AP Environmental Science
Name: ____________
Chapter 22: Hazardous Chemicals: Pollution and prevention.
Learning Objectives:
1. Toxicology and Chemical Hazards: Explain what toxicology is and how it applies to
many of the chemicals in use in our society; identify the two most toxic chemical groups in
use, and assess their involvement in food chains.
2. Hazardous-Waste Disposal: Describe the three methods employed in land disposal of
hazardous wastes, and relate and give examples of what happened before land disposal came
under regulation.
3. Cleaning Up the Mess: Explain how the Superfund program put in place by Congress
deals with abandoned toxic sites, brown-fields, and leaking underground storage tanks.
4. Managing Current Toxic Chemicals and Wastes: Review the laws put in place to (a)
prevent illegal disposal of toxic wastes, (b) reduce accidents and accidental exposure, and (c)
evaluable new chemicals.
5. Broader Issues: Discuss the issue of environmental justice, and review strategies that
prevent toxic chemicals from being used.
Key Terms and Vocabulary:
Toxicology, acute, chronic, carcinogenic, risk characterization, threshold level, Toxics Release
Inventory (TRI), Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA),
Pollution Prevention Act of 1990, synthetic, halogenated hydrocarbons, chlorinated
hydrocarbons, persistent organic pollutants (POPs), Stockholm Convention on Persistent Organic
Pollutants, best-demonstrated available technologies (BDATs), secure landfill, midnight
dumping, orphan sites, groundwater remediation, Drinking Water Act of 1974, maximum
contaminant levels, groundwater remediation, Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), Superfund, Superfund Amendments and
Reauthorization Act of 1986 (SARA), National Priorities List, bioremediation,
phytoremediation, American Recovery and Reinvestment Act of 2009, brownfields, Brownfield
Act, underground storage tank (UST), discharge permit, Department of Transportation
Regulations (DOT Regs), Occupational Safety and Health Act of 1970, hazard communication
standard, “worker’s right to know”, material safety data sheet (MSDS), Emergency Planning and
Community Right-to-Know Act (EPCRA), Toxic Substances Control Act of 1976 (TSCA),
REACH (Registration, Evaluation, and Authorization of Chemicals), environmental justice.
What are hormones? powerful chemicals that regulate systems and functions in
vertebrates. Produced by endocrine gland and work in very small concentrations.
Released in the blood, bind to cell receptors, and turn on genes or cause other cellular
functions
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What is the Endocrine system: the whole hormone system
Controls metabolism, growth, reproduction
Disturbances to the system are not trivial
Some chemicals can disrupt the endocrine system
What is BPA?
Bisphenol A (BPA) is in plastic food and drink containers
Why does the Food and Drug Administration have “some concern” about BPA’s effects?
It leaches into the containers contents and is ingested
93% of people in the U.S. had it in their urine—especially kids
BPA has estrogenic activity: it simulates estradiol
It binds to estrogen (reproductive hormones) receptors
It causes weight gain, aggressiveness, changed sexual behavior, changes uterus and ovaries,
diabetes
Is BPA dangerous? Consumers want BPA removed
Canada and the European Union are banning it in food containers
What is the Precautionary Principle?
if there is no scientific concensus, act as if something is harmful
•
The chemical industry says BPA is perfectly safe
But they have replaced BPA with other products
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•
The Food Quality Protection Act (FQPA) (1996)
Directs the EPA to develop procedures to test products for endocrine disruption
Toxicology and Chemical Hazards 22.1
Read this whole section and create your own note. It is all important.
What four categories are used to define hazardous chemicals?
The categories are ignitability, corrosivity, reactivity, and toxicity.
A. Dose Response and Threshold—“Human exposure to a hazard is a vital part of its
risk characterization, and such exposure can come through the workplace, food,
water, or the surrounding environment.”
1. Threshold Level—In the dose-response relationship, there is usually a
threshold. Organisms are able to deal with certain levels of many substances
without suffering ill effects. The level below which no ill effects are observed
is called the threshold level.” See Figure 22-2.
The threshold level for harmful effects of toxic pollutants gets lower as
exposure time increases
B. The Nature of Chemical Hazards: HAZMATs—“A chemical that presents a
certain hazard or risk is known as a hazardous material (HAZMAT). The EPA
categorizes substances on the basis of the following hazardous properties.”
C. Hazardous material (HAZMAT):
a. A chemical that presents a certain hazard or risk
D. Substances are classified according to their:
a. Ignitability: catch fire easily (gasoline)
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b. Corrosivity: corrode tanks and equipment (acids)
c. Reactivity: chemically unstable substances that may explode or create
toxic fumes (explosives)
d. Toxicity: injurious when eaten or inhaled (chlorine)
E. Radioactive materials are the most hazardous
See Figure 22-3.
