Download Environmental Chemistry

HOLY CROSS COLLEGIATE
Environmental Chemistry
Student Notes Package
Mrs. Sample
Science 9
Chemicals and Human Nutrition
Chemicals are essential for all life on earth.
Examples: _____________________________________________________________________
_____________________________________________________________________
Organic and Inorganic Substances
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The human body requires 25 different chemicals for normal growth. These necessary
nutrients can be classified as organic and inorganic
o Organic compounds: _____________________________________________________
o Inorganic compounds: ____________________________________________________
Essential Substances
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Only green plants can form many of the organic compounds that our bodies require, while
animals modify others.
The organic nutrients that are essential for health are classified into four major groups:
Carbohydrates, proteins, lipids (fats), and vitamins.
Carbohydrates
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Carbohydrates are organic molecules made up of atoms of carbon, hydrogen, and oxygen
They are primarily used in the human body as an energy source
Dietary sources of carbohydrates:
o _____________________________________________________________________
Proteins
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Proteins are organic compounds made up of amino acids
o Each protein has its own unique number, combination, and arrangement of amino acids
Functions of proteins include growth and repair of body tissues, as well as a source of energy
Dietary sources of proteins:
o _____________________________________________________________________
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Lipids
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Lipids are compounds composed of many carbon, hydrogen, and oxygen atoms
Unused chemical energy is stored as lipids (fat). It is used as an energy source when no other
source is readily available.
Dietary sources of lipids:
o _____________________________________________________________________
Canada’s Food Guide
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Canada’s Food Guide was first introduced in 1942, to prevent nutritional deficiencies and
improve the health of Canadians during wartime, due to food rationing.
Today, its continued purpose is to promote the health and well-being of Canadians
Having the amount and type of food recommended an following the tips in Canada’s food
guide will help:
o Meet your needs for vitamins, minerals and other nutrients
o Reduce your risk of obesity, type 2 diabetes, heart disease, certain types of cancer and
osteoporosis
o Contribute to your overall health and vitality
During the Apollo 15 mission, astronauts David Scott and James Irwin landed on the Moon.
Although both astronauts were in excellent health before leaving Earth, both Scott and Irwin
developed irregular heart rhythm during moments of high exertion and stress. NASA doctors,
concerned that low gravity might have some negative effect on humans, tested both astronauts
upon their return to Earth. The doctors found that Scott and Irwin had low potassium levels from
eating the highly refined, prepared foods that were supplied to them. As a result of their findings,
potassium enriched foods and snacks were added to the menu of subsequent space missions.
Essential Nutrients
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Other nutrients, made up of elements and compounds, help living organisms survive.
Plants obtain carbon, oxygen and hydrogen from the air, and nitrogen, phosphorus,
potassium, magnesium, calcium and sulfur from the soil. These macronutrients are essential
for plants to grow.
o Macronutrients: _______________________________________________________
There are other elements that are also needed, but not in large quantities. These elements are
called trace elements.
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The body cannot manufacture macronutrients. It can only get them from food.
16 naturally occurring elements are present in all living organisms. Green plants require 18
elements for proper growth and functioning, while humans need 25 elements, which are used
for growth and function.
Element
Symbol
Nutrient
Name
Importance of Element/Nutrient
Macronutrients
N
-
Composition of proteins and nucleic acids
Growth and repair of tissue in plants and in
humans
-
Helps regulate nerve signals and muscle activity
Involved in protein formation
Required to regulate acid/base balance
-
Not actually needed in element form, but sulfur in
amino acids is the basis of all proteins
P
K
Mg
Ca
S
Na
Micronutrients (Trace Elements)
Cl
-
Helps regulate water balance
Plays a role in proper cell membrane function
Component of hydrochloric acid in the stomach
-
Essential component of enzymes regulating protein
formation and carbohydrate metabolism
Fe
Zn
I
3
Se
-
Component of an antioxidant enzyme that helps
prevent decay of cell function
Cu
Mn
F
Cr
Activates vitamin B3 to control use of blood sugar in
energy production
Mo
Co
Think About It
Canada’s Food Guide recommends the balance of nutrients you should try to eat every day. Do
you think you could get the same results by eating from only one food group each day, as long as
you eat from all four food groups over the course of a week? Or from eating twice as much as
normal in one day, then eating nothing the next day? Explain your reasoning.
