Rutgers The State COVID 19 Lockdown and Domestic Violence in Bangladesh Paper Hi I have assignment to do ,in the same way that described below. Chapter 10N | Course Hero

Rutgers The State COVID 19 Lockdown and Domestic Violence in Bangladesh Paper Hi I have assignment to do ,in the same way that described below. Chapter 10News Story students will find a news story (local, regional, or international) that relates to the topics (Chapters) covered that week. A ONE paragraph summary of the news story news story and a link to the news story.the chapter is attached. Essential Environment: The Science Behind the Stories
Sixth Edition
Chapter 10
Environmental Health
and Toxicology
Lecture Presentations prepared by
James Dauray
College of Lake County
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This lecture will help you understand:
• Explain the goals of environmental health and identify major
environmental health hazards.
• Describe the types of toxic substances in the environment,
factors that affect their toxicity, and the defenses that organisms
have against them.
• Explain the movement of toxic substances and how they affect
organisms and ecosystems.
• Discuss the approaches used to study the effects of toxic
chemicals on organisms.
• Summarize risk assessment and risk management.
• Compare approaches to risk and regulatory policy.
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Poison in the Bottle: Is Bisphenol A Safe? (1 of 3)
• The chemical bisphenol A (BPA) is in
hundreds of everyday products, yet it
has been linked to breast cancer,
prostate cancer, and heart disease.
– BPA is an additive used to make
the coatings of metal cans, dental
sealants, and the polycarbonate
plastic found in water bottles, toys,
and electronics.
• Many plastic products also contain a
class of hormone-disrupting
chemicals called phthalates.
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Poison in the Bottle: Is Bisphenol A Safe? (2 of 3)
• Many studies have examined the relationship between
BPA, phthalates, and a wide range of adverse health
effects.
Figure 10.1 Studies have linked elevated blood/urine BPA concentrations to numerous health
impacts in humans.
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Poison in the Bottle: Is Bisphenol A Safe? (3 of 3)
• Research finding correlations between BPA and phthalate
exposure and a variety of health problems has caused
some governments to issue regulations.
– Canada has banned BPA use outright.
– The United States restricts its use in children’s
products.
• Many food companies are phasing these out of food
packaging and labeling packaging as BPA- or phthalatefree.
• This is one example of how a society assesses health risks
and decides how to manage them.
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Environmental Health
• Environmental health is a field that assesses
environmental factors that can influence our health and
quality of life.
– These include both natural and anthropogenic factors.
• Environmental hazards are categorized into four types,
each of which carries some risk that is avoidable and some
that is not.
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We face four types of environmental hazards (1 of 4)
• Physical hazards arise
from natural environmental
processes, such as UV
radiation from sunlight and
natural disasters.
– These risks can be
reduced with protective
measures, such as
sunblock and disaster
detection and warning
systems.
Figure 10.2 Environmental health hazards
come in four types.
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We face four types of environmental hazards (2 of 4)
• Chemical hazards include
synthetic chemicals such as
pharmaceuticals, disinfectants,
and pesticides, and natural
toxins like venom.
[Figure 10.2 Continued]
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We face four types of environmental hazards (3 of 4)
• Biological hazards result
from interactions with other
organisms, such as viruses,
bacteria, insects, or parasites.
– Infectious disease are
illnesses that can be
spread from person-toperson.
– Vectors are organisms
that transfer diseases to
their host.
[Figure 10.2 Continued]
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We face four types of environmental hazards (4 of 4)
• Cultural hazards occur as the
result of our place of
residence, socioeconomic
status, occupation, or
behavioral choices.
– Choosing to smoke,
accompanying people who
smoke, poor diet, drug use,
and workplace hazards are
all examples.
[Figure 10.2 Continued]
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Disease is a major focus of environmental health (1 of 2)
• Infectious and noninfectious diseases cause the majority of human
deaths worldwide.