These placards are mandatory on trucks and railcars carrying hazardous
materials— numbers identify the specific materials
F. Sources of Chemicals Entering the Environment—“To understand how
HAZMATs enter our environment, we need to look at how people in our society
live and work.” See Figure 22-3.
1. Toxics Release Inventory—“Requires industries to report releases of toxic
chemicals to the environment, and the Pollution Prevention Act of 1990
mandates collection of data on toxic chemicals that are treated on-site,
recycled, or combusted for energy.” See Figure 22-5.
D. The Threat from Toxic Chemicals—“Fortunately, a large portion of the chemicals
introduced into the environment are gradually broken down and assimilated by
natural processes. After that, they pose no long-term human or environmental
risk, even though they may be highly toxic in acute doses.”
1. Heavy Metals—“The most dangerous heavy metals are lead, mercury, arsenic,
cadmium, tin, chromium, zinc, and copper.”
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2. Organic Compounds—“Petroleum-derived and synthetic organic compounds
are the chemical basis for all plastics, synthetic fibers, synthetic rubber,
modern paint-like coatings, solvents, pesticides, wood preservatives, and
hundreds of other products.”
i. Dirty Dozen—“Most of the ‘dirty dozen’ POPs (Table 22-1) are
halogenated hydrocarbons.” Look at table 22.1 so that you do at least
recognise the chemicals as bad.
ii. A halogenated hydrocarbon, PERC—“Perchloroethylene, or PERC,
etrachloroethylene, is a colorless and nonflammable and is the major
substance in dry-cleaning fluid. Breathing PERC for short periods can
bring on dizziness, fatigue, headaches, and unconsciousness. Over longer
periods, PERC can cause liver and kidney damage.”
These compounds are nonbiodegradable, and they bioaccumulate
E. Involvement with Food Chains—“The trait that makes heavy metals and nonbiodegradable synthetic organics particularly hazardous is their tendency to
accumulate in organisms.”
1. Minamata—“A tragic episode in the early 1970s, known as Minamata
disease, revealed the potential for biomagnification of mercury and other
heavy metals.”
A chemical company near the village in Japan discharged mercury into a river,
which entered the bay
Mercury bioaccumulated and biomagnified
Cats fed fish suffered acute mercury poisoning: spastic movements, paralysis,
coma, and death
150 people who ate fish suffered serious bone and nerve damage—another 50
died
2. Arctic POPs—“Much to research scientists’ surprise, fish, birds, and
mammals all over the Arctic are showing elevated body burdens of a number
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•
•
•
•
of persistent organic
pollutants—in particular, DDT, toxaphene,
chlordane, PCBs, and dioxins.”
See Figure 22-7.
The Inuit people who eat them also have high levels
How did these chemicals get to the pristine Arctic?
POPs are persistent, bioaccumulate, and travel
Cold condensation in the Arctic lets POPs condense on the snowpack and wash
into water during thaws
Cause immune system disorders, disrupted hormone system, cancer, fetal sex changes
Now-banned POPs should let the Arctic air clear
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Hazardous waste disposal 22.2
Legislation has reduced the dumping of pollutants into the environment but we still need to find
safer options for disposal.
Which Act put an end to the widespread disposal of wastes in the atmosphere and waterways?
The Clean Air and Clean Water Acts!
What loophole did these acts leave for the disposal of waste?
Led to indiscriminate land disposal.
Briefly outline the three main methods of disposal on land used since the early 70’s and describe
any problems they may lead to.
1.
Deep-Well Injection—“Deep-well injection involves drilling a borehole thousands of feet
below groundwater into a porous geological formation.”
2.
Surface Impoundments—“are simple excavated depressions (ponds) into which liquid wastes
are drained and held.” See Figure 22-8.
3.
Landfills—“Some 350 million pounds of hazardous wastes were delivered to on-site landfills
in 2010, and an additional 253 million pounds were deposited in off-site landfills.”
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Cleaning up the mess! 22.3 page 561 What act did congress pass in 1974 to ensuring safe drinking water
—“To protect the public from the risk of toxic chemicals contaminating drinking water supplies,
Congress passed the Safe Drinking Water Act of 1974.”
Ground water remediation
—“Techniques involve drilling wells, pumping out the contaminated groundwater, purifying it, and injecting the
purified water back into the ground or discharging it into surface waters.”
What is the Superfund? Page 561 This is very important!!
“Through a tax on chemical raw materials, this legislation provides a trust fund for the identification of abandoned
chemical waste sites, protection of groundwater near the sites, remediation of groundwater if it has been
contaminated, and cleanup of the sites.”
CERCLA
SARA = Superfund amendments and reauthorisation act.
Setting Priorities—“Resources are insufficient to clean up all sites at once. Therefore, a system for setting priorities
has been developed.”
EPA decides which sites need the most attention.