__________________________________________
__________________________________________
__________________________________________
__________________________________________
__________________________________________
__________________________________________
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Chemicals and Farming
Natural Fertilizers
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Plants naturally obtain the nutrients necessary for survival from the soil surrounding their
roots. These nutrients are returned to the soil during the process of ____________________.
Thus, compost (decomposed organic material) makes excellent natural fertilizer for plants.
Commercial Fertilizers
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In order to facilitate more growth, larger growth, and
faster growth, commercial fertilizers are often added to
crops.
The three numbers on a bag of fertilizer refer to the
percentage of nitrogen, phosphate, and potassium that
is available to plants from that bag of fertilizer.
Nitrogen: promotes better growth for ________________
Phosphates: promotes better growth for ______________
Potassium: promotes better growth for _______________
The artificial production of fertilizers has increased the
amount of nitrogen in the environment by as much as 140
million tons per year.
Crop production has doubled worldwide due to the use of artificial fertilizers.
Pesticides
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Pesticides are chemical agents used to protect crops by reducing the amount of damage
caused by a variety of pests
o Herbicides: _____________________________________________________________
o Insecticides: ____________________________________________________________
o Fungicides: _____________________________________________________________
Pesticides are often costly, and can have harmful effects on the environment
o Ex. DDT (dichlorodiphenyltrichloroethane) is an example of a persistent pesticide that
can remain in the environment for long periods of time. It was widely used to control
insects populations and a variety of human diseases in the 1950s and 1960s. It has since
been banned globally for the numerous consequences it has on the health of both
humans and on ecosystems.
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Uptake of Materials by Producers
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All living organisms need a constant supply of raw materials and energy to produce new cells
for growth, to repair damage and to maintain proper health. Plants take in inorganic
compounds to make organic compounds.
Nutrients enter the roots by ______________________ - the movement of molecules from an
area of high concentration to an area of low concentration. This action continues until the
areas are equal concentrations.
Water moves through plants by a special type of diffusion, called _________________. In
this process, water moves through the walls of the plant's roots from an area where there are
more water molecules to an area where there are fewer water molecules. As the plant uses the
water it draws more up from its roots.
Where organisms live affects how and when they can obtain the nutrients they need.
o Some organisms get the nutrients they need often by restricting other organisms from
getting the same nutrients (__________________________________________).
A substrate is a material on which an organism moves or lives. Some organisms attach
themselves to the substrate, while others obtain their nutrients from their substrate.
Uptake of Materials by Consumers
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Consumers rely on the ingestion of other organisms in order to satisfy their energy and
nutrient requirements.
o Ingestion: ____________________________________________________________
The process of digestion breaks down the chemicals present in food.
o Food is broken down into molecules that are small and soluble, which can then pass
through membranes into your blood. These chemicals (nutrients) are then carried
throughout your body to the cells which need them for energy, growth, body building
and cell repair.
Consumers use the organic compounds made by plants for their energy, growth and repair.
When organisms take in these compounds, other substances are also taken. These substances
may be harmless or harmful. By knowing how plants use each element, agriculturalists can
diagnose deficiencies and excesses, and act accordingly, to alleviate the problem.
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Chemicals and the Ecosystem
Biological Monitoring
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All wastes entering the environment are potentially harmful and must be broken down into
nonpolluting compounds, or be treated to reduce the harmful effects these wastes can have.
________________________________________ wastes are naturally degraded.
____________________________ pollutants accumulate and take a long time to degrade.
It is the ______________________________ of these wastes that can affect living
organisms. To determine the concentration scientists test wastes, persistent and nonpersistent, to determine how to handle them and deal with their effects in the environment.
Chemicals and Biological Diversity
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Most types of pollution adversely affect water quality and directly affect living organisms.
Microscopic organisms (bacteria) can cause serious health problems if they are present in
sufficient numbers. Samples are taken to identify their presence to avoid contamination of the
water supply.
o Example: Health Canada requires that no E. coli bacteria be detectable in 100 mL of
water before it is deemed safe for human consumption.
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Aquatic Environments are places where __________________________________ live
depending on the pH level and the amount of _______________________________ present.
o Macroinvertebrates: organisms with no backbone that are visible to the human eye
Worms, leeches and midge larva thrive in polluted water, as they require only small amounts
of dissolved oxygen for survival
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Water Quality
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Water quality is determined using chemical and biological indicators according to what the
water is going to be used for.