• Noninfectious diseases develop without the action of a foreign
organism.
Figure 10.3 Infectious diseases are the second-leading cause of death worldwide.
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Disease is a major focus of environmental health (2 of 2)
• Infectious diseases spread when a pathogenic organism enters a host
through the skin, via the respiratory system, or by the consumption of food
or water.
– Immunization, public sanitation, access to clean water, food security,
and public education all help to reduce infectious disease.
Figure 10.3 Infectious diseases are the second-leading cause of death worldwide.
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Toxicology is the study of chemical hazards
• Toxicology is the science of examining the effects of
poisonous substances on humans and other organisms.
– Toxicity is the degree of harm caused by a chemical
substance called a toxicant.
• Any chemical has the potential to be a toxicant, depending
on the dose and level of exposure.
• Environmental toxicology is the study of anthropogenic
chemicals released into the environment that have human
health effects.
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Many environmental health hazards exist indoors (1 of 2)
• Cigarette smoke and radon are leading indoor health
hazards and the top two causes of lung cancer.
– Radon is a radioactive gas that seeps up from certain
types of bedrock. It is colorless and undetectable
without specialized kits.
• Asbestos is a substance that was used in the past as
insulation in walls and other products and is highly toxic
when inhaled.
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Many environmental health hazards exist indoors (2 of 2)
• Lead is a heavy metal that, when ingested, damages the
brain, liver, kidney, and stomach.
– This condition is called lead poisoning and has greatly
declined since the phaseout of lead-based paint and
leaded gasoline in the 1970s.
• Polybrominated diphenyl ethers (PBDEs) are
compounds used as fire retardants in a variety of products,
including electronics, plastics, and furniture.
– Similar to BPA, PBDEs act as hormone disruptors,
interfering with thyroid hormones.
– The European Union banned PBDEs in 2003, but they
have not yet been addressed in the United States.
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Risks must be balanced against rewards
• Chemicals have played a crucial role in increasing our
standard of living, but their use carries a potential human
health risk.
• Toxicologists try to weigh the benefits and risks of each
chemical to determine whether it should be widely used.
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Toxic Substances and Their Effects on
Organisms
• The environment contains many natural toxic substances,
such as petroleum, radon gas, and toxins.
– Toxins are toxic chemicals manufactured in the tissues
of living organisms, often used as defense against
others.
• We are also exposed to many synthetic (artificial, manmade) chemical substances.
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Silent Spring began the public debate over synthetic
chemicals (1 of 2)
• Prior to the 1960s, pesticides were indiscriminately
sprayed over residential neighborhoods and public areas,
on an assumption that the chemicals would not harm
people.
• Rachel Carson published Silent Spring in 1962, using
scientific studies and case histories to demonstrate that
pesticides like DDT were harmful to people.
– Although the chemical industry challenged the book,
public outcry led to the banning of DDT in the United
States.
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Silent Spring began the public debate over synthetic
chemicals (2 of 2)
• Synthetic chemicals,
such as DDT, take many
routes traveling through
the environment.
Figure 10.4 Synthetic chemicals take many
routes in traveling through the environment.
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Not all toxic substances are synthetic
• Many toxic substances exist naturally in the environment
and in the foods we eat.
– It is a mistake to assume that all artificial substances
are unhealthy and all natural substances are healthy.
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Toxic substances come in different types (1 of 3)
• Carcinogens are substances or types of radiation that
cause cancer.
– Cancer occurs when malignant cells grow
uncontrollably, creating tumors and often leading to
death.
• Mutagens are substances that cause genetic mutations in
the DNA of organisms.
– Most mutations have little or no effect, but some can
lead to severe problems like cancer.
• Teratogens specifically cause birth defects.
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Toxic substances come in different types (2 of 3)
• Neurotoxins such as heavy metals damage the nervous
system.
• Allergens overactivate the immune system, causing an
immune response when one is not necessary.