Bioremediation
"In bioremediation, oxygen and organisms are injected into contaminated zones. The organisms feed on and
eliminate the pollutants...and then die when the pollutants are gone."
When the soil contaminants are heavy metals and non-biodegradable “organic compounds, phytoremediation has
been employed with some success.”
What is phytoremediation?
Brownfields
The Brownfield Act “provides grants for site assessment and remediation work and authorized $250 million/year for
the ensuing five years for the program.”
What are greenfields?
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LUSTs
Leaking Underground Storage Tanks (LUSTs)—“One consequence of our automobile-based society is the millions
of underground fuel-storage tanks at service stations and other facilities. Putting such tanks underground greatly
diminishes the risk of explosions and fires, but it also hides leaks.
Fig 22-14
Typical subsurface contamination from a leaking fuel tank at a gas station
After the leak has been repaired, the vacuum-extraction process causes gasoline
and residual hydrocarbons in the soil and on the water table to evaporate and then removes the vapors, preventing
further contamination of the groundwater
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After the leak has been repaired, the vacuum-extraction process causes gasoline
and residual hydrocarbons in the soil and on the water table to evaporate and then removes the vapors, preventing
further contamination of the groundwater
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Managing Current Toxic Chemicals and Wastes 22.4
Production of chemicals will continue
U.S. regulations cover production of hazardous wastes
The Clean Air and Clean Water Acts
Legislation limiting discharges into the air and water
Discharge permit: monitors who is discharging what
Required for any facility (including sewage) that discharges a certain volume into water
Establishments must report all discharges covered by the TRI
Renewal depends on meeting strict standards
•
The Resource Conservation and Recovery Act (1976)
Prevents unsafe or illegal disposal of solid wastes
on land
•
All disposal facilities (e.g., landfills) must have permits
Facilities must have safety features
Old facilities are closed and become Superfund sites
•
Toxic wastes destined for landfills must be
converted to forms that will not leach
Through biodegradation or incineration
•
“Cradle-to-grave” tracking of hazardous wastes occurs now and is controlled by the EPA.
Explain how this works using Figure 22-15
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What is OSHA?
•
Occupational Safety and Health Act of 1970
Its amendments make up the hazard communication standard (worker’s right to know)
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Worker’s right to know: involves businesses,
industries, and labs
They must make information on hazardous materials, along with protective equipment,
available
What are MSDS?
A Material Safety Data Sheet is a technical bulletin that provides specific hazard information, safe
handling information, and emergency procedures for a controlled product.
•
Material safety data sheets (MSDSs): give information on over 600 chemicals
They must accompany chemicals when they are shipped, stored, and handled
Contain information on reactivity and toxicity
Tell what precautions to follow when using the chemical
•
It is the worker’s responsibility to read the information and exercise precautions
http://www.sciencelab.com/msds.php?msdsId=9924285 MSDS for HCl.
Download a MSDS for a chemical of your choice. What would you use this MSDS for?
http://www.cloroxprofessional.ca/pdf/UltraCloroxDisinfectingBleach.pdf
Community protection and emergency preparedness
A 1984 accident at Union Carbide in India spilled 40 tons of methyl isocyanate
An extremely toxic gas
600,000 people were exposed; over 10,500 died
50,000 people had visual impairment, respiratory problems, and other injuries
Union Carbide scaled back safety and alarm systems
The people and doctors had no idea of how to protect or treat themselves
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As a result of the Union Carbide accident Congress introduced legislation to address
the problems of accidents.
Superfund Amendments and Reauthorization Act of 1986 (SARA)
Title III contains the Emergency Planning and Community Right-to-Know Act (EPCRA)
•
EPCRA: companies handling over 5 tons of any hazardous material must account for:
Storage sites, feed hoppers, etc.
Information is sent to a local emergency planning committee (fire and police departments,
hospitals, etc.)
•
The Toxic Substances Control Act (TSCA; 1976):
Chemical industries must submit a “pre-manufacturing notice” to the EPA before massproduction
It details potential environmental and health risks
The EPA may restrict or prohibit the product
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The EPA must use the “least burdensome” approach
Compare the costs and benefits of regulation
Major Hazardous waste laws
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22.5 Environmental Justice and Hazardous waste.
Provide examples of environmental injustices?
•
The largest commercial hazardous-waste
landfill in the U.S. is in Emelle, Alabama
African Americans make up 90% of the population
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Arizona’s Navajo Nation is exposed to dust containing uranium and radium
520 mines operate under government contracts
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870,000 federally subsidized housing units are within a mile of factories that emit toxic
emissions
Most occupants are minorities
The Basel Convention: an international agreement banning most international
toxic-waste trade
The Basel Action Network publicizes and coordinates legal challenges to toxic-waste
shipments
What is Green Chemistry?