Chemical indicators of water quality include: dissolved oxygen, acidity, heavy metals,
nitrogen, phosphorus, pesticides, salts, and turbidity.
Chemical Concentrations in Water
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A pollutant is any material, or form of energy, that can cause harm to living organisms.
Pollution is _______________________________________________________________
that produces a condition which threatens living organisms.
To determine if something is a pollutant or pollution, we must determine how much of it is
present.
Concentrations are usually measured in parts per million (ppm)
o One part per million means that one unit of an element or chemical can be found in one
million units of solution.
o Example: 1 ppm means there is one gram of chemical dissolved in 1000 L of water, or 1
mg of chemical dissolved in 1 L of water.
ppm =

grams of solute
mg of solute
× 106 =
grams of solution
L solution
Some substances are measured in ppb (parts per billion) or even ppt (parts per trillion)
Allowable Concentrations of Chemicals in Canadian Drinking Water
(Source: Health Canada)
Chemical
Toxic Effects
Allowable Concentration
Aluminum
No adverse health effects in
0.1 – 0.2 ppm
humans
Arsenic
Cancer (lung, bladder, liver,
0.010 ppm
skin)
Chromium VI
Enlarged liver, irritation of
0.05 ppm
the skin, respiratory and
gastrointestinal tracts
Mercury
Irreversible neurological
0.001 ppm
symptoms
Nitrate
Methaemoglobinaemia (blue
45 ppm
baby syndrome), possible
carcinogen
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Toxicity Levels
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Toxicity is the ability of a chemical _____________________________________________.
o _____________ toxicity: when serious symptoms occur after only one exposure to the
chemical
o _____________ toxicity: when symptoms appear only after a chemical accumulates to a
specific level after many exposures over time
A common measurement of the toxicity of a substance is by its Lethal Dose 50.
o LD50: the dose of a chemical that will kill 50 percent of the population to which it is
applied.
The LD50 takes into account that some individuals within the target population may be more
resistant to the toxic effects of the chemical.
Examples of LD50 Levels for Selected Chemicals
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Acidity and Alkalinity
Acids
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Acids taste _________, are soluble in water, react with bases, and have a pH less than 7
Examples: __________________________________________________________________
Bases
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Bases taste _________________, are soluble in water, feel slippery, react with acids, and
have a pH greater than 7.
Examples: __________________________________________________________________
Neutral Substances
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Substances that are neither acidic not basic are said to be neutral.
Examples: __________________________________________________________________
pH Scale
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pH means “power of hydrogen,” and is a measure of the concentration of hydrogen ions
(hydrogen atoms that have lost an electron) in a solution.
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The strength or concentration of an acid or base determines the extent to which it reacts with
water. The reaction changes the electrical conductivity of the water, which can be measured
with a sensitive conductivity test meter.
The pH scale is a way of comparing the relative acidity or alkalinity of a substance.
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pH Indicators
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To identify a substance as an acid, a base, or neutral, an indicator is used.
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A litmus paper test cannot provide a specific pH value, but is a useful tool for classifying a
substance as either an acid or a base.
Meaning of Litmus Paper Tests
The following chart indicates the conclusions that can be drawn about a substance based on the
results of testing it with litmus paper.
Red Litmus Paper turns blue Red Litmus Paper stays red
Blue Litmus Paper turns red
Blue Litmus Paper stays blue
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pH paper will change to a colour that is characteristic of a specific pH. These colours are then
matched against a chart that shows the range of colours for known pH values.
Red cabbage juice is a natural indicator that will also change colour for a variety of pH
values.
Other chemical pH indicators include bromothymol blue, bromocresol green, cresol red,
methyl orange, and phenolphthalein.
o Each of these solutions will change in colour when exposed to substances within
particular pH ranges.
Neutralization
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Acids and bases react together when they are mixed. This type of reaction is called
neutralization. Both the acid and the base are used up in this type of reaction.
o The products of neutralization reactions are _____________ and _________________.
Example: Acid in your stomach has a normal pH of
2. This acid helps in the digestion of food and kills
off bacteria. If you eat too quickly, or are under
stress, your stomach produces an excess amount of
gastric acid, giving you heartburn. To neutralize the
excess acid, an antacid tablet is swallowed. This
antacid is a mild base.