– One hypothesis for the recent increase in asthma is the
prevalence of allergenic synthetic chemicals.
• Pathway inhibitors block one or more steps in important
biochemical pathways.
– Cyanide, for example, interrupts the chemical
pathways that produce energy in mitochondria.
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Toxic substances come in different types (3 of 3)
• Endocrine disruptors interfere with the functions of body
hormones, either by blocking them, accelerating their
breakdown, or mimicking their effects.
– Both BPA and phthalates are endocrine disruptors, with
BPA mimicking the female hormone estrogen.
Figure 10.5 Many endocrine-disrupting substances mimic the chemical structure of hormone
molecules.
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Organisms have natural defenses against toxic
substances
• Organisms have evolved ways to tolerate harmful
substances naturally present in the environment to gain an
evolutionary advantage.
– Skin, scales, and feathers resist uptake from the
surrounding environment.
– Metabolic pathways can break down toxic substances
or make them water soluble so they can be excreted
through the kidneys.
• Substances that cannot be metabolized are sequestered
by the body in fatty tissues to protect vital organs.
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Individuals vary in their responses to hazards
• An individual’s sensitivity to a given toxin will vary
depending on genetics, overall health, gender, and age.
– In general, those in poorer health, individuals of smaller
size, and younger organisms with developing organ
systems tend to be more sensitive.
– The EPA extrapolates chemical exposure standards for
adults down to infants and children.
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The type of exposure can affect the response
• The risk of a hazard also varies according to whether a
person experiences high exposure for short periods of time
(acute exposure) or low exposure for long periods of time
(chronic exposure).
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Toxic Substances and Their Effects on
Ecosystems
• When toxicants concentrate
in environments and harm
the health of many
individuals, populations of
the affected species can
become smaller.
– One example of this is
the contamination of the
Earth’s polar regions
that occurs as a result of
natural patterns of
global atmospheric
circulation.
Figure 10.6 Air and water currents direct
pollutants to the poles.
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Toxic substances may concentrate in water
• Toxic substances are not evenly distributed in the
environment and move about in specific ways.
– Water running off from land often transports toxicants
from large areas and concentrates them in surface
water.
– Wastewater treatment plants add toxins,
pharmaceuticals, and detoxification products to
waterways.
– Chemicals in soil can leach into groundwater and
contaminate drinking water supplies.
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Some toxicants persist in the environment
• The rate at which a substance degrades in the
environment depends on its chemistry and on external
factors like temperature, moisture, and sun exposure.
• We have designed many chemicals, such as those in
plastics, to be persistent and resist degradation.
– Over time, most toxicants degrade into simpler
compounds called breakdown products, which may
be less or equally harmful as the original substance.
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Toxic substances may accumulate and move up the
food chain (1 of 2)
• Substances that are fat or oil soluble are absorbed and
stored in body tissues.
– Given enough time and exposure, bioaccumulation
will occur, and the concentration of the substance in
the animal’s tissues will exceed that of the
environment.
• Toxic substances that bioaccumulate will be transferred to
other organisms as predators consume prey.
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Toxic substances may accumulate and move up the
food chain (2 of 2)
• As predators ingest more
and more prey over time,
biomagnification occurs,
resulting in greater and
greater concentrations of
the toxin.
– Biomagnification of DDT
caused many North
American birds of prey
to decline from the
1950s through the
1970s due to a thinning
of the shells of the eggs
they would lay.
Figure 10.7 In a classic case of biomagnification,
DDT becomes highly concentrated in fish-eating
birds such as ospreys.
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Studying Effects of Hazards
• Determining the health effects of a hazard is complex.
• Wildlife toxicologists take measurements, document
patterns, and generate hypotheses in the field before
conducting controlled experiments in the lab.
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Wildlife studies integrate work in the field and lab (1 of 2)
• Biologist Louis Guillette compared blood samples
of alligators in lakes that received agricultural runoff
with those in cleaner lakes and found hormonal
imbalances in those exposed to pesticides.