•
Substitution: another way to avoid pollution
Finding non-hazardous substitutes for hazardous materials
Wet cleaning: water-based cleaning compounds instead of dry-cleaning chemicals
Products can be biodegradable
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Reuse: cleaning up and recycling chemicals
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Prevention, substitution, and reuse have reduced hazardous-waste releases
Public disclosure of TRI data plays a crucial role
Pollution avoidance can be applied to the individual
Reduce or avoid products with harmful chemicals
Prevents them and their by-products from entering the environment
The average American home contains 100 lbs of household hazardous waste (HHW)
Paints, stains, pesticides, motor oil, etc.
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They must be safely stored, used responsibly, and disposed of properly
In conclusion, there are 4 ways to address chemical pollution
Prevention, recycling, treatment, safe disposal
The first three promote a minimum of waste
Concepts and Connections:
The disposal of hazardous substances on land in response to laws eliminating the
discharge of hazardous substances to air and water is an example of humans not thinking through
the consequence of our actions. Most hazardous waste sites are not a result of malice. We did not
know we were creating a problem. When we passed the Clean Air and Clean Water acts, we
moved the waste from one media to the next, creating new problems in the process; we did not
eliminate the problem because we did not eliminate the production of the pollutants. When we
eliminated the burning of trash in open dumps, we moved pollutants from the disposal of
municipal wastes from the air to the land and water. When we built taller smokestacks to
eliminate local air pollution, we created the conditions for acid deposition miles from the
pollutant source. We need to remember that the Laws of Thermodynamics and the Law of
Conservation of Matter govern human actions. We cannot throw things away because nothing
ever goes away.
Because we have begun to recognize the need to look at the full life cycle of a product we
are moving toward pollution prevention rather than “command and control” technologies. To
build a sustainable society we need to improve our ability to prevent pollution.
Use the review questions to test your understanding.
10. What law was passed to ensure safe land disposal of hazardous wastes? What are the main features of the
legislation?
“The 1976 RCRA and its subsequent amendments are the cornerstone legislation designed to prevent unsafe or illegal disposal of all
solid wastes on land. The RCRA has three main features. First, it requires that all disposal facilities, such as landfills, be sanctioned by
permits. Second, the RCRA requires that toxic wastes destined for landfills be pretreated to convert them to forms that will not leach. For
whatever is still going to disposal facilities, the third major feature of RCRA is to require ‘cradle-to-grave’ tracking of all hazardous wastes.”
12. What role does the Toxic Substances Control Act play in the hazardous waste arena?
“The Toxic Substances Control Act (TSCA) . . . requires that, before manufacturing a new chemical in bulk,
manufacturers must submit a ‘pre-manufacturing report’ to the EPA in which the environmental and human
health impacts of the substance are assessed (including those that may derive from the ultimate disposal of the
chemical). Depending on the results of the assessment, the manufacturer may be required to test the effects of
the product on living things. Following the results of the testing, a product’s uses may be restricted or a product
may be kept off the market altogether.”
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13. Why does the EPA have an environmental justice program?
“The EPA defines environmental justice as ‘the fair treatment and meaningful involvement of all people
regardless of race, color, national origin, or income with respect to the development, implementation, and
enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people,
including racial, ethnic, or socioeconomic group(s), should bear a disproportionate share of the negative
environmental consequences resulting from industrial, municipal, and commercial operations or the execution
of federal, state, local, and tribal programs and policies. Several recent studies have shown that, all across the
United States, waste sites and other hazardous facilities are more likely than not to be located in towns and
neighborhoods where most of the residents are non-Caucasian. These same towns and neighborhoods are also
less affluent, a further element of environmental injustice.”
In-Class Activity 3: Handout 1
Suppose that some mice are fed a chemical called EMBS every day for about two years. They
are then tested for cancer. The results of this test are listed in the table below. Note that animals
are usually given doses based on their body weights, so smaller animals would get relative small
total doses, but still the same in proportion to their weights.
Dose (mg EMBS /
kgmouse body weight / day)
0
3
6
12
Number of
mice
73
69
75
75
Number of mice
with tumors
0
7
16
30
P(Cancer)
0.10
 7 / 69
1. What do these data tell us about the carcinogenic potential of EMBS?
a. Can it cause cancer in mice?
b. Can it cause cancer in humans?
2. Fill in the fourth column, using the example provided as a guide
3. Graph the EMBS dose-response curve on the following page. Does EMBS appear to have
a threshold for mice?
4. Suppose you fed another group of mice 24 mg EMBS / kgmouse body weight / day. How many
would you expect to get cancer? Why?
5. Suppose you fed yet another group of mice 1 mg EMBS / kgmouse body weight / day. How
many would you expect to get cancer? Why?
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P(Cancer)
1.0
0.5
0
3.0
6.0
Dose (mg EMBS / kg / day)
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12.0