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Acid Precipitation
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Sulfur, nitrogen and carbon oxides emitted from industries combine with ________________
in the air to produce sulfuric, nitric and carbonic acid.
These pollutants then fall to the ground as acid precipitation
o Acid precipitation has a pH lower than that of normal rain, which is about 5.6
Some effects of acid precipitation:
o Soil fertility is reduced
o Damages or destroys aquatic
o Kills organisms in lakes and
ecosystems
streams
o Slows tree growth
o Leaches toxic chemicals from the
o Corrodes exposed metal surfaces
soil
o Breaks down stone and limestone
To neutralize acid precipitation, ____________
(calcium hydroxide, a base) is added to lakes.
o This is not necessary in Alberta because the
mountains contain rich deposits of limestone,
making the water naturally basic. When the acid
rain falls, it is neutralized almost immediately.
Preventing Acid Precipitation
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Acid precipitation is caused by sulfur, nitrogen and carbon oxides from industry reacting
with water vapour in the air. Reducing these emissions at the source is a simple, economical
method to prevent acid precipitation.
Modern cars come equipped with __________________________________, which ensures
complete combustion of the hydrocarbon fuel, thus reducing the production of carbon
monoxide and nitrous oxides produced by passenger vehicles.
Thermo-electric power plants that burn coal can be a major source of oxides, depending on
the ______________________________________________ in the coal. These plants utilize
____________________ to reduce oxide emissions. Chemical reactions inside the scrubbers
remove sulfur from the air before it is released into the environment.
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Think About It
1. According to the information in the graph, which of the species is most sensitive to changes
in the pH of the lake? Why?
__________________________________________________
__________________________________________________
2. Which species has the fewest number of organisms present in lake water that has a neutral
pH? How do you know?
__________________________________________________
__________________________________________________
3. If acid rain falls into the lake and changes the pH of the water from 6.3 to 5.0, which species
will increase in concentration? How do you know?
__________________________________________________
__________________________________________________
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Chemicals and Industry
Transfer of Materials through Air
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The source of a pollutant may be in one place, but it can show up in many other places
around the world.
The direction and distance that airborne chemicals travel are determined by various factors,
including
o The properties of the chemical pollutant
o The wind speed
o The direction of the prevailing winds
The distribution of particles may also be limited by lack of __________ or ______________
The source of most airborne particles now is primarily human activities (industries,
agriculture and manufacturing), whereas in the past natural sources (forest fires and
volcanoes) were the main culprits.
Transfer of Materials through Water
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Hazardous chemicals can enter surface water from the air, the groundwater, runoff from
agricultural fields and industrial sites and outflow from storm sewers and sewage treatment
plants.
A substance that dissolves in water easily may be carried by water a fair distance and
dispersed over a wide area.
Substances that do not dissolve easily may sink to the bottom and be concentrated close to
the source, affecting organisms in the immediate area.
Most surface water pollution is a result of washing clothes or watering lawns.
o Nitrates and phosphates enter the water system through storm sewers, runoff or
untreated wastewater.
Treatment of wastewater and sewage is necessary to reduce its harmful effects when it
reenters the water system from which it was taken.
o Certain contaminants can remain collected in the groundwater for long periods of time
(because they are heavy metals), posing problems if the groundwater is used for
drinking, agricultural purposes or industrial use.
A factor that affects the movement of contaminants in groundwater is the number and
connection of pores (tiny spaces between soil grains) in the soil.
o When the pores are packed together very tightly and are not connected, the soil is
considered impermeable.
o If the pores are connected the soil is permeable and water can move through easily.
Permeable ground can create aquifers, which collect naturally filtered amounts of water that
providing a good source of drinking water, accessible when a well is drilled.
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Transfer of Materials through Soil
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Activities around a sanitary landfill often evoke a “not in MY backyard” response. There are
so many negative impacts of landfills that the activities to make sure they are safe must be
monitored daily. The problems that can be encountered include: wind dispersal, scavengers
and disease, leaching into groundwater, as well as methane and carbon dioxide gas
production.
To reduce these problems, a _______________________________ is designed to ensure that
possible negative impacts are addressed and the landfill site is a secure and safe operation.
Biodegradation
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Biodegradation occurs in the environment because living things (earthworms, bacteria and
fungi) are actively breaking down organic substances, including many pollutants. Microorganisms are especially important in the biodegradation of pollutants.