– Males had low levels of testosterone, while females
had elevated levels of estrogen.
• He followed this up with lab experiments demonstrating
that atrazine, an herbicide, was inducing production of an
enzyme that converts testosterone to estrogen.
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Wildlife studies integrate work in the field and lab (2 of 2)
• Researcher Tyrone Hayes
found similar reproductive
problems in frogs and
attributed them to atrazine
as well.
– Male frogs raised in
contaminated water
became feminized and
hermaphroditic.
– Field surveys confirmed
that leopard frogs in
areas of heavy atrazine
usage had hormonal
problems.
Figure 10.8 Wildlife studies examine the effects
of toxic substances in the environment.
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Human studies rely on case histories, epidemiology,
and animal testing (1 of 2)
• The process of observation and analysis of individual
patients is known as a case history approach.
– Case histories help us understand disease, but tell little
about probability, risk, and population-level effects.
• Epidemiological studies are large-scale comparisons
among groups of people.
– Involves tracking groups of people for a long period of
time and looking for observable differences in rates of
deaths, cancer, and other health problems.
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Human studies rely on case histories, epidemiology,
and animal testing (2 of 2)
• The epidemiological process is akin to a natural
experiment in which the experimenter studies groups of
research participants made available by some event that
has occurred.
– These experiments do not confirm that the health
hazard actually causes the effect.
• Establishing causation requires manipulative experiments
that are not ethically possible with human subjects.
– Animals, such as mice and rats, are used in place of
humans, because their bodies function similarly to
ours.
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Dose-response analysis is a mainstay of toxicology (1 of 4)
• A dose-response analysis involves quantifying the
toxicity of a substance by measuring its effects on animals
at different doses.
– The dose is the amount of substance the animal
receives.
– The response is the type of magnitude of toxic effects
the animal exhibits as a result of the dose.
• Data from this analysis is plotted on a graph, with dose on
the x-axis and response on the y-axis.
– This generates a dose-response curve.
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Dose-response analysis is a mainstay of toxicology (2 of 4)
• The amount of substance
needed to kill half the
population of study
animals, the LD50, is
determined from the
curve.
– A high LD50 indicates
low toxicity.
– A low LD50 indicates
high toxicity.
Figure 10.9 Dose-response curves show that
organisms’ responses to toxicants may sometimes
be complex.
• For a nonlethal toxicant,
an effective dose–50% or
ED50–may be measured
instead.
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Dose-response analysis is a mainstay of toxicology (3 of 4)
• Responses to some toxicants only occur above a certain
dose, or threshold.
– This is called a threshold dose and is observed when
the body’s organs can metabolize or excrete a toxicant
at low doses but get overwhelmed at high doses.
[Figure 10.9 Continued]
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Dose-response analysis is a mainstay of toxicology (4 of 4)
• Responses may decrease as a dose increases, producing
U-shaped or J-shaped curves.
– This type of curve is often the result of endocrinehormone disruptors, as the body is geared to respond to
minute doses.
[Figure 10.9 Continued]
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Chemical mixes may be more than the sum of their
parts
• Mixed toxicants may sum, cancel out, or multiply each
other’s effects.
– The DDT breakdown product DDE can either help
cause sex reversal or inhibit it in alligators, depending
on the presence of other chemicals.
• Synergistic effects occur when the interactive impacts of
chemicals are greater than the sum of their individual
effects.
– Toxicology attempts to use complex experimental
designs to incorporate these effects, but they are
largely unknown.
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Endocrine disruption poses challenges for toxicity
• Because so many synthetic chemicals exist at very low
concentrations over mass areas, their dangers aren’t fully
known.
• Scientists have found that elevated levels of BPA exposure
are linked to:
– Higher breast cancer rates in women.
– Elevated rates of erectile dysfunction and reduced
sperm counts …
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