goals. It reaffirms the rights and obligation of Canada and the
United States under the Boundary Waters Treaty and has become a major focus of
Commission activity. Additions of the initiative address atmospheric deposition of toxic
pollutants, contaminated sediments, groundwater, and nonpoint sources of pollution. There
were also other additions to the initiative which were added to incorporate the development
and implementation of remedial action plans for Areas of Concern and lakewide
management plans to control critical pollutants (Environmental Protection Agency, 2010).
The Water Quality Guidance for the Great Lakes System focuses on chemicals
that are persistent and can bioaccumulate. Mercury has been listed as one of these
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26
pollutants and is said to be long lasting throughout the Great lakes ecosystem and along
with other types of pollutants, is most likely to bioaccumulate in the food chain
(Environmental Protection Agency, 2010).

Clean Water Act
The Clean Water Act, commonly abbreviated as CWA, is the primary federal law in
the United States governing water pollution. The act was developed to establish the goals
of eliminating releases of high amounts of toxic substances such as mercury into water
(Wikimedia Foundation Inc., 2010).
Under the CWA, states adopt water quality standards for their rivers, streams,
lakes, and wetlands. These standards identify levels for pollutants, including mercury that
must be met in order to protect human health, fish, and wildlife. A permit is required at all
times if a person wishes to discharge pollutants, including mercury, into waters
(Environmental Protection Agency, 2010). It is important to mention that provisions within
the CWA do not apply to groundwater contamination as provisions for groundwater is
covered within the Safe Drinking Water Act (Wikimedia Foundation Inc., 2010). Also under
the Act, either EPA or U.S. states issue permits, which must include limits that ensure the
water quality standards are met. In addition, EPA and U.S. states issue information to the
public on waters contaminated with mercury and on the harmful effects of mercury, identify
the mercury sources and reductions needed to achieve water quality standards, and warn
people about eating fish containing high levels of methyl mercury (Environmental
Protection Agency, 2010).
_____________________________________
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CHAPTER VII
Conclusion
As stated earlier in this document, there is only a small percentage of accessible fresh
water in the U.S. This makes testing as well as preventing mercury contamination in rivers and
lakes extremely important. This however, is not the only reason why testing for mercury is
important in these areas. Another reason is mercury’s high toxicity levels and its threat to the
aquatic environment and humans. Together, these reasons create a foundation for examining the
technology used to investigate mercury contamination in rivers and lakes.
To satisfy the objectives of this document, identification of the various causes and effects
of mercury and its components, discovery of the technological devices, equipment and
advancements and how they work together to lower or remove mercury within rivers and lakes and
finally revision of the methods that play a vital role in obtaining measurements along with their
advantages and disadvantages were closely examined. This document has also answered all of
the study questions mentioned earlier which included the identification of the sources of mercury
on the aquatic environment such as rivers and lakes, the methods and devices used to test for
mercury in these types of water bodies and the advantages and disadvantages of using these
types of methods and devices, all of which coincide with the main objectives in this document.
With this in mind, this research paper reiterates the facts as to why the devices and
methods used to test for this toxicant are important. This document has thoroughly reviewed some
of the EPA methods used such as 200.8, 245.1 and 1631E which require the use of various
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devices such as the ICP-MS, CVAAS and CVAFS respectively. Also reiterated are the advantages
and disadvantages of these methods.
As an important note to this document, it would be impractical not to mention that once the
methods and devices have been used to test for mercury in the rivers and lakes across America, it
is expected that an assessment, plan of action, mitigation and treatment would be carried out.
Although this document focuses mainly on mercury testing devices and methods, there are
documents that fulfill knowledge requirements on the areas of assessment (Mercury Hot Spots of
North America, Commission for Environmental Cooperation, 2010), plan of action (Regulatory
Actions, Environmental Protection Agency, 2010 and New Jersey Mercury Reduction Action Plan,
New Jersey Department of Environmental Protection Mercury Workgroup, 2009) and treatment
(The Great Lakes Water Quality Agreement, Environmental Protection Agency, 2010). In this
manuscript however, mitigation measures, which covers prevention and the possibility of lowering
the levels of the toxicant, was the only factor briefly reviewed. Together, all components within this
document are believed to be a critical key in revitalizing the focus of testing mercury using the
necessary methods and devices. In lieu of this, it is expected that this research paper would be
used to bring awareness on some of the important factors of the toxic pollutant and how these
methods and devices could aid in its detection in the rivers and lakes in the U.S.
December 6th, 2010