The existing organic molecules provide carbon atoms, which are used to build biological
compounds, such as carbohydrates and proteins. This is a multi-step process in which the
large organic molecules are broken down either inside or outside bacteria.
Some bacteria grow and reproduce only when oxygen is present. They use the oxygen for the
process of ______________________ biodegradation.
When oxygen is not present – in an ________________________ environment (like deep in
landfill sites) – some bacteria remove chlorine from harmful chlorine-containing compounds,
such as PCB’s and replace them with hydrogen atoms, which can be used as food for the
bacteria.
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During the winter biodegradation is slow, because temperature affects the rate of
biodegradation. Other factors include soil moisture, pH, oxygen supply and nutrient
availability.
When chemicals are released in the environment in an uncontrolled manner, the consequences
can be devastating.
Environmental Effects of Exxon Valdez Spill Still Being Felt
By Sarah Graham | December 19, 2003
On March 24, 1989, the Exxon Valdez ran aground in northern Prince William Sound, spilling 42
million liters of crude oil and contaminating 1,990 kilometers of shoreline. Some 2,000 sea
otters, 302 harbor seals and about 250,000 seabirds died in the days immediately following the
spill. Now researchers writing in the journal Science caution that more than a decade later, a
significant amount of oil still persists and the long-term impacts of oil spills may be more
devastating than previously thought.
Charles H. Peterson of the University of North Carolina at Chapel Hill and his colleagues
compiled and analyzed the findings of dozens of previous studies. The results, Peterson
says, "showed that oil has persisted in surprisingly large quantities for years after
the Exxon Valdez spill in subsurface reservoirs under coarse intertidal sediments. This
oil was sequestered in conditions where weathering by wave action, light and bacteria
was inhibited, and toxicity remained for a decade or more." Exposure to this oil, in turn,
caused additional animal deaths. Salmon, for example, had increased mortality for four
years after the spill because incubating eggs had come into contact with it. Larger
marine mammals and ducks, meanwhile, suffered ill effects because their prey was
contaminated. The team estimates that shoreline habitats such as mussel beds affected
by the spill will take up to 30 years to recover fully.
The findings should inform the development of better ways to assess the ecological risks
of large-scale oil spills, the scientists say. In addition, the work applies to other areas of
environmental remediation. "Recognition that chronic exposures of fish eggs to oil
concentrations as low as a few parts per billion lead indirectly to higher mortality shows
the critical need to better control stormwater runoff of petroleum hydrocarbons and
other toxins," Peterson remarks. "In a developed country like the U.S., an amount of
petroleum equal to the Exxon Valdez oil spill is spilled annually for every 50 million
people."
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Fracking wastes may be toxic, tests show
Chemicals in the wastes can fool the body by mimicking hormones or disrupting their
actions
BY BETH MOLE
7:00AM, APRIL 5, 2015
This field of storage tanks (in
yellow) holds fracking
wastewater. At one point, an
estimated 760,000 gallons of
watery wastes were being stored
at this Lamb's Farm Storage
Facility, in Pennsylvania.
DENVER, Colo. — Fracking is
a procedure used to extract oil
or gas from deep
underground. The process
uses lots of water and lots of chemicals. This means it also produces lots of watery wastes. A
series of new tests now show those wastes may be toxic.
Scientists found the wastewater can contain chemicals that alter the action of the body’s
hormones. In mice exposed in the womb, the heart and reproductive tissues did not develop
normally.
Many energy companies around the world use hydraulic fracturing — or fracking — to release
oil, and especially gas. (That gas usually comes from deposits of shale, a type of rock.) But this
process has been controversial. Oil and gas companies inject chemicals deep into wells to flush
out the gas and oil. Those chemicals can contaminate groundwater, some studies have shown.
For the new study, researchers worked with human cells and mice. First, they looked for signs
in cells that the chemicals altered signaling by any of five different hormones. Hormones are
natural chemicals produced by the body’s endocrine system. That system produces hormones
that tell various tissues when to turn on or off a particular important action.
For instance, hormones help people process food, identify hunger and recognize when it’s time
to sleep. Hormones also tell tissues when it’s time to grow. Puberty and reproduction, for
instance, are controlled by a complex series of hormonal changes.
Signs of animal impacts
Christopher Kassotis works at the University of Missouri in Columbia. He’s also the study’s lead
researcher and an endocrinologist (EN-doh-krin-OLL-uh-gizt), someone who studies hormone
impacts. For the new study, his team combined 23 hormone-disrupting chemicals known to
have been used by oil and gas companies for fracking.
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Hormone-like pollutants can do harm in one of two ways. Some may block a true hormone’s
signal. Others may fake out the body, turning on some activity normally triggered by a real
hormone.
Energy companies seldom disclose the precise recipe of chemicals in their fracking fluids. But
lists of some fracking chemicals have been published. (Such ingredients can include chemicals
that kill microbes or that inhibit rust and other forms of corrosion.) Kassotis and his coworkers
tried to mix these chemicals in amounts that might roughly match levels in real fracking
wastewater.
For their new study, the researchers gave pregnant mice drinking water that contained a
cocktail of these fracking chemicals. Male offspring of these mice grew up overweight. Those
males also had heavier hearts compared to mice whose mothers hadn’t drunk water containing
fracking chemicals. (The researchers are still analyzing the data from female offspring.)
Finally, male mice exposed in the womb to the fracking chemicals developed bigger testes.
“This is not actually a good thing,” said Kassotis. Larger testes can lead to cysts and other
health problems, he says.
The effects seen in the male offspring echo health problems seen in people: Studies have linked
other hormone disrupters to obesity. And epidemiologists have found an increased rate of heart
defects in babies whose mothers live near natural gas wells, including fracking sites.
It’s unlikely people would ever encounter doses of fracking chemicals as high as those given to
the mice, Kassotis says. But some human exposures might not be too much lower, he adds.
Fracking fluids and wastewaters often spill, he explains. This can taint soils and rivers. In
January, for example, a leaking pipeline spewed more than 11 million liters (2.9 million gallons)
of fracking wastewater. That pollution entered a stream near Williston, N.D.
Earlier, Kassotis’s team collected samples of soil and water from areas where spills had
occurred in Colorado. Hormone-disrupting chemicals showed up.
How dangerous are these exposures to people? No one knows, says Karl Linden. He’s an
environmental engineer at the University of Colorado Boulder. But he is developing ways to
clean up fracking wastewater. He hopes these techniques will help remove hormone mimicking
pollutants.
Scientists don’t know all of the hormone-like chemicals in fracking fluid yet, Linden notes. But,
he adds, they’re definitely there.
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Record dolphin die-off linked to BP oil spill
Exposure to oil spill caused life-threatening adrenal and lung disease
Thomson Reuters Posted: May 20, 2015 2:31 PM ET Last Updated: May 20, 2015 2:31 PM ET
A record dolphin die-off in the northern Gulf of
Mexico was caused by the largest oil spill in U.S.
history, researchers said on Wednesday, citing a
new study that found many of the dolphins died with
rare lesions linked to petroleum exposure.
Scientists said the study of dead dolphins tissue
rounded out the research into a spike of dolphin
deaths in the region affected by BP Plc's oil spill that
was caused by the 2010 Deepwater Horizon oil rig
explosion.
Millions of barrels of crude oil spewed into Gulf waters, and a dolphin die-off was
subsequently seen around coastal Louisiana, Alabama and Mississippi, according to the
National Oceanic and Atmospheric Administration (NOAA).
"Dolphins were negatively impacted by exposure to petroleum compounds," from the
spill, said Stephanie Venn-Watson, a veterinary epidemiologist at the National Marine
Mammal Foundation and lead author of the study published in the scientific journal
PLOS ONE.
"Exposure to these compounds caused life-threatening adrenal and lung disease that
has contributed to the increase of dolphin deaths in the northern Gulf of Mexico," she
added.
More than 1,200 cetacean marine mammals, mostly bottlenose dolphins, have been
found beached or stranded since the spill, according to NOAA, which has declared an
ongoing "unusual mortality event" under 1972 Marine Mammal Protection Act.
To understand the cause of death, researchers compared tissue samples from 46
dolphins in areas affected by the spill with 106 dolphins that were not exposed.
Dead dolphins near the spill were more likely to have lung damage and pneumonia,
researchers found, explaining the mammals would have inhaled contaminants coming
up for air near the water's surface.
"These dolphins had some of the most severe lung lesions I have ever seen in wild
dolphins throughout the United States," said Kathleen Colegrove, the University of
Illinois-based lead veterinary pathologist for the study.
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